Macroinvertebrate indicators of lake acidification: analysis of monitoring data from UK, Norway and Sweden

Abstract

Although the acid sensitivity of many invertebrate species in lakes is well known, methods for assessment of lake acidification based on macroinvertebrate samples are less developed than for rivers. This article analyses a number of existing metrics developed for assessment of river acidification, and evaluates their performance for assessment of lake acidification. Moreover, new species-based indicators of lake acidification were developed and tested. The selected dataset contains 668 samples on littoral macroinvertebrates from 427 lakes with almost 60% of the samples from Sweden and the rest from UK and Norway. Flexible, non-parametric regression models were used for explorative analyses of the pressureresponse relationships. The metrics have been assessed according to their response to pH, the degree of nonlinearity of the response and the influence of humic compounds. Acid-sensitive metrics often showed a threshold in response to pH between 5.8 and 6.5. Highly acid-tolerant metrics were typically dominant across the whole pH range. Humic level had a positive effect for most acid-sensitive metrics. Generally, most metrics showed a more non-linear response pattern for the humic lakes than for clear lakes. The significant relationship between these macroinvertebrate metrics and acidification shows that there is a potential for developing further the assessment systems for ecological quality of lakes based on these metrics, although the metrics explained a low % of the variation (\30%). In order to improve the predictive power of the biotic metrics across the acidified part of Europe, further harmonization and standardisation of sampling effort and taxa identification are needed.

Interactions between pH and nutrients on benthic algae in streams and consequences for ecological status assessment and species richness patterns

“…Similarly, acid deposition has not, until now, been explicitly included in screening protocols for reference sites (e.g. Pardo et al, 2012) whereas our evidence with respect to surface water pH suggests that it may affect "expected" index values not just for benthic algae but also for other taxonomic groups known to respond to both nutrient/organic and acid pressures (Bennett et al, 2011;Moe et al, 2010;Schartau et al, 2008). Note that Sweden, UK and Norway all excluded sites known to suffer anthropogenic acidification from the dataset reported in .…”

Ecological threshold responses in European lakes and their applicability for the Water Framework Directive (WFD) implementation: synthesis of lakes results from the REBECCA project

“…The paper by Schartau et al 2008 therefore evaluated the applicability of existing metrics developed for assessment of river acidification to lakes. Further lake-specific indicators of acidification were also developed and tested.…”

“…Acid-sensitive macroinvertebrate indicators often showed a threshold at pH between 5.8 and 6.5 (Schartau et al 2008), with a positive effect of humic matter for most of the acidsensitive indicators. Fish in humic waters can also tolerate higher acidity (lower pH) than fish in clear waters, similarly to invertebrates, mostly due to lower toxicity of Al in humic waters.…”

“…Also, data on response of benthic invertebrates to acidification (Schartau et al 2008) have been extensively used by the Northern GIG countries to select relevant indicators for use in class boundary setting and intercalibration for this biological element.…”

Rapid Bioassessment of Magura haor (Floodplain wetland), Cachar District, Assam, India using Aquatic Insects

“…Resident biota in water body are natural monitors of environmental quality and can reveal the effects of episodic as well as cumulative pollution and habitat alteration 5 . Biotic indices such as Trent Biotic index 6 ; BMWP score 7 , ASPT score 7 , Wisconsin Biotic Index (BI) and Family Biotic Index (FBI) for macro-invertebrates are used to detect and monitor water quality and human perturbations in varying ecosystems like streams 8 , rivers 9 and lakes 10 .…”