The spatial ecology of Ontario’s only lizard, the five-lined skink, reveals a link between habitat selection, abundance, mating systems, and body size

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Joshua Feltham


Reptiles are among the most endangered vertebrates in Canada because their distribution is limited by temperature and it overlaps with our largest human populations. Patterns of habitat selection and distribution reveal information about the interactions and environmental characteristics that are most important for survival. Habitat selection, distribution, and body size of Ontario’s only lizard species, the five-lined skink, at the northern limit of its range provides strong support for three ecological theories that predict range limits, mating systems, and body size. First, at high latitudes, reptiles are limited by the availability of suitable temperatures early in the spring and in the fall. Topography and vegetation cover are the greatest predictors of temperature and therefore, the greatest predictors of the distribution and abundance of five-lined skinks. This supports the concept that abiotic (non-living) factors have the strongest influence on species range limits at high latitudes. Second, uneven distribution of sites with suitable temperatures result in uneven distribution of skinks. Areas with high concentrations of skinks create conditions that favour polygamy, a mating system characterized by both males and females mating with more than one individual in the same season. Third, polygamous mating systems are good predictors of differences in body size between males and females and a predictable pattern of body size variation as latitude increases. Knowledge of the environmental variables that limit species range, abundance, and mating systems provides great insight for the conservation of endangered reptile species at high latitudes.

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