Recent climate change is recognized as a main cause of shifts in geographical distributions of species. The impacts of climate change may be aggravated by habitat fragmentation, causing regional or large scale extinctions. However, we propose that climate change also may diminish the effects of fragmentation by enhancing flight behaviour and dispersal of ectothermic species like butterflies. We show that under weather conditions associated with anticipated climate change, behavioural components of dispersal of butterflies are enhanced, and colonization frequencies increase. In a field study, we recorded flight behaviour and mobility of four butterfly species: two habitat generalists (Coenonympha pamphilus; Maniola jurtina) and two specialists (Melitaea athalia; Plebejus argus), under different weather conditions. Flying bout duration generally increased with temperature and decreased with cloudiness. Proportion of time spent flying decreased with cloudiness. Net displacement generally increased with temperature. When butterflies fly longer, start flying more readily and fly over longer distances, we expect dispersal propensity to increase. Monitoring data showed that colonization frequencies moreover increased with temperature and radiation and decreased with cloudiness. Increased dispersal propensity at local scale might therefore lower the impact of habitat fragmentation on the distribution at a regional scale. Synergetic effects of climate change and habitat fragmentation on population dynamics and species distributions might therefore appear to be more complex than previously assumed.
Cities are growing rapidly. It takes a chain of activities to get food from farms to cities. This food system is largely driven by autonomous market development, seizing opportunities favourable to a stakeholder but unfavourable to society at large. Spatial planning is crucial along the chain of food system activities to improve food system outcomes, resilience, and limit negative trade-offs. To include the food system in spatial planning, it must first be mapped (i.e., spatialisation) to understand the functions. These maps inform the spatial planning process, which in turn influences spatial configuration of activities. This paper explores the role of spatialisation and spatial planning in the food system of the fast-growing Dhaka Metropolitan Area (DMA) using three different approaches: urban footprint, mapping, and semi-structured interviews. Stakeholders are unaware of spatial aspects that are present in DMA’s food system and therefore do not consider it while developing spatial plans. The analysis in this article, based on the Urban Food Footprint analysis, food system spatialisation, and interviews shows that spatial planning informed by descriptive spatial information can play an important role in guiding the transformation to a more robust, resilient, and inclusive food system.