Using macroinvertebrate biological traits for assessing biotic integrity of neotropical streams

Several recent studies have demonstrated that a functional approach (i.e. analysis of traits indicating species ecological functions) can be successfully used for river biomonitoring. To date this approach has only been applied in temperate rivers, even though it could notably contribute toward the development of an environmental assessment system in developing countries in other climatic zones. Using a multivariate approach (Fuzzy Correspondence Analysis--FCA), we analysed functional invertebrate community characteristics (described by 40 categories of seven biological traits mostly at the family level) at 66 stream sites from neotropical Bolivia with different level of anthropogenic disturbance. We were able to separate the sites on the first FCA axis (F1) (ANOVA test) following the predefined environmental quality classes based on the observed impact. Moreover, the F1 axis scores were significantly related to scores obtained using an independent macroinvertebrate multi-metric index previously developed to assess streams biotic condition in the same biogeographical region. The F1 axis, which thus represents a gradient of anthropogenic impacts, was significantly correlated to 30 of the 40 studied trait categories. Our results (i) clearly confirm the possible use of functional traits for water quality assessment in neotropical streams, and (ii) provides support to the River Habitat Templet hypothesis since habitat disturbances produced predictable functional changes in macroinvertebrate assemblages. Finally, this study supports the potential worldwide applicability of the species-trait approach as a biomonitoring tool for stream integrity assessment. Copyright © 2008 John Wiley & Sons, Ltd.