The purpose of this study was to investigate how elevated levels of heavy metals affect the faunal species composition, abundance and species-diversity. The bentic macroinvertebrate fauna in the highly polluted lake Tisken was compared with the bentic macroinvertebrate fauna in the unpolluted lake Varpan. Mine wastes account for most of the metal that is discharged into Tisken. The hypotheses was that the heavy metal pollutions in lake Tisken influenced the species composition, abundance and diversity of the Macroinvertebrates. Twenty samples were taken in both sites.

Abstract The benthic macroinvertebrate fauna of 22 natural springs on Öland was sampled, by using a time-standarized kick/sweep sampling technique, in the end of September and early October. The aim was to determine the number of species and their abundances in the macroinvertebrate communities in springs and how/why these may change between different springs. Likewise there was a purpose to investigate possible differences between springs considering the proportions of the number of species and the abundances of the five functional feeding groups; shredders, collectors, filter-feeders, scrapers and predators. There was also an aim to investigate if the distances betweeen springs had any influence on similarity between the communities of benthic Macroinvertebrates of the springs. Analysis from the springs collected material showed several interesting patterns in the number of species and their abundances when compared between springs devided into groups depending on their environmental factors such as depth and pH.

Predation is one of many factors that form the structure of the macroinvertebrate community in lakes, wetlands and watercourses. Earlier studies lack an examination concerning how fish- and waterfowl predation affect Macroinvertebrates during shorter periods in the spring. I performed an exclosure study in the shallow eutrophic Lake Tåkern which is located in the western part of Östergötland County, Sweden. The experiment was performed during a three week period (1-21 April 2012) when the water temperature was low and the density of migrating diving ducks was high. The experimental cages used included three out of four different treatments; general predation (open cages), bird exclusion (net with mesh size 90*45mm) and no predation (net with mesh size 1*1mm).

In this study the practical work with the EU Water Framework starts on the island of Gotland. 33 lakes and 32 streams have been characterized and classified regarding to their ecological status. The aim with the characterisation is to create a uniform discription of all waterbodies and a comparable estimation for the future. The aim with the classification is both to study the waterbodies ecological status and to gain knowledge of where the resources should be concentrated so that the ecological status in all waterbodies will be good in 2015.The characterisation has been done according to the EU Water Framework Directive, and the factors that have been applied are the mean depth and area of the lake. The length and size on the catchment area are the factors that have been used on streams.