Skip to main content
U.S. flag

An official website of the United States government

Agricultural management affects evolutionary processes in a migratory songbird

January 1, 2008

Hay harvests have detrimental ecological effects on breeding songbirds, as harvesting results in nest failure. Importantly, whether harvesting also affects evolutionary processes is not known. We explored how hay harvest affected social and genetic mating patterns, and thus, the overall opportunity for sexual selection and evolutionary processes for a ground-nesting songbird, the Savannah sparrow (Passerculus sandwichensis). On an unharvested field, 55% of females were in polygynous associations, and social polygyny was associated with greater rates of extra-pair paternity (EPP). In this treatment, synchrony explained variation in EPP rates, as broods by more synchronous females had more EPP than broods by asynchronous females. In contrast, on a harvested field, simultaneous nest failure caused by haying dramatically decreased the overall incidence of EPP by increasing the occurrence of social monogamy and, apparently, the ability of polygynous males to maintain paternity in their own nests. Despite increased social and genetic monogamy, these haying-mediated changes in mating systems resulted in greater than twofold increase in the opportunity for sexual selection. This effect arose, in part, from a 30% increase in the variance associated with within-pair fertilization success, relative to the unharvested field. This effect was caused by a notable increase (+110%) in variance associated with the quality of social mates following simultaneous nest failure. Because up to 40% of regional habitat is harvested by early June, these data may demonstrate a strong population-level effect on mating systems, sexual selection, and consequently, evolutionary processes. ?? 2008 The Authors.

Publication Year 2008
Title Agricultural management affects evolutionary processes in a migratory songbird
DOI 10.1111/j.1365-294X.2008.03695.x
Authors N.G. Perlut, C. R. Freeman-Gallant, A.M. Strong, T.M. Donovan, C.W. Kilpatrick, N.J. Zalik
Publication Type Article
Publication Subtype Journal Article
Series Title Molecular Ecology
Index ID 70031998
Record Source USGS Publications Warehouse