PARENT SESSION
Oral Session #45: Biogeography and Metapopulations.
Presiding: T. Miller
Tuesday, August 6. 1:00 PM to 4:45 PM. Grand Ballroom Central, Radisson.
How many species? An analysis of North American floras.
Palmer, Michael*,1, Earls, Peter1, White, Peter2, Wade, Gary3, Withers, Mark4, 1 Oklahoma State University, Stillwater, OK2 University of North Carolina - Chapel Hill, Chapel Hill, NC3 USDA Forest Service - Northeastern Research Station, Burlington, VT4 University of Washington, WA
ABSTRACT- Floras are defined here as lists of vascular plants intended to represent the species present in a defined location. We assembled a bibliography of >5000 floras from North America, north of Mexico, and compiled summary information such as year of study, latitude, longitude, area, elevation, and number of families, genera, species, exotic species, and total taxa. We obtained reliable data from 1410 of these floras. Despite the limitations of floristic data (e.g. subjectivity; intrinsic incompleteness; problems with synonymy), we found strong patterns consistent with the literature. The number of species was positively correlated with area and negatively correlated with latitude and elevation. However, the effects of latitude and elevation were strongly scale-dependent. The percentage of exotic species did not increase dramatically through time, although exotic species were predictably related to latitude and elevation. Quantitative analysis of floras has direct applications for reserve design, restoration ecology, and biological surveys.
KEY WORDS: flora, species richness, biodiversity, biogeography