These species are all at risk of extinction. Species with “slow” life-h

Andy Purvis of Imperial College and his colleagues have been leaders in research to understand how the biology of different species interacts with human-mediated changes to cause increased extinction risks. In a recent paper (Purvis et al. 2000), they summarize and test eight hypotheses gathered from the literature. Here we will focus on one of these. As we have seen throughout this chapter, there are a variety of trade-offs associated with reproduction, and many life-history traits appear to be able to be classified into groupings, representing different strategies (this will be explored more fully later in the chapter). One of the initial hypotheses about extinction risk has been that species that have “slow” life histories will be more at risk than those with “fast” life histories. What do we mean by a slow life history? We mean species that have slow growth rates, reach sexual maturity only late in life, breed infrequently and in small numbers, and similar life-history traits. Purvis and colleagues tested this hypothesis by collecting these life-history traits from previously published studies for Carnivora and Primate mammals. Measures of extinction risk were also collected from the literature, specifically the International Union for the Conservation of Nature and Natural Resources Red List.