Defining Macroinvertebrate Assemblage Types of Headwater Streams: Implications for Bioassessment and Conservation

Abstract

We used data from 235 boreal headwater streams in Finland to examine whether macroinvertebrate assemblages constitute clearly definable types, and how well biologically defined assemblage types can be predicted using environmental variables. Twoway indicator species analysis produced 10 assemblage types, which differed significantly from each other (multiresponse permutation procedure, MRPP). However, based on MRPP and nonmetric multidimensional scaling, there was wide variation among sites within each assemblage type, and high degrees of overlap among assemblage types. Such continuous variation was also evidenced by the low number of effective indicator taxa (indicator value method) for each assemblage type. Furthermore, discriminant function analysis based on environmental variables showed a moderate yet variable prediction success (59.6% of sites correctly predicted; range 0-96% per group). Canonical correspondence analysis indicated that variation in assemblage structure was primarily related to latitude and water chemistry, especially pH and water color. The absence of discrete macroinvertebrate assemblage types in boreal headwater streams may stem from a number of reasons: (1) macroinvertebrate taxa inhabiting boreal streams tend to exhibit individualistic, taxon-specific responses to environmental gradients, (2) they have wide environmental tolerances and geographic distributions, and (3) boreal streams are characterized by frequent, unpredictable disturbances. Our results suggest that local filters in headwater streams are relatively weak, resulting in poorly distinguishable assemblage types. By contrast, the major latitudinal gradients in macroinvertebrate assemblage structure suggest that regional-scale filters, e.g., temperature, exert strong control over taxon distributions in headwater streams. We suggest that a tiered approach combining regional stratification and subsequent prediction of assemblage structure could provide a suitable framework for the bioassessment and conservation of boreal headwater streams.

Large-scale macroinvertebrate assemblage patterns from least-disturbed wadeable stream sites across the 48 contiguous US states

“…Because perceptions about which environmental factors are most strongly related to assemblage composition depend in part on the spatial extent of observation (Marchant et al, 1999;Sandin and Johnson, 2004;Bonada et al, 2005;Johnson et al, 2007), we expected that we might find some consistencies and some differences between results of our study and those of other large-scale or national studies from elsewhere in the world. With ordinations based on invertebrates being identified to the finest practical level, we and others (Marchant et al, 1999;Turak et al, 1999;Heino et al, 2003;Lorenz et al, 2004;Sandin and Johnson, 2004) found a prominent relationship between invertebrate assemblage composition and geographic position (e.g. latitude and/or longitude).…”

“…However, understanding the major factors relating to assemblage composition at a broad scale can give context to our understanding of factors controlling assemblages at smaller scales of observation. Regional or national macroinvertebrate assemblage patterns in streams least disturbed by human activities have been examined in Europe Heino et al, 2003;Lorenz et al, 2004;Sandin and Johnson, 2004), Australia (Marchant et al, 1999;Smith et al, 1999;Turak et al, 1999), and North America (Waite et al, 2000). Examinations of assemblage patterns at even larger spatial scales are not often attempted because of the difficulty of collecting a large number of samples over a wide area, and collecting and analyzing samples and data in a consistent manner.…”

Spatial distribution of benthic macroinvertebrates in the Erhai basin of southwestern China

“…In this study, macroinvertebrate distributions were mainly . In numerous studies (e.g., Miserendino 2001;Heino et al 2003;Soldner et al 2004), altitude and water chemistry always related to the macroinvertebrate assemblages. Altitude directly determines some environmental factors such as temperature and illumination in a region.…”

Are Water Framework Directive stream types biologically relevant? The case of the Mondego river, Portugal

“…In addition, there were no signficant differences in taxa richness and total abundance among stream types. Finally, CA ordination plots showed no easily identifiable groups and a great overlap between predefined types might be indicative of a weak classification when all the assemblage is used (see Heino et al, 2003;Heino and Mykra, 2006). Verdonschot and Nijboer (2004) indicate that differences between stream types are only partly explained by qualitative differences in species lists but are also influenced by differences in abundances of individual species.…”

“…Since catchment geomorphology and climate-related variables are often strong predictors of macroinvertebrate assemblages (Richards et al, 1996;Hawkins et al, 2000;Verdonschot and Nijboer, 2004;Chaves et al, 2005), sites within the same WFD type that were based on these factors are expected to represent relatively distinct ecological units for invertebrate communities (Verdonschot, 2006a;Sa´nchez-Montoya et al, 2007). Alternatively, in bottomup approaches, aquatic biological data are used to group similar stream sites (e.g., Wright et al, 1984;Parsons and Norris, 1996;Marchant et al, 1997;Ehlert et al, 2002;Heino et al, 2003;Lorenz et al, 2004;Dodkins et al, 2005;Sa´nchez-Montoya et al, 2007). To accomplish this purpose biotic data should be collected in reference sites since anthropogenic stress reduces natural differences between communities (Verdonschot, 2006a).…”