Slide 1

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 2

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 3

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 4

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 5

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 6

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 7

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 8

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 9

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 10

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 11

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 12

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 13

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 14

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 15

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 16

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 17

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 18

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 19

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?


Slide 20

SPATIAL AND TEMPORAL CHANGE
OF MANGROVE FOREST
OF MTONI KIJICHI,
DAR ES SALAAM - TANZANIA

Presenter
Mathias Msafiri Igulu
Promotor
Prof Dr Nico Koedam
Co- promotor Dr Farid Dahdouh-Guebas and
Griet Neukermans

Introduction
Mangroves ecosystems ……….

 Occur worldwide on tropical and subtropical coastlines
 Ecologically, they act as breeding, spawning,
hatching and nursery grounds for marine
animals
 They provide construction materials,
charcoal, firewood and are source for
traditional medicines

Introduction
 Mangrove ecosystems are subjected to various
anthropogenic effects like
 urban expansion
 agriculture
 tourism and
 aquaculture impoundments

 In Dar es Salaam City conversion of mangrove
forests to residential and industrial land is the main
threat
 Dar es Salaam city has growth rate of 6.75% per year
 Understanding mangrove dynamics may suggest
conservation and management directives

Objectives
General objective is to examine and interpret short and
long term change in mangrove of Mtoni-Kijichi

• To examine vegetation structure and regeneration
classes of the forest
• To examine long term (decadal) change of the forest by
using aerial photographs and the satellite image
• To link current forest structure with the changes and
propose management strategies

Study site

Dar es salaam

Source

Study site

Mtoni kijichi mangrove

Methodology
Two methodologies
Field survey (transect line plot method)

Remote sensing (aerial photographs and satellite image)

Study area and field methodology
Four transects were sampled, the transects are in the
framework of Peri-urban mangrove forest as filters and
potential phytoremediators of domestic sewage in East
Africa (PUMPSEA) project
Transect and line method was chosen as a standard
method to obtain quantitative descriptions of species
composition and community structure
Total of 32 plots were sampled randomly
Plot size (10 *10 m2)
All trees were identified to species level
Information recorded
1. For adult trees, circumference (G130 cm)&
tree height (m)
2. Regeneration classes (diameter < 8cm)
3. Cut stumps, only counted
Sampling (August-September 2005)

Aerial photographs and satellite image (IKONOS, 2005) processing

Purchased from Ministry of Land and Survey at Dar es Salaam
Year 1969, 1982 and 1992

Photographs scanned at 300 dpi

Imported into ArcGIS
Georeferenced with reference to the satellite image 2005
Assemblages were visually delineated

Sonneratia alba

Ceriops tagal

Saltpan area
Rhizophora mucronata

Avicennia marina

Identification key were made prior to delineation of dominant assemblage (Dahdouh-Guebas et al. 2006)

Results and Discussions (1)
Tree physiognomy
16

150

G130 (cm)

12

8

100

4

50

0

0

N=

(b)

200

(a)

22

10

26

15

1

2

3

4

N=

Transect

22

10

26

15

1

2

3

4

Transect

Box-plots display of adult mangrove Height (a) and G130cm (b) distributions at four transects in Mtoni-Kijichi.

Statistical test shows a significant difference in height and G130 distributions (p < 0.05, ANOVA),
Differences between transect 1-2 & 3-4 (p < 0.05 Post hoc Tukey HSD test)

Results and Discussions (2)
Distribution of species in the forest (Morisita’s index)

Morisita’s Index (Io) values
Transect

Io < 1, Species
evenly dispersed1

2

3 Io

= 1, randomly
dispersed
4

A. marina

0*

0.0010

0.5747

0.0370

B. gymnorrhiza

np

0*

0.0392

0.0157

0.1078

0.0034

0.0003

0*

L. racemosa

np

np

0*

np

R. mucronata

0.0036

0.0005

0*

0*

S. alba

0.0001

0.0017

0.0071

0*

np

0.0354

0*

0.0001

C. tagal

X. granatum

*np, the species was not observed and
value
less that 0.000001.
Io >0*1,
clustered
Io > 1, the population is clustered, if Io = 1, randomly dispersed & Io < 1, evenly dispersed.

Results and Discussions (3)

Regeneration status
Distribution and abundance of regeneration classes

Juveniles(ha -1)

2500
2000
RCI

1500

RCII

Statistical test
p < 0.05
Differences
Between the two
groups

RCIII

1000

RCIV
500
0
1

2

3

4

Transects

Seedlings: RCI (height, h < 40 cm ) , juveniles: RCII (40 < h < 150 cm),
small trees: RCIII (150 < h < 300 cm) and young trees RCIV h > 300cm

Ratio RCI:RCII:RCIII = 2: 1: 1
Kairo et al. (2002) found 86:51:1 (Uyombo) and 62:17:1(Kirepwe) in Kenya
Chong (1988) obtained ratio of 6:3:1(Costa Rica)

Results and Discussions (4)

Cut stumps status

Cut stump (ha -1)

Estimation of cut stumps per hectare
1000
800
600
400
200
0
1

2

3

4

Transects
Large number of cut stumps observed at transect 2
Statistics test shows a significant difference between transect 1 and 2- 4, p < 0.05

Results and Discussions (5)

Vegetation map produced from 1967 aerial photograph

Results and Discussions (6)

Vegetation map produced from 1982 aerial photograph

Results and Discussions (7)
Vegetation map produced from 2005
panchromatic satellite image
Position of dominant
species remained the
same

Results and Discussions (8)

Estimation of total area coverage
Year
1967

1982

1992

2005

Total area inclusive salt pan and cleared areas (ha)

266.72

194.13

202.20

207.83

Total mangrove cover (ha)

219.77

194.13

191.47

179.24

-10.6

-1.4

-5.3

% Change from previous image (mangroves only)

Conclusion
The mangrove of Mtoni-Kijichi comprises small assemblages of S. alba,
A. marina, C. tagal, B. gymnorrhiza and R. mucronata (remote sensing).
Field survey indicated the presence of L. racemosa, and X. granatum.
Taller and bigger trees (G130 > 8 cm) were found close to the river
mouth while shorter and stunted trees dominated the southern
part.
Regeneration class III and IV were more preferred by cutters
Large number of cut stumps were found at transect 2, with estimated
760 stumps per hectare

A total of 40.5 hectares of mangroves have been lost from 1967 to
2005, which corresponds to 18 % of the mangrove cover present in
1967.

Shall we clear all trees and forget that once there was a
mangrove forest here?
Or shall we wait longer till they grow into bigger size?