Transcript PARTHENIUM DISTRIBUTION IN KENYA

Current distribution of parthenium
weed in Kenya and potential impact
on critical ecosystems
Emily Wabuyele
National Museums of Kenya
Some facts on Kenya
• Located in the east-central
part of the African
Continent, astride the
equator
• About 7000 species of
plants, about 50 are IAS
• Agriculture contributes
over 20% of GDP
• Tourism contributes about
10% of GDP and is a top
foreign exchange earner
• Top invaders include
prosopis, water hyacinth,
parthenium
Rationale for surveys Kenya: Status of knowledge
• Parthenium first appeared
in the mid 1970s
• Very little was known on
actual distribution and
extent of invasion by 2009
Parthenium Project focus in Kenya
To establish the actual distribution and extent of
invasion by parthenium weed in Kenya
 Undertook roadside surveys to map occurrence of
the weed in the country
 Information collected on species associated with
parthenium (native and alien)
 Information on local knowledge of the weed
Data Collection: Site data sheet
Locality Details (Geographical coordinates & Altitude)
 Habitat type
Details of invasion
 Current Density (abundance)
 Morphological differences & robustness
Phenological data
 Date first seen
 Associated species (Collect voucher material when possible)
Local knowledge
 Local name
 Is the species used locally (If yes, what is it used for)
 Is the species harmful to livestock or humans?
Survey zones
• Target areas based on
climex predictions and
herbarium records
• Major hi-way surveyed
based on standard
protocol as used in
Ethiopia and RSA
• Data collected in 2010
and 2011
Data Management
• Data points from
surveyed areas
entered into a MS
spreadsheet
• Mapping and spatial
analysis of distribution
patterns in Arc View
(based on Global GIS
database)
Parthenium distribution: 2010, 2011
HABITATS INVADED
HABITATS INVADED
 Invasions are not habitat
specific
 Driven by wave of
disturbance
Indigenous Species associated with parthenium
Species
Abutilon mauritianum
Acacia drepanolobium
Crotolaria labanifolia
Sphaeranthus ukambensis
Ipomoea spp.
Euphorbia hirta
Plectranthus hybridus
Sida odorata
Triumfetta flavascens
• Limited ethno botanical/
economic impact information
• Lists of species associated with
parthenium are basis for
ecological/biodiversity impact
studies)
Invasive Alien species associated with
parthenium
Amaranthus spp.
Opuntia ficus-indica
Cassia siamea
Cirsium vulgare
Nicotiana glauca
Datura spp.
Lantana camara
Ricinus communis
Sesbania sesban
Sida acuta
Tagetes minuta
Withania somnifera
Xanthiun pungens
Significant inventory of IAS in
Kenya, including voucher
specimens and IAS database
initiated
Basis for future management
and/or control program
Cumulative Data
analysis/interpretation
Parthenium hotspots
Corroborates Climex
prediction: Western, S.
Western Kenya, central
and Nairobi regions
NOT INVADED!
Coastal Kenya not yet
invaded
PATTERNS OF
DISTRIBUTION: 1
ALTITUDE
Lake Victoria Basin in
western Kenya
relatively low
Nairobi and Central
Kenya quite high
above sea level
Correlation with
altitude not obvious
PATTERNS OF
DISTRIBUTION 2: RAINFALL
Very high rainfall coincides
with very high altitude
Both Nairobi, Central and
Western Kenya receive
relatively high rainfall
Flooding rampant in the
Lake Victoria basin
Isolated occurrences in
semi arid localities (less than
500mm)
Correlation with relatively
high rainfall evident. Flooding
seems to be ideal for
dispersal
PATTERNS OF
DISTRIBUTION: 3
SOIL TYPES
Variable but
mostly clayey to
loamy
Some
Correlation with
type of soil
evident
PATTERNS OF
DISTRIBUTION 4:
URBANISATION and
associated
infrastructure
development:
In all survey areas,
higher densities of
parthenium were found
in towns and shopping
centres
Correlation with
urbanisation evident
Impact of parthenium dominance on Tourism
• Ecosystem stability and wildlife
diversity are core to tourism in
Kenya
– Nairobi National Park, Oldonyo
Sabuk, Mara GR and L. Nakuru
NP are already invaded
• Partheniumn suppresses natural
vegetation, replace dominant flora
in invaded habitats
• Has been reported to poison buffalo
bull calves in India
– reduced diversity of grazers and
dependent predators in
ecosystems will drastically
diminish visitor numbers
Impact of Parthenium on agro-ecosystems
Traditional bread basket is in danger
-Allelopathic inhibition reduces crop
yields
-Increased weeding
-Secondary host of crop pests
educed seed set due to heavy
deposition of parthenium pollen
Invaded crop field in Western Kenya
Impact of parthenium on human Health
• Toxic to humans & animals:
dermatitis & respiratory
allergies
• Human allergy problems
identified in Australia,
Ethiopia and India
• 73% of people living with
weed in Australia are
sensitive to it (women are
twice as sensitive)
 May lead to massive health
risks to people who earn a
leaving as casual labourers
due to intolerance to
allergies etc
Thoughts on status and future trends
Weed has two distinct
epicenters. Central Kenya
region is primary, western
Kenya is secondary
Has spread from original
points through movement of
people and vehicles
Heavy rains and flooding
increase danger of invasion
Outlier populations are
considered to be founder
populations and evidence of
future spread
Costal Kenya is a locality to
watch due to increased
construction of roads etc
Conclusions and recommendations
• Documentation accomplished in this research
is an important beginning for work on
management
• Lack of knowledge on potential impact of
parthenium dangerously predisposes Kenyan
populace to social-economic risks
• Need to consolidate knowledge of parthenium
regionally/globally and embark on tackling the
next level of action:-management
Acknowledgements