Das Projekt "Determinants of microfauna community structure and multi-trophic diversity effects on ecosystem functioning in natural bromeliad mesocosms" wird vom Umweltbundesamt gefördert und von University Vancouver, Department of Zoology durchgeführt. This study examined food webs within bromeliad plants in Costa Rica to reveal general mechanisms maintaining species diversity and to predict consequences of species extinctions for the functioning of ecosystems. Humans are responsible for the destruction of pristine ecosystems around the world, causing large-scale extinctions of animal and plant species. However, we still lack the basic knowledge of the mechanisms that allow species to coexist in the first place. Furthermore, with each species that goes extinct, the interactions and functions of this species in the ecosystem are lost as well. For example, we know that plant species loss leads to lower plant productivity in hay meadows and forests. But how species extinctions at one level in the food web might affect ecosystem functions at other levels has rarely been studied. My work will improve the knowledge base of dramatically understudied tropical diversity and of microfaunal and 'brown' (decomposition-based) food webs. In a more general sense, identifying the mechanisms maintaining natural diversity will ultimately contribute to a better protection of species and potentially to a halt in their decline. In addition, by studying effects of species loss on ecosystems this study will help to predict and alleviate negative consequences of species extinctions. Because most ecosystems provide functions that are essential to humans, this research will ultimately benefit us. The model systems of this study were bromeliads in Costa Rica. These plants accumulate water in their leaf-formed tanks, which is inhabited by a number of species of aquatic algae, microscopic animals (microfauna) and larger insect larvae that help the bromeliad to decompose waste material and acquire nutrients. By conducting controlled experiments with natural bromeliads I examined general mechanisms allowing species to coexist and thus maintaining the structure of communities and their diversity. Furthermore, I quantified nutrient flows in the system and measured effects of species loss at high levels (predatory insect larvae) and low levels (resources) of the bromeliad food web on species interactions and nutrient transfer to the plant. More details can be found here: http://www.zoology.ubc.ca/person/petermann