Abundance and species richness patterns of diving beetles (Coleoptera, Dytiscidae) from exposed and protected sites in 98 northern Swedish lakes
✍ Scribed by Anders N. Nilsson; HÓakan Söderberg
- Publisher
- Springer
- Year
- 1996
- Tongue
- English
- Weight
- 394 KB
- Volume
- 321
- Category
- Article
- ISSN
- 1573-5141
No coin nor oath required. For personal study only.
✦ Synopsis
Forty species of predaceous diving beetles (Coleoptera, Dytiscidae) were collected in sweepnet samples from 98 boreal lakes in northern Sweden . Samples from protected sites with vegetation had significantly more specimens and species than those from exposed sites without vegetation in the same lakes . No geographically based differences, e .g . latitudinal or in distance from the coast, were found . These gradients were 200 and 150 km long, respectively. Species' distribution in terms of occurrence at number of sites was positively correlated with the mean abundance of the species . The relationship between species' abundance and body length was characterized by the lack of large, abundant species . Partial least square regressions on dytiscid abundance and species richness showed low predictive power of lake area, altitude and water chemistry . The seven environmental variables used explained at best 15 .3 and 24 .4% of the total variance in abundance and species richness, respectively . The results are compared to activity trap catches of dytiscids in lakes in an adjacent region . A majority of the species occurred in both materials . However, species occurring in high proportion in one of the materials, were rare in the other material . The mean body length of the species caught more efficiently with traps was not larger than that of those overrepresented in net sampling . Based on this study and the available literature data, the regional species pool of boreal lake dytiscids is estimated to 30-40 species . It is still an open question if lake dytiscid assemblages are markedly poorer than those found in smaller, more temporary waters . The species richness of lake assemblages is seemingly strongly connected with the development of vegetation, whereas the impact of water chemistry is small .