New Zealand’s New Zealand’s dryland biodiversity dryland biodiversity

situation: situation: How we got there and How we got there and

how we might go how we might go forwardforward Presentation to the Canterbury

Biodiversity Steering Group, Ashburton 31 July 2009.

Grant NorburySusan WalkerLandcare Research

Figure 1. The New Zealand dryland zone (after Rogers et al. 2005).

New Zealand

Dryland

What are drylands?

19% New Zealand’s land area53,000 km2

Outline

1. Current state of biodiversity

2. Pressures

3. Science-driven restoration

4. Community-driven protection and restoration

Figure 1. The New Zealand dryland zone (after Rogers et al. 2005).

New Zealand

Dryland

83% cleared (cf. 44% nationally)

3% protected (cf. 38% nationally)

~50% NZ’s threatenedflora

Drylands:• Contain some of the most transformed, least protected and most threatened native ecosystems and species in NZ

• Unstable, seral, rapidly changing, invaded

Protection and restoration are limited by:• Poor knowledge, experience and science to support biodiversity managers

• Poor agency and community awareness of dryland biodiversity and its protection needs

Land Environments of NZ

• Waitaki, Hurunui, Selwyn, Mackenzie and Ashburton districts in top 11 of all territorial authorities for environmental and ecological diversity

• Canterbury therefore contributes disproportionately and significantly to the full range of habitats and ecosystems present in NZ

% Indigenouscover left

+

LENZ

% Protected

+=

Threatened Environment Classification

Canterbury

1.00.4 0.6 0.80 0.2

The slippery slopeP

rop

ort

ion

of

spec

ies

rem

ain

ing

Proportion habitat area remaining

1.00.4 0.6 0.80 0.2

800-1200 m

< 400 m(8% remaining)

400-800 m (37% remaining)

>1200 mCanterbury habitats - habitat loss to 2001/02

Pro

po

rtio

n o

f sp

ecie

s re

mai

nin

g

Proportion habitat area remaining

Canterbury

Proportion of NZ land area Proportion of NZ

Threatened plants (2005)(Acutely and Chronically

Threatened)

Canterbury

(47%)

103 species

Nationally threatened plants in Canterbury

Ecological pressures

• Kiore (1150 yr bp)• Burning (800 yr bp)• Burning and livestock grazing (150 yr bp)• Rabbits (150 yr bp)• Ferrets, stoats, weasels, (cats) (130 yr bp)• Exotic pastures and fertiliser (130 yr bp)• Hares, hedgehogs, mice, rats, possums, goats,

magpies• Broom, briar, gorse• Cropping, viticulture, horticulture, dairying, forestry• Housing subdivisions

Pastoral farming changes

•Smaller upland blocks

•Intensive developments

Rapid, ongoing habitat loss

Mackenzie Basin

Use of spray (and fire) to clear ‘scrub’

42

35

17

0

20

40

60

May2002-Mar2003

Apr2003-Mar2004

Apr2004-Mar2005

May2002-Mar2003

Apr2003-Mar2004

Apr2004-Mar2005

Number of properties seeking Code 1 consents

Percentage of Pastoral Leases seeking Code 1 consents that

are in Tenure Review

On pastoral leases: increasing number of discretionary consents granted to clear, spray, increase stock numbers etc

Discretionary consents

Invading weeds

Pests : Feral grazers and predators

Palatable & fire sensitive species (and their fauna) long gone

Muehlenbeckia astonii on Kaitorete Spit

Cabbage tree, Canterbury Plains

Olearia hectoriiMatukituki

KowhaiLittle Valley, near

Alexandra

Hebe cupressoidesTekapo military camp

Now relicts

Seral or secondary woody communities that are expanding

Remaining natives are a spiny or toxic subset of formerly rich woody flora

Esk terraces (Canterbury)

Cloudy Range (Central Otago)

Upper Clutha (Central Otago)

Molesworth (Marlborough)

Dryands also contain a big suite of endemic herbs (many are threatened)

...and a unique, highly endangered fauna

What factors are driving species to extinction?

• Large variation from upland to lowland

• Those indigenous habitats that are retained and protected are “non representative”

• Remaining lowlands are much reduced, highly modified and poorly protected

• High numbers of threatened plants, particularly in lowland and montane zones

• Woody vegetation in flux: some winners, some losers

Current state of dryland biodiversity

Overview of research into sustaining and restoring

dryland biodiversity

Research aims

• Build expertise to enhance natural woody successions

• Build knowledge of dryland ecological patterns and processes

• Work with agencies, communities and private landowners to improve understanding and protection

Total of 8 years’ funding, 4 to go...

Biodiversity of dryland woody communities

Community and agency

awareness

Succession to native woody communities

Community mandate

Technical know-how to

achieve it

Strand 2 Strand 3Strand 1

Program strategy

Scientific mandate and

vision

Impacts on some dryland fauna

Pest–Pest

interactions

Aligned work on pests

Succession to native woody communities

1. What limits native woody succession?

2. What practical, broad scale solutions can be developed to overcome these?

Strand 1

PLOT & POINT

locations in drylands

(n = 9935)

POLYGONS in drylands(n = 1148)(some not digitised)

Distributions Database

1. Gather known data on woody species distributions

2. Model distributions with respect to environment

3. Identify potential succession pathways

4. Identify best native woody species for trials at different sites

Marlborough/North Canterbury

Stage I Stage II Stage III Stage IV

Rosa rubiginosa* Rosa rubiginosa* Coprosma propinqua Coprosma rotundifolia

Melicytus alpinus Melicytus alpinus Kunzea ericoides Clematis forsteri

Discaria toumatou Discaria toumatou Coprosma rhamnoides Ripogonum scandens

Kunzea ericoides Discaria toumatou Coprosma propinqua

Coprosma propinqua

Ozothamnus leptophyllus

Alectryon excelsus

Olearia odorata Melicytus ramiflorus Carpodetus serratus

Rubus schmidelioides Coprosma rhamnoides

Muehlenbeckia complexa

Kunzea ericoides

Rosa rubiginosa* Melicytus ramiflorus

Carpodetus serratus Pseudopanax crassifolius

Myrsine australis

Rosa rubiginosa*

Ranked probability of occurrence of woody species

Species-poor to species-rich communities

Traits Database

Height Seed size

Width Seed bank type

Leaf longevity Spinosity

Sexual reproduction system

Toxicity

Age till flowering Palatability to animals

Pollination agent Resprout after grazing/cutting

Dispersal agent N-fixation

Number of seeds/plant/crop

Shade tolerance

Years between crops Fire tolerance

Seed mass Frost tolerance

300 species (200 native, 100 exotic)

20 traits

1. Gather existing trait data for dryland woody species

2. Combine with Distribution Database to – Identify spatial pattern of traits syndromes – Identify whether (and if so what) traits predict

successful secondary succession and where

Limitations to establishment

• Understand limitations to woody establishment • Test low intensity management tools• Work towards general model

Dispersal

Germination

Growth

Mortality

Climate

Soils

Shrub cover

Herbivore pressure

Soil water

Decomposition

Sward density

Navail

BNPP, ANPP, Litter

Wavail, BNPP,ANPP, Litter

Light

In progress…..modified from Peters 2002 Ecol. Model. 152:5-32

How do soil characteristics interact with moisture to affect growth in woody

seedlings?

7 soils

semi-aridschist

lime

brown / loess

volcanic

pallic

Role of competition and herbivory in woody seedling

establishment

Bendigo, Central Otago

• +/- water

• +/- herbivory

• +/- competition (herbicide + hand weeding)

• 4 species

Conclusions so far…

Herbivory always bad, but competition has net benefit in some places

Water (at least last year) made little difference

How does grass sward density affect establishment of woody seedlings?

A field & glasshouse experiment

Still to come…

How does shelter and coarse woody

debris affect establishment?

What are benefits and drawbacks of woody succession for native biodiversity in drylands?

Demonstration of gains and losses associated with woody dominance

Biodiversity of dryland woody communities

Strand 2

Woody Intermediate Non-woody

No. native plant species

0

20

40

60

80

100

120

Region (3sites)

Bendigo BlackstoneHill

Cambrian

Grassy Intermediate Woody

No.

nat

ive

plan

t sp

ecie

s

No. native bird species

0

1

2

3

4

5

6

7

Region (all 3sites)

Bendigo BlackstoneHill

Cambrian

Grassy Intermediate Woody

No.

nat

ive

bird

spe

cies

All lizardsLizards

Partnership with DOC Grand and Otago Skink Recovery Programme

Led by DOC (Canterbury) with range of co-funders

• Can native woody species establish in exotic woody stands in drylands?

• Do woody weeds facilitate native establishment in dryland environments?

Factors affecting native woody establishment in exotic broom

Ealing Springs

Treatments

Solid broom (control)

Roller crushed

SprayedMulched

Root raked

We want to be able to provide advice about a biodiverse future:

What could develop through succession?

What is a priority to protect and/or restore?

What can we just leave to its own devices?

Pest interactions

Grazing & Burning

Vegetation

Native lizard

Native invert

Ferret Cat Stoat

Superpredators

Possum

Rabbit

Hare

Herbivores

Rat

Mouse

Mesopredators

Hedgehog

Insectivore

Climate

Ferret Cat

Grazing & Burning

Shrubland

Possum

Native lizard

Native invert

Rabbit

Hare

Rat

Mouse

Hedgehog

Superpredators

Herbivores Mesopredators Insectivore

Stoat

Habitat and pests interact

1990 2003

5 km

Community-driven protection and restoration

Distribution of community restoration projects

Land areas (ha) covered by BCF projects

0 1000 2000 3000 4000 5000 6000

Northland

Auckland

Waikato

E. Coast

Tong/Tau

BoPlenty

Wanganui

Wellington

Nel/Marl

Canter

Otago

Southland

Sociala. Historical inertia

b. Poor understanding

Biologicala. Habitat loss and modification

b. Invasive species

Drivers of biodiversity decline

Problems SolutionsSocial

Poor understanding Educate people

Involve the community

Help management agencies

BiologicalHabitat loss and modification Purchase land for the public

Protection on private land

Tenure review (?)

Invasive species DoC

Private ‘sanctuaries’/covenants

Community groups

Life-stylers

Councils have big challenges

• Dual development and conservation roles

• Optimum mix of regulation and voluntary approaches

• Socio-political context

A bottom line

Need to cap indigenous vegetation loss

Indigenous vegetation needs to be defined broadly

Invest in an aware constituency Work with willing landowners

Inform, advise, educate, incentivise, participate in activities

Monitor and report losses as well as gains

Build in-house biodiversity capability

Needs (to sustain biodiversity)

We celebrate weeds!!

These are Central Otago’s kiwi !

Public education tours

Aldinga Conservation

Area

Central Stories

Thankyou