Seasonal and daily climate variation have opposite effects on species elevational range size

Abstract

Variability for a day or a season Species that experience larger seasonal climatic fluctuations are likely to be more physiologically flexible and thus likely to occur across a wider elevational range. Daily changes in temperature are also common but have rarely been considered. Chan et al. used a global data set of vertebrates to look at how these two different sets of variation affect a species' elevational distribution (see the Perspective by Perez et al. ). Unexpectedly, larger daily fluctuations were associated with smaller elevational distributions. Thus, specialists are favored where daily fluctuations are dominant, whereas generalists are favored where seasonal fluctuations are the main climate influence. Science , this issue p. 1437 ; see also p. 1392