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FW Biodiversity in Peril

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FW Biodiversity in Peril

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  1. ECL 6080: August 27, 2009 - C. M. PringleDeclining Freshwater Biodiversity: Canaries in the Coal Mine1. Genetic, species and ecosystem-level declines and effects on products and eco- system services2. Major threats to freshwater biodiversity a) physical b) chemical c) biological

  2. FW Biodiversity in Peril • There are ~100,000 FW species in 14 phyla – but no comprehensive analysis of their status exists • 30% of ~10,500 fish species threatened mostly by habitat destruction • In North America, the extinction rate of FW organisms is 5X that of terrestrial fauna • An extinction rate of 4% per decade is expected for the future – and likely greater in tropical regions • Loss rates for system-level processes not known

  3. Landscape Communities & ecosystems Populations & species Genetic HIERARCHICAL LEVELS of biodiversity Ward et al. 1999

  4. Genetic-level • Destruction and loss of genetically distinct populations e.g., salmonids • Isolation of populations • Hatchery-reared fish

  5. Species-level • Loss of native species (accelerating rates of loss) -crayfish (51%) -mussels (69%) -fishes (37%) ---------------------- -mammals (13%) -birds (11%) • Extirpation of native species over much of their original range • Increasing numbers of exotic species

  6. Aquatic species at risk > 15% 10-15% 5-9% < 5% Includes mussels, crayfish, fishes, amphibians, reptiles, mammals and birds Modified from TNC (1997)

  7. Ecosystem-level Measuring the losses: -the US has lost over half of the wetlands that existed at the time of the American Revolution -Iowa retains only 1% of its natural marshes/prairie potholes; North Dakota-40%; Minnesota 47%; South Dakota 65% -Less than a quarter of bottomland hardwood forests remain in the midwest and the southern US -Much riparian habitat in arid regions of the US has been destroyed (<5% remains of original habitat in Arizona -Of 3.2 million miles of streams in the lower 48 states, only 2% of rivers are free-flowing and relatively undeveloped. Only 42 free-flowing rivers exist of over 125 or more miles in length. The other 98% of US streams have been developed

  8. Products/Ecosystem Services • Products -harvests of fishes and mussels • Water purification -oysters -wetlands -riparian buffer zones • Buffering the impact of floods

  9. Threats to freshwater ecosystems • Physical -dams -water abstraction (irrigation, groundwater pumping) -land-use change • Chemical -nutrients, toxics, persistant organic chemicals (PCBs), endocrine disruptors, pharmaceuticals • Biological -invasive species (competition, hybridization) Synergistic interactions between above

  10. PHYSICAL THREATS • Regulation (dams) • Water diversion • Groundwater exploitation Source: USACE (J. Jordan photo)

  11. DAMS

  12. Water diversions and abstraction

  13. Irrigation

  14. Soil salinization

  15. The shrinking Aral Sea1964 (left) and 1997 (right) • N • N

  16. Interbasin transfers threaten endemic taxa by promoting faunal exchange (diffusion of diverse communities that were previously isolated) and hybridization Insert water diversion map

  17. CHEMICAL THREATS • Point Source and • Non-point Source • Nutrient and • Toxic Loading • Emerging threats: • Endocrine Disruptors • Pharmaceuticals • Coastal Dead Zones

  18. Pesticides Source: USACE

  19. Pesticide runoff potential Watershed Qualification Low potential for runoff Moderate potential for runoff High potential for runoff Insufficient data Source: USEPA (1998)

  20. Global scale hydrologic connectivity and the transport of PCBs: Effects on arctic food webs

  21. News Item: Estrogen -imitating chemicals in the environment suspected of wide-ranging biological anomalies, including hermaphrodism in animals and lower sperm count in human beings… We in the business community prefer a more cautious “wait- and-see” approach over senseless media scare-mongering... Source: G. Olson

  22. Land-use and related chemical and physical threats to freshwater biodiversity

  23. Concentrated Animal Operations Source: NRCS

  24. URBANIZATION

  25. Photos: R. Bjorkland

  26. Impervious surfaces • Increase volume • Increase speed • Increase pollutants • Decrease infiltration Photo: R. Bjorkland

  27. BIOLOGICAL THREATS: EXOTIC SPECIES

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