Transcript Designing & Planning sustainable habitat configurations in

Designing & Planning
Sustainable Habitat
Configurations
in New Zealand’s Cultural
Landscapes
Colin Meurk & Graeme Hall
[email protected]
NZ landscape at a crossroads –
which way the countryside?
• Similar development of cultural landscape to
England …
• But 5000 years crammed into <1000! … &
• No equivalent latterday integration of nature,
culture & production in NZ – or not yet!
• We may carry on along the present trajectory …
• or redirect landscape evolution towards preserving
NZ’s special identity thru biodiversity & natural
character
Worse than europe because …
• Shade-tolerant invaders take over …
• Little native regen. after pressure removed
• Small native herbs swamped by exotic grass
• Seedbanks dominated by exotic spp.
Visibility
of nature
•Human memory banks dominated by exotics
Sustainable Management & Use
of natural resources
Identification
with regional biodiversity
& landscape
Protectiveness
towards natural values
Landscape &
Ecological
Sustainability &
Integrity Feedback
System
Learning
from natural processes
Enculturation
of natural values
Quality of Life
definition
Familiarity
with nature
Love it or Lose it!
• Habitat loss accelerated Post-RMA –
nonsense!
• Insulting - community restoration efforts
overwhelmed by govt & corporate destruction
• Diversionary tactics – huge numbers of
strategies, policies & rules gathering dust!
• Is it to be a Knowledge Economy or a Dark
Ages of trivia, waste, sterility, lost identity, life
denial?
If Serious … Need to know …
• What is likely to happen?
• What innovative intervention is possible/necessary to
achieve goals of natural character in the NZ landscape?
• No longer are we divorced from our role as ‘intelligent’
conductors of landscape form & direction
• If we don’t provide leadership then someone else will
prescribe our landscape & culture for us!
• In this presentation we provide some positive options &
guidelines for overcoming the gloomy prognosis for NZ’s
biodiversity & landscapes
Start with Forest succession
model adapted from US Linkages
(Pastor & Post 1985)
• Reformulated & generalised as LINKNZ (Hall
& Hollinger 2000)
• Empirically based & tested models
(Fiordland, SE NZ pollen, Lake Thompson,
Pisa Range, NZ Biomes)
• Operates on autecological, physiological &
growth properties of trees in relation to
climate & soil conditions of a site
Bringing in the Spatial
Component
Successful Propagule
Dispersal
Linking
succession &
dispersal
Composite scenarios
• In fullness of time – distance makes little
difference …
• Provided there are receptive habitats & …
• Pest control …
• Kauri or podocarps come to dominate in
lowlands – regardless of starting line up
(native or exotic).
• In contrast, the montane zone, where native
beech forests predominate, is in trouble from
exotic shade-tolerant invaders
Native Plant Colonisation of Receptive Habitats
in Cultural Landscapes
Applying models to green space
planning
• Link with island biogeographic approach to reserve
design
• Bigger is always better, but …
• In constrained environments (urban & rural) ..
• Have to make compromises …
• In general, large iconic bush birds – kiwi, kokako need remnants >> 6 ha
• But, most NZ wildlife is either small (1-6 ha adequate
for viable populations) or vagile, so can …
• Use stepping stones in a patchy landscape
Combining reserve design,
dispersal data, stepping stones &
visibility/accessibility
• 6.25, 1.6 & 0.01 ha forest patches with 50 m buffer
have …
• 2.25, 0.06 & 0.0 ha core respectively
• These should be maximally 5, 2 & 0.02 km apart from
patches of their own or larger size
• Such an optimum configuration for forest patches in a
cultural landscape – allows …
• Propagule saturation across whole landscape
• Bird habitat virtual continuity
• Gene flow between plant & animal populations
Optimising Patch Shape – Linear forest patch
625 m
50 m buffer
zone
100 m
core area = zero ha
Street/playground
Noble Tree Grove
total area = 6.25 ha
Neighbourhood
Habitat Patch
125 m
10 m
District/Suburb
Core Sanctuary
250 m
150 m
10 m
25 m
0.01 ha
125 m
25 m
core
2.25 ha
Core
0.06 ha
Total area
1.56 ha
Buffer
zone
Total area 6.25 ha
skin
150
m
250
m
Optimal Forest Patch Pattern & Percentage Patch Area Calculation
60°
1/6 of 6.25 ha
patch
4.33 km
60°
60°
5 km
Percentage Patch Area Calculation
Thus 3/6 of patch size in whole triangular area
for 6.25 ha at 5 km spacings –
Area = ½ x 5 x 4.33 km2
x 100 ha
= 1082.5 ha
% area occupied by large patches
= 6.25 x 3/6 x 100%
1082.5
= 0.29%
Total patch area = ca. 4.4%
6.25 ha
1 km
0.2 km
0.01 ha
Urban
matrix
1.56 ha
5 km
Frequent
dispersal
Integrating People
Nature &
Landscape
100 m
100 m
Clusters of big trees every 200 m
1 km
1 km
500 m
5-10 min walk
1 ha reserve every km;
5 minutes walk from every home
Observed max.
dispersal
2.5 km
10 mins
cycling
4-10 ha reserve every 5 km;
30 minutes walk/
10 minutes cycling from every home
The real world of green space
planning in SW Christchurch
Opportunities …
• Plight of NZ biota & Biodiversity Strategy
cries out for drastic measures – at a broad
landscape level
• Positive signs in spontaneous regen. of some
native elements
• Can manipulate & redirect this dynamic – so
long as we stop throwing around time bombs
(weeds)
• Models test novel ideas about where the
biosecurity threats lie in the long term …&
how to …
• transform exotic plantations into native
production systems (for utility & biodiversity)
Exotic to Podocarp
Plantation - Auckland
Biodiverse Landscapes Are Us!
• The following visualisations are backed by
the data & models presented here
• We have to be very patient tho …
• may take centuries to restore the landscape
- equivalent to the idyll of the english
countryside
• But if we don’t start now (by preserving the
primary habitats or building blocks) the
potential will be lost & the goal will be out of
reach.
Contemporary Dysfunctional Rural
Landscape
Prospective Integrated Functional
Landscape
Contemporary utilitarian high country landscape
remnant
native veg in
far distance
exotic plantation
retirement fence
lake
winter
wet
paddock
protected
natural
area
Moraine
with wilding
birch, briar,
etc
drain
Biodiverse high country futures
remnant
native veg,
regenerating
grazed
matagouri
woodland
retirement fence
boundary
obscured
exotic plantation
surrounded by nz trees
beech
Homestead
(opportunity
for native
rockeries)
native
hedgerows
shelter
belt with
native
border of
shrubs
short
tussock
lake
protected
natural
area
wetland
highway
hay bales
behind
native
hedgerows
Moraine with
native shrubs
& woodland
Stream with
riparian vegetation
Urban Bio-sterility?
Traditional urban conservation of
remnants or islands
The Native Bush Garden
‘Gardening’ for vulnerable herbaceous
biodiversity & wildlife
Recommendations – simple really
• No more rotations of Douglas fir in high country (estimate
200-250 years for saturation of entire montane beech
forest biome)
• Research & implement use of sterile pines or hybrids (e.g.
Leyland cypress) for forestry
• Promote new indigenous forestry by planting &
manipulating succession
• Get serious about weed control
• Promote/facilitate native regeneration in range of semiproduction & border habitats (hedgerows, woodlots, road
verges, riparian zones, homestead woods)
• Restore habitats – as last resort after protection of primary
habitat & land surfaces
• Integrate biodiversity into urban habitats
• Work at landscape/visible level (visibility is key to nature
sustainability)
• Generate scenarios as goals - incorporating traditional
structural elements & indigenous composition
Visibility is a key to sustainability –
don’t subjugate the Kiwi Identity to …