Empirical assessments of small-scale ecosystem service flows in rural mosaic landscapes in the Ethiopian highlands

Abstract

Human activities have rapidly altered natural ecosystems worldwide, resulting in fragmented ecosystems that are either culturally or formally protected. These ecosystem patches can be critical for ecosystem services (ES) that support human well-being. In the Ethiopian highlands, the remaining church forests and wetlands have a unique conservation status and are part of the global priority areas for biodiversity conservation. ES flows from these ecosystems to surrounding benefiting areas lack local-scale field evidence data and are not well-understood. Here, we empirically quantify the distance-dependent flows for four ES: grass biomass, microclimate regulation, crop pollination, and soil erosion retention since they exhibit considerable variation in spatial scales and processes of ES flows. The effect of spatial distance on each ES benefit flow was analysed using spatially explicit empirical models. The key findings are as follows: (1) The benefit of ES varies significantly with distance to the source ecosystems. (2) ES supply is determined by the extent (fragmentation) and condition of ecosystems, together with ecosystem type. (3) The quantity and number of ES provided decreases with distance from the source, and beneficiaries up to 3 km of the source only receive one type of ES (grass biomass). Approximately 80 % of the benefiting areas are within a radius of 200 m from forests and wetlands. Bundles of multiple ES types are received at the frontiers of service-providing ecosystems, where number of benefits are compared at particular locations from the source point. The investigated ecosystems (440 km²) provided benefits to 8,770 km² for the four types of ES. Our findings imply that non-linear effects of key ecosystem variables need to be considered when mapping the distance-dependent ES flows. This study helps to understand the spatial connectivity between ecosystems and beneficiaries in the human-nature interdependency, which is useful for developing different strategies for ES conservation.