Spillningsinventering av brunbjörn i väglöst land: Ett kompletterande arbetet till Länsstyrelsens björnspillningsinventering i Västerbotten år 2014
Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
The lack of information regarding the distribution of Ursus arctos arctos in the mountains of Västerbotten, Sweden, has led to many important questions about the occurrence of bears in these areas. Species distributions models, like MaxEnt, have shown to be a useful tool in species management. The objective of this study was therefore to determine if the distribution of bears in the southern part of the mountain range in Västerbotten could be predicted with MaxEnt. Data on the distribution of bear droppings were collected in the study area and used together with environmental variables. The resulting model had an AUC-value of 0,76, which is considered as good from a statistical point of view. Logistic regression over transect sampels in the study area was used to determine which variables that were most important to the species distribution. The regression gave no reliable results because the number of observations was too low. However, the method could yield valuable information if the sampel size is large enough. A field study to collect droppings from bears were made in Girifjället (where the probability of finding traces of bears was particulary high according to the MaxEnt analysis). No droppings were found in the area, but droppings were collected during the field study in an area with lower prediction value (but still relatively high). This leads to the conclusion that this method, with a few modifications, could be used together with logistics regression to get a better understanding of the distribution of bears in remote areas.
Place, publisher, year, edition, pages
2014. , 27 p.
Brown bear, distribution map, collecting of feces, MaxEnt, Logistic regression
IdentifiersURN: urn:nbn:se:umu:diva-96309OAI: oai:DiVA.org:umu-96309DiVA: diva2:764008
Länsstyrelsen i Västerbotten
Bachelor of Science in Biology and Earthscience
Englund, Göran, Professor
Brodin, Tomas, Forskarassistent