PARENT SESSION
Oral Session #74: Spatial Ecology: Models and Methods. Presiding: C. Loehle.
Friday, August 10, 2001. 8:00 AM to 11:30 AM. Hall of Ideas E.
Testing for self-similarity in a serpentine ecosystem.
Green, Jessica1, Harte, John1, Ostling, Annette1, 1
ABSTRACT- In earlier work, it has been demonstrated that the power-law species-area relationship (SAR) and range-area relationship (RAR) implies self-similarity in the spatial distribution of species. Casting the SAR and RAR in the form of a self-similar scaling relationship results in a host of new and testable predictions fundamental to ecology, including a community-level and species-level abundance distribution, a power-law relationship between the abundance of a species and its geographic range size, and a theoretical expression relating the community-level and species-level self-similar parameters. To test this theory we collected plant census data from serpentine substrates at the Sylvia McLaughlin University of California Natural Reserve. We recorded the total abundance of every plant species within one 64 m2 plot gridded into 256 0.25 m2 squares. There were a total of 24 species and 37,182 individuals at the site, and the SAR is well fit by a power-law. The observed individual species abundance distributions and total abundance of each species are consistent with those predicted from the theory. The predicted slopes of plots of log(range size) versus log(abundance) are shown to be in good agreement with the data. The theoretical prediction linking the community-level and species-level self-similarity parameters estimate the correct SAR exponent at the site, z = 0.215.
KEY WORDS: species-area relationship, range-area relationship, self-similarity, serpentine grasslands