Nationwide trophic cascades: changes in avian community structure driven by ungulates.
In recent decades, many ungulate populations have changed dramatically in abundance, resulting in cascading effects across ecosystems. However, studies of such effects are often limited in their spatial and temporal scope. Here, we contrast multi-species composite population trends of deer-sensitive and deer-tolerant woodland birds at a national scale, across Britain. We highlight the divergent fates of these two groups between 1994 and 2011, and show a striking association between the calculated divergence and a composite population trend of woodland deer. Our results demonstrate the link between changes in deer populations and changes in bird communities. In a period when composite population trends for deer increased by 46%, the community population trend across deer-sensitive birds (those dependent on understory vegetation) declined much more than the community trend for deer-tolerant birds. Our findings suggest that ongoing changes in the populations of herbivorous ungulates in many countries worldwide may help explain patterns of community restructuring at other trophic levels. Ungulate impacts on other taxa may require more consideration by conservation practitioners than they currently receive.
School of Biological and Biomedical Sciences, Durham University, South Road, Durham, DH1 3LE.|Department of Biology, University of York, York, YO10 5DD.
Georgina
G
Palmer
School of Biological and Biomedical Sciences, Durham University, South Road, Durham, DH1 3LE.
Philip A
PA
Stephens
National Wildlife Management Centre, Animal and Plant Health Agency, York YO41 1LZ.|School of Biological, Biomedical and Environmental Science, University of Hull, Cottingham Road, Hull, HU6 7RX.
Alastair I
AI
Ward
School of Biological and Biomedical Sciences, Durham University, South Road, Durham, DH1 3LE.
Stephen G
SG
Willis
D000818:Animals; D001717:Birds; D003670:Deer; D065928:Forests; D060434:Herbivory; D011157:Population Dynamics; D006113:United Kingdom