Abstract
We will base our study on climate induced biodiversity shifts in freshwater ecosystems on three influential hypotheses: the intermediate disturbance hypothesis, the chaos and biodiversity hypothesis and the alternative stable state hypothesis. According to the 'intermediate disturbance hypothesis', biodiversity is highest at intermediate disturbance levels. Climatic variability is an important component of disturbance in aquatic ecosystems. Climate change can thus be expected to affect biodiversity by changing the disturbance regime. According to the 'chaos and biodiversity hypothesis' internally driven oscillations may also be critical for maintaining biodiversity. According to this hypothesis climate change is likely to affect biodiversity by changing the physiology of the individual species. According to the 'alternative stable state hypothesis', lakes can switch in an abrupt way between alternative stable states which differ strongly in community composition as well as biodiversity. Climate change may potentially push these ecosystems to another stable state and may therefore have a large effect on aquatic biodiversity. We will review, test and apply each of these theories in two closely linked projects. A mathematically inclined Ph.D. student will perform time series analysis on existing long term datasets and perform analyses with simple multi-species prey-predator, competition and ecosystem models. An experimentally experienced post-doc will test the generated hypotheses in microcosm experiments and additionally carry out simulations with full-scale ecosystem models. These two ALW-funded researchers will work in a broad consortium composed both of national and international leaders in the field of biodiversity and ecosystem functioning of aquatic systems. The consortium also includes national key-players in the field of water quality and water management. The anticipated results will provide the first essential tools to assess the potential impact of climate change on aquatic biodiversity. The integrative approach of the programme will contribute to a better understanding of the mechanisms by which biodiversity is obtained, which is essential for the development of sustainable management strategies. It will also contribute to a better prediction of the effects of global change for aquatic biodiversity.
Netherlands