Many terrestrial plant communities, especially forests, have been shown to lag in response to rapid climate change. Grassland communities may respond more quickly to novel climates, as they consist mostly of short-lived species, which are directly exposed to macroclimate change. Here we report the rapid response of grassland communities to climate change in the California Floristic Province. We estimated 349 vascular plant species' climatic niches from 829,337 occurrence records, compiled 15 long-term community composition datasets from 12 observational studies and 3 global change experiments, and analysed community compositional shifts in the climate niche space. We show that communities experienced significant shifts towards species associated with warmer and drier locations at rates of 0.0216 +/- 0.00592 degrees C yr(-1) (mean +/- s.e.) and -3.04 +/- 0.742 mm yr(-1), and these changes occurred at a pace similar to that of climate warming and drying. These directional shifts were consistent across observations and experiments. Our findings contrast with the lagged responses observed in communities dominated by long-lived plants and suggest greater biodiversity changes than expected in the near future.

Woody plant encroachment into open grasslands occurs worldwide and causes multiple ecological and management impacts. Prescribed fire could be used to conserve grassland habitat but often has limited efficacy because many woody plants resprout after fire and rapidly reestablish abundance. If fire‐induced mortality could be increased, prescribed fire would be a more effective management tool. In California's central coast, shrub encroachment, especially of Baccharis pilularis (coyote brush), is converting coastal prairie into shrub‐dominated communities, with a consequent loss of native herbaceous species and open grassland habitat. B. pilularis has not been successfully controlled with single prescribed fire events because the shrub resprouts and reestablishes cover within a few years. We investigated whether two consecutive annual burns would control B. pilularis by killing resprouting shrubs, without reducing native herbaceous species or encouraging invasive plants. As expected, resprouting did occur; however, 2 years after the second burn, B. pilularis cover on burned plots was only 41% of the cover on unburned plots. Mortality of B. pilularis more than doubled following the second burn, likely maintaining a reduction in B. pilularis cover for longer than a single burn would have. Three native coastal prairie perennial grasses did not appear to be adversely affected by the two burns, nor did the burns result in increased cover of invasive species. Managers wanting to restore coastal prairie following B. pilularis encroachment should consider two consecutive annual burns, especially if moderate fire intensity is achievable.

Over eight years we measured the effects of plant community composition, vegetation structure, and livestock grazing on occurrence of three grassland bird species—Western Meadowlark (Sturnella neglecta), Horned Lark (Eremophila alpestris), and Grasshopper Sparrow (Ammodramus savannarum)—at sites in central California during breeding season. In California’s Mediterranean-type climatic region, coastal and inland grassland vegetation is dominated by exotic annual grasses with occasional patches of native bunchgrass and forbs. Livestock grazing, primarily with beef cattle, is the most widely used management tool. Compared with ungrazed plots, grazed plots had higher bare ground, native plant cover, and vertically heterogeneous vegetation. Grazed plots also had less plant litter and shorter vegetation. Higher native plant cover, which is predominantly composed of bunchgrasses in our study area, was associated with livestock grazing and north-facing aspects. Using an information theoretic approach, we found that all three bird species had positive associations with native plant abundance and neutral (Western Meadowlark, Grasshopper Sparrow) or positive (Horned Lark) association with livestock grazing. All species favored flatter areas. Horned Larks and Western Meadowlark occurred more often where there were patches of bare ground. Western Meadowlarks and Grasshopper Sparrows were most common on north-facing slopes, suggesting that these species may be at risk from projected climate change. These findings demonstrate that livestock grazing is compatible with or supports grassland bird conservation in Mediterranean-type grasslands, including areas with high levels of exotic annual grass invasion, in part because grazing supports the persistence of native plants and heterogeneity in vegetation structure. However, conservation of low-lying grasslands with high native species presence, and active management to increase the abundance of native plant species are also likely to be important for sustaining grassland birds long-term.

Ecological site descriptions and associated state-and-transition models are useful tools for understanding the variable effects of management and environment on range resources. Models for woody riparian sites have yet to be fully developed. At Tejon Ranch, in the southern San Joaquin Valley of California, we are using ecological site theory to investigate the role of two managed ungulate populations, cattle and feral pigs, on riparian woodland communities. Responses in plant species composition, woody plant recruitment, and vegetation structure will be measured by comparing cattle and feral pig management treatments among and between areas with similar abiotic conditions (ecological sites). Results from the second year of this project highlight the spatial variability of riparian woodland vegetation communities as well as temporally and spatially variable abundances of cattle and feral pigs. Development of riparian ecological site descriptions and state-and-transition models provide both a generalizable framework for evaluating management alternatives in riparian areas, and also specific direction for managing cattle and feral pigs.

On the Ground California's Mediterranean climate zone supports grasslands that are biologically diverse. Livestock grazing is being increasingly used to promote native species diversity at both the pasture and landscape scales. Several federally and state-listed vertebrates and insects respond positively to grazing to improve habitat by opening and lowering grassland vegetation. More work is needed on enhancement of native plants. Research results need to be more extensively applied, tested, and monitored under variable conditions.

While little research has been done on California grassland birds, their populations are thought to be declining due to habitat loss, fragmentation, and degradation. We investigated the association between California grassland birds and their landscape-scale habitat matrix. The habitat is a mosaic of valley grassland with blue oak and coast live oak woodlands. In this study, we used logistic regression to analyze presence of grasshopper sparrows (Ammodramus savannarum), horned larks (Eremophila alpestris), western meadowlarks (Sturnella neglecta), savannah sparrows (Passerculus sandwichensis), and the guild as a whole in response to patch size, cover-type richness, and proportion of high-intensity development, low-intensity development, deciduous forest, and evergreen forest in the landscape. These landscape variables were analyzed for the 2004 and 2005 breeding seasons at three spatial scales: 500 m, 1 km, and 2 km buffer zones from the point count center. We found that the grassland bird guild as a whole was positively associated with patch size, proportion of low-intensity development, and proportion of evergreen forest and negatively associated with cover-type richness, proportion of high-intensity development, and proportion of deciduous forest. Patch size and cover-type richness were the most commonly significant variables across spatial scales and across years. Individual species showed similar trends to that of the guild.

On 10 sloped grassland sites, 175 Nassella pulchra plants were randomly selected and their basal geometry measured. Plants were not circular (p < 0.001) with an average elongation of 30.3%+20.7 and 89% of the plants had greater than 10% elongation. Sixty-six percent of the plants had the elongation oriented along the contours. Elongation was correlated with slope steepness (p=0.003, r(2)=0.06), but unrelated to the angle the long axis was deflected from the slope fall line (p=0.21, r(2)=0.02). This elongation and orientation potentially reduced overland flow compared to circular plants.