Motivation

Forest ecosystems have been threatened by global anthropogenic stressors, such as climate change and habitat degradation, with consequent loss in biodiversity and ecosystem function worldwide. Understanding the mechanisms that underlie the relationships between global changes, biodiversity and related processes is often hindered by the complexity of forest ecosystems. Replicated microcosm experiments provide suitable model systems to study such impacts because they are simple enough to allow studying the whole system, but sufficiently complex to derive results that can be applied to larger ecosystems. Impacts of forest management are being successfully accessed using freshwater microcosms, such as water filled tree holes, tank bromeliads and artificial tree holes. These microcosms are frequently inhabited by insects, crustaceans, nematodes, aquatic mites, protists, bacteria and fungi, which comprise an important community in forest ecosystems, affecting key ecosystem functions and services. Natural microcosms can hold up to 50,000 L of rain water per hectare in tropical forests and several litres of rain-water in temperate beech forests, thus acting as water source for many forest organisms and additionally provide important food resources for terrestrial organisms. Beside their importance for ecosystem functions in natural ecosystems, forest degradation can favour the development of mosquito-transmitted diseases in such ecosystems.