Större och mindre växtätares samexistens : Möjlig interaktion och effekt på lokal biodiversitet

• Main Author: Nyman, Jimmy
• Format: Bachelor Thesis
• Language: Swedish
• Published: UmeÃ¥ universitet, Institutionen för ekologi, miljö och geovetenskap 2015
• Subjects: Ecology; Ekologi; Alces alces
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-105691

The purpose of this report was to investigate to which extent local presence of large herbivore mammals (Alces alces, Cervus elaphus, Capreolus capreolus, Dama dama and Sus scrofa) covaries with small rodents (Myodes glaerolus, Apodemus flavicollis and Apodemus sylvaticus? The hypothesis was that high abundance of wild ungulates would inhibit the density of small forest rodents. The data was collected during field work within FoMA (Environmental Monitoring Assessment)/SLU (Swedish University of Agricultural Science). The Ungulate dropping inventory and rodent trappings, which is the base in this report, where performed 2012 – 2014 in Gnesta/Nyköping municipalities (G/N) with a relatively high density of wild ungulates and Vetlanda/Växjö municipalities (V/V) with relatively lower wild ungulate density. The results indicates that in the G/N area, forest rodent populations where less abundant than in the V/V area. It also shows that within some local areas (1*1 km) in G/N, with high wild ungulate dropping rate, the rodent catch frequency is lower than in areas with low wild ungulate dropping rate. Therefore, high wild ungulate populations may according to this study, affect local rodent populations. Due to this, wild ungulates also may affect the ecosystem on several other trophic levels. Inhibited rodent populations could on the second hand affect the specialist predators such as Tengmalm´s Owl (Aegolius funereus), pygmy owl (Glaucidium passerinum) and long-Eared Owl (Asio otus). High densities of wild ungulates may also affect plant recruitment of oak (Quercus robur and Quercus petraea) through high predation on seedlings and acorns. Rodents change the spatial pattern of their acorn caches and hence oak recruitment is negatively affected. However, more scientific effort is needed to get a clearer picture on this topic.