ABSTRACT1. Biodiversity is a central concept in conservation programme design. Until recently, ponds were neglected habitats probably owing to their small size and to the ignorance of their real conservation value. The classical theory of species-area relationship (SAR) might apparently support such a view by predicting low richness values in small habitat patches. SAR theory does not take into account the fact that groups of small habitat patches can significantly contribute to regional richness, regardless of their overall small area. This work intends to contribute to the SLOSS (single large or several small) debate with data on littoral macroinvertebrates from mountain ponds. Do groups of small ponds support communities with higher biodiversity than a single large lake?2. Littoral macroinvertebrate richness, both local and regional, were measured in 17 ponds and one large lake from Sanabria Natural Park (NW Spain). In order to guarantee valid comparisons among systems, observed and estimated richness, as well as rarefaction methods were used.3. Although local richness in the lake was much higher than in any single pond, regional richness of ponds widely exceeded the value measured in the lake regardless of their small overall area. Six to seven ponds were enough to obtain an accumulated average richness equivalent to that in the lake.4. This pattern may be caused partly by increased habitat heterogeneity as proposed by the niche theory. Metacommunity theory might help to explain the high regional richness measured in the group of ponds in the study area.5. Whatever the explanation, it is evident that groups of mountain ponds strongly contribute to regional richness, a conclusion that should be taken into account by management programmes. There is a gap in this respect in European legislation (the EC Habitats Directive and Water Framework Directive), which fails to include groups of ponds as an additional habitat category.
This study was aimed at determining the performance of some indices and community attributes frequently used to assess river quality and test the role of macroinvertebrate taxa richness as element of bioindication in several coastal tropical streams of western Esmeraldas (Ecuador). In addition, a macroinvertebrate taxon list of this region was provided for the first time. Thirteen sampled points distributed across nine streams were selected for this study and nineteen parameters and attributes of bioindication were tested. The differences between nonimpact and impact places were evaluated mainly using one-way analysis of variance. Jackknife 2 and Clench were used to estimate the regional richness and the quality of the inventory, respectively. Seventy taxa (principally genus and family) of the main groups of macroinvertebrates were collected. Measured richness and family richness were the best metric followed by Biological Monitoring Working Party/Colombia (BMWP/Col), Odonata richness, Shannon-Weiner, and EPT richness (Ephemeroptera + Plecoptera + Trichoptera) indices. Only a slight right trend (Ephemeroptera, Trichoptera, and Chironomidae attributes) or incorrect performances (Average Score Per Taxon (ASPT) and % EPT) were showed by frequently used metrics. Finally, several recommendations were made about taxonomic level used, the ranks of quality of taxa richness, and the effort-results relationship in the field of bioindication.
-Complete inventories of the fauna at a given place, for a specific community or geographical area are often exceedingly hard to get. In recent years a number of estimation techniques have emerged that can be used to extrapolate from these samples to the true number of species in an area. These estimation models are based on different mathematical approaches and can be classified as either species accumulation curves or nonparametric estimators (Brose et al., 2003, Ecology, 84, 2364-2377. In this paper, we have tested the performance of some of the richness estimators on nineteen mountain ponds in Castilla y Leo´n (Spain) in order to provide guidance on their potential use in future researches. We collected benthic macroinvertebrate of these ponds from the littoral zone with a pond net by kicking and sweeping. Ten-second samples were collected in each pond up to a total time of 3 to 5 minutes per pond, depending on the pond size. In addition, two of the ponds, were sampled in 2004, 2006 and 2007 providing a three-year time series. The results of this study showed that Jackknife 2 was the best of the evaluated methods based on all chosen criteria and also performed well across all studied ponds. Jackknife 1, Chao 1 and Chao 2 also presented good results and they were inferior to Jackknife 2 mainly because of the requirement for larger sub-sample sizes.
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