Effects of sampling microhabitats with low coverage within the STAR/AQEM macroinvertebrate sampling protocol on stream assessment

Abstract

In the STAR/AQEM protocol microhabitats covering less than 5% of the sampling area were neglected. Driven by an ongoing discussion on the importance of these underrepresented microhabitats we tested the influence of sampling them. We investigated 48 streams representing 14 different stream types from all over Germany. Macroinvertebrates of underrepresented microhabitats were sampled in addition to the STAR/AQEM protocol. To ensure the method remains feasible in routine monitoring programmes the total sampling and sorting effort of additional sampling was limited to 20 min. Particularly those taxa were picked, which were not recognised during the routine STAR/AQEM sorting.To identify the effect of additional sampling on stream assessment results, we calculated the stream type-specific Multimetric Index (MMI) with the ''main'' and the ''main+additional'' data for each sample. The mean and median difference in MMI values between ''main'' and ''main+additional'' samples was 0.02 and 0.01, respectively. In seven of 48 samples (14.6%) a different ecological quality class was calculated with the ''main+additional'' dataset. Regarding common metrics within the MMI as well as intercalibration metrics differences between ''main'' and ''main+additional'' samples were analysed. The values differed most in richness metrics (e.g., number of EPTCBO Taxa, number of Trichoptera Taxa). The results of the present study show that additional sampling of underrepresented microhabitats could alter multimetric assessment results.

Habitat‐oriented Sampling of Macroinvertebrates Affects the Determination of Ecological Status in Temporary Mediterranean River Systems

“…There appear to be very few studies on the effect of under-represented lotic habitats and the influence of additional taxa in biological assessment. However, Haase et al (2009) also found that multimetric assessment results were affected by sampling 'additional' microhabitats with low coverage across 48 sampling sites in Germany using the STAR/AQEM sampling protocols. Interestingly, Bonada et al (2006) compared two different macroinvertebrate sampling methodologies in Mediterranean stream systems on two different continents and found that they produced very similar results, expressed via metrics.…”

“…However, Haase et al . () also found that multimetric assessment results were affected by sampling ‘additional’ microhabitats with low coverage across 48 sampling sites in Germany using the STAR/AQEM sampling protocols. Interestingly, Bonada et al .…”

“…The aim of biomonitoring sampling protocols, such as benthic macroinvertebrate sampling, is to obtain a representative sample of the target community at a given site using a repeatable, standardized methodology (Haase et al, 2009;Gabriels et al, 2012). Although sampling protocols differ in the type of sampling gear used, collection methods, sampling area, the number of replicates and sampling effort, the data obtained (structural or functional diversity, relative abundance, scores derived from the presence/absence or abundance of given indicator species) are used to calculate metrics that provide information, together with data on hydromorphological and physicochemical support elements, on ecosystem health.…”

“…Most macroinvertebrate sampling protocols, including many developed for the WFD, are based on information taken from a composite sample rather than a sample based on the collection of individual replicates (Haase et al, 2009;Gabriels et al, 2012). The Portuguese WFD benthic macroinvertebrate sampling protocol for rivers (INAG, 2008), an adaptation of the AQEM protocol, comprises a composite sample of six 1 × 0.25 m subsamples collected with a hand net in proportion to the presence and extent of four inorganic and two organic microhabitat types in the sampling area (refer to Hering et al, 2004).…”

Lessons from practice: assessing early progress and success in river rehabilitation

“…Natural variation has been demonstrated to reduce the sensitivity of macroinvertebrate indicators to change (Clarke et al, 2006;Blocksom & Flortmersch, 2008). Variability in relation to space, time and sampling methods have been stated as significant factors that result in difficulties in identifying significant change in macro-invertebrate monitoring (Brooks et al, 2002;Sporka et al, 2006;Haase et al, 2008). The results suggest that macroinvertebrate indicators maybe too insensitive to consistently identify early progress following river rehabilitation interventions.…”