ORIGINAL INVESTIGATION Is polecat (Mustela putorius) diet affected by ‘‘mediterraneity’’? Maria J. Santos à , Hugo M. Matos, Carla Baltazar, Clara Grilo, Margarida Santos-Reis Universidade de Lisboa, Faculdade de Cieˆncias, Centro de Biologia Ambiental and Departamento de Biologia Animal, Campo Grande, Ed. C2, 1749-016 Lisboa, Portugal Received 14 April 2008; accepted 27 August 2009 Abstract Carnivores in Mediterranean ecosystems respond to the inherent heterogeneity of these systems by tracking the spatial and temporal availability of food resources. This feeding strategy, however, has been associated primarily with generalist carnivores and little is known for specialist species such as the European polecat. We collected polecat scat to determine the diet of this species, how it matches the seasonal availability of food resources, and how it is affected by population spatial structure and anthropogenic disturbance. Polecats were present in only 34% of the surveyed area and were clumped into three main population nuclei. Despite the spatial segregation of the populations, they had no significant differences in food items consumed. Polecats mostly fed on mammals (percentage of occurrence (P.O.)=43%) and arthropods (P.O.=49%). Biomass intake was also mostly from mammals (percentage of biomass (P.B.)=96%), followed by birds (P.B.=3%), with arthropods contributing less than 1%. Lagomorphs were the most consumed prey (P.O.=25% and P.B.=87%), which is consistent with the marked spatial overlap between scat with high content in lagomorphs and the areas with high wild rabbit availability. These results indicate that polecats are specialists in the consumption of wild rabbits, spatially track the availability of this prey, and may be affected by the decrease in abundance of the prey populations. Future conservation of polecats in Mediterranean regions of southern Portugal may be achieved through the restoration of hunted and diseased wild rabbit populations. & 2009 Deutsche Gesellschaft fu ¨ rSa ¨ ugetierkunde. Published by Elsevier GmbH. All rights reserved. Keywords: European polecat; Wild rabbit; Conservation; Alqueva dam; Guadiana basin Introduction Mediterranean-type ecosystems are a mosaic of landscape patches. This inherent heterogeneity is a result of varying natural disturbance regimes (for example see, Rundel et al. 1998) combined with long- term anthropogenic influence (Blondel 2006). This has resulted in a biotic community with high resilience (Lavorel 1999). The dynamism of these systems, induced by natural fire regimes, deforestation, land conversion and multi-use subsistence agriculture, poses challenges to the wildlife depending on these ecosystems. Mamma- lian carnivores have large home ranges, which makes them greatly affected by habitat heterogeneity and loss. Thus, they are often indicator species and their populations require urgent conservation actions (Singleton et al. 2002). Carnivores are also important regulators of ecosystem function because of their role in controlling prey populations (Terborgh et al. 1999), and have evolved different feeding strategies to match the resource availability within the ecosystem they inhabit. ARTICLE IN PRESS www.elsevier.de/mambio 1616-5047/$ - see front matter & 2009 Deutsche Gesellschaft fu ¨ rSa ¨ ugetierkunde. Published by Elsevier GmbH. All rights reserved. doi:10.1016/j.mambio.2009.08.007 Mamm. biol. 74 (2009) 448–455 à Corresponding author at: University of California, Davis, Depart- ment of Land, Air and Water Resources, One Shields Avenue, Davis 95616 California, USA. Tel.: +1 530 752 5092. E-mail addresses: mjsantos@fc.ul.pt, mjsantos@ucdavis.edu (M.J. Santos).