Effects of beaver dams on benthic macroinvertebrates

• Main Author: Johansson, Andreas
• Format: Others
• Language: English
• Published: Uppsala universitet, Institutionen för biologisk grundutbildning 2014
• Subjects: Biological Sciences; Biologiska vetenskaper
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-396803

In the 1870's the beaver (Castor fiber), population in Sweden had been exterminated. Thebeaver was reintroduced to Sweden from the Norwegian population between 1922 and 1939.Today the population has recovered and it is estimated that the population of C. fiber in all ofEurope today ranges around 639,000 individuals. The main aim with this study was toinvestigate if there was any difference in species diversity between sites located upstream anddownstream of beaver ponds. I found no significant difference in species diversity betweenthese sites and the geographical location of the streams did not affect the species diversity.This means that in future studies it is possible to consider all streams to be replicates despiteof geographical location. The pond age and size did on the other hand affect the speciesdiversity. Young ponds had a significantly higher diversity compared to medium-aged ponds.Small ponds had a significantly higher diversity compared to medium-sized and large ponds.The upstream and downstream reaches did not differ in terms of CPOM amount but somewater chemistry variables did differ between them. For the functional feeding groups I onlyfound a difference between the sites for predators, which were more abundant downstream ofthe ponds.