@article {753,
	title = {Human impacts, plant invasion, and imperiled plant species in California},
	journal = {Ecological Applications},
	volume = {16},
	year = {2006},
	month = {2006},
	pages = {1338-1350},
	abstract = {Invasive species are one of the fastest growing conservation problems. These species homogenize the world{\textquoteright}s flora and fauna, threaten rare and endemic species, and impose large economic costs. Here, we examine the distribution of 834 of the more than 1000 exotic plant taxa that have become established in California, USA. Total species richness increases with productivity; however, the exotic flora is richest in low-lying coastal sites that harbor large numbers of imperiled species, while native diversity is highest in areas with high mean elevation. Weedy and invasive exotics are more tightly linked to the distribution of imperiled species than the overall pool of exotic species. Structural equation modeling suggests that while human activities, such as urbanization and agriculture, facilitate the initial invasion by exotic plants, exotics spread ahead of the front of human development into areas with high numbers of threatened native plants. The range sizes of exotic taxa are an order of magnitude smaller than for comparable native taxa. The current small range size of exotic species implies that California has a significant {\textquoteleft}{\textquoteleft}invasion debt{\textquoteright}{\textquoteright} that will be paid as exotic plants expand their range and spread throughout the state.},
	keywords = {California, dispersal, exotic plants, extinction, global biodiversity hotspot, habitat loss, invasive species, rare species, species richness, structural equation models},
	url = {http://www.esajournals.org/esaonline/?request=get-abstract\&issn=1051-0761\&volume=016\&issue=04\&page=1338},
	author = {Seabloom, E. W. and Williams, J. W. and Slayback, D. and Stoms, D. M. and Viers, J. H. and Dobson, A. P.}
}
@article {830,
	title = {Impacts of Nitrogen Deposition on California Ecosystems and Biodiversity},
	year = {2006},
	month = {2006},
	pages = {68},
	institution = {University of California Santa Barbara and Creekside Center for Earth Observations},
	address = {Santa Barbara},
	abstract = {Recognized as a "biodiversity hotspot," California supports numerous endemic taxa with narrow ranges, and that diversity may be threatened by atmospheric nitrogen deposition. This California-wide risk screening included: (1) a 36 x 36 kilometer (km) map of total Nitrogen (N)-deposition for 2002, developed from the Community Multiscale Air Quality Model (CMAQ); (2) identification of sensitive habitats; (3) an overlay of the Forest Resource and Protection (FRAP) vegetation map; (4) an overlay of animal and plant species occurrence data from the California Natural Diversity Data Base (CNDDB); (5) an initial analysis of species life history and habitat; and (6) a discussion of relevance and guidance for assessments of power plant impacts. An area of 55,000 square kilometers (km2) of California is exposed to more than 5 kilograms of N per hectare per year (kg-N ha-1 year-1), and 10,000 km2 are exposed to more than 10 kg-N ha-1 year-1. Deposition hotspots include: Los Angeles-San Diego, the San Francisco Bay Area, the Central Valley, and the Sierra Nevada foothills. The major documented impact of N-deposition on California terrestrial biodiversity is to increase invasive annual grasses in low biomass ecosystems, resulting in species loss. Of 225 "threatened" and "endangered" plant taxa, 99 are exposed to an average > 5 kg-N ha-1 year-1. Of 1,022 "rare" plant taxa, 290 are exposed to > 5 kg-N ha-1 year-1. Listed animal species follow similar patterns. This initial screening outlines potential impacts on California{\textquoteright}s biodiversity and provides targeted guidance for assessing the impacts of power plant and other sources of atmospheric N-deposition.},
	keywords = {annual grasses, biodiversity, California, deserts, eutrophication, grasslands, invasive species, nitrogen deposition, threatened and endangered species},
	isbn = {CEC-500-2005-165},
	url = {http://www.energy.ca.gov/pier/final_project_reports/CEC-500-2005-165.html},
	author = {Weiss, Stuart B.}
}
