Protecting indigenous biodiversity in the eastern South Island rainshadow zone

1. Protecting indigenous biodiversity in the eastern South Island rainshadow zone Susan Walker Lance McCaskill Memorial Lecture Forest & Bird North Canterbury Branch Annual General Meeting WEA, Christchurch 9 June 2010

2. Structure of my talk • South Island drylands: characteristics and challenges • Pre-settlement dryland ecology • Radiations and endemism • The rule and role of birds and reptiles • All but fire-free • 3. Humans and the transformation of ecosystems • Post-settlement period • Pastoral period • 4. Where to from here? • Four trends in drylands today • The case for a return to woody dominance • Retreating opportunities

3. Structure of my talk • South Island drylands: characteristics and challenges • Pre-settlement dryland ecology • Radiations and endemism • The rule and role of birds and reptiles • All but fire-free • 3. Humans and the transformation of ecosystems • Post-settlement period • Pastoral period • 4. Where to from here? • Four trends in drylands today • The case for a return to woody dominance • Retreating opportunities

4. New Zealand drylands East of main axial ranges Annual Penman Moisture Deficit >270 mm (monthly evaporation minus monthly rainfall, in mm, summed across 12 months) Area ~ 53,000 km2 (20% of NZ) http://www.doc.govt.nz/upload/documents/science-and-technical/SFC258.pdf

5. Canterbury’s drylands ENVIRONMENT TYPES Southern and inland environments G: Inland southern South Island basins and valley floors H: Mackenzie Basin and Central Otago hillslopes Northern and coastal environments B. Dry hill country (characteristic of North Island drylands, more widespread there) D. Coastal Marlborough and Kaikoura Coast low relief alluvium & loess E: Marlborough and North Canterbury hillslopes F: Canterbury Plains, Banks Peninsula and Otago inland basin alluvium and loess

6. South Island dryland ecosystems Characteristics Remaining native ecosystems and species are some of New Zealand’s most transformed, least protected and most threatened

7. Threat classification for land environments “THREATENED ENVIRONMENTS”

8. Canterbury dryland environments THREATENED ENVIRONMENTS

9. 60 40 20 0 Lowland Montane Subalpine & Alpine Canterbury Region (~2005) % LOSS of indigenous cover since European settlement, by elevation zone 100 80 % LOSS of indigenous cover in elevation zone 60 40 20 0 0 to 400m 400 to 800m 800 to 1200 to >1600 m 1200m 1600m Distribution of threatened plants Canterbury’s 103 Acutely and Chronically Threatened plants (2005 threat classification categories) No. of Acutely and Chronically Threatened plants

10. South Island dryland ecosystems Characteristics Remaining native ecosystems and species are some of New Zealand’s most transformed, least protected and most threatened Ecosystems are unstable (not at equilibrium) and much invaded

11. South Island dryland ecosystems Characteristics Remaining native ecosystems and species are some of New Zealand’s most transformed, least protected and most threatened Ecosystems are unstable (not at equilibrium) and much invaded Major conservation challenges Extremely low awareness of dryland biodiversity and its protection needs (community and agencies) Limited knowledge, experience and science to support management for biodiversity protection

12. Some of Canterbury’s dryland communities Kowhai Bush, Kaikoura Kanuka & mixed broadleaved forest and shrubland, with scattered podocarps

13. Rakaia Island communities Kanuka forest, kowhai remnants, dry shrubland

14. Riparian kowhai/lowland ribbonwood remnants, South Canterbury

15. South Canterbury shrubland and forest remnants Fierce lancewood Pseudopanax ferox Hector’s tree daisy Olearia hectori

16. Limestone communities, North Canterbury

17. Limestone communities, South Canterbury Gentianella calcis subsp. taiko

18. Mcleans Island grasslands

19. Birdlings Flat/ Lake Forsyth shrublands

20. South Branch Hurunui valley floors and gorge

21. Ashburton Basin floor grasslands, shrublands and wetlands

22. Mackenzie Basin foothills

23. Mackenzie Basin floors

24. Mackenzie Basin floor 23% of Canterbury’s ‘Threatened’ and ‘At Risk’ plants, and 11% of Canterbury’s ‘Data Deficient’ plants

25. Mackenzie Basin floor Threatened and At Risk flora 31 species Wetlands and their margins and turfs 33 species Grassland and shrublands

26. Mackenzie Basin floor Diverse, endemic, threatened invertebrates Moth, grasshopper and beetle faunas especially rich & distinctive

27. Canterbury’s drylands ENVIRONMENT TYPES Southern and inland environments G: Inland southern South Island basins and valley floors H: Mackenzie Basin and Central Otago hillslopes

28. Remaining opportunities for dryland biodiversity conservation Dryland Types 14000 Woody mixed native-exotic Grassy 12000 Intensively developed 10000 8000 Area (km2) 6000 4000 2000 0 A B C D E F G H Dryland type

29. Structure of my talk • South Island drylands: characteristics and challenges • Pre-settlement dryland ecology • Radiations and endemism • The rule and role of birds and reptiles • All but fire-free • 3. Humans and the transformation of ecosystems • Post-settlement period • Pastoral period • 4. Where to from here? • Four trends in drylands today • The case for a return to woody dominance • Retreating opportunities

30. Pleistocene Radiations and endemism • Likely drivers • Absence of forest • New habitats & vacant niches • Isolation ‘Permanent’ barriers (mountains, geological islands) Temporary barriers i.e. glaciations

31. Dryland radiations & endemism Native brooms Brachaspis grasshoppers “The species exhibit remarkable diversity, from trees to prostrate forms a few centimetres high” (Bevan Weir, NZ Rhizobia)

32. ‘Non-diadromous’ galaxiid fishes

33. Lowland longjaw Pencil galaxiids of the Mackenzie Basin Upland longjaw Bignose galaxiid

34. On land, birds and lizards ruled “No where else had birds evolved to become the ecological equivalent of giraffes, kangaroos, sheep, striped possums, long-beaked echidnas, and tigers” (Tim Flannery, The Future Eaters)

35. Mega-bird herbivory Diversity of moa sizes and feeding habits

36. Grazers Finschs duck Teal Takahe

37. Browsers

38. Tree munchers Pachyornis Olearia gizzard twigs Gizzard stones

39. Arboreal defoliators

40. Frugivores and seed dispersers

41. Frugivores and seed dispersers Lizards too!

42. Pollinators

43. Understorey scratchers and bashers

44. Turf-maintenance crews

45. Bird legacies in the flora Turfs

46. Bird defense mechanisms? Armoured Inpenetrable Inaccessible Unappetising (dead)

47. fleshy-fruited shrubs

48. and their imitators!

49. Big suite of endemic (non grass) herbs (many now threatened) No N-fixing herbs!

50. Pre-settlement ecosystems All but fire-free “... a bioclimatic zone, possibly unique on a global scale, which was dry, drought-prone but free of all but infrequent fire. The anomalous result is that New Zealand possesses a suite of shrubs and trees tolerant of dry, droughty conditions but highly sensitive to fire and slow to recover in its wake” (McGlone 2001, NZJ Ecol)