Bioassessment of Freshwater Ecosystems: Using the Reference Condition Approach

ISBN-13: 9781402076701 / Angielski / Twarda / 2003 / 170 str.

Robert C. Bailey;Richard H. Norris;Trefor B. Reynoldson

Opis

Aquatic ecosystem assessment is a rapidly developing field, and one of the newer approaches to assessing the condition of rivers and lakes is the Reference Condition Approach. This is a significant advancement in biomonitoring because it solves the problem of trying to locate nearby control or reference sites when studying an ecosystem that may be degraded, a problem that bedevils traditional approaches. Rather than using upstream reference sites in a river system or next-bay-over reference sites in a lake, an array of ecologically similar, least-exposed to stress sites scattered throughout a catchment or region is used. Once the reference condition has been established, any site suspected of being impacted can be assessed by comparison to the reference sites, and its status determined. The Reference Condition database, once formed, can be used repeatedly.
The Reference Condition is established by standardized sampling of both the biota and its environment at a number of reference sites. A variety of environmental variables is measured in conjunction with sampling the biota (usually benthic invertebrates). In this book, we describe the basic methods involved in selecting and sampling appropriate reference sites, comparing test sites to appropriate reference sites using predictive modeling, and determining whether or not test sites are in the reference condition. This provides a rapid assessment method that can deal with everything from large-scale, national issues to local-scale problems with the same approach, and often parts of the same database.

Spis treści

Bioassessment Of Freshwater Ecosystems.- 1. Introduction.- 2. Key concepts.- 3. Development of the Reference Condition Approach.- 4. Points to remember.- To The Case Studies.- 1. Sediment assessment of the near shore environment of North American Great Lakes.- 2. Fraser River (British Columbia) biomonitoring program.- 3. Spring and Autumn Assessment of Streams in the Australian Capital Territory.- 4. Points to remember.- Defining The Reference Condition.- 1. Define the objectives of the study.- 2. Determine the spatial extent, time-scale and grain-size of the study.- 3. Determine the criteria for acceptable reference sites.- 4. Determine the appropriate number and locations of reference sites.- 5. Choose descriptors of the benthic invertebrate community and its environment.- 6. Design a data storage and management system.- 7. Ensure data quality.- 8. Case Studies.- 9. Points to remember.- Variation In The Reference Condition.- 1. Why characterizing reference site variation is important.- 2. How to describe variation among reference sites.- 3. Case Studie.- 4. Why it is important to model and explaine variation among reference sites.- 5. How to model variation among reference sites.- 6. Why residual variation among reference communities is important.- 7. Case studies.- 8. Points to remember.- Decision-Making.- 1. Why do we need decision rules on passing and failing test sites.- 2. How are decision rules arrived at.- 3. Sensitivity of assessments: how often do real test sites fail.- 4. Case Studies.- 5. Points to remember.- Beyond Pass And Fail.- 1. Severity of fail: Magnitude and nature of deviation from Reference Condition.- 2. Why did it fail.- 3. Scenario building: What will be the effect of rehabilitation or stress.- 4. Points to remember.- The Reference Condition Approach.- 1. Bioassessment of freshwater ecosystems using the Reference Condition Approach.- 2. Case Studies.- 3. Defining the Reference Condition.- 4. Describing and modeling variation in the Reference Condition.- 5. Decision-Making.- 6. Beyond Pass and Fail.- 7. Finish.- References.