Biodiversity in Canterbury (with an emphasis on flora) state, pressures, issues, and needs Susan...
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Transcript of Biodiversity in Canterbury (with an emphasis on flora) state, pressures, issues, and needs Susan...
Biodiversity in Canterbury (with an emphasis on flora)
state, pressures, issues, and needs
Susan WalkerLandcare Research, Dunedin
ECan Land Workshop 22 April 2008
Council Chambers, Environment Canterbury
Large variation from upland to lowlandindigenous habitats retained, and protected, are “non representative”
State
Canterbury habitats - habitat loss to 2001/02
Elevation zones Remaining indigenous cover
<400 m400 – 800 m800-1200 m1200-1600 m>1600 m
Elevation zones
<400 m400 – 800 m800-1200 m1200-1600 m>1600 m
Protected lands
Private covenant or public conservation land
Canterbury habitats - protection against loss
Large variation from upland to lowlandindigenous habitats retained, and protected, are “non representative”
Remaining lowland ecosystems much reduced, highly modified and poorly protected
State
1.00.4 0.6 0.80 0.2
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
Habitat loss : some scienceArea effects
Pro
po
rtio
n o
f sp
ecie
s re
mai
nin
g
Proportion habitat area remaining
1.00.4 0.6 0.80 0.2
An intact environment
Pro
po
rtio
n o
f sp
ecie
s re
mai
nin
g
Proportion habitat area remaining
1.00.4 0.6 0.80 0.2
An intact environment
3.9%
10%
HABITAT LOSS
PREDICTEDSPECIES
LOSS
Pro
po
rtio
n o
f sp
ecie
s re
mai
nin
g
Proportion habitat area remaining
1.00.4 0.6 0.80 0.2
A modified environment
Pro
po
rtio
n o
f sp
ecie
s re
mai
nin
g
Proportion habitat area remaining
A modified environment
1.00.4 0.6 0.80 0.2
10%
HABITAT LOSS
PREDICTEDSPECIES
LOSS
12%
Pro
po
rtio
n o
f sp
ecie
s re
mai
nin
g
Proportion habitat area remaining
Canterbury habitats - habitat loss to 2001/02
Elevation zones Remaining indigenous cover
<400 m400 – 800 m800-1200 m1200-1600 m>1600 m
1.00.4 0.6 0.80 0.2
800-1200 m
Below400 m(7.5%)
400-800 m (37%)
>1200 m
Canterbury habitats - habitat loss to 2001/02P
rop
ort
ion
of
spec
ies
rem
ain
ing
Proportion habitat area remaining
Elevation zones
<400 m400 – 800 m800-1200 m1200-1600 m>1600 m
Protected lands
Private covenant or public conservation land
Canterbury habitats - protection against loss
10040 60 800 20
Percent (%) of zone protected (Private Covenants or DOC)
400-800 m(11.5%)
Below400 m(1%)
1200-1600 m
Canterbury habitats - protection against loss
>1600 m
800-1200 m
Pro
po
rtio
n o
f sp
ecie
s re
mai
nin
g
1.00.4 0.6 0.80 0.2
800-1200 m
Below400 m(7.5%)
400-800 m (37%)
>1200 m
Canterbury habitats - habitat loss to 2001/02P
rop
ort
ion
of
spec
ies
rem
ain
ing
Proportion habitat area remaining
10040 60 800 20
Percent (%) of zone protected (Private Covenants or DOC)
400-800 m(11.5%)
Below400 m(1%)
1200-1600 m
Canterbury habitats - protection against loss
>1600 m
Pro
po
rtio
n o
f sp
ecie
s re
mai
nin
g
800-1200 m
Below about 30% area remaining, patch isolation increases exponentially (simulation, supported by review of field study results)
(1)
(1)
(12)
(75)
(255
)
(739
)(1
089)(1
297)(1
242)
(802
)
(443
)
(193
)
0
2
4
6
8
10
0 20 40 60 80 100 Proportion of original habitat in the landscape (%)
Sim
ula
ted
dis
tan
ce
to
ne
are
st
ne
igh
bo
ur
(Andrén 1994)
Average distance
Maximum distance
Std dev.
(n) No. habitat patches
Habitat remainingHabitat loss
Isolation effects
Fragmentation
Canterbury
Proportion of NZ Threatened plants (2005)
(Acutely and Chronically Threatened)
Proportion of NZ land area
Canterbury
(47%)
103 species
Nationally threatened plants in Canterbury
Distribution of threatened plants in Canterbury (2005)By elevation zone
No
. Acu
tely
an
d
Ch
ron
ical
ly
Th
reat
ened
pla
nts
“Lowland” “Montane” “Subalpine & Alpine”
0
20
40
60
By ecosystem type
No
. Acu
tely
an
d
Ch
ron
ical
ly
Th
reat
ened
pla
nts
0
5
10
15
20
25
30
Wetland Limestone Grassland Shrubland Forest Coast Bluff Scree
Also locally or regionally threatened:‘common’ palatable or fire sensitive trees and shrubs
Hebe cupressoidesTekapo military camp
In other places, more rugged secondary woody species and communities are expanding
Large variation from upland to lowlandindigenous 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
State – to sum up
Threatened Environment
ClassificationFor each LENZ Level IV environment, the classification shows how much indigenous cover remains & how much is protected
% Indigenouscover left
+
LENZ
% Protected
+=
Threatened Environment Classification
Canterbury
0
20
40
60
80
100
0 to 400m 400 to 800m 800 to1200m
1200 to1600m
>1600 m
Habitat loss and poor protection: indicators of threatened plant distribution in Canterbury
0
20
40
60
80
100
0 to 400m 400 to 800m 800 to1200m
1200 to1600m
>1600 m
% protected (Private covenants or DOC)
% indigenous cover left
Per
cen
atg
e ar
ea
Distribution of Canterbury threatened plants (2005)
No
. Acu
tely
an
d
Ch
ron
ical
ly
Th
reat
ened
pla
nts
“Lowland” “Montane” “Subalpine & Alpine”
0
20
40
60
Threatened Species in South Island QEII covenants
Nu
mb
er o
f th
rea
ten
ed
pla
nt
sp
eci
es
123456
0
1
2
3
4
5
6
7
8
9
10
1 2 3 4 5 6
17 geographically widespread covenants (Nelson, Marlborough, Canterbury, Otago & Southland)
Threatened environments: Correlated with threatened plants in covenants
Thanks to Wildlands, esp. Kelvin Lloyd
Environment Threat Categories (Proportion Land Area)
Canterbury New Zealand
Canterbury’s Threatened Environments
23%
<10% indigenous cover left(24%)
1.3 million ha (31%)
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 forestand 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 areaNorth Canterbury
<10% indigenous cover left (Acutely Threatened)
Limestone ValleySouth Canterbury
<10% indigenous cover left (Acutely Threatened)
Gentianella calcis subsp. taiko
Olearia hectori
Aciphylla subflabellata
Pseudopanax ferox
South Canterbury <10% indigenous cover left
(Acutely Threatened)
Kowhai Bush, Kaikoura 10-20% indigenous cover left
(Chronically Threatened)
Banks Peninsula Crater Rim20-30% indigenous cover left
(At Risk)
Ashburton Basin20-30% 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
ShrublandLake Coleridge
>30% left and >20% protected(Less Reduced Better
Protected)
Forest and scree, Arthurs Pass
>30% left and >20% protected(Less Reduced Better
Protected)
Herbivory
Pressures on native flora
•Not only stock…
•Ubiquitous feral grazers and browsers
Herbivory
Weeds
Pressures on native flora
•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
Herbivory
Weeds
Incompatible activities
Pressures on native flora
Irrigation
Use of spray (and fire) to clear ‘scrub’
Herbivory
Weeds
Incompatible activities
Rapid habitat loss to land use intensification
Pressures on native flora
Mackenzie Basin
Ashburton Basin
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
Issues (my thoughts)
Biodiversitypersistence =
Conservation ofpattern + process
(The desired outcome)
1. Leave it there
Biodiversityprotection
in Canterbury(Councils, DOC,
LINZ, landowners, community groups, etc)
2. Legal protection
3. Intervene
4. Restore
Much more difficult, but some
emerging tools (e.g. Pestspread)
Some prioritisation and
reporting tools ready to use now
Biodiversitypersistence =
Conservation ofpattern + process
Biodiversityprotection
in Canterbury(Councils, DOC,
LINZ, landowners, community
groups, etc)
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
Issues (my thoughts)
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
Needs (if you want to sustain biodiversity)