The effects of macroinvertebrate taxonomic resolution in large landscape bioassessments: an example from the Mid‐Atlantic Highlands, U.S.A.

Abstract

1. During late spring 1993-1995, the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program (EMAP) sampled 490 wadeable streams in the mid-Atlantic Highlands (MAH) of the U.S. for a variety of physical, chemical and biological indicators of environmental condition. We used the resulting data set to evaluate the importance of differing levels of macroinvertebrate taxonomic resolution in bioassessments by comparing the ability of family versus genus to detect differences among sites classified by type and magnitude of human impact and by stream size. We divided the MAH into two physiographic regions: the Appalachian Plateau where mine drainage (MD) and acidic deposition are major stressors, and the Ridge and Valley where nutrient enrichment is a major stressor. Stream sites were classified into three or four impact classes based on water chemistry and habitat. We used stream order (first to third Strahler order) in each region as a measure of stream size. Ordination, 2 · 2 chi-square and biotic metrics were used to compare the ability of family and genus to detect differences among both stressor and size classes. 2. With one notable exception, there were only a small number of different genera per family (interquartile range ¼ 1-4). Family Chironomidae, however, contained 123 different genera. As a result, significant information loss occurred when this group was only classified to family. The family Chironomidae did not discriminate among the predefined classes but many chironomid genera did: by chi-square analysis, 10 and 28 chironomid genera were significant in discriminating MD and nutrient impacts, respectively. 3. Family and genus data were similar in their ability to distinguish among the coarse impacts (e.g. most severe versus least severe impact classes) for all cases. Though genus data in many cases distinguished the subtler differences (e.g. mixed/moderate impacts versus high or low impacts) better than family, differences in significance levels between family and genus analyses were relatively minor. However, genus data detected differences among stream orders in ordination analyses that were not revealed at the 474 This article is the material of the U.S. Government and can be reproduced by the public at will. family level. In the ordinations, both family and genus levels of analysis responded to similar suites of environmental variables. 4. Our results suggest that identification to the family level is sufficient for many bioassessment purposes. However, identifications to genus do provide more information in genera-rich families like Chironomidae. Genus or finer levels of identification are important for investigating natural history, stream ecology, biodiversity and indicator species. Decisions about the taxonomic level of identification need to be study specific and depend on available resources (cost) and study objectives.

Ecological Integrity of Streams Related to Human Cancer Mortality Rates

“…Second, analyses of macroinvertebrate genera and species are needed to understand possible mechanistic links to public health and to apply laboratorybased physiological research to field-based bioassessment survey results. For example, the SCI was calculated from family-level data, but macroinvertebrate genera have shown greater sensitivity to stressors in the Central Appalachians (Waite et al, 2004). Third, spatial analyses of human health and ecological integrity are needed across larger geographic extents to evaluate the generality of the results presented here.…”

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

“…While our study was able to maintain between 62% to 72% at the genus level and 23% to 36% at the family level, we had to aggregate chironomids to the family level. Waite et al (2004) reported that while familylevel taxonomy is sufficient for many bioassessment studies, the use of genus-level taxonomy is preferred when investigating finer level responses as in natural history and indicator species. They also reported that aggregating chironomids to the family level greatly reduced their ability to distinguish among many potential impacts (Waite et al 2004).…”

“…Waite et al (2004) reported that while familylevel taxonomy is sufficient for many bioassessment studies, the use of genus-level taxonomy is preferred when investigating finer level responses as in natural history and indicator species. They also reported that aggregating chironomids to the family level greatly reduced their ability to distinguish among many potential impacts (Waite et al 2004). Therefore, our inability to utilize genus level chironomid data likely influenced our NMS models, particularly in the fine-grain dominated ecoregions like the Valley and Plains.…”

Challenges using extrapolated family-level macroinvertebrate metrics in moderately disturbed tropical streams: a case-study from Belize

“…The efficacy with which family-level metrics can detect subtle environmental change is increasingly questioned by researchers in temperate streams (Hawkins et al, 2000, Lenat & Resh, 2001, Waite et al, 2004, Heino, 2014.…”

“…Others have illustrated the high discriminatory power that generic-and species-level information can provide (Dudgeon, 2012, Monk et al, 2012, even where the magnitude of disturbance is small (Hawkins et al, 2000, Benstead et al, 2003, Waite et al, 2004, Buendia et al, 2013. Some traits are considered relatively stable among genera of many families (Dolédec et al, 2000).…”