Assessing and reporting resilience of native vegetation using VAST

Richard Thackway

Lecture presented as part of the Managing Forested Landscapes an undergraduate course , ENVS3041 Class number 4029.

Fenner School of Environment and Society, ANU

26 February 2014

Outline

• Concepts and definitions• Background to VAST framework• Why VAST-2 was developed• VAST-2 methodology • Case studies - Cumberland State Forest, Sydney• Interpreting change and trend • Lessons & conclusions

Goals of land managers

Changes in ecological function

Values and decisions matrix:• Social• Economic• Environmental

Intensification

Degradation?

Goals of land managers

Changes in ecological function

Values and decisions matrix:• Social• Economic• Environmental

Extensification

Restoration

Regulation of hydrological regime Generation of food and fibre Regulation of climate / microclimate Generation of raw materials Recycling of organic matter Creating and regulating habitats Controlling reproduction and dispersal

Changing ecological function to derive multiple benefits (ecosystem services)

VAST-2 a national standardised system for assessing vegetation resilience

Definitions - Condition and transformation

• Change in a plant community (type) due to effects of land management practices:

– Structure

– Composition

– Regenerative capacity

• Resilience = the capacity of an plant community to recover to a reference state following a change/s in land management

• Transformation = changes to vegetation condition over time• Condition, resilience and transformation are assessed relative

to fully natural a reference state

Vegetation condition

Land managers affect native veg condition in space and over time

Process: Land managers use land management practices (LMP) to influence ecological function at sites and the landscape by:• Modifying • Removing and replacing• Enhancing• Restoring• Maintaining• Improving

Purpose/s:To achieve the desired mix of ecosystem services (space & time)

1925

Occupation

Relaxation

Anthropogenic change

Net benefit

time

1900 2025 1950

Reference

chan

ge in

veg

etati

on in

dica

tor o

r ind

ex

1850 1875 1975 2000

VAST classes

VAST-2 model of ecosystem change (causes & effects)

VAST-2 focuses on tracking effects of land management on key ecological criteria

Soil

Vegetation

Regenerative capacity/ function

Vegetation structure & Species composition

1. Soil hydrological status2. Soil physical status3. Soil chemical status4. Soil biological status5. Fire regime6. Reproductive potential7. Overstorey structure8. Understorey structure9. Overstorey composition10. Understorey composition

VAST = Vegetation Assets States and Transitions NVIS = National Vegetation Information System

VIVIVIIIIII0

Native vegetationcover

Non-native vegetationcover

Increasing modification caused by use and management

Transitions = trend

Vegetation thresholds

Reference for each veg type (NVIS)

VAST - A framework for assessing & reporting vegetation condition

Condition states

Residual or unmodified

Naturally bare

Modified Transformed Replaced -Adventive

Replaced - managed

Replaced - removed

Thackway & Lesslie (2008) Environmental Management, 42, 572-90

Diagnostic attributes of VAST states:• Vegetation structure• Species composition• Regenerative capacity

NVIS

Current datasets are snapshots but not time series

Thackway & Lesslie (2008) Environmental Management, 42,

572-90

NB: Input dataset biophysical naturalness reclassified using VAST framework

/ replaced

/ unmodified

VAST 2009

Veg condition derived by classifying &

mapping effects of land management practices

Native

Aim of VAST-2

Indigenous land management

First explorers

Grazing

Deg

ree

of

mod

ifica

tion

Logging

Cropping

Site 1

Site 2

Site 3

Time

Reference state

Long term rainfall

Long term disturbance e.g. wildfire, cyclones

Revegetation

VAST classes

Generate total indices for ‘transformation site’ for each year of the historical record. Validate using Expert Knowledge

• Compile and collate effects of land management on criteria (10) and

indicators (22) over time. • Evaluate impacts on the plant

community over time

Transformation site• Compile and collate effects of

land management on criteria (10) and indicators (22)

Reference state/sites

Score all 22 indicators for ‘transformation site’ relative to the ‘reference site’. 0 = major change; 1 = no change

Derive weighted indices for the ‘transformation site’ i.e. regenerative capacity (58%), vegetation structure (27%) and species composition (18%)

by adding predefined indicators

General process for tracking change over time using the VAST-2 system

Case studies VAST-2Cumberland State Forest, Sydney

Cumberland State Forest, Sydney

Cumberland State Forest, Sydney

Cumberland State Forest 1941-2012

Red boundary shows main compartments that were cleared as per the 1943 aerial photograph. This area was fully planted out around 1944 as part of the arboretum. Except for regrowth forests: i.e. compartments 8a, 9a, 9b and 10b

1941

1943

1951

1978

1982

1984

1999

2011

2012

Field transects to survey of the overstorey and understorey

T1

T2

On-ground field survey 2012

Transect 1Cumberland SF, ex-comp 8b, 9a, 9b.Regrowth forest

Transect 2Cumberland SF, ex-comp 3a, 7a, 7b, 7c.Repurposed arboretum

On-ground field survey 2012

Key Result Areas – Regenerative capacity

Key Result Areas – Regenerative capacity

Key Result Areas – Vegetation structure

Key Result Areas – Species composition

VAST Unmodified

NSW, SB Bioregion, Cumberland SF, ex-comp 3a, 7a, 7b, 7cReference pre-European: Sydney Blue Gum High Forest

Commenced managing area for recreation. Weed control. Arboretum abandoned

Cleared & sown to improved pasture for grazing & orchard

Commenced grazing native pastures

Indigenous people manage the area

Area gazetted as State Forest, commenced planting arboretum

Area logged for building houses and fences

Commenced managing area as a future production forest. Weed control

Explorers traverse the area and site selected

Ceased grazing. Area purchased as a future working forest

VAST Unmodified

Commenced managing area primarily for recreation

Ceased grazing. Purchased & declared as a State forest

Site fenced. Commenced continuous stocking with cattle

Commenced grazing cattle

Indigenous people manage the area

Cleared and commenced regrowing forest as a future forest production

Tree cover thinned for cattle grazing

Initiated 1st hazard reduction burn

Trees logged for housing, fences & fire wood

NSW, SB Bioregion, Cumberland SF, ex-comp 8b, 9a, 9b Reference pre-European: Sydney Blue Gum High Forest

Importance of dynamics

Rainfall is assumed to be main driver of system dynamics• Period 1900 - 2013• Average seasonal rainfall (summer, autumn, …)• Rainfall anomaly is calculated above and below the mean• Two year running trend line fitted

NB: Must calibrate remote sensing to account for dynamics • e.g. ground cover, greenness and foliage projective cover

Seasonal rainfall anomaly (Lat -32.404, Long 152.496)

1901

1904

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2012

-2-1.5

-1-0.5

00.5

11.5

22.5

Spring

1901

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-3-2-1012345

Winter

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-3-2-10123456

Autumn

1901

1904

1907

1910

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2012

-2-1.5

-1-0.5

00.5

11.5

22.5

3

Summer

Source: BOM

• Network of collaborators• Ecologists, land managers, academics, research scientists,

environmental historians

• Inputs• Reference state • Historical record of land use & Land management practices• Historical record of major natural events e.g. droughts, fires, floods,

cyclones, average rainfall 1900-2012• Observed interactions e.g. rabbits, sheep and drought• Observations and quantitative measures of effects

• Include written, oral, artistic, photographic and remote sensing

Resources needed for each site

Conclusions

• VAST is a useful accounting tool for tracking change and trend in the condition of vegetated landscapes

• VAST also has value for:– Synthesizing information (quantitative and qualitative)– ‘Telling the story’ of landscape transformation– Engaging land managers and ecologists as equal players

• The VAST-2 report card helps tell the story of change and trend in vegetation condition

VAST helps in ‘telling the story’

Residual/ unmodified

Modified

Transformed

Adventive

Replaced and managed

Organ Pipes National Park – ex cropping paddock

Trajectories of vegetation status and VAST classes

reflect choices and drivers

VAST

cl

asse

s

http://portal.tern.org.au/transformation-of-australias-vegetated-landscapes-cumberland-state-forest-recommissioned-regrowth-forest-nsw

http://aceas-data.science.uq.edu.au/portal/

More info & Acknowledgements

More informationhttp://www.vasttransformations.com/http://portal.tern.org.au/searchhttp://aceas-data.science.uq.edu.au/portal/

Acknowledgements• University of Queensland, Department of Geography Planning and

Environmental Management for ongoing research support• Many public and private land managers, land management agencies, consultants

and researchers have assisted in the development of VAST & VAST-2