FOREST LANDSCAPE STRUCTURE OF CAPERCAILLIE (TETRAO UROGALLUS) LEK SITES IN NORTHERN SWEDEN : Analysis of lek site characteristics

• Main Author: Blomgren, Agnes
• Format: Bachelor Thesis
• Language: English
• Published: Umeå universitet, Institutionen för ekologi, miljö och geovetenskap 2023
• Subjects: capercaillie (Tetrao urogallus); habitat selection; forest landscape structure; lek site; Ecology; Ekologi; Norra Sverige; Northern Sweden
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-209511

The purpose of this study is to analyze which variables influence the capercaillie’s (Tetrao urogallus) selection of lek sites in northern Sweden by using remote sensing data. The lek site is a crucial area for the species’ reproductive success. Studies outside of northern Sweden have confirmed that the landscape structure highly influences the selection of lek sites. This study examines whether the type of vegetation, forest volume and proximity to anthropogenic disturbances influence the selection of lek sites. The findings can be used to create a prioritizing map of northern Sweden to aid in conservation management and improve future inventories. 58 lek sites within five different counties were analyzed by a use-availability design, using a generalized linear mixed model with a binary distribution of the dependent variables. The vegetation types of pine forest, wet pine forest, continuous pine forest, mixed coniferous forest and wet other mixed forest were preferred by capercaillie, while other mixed forest, mire, continuous other forest, young forest, and clear cuts were avoided. Wet pine forest was the only vegetation type that had higher probability (36%) to be chosen over pine forest. For forest volume, the probability of being chosen increased with 22 % for each additional unit (m3/ha). For distance to buildings and roads, the probability of being chosen increased with 10 % for each additional unit of distance. I conclude that vegetation type, forest volume and proximity to anthropogenic disturbances influence the capercaillie selection of lek sites in northern Sweden.