Assessing and reporting resilience of native vegetation using metrics of structure, composition and function
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The effects of contemporary and previous land management practices are reflected in the present-day condition of native vegetation. In order to properly manage land for productive use or to restore it to its 'natural' condition, it is important to know the changes that have taken place to the use of the land, and the cumulative effect of those changes. Assessing and reporting the resilience of native vegetation using metrics of structure, composition and function is discussed. The system, VAST-2, has been developed in the Australian context, where land management was relatively unchanged for some tens of thousands of years prior to European settlers who arrived some hundred years hence. This reference state provides a structure in which to compile, interpret and sequence data gathered in the past about changes in management practices and the effects of these practices on the condition of native plant communities. Early settlers and subsequent land managers have modified and fragmented the native vegetation thereby transforming many landscapes.
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Assessing and reporting resilience of native vegetation using metrics of structure, composition and function
- 1. Assessing and reporting resilience of native vegetation using metrics of structure, composition and function Richard Thackway Macquarie University Biology Department Seminar 22 April 2015
- 2. Outline ⢠How the land use modifies native vegetation ⢠Links between management and ecosystem services ⢠VAST-2 methodology â Detailed chronology of causes and effects â Criteria and indicators of structure, composition and function â Some concepts and definitions â Analytical framework ⢠Case studies ⢠Lessons ⢠Where to from here ⢠Conclusions and more information
- 3. Every vegetated landscape has been effected by land management practices since European settlement
- 4. Reference state: ⢠Grassy woodland Transformation state: ⢠Modified (VAST II) Land use: ⢠Aboriginal land Current management goal: ⢠Establish an appropriate fire regime Climate zone: ⢠Tropical Locality: ⢠Robinson River, NT 2006
- 5. Reference state: ⢠Complex Notophyll Vine Forest Transformation state: ⢠Transformed (VAST II) Land use: ⢠Conservation reserve Current management goal: ⢠Control and remove weeds Climate zone: ⢠Sub-tropical Locality: ⢠Lismore, NSW 2006 20092009
- 6. Reference state: ⢠Grassy woodland Transformation state: ⢠Adventive (VAST IV) Land use: ⢠Electricity easement Current management goal: ⢠Provide open space Climate zone: ⢠Temperate Locality: ⢠Canberra, ACT 2010
- 7. Reference state: ⢠Grassy shrubland Transformation state: ⢠Transformed (VAST III) Land use: ⢠Conservation reserve Current management goal: ⢠Establish 30% ground cover Climate zone: ⢠Arid Locality: ⢠Alice Springs, NT 2006 2009
- 8. Most tools for assessing veg condition only produce a snapshot and not change over time
- 9. VAST = Vegetation Assets States and Transitions NVIS = National Vegetation Information System VIVIVIIIIII0 Native vegetation cover Non-native vegetation cover Increasing modification caused by use and management Transitions = trend Vegetation thresholds Reference for each veg type (NVIS) VAST - A framework for assessing & reporting native 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 Resilience threshold
- 10. 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
- 11. Reporting change in condition using Vegetation Types (NVIS/MVG), and vegetation condition (VAST) Source: ABARES 2013 Veg type (NVIS/MVG) NVIS: National Vegetation Information System MVG: Major Vegetation Groups VAST * * bioregion
- 12. To understand landscape transformation we to understand why land managers change the structure, composition and function of native vegetation
- 13. Historic goals of land managers over time Values and decisions matrix: ⢠Social ⢠Economic ⢠Environmental Intensification Degradation? Time State @ t1 State @ t2 State @ t3 Development
- 14. 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 LMP are used to change ecological function to derive multiple benefits (ecosystem services) t1 t2 t3 Time State@t1 State@t2 State@t3
- 15. Current & future goals of land managers Values and decisions matrix: ⢠Social ⢠Economic ⢠Environmental Extensification Restoration State @ t1 Regeneration State @ t2 State @ t3
- 16. 1925 Occupation Relaxation Anthropogenic change âNet benefitâ time 1900 20251950 Reference changeinvegetation indicatororindex 1850 1875 1975 2000 VAST-2 model of transformation of native vegetation VAST classes
- 17. Concepts and definitions ⢠Resilience = the capacity of an plant community to recover toward a reference state following a change/s in land management ⢠Change in condition of a plant community (type) is due to effects of land management practices: â Structure â Composition â Regenerative capacity ⢠Transformation = changes in vegetation condition over time ⢠Condition, resilience and transformation are assessed relative to a fully natural Reference state Vegetation condition
- 18. Based on Cannon (1987) Baseline for assessing resilience: Indigenous peoples first contact with explorers Based on Cannon (1987), Readers Digest. Plotted using IBRA regions
- 19. How do land managers modify structure, composition & function (i.e. resilience) over time? LMP that focus on soil LMP that focus on native vegetation Regenerative capacity/ function Vegetation structure & Species composition 1. Soil hydrological status 2. Soil physical status 3. Soil chemical status 4. Soil biological status 5. Fire regime 6. Reproductive potential 7. Overstorey structure 8. Understorey structure 9. Overstorey composition 10. Understorey composition LMP = Land Management Practices Focussing on 10 key criteria
- 20. Common interventions designed to influence structure, composition & function i.e. resilience Various interventions: Land management practices (LMP) are used to influence ecological building blocks at sites and landscapes by: ⢠Modifying ⌠⢠Removing and replacing ⌠⢠Enhancing ⌠⢠Restoring ⌠⢠Maintaining ⌠⢠Improving ⌠Various purposes: To achieve the desired mix of ecosystem services (space & time)
- 21. VAST-2 is an accounting system for assessing the transformation of native vegetation LU = Land Use, LMP = Land Management Practices VAST Diagnostic attributes Time
- 22. Aim of VAST-2 at sites and landscapes Indigenous land management First explorers Grazing Degreeof resilience/condition Logging Cropping Site 1 Site 2 Site 3 Time Reference state Long term rainfall Long term disturbance e.g. wildfire, cyclones Revegetation VAST classes Weeds Ferals
- 23. How does VAST-2 use metrics to assess and report resilience/condition of native vegetation?
- 24. Generate total indices for âtransformation siteâ 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 âtransformation siteâ relative to the âreference siteâ. 0 = major change; 1 = no change Derive weighted indices for the âtransformation siteâ 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
- 25. Approximate year Source: Year LU & LMP Source: LU & LMP Effects of land use and management on criteria and indicators of vegetation condition Source: Effects 1800 1840 2015 Establish a chronology of data and information of causes and effects /observed & measured responses Pre-contact First contact Current year LU = Land Use, LMP = Land Management Practices NB: Accuracy of each observation and measurement is important
- 26. Components (3) Criteria (10) Description of loss or gain relative to pre settlement indicator reference state (22)Regenerativecapacity 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 availability Change 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 â rundown (deficiency) relative to soil fertility Nutrient stress â 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 Vegetationstructure 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 Composition 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
- 27. 1 3 10 22 Components (3) Vegetation Transformation Score (1) Criteria (10) Vegetation Structure (27%) Overstorey (3) Understorey (3) Species Composition (18%) (2) UnderstoreyOverstorey (2) Regenerative Capacity (55%) Fire (2) Reprod potent (2) Soil Hydrology (2) Biology (2) Nutrients (2) Structure (2) Indicators (22) VAST-2 â benchmark scoring of the effects of use and management of native veg (indicators) over time
- 28. Importance of dynamics Assume rainfall is main driver of natural system dynamics ⢠Period 1900 - 2014 ⢠Average seasonal rainfall (summer, autumn, âŚ) ⢠Rainfall anomaly is calculated above and below the mean ⢠Two year running trend line fitted
- 29. Seasonal rainfall anomaly (Lat -32.404, Long 152.496) -2 -1 0 1 2 3 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 Spring -3 -2 -1 0 1 2 3 4 5 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 Winter -4 -2 0 2 4 6 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 Autumn -2 -1 0 1 2 3 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 Summer Source: BOM
- 30. ⢠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, modelled average rainfall 1900-2014 ⢠Observed interactions e.g. rabbits, sheep and drought ⢠Observations and quantitative measures of effects of LMP ⢠Include written, oral, artistic, photographic, long-term ecological monitoring sites and remote sensing Resources needed for each site
- 31. Certainty level standards used to compile historic record Certainty level standards Spatial precision (Scale) Temporal precision (Year of observation) Attribute accuracy (Land use, land management practices, effects on condition) HIGH "Definiteâ Reliable direct quantitative data. Code: 1 Reliable direct quantitative data. Code: 4 Reliable direct quantitative data. Code: 7 MEDIUM "Probable " Direct (with qualifications) or strong indirect data. Code: 2 Direct (with qualifications) or strong indirect data. Code: 5 Direct (with qualifications) or strong indirect data. Code: 8 LOW "Possible" Limited qualitative and possibly contradictory observations. More data needed. Code: 3 Limited qualitative and possibly contradictory observations. More data needed. Code: 6 Limited qualitative and possibly contradictory observations. More data needed. Code: 9
- 32. Reliability levels of attribute sources Quadrat or pixel Land unit Land system Sub-bioregion Bioregion Certainty levels Coarse Fine Low Low Medium Medium High Sources of information Granularity of information
- 33. Assumptions Changes in LU & LMP â result in measurable and predictable changes in structure, floristics & regen capacity â can be consistently and reliably differentiated from natural events â have or can be adequately and reliably documented over time Sequential responses in veg structure, floristics & regen capacity can be discovered, unpacked and scored over time Ratings and weightings are ecologically meaningful
- 35. Coastal Eucalypt Angophora open forest, Myall Lakes, NSW
- 36. Salmon gum woodland, Great Western Woodlands, WA
- 37. Chenopod shrubland, Koonamore Station, SA
- 38. Wanaringa Brigalow woodland, Taroom Shire, Qld
- 39. Can the results and the system be used by decision makers and land managers to influence future landscapes?
- 40. Transformationscore Years 1800 2012 Reference Futures landscape - strategic regeneration, revegetation & restoration Modified Transformed Replaced/ managed Residual Replaced/ adventive VAST Classes 1850 19501900 2000 2050 2100 Replaced/ removed
- 41. Predictions of mature forest (Bunningâs Enquiry 1974) Bridge Hill Ridge- post mining restoration X = 2034 Y = 2054 Z = 2074 X Y Z
- 42. Predictions of mature forest (Bunningâs Enquiry 1974) Bridge Hill Ridge- post mining restoration X = 2034 Y = 2054 Z = 2074 X Y Z
- 43. Components (3) Criteria (10) Description of loss or gain relative to pre settlement indicator reference state (22)Regenerativecapacity 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 availability Change 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 â rundown (deficiency) relative to soil fertility Nutrient stress â 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 Vegetationstructure 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 Composition 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
- 44. Lessons site vs. landscape 1. Constrain assessments to soil landscape units because this approximates land managerâs interventions 2. Must account for natural dynamics e.g. flood, fire, cyclone 3. Remote sensing is only part of the solution â a) Some measures of remote sensing e.g. greenness of tree crowns may not be directly related to vegetation condition 4. Tracking outcomes of management interventions using remote sensing a) e.g. environmental plantings and environmental watering requires on- ground collection of data to calibrate and validate spatial and multi- temporal imagery b) Only populate criteria and indicators once imagery has been validated
- 45. Conclusions ⢠VAST and VAST-2: ď Provides an accounting tool for reporting change and trend in the condition of plant communities ď Helps with telling the resilience story in landscape transformation ď Provides a system for synthesizing diverse source and types of information (quantitative and qualitative) ď Values equally land managers and ecologists because they both contribute essential data and information ď Enables decision-makers to better understand complex ecosystem transformations such as degradation, restoration and regeneration.
- 46. âTelling the transformation storyâ Residual/ unmodified Modified Transformed Adventive Replaced and managed Organ Pipes National Park, Vic â ex cropping paddock Pathways of landscape transformation reflect choices and drivers VAST classes
- 49. More info & Acknowledgements More information http://www.vasttransformations.com/ http://portal.tern.org.au/search http://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