Dean of Rausser College of Natural Resources UC Berkeley, California, United States
Abstract: Trait-based ecology encompasses a suite of approaches linking the functional characteristics of organisms to questions in evolutionary biology, community ecology, and global change biology. Traits may include morphological, physiological, or behavioral attributes. In addition, the environmental, habitat, or climate conditions occupied by an individual organism, population, or species, is often treated as an attribute. Climate conditions, in particular, are easily measured by overlaying species distribution maps, occurrence locations, or distribution models on climate maps, and calculating the species average or optimal climate niche for different climate parameters (temperature, precipitation, etc.). The climate niche can be treated like any other trait value, and has been especially valuable in community and landscape ecology: community mean values of the climate niche provide a simple quantitative descriptor for a set of cooccurring species. Spatial patterns in community weighted means serve as a biotic measure of microclimate variation, and shifts in community weighted means offer an indicator of community response to global change (e.g., community ‘thermophilization’).
The presentation will review methods for calculating climate niche values, and identify pros and cons relative to different applications, and then consider several conceptual questions about the use and interpretation of species climate niche values: In what ways are they similar or different from functional traits measured directly on the organism? To what extent is the climate niche an attribute of a species, vs. an outcome that reflects the interaction of traits and environment that shapes species distributions? What are the ecological factors shaping apparent patterns of niche conservatism and niche evolution? How can we improve and standardize methods for calculating climatic niche values to maximize their value in ecological research? The questions will be illustrated with recent examples from the author’s lab, including evolutionary correlations of climate niche and drought tolerance traits, and new studies showing thermophilization of Western US forests.
