Epsilon Archive for Student Projects

Abstract

Rising temperatures lead to species range shifts and thermophilisation of communities. Forests buffer temperatures and can provide relatively cool microclimates. These microclimates could act as refugia for cold adapted plant species facing the pressure of climate change. As forest microclimates are dependent on stand characteristics, forest management plays an important role in shaping them. This thesis explores the microrefugia potential on the forest ground in three Swedish regions and asks two main questions: First, where can relatively cold microclimates be found and what factors contribute to the difference in temperature? Second, where are cold communities located, and do they occur in cold microclimates? For analyses multiple linear regression models were used to explore microclimate temperature at 15 cm above ground and its drivers. The relationship between temperature and plant communities on the ground was investigated using correlation tests. Temperature and soil moisture data were obtained from microclimate loggers and plant occurrence from vegetation inventories. Additionally, predicted temperature maps were created based on open-source data on landscape features, microclimate temperature and linear models. Moreover, the microclimate models based on in-situ predictors and models with mapped predictors were compared. The relatively cold microclimates in the research areas were mainly driven by elevation, soil moisture and canopy openness. Cold plant communities were found in cold places, but there was no significant correlation with temperature along microclimate gradients within the individual regions. This could reflect limitations of the CTI (Community temperature index) as measurement for relative cold/warm adaptation of the ground plant communities. Future studies could focus on absence/presence of species close to the warm edge of their range, which may result in stronger correlations. Nevertheless, the study highlights that forest management can facilitate relatively cold places, which could be used for climate change adaption and mitigation strategies in boreal forests. Additionally, the results show that national scale data might be a helpful tool to incorporate microclimates in management and planning.