Identification of predominant environmental factors structuring stream macroinvertebrate communities within a large agricultural catchment

Abstract

1. Patterns of macroinvertebrate community composition were examined in streams within a 40000-km^ catchment in central Michigan, U.S.A., to identify the major environmental gradients influencing community variation. Agriculture and associated clay and sandy soils predominated in much of the region. 2. Eighty macroinvertebrate taxa were collected from stream surveys conducted during May and August 1990. Community composition varied primarily by the proportions of Plecoptera and Ephemeroptera. Benthic communities from the heaviest agricultural zones were most different from those at other sites. 3. Chemical composition among the sites varied most in relation to nutrients (NH3, NO3, PO4). Other parameters were relatively similar. Physical characteristics of the sites were scored in six habitat categories: (i) substrate characteristics, (ii) instream cover, (iii) channel morphology, (iv) riparian zone and stream-bank conditions, (v) riffle/run quality, (vi) pool quality. Most physical habitat scores were lowest in the intense agriculture zones. 4. The relative importance of physical and chemical variables in explaining variation in macroinvertebrate communities was quantified using canonical correspondence analysis. Substrate characteristics were most important in both surveys. Significant correlations (P<0.05 and P<0.10) were observed between substrate quality and total numbers of Ephemeropteran, Plecopteran, and Trichopteran taxa. These relationships reflected correlations from sites in the clay soil-type region (P<0.01 and P<0.10) which contrasted with non-significant results from the less impacted, sandy soil-type region. 5. Effective stream restoration efforts in this region will require the alteration of local land-use activities that influence the physical habitat. Further development of empirical relationships between catchment activities and substrate and channel characteristics within natural geomorphic regions is essential for the evaluation of restoration projects.

The relative influence of geographic location and reach-scale habitat on benthic invertebrate assemblages in six ecoregions

“…Once sites were partitioned into Fine and Coarse, substrate was reduced to a less important variable for the coarse-grained group (CG, r = −0.28), but dropped out as a variable for the Fine model. Substrate has long been recognized as a major controlling factor for benthic invertebrates in that it commonly explains much of the invertebrate assemblage composition and distribution of populations (Rempel et al 2000;Richards et al 1993). The importance of substrate in controlling benthic invertebrates is related to organic matter retention (Culp et al 1983), biotic interactions of predation and competition (Lancaster et al 1990), and providing in-stream flow refugia from hydraulic stress (Lancaster and Hildrew 1993).…”

Diversity and structure of Ephemeroptera, Plecoptera and Trichoptera (Insecta) assemblages from riffles in mountain streams of Central Brazil

“…1980, RICHARDS et al 1993, ZAMORA-MUÑOZ et al 1993, ZAMORA-MUÑOZ & ALBA TERCEDOR 1996, BISPO et al 2006. Those characteristics vary in time and space; therefore, it is expected that those variation determine the spatial and temporal alteration of diversity and of structure of fauna in the aquatic communities.…”

Assessing the influence of source distance and hydroecoregion on the invertebrate assemblage similarity in central Italy streams

“…This is probably due to differences in the abundances of each single taxon rather than in the number of taxa (Supplementary material I). The importance of physico-chemical variables for determining macroinvertebrate assemblages was largely evaluated (Wright et al, 1984;Richards et al, 1993;Murphy and Davy-Bowker, 2005 upstream-downstream gradient (Schlosses, 1990). Great attention may be focus on the parameters used to define HER (Wasson et al, 2002).…”