Choosing (and making available) the right environmental layers for modeling how the environment controls the distribution and abundance of organisms

• Brian McGill
• Robert Guralnick
• Walter Jetz
• Jana McPherson

Abstract
We seek to understand how the environment controls species distributions. Despite the fact that a great deal of work in physiology has been done on this problem and that literally thousands of niche models (regressions of distribution on environment) have been run, we know surprisingly little about basic questions. Which aspects of environment are most central in controlling the distribution and abundance of organisms? How does this change with organism? with scale? what are the mechanisms linking environment to species distributions? We propose to assemble a state-of-the-art set of environmental layers that incorporate well-known but rarely used measures that have direct links to physiological processes like frost, water stress, growing season, soil properties, drainage properties, etc. We will assemble these variables into a unified, global, gridded, high resolution data set that will be made available to the public. This will be of enormous benefit to the community. We will use this data to explore the above-mentioned basic questions about the nature of the links between the environment and the distribution of organisms.