Diversity components of impending primate extinctions

Abstract

Many extant species are at risk to go extinct. This impending loss of species is likely to cause changes in future ecosystem functions. Ecological components of diversity, such as dietary or habitat specializations, can be used to estimate the impact of extinctions on ecosystem functions. As an approach to estimate the impact of future extinctions, we tested interdependency between ecological and taxonomic change based on current predictions of extinction rates in primates. We analyzed the ecological characteristics of extant primate faunas having species in various categories of endangerment of extinction and forecasted the future primate faunas as if they were paleontological faunas. Diversity of future ecosystems can be predicted to decline because present-day extinction rates of organisms may rival those in the fossil record and many living species are at risk to go extinct in the near future (1, 2). In extant ecosystems, ecological attributes of species can influence ecosystem processes more than number of species (species richness) per se (3-5). For example, loss of all of the species that perform a specific ecological function, such as seed dispersal, may limit long-term ecosystem competence. Therefore, full appraisal of the impact of loss in biological diversity requires the inclusion of ecological components of diversity.To simulate large time scale (i.e., paleontological or macroevolutionary) diversity losses using living faunas, in this paper we introduce an approach. We analyzed the ecological characteristics of extant faunas having species in various categories of endangerment of extinction and forecasted ecological integrity of faunas in the future, assuming extinctions proceed according to current rankings of endangerment. Predicting future faunas allows us to circumvent the problem that living species represent only one geological instant in the history of earth and fossil record-like changes in diversity cannot be directly observed. On the other hand, the use of extant fauna avoids the problem that fossils provide limited information on the ecological components of diversity, such as dietary or habitat specializations. These factors can be known from extinct species only indirectly via morphology (6-10).Of mammals, the order Primates has the highest proportion of endangered species (11,12), mainly because of humancaused habitat destruction and hunting (11)(12)(13)(14)(15)(16). Ecology of primate species is extensively studied and primates play a key role in many ecosystem processes (17)(18)(19)(20). First, we analyzed ecological richness (number of ecological types such as dietary specializations) and ecological composition of extant primate faunas in four geographical regions. Ecological composition is conceptually different from richness and characterizes the resource use (e.g., diet and habitat) of faunas. This allows measuring of ecological dissimilarity and range of adaptations. Then, using endangerment categories, we made projections of the integrity of extant primate faunas in the...

Predicting how populations decline to extinction

“…We compared this global proxy of species population trend with data collated at a site-level from the population abundance database. habitat breadth narrow habitat breadth suggests specialization and therefore poor ecological adaptability and flexibility; specialists are more susceptible to habitat modification and loss, and thus at an increased risk of extinction; in addition, narrow habitat breadth is associated with a small geographical range, which can put an entire species at risk [15,22,26,27] Predicting population decline B. Collen et al 2579…”

Phylogenetic and functional diversity in large carnivore assemblages

“…Unfortunately, there are still no unified metrics that includes all aspects of biodiversity [10], and the use of PD as a proxy for FD is not unequivocally supported [2,11,12]. Because it may not be possible to simultaneously optimize conservation of all aspects of biodiversity, it is important to recognize the value of each component.…”

Phylogenetic diversity does not capture body size variation at risk in the world's mammals

“…Conservation prioritization on the basis of species numbers alone does not capture all aspects of evolutionary history, phylogenetic diversity (PD) or ecosystem roles (Vane-Wright et al 1991;Millennium Ecosystem Assessment 2005). While it is clear that some species are more ecologically important because ecosystem processes depend on their biological traits, the magnitude of functional-trait loss may not be easily predicted from either species or PD loss (Jernvall & Wright 1998;Gross & Cardinale 2005;Hooper et al 2005). Our study therefore aims to map the global loss of evolutionary history as well as changes of the variance in a key species trait, body size, if all currently threatened mammalian species were to go extinct.…”

“…Evolutionary history or PD is sometimes used as a proxy for FD (Faith 1992;Forest et al 2007), because it is an indirect measure of phenotypic diversity if traits evolve along the branches of phylogeny. However, PD and FD of a community can be uncorrelated, so PD loss cannot always reliably predict FD loss (Jernvall & Wright 1998;Hooper et al 2005). Our aim was to compare possible losses of mammalian diversity using three diversity measures: species richness, PD and BMV, where both PD and BMV can be seen as tentative measures of mammalian FD.…”