Transcript Slide 1

Biodiversity in Canterbury
(with an emphasis on flora)
state, pressures, issues, and needs
Susan Walker
Landcare Research, Dunedin
ECan Land Workshop 22 April 2008
Council Chambers, Environment Canterbury
State
Large variation from upland to lowland
indigenous habitats retained, and protected, are “non
representative”
Canterbury habitats - habitat loss to 2001/02
Elevation zones
Remaining indigenous cover
<400 m
400 – 800 m
800-1200 m
1200-1600 m
>1600 m
Canterbury habitats - protection against loss
Protected lands
Elevation zones
<400 m
400 – 800 m
800-1200 m
1200-1600 m
>1600 m
Private covenant
or public
conservation
land
State
Large variation from upland to lowland
indigenous habitats retained, and protected, are “non
representative”
Remaining lowland ecosystems much reduced, highly
modified and poorly protected
Habitat loss : some science
Area effects
Proportion of species remaining
1) The relationship between area and proportion
of species remaining is not linear
2) The relationship is a curve
3) As area decreases, at some
point the proportion of species
decreases rapidly
0
0.2
0.4
0.6
0.8
Proportion habitat area remaining
1.0
Proportion of species remaining
An intact
environment
0
0.2
0.4
0.6
0.8
Proportion habitat area remaining
1.0
Proportion of species remaining
3.9%
PREDICTED
SPECIES
LOSS
An intact
environment
HABITAT
LOSS
10%
0
0.2
0.4
0.6
0.8
Proportion habitat area remaining
1.0
Proportion of species remaining
A modified environment
0
0.2
0.4
0.6
0.8
Proportion habitat area remaining
1.0
Proportion of species remaining
PREDICTED
SPECIES
LOSS
12%
A modified environment
HABITAT
LOSS
10%
0
0.2
0.4
0.6
0.8
Proportion habitat area remaining
1.0
Canterbury habitats - habitat loss to 2001/02
Elevation zones
Remaining indigenous cover
<400 m
400 – 800 m
800-1200 m
1200-1600 m
>1600 m
Canterbury habitats - habitat loss to 2001/02
>1200 m
Proportion of species remaining
800-1200 m
400-800 m
(37%)
Below
400 m
(7.5%)
0
0.2
0.4
0.6
0.8
Proportion habitat area remaining
1.0
Canterbury habitats - protection against loss
Protected lands
Elevation zones
<400 m
400 – 800 m
800-1200 m
1200-1600 m
>1600 m
Private covenant
or public
conservation
land
Proportion of species remaining
Canterbury habitats - protection against loss
>1600 m
1200-1600 m
800-1200 m
400-800 m
(11.5%)
Below
400 m
(1%)
0
20
40
60
80
Percent (%) of zone protected (Private Covenants or DOC)
100
Canterbury habitats - habitat loss to 2001/02
>1200 m
Proportion of species remaining
800-1200 m
400-800 m
(37%)
Below
400 m
(7.5%)
0
0.2
0.4
0.6
0.8
Proportion habitat area remaining
1.0
Proportion of species remaining
Canterbury habitats - protection against loss
>1600 m
1200-1600 m
800-1200 m
400-800 m
(11.5%)
Below
400 m
(1%)
0
20
40
60
80
Percent (%) of zone protected (Private Covenants or DOC)
100
Fragmentation
Habitat loss
Habitat remaining
Below about 30%
area remaining,
patch isolation
increases
exponentially
(simulation,
supported by review
of field study results)
Simulated distance to nearest neighbour
Isolation effects
10
Average distance
8
Maximum distance
Std dev.
6
No. habitat patches
4
(Andrén 1994)
2
0
0
20
40
60
80
100
Proportion of original habitat in the landscape (%)
Nationally threatened plants in
Canterbury
Proportion of NZ land area
Proportion of NZ
Threatened plants (2005)
(Acutely and Chronically
Threatened)
Canterbury
Canterbury
(47%)
103 species
Distribution of threatened plants in Canterbury (2005)
By elevation zone
No. Acutely and
Chronically
Threatened plants
60
40
20
0
“Lowland”
30
“Montane”
“Subalpine & Alpine”
By ecosystem type
No. Acutely and
Chronically
Threatened plants
25
20
15
10
5
0
Wetland Limestone Grassland Shrubland
Forest
Coast
Bluff
Scree
Also locally or regionally threatened:
‘common’ palatable or fire sensitive trees and shrubs
Hebe cupressoides
Tekapo military camp
In other places, more rugged secondary woody
species and communities are expanding
State – to sum up
Large variation from upland to lowland
indigenous habitats retained, and protected, are “non
representative”
Remaining lowland ecosystems much reduced, highly
modified and poorly protected
High numbers of threatened plant species, particularly
•
in the lowland and montane zones (which are poorly
protected)
•
in highly modified, non-forest ecosystems
Woody vegetation in flux: some winners, some losers
Threatened Environment
Classification
For each LENZ Level IV environment,
the classification shows
how much indigenous cover
remains & how much is protected
LENZ
Canterbury
% Indigenous
cover left
% Protected
+
Threatened Environment Classification
+
=
Habitat loss and poor protection:
indicators of threatened plant distribution in Canterbury
% indigenous cover left
100
80
80
60
60
40
40
20
20
0
0
0 to 400m
400 to 800m
800 to
1200m
1200 to
1600m
>1600 m
% protected
(Private covenants or DOC)
0 to 400m
400 to 800m
800 to
1200m
Distribution of Canterbury threatened plants (2005)
60
No. Acutely and
Chronically
Threatened plants
Percenatge area
100
40
20
0
“Lowland”
“Montane”
“Subalpine & Alpine”
1200 to
1600m
>1600 m
Threatened environments:
Correlated with threatened plants in covenants
Threatened Species in South Island QEII covenants
Number of threatened plant species
17 geographically widespread covenants (Nelson, Marlborough, Canterbury,
Otago & Southland)
10
9
8
7
1
2
3
4
5
6
6
5
4
3
2
1
0
1
2
3
4
5
6
Thanks to Wildlands,
esp. Kelvin Lloyd
Canterbury’s Threatened Environments
<10%
indigenous
cover left
(24%)
23%
1.3 million ha
(31%)
New Zealand
Canterbury
Environment Threat Categories
(Proportion Land Area)
Categories 1, 2 & 3
• Environments with much reduced indigenous
vegetation
•
•
•
•
Loss of habitats for native species has been greatest
Communities are often highly modified and depleted
Often provide critical habitat for threatened species
NOTE: Categories 1 & 2 are National Priority 1 in the
government’s National priorities for protecting rare &
threatened native biodiversity on private land
1
<10% indigenous cover left
Acutely Threatened
2
10–20% left
Chronically Threatened
3
20–30% left
At Risk
Birdlings Flat,
Canterbury
<10% indigenous cover left
(Acutely Threatened)
Rakaia Island kanuka forest &
<10% indigenous cover left
(Acutely Threatened)
River engineering work to protect kanuka forest
and dry shrubland at Rakaia Island
Relict kowhai/Plagianthus
woodland, South Canterbury
<10% indigenous cover left
(Acutely Threatened)
Mcleans Island
<10% indigenous cover left
(Acutely Threatened)
Weka Pass area
North Canterbury
<10% indigenous cover left
(Acutely Threatened)
Limestone Valley
South Canterbury
<10% indigenous cover left
(Acutely Threatened)
Gentianella calcis subsp. taiko
South Canterbury
<10% indigenous cover left
(Acutely Threatened)
Olearia hectori
Aciphylla subflabellata
Pseudopanax ferox
Kowhai Bush, Kaikoura
10-20% indigenous cover left
(Chronically Threatened)
Banks Peninsula Crater Rim
20-30% indigenous cover left
(At Risk)
Ashburton Basin
20-30% indigenous
cover left
(At Risk)
Categories 4 & 5
• Environments with poorly protected indigenous biodiversity
• Loss of habitats for native sp has been less extreme (>30%
indigenous cover left), BUT
• Poorly protected (<20% of land area)
• Often highly modified and depleted
• Poorly protected indigenous vegetation may be vulnerable to
development, and may receive little conservation management
(pest, weed control)
• Species are more likely to be in decline or at risk of extinction
than in better protected environments
4
>30% left and 10% protected
Critically Underprotected
5
>30% left and 10–20% protected
Underprotected
Mackenzie Basin
>30% left and <10% protected
Critically Underprotected
Mackenzie Basin
>30% left and <10% protected
Critically Underprotected
Category 6
• Environments with less reduced and better
protected indigenous biodiversity
• In past these environments have been less suitable for
development, therefore more secure to clearance
• Particularly important for species that require extensive
habitats to survive
• Many threatened animals (birds, bats, fish, frogs) now
survive only here
• BUT Still vulnerable to pest, weeds, other extractive land-use
(mining, logging, hydro development)
6
>30% left and >20% protected
Less Reduced and
Better Protected
Shrubland
Lake Coleridge
>30% left and >20% protected
(Less Reduced Better
Protected)
Forest and scree, Arthurs
Pass
>30% left and >20% protected
(Less Reduced Better
Protected)
Pressures on native flora
Herbivory
•Not only stock…
•Ubiquitous feral grazers
and browsers
Pressures on native flora
Herbivory
Weeds
•Light-demanding, grazing tolerant
weeds
•Persistent tall woody weeds
But some seral
woody “weeds” are
1) natives and/or
2) may provide
nurses for native
plants and/or shelter
and food for native
animals
Removing them
could do biodiversity
more harm than good
Pressures on native flora
Herbivory
Weeds
Incompatible activities
Irrigation
Use of spray (and fire) to clear ‘scrub’
Pressures on native flora
Herbivory
Weeds
Incompatible activities
Rapid habitat loss to land use intensification
Mackenzie Basin
Ashburton Basin
Issues (my thoughts)
The regional council has a major role
Community awareness and support is critical
BUT: Economics tells us voluntary approaches cannot solve the
problem!
Much to do on many fronts, few tools to help prioritise
Biodiversity
persistence
=
Conservation of
pattern + process
(The desired outcome)
Biodiversity
protection
in Canterbury
(Councils, DOC,
LINZ, landowners,
community
groups, etc)
1. Leave it
there
2. Legal
protection
3. Intervene
4. Restore
Biodiversity
persistence
Biodiversity
protection
in Canterbury
(Councils, DOC,
LINZ, landowners,
community
groups, etc)
=
Conservation of
pattern + process
Some
prioritisation and Much more difficult,
but some
reporting tools
emerging tools
ready to use now
(e.g. Pestspread)
Issues (my thoughts)
The regional council has a major role
Community awareness and support is critical
BUT: Economics tells us voluntary approaches cannot solve the
problem!
Much to do on many fronts, few tools to help prioritise
Good-news-only reporting is unlikely to help (Cullen,
Hughey et al.)
Capability and funding issues, esp. for smaller, poorer
councils
Needs (if you want to sustain biodiversity)
A bottom line
Need to cap indigenous vegetation loss
Indigenous vegetation needs to be defined broadly
Invest in an aware constituency
-
Work with willing landowners
Inform, advise, educate, incentivise, participate in activities
Monitor and report losses as well as gains
Build in-house biodiversity capability, and
relationships with district council biodiversity staff