Rare species in multivariate analysis for bioassessment: some considerations

Abstract

BRIDGES is a recurring feature of J-NABS intended to provide a forum for the interchange of ideas and information between basic and applied researchers in benthic science. Articles in this series will focus on topical research areas and linkages between basic and applied aspects of research, monitoring policy, and education. Readers with ideas for topics should contact Associate Editors, Nick Aumen and Marty Gurtz.Multivariate analyses are used commonly in bioassessment studies examining the degree of human impact on aquatic ecosystems. However, these analyses may have shortcomings with respect to how well they address the presence or absence of rare species. Researchers may delete rare species explicitly, or ignore them implicitly by the use of small sample sizes. The motivation for exclusion of rare species may be related to sampling or analytical resource limitations. The authors provide an overview of the importance of rare species, the sensitivity of the newer multivariate techniques to rare species, and the need for careful evaluation of the potential influences of the inclusion or exclusion of rare species from analyses in light of each study’s objectives and spatial scale.Nick Aumen,[email protected]Marty Gurtz,[email protected]Co-editors