Population regulation of territorial species and the complexity of the regulatory process.

Population regulation of territorial species: both site dependence and interference mechanisms matter

Marie Nevoux1,Olivier Gimenez,Debora Arlt, Malcolm Nicoll, Carl Jones and Ken Norris

Published online before print December 15, 2010, doi: 10.1098/rspb.2010.2352 Proc. R. Soc. B 22 July 2011 vol. 278 no. 1715 2173-2181

I read this paper the other day and found it very interesting.

It is assumed that spatial patterns of site occupancy are driven by habitat heterogeneity and this has a bearing in shaping population dynamics through a site-dependent regulatory mechanism. The authors say most studies have only focused on a single vital rate (reproduction), and little is known about how space effectively contributes to the regulation of population dynamics. They investigated the underlying mechanisms driving density-dependent processes in vital rates in a Mauritius kestrel population where almost every individual was monitored.

Different mechanisms acted on different vital rates. The breeding success was regulated by site dependence (differential use of space) and juvenile survival by interference (density-dependent competition for resources).

Although territorial species are frequently assumed to be regulated through site dependence, the researchers show that interference was the key regulatory mechanism in this population.  The integrated approach demonstrated that the presence of spatial processes regarding one trait does not mean that they necessarily play an important role in regulating population growth, and demonstrates the complexity of the regulatory process.