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The purpose of the study was to provide further knowledge about if the total amount of solar radiation during the marsh fritillary’s (Euphydryas aurinia) period for larvae development (April 15th – May 15th) and/or flying period (June 1st – June 30th) influenced the average of larvae colonies in the autumn at 12 sites in Dalarna County. Among increased temperatures, global climate models also predict an increased amount of solar radiation and a decrease in cloudiness in northern Europe, as a result of the climate changes. The marsh fritillary has declined rapidly, especially in the Northern of Europe and are in Sweden red-listed as vulnerable (VU). The marsh fritillary is a univoltine species who are dependent on open, sunny, and moist semi-natural grasslands with the hostplant devil’s bit (Succisa pratensis). The data over solar radiation was received from SMHI and had been measured in Borlänge over the last 14 years. The data over the number of larvae colonies was received from Länsstyrelsen Dalarna and had been measured over the last 15 years. The linear regression analysis for both the period of larvae development (p=0,58) and the whole period (p=0,07) indicates that during those periods the solar radiation did not influence the average of larvae colonies. However, the total amount of solar radiation during the flying period (p=0,02) influence the average of larvae colonies during the autumn.

The loss of biodiversity worldwide and methods of prevention are hot subjects receiving increased interest in todays’ research. Meadow construction in urban areas has been the focus of recent studies to increase both local and global biodiversity. In my report, I address potential analyses to conduct in advance before practical meadow constructions in a landscape. The subject I chose to focus on for this report was a LONA-project aimed to construct meadows on contemporary amenity grasslands in a semi-urban municipality. I used vegetation data from an inventory executed in 2021. Patches were in advance classified based on conditions observed during the inventory with class 1 obtaining the highest meadow potential, class 2 obtaining mediocre potential, and class 3 weak or no potential. I analysed vegetation data on species richness, environmental indicator values, and composition. Additionally, I analysed the soil types and historical land uses in the study area to display credible soil characteristics. The order of Lepidoptera was used as a model taxon for pollinators and the red-listed Marsh fritillary (Euphydryas aurinia) was separately analysed for conservational purposes. To illustrate the landscapes’ ability to facilitate the dispersal of butterflies, connectivity analyses of varying meadow construction scenarios were executed. Results indicate higher species richness on average per patch and more indicator species in class 1, suggesting a better starting point and making quality assessments more credible in comparison to class 2. Underlaying soil type seems to some extent to influence the meadow potential by affecting vegetation composition and hence butterfly occurrence in terms of host plant distribution. I could however not draw any conclusions from the effect of historical land use on current patch classifications, and consequently meadow potential. To facilitate for E. aurinia to widen its distribution in the study area, and to avoid local extinction, further conservational efforts should focus on mimicking the conditions and current management of the powerline corridor, that currently yields high diversity of butterflies and abundance of E. aurinia, to other powerline corridors in the study area. To facilitate dispersal of butterflies and other pollinators, target meadow areas of both class 1 and class 2 patches should be constructed to avoid patch isolation, as illustrated in the connectivity analyses. Further research is needed to investigate other factors possibly affecting suitability of grasslands for meadow construction.