Observing changing ecological diversity in the Anthropocene

www.frontiersinecology.org I derived from a species’ range is central to the science of ecology. Current patterns of species and physiological trait distributions contain important information about plant functional relationships to climate and other environmental controls (Cody and Mooney 1978; Davis 1986; Bonan and Sirois 1992; Kearney and Porter 2009; Rödder et al. 2011). In a foundational paper, Ter Braak and Prentice (1988) wrote, “All species occur in a characteristic, limited range of habitats, and within their range, they tend to be most abundant around their particular environmental optimum”. While this appraisal of the range–niche relationship is too simplistic, ignoring the effects of species interactions (competition, mutualisms, predation, parasitism, and herbivory), distributional information is nonetheless crucial for constructing models that will help us to understand future ecological responses to global climate change. Some modeling paradigms extract information directly from species’ ranges to estimate model parameters, while others rely on distributions to validate models based on mechanistic simulation of reproduction, mobility, and competition. Current rates of climate change equal or exceed the highest rates observed in the recent paleorecord (Loarie et al. 2009), while the impacts of land-use changes and invasive species are unprecedented. Given current rates of environmental change, the information inherent in species’ range information will soon reflect transient rather than steady-state conditions (Figure 1). While vagile, fast-reproducing plant and animal species may track shifts in climate and its impacts on key resources (Tingley et al. 2009), the abundance and spatial distribution of many species will diverge more and more from their historical climate limits. High rates of environmental change imply that distributional data will contain less and less information about species’ niches. The farther the planet moves away from the pre-Anthropocene biome configuration, the more important it will become to model community reassembly into new configurations. Observations are urgently needed to provide a baseline global inventory of the biosphere. This information will be critical for developing robust relationships between environmental characteristics and biotic properties. It will also serve as a useful initial condition for describing the current state of the terrestrial biosphere that can be used to form the baseline for global ecological forecasts. Given our current state of knowledge, we cannot know at REVIEWS REVIEWS REVIEWS