quantitative estimates of the ecological integrity of freshwater ecosystems.
We discuss important developments made in the latter half of the twentieth century
which are still relevant and useful for bioassessment, as well as more recent
developments that have improved the effectiveness of bioassessment strategies.
Throughout the chapter, we focus on analytical approaches for improving the
effectiveness of bioassessment indices for detecting anthropogenic impairment. In
the concluding section of the chapter, we widen our perspective and include
excerpts from discussions with three expert practitioners on topics that are more
broadly applicable to the assessment of the ecological integrity of aquatic systems.
The major challenge for all bioassessment programs is to separate the effects of
anthropogenic impairment on biota from the effects of natural environmental
variability unrelated to impairment. Analytical developments, such as advanced
predictive modeling techniques, coupled with emerging technologies and the
development of large-scale bioassessment programs will continue to increase our
ability to meet this challenge and to improve our understanding of how aquatic
assemblages are affected by anthropogenic impairment.
Keywords Aquatic ecosystems • Bioassessment • Biomonitoring • Biotic assemblages • Predictive modeling
1 Introduction
The US Environmental Protection Agency (USEPA) defines biological assessment
as the “. . .evaluation of the condition of a waterbody using biological surveys and
other direct measurements of the resident biota in surface waters” [1]. Investigations
that fall under this broad definition may be focused on any level of biological
organization, from studies of subcellular effects of toxic compounds [2] to
ecosystem-scale assessments using multiple taxonomic assemblages [3]. The
terms biological assessment, bioassessment, biological monitoring, and
biomonitoring are often used interchangeably. For clarity, we restrict our discussion
to the term bioassessment.
The value of aquatic organisms as pollution indicators has been recognized by
scientists for over 100 years. The Saprobiensystem of Kolkwitz and Marsson [4],
most probably the first bioassessment index, was a system for quantitatively rating
the tolerance of aquatic organisms to sewage pollution, much akin to modern
pollution tolerance values. This concept has been adapted and modified many
times, and both the concept and use of the word “saprobity” persist in contemporary
literature [5, 6]. The practice of bioassessment invokes the concept of biological
integrity, defined as “the capability of supporting and maintaining a balanced,
integrated, adaptive community of organisms having a species composition, diversity, and functional organization comparable to that of natural habitat of the region”
[7, 8]. Practitioners conducting bioassessments assume that biotic integrity reflects
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A.L. Garey and L.A. Smock
We discuss important developments made in the latter half of the twentieth century
which are still relevant and useful for bioassessment, as well as more recent
developments that have improved the effectiveness of bioassessment strategies.
Throughout the chapter, we focus on analytical approaches for improving the
effectiveness of bioassessment indices for detecting anthropogenic impairment. In
the concluding section of the chapter, we widen our perspective and include
excerpts from discussions with three expert practitioners on topics that are more
broadly applicable to the assessment of the ecological integrity of aquatic systems.
The major challenge for all bioassessment programs is to separate the effects of
anthropogenic impairment on biota from the effects of natural environmental
variability unrelated to impairment. Analytical developments, such as advanced
predictive modeling techniques, coupled with emerging technologies and the
development of large-scale bioassessment programs will continue to increase our
ability to meet this challenge and to improve our understanding of how aquatic
assemblages are affected by anthropogenic impairment.
Keywords Aquatic ecosystems • Bioassessment • Biomonitoring • Biotic assemblages • Predictive modeling
1 Introduction
The US Environmental Protection Agency (USEPA) defines biological assessment
as the “. . .evaluation of the condition of a waterbody using biological surveys and
other direct measurements of the resident biota in surface waters” [1]. Investigations
that fall under this broad definition may be focused on any level of biological
organization, from studies of subcellular effects of toxic compounds [2] to
ecosystem-scale assessments using multiple taxonomic assemblages [3]. The
terms biological assessment, bioassessment, biological monitoring, and
biomonitoring are often used interchangeably. For clarity, we restrict our discussion
to the term bioassessment.
The value of aquatic organisms as pollution indicators has been recognized by
scientists for over 100 years. The Saprobiensystem of Kolkwitz and Marsson [4],
most probably the first bioassessment index, was a system for quantitatively rating
the tolerance of aquatic organisms to sewage pollution, much akin to modern
pollution tolerance values. This concept has been adapted and modified many
times, and both the concept and use of the word “saprobity” persist in contemporary
literature [5, 6]. The practice of bioassessment invokes the concept of biological
integrity, defined as “the capability of supporting and maintaining a balanced,
integrated, adaptive community of organisms having a species composition, diversity, and functional organization comparable to that of natural habitat of the region”
[7, 8]. Practitioners conducting bioassessments assume that biotic integrity reflects
234
A.L. Garey and L.A. Smock