Evaluating hedgerow implantation with native species in Mediterranean agricultural landscapes: implications for CAP environmental measures—a case study in southern Spain

Abstract

In this study, seventeen hedgerows (4 × 20 m; composed of trees, shrubs and bushes) were established in an experimental agricultural field in southern Spain, combining different planting and management techniques: pre-planting tillage or no-tillage; irrigation or rainfed; use of anti-weed mesh or not, and use of tube shelters or not. The purpose of this study was to provide a technical and economic evaluation of these 17 design proposals for hedgerow implantation under Mediterranean conditions, using native species. Plant survival and growth were measured one year after planting, and the implantation costs of each hedgerow was calculated. Our results showed that a simple combination based on pre-planting tillage, rainfed conditions, and no mulching or tube shelters worked well, resulting in high plant survival rates (around 90%) and growth (0.32 m² yr⁻¹ increased plant cover), with one of the lowest hedgerow implantation costs (€16.5 m⁻¹, for 2024). Deficit irrigation only resulted in a slight increase in plant survival (9.4% on average). Using plastic mulch resulted in higher plant growth but had higher implantation costs and raised concerns about the hazard of plastic contamination. Under our conditions, without herbivory, the use of tube shelters had no significant effect on plant survival and growth. The most basic option, same as above but without tillage, had the lowest hedgerow implantation cost, but a plant survival rate below 50%. However, even using this latter option, the hedgerow implementation cost was higher than the financial support for implementing the biodiversity areas in farmland eco-scheme (which includes hedgerows) under the current CAP in Spain. Therefore, better financial incentives for these eco-schemes are needed to maximize their beneficial impact on agricultural landscapes.