Dataset Information

Climate tolerance and interspecific variation in geographic range size.

ABSTRACT: The fact that climate influences the continental-scale distributions of species is one of the central tenets of ecology and biogeography. Equally elemental is that species exhibit enormous variation in geographic range size, with most occupying comparatively small areas. The degree to which climate can account for this variation remains unclear. Here, I test three alternative climate-based hypotheses for variation in range size using a large sample of tree and shrub species native to North America north of Mexico. I show that the lowest value of January average daily minimum temperature encompassed by a species' geographic range (T(MIN)), representing the 'climate extremes hypothesis', explains almost 80% of the variation in range size. Hypotheses based on seasonality and climate optima find substantially less support. The relationship between range size and T(MIN) does not change across the breadth of latitudes examined, and is general for conifers and hardwoods, and growth form (tree versus shrub). Differential freezing resistance gains support as the mechanism underlying interspecific variation in range size: using 35 species for which data were available, both T(MIN) and range size are shown to be strongly correlated with measures of freezing resistance.

SUBMITTER: Pither J

PROVIDER: S-EPMC1691271 | biostudies-literature | 2003 Mar

REPOSITORIES: biostudies-literature

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Climate tolerance and interspecific variation in geographic range size.

Pither Jason J

Proceedings. Biological sciences 20030301 1514

The fact that climate influences the continental-scale distributions of species is one of the central tenets of ecology and biogeography. Equally elemental is that species exhibit enormous variation in geographic range size, with most occupying comparatively small areas. The degree to which climate can account for this variation remains unclear. Here, I test three alternative climate-based hypotheses for variation in range size using a large sample of tree and shrub species native to North Ameri ...[more]

PMID: 12641901

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Project description:Offspring size is a key functional trait that can affect subsequent life history stages; in many species, it exhibits both local adaptation and phenotypic plasticity. Variation among populations in offspring size may be explained by various factors, including local climatic conditions. However, geographic variation in climate may be partitioned into long-term and interannual sources of variation, which may differ in their effects on population mean offspring size. To assess environmental correlates of offspring size, we evaluated geographic variation in seed mass among 88 populations representing 6 species of Streptanthus (Brassicaceae) distributed across a broad climatic gradient in California. We examined the effects of temperature-mediated growing season length and precipitation on population mean seed mass to determine whether it is best explained by (1) long-term mean climatic conditions; (2) interannual climate anomalies (i.e., deviations in climate from long-term means) during the year of seed development, or (3) interactions between climate variables. Both long-term mean climate and climate anomalies in the year of collection were associated with population mean seed mass, but their effects differed in direction and magnitude. Relatively large seeds were produced at chronically wet sites but also during drier-than-average years. This contrast indicates that these associations may be generated by different mechanisms (i.e., adaptive evolution vs. phenotypic plasticity) and may be evidence of countergradient plasticity in seed mass. In addition, populations occurring in locations characterized by relatively long growing seasons produced comparatively large seeds, particularly among chronically dry sites. This study highlights the need to consider that the responses of seed mass to long-term versus recent climatic conditions may differ and that climate variables may interact to predict seed mass. Such considerations are especially important when using these patterns to forecast the long- and short-term responses of seed mass to climate change. The results presented here also contribute to our broader understanding of how climate drives long-term (e.g., local adaptation) and short-term (e.g., phenotypic plasticity) variation in functional traits, such as offspring size across landscapes.

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Dataset Information

Climate tolerance and interspecific variation in geographic range size.

Publications

Climate tolerance and interspecific variation in geographic range size.

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