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River dolphins as indicators of ecosystem degradation in large tropical rivers

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 Inia geoffrensis. Tucuxi Sotalia fluviatilis.

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River dolphins as indicators of ecosystem degradation in large tropical rivers

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  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?

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