NSF LTREB (2018-2023)
NSF LTREB (2013-2018)
NSF DDIG – John Benning (2017-2018)
NSF Evolutionary Processes (2005-2010)

A long-standing problem in biology is determining the factors that limit the geographic distribution of organisms. Traditionally, this line of work has involved a strictly ecological perspective where researchers determine the abiotic and biotic factors that limit population growth at range boundaries. However, these proximate explanations fail to explain why populations have not adapted to novel conditions beyond their range boundaries, and thus why species’ often have stable range limits. Despite extensive theoretical work, we currently lack comprehensive empirical investigations that can distinguish the possible ultimate causes of the limits to species’ geographic ranges. For example, do species fail to adapt to conditions outside their contemporary distribution because they (1) lack genetic variation in ecologically-important traits or (2) because migration of maladapted genotypes from geographically central populations prevents adaptation to range edge environments?


In collaboration with Monica Geber (Cornell), Vince Eckhart (Grinnell College), and Bill Morris (Duke) we are examining the ecological and evolutionary factors setting limits on the geographic range of the annual plant, Clarkia xantiana. Our work integrates detailed studies of: (1) abiotic and biotic environment, (2) population demography, (3) ecological genetics, and (4) molecular population genetics. Our multi-disciplinary approach seeks to distinguish among environment-dependent and environment-independent causes of range limits, and the potential genetic constraints on adaptation at range limits.



Related Publications

Benning, J.W., M.A. Geber, V.M. Eckhart, and D.A. Moeller. Biotic interactions limit the geographic range of an annual plant: herbivory and phenology mediate fitness beyond a range margin. in revision.

Bolin, L.G., J.W. Benning, and D.A. Moeller. 2018. Mycorrhizal interactions do not influence plant-herbivore interactions in populations of Clarkia xantiana ssp. xantiana spanning from center to margin of the geographic range. Ecology & Evolution. doi:10.1002/ece3.4523

Pironen, S., J. Villellas, W. Thuiller, V.M. Eckhart, M.A. Geber, D.A. Moeller, and M.B. García. 2018. The “Hutchinsonian niche” as an assemblage of demographic niches: implications for species geographic ranges. Ecography. 41:1103-1113

Gould, B., D.A. Moeller, V.M. Eckhart, P. Tiffin, & M.A. Geber. 2014. Local adaptation and range boundary formation in response to complex environmental gradients across the geographic range of Clarkia xantiana ssp. xantiana. Journal of Ecology 102:95-107.

Moeller, D.A., M.A. Geber, V.M. Eckhart, & P. Tiffin. 2012. Reduced pollinator service and elevated pollen limitation at the geographic range limit of an annual plant. Ecology 93:1036-1048.

Moeller, D.A., M.A. Geber, & P. Tiffin. 2011. Population genetics and the evolution of geographic range limits in an annual plant. American Naturalist 178:S44-S61.

Eckhart, V.M., M.A. Geber, W.F. Morris, E.S. Fabio, P. Tiffin, & D.A. Moeller. 2011. The geography of demography: Long-term demographic studies and species distribution models reveal a species border limited by adaptation. American Naturalist 178:S26-S43.

Eckhart, V.M., I. Singh, A.M. Louthan, A.J. Keledjian, A. Chu, D.A. Moeller, & M.A. Geber. 2010. Plant-soil water relations and the species border of Clarkia xantiana ssp. xantiana (Onagraceae). International Journal of Plant Sciences 171: 749-760.