Abstract: In many species with continuous growth,
body size is an important driver of life-history tactics and its
relative importance is thought to reflect the spatio-temporal
variability of selective pressures. We developed a deterministic
size-dependent integral projection model (IPM) for three insular
neighbouring lizard populations with contrasting adult body sizes to
investigate how size-related selective pressures can influence lizard
life-history tactics.
For each population, we broke down differences in
population growth rates into contributions from size-dependent body
growth, survival, and fecundity. A life table response experiment (LTRE)
was used to compare the population dynamics of the three populations
and quantify the contributions of intrinsic demographic coefficients of
each population to the population growth rate (λ). Perturbation analyses
revealed that the largest adults contributed the most to the population
growth rate, but this was not true in the population with the smallest
adults and size-independent fertility. Although we were not able to
identify a single factor responsible for this difference, the
combination of the demographic model on a continuous trait coupled with a
life table response experiment analysis revealed how sister populations
of the same species follow different life strategies and showed
different compensatory mechanisms among survival, individual body growth
and fertility.Our results indicate that body size can play a
contrasting role even in closely related and closely spaced populations.
A press note (in Spanish) here
Photo; G. Tavecchia |
A press note (in Spanish) here
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