Conservation value of linear woody remnants for two forest carnivores in a Mediterranean agricultural landscape.
The loss of biodiversity caused by agricultural expansion can be countered by adopting wildlife-friendly farming strategies and by expanding the network of nature reserves. The potential benefits of agricultural extensification, represented in Europe by agri-environmental schemes, still remain unclear. In particular, the effectiveness of preserving linear woody vegetation to retain forest carnivores in farmland has received limited attention. We document the value of hedgerows and narrow strips of riparian forest for the Egyptian mongoose Herpestes ichneumon and the common genet Genetta genetta. In an agricultural mosaic of southern Spain containing 4.7% of woody vegetation, we tested hypotheses about the role of linear elements and three farmland types differing in the amount, quality and structure of woody cover. We analysed the influence of linear elements on the placement and utilization of home ranges by combining compositional analysis and numerical methods. Mongooses and genets strongly selected linear woody vegetation. All types of farmland, including open fields, dehesa (savanna-like pastureland or arable land rich in oak trees Quercus ilex and Q. suber) and olive Olea europaea groves, were avoided, suggesting that both species strictly depend upon native woody cover. Most individuals made regular use of hedgerows and some individuals used hedgerows as the only source of woody cover in their home ranges. The distribution of home ranges suggested that individuals made up a continuous, rather than discrete, population in a spatially structured habitat. An evenly distributed hedgerow network across the intervening agricultural matrix could prevent population fragmentation. Synthesis and applications. A suitable network of linear cover allows some forest carnivores to survive in agricultural landscapes containing a low proportion (<10%) of native woody vegetation. Length (>0.5 km), width (4-10 m), quality (continuous native shrubs, scattered native trees, low levels of human disturbance), density (10-50 m ha-1) and a regular distribution of linear features are key elements in the conservation or restoration of agricultural landscapes where the preservation of small forest carnivores is an objective.