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