The Mackenzie Basin – ecology and protection
Photo Chris Woolmore
Nicholas Head Plant Ecologist
Acknowledgements
Warren Chinn, Joy Comrie, Iain Gover, Di Lucas, Brian Patrick, Geoff Rogers, Susan Walker, Chris Woolmore Background
Largest inter-montane basin in NZ
Characterised by: • climatic extremes = ecologically distinctive ‘desert character’ (semi- arid; drought and frost, hot and cold)
• comprises extensive sequences of nationally rare glacial derived ecosystems
• rich biodiversity and strongholds for many threatened species ~ 24% Canty’s threatened and uncommon plants (>60 spp)
• wide open landscapes of distinctive ‘undeveloped’ glacial landforms
Photo G. Denton
Sequences of glacial landforms. High geographical and environmental variation at macro and micro scale. Ref: Cooksley 2008 Pre–human Vegetation
12,000 ybp – rock, gravel, bare ground, colonising herbaceous vegetation
5,000 ybp complex woody mosaic: • open conifer forest and scrub on humid hill slopes and moraines
• scrub, red and fescue tussock on driest and youngest surfaces
• rich biodiversity adapted to open naturally disturbed habitats (climate and fauna)
• natural fire rare
Arrival of Maori ~900 ybp
• extensive fire
• loss of hill slope forest and basin floor conifer forest/scrub
• down slope migration of snow tussock
• expansion of fescue tussock, red tussock and scrub across basin floor
• extinction of large birds Arrival of Europeans ~ 1840
European arrival • extensive fescue tussock, red tussock and scrub
• dune lands
“rivers of sand” (surveyor general 1850s)
“great tawny expanse of low tussock grassland” (von Haast 1862)
• Continued depletion – weeds, pests overgrazing
(refs: von Haast. 1870; Cockayne, L. 1919; Zotov, V.1938; Molloy et al 1963; Connor, H. 1964; O’Connor, K. 1982; Burrows, C. 1996; McGlone et al. 1998; 2001; Walker et al. 2003)
Water colour by surveyor Thompson (1857) Despite long history of disturbance and ecosystem depletion by humans, much of the Mackenzie retains its natural character and biological values. Mackenzie Basin: - National Stronghold for Naturally Rare Ecosystems
• Especially: - inland alluvial surfaces, inland dunes, moraines, kettleholes, braided rivers, wetlands
• Unparalleled for their extent and diversity
• Occur in contiguous sequences
• Provide habitats for numerous rare and threatened species
• The protection of naturally rare ecosystems and habitats for threatened species are national priorities (Mf E 2007)
...inland alluvial surfaces and associated nationally threatened plants…
Leptinella conjuncta
Myosurus minimus Ceratocephala pungens
...inland dunes and threatened plants…
Lepidium solandri
Pimelea pulvinaris
Carmichaelia vexillata ...moraines, kettleholes and threatened plants …
Isolepis basilaris
Iphigenia novae-zelandiae Cardamine ‘Tarn’ Braided rivers and threatened rare birds
black-fronted tern
banded dotterel
wrybill
black-billed gull
oystercatcher Wetlands and threatened rare freshwater fish
Lowland longjaw galaxias koaro
Upland alpine galaxias ‘Bignose’ galaxias Important Invertebrate Values
Extremely high numbers of species, esp. moths, beetles and grasshoppers (31 native moths)
Many endemic and highly threatened species (4 nationally critical moths, 1 nationally endangered)
Critical importance of ‘depleted habitats’: - “dunes”, rocky, bare ground, depressions of low-growing plants, cushion vegetation, scarps, terraces, riverbed, seasonal wetlands and fescue tussock
Brachaspis robustus Sigaus minutus
Hemiandrus sp Hexathele aff. petriei Mackenzie Basin: - also a Stronghold for Nationally Threatened and At Risk Ecosystems
• New Zealand’s low-lying ecosystems have undergone a very high degree of development
• Few natural areas remain and those that do are poorly protected
• As a result the protection of indigenous biodiversity on threatened land environments is a national priority (MfE 2007)
• The Mackenzie retains some of the largest areas of undeveloped threatened and at risk ecosystems remaining in New Zealand Tenure Review’s Dryland Park Concept
• In recognition of the Mackenzie’s distinctiveness and its importance for NZ’s rare and threatened dryland biodiversity
• And that few other (if any) opportunities remain in NZ to protect similar values at ‘large’ scales and along contiguous ecological sequences
• Drylands Park acknowledged by Parliamentary Commissioner for the Environment as a highly desirable conservation objective
Photo: Chris Woolmore
... also protecting ‘iconic’ landscapes and scenic corridors adjoining a major highway and tourist route - vistas long appreciated by generations of NZers ...promoting opportunities for ‘Tourism and the Conservation Economy’
• Outstanding recreation opportunities: mountain biking, tramping, cycling, hunting, fishing etc
• Much greater potential for increased use: Corridor from to the Basin floor to Aoraki National Park. Rational for Protection - Relevant Legislative and Policy Framework
• CPLA = ‘protect inherent natural values’ • PNAP and numerous RAPS in Mackenzie (1980’s ) • RMA (1991) = requires protection of significant ecological values • Tenure Review = ‘protection’ of significant inherent values (biodiversity and landscape) • New Zealand Biodiversity Strategy (MfE 2000) • National Priorities for protection (MfE 2007) • NRRP (2011?)
…but…Increasing Threats and Diminishing Opportunities • Extensive loss and fragmentation occurring in the Mackenzie
- biologically rich dryland ecosystems being lost
- significant natural landscapes lost
• e.g. Twizel to Omarama road corridor was until recently an ecosystem of national significance for invertebrates!
• Much more planned! Canterbury Plains The upper Waitaki Basin! Other threats = Weeds and pests Management and Sustainability of Dryland Ecosystems
The Tekapo Scientific Reserve
• Dryland ecosystems typically depleted through a long history of burning, sheep, rabbits, weeds, but most retain ecological values.
• Even the most depleted ecosystems can recover with appropriate management and patience!
1992 2011
Monitoring Plots Tekapo Scientific Reserve 1992 - 20011 Summary
• The Mackenzie Basin is one the most ecologically distinctive areas in New Zealand • a stronghold for many rare ecosystems and threatened species of national priority to protect • presents a ‘unique’ challenge as one of last opportunities to protect dryland ecosystems in New Zealand at a sustainable scale • Although depleted and facing numerous threats, dryland ecosystems are resilient with appropriate management.
Photo Chris Woolmore