Transcript Slide 1

Grant Norbury
Susan Walker
Landcare Research
New Zealand’s
dryland biodiversity
situation:
How we got there and
how we might go
Presentation to the Canterbury
forward
Biodiversity Steering Group,
Ashburton 31 July 2009.
What are drylands?
19% New Zealand’s
land area
53,000 km2
New Zealand
Dryland
Outline
1. Current state of biodiversity
2. Pressures
3. Science-driven restoration
4. Community-driven protection and
restoration
83% cleared (cf. 44% nationally)
3% protected (cf. 38% nationally)
~50% NZ’s
threatened
flora
New Zealand
Dryland
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
LENZ
Canterbury
% Indigenous
cover left
% Protected
+
Threatened Environment Classification
+
=
Proportion of species remaining
The slippery slope
0
0.2
0.4
0.6
0.8
Proportion habitat area remaining
1.0
Canterbury habitats - habitat loss to 2001/02
>1200 m
Proportion of species remaining
800-1200 m
400-800 m
(37% remaining)
< 400 m
(8% remaining)
0
0.2
0.4
0.6
0.8
Proportion habitat area remaining
1.0
Nationally threatened plants in
Canterbury
Proportion of NZ land area
Proportion of NZ
Threatened plants (2005)
(Acutely and Chronically
Threatened)
Canterbury
Canterbury
(47%)
103 species
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
Rapid, ongoing habitat loss
Pastoral farming
changes
•Smaller upland blocks
•Intensive developments
Mackenzie Basin
Use of spray (and fire) to clear ‘scrub’
Discretionary consents
On pastoral leases: increasing number of discretionary consents
granted to clear, spray, increase stock numbers etc
Number of properties seeking
Code 1 consents
Percentage
seeking Co
are in
60
42
40
20
35
17
0
May2002Mar2003
Apr2003Mar2004
Apr2004Mar2005
May2002Mar2003
A
M
Invading weeds
Pests : Feral grazers and predators
Palatable & fire sensitive species (and their fauna) long gone
Now relicts
Olearia hectorii
Matukituki
Kowhai
Little Valley, near
Alexandra
Hebe cupressoides
Tekapo military camp
Muehlenbeckia astonii on Kaitorete
Spit
Cabbage tree,
Canterbury Plains
Seral or secondary woody communities that are expanding
Upper Clutha (Central Otago)
Molesworth (Marlborough)
Cloudy Range
(Central Otago)
Esk terraces (Canterbury)
Remaining natives are a spiny or toxic subset
of formerly rich woody flora
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?
Current state of dryland biodiversity
•
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
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...
Program strategy
Strand 1
Strand 2
Strand 3
Succession to
native woody
communities
Biodiversity of
dryland woody
communities
Community and
agency
awareness
Technical
know-how to
achieve it
Scientific
mandate and
vision
Community
mandate
Aligned work on pests
Pest–Pest
interactions
Impacts on some
dryland fauna
Strand 1
Succession to
native woody
communities
1.
What limits native woody
succession?
2.
What practical, broad scale
solutions can be developed
to overcome these?
1.
Distributions
Database
2.
3.
4.
PLOT &
POINT
locations in
Gather known data on woody species
distributions
Model distributions with respect to
environment
Identify potential succession pathways
Identify best native woody species for
trials at different sites
POLYGONS
in drylands
Marlborough/North Canterbury
Ranked probability of occurrence of woody species
Species-poor to species-rich communities
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*
Traits
Database
1.
Gather existing trait data for dryland
woody species
Combine with Distribution Database to
2.
–
–
300 species
Identify spatial pattern of traits syndromes
Identify whether (and if so what) traits predict
successful secondary succession and where
(200 native, 100 exotic)
20 traits
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
Limitations to establishment
• Understand limitations to woody establishment
• Test low intensity management tools
• Work towards general model
Dispersal
Sward density
Climate
Light
Germination
Soil water
Wavail,
BNPP,
ANPP, Litter
Growth
Navail
Soils
Decomposition
BNPP,
ANPP, Litter
Mortality
In progress…..modified from Peters 2002 Ecol. Model. 152:5-32
Shrub
cover
Herbivore
pressure
7 soils
pallic
volcanic
lime
brown /
loess
semi-arid
schist
How do soil characteristics interact with
moisture to affect growth in woody
seedlings?
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?
Strand 2
Biodiversity of
dryland woody
communities
What are benefits and
drawbacks of woody
succession for native
biodiversity in drylands?
Demonstration of gains and
losses associated with woody
dominance
Woody
Intermediate
Non-woody
No. native plant species
No. native plant species
120
Grassy
Intermediate
Woody
100
80
60
40
20
0
Region (3
sites)
Bendigo
Blackstone
Hill
Cambrian
No. native bird species
No. native bird species
7
Grassy
Intermediate
Woody
6
5
4
3
2
1
0
Region (all 3
sites)
Bendigo
Blackstone
Hill
Cambrian
Lizards
All lizards
Partnership with DOC Grand and Otago
Skink Recovery Programme
Factors affecting native woody
establishment in exotic broom
Ealing Springs
Led by DOC (Canterbury) with range of cofunders
• Can native woody species establish in exotic woody
stands in drylands?
• Do woody weeds facilitate native establishment in
dryland environments?
Treatments
Roller crushed
Solid broom (control)
Root raked
Mulched
Sprayed
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
Superpredators
Ferret
Herbivores
Stoat
Mesopredators
Rabbit
Possum
Cat
Rat
Hare
Insectivore
Hedgehog
Mouse
Native lizard
Native invert
Vegetation
Grazing & Burning
Climate
Superpredators
Ferret
Herbivores
Mesopredators
Rabbit
Possum
Cat
Rat
Hare
Stoat
Insectivore
Hedgehog
Mouse
Native lizard
Shrubland
Grazing & Burning
Native invert
Habitat and pests interact
1990
5 km
2003
Community-driven protection and
restoration
Distribution of
community
restoration
projects
Land areas (ha) covered by BCF projects
Southland
Otago
Canter
Nel/Marl
Wellington
Wanganui
BoPlenty
Tong/Tau
E. Coast
Waikato
Auckland
Northland
0
1000
2000
3000
4000
5000
6000
Drivers of biodiversity decline
Social
a. Historical inertia
b. Poor understanding
Biological
a. Habitat loss and modification
b. Invasive species
Problems
Solutions
Social
Poor understanding
Educate people
Involve the community
Help management agencies
Biological
Habitat 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
Needs (to sustain biodiversity)
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
We celebrate weeds!!
These are Central Otago’s
kiwi !
Public education tours
Aldinga
Conservation
Area
Central
Stories
Thankyou