The flora and structure of farmland hedges and hedgebanks near to pheasant release pens compared with other hedges.

Abstract

On farms where shooting takes place, hedgerows leading from woodlands with release pens are often used by pheasants as corridors for accessing game crops. We compared shrub and ground flora structure and species composition in hedges near to and away from release sites with a wide range of release sizes, at 109 game estates in four regions in England in 2002 and 2003. There was more bare ground, fewer stable perennial plant species, more weeds and fewer tree and shrub seedlings in hedges near to release sites compared to our controls, sometimes only when the nearby release exceeded a certain threshold. Alongside hedges there were more weeds on hedgebanks near to release sites, and depending on hedge size, fewer stable perennial species or fewer tree and shrub seedling species. While the woody structure of the hedge itself was not substantially different, shrub leafiness within hedges at 10-20 cm off the ground was reduced in all except very short hedges near to releases. We argue that the differences we observed were due to the presence of pheasants in those hedges during the late summer and autumn following release and not to pen siting or game management factors. We hypothesize that where larger accumulations of pheasants occur in hedges, the changes to ground flora species composition we observed were due to increased soil fertility and soil disturbance. The effects on mature shrub leafiness and woody seedlings were probably caused by direct pecking. Our study involved many sites and some of the effects identified were subtle. Our data on release size enables us to suggest how to minimise these effects where this is considered important, for example where hedgerows are recognized as particularly valuable or vulnerable.