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)