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Sceloporus Undulatus: Comparative Life History and Regulation of a Kansas Population
Gary W. Ferguson, Charles H. Bohlen and H. Patrick Woolley
Vol. 61, No. 2 (Apr., 1980), pp. 313-322
Stable URL: http://www.jstor.org/stable/1935190
Page Count: 10
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The demography of a small, isolated population of the lizard, Sceloporus undulatus garmani from eastern Kansas, USA was studied for 5 yr. Growth rates were relatively rapid; age of maturity, relatively low; clutch size was small and decreased in successive clutches of the same females; juvenile survival, while low, was high for the species; adult survival was relatively low. The population size was the most variable yet studied. Winter-spring mortality rates, probably due to predation, were constant regardless of density, but density-dependent mortality operated in at least 1 yr during this period. Summer-fall recruitment was density dependent, probably due to predation on egg-laying females, but flooding and possible temperature-dependent predator susceptibility resulted in instability of the population size. The population is probably below its resource limits most of the time. The comparative demography of this and eight other populations of S. undulatus reported in the literature was summarized. There are three ecological regions to which this species has adapted: eastern woodland, grasslands, and canyonlands. There are both regional and latitudinal differences in suites of correlated traits, but comparative data on ecological pressures are not sufficient to support any single current theory of how these different populations are adapted.
Ecology © 1980 Wiley