Edge effects on nest predation in Mediterranean fragmented forests

Edge effects on predation of artificial avian nests were studied in a forest archipelago mixed with agricultural land in Central Spain. Predation rates were lower on farmland than in the forest habitat. There was a trend towards lower predation on the forest edge than in the interior. This edge-core predation gra- dient differed from the usual pattern of nest predation found in other temperate fragmented forests. Predation by rodents was almost completely restricted to the forest habitat. We suggest that in very small fragments, such as those studied here, a 'packing effect' of small specialist forest predators could be the cause of high predation rates throughout the forest.