"Chapter one evaluated our field method using surface moisture classes at the end of August to track species change across the gradient in Kern Plateau meadows, California. As individual species distributions and composition as a whole changed across our a priori moisture classes, and as ordination results showed that moisture class described the majority of variation in species composition, we determined that this method was a good surrogate for the complex hydrologic gradient. Chapter two examined how impacts on physical characteristics in meadows affect biodiversity. Habitats were characterized by hydrology (moisture class), topography, and gross vegetation physiognomy. Species richness was significantly correlated with habitat richness but not species pool. Diversity on non-channel habitats significantly exceeded that of channel habitats when overhanging banks were removed from the analysis, highlighting the importance of overhanging banks on incised channels. Species richness was higher in dry habitats, but wet habitats had a higher proportion of meadow-dependent species. Stringers were significantly higher in species richness than main meadows. We concluded that habitat richness was more important than species pool in determining species richness, that non-channelized habitats and stringers contributed most to plant diversity, and that grazing intensity should be controlled in important habitat types: stringers, overhanging banks and willow. Chapter 3 addressed grazing impacts on channel morphology and incision, moisture class, and species composition by sampling southern Sierra Nevada grazed and ungrazed meadows. Grazed meadows had a significantly higher channel width-to-depth ratio than ungrazed meadows. Channel depth, channel width-to-depth ratio, grazing, and year all significantly affected moisture class distribution. Both greater width-to-depth ratios and grazing were associated with drier moisture classes. Ordination results indicated that grazing, year, and position in basin correlated with the first three axes, explaining 23% of the species data variation. Six ungrazed meadow indicator species, or 43%, were megaforbs, even though megaforbs constitute only 4% of the total flora. We concluded that cow/calf seasonal grazing is correlated with physical changes in meadow physiography, and that these changes affect moisture class availability and therefore habitat availability. Megaforbs are especially susceptible to impacts of grazing in montane and sub-alpine meadows."--Abstract

This long-anticipated reference and sourcebook for California’s remarkable ecological abundance provides an integrated assessment of each major ecosystem type—its distribution, structure, function, and management. A comprehensive synthesis of our knowledge about this biologically diverse state, Ecosystems of California covers the state from oceans to mountaintops using multiple lenses: past and present, flora and fauna, aquatic and terrestrial, natural and managed. Each chapter evaluates natural processes for a specific ecosystem, describes drivers of change, and discusses how that ecosystem may be altered in the future. This book also explores the drivers of California’s ecological patterns and the history of the state’s various ecosystems, outlining how the challenges of climate change and invasive species and opportunities for regulation and stewardship could potentially affect the state’s ecosystems. The text explicitly incorporates both human impacts and conservation and restoration efforts and shows how ecosystems support human well-being. Edited by two esteemed ecosystem ecologists and with overviews by leading experts on each ecosystem, this definitive work will be indispensable for natural resource management and conservation professionals as well as for undergraduate or graduate students of California’s environment and curious naturalists.

"This completely new edition of Terrestrial Vegetation of California clearly documents the extraordinary complexity and richness of the plant communities and of the state and the forces that shape them. This volume is a storehouse of information of value to anyone concerned with meeting the challenge of understanding, managing or conserving these unique plant communities under the growing threats of climate change, biological invasions and development."—Harold Mooney, Professor of Environmental Biology, Stanford University "The plants of California are under threat like never before. Traditional pressures of development and invasive species have been joined by a newly-recognized threat: human-caused climate change. It is essential that we thoroughly understand current plant community dynamics in order to have a hope of conserving them. This book represents an important, well-timed advance in knowledge of the vegetation of this diverse state and is an essential resource for professionals, students, and the general public alike."—Brent Mishler, Director of the University & Jepson Herbaria and Professor of Integrative Biology, University of California, Berkeley

Upper montane meadows are keystone areas of ecological importance within a forested landscape: Although montane meadows comprise less than 10% of the Sierra Nevada, they represent tremendous ecological, social, and economic importance. Meadows are highly productive and provide numerous ecosystem services, such as wildlife habitat, flood flow retention and maintenance of summer stream baseflows, and forage production for permitted cattle grazing. Because montane meadows provide for these multiple uses, there has been considerable concern regarding potential detrimental effects of livestock grazing on meadow functioning, especially in high elevation systems on US Forest Service lands. Public lands grazing in higher elevation range is crucial to sustaining many Sierra foothill ranching operations: In the Sierra foothills, forage quality and livestock performance is generally low throughout the inadequate dry forage period (i.e., summer season), and so managers must seek alternative feed sources (e.g., high elevation grazing leases) during this time. For these reasons, there is a growing amount of interest and examination of the potential impacts of cattle grazing on meadow functions and ecosystem services. This research was part of a larger collaborative effort, the Yosemite Toad Adaptive Management Project, between the USDA Forest Service-Pacific Southwest Region, UC Berkeley, and UC Davis. The overall project included multiple experimental approaches to investigate the potential impacts of cattle grazing on a sensitive amphibian species, Yosemite toads (Bufo canorus Camp), and its meadow habitat. In the first study, we investigated the potential to alleviate possible negative grazing impacts on hydrologic, water quality, and cover habitat conditions via cattle exclusion treatments. Our objectives were to: 1) Determine associations between breeding pool habitat conditions and use of potential breeding pools by toads, and 2) Determine how habitat conditions respond to cattle exclusion treatments on the Sierra National Forest, California. We randomly selected two toad occupied and two unoccupied breeding pools in each of nine meadows for this study (n=36 breeding pools). After baseline data collection in 2006, three meadow fencing treatments were implemented over the course of three years. Treatments were fencing to exclude cattle from the entire meadow; fencing to exclude cattle from potential toad breeding and rearing areas, with grazing allowed in the remaining unfenced portion of the meadow; and cattle grazing allowed across the entire meadow. We monitored hydrologic, water quality, and cover habitat factors as well as toad occupancy during the breeding seasons of 2006 through 2008. Concentrations of water quality constituents were uniformly low all years, regardless of treatment. Occupied pools were shallower, warmer, and more nitrogen enriched than unoccupied breeding pools. We found no evidence of improved toad breeding pool habitat conditions following fencing compared to standard US Forest Service grazing management. The second study was a three year, cross-sectional observational survey of cattle grazing intensity and Yosemite toad occupancy of meadows across the extensive grazing landscape. We surveyed biotic and abiotic factors influencing cattle utilization and toad occupancy across 24 meadows to investigate potential associations between grazing and amphibian occurrence and inform conservation planning efforts. Toad occupancy, cattle utilization, plant community, and hydrologic data were collected within each meadow. Cattle use was negatively related to meadow wetness, while toad occupancy was positively related to meadow wetness. In mid and late season (mid July through mid September) grazing periods, cattle selected for higher forage quality diets associated with drier meadows. Bayesian structural equation model analyses supported the hypothesis that meadow wetness had a greater magnitude of influence on toad meadow occupancy than cattle grazing intensity. The third study focuses on the variation in soil and plant community properties, and associated ecosystem services, across grazed meadow catenas. This patch-level (i.e., within meadow) approach allowed us to: 1) Quantify patch-level relationships among wetness, plant community characteristics, and annual cattle utilization within meadows; and 2) Quantify and describe plant community and soil characteristics expressed across meadow catenas to evaluate the variation in--and 'compatibility' of--multiple ecosystem services across grazed meadows. We found significant differences in the levels of multiple ecosystem services provided across patch types. Drier (moist to mesic) patches provided greater forage quality value, and experienced greater grazing pressures. These patches also supported greater plant species richness and diversity. The wettest patch types, produced by season-long high water tables, had the greatest accumulations of soil organic matter, soil C, and soil N. There were no significant cattle grazing impacts on soil characteristics across patch types. Collectively, these findings suggest that cattle production, wildlife conservation, and maintenance of soil properties can be compatible goals within this working landscape. Loss of critical wet meadow habitat will have direct negative impacts on sensitive aquatic species and soil health; therefore, managing current land uses to maintain proper meadow functioning conditions, restoring sites degraded from past land use activities (i.e., legacy effects), and mitigating potential climate change impacts on meadow ecohydrology are vital to conservation of multiple ecosystem services.

Plant species diversity refers to variety and abundance; it does not necessarily relate to meadow health but may provide information important in an ecosystem context. Monitoring to detect change in diversity usually begins with estimating alpha (within) diversity of plant communities. Because few such estimates exist for meadow site classes or specific sites of the Sierra Nevada, California, we computed Margalef's diversity index (Dm), which stresses species richness, and Simpson's index (Ds), which stresses species dominance, for two sets of frequency data. Frequency was estimated by the nearest shoot-to-point method and the rooted quadrat method. In addition, a relative index (Dr) was calculated on the basis of the number of species on individual sites divided by the average number of species recorded for 107 meadow sites. Regardless of the data set or index, species diversity was lower for sites at or near the environmental extremes of moisture. The methods used to estimate frequency, estimating species numbers, and the value of diversity estimates are discussed.

Domestic livestock grazing on mountain meadows of the Sierra Nevada is highly controversial and has been associated with negative effects on meadow species and function. In light of these effects, the US Forest Service has implemented policy and grazing management changes over the last 20 years, including the Sierra Nevada Forest Plan Amendment, which offered increased restrictions on grazing and protection for endangered meadow species. Here we ask how policy-driven changes in grazing management and precipitation have influenced trends in plant community characteristics and function in high elevation meadows. We surveyed long-term monitoring sites on 30 meadows across 12 US Forest Service grazing allotments at approximately five-year intervals from 1999 to 2010. During the study period there were significant increases in species richness and diversity, but no significant changes in species evenness and soil stability provided by the plant community. Whether the site was grazed was not significantly correlated to changes in any of the plant community metrics, but precipitation and the frequency of perennial grasslike species were negatively related to species richness and diversity. The effects of precipitation on species evenness and soil stability were dependent upon site type, with the wettest meadow sites showing greater decreases in species evenness and increases in soil stability with increasing precipitation. These findings suggest that the current levels of grazing pressure, as enforced under the Sierra Nevada Forest Plan Amendment are not hindering the dynamics of mountain meadow plant communities. In the projected climate scenarios of a longer and drier growing season in the Sierra Nevada, the implications of the relationships between precipitation and meadow plant community attributes and function will likely become more important to the management of these systems. As species diversity and evenness appear to be oppositely related to changes in precipitation from soil stability, managers may increasingly have to balance goals for these contrasting indicators of meadow health.