Responses of freshwater biota to human disturbances : contribution of J-NABS to developments in ecological integrity assessments
Résumé
Effective ecosystem management in the face of human alterations depends on our ability to quantify ecologically significant changes and to discriminate among impact levels and types. We reviewed the literature on biological responses of freshwater biota to human disturbances over the last century. Many of the main methods for assessing ecological integrity originated in Europe [e.g., Saprobien Index, Trent Biotic Index, Biological Monitoring Working Party, River InVertebrate Prediction And Classification System, multiple traits] or in North America [e.g., Index of Biotic Integrity, leaf-litter breakdown, functional feeding groups]. We used bibliometric data to detail the contribution of J-NABS to developments in assessment of ecological integrity. A total of 225 bioassessment articles were published in J-NABS from 1986 to 2007. This total was ½ of the number of bioassessment articles published over the same period in Freshwater Biology (FWB; another leading freshwater journal used for comparison), but the proportion of bioassessment articles in the 2 journals was similar (20%). The proportion of bioassessment articles in J-NABS has increased over the last 25 y. This trend indicates the growing interest in the topic and the delay (30 y since the Clean Water Act) of scientific action in response to water legislation. Taxonomic composition and multivariate techniques, multimetric indices, lotic systems, macroinvertebrates, land use, and overall human impacts were major themes in J-NABS bioassessment articles. Progress in bioassessment is needed in 3 main areas. First, bioassessments done at large spatial scales are needed to meet requirements of new environmental policies. Second, bioassessment should shift from consideration of taxon losses to losses of ecological functions. Third, statistical techniques are needed for predictive assessment of deviation in ecological integrity between expected (natural) and observed (natural or impacted) conditions. Assessment of functional integrity based on multiple traits is a promising area because biological traits represent universal biological characteristics that are connected to ecosystem functions. However, the relationships between ecophysiological traits of individuals and ecosystem-scale responses must be properly defined for specific types of human impairment, and utility of the approach for routine bioassessments applied by managers must be tested.