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Research Themes

Latitudinal gradients in species richness

Although it is not the main focus of my research, I am interested in documenting and understanding mechanisms for latitudinal patterns of range size and species diversity. As such, I examined the effect of scale on patterns of species diversity with latitude (Lyons and Willig, 1999, 2002). I am also interested in latitudinal patterns of range size. My particular contribution consisted of pointing out flaws in existing techniques, designing an alternative statistical test, and applying it to patterns for bats and marsupials (Lyons and Willig, 1997). In addition, I helped develop a theoretical mathematical model predicting the number of species expected at each latitude based on the bounded nature of land masses, also known as the mid-domain effect (Willig and Lyons, 1998). My collaboration with Michael Willig is on going as we continue to explore the implications and limitations of the mid-domain effect.


S. K. Lyons and M. R. Willig. 1997. Latitudinal patterns of range size: methodological concerns and empirical evaluations for New World Bats and Marsupials. Oikos 79:568-580.

S. K. Lyons and M. R. Willig. 1999. A hemispheric assessment of scale-dependence in latitudinal gradients of species richness. Ecology. 80(8): 2483-2491. (Special Feature)

S. K. Lyons and M. R. Willig. 2002. Species richness, latitude, and scale-sensitivity. Ecology 83: 47-58.

M. R. Willig and S. K. Lyons. 1998. An analytical model of latitudinal gradients of species richness with an empirical test for Marsupials and Bats in the New World. Oikos 80:93-98.

Species and community level responses to climate change

Macroecological patterns across space and time

Macroevolutionary dynamics of mammals

Biases in the mammalian fossil record

Extinction risk


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