Linear habitats as plant ecological refuges in fragmented agricultural landscapes: a method for condition assessment

In Mediterranean Europe, both the intensification and abandonment of traditional cultural practices are major factors leading to the degradation and loss of natural and semi-natural elements in agricultural landscapes. These non-crop habitats can serve as ecological refuges, which integrate the goals of biodiversity conservation and sustainable food production in agroecoystems. Therefore, they need to be conserved or restored to enhance the resilience and resistance of agricultural systems against biodiversity loss and socio-ecological changes. Notably, linear landscape elements (LE) are high-biodiversity features that must be increased in fragmented agricultural lands to facilitate species movement and provide a variety of ecosystem services. However, in the context of environmental accounting procedures, there is still a need for a comprehensive methodology to evaluate the condition of LE and of the hosting agroecosystems. This research therefore aims to (i) propose a method for a thorough assessment of LE conditions, with a focus on their capacity to support biodiversity, (ii) investigate the potential influence of external factors on LE conditions, such as proximity to protected habitats and the governance framework, and (iii) identify useful parameters to guide ecological restoration actions for LE. Using various structural, compositional, and landscape indicators, the proposed assessment method was tested in eight administrative units across two Mediterranean European countries. In the study sites, favorable LE conditions were closely linked to contiguity to protected habitats, exhibiting marked structural continuity, a prevalence of trees, active dynamics, and high-quality surrounding landscape mosaics. The potential applications of these findings have been explored in the context of ecosystem accounting and ecological restoration processes.