An Evaluation of the Distance at Which Direct Ecological Effects of Released Pheasants Extend Beyond Their Release...

In the UK, large numbers of pheasants (Phasianus colchicus) are released into woodlands annually for recreational hunting. Post-release, they are managed to keep them in areas where they can be shot from October to January. At sites with high pheasant densities, they can negatively impact local flora and fauna through predation, trampling, and altering soil nutrients via defecation. The extent of these effects beyond release pen sites is unclear. This study investigated at what distance from release sites a suite of ecological effects of released gamebirds might be detected. We surveyed along 1 km transects from release pens at 20 shoots in Ancient Semi-Natural Woodlands (ASNW) in England and Wales. We expected higher soil nutrients, fewer characteristic woodland plants, more nitrogen-tolerant species, more damage to dead wood, and fewer woody seedlings near pens, with effects decreasing with distance. We found that pheasant numbers encountered declined with distance and sites closer to pens had fewer seedlings/saplings, lower vascular plant richness and less decayed wood (although this last result may be an artefact of the study design). These effects did not extend beyond 500 m. Contrary to expectations, soil nutrients, bare ground, and ancient woodland indicator species showed no consistent change with distance, and nitrogen-loving species and weeds were more common further from pens. We conclude that, in areas beyond release pens in ASNW in lowland England and Wales, where pheasants are not deliberately enticed, any direct negative effects on plant communities, soil nutrients and ground cover do not extend further than 500 m from the point of release. The current licensing of gamebird releases in England aims to protect designated woodlands by controlling releases occurring within a 500 m buffer around protected areas. Our results suggest that this buffer size appears to be appropriate to contain these effects of released gamebirds.