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Advisor(s)
Abstract(s)
Predation is increasingly pointed out as one of the factors contributing to population declines of groundnesting
farmland birds, though it remains poorly understood how ongoing transformations of
agricultural landscapes affect predator assemblages. This study addressed this issue, estimating the
contribution of landscape composition and configuration to spatial variation in species richness and
abundances of mammalian carnivores across a gradient of agricultural intensification in southern
Portugal. The carnivore assemblage was diverse (10 species), but it was largely dominated by just three
widespread and abundant species of generalist predators: domestic dog (Canis familiaris), red fox (Vulpes
vulpes) and Egyptian mongoose (Herpestes ichneumon). The number of domestic carnivore species and
the abundance of cats (Felis catus) increased along with farmland occupation by human dwellings,
whereas dogs were not responsive to landscape variables. The species richness of wild carnivores was
highest in landscapes with a patchwork of arable fields and semi-natural habitats such as forests and
shrubland, though it was also high in irrigated landscapes with dense networks of irrigation channels
and tree lines bordering agricultural fields. Irrigation was also positively associated with the abundance
of otters (Lutra lutra) and mongooses. Cats, foxes, badgers (Meles meles), and total and wild carnivore
abundances, were positively affected by increasing cover by eucalyptus and pine forest plantations. In
general, results suggest that the highest diversity and abundance of carnivores in Mediterranean
farmlandmay occur inmosaic landscapes with small agricultural fields, high cover by woody vegetation
patches and corridors, and many human dwellings. Preventing scrub encroachment and afforestation
may thus be necessary to maintain a low predation risk in open farmland habitats, which are often
inhabited by ground-nesting birds of high conservation concern. Conversely, keeping shrubland and
forest patches within farmed landscapes may be essential where carnivore persistence is a relevant
conservation goal
Description
Keywords
agricultural intensification arable habitats conservation land abandonment irrigation multimodel inference predation risk
Pedagogical Context
Citation
"Agriculture, Ecosystems and Environment". ISSN 0167-8809. 132 (2009) 57-65
Publisher
Elsevier