The use of indicator taxa as representatives of communities in bioassessment

Abstract

1. Sampling and processing of benthic macroinvertebrate samples is time consuming and expensive. Although a number of cost-cutting options exist, a frequently asked question is how representative a subset of data is of the whole community, in particular in areas where habitat diversity is high (like Dutch surface water habitats). 2. Weighted averaging was used to reassign 650 samples to a typology of 40 community types, testing the representativeness of different subsets of data: (i) four different types of data (presence/absence, raw, 2 log-and ln-transformed abundance), (ii) three subsets of 'indicator' taxa (taxa with indicator weights 4-12, 7-12, and 10-12) and (iii) single taxonomic groups (n ¼ 14) by determining the classification error. 3. 2 log-and ln-transformed abundances resulted in the lowest classification error, whilst the use of qualitative data resulted in a reduction of 10% of the samples assigned to their original community type compared to the use of ln-transformed abundance data. 4. Samples from community types with a high number of unique indicator taxa had the lowest classification error, and classification error increased as similarity among community types increased. Using a subset of indicator taxa resulted in a maximum increase of the classification error of 15% when only taxa with an indicator weight 10-12 were included (error ¼ 49.1%). 5. Use of single taxonomic groups resulted in high classification error, the lowest classification error was found using Trichoptera (68%), and was related to the frequency of the taxonomic group among samples and the indicator weights of the taxa. 6. Our findings that the use of qualitative data, subsets of indicator taxa or single taxonomic groups resulted in high classification error implies low taxonomic redundancy, and supports the use of all taxa in characterising a macroinvertebrate community, in particular in areas where habitat diversity is high.

Assessment of eutrophication pressure on lakes using littoral invertebrates

“…In addition, stony substrata are likely to provide a more constant habitat type among seasons; resulting in less variation among communities and in time, compared with sites with soft substrata, which may vary significantly among seasons owing to macrophyte or microphytobenthos growth. This concurs with the results of others who found greater response of invertebrate communities to nutrients when stratified according to habitat type (Tolonen et al, 2001;Nijboer et al, 2005;Brauns et al, 2007).…”

Choice of macroinvertebrate metrics to evaluate stream conditions in Atlantic Forest, Brazil

“…Taxonomic identifications are central to biological assessment because many groups require difficult and time-consuming analysis for identification to the genus level or lower (Nijboer et al 2005), which may exceed the time and budget of most biomonitoring programs in tropical regions (Gardner et al 2008). Our findings in relation to the applicability of diversity indices show this challenge.…”

Benthic macroinvertebrate community structure in a stream of the north-west region of Paraná State, Brazil

“…Environmental impact may result in reduced biodiversity and changes in functional structure of this community (Kleine & Trivinho-Strixino 2005). The complex interactions between benthic fauna and the environment make these organisms useful tools in the evaluation of water quality and the development of biological indices (Nijboer et al 2005, Roche et al 2010. The use of these metrics for monitoring streams is in wide use today, and has been adapted to suit regional and local differences, especially when comparing preserved and impacted environments.…”