PARENT SESSION
Oral Session # 62: Biodiversity I.
Presiding: P Baker
Thursday, August 7. 8:00 AM to 11:30 AM, SITCC Meeting Room 100.
Patterns of species and habitat richness and diversity in grazed meadows in the eastern Sierra Nevada.
Murrell, Kathren*,1, Dennis, Ann2, Barbour, Michael3, 1 University of California at Davis, Davis, CA2 CAL FLORA, Albany, CA3 University of California at Davis, Davis, CA
ABSTRACT- The Golden Trout Wilderness study examined how impacts on physical characteristics of meadows affect biodiversity. Our hypothesis was that meadow species richness is related to the range of habitats represented, and that richness within specific affinity groups is related to the representation of the habitat those species depend upon. An alternate hypothesis was that meadow area was more important than habitat in determining species richness. Species richness and habitat richness were positively correlated at R2= .53 and Prob>[t]=.0109. Neither the correlation between meadow size and species richness nor the correlation between meadow size and habitat richness was significant. Species diversity peaked at an intermediate level of habitat diversity (R2= .69 and Prob>[t]=.0023), suggesting that some habitats did not contribute substantially to species diversity. As a result of these analyses, we hypothesized that habitats in recently incised or degraded channels contribute less to species diversity than non-channel habitats. When analyzed separately, non-channel habitat diversity and species diversity displayed a positive linear correlation with an R2= .43 and Prob>[t]=.02. According to Tukey's comparison of means, non-channel transects contributed more to species richness than channel transects, and stringers had significantly higher species richness than meadow sampling units. Results also indicated that a group of species missing in grazed meadows in the Southern Sierra Nevada were also absent in grazed meadows in this study where sod banks, willows and stringers provided the only remaining habitat. We concluded that in these meadows, habitat richness was more important than meadow area in determining species richness, and that non-channelized habitats and stringers contributed the most to plant diversity.
Key words: biodiversity, meadows, Sierra Nevada