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Threatened fauna of the Canterbury Region

Threatened fauna of the Canterbury Region. Colin F J O’Donnell Southern Regional Science Centre Department of Conservation PO Box 13049, Christchurch. Threatened fauna. Proportion of national total in Canterbury - fauna taxa. Wetlands/lowland rivers. >90% drained. Canterbury Mudfish.

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Threatened fauna of the Canterbury Region

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  1. Threatened fauna of the Canterbury Region Colin F J O’Donnell Southern Regional Science Centre Department of Conservation PO Box 13049, Christchurch

  2. Threatened fauna

  3. Proportion of national total in Canterbury - fauna taxa

  4. Wetlands/lowland rivers >90% drained

  5. Canterbury Mudfish • Aquatic vegetation/ overgrown springs and margins of wetlands • Can cope with short periods of drying – form burrows • Solitary

  6. Lowland longjaw galaxias Kakanui (Kauru River) Hakataramea (1989) Twizel area (e.g. Fraser Stream) Open braided cobble/gravel river Shallow riffle habitat ? Spawning requirements

  7. 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

  8. Braided rivers

  9. 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

  10. Distribution of braided rivers nationally 163 rivers

  11. Number of wetland birds from index counts on rivers > 80 bird species O’Donnell & Moore (1983), Robertson et al. (1984), Maloney (1999)

  12. Trends in wrybill numbers Hay (1979), Davies (1997), Riegen & Dowding (2001)

  13. c.1900

  14. 1979

  15. 2007

  16. Trends in wrybill numbers

  17. Edwards Stream – Scree Skink habitat

  18. Threats: weed encroachment

  19. Proportions of major rivers with weed encroachment After Wilson (2001)

  20. Loss of water: Increased demand for irrigation water

  21. Loss of water: Each species has a different requirement

  22. Predation by introduced mammals The ‘moat’ effect – islands separated from the mainland by large flows appear to limit predation

  23. What can be done?

  24. Rules for habitat protection Firewood cutting rules Legal protection of waterways

  25. Adequate environmental flows to sustain fauna • Assured environmental flows and water levels in rivers/wetlands/coastal lagoons

  26. 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

  27. Sustained predator control Poison laid 80% dead within 2 days

  28. Community conservation initiatives: bat houses in South Canterbury

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

  30. Recreation management Black-fronted tern chick crushed by vehicle

  31. Education

  32. 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

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