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Threatened fauna of the Canterbury Region Colin F J O’Donnell Southern Regional Science Centre Department of Conservation PO Box 13049, Christchurch Threatened fauna Terrestrial Birds mammals Critical 6 Endangered 1 6 Vulnerable 6 Serious 4 decline Gradual 9 decline Sparse 5 Range 1 restricted Total 1 37 Reptiles Freshwater Invertebrates Total fish 10 16 1 11 19 6 2 6 6 3 6 24 2 2 25 39 34 40 8 6 93 145 Proportion of national total in Canterbury - fauna taxa 35 25 20 15 10 5 ra te s ve rte b es hw Fr In at er fis h til es s Bi rd Re p am m al s 0 Te rr es tri al m Percentage 30 Wetlands/lowland rivers >90% drained Canterbury Mudfish • Aquatic vegetation/ overgrown springs and margins of wetlands • Can cope with short periods of drying – form burrows • Solitary N 0 40 km Lowland longjaw galaxias Kakanui (Kauru River) Hakataramea (1989) Twizel area (e.g. Fraser Stream) N 0 20 km Open braided cobble/gravel river Shallow riffle habitat ? Spawning requirements Threats 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 Braided rivers – Multiple channels – Flow instability – High gradients – High levels of sediment supply and movement – Constant channel movements – Seasonally rich food supplies These processes provide outstanding feeding and nesting habitat for wetland birds & other fauna an t W erb es ur tC y N el oas so n/ t So M a ut rl hl an d O H aw tag ke o s G B ay is bo W r el ne lin W gto a n B a ng y an ui of Pl e Ta nty ra na ki C hectares Distribution of braided rivers nationally 160000 140000 120000 163 rivers 100000 80000 60000 40000 20000 0 Number of wetland birds from index counts on rivers 25,000 > 80 bird species 20,000 15,000 10,000 5,000 As hb ur to n R As hl ive r ey H ur R un iv M ui ac er R ive ken zie rs & M ou O pi hi th Ri O ve ra r ri R R iv ak er a R ia an R i gi ta ver ta Ri W ve ai W a r ai u m ak Riv er ar iri W Ri a W ita ver ilb ki er fo Riv er rc e R iv er 0 O’Donnell & Moore (1983), Robertson et al. (1984), Maloney (1999) Trends in wrybill numbers 8000 7000 6000 5000 4000 3000 2000 1000 0 1965 1994 2001 Hay (1979), Davies (1997), Riegen & Dowding (2001) c.1900 1979 2007 Trends in wrybill numbers Edwards Stream – Scree Skink habitat Threats: weed encroachment Proportions of major rivers with weed encroachment 80 70 After Wilson (2001) 50 40 30 20 10 As hb ur to n O pi hi ey As hl ta an gi ta ak a R au W ai ia R ai m ak ar iri 0 W % weeds 60 Loss of water: Increased demand for irrigation water Loss of water: Each species has a different requirement Log mean flow Relationship of mean flow (log) to tern numbers 3 2.5 2 1.5 1 0.5 0 y = 0.237Ln(x) + 0.2929 2 R = 0.3836 0 500 1000 tern numbers 1500 Predation by introduced mammals The ‘moat’ effect – islands separated from the mainland by large flows appear to limit predation What can be done? Rules for habitat protection Firewood cutting rules Legal protection of waterways Adequate environmental flows to sustain fauna • Assured environmental flows and water levels in rivers/wetlands/coastal lagoons Protected areas networks • Focus on lowlands where >90% loss • For example: Protect a representative range of rivers – Braided rivers are not represented in our reserve network (though the waters of some are now protected with Conservation Orders) • Most riverbeds are classed as “unoccupied crown land” or are council/private land Known fates* Sustained predator control 10 9 8 7 6 5 4 3 2 1 0 Poison laid 80% dead within 2 days 1 3 5 7 9 11 13 15 Days since live trapping ended 17 19 Community conservation initiatives: bat houses in South Canterbury Species translocations: Quail Island using wooden disc technique for beetles… Recreation management Black-fronted tern chick crushed by vehicle Education Conclusions: Huge challenges • Most threatened biodiversity does NOT occur in reserves or on DOC land • Need good inventories of what still remains • Regional action plans (Canterbury Biodiversity Strategy first step) • Need to turn the strategy into action to halt the loss