threatened fauna of the canterbury region colin f j o’donnell southern regional science centre...
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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