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Framework for assessing and reporting resilience of native vegetation

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A framework is presented that is relevant to all terrestrial ecosystems and their modification states. Unpinning the framework is the tool's ability to track change and trends based on assessing effects of land management regimes. Effects of these regimes on criteria & indicators of function, structure and composition are scored using criteria and indicators. Changes in condition, resilience and transformation are assessed relative to fully natural a reference state for each plant community. Assessments are constrained to soil landscape units because this approximates to land manager’s use and management of the landscape. The framework helps decision makers assess and report change at sites and landscapes due to human management and natural drivers.

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Framework for assessing and reporting resilience of native vegetation

  1. 1. Framework for assessing and reporting resilience of native vegetation Richard Thackway Lecture presented as part of the Fenner School of Environment and Society, ANU’s undergraduate course, ENVS3041 Managing Forested Landscapes 8 March 2017
  2. 2. 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
  3. 3. 1925 Occupation Relaxation Anthropogenic change Net benefit time 1900 20251950 Reference changeinvegetation indicatororindex 1850 1875 1975 2000 VAST classes A model of ecosystem change (causes & effects)
  4. 4. 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) 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
  5. 5. Change over space Thackway & Lesslie (2008) Environmental Management, 42, 572-90 NB: Input dataset biophysical naturalness reclassified using VAST framework / replaced / unmodified VAST 2009 Native
  6. 6. How to account for changes in native veg type, extent and condition? LMP deliberately &/or unintentionally do this by: • Modifying • Removing and replacing • Enhancing • Restoring • Maintaining • Improving * * Natural disturbances Function Structure & Composition LMP = land management practices
  7. 7. Tracking change and trends based assessing effects of land management regimes Effects of regimes on criteria & indicators of function, structure and composition Examples No active interventions Biodiversity protection, minimal use Harvest products Biomass, fibre, flowers, fruit and nuts Enhance or improve Rehydrate soils, control invasive species, reestablish a fire regime, seed hays Extirpate or remove Overgrazing, intensive cropping, pasture improvement, removal of fire regime, draining wetlands Reconstruct Revegetate, rehydrate soils, stabilize soil Thackway and Freudenberger (2016)
  8. 8. A framework that is relevant to all terrestrial ecosystems and their modification states
  9. 9. Source: http://www.headlinesciencenow.com/2013/11/29/cracking-chicken-egg-mystery/ Response variables (effects) Management regimes
  10. 10. VAST I: Unmodified /residual native Photographs: Richard Thackway & Ross Peacock
  11. 11. VAST II: Modified native Photographs: Richard Thackway
  12. 12. VAST III: Transformed native Photographs: Richard Thackway
  13. 13. VAST IV: Replaced & adventive Photograph: Richard Thackway
  14. 14. VAST V: Replaced & managed Photographs: Richard Thackway
  15. 15. VAST VI: Replaced & removed Photographs: Richard Thackway
  16. 16. A framework for assessing and reporting vegetation resilience (space and time)
  17. 17. Understanding ecosystem change over time Indigenous land management First explorers Grazing Degreeof modification Logging Cropping Site 1 Site 2 Site 3 Time Reference state Long term rainfall Long term disturbance e.g. wildfire, cyclones Revegetation The same ecosystem e.g. eucalypt open forest with different management histories t2t1 t3
  18. 18. Creating systematic and comprehensive chronology to assess where, when and how landscapes are transformed relative to a reference LU = Land Use, LMP = Land Management Practices VAST Diagnostic attributes Time
  19. 19. Components (3) Function Regenerativecapacity Vegetationstructure Species Composition
  20. 20. Components (3) Criteria (10) Function Regenerativecapacity Fire regime Soil hydrology Soil physical state Soil nutrient state Soil biological state Reproductive potential Vegetationstructure Overstorey structure Understorey structure Species Composition Overstorey composition Understorey composition
  21. 21. Components (3) Criteria (10) Description of loss or gain relative to pre settlement indicator reference state (22) Function 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 – 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 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
  22. 22. 1 3 10 22 Diagnostic attributes Vegetation Transformation score Attribute groups 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 VAST-2 – benchmark scoring of the effects of use and management of native veg (indicators) over time
  23. 23. 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
  24. 24. 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
  25. 25. 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)
  26. 26. Components (Level 2) Criteria (Level 3) Description of loss or gain relative to pre settlement indicator reference state (Level 4)Regenerativecapacity Function Natural disturbance Change in the area /size of events Change in the number of events 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 – 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 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. 27. Case study 1 Phillip Island, South Pacific
  28. 28. Phillip Island Google earth
  29. 29. Photograph: Peter Coyne 1740 1906 Phillip Island, South Pacific Photograph: State Library NSW: JW Beattie By 1860 already denuded (Removed and replaced: VAST VI) Reference (Unmodified: VAST I) Pine – Hardwood Subtropical Rainforest
  30. 30. 1981 2008 Photographs: Peter Coyne (Adventive: VAST IV) (Adventive: VAST IV)
  31. 31. year score% Pine – Hardwood Subtropical Rainforest, Phillip Island, Sth Pacific Pigs released Uninhabited island Pigs died out Goats and rabbits released Goats died out Rabbits eradicated Rabbit control commenced Commenced passive & active restoration. Minimal ecological monitoring
  32. 32. Case study 2 Bridge Hill Ridge, Myall Lakes, NSW
  33. 33. Sand mining path Bridge Hill Ridge Sydney Newcastle Smiths Lake Restoration following mineral sand mining
  34. 34. Topsoil briefly stockpiled <10 days Timber harvested and remaining trees and vegetation removed 1974 (0 years old) Photographs: Barry Fox (Removed and replaced: VAST VI)
  35. 35. Sand sprayed and dried and re-shaped as a contoured dune Sandmining Dredge Original Eucalypt open forest Dredge Pond Smiths Lake Dredge Pond 1974 (0 years old) Photographs: Barry Fox (Removed and replaced: VAST VI)
  36. 36. 1974-75 (0-6 months old) Topsoil spread over reshaped sand dune Sorghum cover crop planted 1974 (One month old) 1975 (< 6 months old) Photograph: Barry Fox (Removed and replaced: VAST VI) (Removed and managed: VAST V)
  37. 37. 2014 (39 years later) Photographs: Richard Thackway(Unmodified: VAST II)
  38. 38. Function (Regenerative capacity) Criteria
  39. 39. Criteria Vegetation structure
  40. 40. Criteria Species composition
  41. 41. Predictions of mature forest (Bunning’s Enquiry 1974)* * 50 yrs 2035, 80 yrs 2055, 100 yrs 2074
  42. 42. • 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
  43. 43. 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, cyclone 3. 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
  44. 44. 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
  45. 45. Agro-climatic regions Peer reviewed sites Applications of the framework
  46. 46. Transformationscore Years 1800 2016 Reference Relevance to developing scenarios for future landscape transformation Modified Transformed Replaced/ managed Residual Replaced/ adventive VAST Classes 1850 19501900 2000 2050 2100 Replaced/ removed Baseline Classes can be modelled as extent and condition Extentnative
  47. 47. 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)
  48. 48. More info & Acknowledgements More information http://www.vasttransformations.com/ http://portal.tern.org.au/search http://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

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