Erratum to: Popul Ecol (2009) 51:65–81 DOI 10.1007/s10144-008-0113-5

In the original publication of this article, Eqs. 3, 5 and the text after Eq. 6 of the Electronic Supplementary Material were incorrect. The correct version of the equations and text are given in the link below.

Also please note that the corresponding author's e-mail address has been updated as given in the affiliation.