negatively affected by disturbance. meadow barley (Hordeum brachyantherum Nevski) (Hickman 1993). Purple needlegrass, blue wildrye, bluegrass and California melic are droughttolerant species that typically occupy well-drained upland sites. In contrast, creeping wildrye and meadow barley are less drought-tolerant and typically grow in the moist soils of seeps, streams and wetland margins (Walker...

Private landowners are often de facto stewards of biodiversity and ecosystem services. In California’s Sierra Nevada foothills, ranchers frequently present the only defense against biological invasions in private rangelands. Although ranchers’ land management goals (e.g., the desire to control invasive species) can be consistent with ecosystem protection, practical constraints often limit their...

Hyperspectral remote-sensed data were obtained via a Compact Airborne Spectrographic Imager-II (CASI-II) and used to estimate leaf-area index (LAI) and aboveground biomass of a highly invasive weed species, yellow starthistle (YST). In parallel, 34 ground-based field plots were used to measure aboveground biomass and LAI to develop and validate hyperspectral-based models for estimating these me...

Pre-dispersal seed predators are often chosen as biocontrol agents because of their high impacts on plant fitness; however, they have a mixed record in realizing decreased plant population growth. Few studies have experimentally removed agents to explore their impact on weed population growth. Here, we used manipulative experiments with invasive yellow starthistle (YST), Centaurea solstitialis,...

Effective management of invasive species requires that we understand the mechanisms determining community invasibility. Successful invaders must tolerate abiotic conditions and overcome resistance from native species in invaded habitats. Biotic resistance to invasions may reflect the diversity, abundance, or identity of species in a community. Few studies, however, have examined the relative im...