Fish is considered to be a keystone predator in freshwater habitats. Several studies have shown that the species composition of odonates (Odonata) is different between habitats with and without fish, and that odonates depending on the behaviour and physical characteristics of the individual species react differently to the presence of fish, some positively, some negatively and others not at all. This study aims to study the effect of fish as predators on the odonate community, and especially the little studied effect of the presence and composition of different ecological groups of fish in lakes. 92 Swedish lakes were surveyed for abundances and species compositions of odonates. The composition of fish species in the lakes was determined from official sources and divided into seven ecological groups. While several of the tests for potential interactions between fish and odonates resulted in no significance, the discrimination analyses of the different ecological groups of fish tested against odonate species composition did reveal high classification coefficients, indicating that different ecological groups have different odonate communities. Number of species of fish did also have a fairly high classification coefficient in a discriminant analysis. A combined plot show that two categories of lakes are separating from the others in odonate composition. Both these categories lacked some littoral groups of fish, indicating that littoral fish species may have a strong influence on the odonate community. The study also concluded that both lake size and latitude are potential confounding variables.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:hh-4216 |
| Date | January 2006 |
| Creators | Andersson, Daniel |
| Publisher | Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Högskolan i Halmstad/Sektionen för Ekonomi och Teknik (SET) |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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