A heuristic framework for understanding and predicting the distribution and categorical abundance of species in stream communities is presented. The framework requires that species be described in terms of their functional relationships to habitat selective forces or their surrogates, which constitute "filters" occurring at hierarchical landscape scales (ranging from microhabitats to watersheds or basins). Large-scale filters are viewed as causative or mechanistic agents that constrain expression of local selective forces or biotic potential at lower scales. To join a local community, species in a regional pool must possess appropriate functional attributes (species traits) to "pass" through the nested filters. Biotic interactions are also a potential filter on local community composition, and they are invoked at the lower hierarchical levels, after species have passed through the physicochemical habitat filters. Potential landscape filters and their associated selective properties are identified, as are ...

Landscape filters and species traits: Towards mechanistic understanding and prediction in stream ecology

Water of sufficient quality and quantity is critical to all life. Increasing human population and growth of technology require human society to devote more and more attention to protection of adequate supplies of water. Although perception of biological degradation stimulated current state and federal legislation on the quality of water resources, that biological focus was lost in the search for easily measured physical and chemical surrogates. The "fishable and swimmable" goal of the Water Pollution Control Act of 1972 (PL 92-500) and its charge to "restore and maintain" biotic integrity illustrate that law's biological underpinning. Further, the need for operational definitions of terms like "biological integrity" and "unreasonable degradation" and for ecologically sound tools to measure divergence from societal goals have increased interest in biological monitoring. Assessment of water resource quality by sampling biological communities in the field (ambient biological monitoring) is a promising approach that requires expanded use of ecological expertise. One such approach, the Index of Biotic Integrity (IBI), provides a broadly based, multiparameter tool for the assessment of biotic integrity in running waters. IBI based on fish community attributes has now been applied widely in North America. The success of IBI has stimulated the development of similar approaches using other aquatic taxa. Expanded use of ecological expertise in ambient biological monitoring is essential to the protection of water resources. Ecologists have the expertise to contribute significantly to those programs.

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Biological Integrity: A Long-Neglected Aspect of Water Resource Management

M ore than 40 years ago, conservationist Aldo Leopold articulated the need for a "land ethic," or self-imposed limitation on the degree to which a person will modify the landscape, to protect overall ecosystem quality (Leopold 1949). Since Leopold made that plea, land use has continued to be a primary factor causing the decline of fishery resources in stream ecosystems (Karr et al. 1985, Salo and Cundy 1987). The pervasiveness of degradation of these resources indicates that most land-use decisions have been made with little understanding or regard for their effect on adjacent and more distant components of the landscape. Landscape ecology (Forman and Godron 1986) offers new opportunities for improving understanding of landscape dynamics and strengthening decisions regarding the influence of land-use disturbances on fishery resources. Landscape ecology focuses on three interrelated characteristics of the environment: structural relationships among landscape elements; functional interactions among these elements, including the flow of water, organic matter, nutrients, and species; and natural and anthropogenic changes in structural and functional relationships of landscape elements over time. In this article, I briefly review the basic life cycle of stream fish and the

https://www.jstor.org/stable/pdfplus/1311765.pdf

Stream Fish Ecology: A Landscape PerspectiveLand use, which influences the terrestrial-aquatic interface, can affect fish populations and their community dynamics

The biological integrity of stream ecosystems depends critically on human activities that affect land use/cover along stream margins and possibly throughout the catchment. We evaluated stream condition using an Index of Biotic Integrity (IBI) and a habitat index (HI), and compared these measures to landscape and riparian conditions assessed at different spatial scales in a largely agricultural Midwestern watershed. Our goal was to determine whether land use/cover was an effective predictor of stream integrity, and if so, at what spatial scale. Twenty-three sites in first-through third-order headwater streams were surveyed by electrofishing and site IBIs were calculated based on ten metrics of the fish collection. Habitat features were characterized through field observation, and site HIs calculated from nine instream and bank metrics. Field surveys, aerial photograph interpretation, and geographic information system (GIS) analyses provided assessments of forested land and other vegetation covers at the local, reach, and regional (catchment) scales.

Landscape influences on stream biotic integrity assessed at multiple spatial scales

Arthropods, the most diverse component of terrestrial ecosystems, occupy a tremendous variety of functional niches and microhabitats across a wide array of spatial and temporal scales. We propose that conservation biologists should take advantage of terrestrial arthropod diversity as a rich data source for conservation planning and management. For reserve selection and design, documentation of the microgeography of selected arthropod taxa can delineate distinct biogeographic zones, areas of endemism, community types, and centers of evolutionary radiation to improve the spatial resolution of conservation planning. For management of natural areas, monitoring of terrestrial arthropod indicators can provide early warnings of ecological changes, and can be used to assay the effects of further fragmentation on natural areas that no longer support vertebrate indicator species. Many arthropod indicators respond to environmental changes more rapidly than do vertebrate indicators, which may exhibit population responses that do not become evident until too late for proactive management. Not all arthropod taxa are equally effective as indicators for conservation planning, and the qualities of indicators can differ for purposes of inventory versus monitoring. Assemblages of arthropod taxa used as biogeographic probes in inventories should exhibit relatively high species diversity, high endemism, and encompass the geographic range of interest. For monitoring purposes, indicator assemblages should exhibit varying sensitivity to environmental perturbations and a diversity of life-history and ecological preferences.



Resumen: Los artropodos, el componente mas diverso de los ecosistemas terrestres, ocupa una tremenda variedad de nichos funcionales y microhabitats a lo largo de una amplio espectro de escalas espaciales y temporales. Nosotros proponemos que los biologos de conservacion deberian aprovechar la diversidad de los atropodos terrestres como una rica fuente para el planeamiento y manejo conservacionista. La documentacion de la microgeografia de ciertos taxones de artropodos puede delinear zonas biogeograficas precisas, areas de endemismo, tipos de comunidades, y centros de radiacion evolutiva para mejorar la resolucion espacial en el planeamiento conservacionista destinado a la seleccion y diseno de reservas. En cuanto al manejo de areas naturales, el monitoreo de artropodos terrestres puede proveer de avisos tempranos sobre cambios ecologicos y puede ser usado para investigar los efectos de la fragmentacion subsecuente de areas naturales que ya no mantienen especies de vertebrados indicadoras. Muchos artropodos indicadores responden a los cambios hambientales mas rapidamente que vertebrados indicadores, los cuales pueden exhibir respuestas poblacionales que solo se hacen evidentes cuando ya es muy tarde para el manejo proteccionista. No todos los taxones de artropodos son igualmente efectivos como indicadores para el planeamiento conservacionista, y las calidades de los indicadores pueden variar dependiendo si su uso es con fines de inventario o de monitoreo. Las asociaciones de artropodos usados como sondas en inventarios deberian exhibir diversidades especificas relativamente altas, alto endemismo y deberian abarcar el rango geografico de interes. Si son usados con propositos de monitoreo, las asociaciones de indicadores deberian exhibir diferentes sensibilidades a las perturbaciones ambientales, y diversidad en cuanto a historias de vida y preferencias ecologicas.

https://www.jstor.org/stable/pdfplus/2386811.pdf

Terrestrial Arthropod Assemblages: Their Use in Conservation Planning

The effect of siltation on stream fish in northeast Missouri was evaluated using community structural measurements and a functional approach that emphasized feeding and reproductive guilds. As the percentage of fine substrate increased, the distinction among riffle, run, and pool communities decreased, primarily because the number of individuals of typical riffle species decreased. Within the riffle communities the abundance of fish of two feeding guilds — benthic insectivores and herbivores — was reduced as the percent of fine substrate increased. The abundance of fish in other feeding guilds was not affected. The only reproductive guild to be similarly affected was the simple and lithophilous, whose members require a clean gravel substrate for spawning. Species within each guild affected by siltation had significantly similar trends in abundance. The guild analysis indicated that species with similar ecological requirements had a common response to habitat degradation by siltation.

Effect of siltation on stream fish communities

Although the utility of using either fish or benthic invertebrates as biomonitors of stream quality has been clearly shown, there is little comparative information on the usefulness of the groups in any particular situation. We compared fish to invertebrate assemblages in their ability to reflect habitat quality of sediment-impacted streams in agricultural regions of northeast Missouri, USA. Habitat quality was measured by a combination of substrate composition, riparian type, buffer strip width, and land use. Invertebrates were more sensitive to habitat differences when structural measurements, species diversity and ordination, were used. Incorporating ecological measurements, by using the Index of Biological Integrity, increased the information obtained from the fish assemblage. The differential response of the two groups was attributed to the more direct impact of sediments on invertebrate life requisites; the impact of sedimentation on fish is considered more indirect and complex, affecting feeding and reproductive mechanisms.

Biomonitors of stream quality in agricultural areas: Fish versus invertebrates

Although the utility of using either fish or benthic streams in agricul- tural regions of northeast Missouri, USA. Habitat quality was measured by a combination of substrate composition, ri- parian type, buffer strip width, and land use. Invertebrates were more sensitive to habitat differences when structural measurements, species diversity and ordination, were used. Incorporating ecological measurements, by using the Index of Biological Integrity, increased the information obtained from the fish assemblage. The differential response of the two groups was attributed to the more direct impact of sediments on invertebrate life requisites; the impact of sedimentation on fish is considered more indirect and complex, affecting feeding and reproductive mechanisms. The evaluation of water quality by an examination of resident aquatic life, an approach long espoused by aquatic biologists, was legislated by the US Clean Water Act (PL 95-217) of 1977. Biological communi- ties, or assemblges of similar organisms, have been generally recognized as useful in assessing water quality because they are sensitive to low-level distur- bances and function as continuous monitors (Chandler 1970). Although both fish and benthic invertebrate communities have been used in such assessments, there has been little agreement on which group is the more efficient. Invertebrate communities have often been used to assess stream perturbation (Chutter 1969, Cummins and Lauff 1969, Hellawell 1977), and are considered good indicators because they are relatively sedentary and enable the detection of localized disturbances. Their relatively long life histories allow for integration of pollution effects; qualitative field sampling is easy; and since the communities are heterogeneous and sev- ern phyla are usually represented, the chances are high that at least some groups (and therefore the com- munity as a whole) will respond to environmental ira-

http://rd.springer.com/content/pdf/10.1007%2FBF01867267.pdf

Hilary E. Berkman

Papers

Effect of siltation on stream fish communities

Biomonitors of stream quality in agricultural areas: Fish versus invertebrates

Biomonitors of Stream Quality in Fish versus Invertebrates Agricultural Areas