Spatial distribution models in a frugivorous carnivore , the stone marten ( Martes foina ) : is the fl eshy - fruit availability a useful predictor ?

Fleshy-fruit availability is rarely used as a predictor in stone marten ( Martes foina ) habitat models, despite its frugivorous carnivore diet. Data on stone marten occurrence, habitat structure and fl eshy-fruit species abundance was collected along 2 km long survey routes within 2 x 2 km sample plots (n = 30). Two different spatial scales were considered: 1) the entire survey route; and 2) 200 m segments within each 2 km survey route. Data analyses included Poisson General Linear Models (GLM) and Generalized Linear Mixed Models (GLMM) for the fi rst and second approaches, respectively. Strawberry tree ( Arbutus unedo ) availability was signifi cantly and positively correlated to stone marten occurrence at both spatial scales, particularly for the large-scale model. At the larger scale, a lower correlation to the traditional habitat structure variables was observed. Tree cover was the most important variable in the small-scale model, but strawberry tree availability was also an important predictor. Stone marten abundance was low in areas of high tree cover and absence of strawberry trees; emphasising the prominent role of strawberry trees per se in the abundance of stone martens. Our results indicated that including fi ne, fi eld-derived estimates of key food resources for species can increase the utility of habitat models. © Koninklijke Brill NV, Leiden, 2010.