Abstract
Livestock grazing is a major driver of ecosystem
change and has been associated with significant
declines in various bird species in Britain and
worldwide. However, there is little experimental
evidence to show how grazing affects bird populations.
We manipulated livestock densities in a
replicated field experiment and found that
mixed sheep and cattle grazing, at low intensity,
improved the breeding abundance of a common
upland passerine, the meadow pipit Anthus
pratensis, after two years. Plots stocked with
sheep alone (at high or low density) or not stocked
at all held fewer pipit territories. Despite a yearon-
year decline in pairs of meadow pipits in
intensively grazed plots, we found no effect of
sheep number on breeding abundance. Our
results support the hypothesis that mixed
species of herbivores generate greater heterogeneity
in vegetation structure, which modifies
prey availability, resulting in a greater abundance
of birds. The results of our study should
inform the management of grassland areas and
enhance the abundance of some bird species,
particularly in areas that have seen significant
shifts from mixed livestock grazing to grazing
dominated by single species of animals.
Year
2006
Category
Refereed journal