David Keith_Risk assessment of Australian ecosystems

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David Keith_Risk assessment of Australian ecosystems

  1. 1. Risk assessment of Australian ecosystems David Keith & IUCN Ecosystem Red List Working Group
  2. 2. Status of Australian ecosystems - Why we need to know• International obligations• Legislative responsibilities – an informed Australian public• Evidence-based decision making & priorities – env’t investment, trade-offs• Responses to ecosystem management• Horizon scanning
  3. 3. A framework for synthesis - risk assessment of ecosystems• Red List of Species – International standard for assessing risks to species – Generality, data-efficient, effective communication• No analogue for assessing risks to higher levels of biodiversity
  4. 4. Red List criteria for Species A. Decline in # mature individuals over 10 yrs / 3 generations “quantitative” categories QUANTITATIVE and / or Vulnerable THRESHOLDS B. Small geographic distributionAND fragmented/decline/fluctuation Endangered and / or Critically Endangered C. Small populationAND fragmented/decline/fluctuation and / orD. Very small population distribution “qualitative” categories AND serious plausible threats and / or Near Threatened E. Risk of extinction over Least Concern next 3 gens/100 yrs Data Deficient Not Evaluated
  5. 5. Assessing risks to ecosystemsEcosystem concept(4 defining features, Tansley 1935)1. Characteristic assemblage of biota2. Associated physical environment3. Processes & interactions Risks between components – among biota – between biota & environment4. Spatial extent
  6. 6. Towards a Red List of ecosystems Ecosystem collapse - transformation, loss of defining features Risk assessment - probability of collapse over a given time frame Semi-arid rangelands (Westoby et al. 1989) – desertification ?Transient herbivore activity maintains Intense sustained herbivore activitysoil crust & perennial plant cover, destabilises soil surface, degraded soillimiting soil erosion & degradation inhibits recruitment of perennial plants
  7. 7. Threatening processes Assessing Ecosystem distribution Ecosystem function Ecosystem Change A Declining C Environmt’l Risk model distribution degradation for ecosystems • threats to defining features (distribution, Risk of loss of characteristic biota & function) native biota • multiple mechanisms (causes of threat) B Small D Altered biotic processes • 4 symptoms (ofdistribution decline) = 4 criteria • plus one overarching E Quantitative risk analysis criterion (probability of collapse) Threatening processes
  8. 8. A. Decline in distribution – criteria & thresholds A1 A2 A3 Current Future Historic Status (last 50 yrs) (next 50 yrs) (since c. 1750) CR ≥80% ≥80% ≥90% EN ≥50% ≥50% ≥70% VU ≥30% ≥30% ≥50% NT almost 30% almost 30% almost 50% LC <30% <30% <50% Change in wetland distribution 1960 – 2000 Contraction 1 Expansion 2 4 8 6 7 3 9 10 5 10% net increase in Remained woodland Swamp to woodland distribution (Keith et al. 2010) Remained swamp Woodland to swamp 0.5 0 0.5 1 Kilometres Criterion A = Least Concern
  9. 9. C & D: Steps for assessing functional decline 1. Select one/more variables representing ecosystem function(s) 2. Estimate ‘collapsed state’ – what value of the functional variable indicates ecosystem collapse? 3. Estimate initial state – what is the past value of the variable, e.g. 50 yrs ago? 4. Estimate current state – what is the current value of the variable? 5. Calculate range-standardised decline & compare with thresholds
  10. 10. Selecting variables for assessing functional declines (C & D)Must represent key ecosystem driver orthreatening process• Proximal variables better than indirect ones• Ecosystem-specific variables better than generic ones• Sensitive variables better than insensitive ones• Choice informed by cause/effect process models (cause-effect diagrammatic summaries of ecosystem dynamics)
  11. 11. Selecting functional variables for ecosystem risk assessment Mac Nally et al. 2011 S. Cunningham Salient functional variablesRiver Red Gum Forests • stream flow (criterion C) • foliage cover (criterion D)
  12. 12. Selecting functional variables for ecosystem risk assessment Herbivorous Predatory fishCoral reefs Algae fish Coral reef Fishing Storms Coral diseases Water temperature Pollute & chemistry d runoff Human population Climate change Salient functional variables • sea surface temperature, ocean acidity (criterion C) • coral cover, reef rugosity (criterion D)
  13. 13. Estimating relative severity of functional decline 1. Select functional variable (mean ann max river hgt) 2. Estimate ‘collapse state’ (450-500 cm)Max River Hgt >700cm 3. Estimate initial state (712 cm) 4. Estimate current state (619 cm) 5. Calculate range-standardised decline 100*(observed)/(collapsed) = VULNERABLE 50 yrs) Criterion C1 = 35-44% (past Mean maximum river height (cm) 301000 Average max 10 yr mean average max Series1 Murray River Inflow (GL/yr) 25 900 Series3 800 20 700Max river hgt 500 cm 600 15 500 400 10 300 5 200 100 0 0 19601900 1970 1920 1980 1940 1990 1960 2000 1980 2000 2010Max river hgt <400 cm Year Year
  14. 14. Risk assessment outcomes- level of risk, causes of decline LC A EN-CR contracting future distribution LC B EN EN LC LC C EN-CR declining bioclimatic habitat suitability DD DD D Risk assessment implicates DD E DD climate change as greatest DD threat  adaptation strategies
  15. 15. What can risk assessment tell us about the status of biodiversity? New Zealand Granite Gravel Fields: LC Caribbean Reefs: EN-CR Murray River Red Gum Murray-Darling Wetlands: EN-CR Forests: VU Coolibah-Blackbox WL: EN Madagascan Tapia Forest: ENVenezuelan Tepui: LC Cape Flats Fynbos: CR Alaskan Kelp Forests: EN-CR Sth Aust Seagrass Meadows: EN Coorong Lagoons: CR European Reedbeds: VU
  16. 16. Data requirements for ecosystem risk assessmentSpatial data• Ecosystem distribution (derivatives of landcover types, soil types, terrain)• Change in distribution & function (time series of landcover, biomass, hydrology, productivity, disturbance metrics)Plot/site data• Species composition (ecosystem description, classification)• Ecosystem processes (time series of species composition, abundance, biomass, productivity, hydrology, edaphic, climate)
  17. 17. Better environmental reporting for Australian ecosystems
  18. 18. ACEAS working group - risk assessment of Australian ecosystemsObjectives• Train Aust & NZ practitioners in Red List assessment methods• Review current listing procedures for ecosystems/communities cf. new international standard• Review data requirements for risk assessment and capacity of TERN to provide (LTERN, AusCover)• Develop detailed risk assessments for selected Aust & NZ ecosystems
  19. 19. Thank you

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