Predicting Extinction Risk

Predicting Extinction Risk

1. threats to biodiversity

   • anthropogenic drivers
     • biological resource use (fishing, harvesting etc)
     • invasives, problem spp, hybridisation, disease
     • pollution (metals, nutrients, POPs, litter)
     • climate change and severe weather
     • habitat destruction/degredation
       • residential and commercial development
       • agriculture, aquaculture, forestry
       • energy production and mining
       • transportation and service corridors (incl. power lines)
       • human intrusions and disturbances (eg war, hikers etc)
       • natural systems modifications (dams, fire regimes, etc)
   • natural drivers (still exacerbated by people)
     • geological events
     • other threats (eg meteors)

2. to maintain current human population at current standard of living we need the resources of 1.4 earths; yet people keep breeding and still aspire to a higher standard of living

3. life history

   • large, K-selected spp more at risk from deterministic extinction (declining population paradigm) because they are not able to handle extra mortality
   • small, r-selected spp more at risk from small population paradigm (stochastic extinction) cause they are subjuect to large popuklation fluctuations so can fall into extinction vortex if N is too small

4. taxon cycle (spp have a "life-cycle" vs younger plants more at risk of extinction

5. specialists at risk (diets and habitats), spp that need multiple habitats to complete their life histories (eg migrants)

6. close mutalisms (e.g. replying on a single pollinator)

7. extinction cascades: loss of a keystone spp can trigger extinctions of dependent spp

8. allee effect: an individuals fitness suffers at low population densities. eg to breed (passenger pigeons) to hunt in packs (wild dogs). spp that aggregate are more susceptible to extinciton

9. vagility

   • pros:
   • cons: