Post on 05-Aug-2020
The Mackenzie Basin – ecology and protection
Nicholas Head
Plant Ecologist
Photo Chris Woolmore
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)
Ceratocephala pungens
Leptinella conjuncta
Myosurus minimus
...inland alluvial surfaces and
associated nationally threatened plants…
...inland dunes and threatened plants…
Pimelea pulvinaris
Lepidium solandri
Carmichaelia vexillata
...moraines, kettleholes and threatened plants …
Cardamine ‘Tarn’ Iphigenia novae-zelandiae
Isolepis basilaris
Braided rivers and threatened rare birds
black-fronted tern
black-billed gull
banded dotterel
black stilt
wrybill
oystercatcher
Wetlands and threatened rare freshwater fish
Upland alpine galaxias
koaro Lowland longjaw 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
Hexathele aff. petriei
Sigaus minutus Brachaspis robustus
Hemiandrus sp
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
... also protecting ‘iconic’ landscapes and scenic corridors adjoining a major
highway and tourist route
- vistas long appreciated by generations of NZers
Photo: Chris Woolmore
...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?)
• 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!
…but…Increasing Threats and Diminishing
Opportunities
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!
Monitoring Plots Tekapo Scientific Reserve 1992 - 20011
1992 2011
Photo Chris Woolmore
• 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.
Summary