Effects of emergence phenology, taxa tolerances and taxonomic resolution on the use of the Chironomid Pupal Exuvial Technique in river biomonitoring

Abstract

1. We studied chironomid communities of four rivers in south-eastern Finland, differing in their water quality, during summer 2004 using the Chironomid Pupal Exuvial Technique, CPET. The aims of the study were to (i) test the adequacy of the generic-level identification in the CPET method, (ii) define the emergence patterns of chironomid taxa classified as intolerant to organic pollution, (iii) assess the tolerance levels of intolerant chironomids and (iv) identify taxa most indicative of good water quality. 2. Procrustean rotation analysis indicated very strong concordance between the ordinations using either species or genus-level data, suggesting that generic-level identification of chironomids is adequate for biomonitoring based on CPET. However, when only a few taxa occur in great numbers, it may be advisable to identify these to the species level, especially if these taxa are important indicators of the impact in question. 3. The detection of a particular species may require accurate timing of sampling, whereas a species-rich genus might be detected throughout a season. Given that the emergence of chironomid species may vary from year-to-year and between sampling sites, community differences detected at the species level may be related to between-site variation in species' emergence patterns rather than true differences in species composition. 4. Indicator species analysis (IndVal) showed that the distribution and abundance of intolerant chironomid taxa differed strongly among the studied rivers. Some of the intolerant taxa were restricted to unimpacted conditions, whereas others occurred mainly in impacted rivers. Thus, the indicator status of some genera (e.g. Eukiefferiella, Parametriocnemus, Stempellinella and Tvetenia) needs reassessment.

Conochironomus (Diptera: Chironomidae) in Asia: new and redescribed species and vouchering issues

“…However, this technique often requires additional collection of adults, and does not generally provide association of the pupa. The latter stage has high value in systematics and descriptive taxonomy (Brundin 1966, Krosch & Cranston 2012) and biomonitoring (Raunio et al 2007), and it can provide barcode DNA (Krosch & Cranston 2012, Kranzfelder et al 2015. Fortunately, it is likely that the development of quick extraction methods (Kranzfelder et al 2016), Direct PCR (Wong et al 2014), and cheap NGS barcoding (Meier et al 2015) will rapidly increase the number of species with matched life history stages.…”

DNA barcodes and morphology reveal unrecognized species in Chironomidae (Diptera)

“…Immature life stages are important in biodiversity assessments of chironomids and biological monitoring (Anderson et al 2013;Ekrem et al 2010;Ferrington et al 1991;Kranzfelder et al 2015;Raunio et al 2007). In particular chironomid pupal exuviae might provide important characters to help resolve taxonomic issues for cryptic species complex.…”

Use of Chironomidae (Diptera) Surface-Floating Pupal Exuviae as a Rapid Bioassessment Protocol for Water Bodies

“…A variety of studies have used SFPE for taxonomic surveys (e.g., [13][14][15] ), biodiversity and ecological studies (e.g. 7,[16][17][18][19] ), and biological assessments (e.g., [20][21][22] ). Additionally, some studies have addressed different aspects of sample design, sample size, and number of sample events required for achieving various detection levels of species or genera (e.g., 8,9,23 ).…”