1. Andrew Gonzalez Canada Research Chair Department of Biology Understanding the impacts of extinction: the next step for biodiversity research

2. 2 “Changes in biodiversity due to human activities were more rapid in the past 50 years than at any time in human history, and the drivers of change…show no evidence of declining over time, or are increasing in intensity.” Key Message Extinction rates are 100-1000 times higher than the background rate

3. 3 MES: Biodiversity Synthesis In ~15 yrs of BD research we have learnt a great deal. BD loss has happened, is ongoing. BD matters for ecosystem functioning. A deeper understanding of of BD loss is required--more science. High uncertainty Conflicting human and ecological needs.

4. 4 “A mismatch exists between the dynamics of changes in natural systems and human responses to those changes.” pg21 MABS Key Issue for future biodiversity research

5. 5 Functional Effects of Biodiversity Loss Characteristics: 1.Ignorance of mechanism 2.Potential catastrophic costs 3.Relatively modest benefits 4.Low subjective probability 5. Internal experience of costs 6.External transfer of benefits 7.Collective risk 8.Latency (lagged effects) 9.Irreversibility

6. 6 Hypothesis: Does diversity loss affect ecosystem function? Anthropogenic Disturbance EcosystemAnthropogenic Disturbance Ecosystem Function Extinction Is Biodiversity Loss a Component of Global Change? ? Ecosystem Function Diversity gradients ?

7. 7 Simple 'models' proposed (circa 1993) for the relation between diversity and ecosystem function "Redundancy" "Complementarity" Ecological function diversity Articulating the Hypothesis

8. 8 Experiments have been performed at small spatial and temporal scales and assume way the ‘dynamics’ of extinction. Experimental Evidence Cedar Creek, Minnesota

9. 9 Hypothesis: Extinctions are a consequence of disturbance and can amplify the effects of disturbance. Ecosystem Function Diversity Getting Real Anthropogenic Disturbance Ecosystem Anthropogenic Disturbance Function Extinction ?

10. 10 Biodiversity Loss: why response mismatches? Characteristics: 1.Ignorance of mechanism 2.Potential catastrophic costs 3.Relatively modest benefits 4.Low subjective probability 5. Internal experience of costs 6.External transfer of benefits 7.Collective risk 8.Latency (lagged effects) 9.Irreversibility

11. 11 Example of a response mismatch: “Extinction debts” “Extinction debt”: the difference between the initial and final levels of diversity attained long after the initial disturbance. Current experimental protocols based on “random species assembly” do not mimic extinction. Extinction is a highly nonlinear process (perhaps cascading) with inherent response delays.

12. 12 Studying the lagged effects of extinction: habitat loss 50cm 20cm² Control Fragments 50cm 200cm² A complementary ‘dynamic’ approach: Allows the study of the extinction process Replicated experimental landscapes of natural (micro) ecosystems

13. 13 An Example of an Extinction ‘Debt’ Fragments Controls Time after fragmentation 0 1 2 3 4 5 6 7 8 9 024681012 Secondary biomass (mg) <68% 2 7 12 17 22 27 024681012 Species richness (# spp) <40% Species richness Secondary biomass

14. 14 Characteristics: 1.Ignorance of mechanism 2.Potential catastrophic costs 3.Relatively modest benefits 4.Low subjective probability 5. Internal experience of costs 6.External transfer of benefits 7.Collective risk 8.Latency (lagged effects) 9.Irreversibility “A mismatch exists between the dynamics of changes in natural systems and human responses to those changes.” pg21 MABS

15. 15 It is imperative that we study the dynamics of extinction within the context of anthropogenic disturbance: this is possible but new approaches are required. Without this knowledge it will be difficult to mitigate the functional consequences of future extinctions so clearly articulated in the Millenium Assessment. Conclusions Significant progress in biodiversity research to date, but still only a poor understanding of the functional effects of extinction.

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