Impacts of land-use intensity on ecosystems stability
Joana Canelas, Henrique M. Pereira
Abstract
Human appropriation of net primary production (HANPP) is nearly 25% of global potential NPP and above 40% in Europe (Plutzar et al., 2015). Simultaneously, land-use change and intensification are two major threats to biodiversity (Flynn et al., 2009; Pereira et al., 2012). Yet, the relationship between biodiversity and ecosystem's productivity is highly context dependent and the global impacts of land-use intensity, despite its increasing relevance, are still poorly understood. We assess the impacts of land-use intensity (as a component of HANPP) on ecological stability through an ecological network model with two trophic levels. We compare the impacts of harvest intensity and distribution on three metrics of ecosystem's stability, namely asymptotic stability, biomass variability and species persistence (i.e. structural robustness), relating those to the ecosystem's capacity to sustain provisioning services (e.g. total yields). We found that increasing land-use intensity drives a decrease in all metrics of ecological stability, also affecting the ecosystem's productivity in a non-monotonous way. Moreover, these impacts’ severity depend primarily on the community's richness and the harvest's distribution. This study advances knowledge on the ecological impacts of land-use intensity, revealing how it affects distinct metrics of ecological stability, how these relate to the sustenance of ecosystem processes and the role of disturbances magnitude and distribution. Our results suggest that more biodiverse agricultural systems and homogeneous harvest distributions (e.g. through polycultures) could both reduce land-use intensity impacts and increase the total yields obtained, while reducing yields uncertainty.