How does landscape fragmentation affect abiotic ecosystem services and human wellbeing?

Introduction
Fragmentation of landscapes is a dynamic ecological process which is partly anthropogenically driven. Fragmented landscapes are characterised by the occurrence of discontinuities or variations in prevalent or native land cover and habitat properties (Strayer et al., 2003). The transition zones between different ecotopes are influenced by active and passive exchange of matter and energy and have different properties than native forest or plain pasture or agricultural land.
Globally, Haddad et al. (2015) calculated that 20% of forested land was located in a forested transition zone of 100 m (see Schmidt et al., 2017 for a review). In the federal state Brandenburg in Germany it is even 41% (Table 1). Some taxa clearly respond positively or negatively to changes in microclimate in transition zones as does matter cycling (e.g. decomposition and biomass production; Godefroid et al., 2006; Heithecker and Halpern, 2007; Magnago et al., 2015).

Problem
Most of the research concerning transition zones and their effects has been done for diversity and abundance of animals and plants (see Ries et al., 2004). Compared to biotic effects, abiotic effects have rarely been investigated, and if so, these studies are often not comparable (Murcia, 1995). Apart from abiotic factors, transitional zones’ influence on matter cycling, deposition, and water flow are even less understood. Moreover, a big share of studies on abiotic factors took place in Australia and the Tropics; only some studies exist for Europe and America. A reason for these issues might be that continuous and direct measurements are highly cost intensive, a linkage between measured data, remote sensed data and a data base would help to close knowledge gaps.

Approach and methods
First, we measure microclimate in two transition zones in Brandenburg, Germany. Further, litterfall and aboveground biomass, soil carbon and nitrogen stocks and soil microbial activity and diversity were measured in a transect from forest to agricultural field. The goal is to better understand carbon sequestration in forest transition zones compared to forest core matrix. Moreover, the yields of the adjacent agricultural fields are measured to get insights into the extent of reduced yields in transition zones.
Second, we are developing a modelling approach to estimate the effects on several ecosystem services in transition zones on a broader scale (landscape level). This approach shall be applied to existing simulation models to make future predictions on ecosystem services like yields and carbon sequestration by trees in transition zones. The modelled gradients will be compared to another approach where we try to find gradients in fragmented landscapes with remote sensing to achieve the scalability.