AVIS-IBIS

Birds of Indian Subcontinent

The effects of habitat structure on predation risk of birds in agricultural landscapes

Publication Type:Journal Article
Year of Publication:2004
Authors:Whittingham, MJ, Evans, KL
Journal:Ibis
Volume:146
Date Published:2004
ISBN Number:1474-919X
Keywords:Charadriidae, Sturnidae, Sturnus, Sturnus vulgaris, Tyto, Tyto alba, Tytonidae, Vanellus, Vanellus vanellus
Abstract:It has been suggested that increased predation rates may rival habitat alteration as a causal agent in farmland bird population declines. Such a view may be over-simplistic, however, as changes in habitat structure may influence habitat selection and foraging efficiency through their influence on perceived and actual predation risk. We review evidence from the literature on the effects of habitat structure on predation risk of foraging and nesting birds and apply these principles to investigate the likely effects on the 20 species that comprise the UK Government's ‘Farmland Bird Index’. Shorter vegetation is likely to enhance foraging efficiency and reduce predation risk (when ground foraging) for 15 of the 20 species. However, within grassland systems longer vegetation is known to enhance food supplies (e.g. Tipulid larvae and voles) of several farmland bird species and so mosaics of short and long vegetation may provide the optimum conditions for most species (e.g. Lapwing Vanellus vanellus, Starling Sturnus vulgaris, Barn Owl Tyto alba). Agricultural intensification has encouraged uniform dense swards, thus reducing habitat diversity, and agri-environment schemes that provide heterogeneous sward structure may thus facilitate farmland bird conservation. Intensification has also resulted in less dense hedgerows; although a reversal of this trend may improve foraging efficiency for many species, it may be detrimental to a smaller number of species that prefer shorter, less dense hedges for nesting. Before these tentative conclusions can be confirmed, more research is required that considers how the effects of habitat structure on individuals is likely to translate into population-level impacts.
URL:http://dx.doi.org/10.1111/j.1474-919X.2004.00370.x
Short Title:Ibis
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith