The future biogeography of freshwater fishes


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Presented by Julian D. Olden at the International Congress of Ecology (2010)

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The future biogeography of freshwater fishes

  1. 1. Species invasions, environmental change andthe future biogeography of freshwater fishes Julian D. Olden University of Washington, Seattle, Washington, USA
  2. 2. Water – The lifeline of the biosphereFreshwater ecosystems touch nearly all aspects of human society: – acting as centers of organization within the landscape – providing countless cultural and ecological services – supporting a rich diversity of biological life Freshwater fishes represent almost one-quarter of the global vertebrate diversity
  3. 3. The Freshwater Fish Crisis• Freshwater ecosystems are almost always embedded in a Freshwater biodiversity in peril matrix of human use, dependence, and modification Freshwater Have fish fishes in crisis• Conflicts between human had their chips? demands and ecosystem needs for water currently are growing• 37% of evaluated freshwater fish species are considered Sink or swim: threatened with global One third of Europe’s Vanishing freshwater fish face extinction extinction (IUCN 2009) freshwater fishes
  4. 4. Threats to Freshwater FishesHabitat loss Invasive species PollutionOver-exploitation Disease Climate change
  5. 5. Biogeography of Freshwater Fishes• Fishes are uniquely constrained because their ability to respond to environmental change is limited to movement defined by the connectivity of water
  6. 6. Biogeographic barriers in fresh waters Global Fauna Oceans, mountains Continental Fauna Catchment divides Basin Fauna Waterfalls, cascades Local Species Pool Wallace (1876)
  7. 7. Glaciations shaped faunal exchangeGlacial Refugia Beringian (13%) Banff-Jasper (1%) Cascadia (4%) Missourian (20%) Mississippian (85%) Atlantic (7%) Crossman and McAllister (1986)
  8. 8. Catchment divides shaped fish faunas• River basins in North America that escaped glaciation tend to have more unique fish faunas• Catchment divides have been a formidable barrier to fish movement
  9. 9. Biogeographic barriers in fresh waters Global Fauna Oceans, mountains Continental Fauna Catchment divides Basin Fauna • The hierarchy of movement Waterfalls, cascades barriers have resulted in river Local basins forming what can be Species considered biogeographical islands Pool
  10. 10. The changing biogeography of fishes• There is a long history of introduction of non-indigenous fishes in freshwater ecosystems, the rate of which has accelerated greatly over time as methods of transportation have improved and trade barriers have relaxed• Historical motivation dates back to the Roman Empire and the extensive fish culturing of the common carp (Cyprinus carpio)• Today, fish introductions number in the thousands, occurring via a multitude of intentional and inadvertent vectors, and whose establishment is promoted by human activities
  11. 11. Circumventing natural barriers to fish movement Global Fauna • Inter-continental transport of Oceans, species for sport fishing, mountains aquaculture, ornamental trade, and live seafoodContinental Fauna • Ballast water transport Catchment divides Basin Fauna Waterfalls, cascades Local Species Pool
  12. 12. Ballast Water Ornamental TradeGlobal shipping trafficHalpern et al. 2008 June 5, 2005 - Woman charged with smuggling fish in skirt Customs officials hear ‘flipping’ noises, find 51 tropical species
  13. 13. Intentional Introductions of Freshwater Fishes J. D. Olden (unpublished)
  14. 14. Global distribution of rainbow trout, Oncorhynchus mykiss
  15. 15. Circumventing natural barriers to fish movement Global Fauna Oceans, mountainsContinental Fauna Catchment • Inter- and intra-basin transport divides of species for sport fishing, aquaculture Basin Fauna • Bait bucket and aquarium releases Waterfalls, cascades • Shipping canals Local • Overland transport via boats Species Pool
  16. 16. Intentional transport of sport fishes Photos Courtesy of the Catskill Archive
  17. 17. Fish invasions: Challenges andopportunities for ecological research• Through a variety of mechanisms, humans have increased the connectivity of freshwater systems that were historically isolated by biogeographic barriers to movement• As the number of introduced species continue to grow, the need to logically consider how this process influences the present-day biogeography of freshwater fish faunas becomes more and more critical• Invasive species also provide an unique opportunity to test various ecological, evolutionary, and biogeographical concepts and theories in freshwater ecology
  18. 18. Fish conservation biogeography in a rapidly changing world• Ecologists are now challenged to reconcile the historical biogeography of long-evolved native fishes with the emerging and rapidly expanding spread of invasive species• Advances will be achieved with a globalization of ecological thought• Janus-approach to fish conservation biogeography Roman God, Janus
  19. 19. Acknowledgements• Emili García-Berthou• Mark Kennard• Fabien Leprieur• Pablo Tedesco• Kirk WinemillerContact information:Julian OldenSchool of Aquatic and Fishery SciencesUniversity of Washingtonolden@u.washington.edu