Threatened fauna of the Canterbury Region

Colin F J O’DonnellColin F J O’DonnellSouthern Regional Science Centre Southern Regional Science Centre

Department of ConservationDepartment of ConservationPO Box 13049, ChristchurchPO Box 13049, Christchurch

Threatened Threatened faunafauna

Terrestrial mammals

Birds Reptiles Freshwater fish

Invertebrates Total

Critical 6 10 16 Endangered 1 6 1 11 19 Vulnerable 6 6 Serious decline

4 2 6

Gradual decline

9 6 3 6 24

Sparse 5 2 2 25 34 Range restricted

1 39 40

Total 1 37 8 6 93 145

Proportion of national total in Proportion of national total in Canterbury - fauna taxaCanterbury - fauna taxa

0

5

10

15

20

25

30

35

Terre

stria

l mam

mals

Birds

Reptiles

Freshw

ater

fish

Inve

rtebra

tes

Per

cen

tag

e

Wetlands/lowland riversWetlands/lowland rivers

>90% drained>90% drained

Canterbury MudfishCanterbury Mudfish

0 40 km

N

• Aquatic vegetation/ overgrown springs and margins of wetlands

• Can cope with short periods of drying – form burrows

• Solitary

0 20 km

N

Lowland longjaw galaxiasLowland longjaw galaxias

Kakanui (Kauru River)Hakataramea (1989)Twizel area (e.g. Fraser Stream)

Open braided cobble/gravel riverShallow riffle habitat

? Spawning requirements

• Badly designed culverts, weirs, and dams

• Pollution and sedimentation

• Changes in water levels/drainage

• Stock damage to margins

• Predation & competition

• Loss of habitat

• Reduced flows

• Overfishing

• Weed encroachment

ThreatsThreats

Braided riversBraided rivers

– Multiple channels Multiple channels

– Flow instabilityFlow instability

– High gradientsHigh gradients

– High levels of sediment supply and High levels of sediment supply and movementmovement

– Constant channel movementsConstant channel movements– Seasonally rich food suppliesSeasonally rich food supplies

These processes provide outstanding These processes provide outstanding feeding and nesting habitat for feeding and nesting habitat for wetland birds & other faunawetland birds & other fauna

0

20000

40000

60000

80000

100000

120000

140000

160000

he

cta

res

Distribution of braided rivers Distribution of braided rivers nationallynationally

163 rivers

0

5,000

10,000

15,000

20,000

25,000

Ashbu

rton

River

Ashle

y Rive

r

Mac

kenz

ie

Hurun

ui Rive

rs &

Mou

th

Opih

i Rive

r

Ora

ri Rive

r

Rakai

a Rive

r

Rangit

ata

River

Wai

au R

iver

Wai

mak

ariri

River

Wai

taki

River

Wilb

erfo

rce R

iver

O’Donnell & Moore (1983), Robertson et al. (1984), Maloney (1999)

Number of wetland birds Number of wetland birds from index counts on riversfrom index counts on rivers

> 80 bird species

Trends in wrybill numbersTrends in wrybill numbers

0

1000

2000

3000

4000

5000

6000

7000

8000

1965 1994 2001

Hay (1979), Davies (1997), Riegen & Dowding (2001)

c.1900

1979

2007

Trends in wrybill numbersTrends in wrybill numbers

Edwards Stream – Edwards Stream – Scree Skink habitatScree Skink habitat

Threats: weed encroachmentThreats: weed encroachment

Proportions of major rivers with Proportions of major rivers with weed encroachmentweed encroachment

0

10

20

30

40

50

60

70

80

Waim

akar

iri

Waia

u

Rakaia

Rangit

ata

Ashley

Opihi

Ashbu

rton

% w

eed

s

After Wilson (2001)

Loss of water: Increased Loss of water: Increased demand for irrigation waterdemand for irrigation water

Loss of water: Loss of water: Each species has a different requirementEach species has a different requirement

Relationship of mean flow (log) to tern numbers

y = 0.237Ln(x) + 0.2929

R2 = 0.38360

0.51

1.52

2.53

0 500 1000 1500

tern numbers

Log

mea

n f

low

The ‘moat’ effect – islands separated The ‘moat’ effect – islands separated from the mainland by large flows appear from the mainland by large flows appear

to limit predationto limit predation

Predation by introduced mammalsPredation by introduced mammals

What can be done?What can be done?

Rules for habitat protectionRules for habitat protection

Legal protection of waterways

Firewood cutting rules

Adequate environmental Adequate environmental flows to sustain faunaflows to sustain fauna

• Assured environmental flows and water Assured environmental flows and water levels in rivers/wetlands/coastal lagoonslevels in rivers/wetlands/coastal lagoons

Protected areas networksProtected areas networks

• Focus on lowlands where >90% lossFocus on lowlands where >90% loss• For example: Protect a representative range of For example: Protect a representative range of

riversrivers– Braided rivers are not represented in our Braided rivers are not represented in our

reserve network (though the waters of some reserve network (though the waters of some are now protected with Conservation Orders)are now protected with Conservation Orders)

• Most riverbeds are classed as “unoccupied Most riverbeds are classed as “unoccupied crown land” or are council/private landcrown land” or are council/private land

Sustained predator control Sustained predator control

0123456789

10

1 3 5 7 9 11 13 15 17 19

Days since live trapping ended

Kn

ow

n f

ate

s*

Poison laid80% dead within 2 days

Community conservation Community conservation initiatives: initiatives: bat houses in South Canterbury

Species translocations:Species translocations: Quail Island using wooden disc technique for beetles…

Recreation Recreation managementmanagement

Black-fronted tern chick crushed by vehicle

EducationEducation

Conclusions: Conclusions: Huge challengesHuge challenges

• Most threatened biodiversity does NOT Most threatened biodiversity does NOT occur in reserves or on DOC landoccur in reserves or on DOC land

• Need good inventories of what still remainsNeed good inventories of what still remains

• Regional action plans (Canterbury Regional action plans (Canterbury Biodiversity Strategy first step)Biodiversity Strategy first step)

• Need to turn the strategy into action to halt Need to turn the strategy into action to halt the lossthe loss