David Keith_Risk assessment of Australian ecosystems
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David Keith_Risk assessment of Australian ecosystems

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David Keith_Risk assessment of Australian ecosystems David Keith_Risk assessment of Australian ecosystems Presentation Transcript

  • Risk assessment of Australian ecosystems David Keith & IUCN Ecosystem Red List Working Group
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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)
  • 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)
  • 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)
  • 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
  • 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
  • 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
  • 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)
  • Better environmental reporting for Australian ecosystems
  • 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
  • Thank you