1. ¹Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
2. ²Merriam-Powell Center for Environmental Research, Northern Arizona University, Flagstaff, AZ, USA
3. ³Conservation and Science Department, Lincoln Park Zoo, Chicago, IL, USA
4. ⁴School of Forestry, Northern Arizona University, Flagstaff, AZ, USA
5. ⁵Environmental Genetics and Genomics Laboratory, Northern Arizona University, Flagstaff, AZ, USA

Correspondence: Dr RK Bangert, Department of Biological Sciences, Northern Arizona University, PO Box 5640, Flagstaff, AZ 86011-5640, USA. E-mail: rkb@nau.edu

⁶Current address: Department of Entomology, University of Maryland, College Park, MD 20742, USA.

⁷Current address: Lab II, The Evergreen State College, Olympia, WA 98505, USA.

⁸Current address: Department of Ecology and Evolution, University of Tennessee, Knoxville, TN 37966, USA.

Received 30 April 2006; Revised 5 September 2006; Accepted 25 September 2006; Published online 18 October 2006.

Abstract

Understanding the local and regional patterns of species distributions has been a major goal of ecological and evolutionary research. The notion that these patterns can be understood through simple quantitative rules is attractive, but while numerous scaling laws exist (e.g., metabolic, fractals), we are aware of no studies that have placed individual traits and community structure together within a genetics based scaling framework. We document the potential for a genetic basis to the scaling of ecological communities, largely based upon our long-term studies of poplars (Populus spp.). The genetic structure and diversity of these foundation species affects riparian ecosystems and determines a much larger community of dependent organisms. Three examples illustrate these ideas. First, there is a strong genetic basis to phytochemistry and tree architecture (both above- and belowground), which can affect diverse organisms and ecosystem processes. Second, empirical studies in the wild show that the local patterns of genetics based community structure scale up to western North America. At multiple spatial scales the arthropod community phenotype is related to the genetic distance among plants that these arthropods depend upon for survival. Third, we suggest that the familiar species–area curve, in which species richness is a function of area, is also a function of genetic diversity. We find that arthropod species richness is closely correlated with the genetic marker diversity and trait variance suggesting a genetic component to these curves. Finally, we discuss how genetic variation can interact with environmental variation to affect community attributes across geographic scales along with conservation implications.