Freshwater diatom and macroinvertebrate diversity of coastal permanent ponds along a gradient of human impact in a Mediterranean eco-region |
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Authors: | Valentina Della Bella Laura Mancini |
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Institution: | (1) Department of Environment and Primary Prevention, National Institute of Health, Viale Regina Elena 299, 00161 Rome, Italy |
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Abstract: | Mediterranean coastal areas are characterised by heavily transformed landscapes and an ever-increasing number of ponds are
subjected to strong alterations. Although benthic diatoms and macroinvertebrates are widely used as indicators in freshwater
ecosystems, little is still known about the diatom communities of lowland freshwater ponds in the Mediterranean region, and,
furthermore, there are few macroinvertebrate-based methods to assess their ecological quality, especially in Italy. This article
undertakes an analysis of benthic diatom and macroinvertebrate communities of permanent freshwater ponds, selected along a
gradient of anthropogenic pressures, to identify community indicators (taxa and/or metrics) useful to evaluate the effect
of human impacts. A series of 21 ponds were sampled along Tyrrhenian coast in central Italy. Five of these ponds, in a good
conservations status and surrounded by woodland were selected as ‘reference sites’ for macroinvertebrates and epipelic diatoms.
The remaining sixteen ponds were located in an agricultural landscape subject to different levels of human impact. The total
number of macroinvertebrate taxa found in each pond was significantly higher in reference sites than in both the intermediate
and heavily degraded ones, whereas the diatom species richness did not result in a good community variable to evaluate the
pond ecological quality. The analysis revealed a substantial difference among the compositions of diatom communities between
reference ponds and degraded ponds. The former were characterised by the presence of several species belonging to genera,
such as Pinnularia sp., Eunotia sp., Stauroneis sp., Neidium sp., all of which were mostly absent from degraded ponds. Furthermore, the taxonomic richnesses of some macroinvetebrate
groups (Odonata, Ephemeroptera, Trichoptera, Coleoptera), and taxa composition attributes of macroinvertebrate communities
(total abundance, percentages of top three dominant taxa, percentages of Pleidae, Ancylidae, Hirudinea, Hydracarina) significantly
correlated with variables linked with anthropogenic pressures. The results of the investigation suggested that diatoms tended
more to reflect water chemistry through changes in community structure, whereas invertebrates responded to physical habitat
changes primarily through changes in taxonomic richness. The methodologies developed for the analysis of freshwater benthic
diatom and macroinvertebrate communities may have a considerable potential as a tool for assessing the ecological status of
this type of water body, complying with the European Union Water Framework Directive 2000/60/EC.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Guest editors: B. Oertli, R. Cereghino, A. Hull & R. Miracle
Pond Conservation: From Science to Practice. 3rd Conference of the European Pond Conservation Network, Valencia, Spain, 14–16
May 2008 |
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Keywords: | Algae Bacillariophyceae Macrofauna Lowland ponds Environmental modifications and land cover conversions Pond conservation status |
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