Why is adaptation prevented at ecological margins? New insights from individual-based simulations Journal Article


Author(s): Bridle, Jon R; Polechová, Jitka; Kawata, Masakado; Butlin, Roger K
Article Title: Why is adaptation prevented at ecological margins? New insights from individual-based simulations
Affiliation IST Austria
Abstract: All species are restricted in their distribution. Currently, ecological models can only explain such limits if patches vary in quality, leading to asymmetrical dispersal, or if genetic variation is too low at the margins for adaptation. However, population genetic models suggest that the increase in genetic variance resulting from dispersal should allow adaptation to almost any ecological gradient. Clearly therefore, these models miss something that prevents evolution in natural populations. We developed an individual-based simulation to explore stochastic effects in these models. At high carrying capacities, our simulations largely agree with deterministic predictions. However, when carrying capacity is low, the population fails to establish for a wide range of parameter values where adaptation was expected from previous models. Stochastic or transient effects appear critical around the boundaries in parameter space between simulation behaviours. Dispersal, gradient steepness, and population density emerge as key factors determining adaptation on an ecological gradient.
Keywords: Population Genetics; Adaptation; dispersal load; ecological margin; habitat patch; individual-based simulation; population ecology
Journal Title: Ecology Letters
Volume: 13
Issue 4
ISSN: 1461-023X
Publisher: Wiley  
Date Published: 2010-04-01
Start Page: 485
End Page: 494
DOI: 10.1111/j.1461-0248.2010.01442.x
Notes: We are very grateful to Nick Barton, Sergey Gavrilets, and Mark Kirkpatrick for discussion of our results, and earlier drafts of this MS. We also thank Robert Holt, and two anonymous referees for very helpful comments on the MS. JB was funded by a Zoological Society of London Postdoctoral Fellowship. JB and RB were both supported in part by funding from NERC and the Japanese Society for the Promotion of Science. MK was supported in part by the Global COE Program ÔCentre for ecosystem management adapting to global changeÕ (J03) of the Ministry of Education, Culture, Sports, Science and Technology of Japan. JP has been supported by EPSRC funded NANIA network, GRT11777 and IST Austria.
Open access: no