The semi-arid shrublands of Southern California are subject to some of the highest rates of atmospheric nitrogen deposition in North America. Little is known about the effects of nitrogen (N) pollution on drought-deciduous coastal sage scrub species (CSS) such as California sage (Artemisia californica) and black sage (Salvia mellifera), and sclerophyllous chamise chaparral species such as chamise (Adenostoma fasciculatum) that inhabit this region. This study monitored the photosynthetic and respiration rates, leaf conductance, leaf nitrogen content and specific leaf area of these species quarterly over the course of two years in a mature CSS stand and a pre-and post-fire chaparral stand. An in-situ experiment was conducted; half of the 10 X 10 meter study plots at each site were subjected to an additional 50 kg N ha-1 in the form of NH4N03 fertilizer in October of 2003 and 2004. The remaining plots served as controls subject to ambient N deposition. Rainfall dependent seasonal changes of these physiological measures that are typical of Mediterranean-type ecosystems were observed, however a multiple analysis of variance (MANOVA) indicates that there were no significant differences between control and experimental plots due to N addition. This may be due to the temporal asynchrony of the artificial nitrogen addition and seasonal rainfall, as the nitrogen was added in the fall when the shrubs are physiologically dormant (CSS) or minimal (CC). The first rains may have flushed the N into downslope streams, away from the rooting zones of the shrubs. Alternatively, the lack of significant differences may be because the shrubs had been engaging in luxury consumption, or were already existing in a state of N saturation. Key words: Adenostoma fasciculatum, Artemisia californica, Salvia mellifera, coastal sage scrub, chaparral, nitrogen deposition.

This thoroughly revised, entirely rewritten edition of what is the essential reference on California’s diverse and ever-changing vegetation now brings readers the most authoritative, state-of-the-art view of California’s plant ecosystems available. Integrating decades of research, leading community ecologists and field botanists describe and classify California’s vegetation types, identify environmental factors that determine the distribution of vegetation types, analyze the role of disturbance regimes in vegetation dynamics, chronicle change due to human activities, identify conservation issues, describe restoration strategies, and prioritize directions for new research. Several new chapters address statewide issues such as the historic appearance and impact of introduced and invasive plants, the soils of California, and more.

Chaparral shrubland ecosystems are an iconic feature of the California landscape, and a highly biodiverse yet highly flammable backdrop to some of the fastest growing urban areas in the United States. Chaparral-type ecosystems are a common element of all of the world’s Mediterranean-type climate regions – of which California is one – yet there is little public appreciation of the intrinsic value and the ecosystem services that these landscapes provide. Valuing Chaparral is a compendium of contributions from experts in chaparral ecology and management, with a focus on the human relationship with chaparral ecosystems. Chapters cover a wide variety of subjects, ranging from biodiversity to ecosystem services like water provision, erosion control, carbon sequestration and recreation; from the history of human interactions with chaparral to current education and conservation efforts; and from chaparral restoration and management to scenarios of the future under changing climate, land use, and human population. Valuing Chaparral will be of interest to resource managers, the research community, policy makers, and the public who live and work in the chaparral dominated landscapes of California and other Mediterranean-type climate regions.