Abstract
Understanding the dynamics of small populations is critical to conserve
those species at most risk. Previous work has identified demographic and
environmental factors that can mutually reinforce one-another to drive
populations rapidly to extinction – a process known as the ‘extinction
vortex.’ However, studies investigating robustness to the extinction
vortex in relation to life history and ecological traits have been
lacking. Here, we assemble a database of 55 vertebrate populations
monitored to extirpation and perform three analyses to investigate
whether a key fitness-related phenotypic trait – body size –
influences the rate at which populations succumb to the extinction
vortex. We find evidence that populations of smaller-bodied species
deteriorate at a faster rate, suggesting that intrinsic biological
traits can alter the susceptibility of species to the extinction vortex,
and may serve as a useful feature for prioritizing which populations to
invest conservation effort in.