River dolphins as indicators of ecosystem degradation in large tropical rivers

1. River dolphins as indicators of ecosystem degradation in large tropical rivers Ecological Indicators 23 (2012) 19-26 Presented by E. Johnson Authors: Catalina Gomez-Salazar Marta Coll Hal Whitehead Pink River Dolphin Iniageoffrensis TucuxiSotaliafluviatilis

2. Introduction: Human Stressors • Water Quantity • Water Quality • Habitat Modification • Exploitation of Species • Climate Change • Introduced Species

3. Introduction: Monitoring • Essential: • Conservation priorities and strategies • Scientific support for policies • Restoring ecosystem services • Expensive and labor intensive

4. Introduction: Indicator Species • Alternative – Reliable Indicator Species • Top predators ideal • Concentrated in biodiversity hotspots • Sensitive to ecosystem degradation • Highest sightings – low human populations/strong protection

5. Review of Literature: • Karr, J.R., Chu, E.W. Island Press, 1999. • Importance and efficacy of biological data in resource management decision-making.

6. Review of Literature: • Vörösmarty, C.J., McIntyre, P.B., Gessner, M.O., Dudgeon, D., Prusevich, A., Green, P., Glidden, S., Bunn, S.E., Sullivan, C.A., Liermann, C.R. , Nature , 2010. • World’s freshwater resources critical to human water security and biodiversity

7. Review of Literature: • Sergio, F., Caro, T., Brown, D., Clucas, B., Hunter, J., Ketchum, J., McHugh, K., Hiraldo, F., Annual Review of Ecological Systems, 2008. • Top predators promote species richness and are effective sentinel and flagship species.

8. Review of Literature: • Tavera, G., Aliaga-Rossel, E., Van Damme, P.A., Crespo, A., The Action Plan for South American River Dolphins 2010–2020, 2010. • South American River Dolphins: threats to survival, protective measures.

9. Problem: • To investigate whether river dolphins can indicate freshwater ecosystem degradation at a regional scale.

10. Methodology: Study Area

11. Methodology: Human Stressors • Human Stressor Index • Water quality degradation • Habitat modification • Exploitation of species • Human population size (proxy)

12. Methodology: Stressor Impacts

13. Methodology: Impact Indices

14. Methodology: Overall Risk

15. Methodology: Dolphins • Dolphin Abundance Measures: • Sighting Rates – dolphins/km-1 • Density – Dolphins/km2 • Mean group size

16. Methodology: Correlation • Spearman’s Rank Correlation • Null hypothesis

17. Methodology: Spearman’s Rank

18. Discussion: • Human Stressors Indices • Stressors will increase • Density estimates and sightings • Group size – little correlation

19. Discussion: • Advantages of river dolphins as indicators • Distribution • Turbidity • Ease of data collection • Long-lived • Sentinel species • Charismatic – flagship species

20. Conclusion: • River Dolphins are good ecological indicators of freshwater degradation; both density estimates and sightings

21. Next Steps: • Research use of river dolphins in Asia • Find a mentor working with river dolphins

22. Questions?