0–1 scale. The method can be applied to both categorical and continuous scales and
preserves the best professional judgment of developers regarding the interpretation
of score or measurement values.
Q: What aspects of the relationships of anthropogenic activities and ecological
integrity are most misunderstood by nonscientists?
A: The watershed (or catchment) concept is of great importance, though often
not understood by the layperson. Following from the simple concept that water
flows downhill, water bodies integrate the effects of human activities everywhere
within their watersheds. Responsible management of aquatic ecosystems must
consider not only in-stream and local effects but also effects at much larger spatial
scales. The range of relevant spatial scales that should be considered increases with
the size of the water body, with the largest river systems integrating the effects of
anthropogenic activities over thousands of square kilometers.
Q: In considering streams in different natural settings and at different positions
along the general gradient of impairment, which are the most important candidates
for preservation or restoration?
A: How best to prioritize conservation and restoration efforts for aquatic ecosystems is currently a popular and important topic in the EU. A strategy that
considers the conservation of existing ecological integrity and the restoration of
impaired systems simultaneously is best. When biological assemblage objectives
are given high priority, the most effective areas for restoration are those in close
proximity to high-quality conservation areas because the conservation areas provide sources for recolonization. For example, Tonkin et al. [148] evaluated
the likelihood of recolonization by invertebrates at 21 river restoration sites in
Germany. They determined that the density of occurrence of a taxon at surrounding
sites (proportion of sites with the taxon present) and the distance to the nearest
potential source site were important factors for predicting recolonization.
Expert 3 Gregory J. Pond, M.S.—Aquatic Biologist, USA Environmental Protection Agency, Region III, Wheeling, WV, USA
Q: Given the myriad protocols currently employed to conduct assemblage-level
assessments, what considerations should be made by investigators and managers to
select the most accurate, precise, and cost-effective strategies?
A: Protocols should be flexible, thoroughly documented in standard operating
procedures, and based on the varying assessment goals, characteristics of the
system being studied and available funding. For example, species-level
macroinvertebrate data may in some cases produce the most effective assessment
results. In other situations, temporal variation among samples may produce confusion at high levels of taxonomic resolution, for example, if errors in identification
increase at times of the year when early instars predominate in the samples. In such
cases, coarser taxonomic resolution at the genus or family level may be necessary to
avoid inconsistency among samples.
If assessment on a large spatial scale is a priority, investigators may use less
time-intensive methods to assess a greater number of sites within the time and
monetary constraints of the project. In an attempt to provide a spatially
256
A.L. Garey and L.A. Smock
preserves the best professional judgment of developers regarding the interpretation
of score or measurement values.
Q: What aspects of the relationships of anthropogenic activities and ecological
integrity are most misunderstood by nonscientists?
A: The watershed (or catchment) concept is of great importance, though often
not understood by the layperson. Following from the simple concept that water
flows downhill, water bodies integrate the effects of human activities everywhere
within their watersheds. Responsible management of aquatic ecosystems must
consider not only in-stream and local effects but also effects at much larger spatial
scales. The range of relevant spatial scales that should be considered increases with
the size of the water body, with the largest river systems integrating the effects of
anthropogenic activities over thousands of square kilometers.
Q: In considering streams in different natural settings and at different positions
along the general gradient of impairment, which are the most important candidates
for preservation or restoration?
A: How best to prioritize conservation and restoration efforts for aquatic ecosystems is currently a popular and important topic in the EU. A strategy that
considers the conservation of existing ecological integrity and the restoration of
impaired systems simultaneously is best. When biological assemblage objectives
are given high priority, the most effective areas for restoration are those in close
proximity to high-quality conservation areas because the conservation areas provide sources for recolonization. For example, Tonkin et al. [148] evaluated
the likelihood of recolonization by invertebrates at 21 river restoration sites in
Germany. They determined that the density of occurrence of a taxon at surrounding
sites (proportion of sites with the taxon present) and the distance to the nearest
potential source site were important factors for predicting recolonization.
Expert 3 Gregory J. Pond, M.S.—Aquatic Biologist, USA Environmental Protection Agency, Region III, Wheeling, WV, USA
Q: Given the myriad protocols currently employed to conduct assemblage-level
assessments, what considerations should be made by investigators and managers to
select the most accurate, precise, and cost-effective strategies?
A: Protocols should be flexible, thoroughly documented in standard operating
procedures, and based on the varying assessment goals, characteristics of the
system being studied and available funding. For example, species-level
macroinvertebrate data may in some cases produce the most effective assessment
results. In other situations, temporal variation among samples may produce confusion at high levels of taxonomic resolution, for example, if errors in identification
increase at times of the year when early instars predominate in the samples. In such
cases, coarser taxonomic resolution at the genus or family level may be necessary to
avoid inconsistency among samples.
If assessment on a large spatial scale is a priority, investigators may use less
time-intensive methods to assess a greater number of sites within the time and
monetary constraints of the project. In an attempt to provide a spatially
256
A.L. Garey and L.A. Smock