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Upstream-to-Downstream Changes in Nutrient Export Risk

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Abstract:One of the early operating principles of landscape ecology was the importance of studying the
movement of energy, nutrients, and biota in the horizontal or x,y plane (Risser et al. 1984). The new focus on horizontal movement was in part based on the recognition that many ecological studies had abstracted the horizontal domain (Reynolds and Wu 1999), Ecological risk assessment (O'Neill et al. 1982, Bartell et al. 1992, Suter 1993) emerged at about the same time as the field of landscape ecology, and focused on estimating the likelihood of an event
(e.g., local extinction of a taxa). Ecological risk assessment developed as an extension of ecotoxicology (Truhaut 1977). Application of risk assessment to the field of ecotoxicology was based on the observations: (1) that manufactured chemicals were being produced too rapidly for study of biotic effects to keep pace (Maugh 1978), and (2) that laboratory testing to determine lethal concentrations did not necessarily accurately re-create an ecological microsm that could be extended to an ecosystem level (O'Neill et al. 1982, Bartell et al. 1992). Some books on ecological risk assessment (Bartell et al. 1992, Suter 1993) close with discussions on how risk assessment might be applied to disciplines other than ecotoxicology, including landscape-scale studies. Richards and Johnson (1998) also discuss how ecological risk assessments fit within the context of landscape ecology. The few existing ecological risk assessments at a landscape- scale have focused on identifying spatial variation in risk across the x,y plane (Graham et al. 1991, Wickham and Wade in press, Wickham et al. in press). A horizontal, process-oriented perspective of landscape-level ecological studies (Reynolds and Wu 1999) suggests that propagation of risk in the xy plane should also be studied. Johnson (2000) investigated spatial propagation of toxic chemicals using organismal movement across the landscape - a landscape level ecotoxicology. Spatial propagation of nutrient export across watersheds provides a landscape-level perspective of nutrient transport.

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Citation:Wickham, J. D., T. G. Wade, K. H. Riitters, R. V. O'neill, J. H. Smith, E. R. Smith, K. B. Jones, and A. C. Neale. Upstream-to-Downstream Changes in Nutrient Export Risk. LANDSCAPE ECOLOGY 18(2):193-206, (2003).
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Contact: Chris Siebert - (702) 798-2234 or siebert.christopher@epa.gov
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Division: Environmental Sciences Division
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Branch: Landscape Characterization Branch (RTP)
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Product Type: Journal
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Published: 06/24/2003
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Downloads:
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Bullet Item Journal Article..PDF
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Bullet Item Http:/~/~ Link.springer.com/Article/10.1023/A%3a1024490121893   Exit EPA's Web Site
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Related Entries:
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Bullet Item Landscape Characterization and Change Detection Methods Development Research (2005-2007)
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