A framework for assessing and reporting resilience of native vegetation
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
2 March 2016
Outline
• Concepts and definitions• Why & how land managers change their landscapes• A standardised system for assessing and reporting resilience • The VAST methodology site and landscape • Case studies - Cumberland State Forest, Sydney• 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)
A framework for assessing and reporting vegetation resilience
Definitions
• Change in a plant community type due to effects of land management practices:
– Structure
– Composition
– Regenerative capacity• Resilience = capacity of an plant community to recover toward
a reference state following 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
A model of ecosystem change (causes & effects)
Variable date?reference state = Unmodified
Understanding states and transitions(space and time)
Indigenous land management
First explorers
Grazing
Degr
ee o
f m
odifi
catio
n
Logging
Cropping
Site 1
Site 2
Site 3
Time
Reference state
Long term rainfall
Long term disturbance e.g. wildfire, cyclones
Revegetation
VAST states The same ecosystem e.g. eucalypt open forest with different management histories
t2t1t3
Land managers change 10 key criteria affecting the resilience of a plant community
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)
A framework for assessing & reporting changes in plant communities
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
Condition of plant communities – a snap shot
Thackway & Lesslie (2008) Environmental Management, 42,
572-90
NB: Input dataset biophysical naturalness reclassified using VAST framework
/ replaced
/ unmodified
VAST 2009
Native
Aggregate reporting using a hierarchy of regions
1) Agro-climatic, 2) IBRA, 3) IBRA sub-regions
Aggregate reporting of classes of resilience using agro-climatic regions
Aggregate reporting of classes of landscape alteration levels
Synthesising information using a hierarchy
• Level 1: Scores over time• Level 2: Components• Level 3: Criteria• Level 4: Indicators• Level 5: Field measures/observations (Direct) and Expert /inference
models (Indirect)
Components (Level 2)
Criteria(Level 3)
Description of loss or gain relative to pre settlement indicator reference state (Level 4)
Regenerative
capacity
Fire regime Change in the area /size of fire foot prints Change in the number of fire starts
Soil hydrology Change in the soil surface water availabilityChange in the ground water availability
Soil physical state
Change in the depth of the A horizon Change in soil structure.
Soil nutrient state
Nutrient stress – rundown (deficiency) relative to soil fertility Nutrient stress – excess (toxicity) relative to soil fertility
Soil biological state
Change in the recyclers responsible for maintaining soil porosity and nutrient recycling Change in surface organic matter, soil crusts
Reproductive potential
Change in the reproductive potential of overstorey structuring species Change in the reproductive potential of understorey structuring species
Vegetation structure
Overstorey structure
Change in the overstorey top height (mean) of the plant community Change in the overstorey foliage projective cover (mean) of the plant community Change in the overstorey structural diversity (i.e. a diversity of age classes) of the stand
Understorey structure
Change in the understorey top height (mean) of the plant community Change in the understorey ground cover (mean) of the plant community Change in the understorey structural diversity (i.e. a diversity of age classes) of the plant
Species Compositi
on
Overstorey composition
Change in the densities of overstorey species functional groups Change in no.s of indigenous overstorey species relative to the number of exotic species
Understorey composition
Change in the densities of understorey species functional groups Change in no.s of indigenous understorey species relative to the number of exotic species
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 (55%), 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
Field transects to survey of the overstorey and understorey
T1
T2
Site level
On-ground field survey 2012
Transect 1Cumberland SF, ex-comp 8b, 9a, 9b.Regrowth forest
StructureComposition Function
Transect 2Cumberland SF, ex-comp 3a, 7a, 7b, 7c.Repurposed arboretum
On-ground field survey 2012
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
T2
Transect 2 = T2
Compartments
1941
T2
1943
T2
1951
T2
1978
T2
1982
T2
1984
T2
1999
T2
2011
T2
2012
T2
NSW, SB Bioregion, Cumberland SF, ex-comp 3a, 7a, 7b, 7c Vegetation structure
Indicators:#13: Height#14: Foliage cover#15: Age structure
Indicators:#16: Height#17: Foliage cover#18: Age structure
Criteria #7
Criteria #8
NSW, SB Bioregion, Cumberland SF, Transect 2 (ex-comp 3a, 7a, 7b, 7c)Function – Regenerative capacity
Criteria #1 Criteria #2
Criteria #3 Criteria #4
NSW, SB Bioregion, Cumberland SF, Transect 2 (ex-comp 3a, 7a, 7b, 7c)Function – Regenerative capacity
Criteria #5 Criteria #6
NSW, SB Bioregion, Cumberland SF, Transect 2 (ex-comp 3a, 7a, 7b, 7c)Species composition
Criteria #9
Criteria #10
1
3
10
22
Com
pone
nts
(3)
VegetationTransformation
Score (1)
Crite
ria(1
0)
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
(22)
Synthesisng the effects of land management on indicators over time
Level
1
2
3
4
Count
NSW, SB Bioregion, Cumberland SF, Transect 2 (ex-comp 3a, 7a, 7b, 7c)Reference 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
Grazed 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
Modified
Transformed
Replaced/ managed or removed
Residual
Replaced /adventive
VAST
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 native 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, Transect 1 (ex-comp 8b, 9a, 9b) Reference pre-European: Sydney Blue Gum High Forest
• 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
Lessons: Resources needed at site level
Lessons: site vs landscape
1. Constrain assessments to soil landscape units because this approximates to land manager’s
2. Must account for major natural events e.g. flood, fire, cyclone3. Remote sensing is only part of the solution –
a) Some measures of remote sensing e.g. greenness of crown health may not be directly related to vegetation condition
4. Tracking outcomes of management interventions a) Must collect on-ground data and have a model for linking change to datasets
derived from remote sensing
Lessons: What is the baseline?
Zero/constant baseline (e.g. environmental planting)
A measure or estimate (red line) that would have occurred in the absence of an activity/intervention e.g.
Resp
onse
va
riabl
e/s
Time
Start ofactivity/
intervention
Time
Varying baseline (e.g. environmental watering)
Resp
onse
va
riabl
e/s
Single intervention & climatic variability
BaselineResponse to activity/ intervention
Indicator 13: Overstorey height
Indicator 4: ground water
Lessons: Importance of dynamics
Assume rainfall is main driver of natural 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
Seasonal rainfall anomaly (Lat -32.404, Long 152.496)
1901
1904
1907
1910
1913
1916
1919
1922
1925
1928
1931
1934
1937
1940
1943
1946
1949
1952
1955
1958
1961
1964
1967
1970
1973
1976
1979
1982
1985
1988
1991
1994
1997
2000
2003
2006
2009
2012
-2-1.5
-1-0.5
00.5
11.5
22.5
Spring
1901
1904
1907
1910
1913
1916
1919
1922
1925
1928
1931
1934
1937
1940
1943
1946
1949
1952
1955
1958
1961
1964
1967
1970
1973
1976
1979
1982
1985
1988
1991
1994
1997
2000
2003
2006
2009
2012
-3-2-1012345
Winter
1901
1904
1907
1910
1913
1916
1919
1922
1925
1928
1931
1934
1937
1940
1943
1946
1949
1952
1955
1958
1961
1964
1967
1970
1973
1976
1979
1982
1985
1988
1991
1994
1997
2000
2003
2006
2009
2012
-3-2-10123456
Autumn
1901
1904
1907
1910
1913
1916
1919
1922
1925
1928
1931
1934
1937
1940
1943
1946
1949
1952
1955
1958
1961
1964
1967
1970
1973
1976
1979
1982
1985
1988
1991
1994
1997
2000
2003
2006
2009
2012
-2-1.5
-1-0.5
00.5
11.5
22.5
3
Summer
Source: BOM
Conclusions
• A framework that helps decision makers assess and report change at sites and landscapes due to human management and natural drivers
• A tool (i.e. VAST) for assisting in reporting on the current status of Australia’s vegetation types - used in– National State of the Environment Report (2011)
• An accounting tool (VAST-2) for reporting change and trend in the transformation of vegetation types at sites - used in– National State of the Forests Report (2013) – Regional Environmental Accounts (Wentworth Group of Concerned
Scientists 2015)
More info & Acknowledgements
More informationhttp://www.vasttransformations.com/http://portal.tern.org.au/searchhttp://aceas-data.science.uq.edu.au/portal/
Acknowledgements• Many public and private land managers, land management agencies, consultants
and researchers have assisted in the development of VAST & VAST-2