Spatial assessment of ecosystem service trade-offs and synergies in Zimbabwe

Abstract

As the human population continues to increase, ecosystem services (ES) are increasingly under pressure to support livelihoods and economies. This pressure leads to spatial trade-offs among ES in multi-functional landscapes. Characterising ES trade-offs and synergies is critical for sustainable management of ecosystems. This study therefore sought to quantify the spatial structure of ES, as well as assess and map trade-offs and synergies that exist among six ES at national scale in Zimbabwe. Pair-wise relationships between ES were assessed using Pearson’s product moment correlation test. Principal Component Analysis and the K-means cluster analysis were used to detect trade-offs and synergies among ES. The results show that surface water supply and carbon sequestration were positively correlated (r = 0.52). This implies a synergy. By contrast, forage provision was negatively correlated with carbon sequestration and surface water supply (r = -0.38 and -0.51, respectively). A weak but significant correlation was also observed between cattle density and soil conservation. The study for the first time demonstrates the existence of ES trade-offs and synergies throughout Zimbabwe based on six key ES indicators – net primary productivity, surface water supply, cattle density, soil carbon, soil conservation and grazing capacity.