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In the last decades, ecological theory has changed focus from the assumption of homogeneity to the recognition of heterogeneity as key for understanding the complexity of nature (Wiens 1989, Levin 1992). Yet the role of organisms in altering this spatial structure at different scales is still a field that requires further attention. Huffaker (1958) was one of the first to demonstrate the importance of spatial scale to ecological processes and patterns by conducting a simple experiment with oranges, mites and mite predators. During these experiments, mites could not co-exist with their predator on a single orange, while on a larger scale a network of multiple connected oranges allowed long-term co-existence of predator and prey. With this simple experiment Huffaker showed that ecological processes are influenced by scaledependent patterns and that the scale of observation is important to draw valuable conclusions. Since this work, the concept of scale in ecology received increasing attention in various ecosystems (Wiens 1989, Levin 1992, Solan et al. 2003, Sandel and Smith 2009).

Very closely connected to spatial scale is spatial structure ranging from cells to landscapes, eg the distribution and abundance of organisms within landscapes (Hutchinson 1953, Turner 2005). Forman and Godron (1981) described landscapes as heterogeneous ecological units, where biotic and abiotic interactions occur in a mosaic of patches that change in structure and functioning through time. Since this work, the interactions between spatial structure of the landscape and ecological processes have been the focus of many studies. Also on a much smaller scale …