PARENT SESSION
Poster Session #54: Plant Ecology: Communities.
Thursday, August 8. Presentation from 8:00 AM to 9:30 AM. Exhibit Hall B & C, TCC

Local ecology and geographical affinities of plants in the Bishop Creek watershed of the eastern Sierra Nevada, California.

Kimball, Sarah^*,1, Wilson, Paul¹, Crowther, Pat¹, Crowther, Jack¹, ¹ Department of Biology, Northridge, CA

ABSTRACT- The physiological requirements and tolerances of a species partially determine its habitat preferences within a community and its broader geographic range. We recorded all plant species growing in each of 263 plots above 2750 m elevation within the Bishop Creek drainage. The local habitat preferences of 362 species were described based on plot data. The size and center of the range for each species were determined from the floristic literature. Wetness preference within the watershed was significantly correlated with range size. Specifically, plants of wet sites had larger ranges and were from the north, whereas plants of dry sites tended to have smaller ranges centered to the east. The correlation between local wetness preference and range size persisted even when the direction of the center of the range was held constant. One possible explanation is that mesic habitats are and have long been available throughout the western Corilleran. In contrast, species adapted to xeric conditions have been poorly connected to high elevation dry sites. The dry-site species in our study area tended to be from high mountains to the east, and some have diverged from their relatives in those mountains. This implies that the elevational preferences of plant species, corrected by latitude, are evolutionarily fairly static. Sierran endemics tend to occupy dry, high elevation sites.

KEY WORDS: biogeography, Sierra Nevada, endemism, vegetation