Globally, habitat change is one of the major drivers of biodiversity loss. Similar changes have occurred in Sweden over the past 150 years resulting in loss of habitat complexity at local and landscape scales.  In parallel, the climate is changing, with increasing air temperatures in the past 100 years. This changing climate will likely have knock-on effects on habitats and their microclimates.  Bats are often considered good indicators of environmental change. However, many bat species are declining globally with north European populations considered the most at risk due to climate change. The effects of habitat and climate change on bats are wide ranging and include loss of foraging habitat, impacts to roost locations, morphological changes and effects on their insect prey. In this thesis I identify how habitat and climate influence bat populations in Sweden, at multiple spatial and temporal scales.  Due to the complex nature of these drivers a multi-method approach was used, across a long latitudinal gradient in Sweden. To investigate the drivers of bat morphological change I analysed museum specimens over a 180-year time period together with historical maps, land-use statistics, and temperature data. To understand how habitat complexity at local and landscape scales influences bat activity, I monitored bats acoustically, sampled prey abundance and measured microclimate in a study focusing on forest borders. I also used a citizen science project to investigate bat diet and the local and landscape drivers of roost selection. I found no effect of climate change on bat morphology but jaw size changed over time in two bat species, with increasing jaw size in one species and decreasing in the other. In terms of microclimate, humidity was a strong driver of bat activity. As for effects of landscape level habitat, forest cover influenced wing morphology with bats having shorter, broader wings in more forested landscapes. Furthermore, area of deciduous forest had a positive effect on bat activity, roost selection and abundance of bat prey. At the local-scale forest structural complexity was important for bat activity but not for their insect prey. I also found high dietary overlap in the two most common species (Eptesicus nilssonii and Pipistrellus pygmaeus).  These findings highlight the need to maintain and increase deciduous forest cover and structurally complex forest borders within heterogenous habitats at local and landscape scales to meet the ecological needs of bats and their prey and ensure their conservation in the future.