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2. Biodiversity of macro-invertebrates in acid-sensitive waters: trends and relations to water chemistry and climate. ICP Waters report 127/2016

Author

Velle, Gaute, Mahlum, Shad, Monteith, Don T., de Wit, Heleen, Arle, Jens, Eriksson, Lars, Fjellheim, Arne, Frolova, Marina, Fölster, Jens, Grudule, Natalja, Halvorsen, Godtfred A., Hildrew, Alan, Hruška, Jakub, Indriksone, Iveta, Kamasová, Lenka, Kopáček, Jiří, Krám, Pavel, Orton, Stuart, Senoo, Takaaki, Shilland, Ewan M., Stuchlík, Evžen, Telford, Richard J., Ungermanová, Lenka, Wiklund, Magda-Lena, Wright, Richard F., and de Wit, Heleen - Project manager

Subjects
Forsuring / Acidification, Vannkjemi / Water chemistry, Biologisk mangfold / Biodiversity, Klima / Climate, Matematikk og Naturvitenskap: 400 [VDP]
Abstract

This is a study of the international impact of acid emission reductions on vulnerable freshwater biodiversity of benthic macroinvertebrates. In order to properly attribute impacts it is necessary to also incorporate the potential effects of changes in temperature and precipitation. Most sites show an increasing number of species towards the present. This can be attributed to a decrease in acidification, while temperature has a secondary influence on diversity. We expect that the biodiversity will continue to increase in the future as acid deposition decreases. The widespread response of aquatic diversity resulting from emission reductions of acidifying components to the atmosphere demonstrates the potential of international policy for achieving positive effects on the state of the environment. Norwegian Environment Agency (Miljødirektoratet) United Nations Economic Commission for Europe (UNECE)

Published
2016

3. Biodiversity in freshwaters: temporal trends and response to water chemistry (ICP Waters report 114/2013)

Author

Velle, Gaute, Telford, Richard J., Curtis, Chris, Eriksson, Lars, Fjellheim, Arne, Frolova, Marina, Fölster, Jens, Grudule, Natalja, Halvorsen, Godtfred A., Hildrew, Alan, Hoffmann, Andreas, Indriksone, Iveta, Kamasová, Lenka, Kopáèek, Jiøí, Orton, Stuart, Krám, Pavel, Monteith, Don T., Senoo, Takaaki, Shilland, Ewan M., Stuchlík, Evžen, Wiklund, Magda-Lena, de Wit, Heleen, Skjelkvaale, Brit Lisa, and de Wit, H. - Project manager

Subjects
monitoring, akvatisk fauna, aquatic fauna, Matematikk og naturvitenskap: 400 [VDP], biodiversitet, acid deposition, overvåking, sur nedbør, respiratory system, human activities, biodiversity
Abstract

This report describes trends in biological diversity of benthic invertebrates from acid-sensitive lakes and rivers sampled between 1982 and 2011 in the Czech Republic, Germany, Latvia, Norway, Sweden and the UK. The results indicate an overall increase in species diversity during the study period, especially in the rivers. The increase in biodiversity is correlated with declining sulphate concentrations in surface waters, which in their turn are related to reduced atmospheric deposition of sulphur. The changes in biodiversity could be related chemical recovery of surface waters, where reduced sulphate concentrations are associated with increased pH and lowered aluminium concentrations. Apart from the increasing species diversity seen in most sites, the biological recovery trends varied among sites. As a consequence of increased species diversity, the aquatic ecosystems are likely to have a higher resilience against future threats. We can expect an analogous increase in species diversity for comparable sites elsewhere. The improved biodiversity in acid-sensitive waters is in contrast to the world-wide trend of decreasing freshwater species diversity. Our results suggest that international policies to reduce sulphur emissions have promoted a positive development in species diversity of invertebrates in acid-sensitive surface waters. Norwegian Environmental Agency

Published
2013

11. Field experiments on flow refugia in streams

Author

Hildrew, Alan G., Orton, Stuart E., Winterbottom, Julie H., and Lancaster, Jill

Abstract

1. Field experiments were carried out to determine whether animals move into areas of low shear stress during periods of peak flow and therefore avoid hydraulic disturbance. 2. Flow at the scale of 0.05 m2 patches was reduced experimentally by creating artificial 'refugia'. Invertebrate colonization of cages with 1.1 mm mesh sides,which provided such potential refugia by reducing hydraulic forces within the cage, was compared with colonization of cages with coarser (15 mm) mesh which did not restrict the flow. 3. Colonization of these cages was tested over a series of weekly periods in two different stream. Nine trials were completed in a stream with abundant natural flow refugia (Broadstone Stream, SE England), and during three of these trials strong spates occurred. Six trials were completed in a stream with comparatively few natural flow refugia. (Dargall Lane, SW Scotland), and peak flows were relatively less. 4. In Broadstone Stream, the relative colonization of refugium cages was greatest during periods of peak flow, suggesting animals had used these low-flow areas as refugia during spates. Use of the artificial refugia did not occur inDargall Lane, at least at the flows achieved during the trials. 5. Our results are consistent with the hypothesis that stream invertebrates accumulate in refugia during high flow disturbances. Whether theirdistribution among patches is altered by active or passive means remains unclear. [ABSTRACT FROM AUTHOR]

Published
1997

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