DENTON, RENEE GENEVIEVE* AND RAYMOND D. RATLIFF. Forestry Sciences Lab, Pacific Southwest Research Station, 2081 E. Sierra Ave., Fresno, CA 93710. - Ecology and Management of Trifolium Bolanderi Gray. in the Central Sierra Nevada.
Trifolium bolanderi Gray. (Fabaceae) is a narrow endemic restricted
to meadows of the central Sierra Nevada of California extending from
Yosemite National Park to north of the King’s River. It occurs within
a narrow elevational band from 2134 m to 2165 m. The type location is
Westfall meadow in Yosemite National Park. Commonly called Bolander's
clover, it is federally designated by the U.S. Fish and Wildlife
Service as a 'species of concern'. Trifolium Bolanderi occurs on
grazed forest ranges, and its sensitive categorization influences land
use planning. Species Ecology--Reasons for its limited
distribution were investigated. According to park and forest records
(1990), there were only 20 meadows with known populations. Ratliff and
Denton (1993) examined 81 sites within 32 meadows, 10 meadows of which
were protected from livestock grazing. Sites having the target species
were compared to those without it. In terms of plant associations,
soils, hydrology, ground cover, and other micro-climatic site factors
for meadows, no biological reasons were reported (Ratliff and Denton
1993). Grazing Management--A study was initiated to evaluate
hypothetical response to defoliation. Clipping treatments were applied
in situ, at two clipping heights, 3cm and 6 cm. Clipping treatments
simulated grazing use: early season, season-long, deferred, and
deferred rotation grazing. One control plot per meadow was used. Plots
were circular 1/8 square meter, surrounded by a buffer, and caged from
herbivore use. Pre-clipping plant height was set a priori at 8cm.
Treatments continued every two weeks through the growing season and
were repeated over years. Twenty-two morphological
parameters are being evaluated. Above-ground responses include average
stem length, growth form, leaf length and number of flowers per head.
Below ground responses include number of active shoots from the crown,
crown diameter and length of the tap root. Statistical analysis will
employ a mixed-model ANOVA.
Key words: Fabaceae, herbivory, mountain meadow ecology, rare plants, Sierra Nevada, Trifolium bolanderi