Vårvädrets påverkan på brun gräsfjäril (Coenonympha hero) i Dalarnas län

Sammanfattning

Biodiversity loss is a global problem, with climate change being one of the main drivers. Butterflies are a particularly vulnerable group of organisms, and the scarce heath butterfly (Coenonympha hero) is a species showing a reduction in the number of reproductive individuals in parts of its range. The aim of this study was to investigate whether solar radiation and precipitation during the spring (mars–may) affect the abundance of the scarce heath butterfly during the summer. The analysis was based on 294 data points from 29 locations in Dalarna County, Sweden, and the surveying was conducted between years 2014–2025 by The County Administrative Board of Dalarna. The data were analyzed using a generalized linear mixed effects model with negative binomial distribution, where four biologically motivated models were compared using the Akaike Information Criterion (AIC). The results showed that neither solar radiation nor precipitation during the spring explained the variation in the abundance of the scarce heath butterfly. However, approximately 37 % of the variation could be explained by differences between locations. The results suggest that local habitat conditions are more important for the abundance of the scarce heath butterfly than regional weather conditions, such as solar irradiance and precipitation, during the spring. The study highlights the importance of including microhabitats and local habitat conditions in future studies and conservation efforts, to better understand the ecological needs of the species and thereby enable effective conservation work in a changing climate.