Tenure review, land management, & protecting the biodiversity of the Mackenzie Basin floor

1. Tenure review, land management, & protecting the biodiversity of the Mackenzie Basin floor Susan Walker Talk prepared for the Canterbury Aoraki Conservation Board Canterbury Conservancy Office, 195 Hereford Street, Christchurch Thursday 2 September 2010

2. Thanks! Information, data, and photographs Richard Allibone, David Barrell, Warren Chinn, Joy Comrie, Marcus Davis, Nick Head, Bill Lee, Di Lucas, Ian Lynn, Colin Meurk, Geoff Rogers, James Shepherd, Ines Stager, Anne Steven, Marta Treskonova, Emily Weeks, Jamie Wood ‘Above Hawkes Bay’ (www.abovehawkesbay.com) and Geoff Rogers for oblique aerial photographs

3. Parts of this talk Part 1. Tenure review: a recap My past research and newer data Part 2. The Mackenzie Basin floor Environment, evolution and native biodiversity traits Changes and threats Part 3. Biodiversity protection and management Key ecological questions for protection proposals Changes under conservation management

4. Part 1. Tenure review: a recap

5. Walker, Price & Stephens 2008 • Assessed patterns of protection or privatisation to May 2005 • Predicted future protection and clearance (likelihood of loss) • Data sources • Land environments • Land cover (assumed binary indigenous/non-indigenous status for cover classes) • Frame: a continuous index of risk to biodiversity, based on the same principles as threatened environments

6. All land allocated in Tenure Review May 2005 66 leases since 1992 328,350 ha affected May 2005 66 leases since 1992 328,350 ha affected 1% retained as Special Lease 1% retained as Special Lease 5% privatised with a covenant 5% privatised with a covenant 39% protected (DOC) 39% protected (DOC) 55% privatised without a covenant 55% privatised without a covenant

7. Threat classification for land environments “THREATENED ENVIRONMENTS”

8. Threat classification for land environments More developable land, more threatened and less well-protected biodiversity • Assumptions • Risk to indigenous biodiversity is highest in land environments where habitats for native species • have been much reduced in the past and /or • are poorly protected today

9. Categorical spatial model of risk to biodiversity (Threatened Environment Classification) Original pastoral leases

10. Richmond Pastoral Lease Lake Tekapo

11. Richmond Pastoral Lease LEGALLY PROTECTED Lake Tekapo PRIVATISED

12. Braeside Pastoral Lease Hawkdun Range Upper Manuherikia Valley

13. LEGALLY PROTECTED PRIVATISED Braeside Pastoral Lease Hawkdun Range Upper Manuherikia Valley

14. Lowprobability of protection High probability of protection modeled % of indigenous cover protected as public land actual % indigenous cover remaining in environmentsHigh Risk << >> Low Risk From: Walker, Price & Stephens 2008

15. Leases have retained more indigenous cover than private land Pastoral leases Private land % privatisation loss 0-20% 20-40% 40-60% 60-80% 80-100% % indigenous cover remaining in environmentsHigh Risk << >> Low Risk

16. Average % of remaining indigenous cover predicted to be cleared following privatisation % post-privatisation clearance of remaining indigenous cover other % indigenous cover remaining in environmentsHigh Risk << >> Low Risk

17. Rogers & Reynolds (DOC unpublished data) Assessed patterns of protection or privatisation to September 2007 (i.e. 2 more years)

18. May 2005 66 leases since 1992 328,350 ha affected May 2005 66 leases since 1992 328,350 ha affected 1% retained as Special Lease 1% retained as Special Lease 5% privatised with a covenant 5% privatised with a covenant 39% protected (DOC) 39% protected (DOC) 55% privatised without a covenant 55% privatised without a covenant All land allocated in Tenure Review September 2007 90 leases since 1992 490,500 ha affected 6% privatised with a covenant Grazing (8%) 43% protected (DOC) 50% privatised without a covenant

19. Lowprobability of protection High probability of protection modeled (prediction) % of indigenous cover protected as public land actual % indigenous cover remaining in environmentsHigh Risk << >> Low Risk From: Walker, Price & Stephens 2008

20. Lowprobability of protection High probability of protection Predicted based on (66 leases to May 2005) % of indigenous cover protected as public land Actual (90 leases to September 2007) % indigenous cover remaining in environmentsHigh Risk << >> Low Risk

21. DOC recommended for protection as public land 100 90 80 70 60 50 40 30 20 10 0 Recommendations and achievements for significant inherent values in Tenure Review to Sept. 2007 LINZ achieved protection as public land More developable land More threatened biodiversity % of identified significant inherent values Threat categories from the Threatened Environment Classification (Walker et al. 2007) Data source: Department of Conservation, unpublished data for 69 of the 90 leases reviewed 1992-2007

22. Lowprobability of protection High probability of protection modeled (to May 2005) % of indigenous cover protected as public land % protection including private covenants % indigenous cover remaining in environmentsHigh Risk << >> Low Risk

23. Part 2. The Mackenzie Basin floor Environment, evolution and native biodiversity traits Changes and threats, old and new

24. 'Foothills' environments (Lenz Level I E) (mainly moriane landforms) 'Plains' environments (Lenz Level I N) (much reworked outwash) The Mackenzie Basin floor

25. Nationally distinctive physical characteristics 1) Naturally high-stress environments (temperature, drought & nutrients) Extremes of cold and drought, and shallow, porous, nutrient-poor soils 2) (Almost) wholly glacially derived landforms

26. Moraine The Mackenzie Basin Physical characteristics Naturally stressful environments Extremes of cold, drought, shallow nutrient-poor soils Nationally distinctive

27. Tarns and ephemeral wetlands (kettleholes)

28. Braided riverbeds & floodplains

29. Inland outwash surfaces and sand dunes

30. Distinctive evolutionary drivers 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)

31. Beak and claw - browsers, grazers, seed dispersers, understorey scratchers, pollinators….

32. Distinctive evolutionary drivers 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)

33. Conservative animals • Slow growth rates • Long time to maturity • Low fecundity • Long-lived

34. Conservative plants Tough, cryptic and slow adapted to low resource availability, infrequent defoliation, and bird herbivory

35. Bird legacies in the flora? Armoured Inpenetrable Inaccessible Unappetising (dead)

36. Big suite of small, endemic, cryptic, non grass herbs (many now threatened) No N-fixing herbs!

37. Adaptations to Low resource availability Infrequent defoliation Tough and slow woody plants Weeping matipo, Myrsine divaricata Mountain wineberry, Aristotelia fruticosa

38. No weedy northern hemisphere conifers to march across the landscape

39. Australia South Africa North America New Zealand Tough and slow grasses • Tall tussock research shows: • Unusually low root:shoot ratios • Small below-ground nutrient reserves • Slow replenishment of nutrient reserves after defoliation • (Williams 1977, Meurk 1978, Payton et al. 1986, Mark 1994) • NZ grasses in general • Slow nutrient acquisition • Slow nutrientuse • Slow growth • Tough (high tissue density) leaves and roots • Low in nitrogen • (Craine & Lee 2004, Oecologia) The ecological opposites of fast-growing, sward-forming pasture grasses

40. Podocarps (bird dispersed) Creation of the grasslands Beech Time, warming >> Shrubs and small trees (wind, then bird dispersed) Grasses Clarks Junction fossil pollen trends through the Holocene (from McGlone 2001, NZ Jecol)

41. Creation of the grasslands consolidation with Polynesian fire frequencies (> decades?)

42. Transformation of the grasslands Began with European settlement Late 19th century over-enthusiasm • “exploitative pastoralism” • More frequent burning • High stocking rates • New plants O’Connor (1986) TGML Journal

43. Transformation of the grasslands • Ongoing under pastoral grazing (Treskonova (1991) NZ Journal of Ecology) • Tall tussock grasslands to short tussock grasslands • then • Short tussock grasslands to degraded herbfields with much bare ground • Stature and density of the tussocks reduced • Decreased diversity and abundance of native species • Increase in dominance of non-native plants, especially • Exotic sward-forming grasses, • N-fixing herbs, • Grazing-resistant flatweeds (esp. mouse-ear hawkweed) • .

44. Major ecological shifts (post-settlement and pastoral periods) Slow bird herbivore fauna, to boom-bust mammal fauna Slow, stress-tolerant, fire-free, woody/shrubby vegetation with numerous cryptic non-grass herbs, to grasslands, depleted by grazing and invaded by ‘fast’ light-demanding exotic plants adapted to mammalian grazing and for rapid growth and spread • sward-forming grasses, N-fixing and resistant herbs • northern hemisphere postglacial tree “superweeds”

45. Recent trend:Intensification New open semi-natural grasslands invaded by ‘fast’ light-demanding exotic plants to wholly exotic pastures through • Oversowing and topdressing • Irrigation • Soil cultivation & cropping

46. 1990 2009 Converted by 1990 Converted by 1990 Converted between 1990 and 2009 Extent of complete conversion

47. Conversion 1990-2009 Forestry Urban/ Infrastructure 2009 Converted by 1990 Oversowing & topdressing (41%) Soil cultivation and/or irrigation (50%) Converted between 1990 and 2009

48. Remaining biodiversity of the Basin floor Flora includes: 23% of Canterbury’s ‘Threatened’ and ‘At Risk’ plants, and 11% of Canterbury’s ‘Data Deficient’ plants

49. Threatened and At Risk flora 31 species Wetlands and their margins and turfs 33 species Grassland and shrublands

50. Invertebrates Diverse, endemic, threatened Moth, grasshopper and beetle faunas especially rich & distinctive