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