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Assessments 2 : What the biota can tell us about watershed condition K.E. Limburg lecture notes

Assessments 2 : What the biota can tell us about watershed condition K.E. Limburg lecture notes 26 March, 2002. Outline Intro: a brief glimpse at a defining moment for KL What we mean by “watershed health” Biotic assessments – common methods.

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Assessments 2 : What the biota can tell us about watershed condition K.E. Limburg lecture notes

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  1. Assessments 2: What the biota can tell us about watershed condition K.E. Limburg lecture notes 26 March, 2002

  2. Outline • Intro: a brief glimpse at a defining moment for KL • What we mean by “watershed health” • Biotic assessments – common methods

  3. Biotic assessments – an introduction through a study by KL and colleagues in the Hudson River watershed

  4. Research project: “Larval fish use of tributaries of the Hudson” – R.E. Schmidt and K.E. Limburg Goal: to quantify “larval fish flux” from tributaries to the mainstem – connecting the system pieces

  5. Initial hypotheses: • Spawning would proceed from south to north (temperature effect) • More production in smaller streams • Anthropogenic effects might be important

  6. Studied 16 tribs, in 4 “reaches” of the estuary: 1st to 9th order • sampled weekly for 15 weeks in spring • 4 teams sampled during same 48 hr period – synoptic survey • collected fish larvae, measured flow, DO, pH

  7. Some had obvious problems! Some streams were sublime

  8. Some streams were just mysterious at the time!

  9. Methods Dusk sampling…

  10. “proto-GIS” Method of quantifying land use

  11. Results

  12. Strong spatial patterns Ln(1+(#fish/m3))

  13. Main points: Tribs warmed up more or less simultaneously – we did not see a south-to-north trend in fish production Size of stream did not appear to matter in this study Land use type, in particular, land in urban and suburban uses, did!! Verified by other studies in other places

  14. Watershed Health • How does land use change affect the ecological structure and function of a watershed? • How can environmental change be linked to land use and economic change? • What is/should be the role of watershed health and monitoring in designing policy? • How does tributary health affect the larger ecosystem?

  15. Ecosystem (and hence, watershed) health, qu’est-ce que c’est? - a concept that’s been around a long time, currently enjoying a comeback • maintenance of “biotic integrity” • resistance and/or resilience of systems in the face of disturbance • absence of factors that degrade ecological population, community, and ecosystem structure and function

  16. Waterways and water bodies are often good sites for assessing “watershed health” -- why?

  17. Ecosystem indicators of anthropogenic disturbance should ideally be sensitive to these factors, and not confounded by natural ones (or at least possible to tease out the differences) Metric B Metric A Low Human influence High

  18. Federal, state, local agencies have really espoused this concept So have many non-profit organizations Possible to enlist the help of many volunteers (e.g., FL-LOWPA, Hudson R. Basin Watch) US EPA

  19. EPA Bioindicators homepage: http://www.epa.gov/bioindicators/index.html

  20. US EPA

  21. US EPA

  22. US EPA

  23. US EPA

  24. Assessing watershed health with biotic indicators: The idea: organisms and ecosystems integrate and reflect the insults (or lack thereof) resulting from watershed-level processes Some techniques have proven robust after 25+ years of testing; others in development

  25. Indicators of ecosystem health can (should?) evaluate changes at levels of • Population • Community/habitat • Whole-system Metrics may not all be additive, although many schemes designed that way

  26. Ideal indicator species characteristics (Resh and Rosenberg, 1993) • Taxonomic soundness and easily recognized • Cosmopolitan distribution • Numerical abundance • Low genetic and ecological variability • Large body size • Limited mobility and relatively long-life history • Ecological characteristics are well known • Suitable for use in laboratory studies

  27. Example: Index of Biotic Integrity (IBI) • Uses fish community characteristics to assess aquatic health: includes for example • Species richness & abundance • Total biomass (and distribution) • Ratio of native spp to introduced • Functional role ID (generalists vs specialists, detritivores, piscivores, etc) • Condition & health indices

  28. IBI’s originally worked out for Ohio streams (James Karr and colleagues) • in general, these are region-specific • therefore, IBI’s must be calibrated to a given region • for northern Mid-Atlantic drainages, a calibration study for a regional IBI will soon be published (Daniels et al., Transactions of the American Fisheries Society)

  29. Other taxonomic can also be used as indicators of watershed condition – most, but not all, work is done in streams: • benthic macroinvertebrates • periphyton • macrophytes (aquatic and wetland) • birds (some work in PA and Southeast)

  30. NY State biotic assessment website: http://www.dec.state.ny.us/website/dow/stream/index.htm This site is specifically for rapid bio-assessments using stream macroinvertebrates – contains a pictorial key and verbal descriptions

  31. Pro’s and con’s of indicators

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