Tracking the Transformation of VegetatedLandscapes (VAST)

Richard Thackway

NSW ECA Conference Fairmont Resort at Leura in the Blue Mountains : 2nd August 2013

Offsets: determination, assessment and management

Outline

• Concepts and definitions• Overview of VAST framework• Conceptual model for tracking change and trend• VAST-2 system• Case studies• More information

1. Remaining extent of

native vegetation

2. Remaining extent of native vegetation

types

3. Remaining extent of native vegetation types compared to pre-Euro

vegetation types

4. Proportion of remaining native vegetation types in specified condition

classes

Monitoring and reporting vegetation (maps)

Based on: NLWRA 2007

VASTVAST

What is condition and transformation?

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

– Structure

– Composition

– Regenerative capacity

• Transformation = changes to vegetation condition over time• Condition and transformation can be assessed relative to fully

natural a reference state

Vegetation condition

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

VIVIVIIIIII0

Native vegetationcover

Non-native vegetationcover

Increasing vegetation modification

Transitions = trend

Vegetation thresholds

Reference for each veg type (NVIS)

VAST - A framework for reporting vegetation condition

Condition states

Unmodified/ Residual

Naturally bare

Modified Transformed Replaced -Adventive

Replaced - managed

Replaced - removed

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

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

NVIS

Native vegetation extentDominant structuring plant species indigenous to the locality and spontaneous in

occurrence – i.e. a vegetation community described using definitive vegetation types relative to estimated pre1750 states

Non-native vegetation extentDominant structuring plant species indigenous to the locality but

cultivated; alien to the locality and cultivated; or alien to the locality and spontaneous

Vegetation condition Class (mapping criteria)

UNMODIFIEDnative vegetation

community structure, composition, and

regenerative capacity intact – no significant

perturbation from land use/land management

practice

MODIFIEDnative vegetation

community structure, composition and

regenerative capacity intact - perturbed by

land use/land management practice

TRANSFORMEDnative vegetation

community structure, composition and

regenerative capacity significantly altered by

land use/land management practice

REPLACED - ADVENTIVE

native vegetation replacement – species

alien to the locality and spontaneous in

occurrence

REPLACED - MANAGED

native vegetation replacement with

cultivated vegetation

REMOVEDvegetation removed -

alienation to non-vegetated land

cover

Examples

Old growth forests; Native grasslands that have not been grazed; Wildfire in

native forests and woodlands of a natural

frequency and/or intensity;

Native vegetation types managed using

sustainable grazing systems; Selective timber

harvesting practices; Severely burnt (wildfire)

native forests and woodlands not of a

natural frequency and/or intensity

Intensive native forestry practices; Heavily grazed

native grasslands and grassy woodlands;

Obvious thinning of trees for pasture production; Weedy native remnant

patches; Degraded roadside reserves;

Degraded coastal dune systems; Heavily grazed

riparian vegetation

Severe invasions of introduced weeds;

Invasive native woody species found outside

their normal range; Isolated native

trees/shrubs/grass species in the above

examples

Forest plantations; Horticulture; Tree

cropping; Orchards; Reclaimed mine sites;

Environmental and amenity plantings; Improved pastures.

(includes heavy thinning of trees for pasture);

Cropping; Isolated native trees/ shrubs/ grass species in the above

examples

Water impoundments;

Urban and industrial

landscapes; quarries and

mines; Transport infrastructure; salt

scalded areas

Active restoration e.g. Landscape reshaping and hydrological works, soil

treatment, revegetation, encouragement of regeneration capacity

Rehabilitation & passive restoratione.g. weed removal, re-seeding of understorey, controlled burning, stabilisation of dunes, re-

establishment of riparian community flooding regimes

Offsets and VAST classes in the short term

Offsets

Vegetation condition (VAST) – a snapshot

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

NB: Input dataset biophysical naturalness reclassified using VAST framework

/ replaced

/ unmodified

 

Replaced and managed

(VAST V)

Unmodified vegetation (VAST I)

Transformed vegetation (VAST III)

Adventive (VAST IV)

Map of vegetation condition – a snap shot

1. Remaining extent of

native vegetation

2. Remaining extent of native vegetation

types

3. Remaining extent of native vegetation types compared to pre-Euro

vegetation types

4. Proportion of remaining native vegetation types in specified condition

classes

Tracking change and trend in condition

Effects of management

action decisions (PAST, PRESENT

& FUTURE

Resource change and trend reporting

VAST-2

VASTVAST

Occupation

Relaxation

Anthropogenic change

Net impact

years

Based on Hamilton, Brown & Nolan 2008. FWPA PRO7.1050. pg 18Land use impacts on biodiversity and Life Cycle Analysis

Reference

Models of ecosystem change i.e. net lossch

ange

in v

eget

ation

indi

cato

r/s

1800 1825 1850 1900 1925 1950 1975 2000 2025

Occupation

Relaxation

Anthropogenic change

Net benefit

years

Reference

Models of ecosystem change i.e. net gainch

ange

in v

eget

ation

indi

cato

r/s

Baseline

Management intervention/s

1800 1825 1850 1900 1925 1950 1975 2000 2025

1800 1825 1850 1900 1925 1950 1975 2000 2025

100

80

60

40

20

0

VAST Class

Inferred impacts of land use on vegetation condition - ‘potential’ future condition

Current land use: Continuous grazing of derived grassland

Unmodified/ Residual

Replaced - removed

Replaced - managed

Replaced -Adventive

Modified

VAST

cla

sses

time

Transformed

?

Why use land management and not land use?

1850s

2000s

Increasing intensification

Stata: U = upper, M = mid, G = groundRC = Regenerative capacity, VS = Vegetation structure, SC = Species composition

% Foliage Cover

HeightU

M

G

Woodland

% Foliage Cover

HeightU

M

G

Open Woodland

% Foliage Cover

HeightU

M

G

Grassland with scattered trees

Cattle grazing native pasture

Cattle grazing native pasture

Cattle grazing native pasture

Land use VAST Class

I

II

III

Indicators of vegetation structure

VAST III: TransformedVAST I: Unmodified

How VAST assesses transitions between states?

VAST defines what indicators are effected by management practices:

Plant community

type

Regenerative capacity

Vegetation structure

Species composition

Increasing vegetation modification Reference state

TARGET of action

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

Soil

Vegetation

LUMIS

PURPOSE of activity is to :

Focus on what the land manager is doing that effect veg condition

Soil

Vegetation

Regenerative capacity/ function / processes - VAST

Vegetation structure & Species composition - VAST

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

LUMIS

PURPOSE of activity is to :

Focus on what the land manager is doing that effect veg condition

VAST-2 System

Tracking change in vegetation condition

Condition components (3)

[VAST]

Attribute groups (10)

[LUMIS]Description of loss or gain relative to pre settlement indicator reference state

(22)

Regenerative capacity

Fire regime Area /size of fire foot prints

Number of fire starts

Soil hydrology Soil surface water availability

Ground water availability

Soil physical state

Depth of the A horizon

Soil structure

Soil nutrient state

Nutrient stress – rundown (deficiency) relative to soil fertility

Nutrient stress – excess (toxicity) relative to soil fertility

Soil biological state

Recyclers responsible for maintaining soil porosity and nutrient recycling

Surface organic matter, soil crusts

Reproductive potential

Reproductive potential of overstorey structuring species

Reproductive potential of understorey structuring species

Vegetation structure

Overstorey structure

Overstorey top height (mean) of the plant community

Overstorey foliage projective cover (mean) of the plant community

Overstorey structural diversity (i.e. a diversity of age classes) of the stand

Understorey structure

Understorey top height (mean) of the plant community

Understorey ground cover (mean) of the plant community

Understorey structural diversity (i.e. a diversity of age classes) of the plant

Species Composition

Overstorey composition

Densities of overstorey species functional groups

Relative number of overstorey species (richness) of indigenous to exotic species

Understorey composition

Densities of understorey species functional groups

Relative number of understorey species (richness) of indigenous to exotic species

1

3

10

22

Dia

gnos

ticatt

ribut

es

VegetationTransformation

score

Attrib

ute

grou

ps

VegetationStructure

(27%)

Overstorey

(3)

Understorey

(3)

SpeciesComposition

(18%)

(2)

UnderstoreyOverstorey

(2)

RegenerativeCapacity

(55%)

Fire

(2)

Reprodpotent

(2)

Soil

Hydrology

(2)

Biology

(2)

Nutrients

(2)

Structure

(2) Indicators

VAST-2 hierarchy

Step 7Add the indices for the three components to generate total transformation

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

Step 1aUse a checklist of 22 indicators to compile

changes in LU & LMP* and plant community responses over time

Transformation site

Step 1cEvaluate impacts on the plant community

over time

Step 1bEvaluate the influence of climate, soil and

landform on the historical record

Step 2Document responses of 22

indicators over time

Step 4Document the reference states for 22 indicators

Step 3aLiterature review to determine the

baseline conditions for 22 indicators

Step 3cCompile indicator data for 22 indicators for reference site

Step 3bEvaluate the influence of climate, soil and landform for the reference site

Reference state/sites

Step 5Score all 22 indicators for ‘transformation site’ relative to the

‘reference site’. 0 = major change; 1 = no change

Step 6Derive weighted indices for the three components for the ‘transformation

site’ i.e. regenerative capacity (58%), vegetation structure (27%) and species composition (18%) by adding predefined indicators

General process for tracking changes VAST-2 system

* LU Land useLMP Land management practices

Importance of dynamics

Rainfall 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: Rainfall also drives signal in some remote sensing products

WA Wheatbelt BOM rainfall anomaly 1900-2010(modelled 5 km resolution)

Derived from monthly modelled rainfall data obtained from http://www.longpaddock.qld.gov.au/silo/

Rainfall anomaly relative to mean

Case studies VAST-2

V

IV

III

II

I

V

IV

III

II

I

Approaches for accounting for net gains

Quantitative accounting ‘Defaults’-based accounting• Rigorous and repeatable

measurement at sites

• High accuracy and precision

• High costs (method development, field-based measurement costs, verification)

• High skill levels too complex for citizen science

• Potential barrier in high variability / low per-area return activities (e.g. rangelands)

• Observations collected at sites over time. +ve & -ve scoring of indicators tied to changes in land management

• Relatively accurate and lower precision

• Low cost involving a partnership between land managers and ecologists

• Attractive for engaging citizen scientists

• Attractive for land manager reporting incl. site photos and record keeping

• Utilise where appropriate, rigorous and repeatable site-based measurements

VAST-2

VAST classes

Native (based on dominant structuring species = >50 %

cover)

Non-native (based on dominant structuring species = >50 %

cover)

Unmodified (100-81)

Modified(80-61)

Transformed (60-41)

Adventive (40-21)

Replaced & managed

(20-1)

Replaced & removed

(<1)

Fully natural reference e.g.

Box gum woodland

Short term(~<10 yrs)

Medium term

(~10-50 yrs)

Long term (~>50 yrs)

Tim

e re

quire

d to

reco

ver f

ully

na

tura

l ref

eren

cePredicted recovery times for plant community types

The role of remote sensing:Health or Condition?

• Some remote sensing products can be health measures and NOT condition e.g. – Normalised Difference Vegetation Index (NDVI)– Fractional cover – Leaf Area Index (LAI)

• However, some remote sensing products can be used to upscale some condition indicators in VAST-2 e.g.– Lidar to determine Top height of the overstorey– Landsat to determine Foliage projective cover of the overstorey – Radar-based satellites and Lidar to determine Structural diversity

derived from– Landsat to determine Ground cover

• .• Freehold no grazing• Multiple strata, some emergents• Biomass ~120 t/ha • FPC ~ 52%, Max height ~ 24m• Spp OverS 3-5, MidS 5+, GroundS 5-10• Regen - good

• .• Freehold - grazing • Two strata• Biomass ~68 t/ha • FPC ~ 25%, Max height ~ 17m• Spp OverS 3, MidS 1, GroundS ~1-4• Regen – Low-Moderate

• .• Freehold - heavy grazing - mechanical thinning• Single, low height strata • Biomass ~42 t/ha • FPC ~ 20%, Max height ~ 13m• Spp OverS 3, MidS 0, GroundS ~1-4• Regen – very low, > % bare ground

Site: p143

Site: p142-18

Site: p142-02

Site-based surveys LidarVAST I - Unmodified

VAST II – Modified

VAST III – Transformed

Compiled by Qld EPA based on the average ground cover disturbance index

Desert Uplands, Qld

Source: Doug Ward

Ground Cover Disturbance Index Landsat 1988-2004

Conclusions

• Vegetation condition can be changed and can be tracked using indicators of the effects of land management practices

• VAST-2 system has value for:– Engaging land managers as citizen scientists – Synthesizing information (quantitative and qualitative)– ‘Telling the story’ of vegetation condition and transformation

More info & Acknowledgements

•More information•http://www.vasttransformations.com/

•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 provided data and information