The current human dominance and the concomitant anthropogenically induced global environmental change cause rapid transitions from natural to novel ecosystems. These ecologically novel systems consist of non-indigenous and non-coevolved species and are particularly frequent on islands, in anthropogenically transformed agricultural landscapes, and in urban areas. Novel ecosystems are subject to novel stressors and characterized by non-analogous biotic assemblages.

We aimed to understand the processes leading to the rapid transition from natural to novel communities and ecosystems, i.e. the direction, speed and persistence of change with increasing levels of ecological novelty. We thereby particularly focus on transition zones from agricultural or other non-urban to urban systems and on gradients of invasion by non-native species. We were looking at urbanization as a broad anthropogenic novel stressor that emcompasses more specific stressors such as human population density, sealing, heavy metals or the urban heat-island effect. We wanted to

• synthesize the field of ecological novelty using a network-based approach;
• develop and apply advanced multidimensional measures of biotic and abiotic novelty;
• investigate how ecological novelty affects above-belowground interactions, and how these affect the functioning of urban communities;
• quantify the relative contribution of genetic vs. epigenetic differences in explaining trait and fitness variations among populations in urban communities;
• explore consequences of ecological novelty for human health; and
• investigate how food-web dynamics across ecosystem boundaries are affected by increasing levels of ecological novelty.