@article {695, title = {The Impact of Climate Change on California Timberlands}, year = {2009}, month = {2009}, pages = {52}, institution = {Conservation International and University of California Santa Barbara}, abstract = {

California timber production has been declining in an era of warming, increased wildfires, land use change, and growing emphasis on recreation. Climate change has the potential to further affect the California timber production and prices. The direction and magnitude of change will depend on individual site characteristics and projected climate change. Examples of potential climate change effects include changes in individual tree growth rates, forest dieback, and shifts in species ranges and ecosystem composition. When coupled with changes in global timber prices, which themselves are the result of productivity changes, this leads to important consequences to California\&$\#$39;s private timberlands. The ecological responses to climate change are dynamic and these complexities should be considered when predicting future timber production in California. Past attempts have modeled climate change impacts on the timber industry in California but did not consider dynamic land-use change or biologically relevant spatial resolution. This study uses models that project tree species productivity and movement across the landscape under climate change, coupled with economic models of landowner adaptation and returns from multiple harvest strategies. Our results show that under likely price scenarios, climate change will result in an overall decline in the value of harvested timber in the state, with decreases of 4.9 percent to 8.5 percent by the end of the century, depending on climate change scenario, price scenario and management option, with dollar losses totaling up to $8.1 billion. There is great spatial variation within these statewide averages. Many areas of the state show substantial declines in timber value, while a smaller number of areas show modest increases in value, under price scenarios that reflect the impact of climate change. If prices are not affected by climate change, more areas experience gains in value. Management options influence the degree of loss, indicating that programs fostering adaptation to climate change may pay important economic benefits. Declining timber value corresponds disproportionately to areas already experiencing conversion of timberlands to housing or agriculture. Policy measures to stem conversion of timberlands due to climate change may warrant consideration.

}, keywords = {California, carbon credit, climate change, growth rate, timber}, isbn = {CEC-500-2009-045-F}, url = {http://www.energy.ca.gov/2009publications/CEC-500-2009-045/CEC-500-2009-045-F.PDF}, author = {Hannah, L. and Costello, Chris and Guo, Chris and Ries, Lydia and Kolstad, Charles and Snider, Nathan} } @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.} } @article {832, title = {Anthropogenic impacts upon plant species richness and NPP in California}, journal = {Ecology Letters}, volume = {8}, year = {2005}, month = {2005}, pages = {127-137}, abstract = {We assess the importance of anthropogenic land-use, altered productivity, and species invasions for observed productivity-richness relationships in California. To this end, we model net primary productivity (NPP) c. 1750 AD and at present (1982-1999) and map native and exotic vascular plant richness for 230 subecoregions. NPP has increased up to 105\% in semi-arid areas and decreased up to 48\% in coastal urbanized areas. Exotic invasions have increased local species diversity up to 15\%. Human activities have reinforced historical gradients in species richness but reduced the spatial heterogeneity of NPP. Structural equation modelling suggests that, prior to European settlement, NPP and richness were primarily controlled by precipitation and other abiotic variables, with NPP mediating richness. Abiotic variables remain the strongest predictors of present NPP and richness, but intermodel comparisons indicate a significant anthropogenic impact upon statewide distributions of NPP and richness. Exotic and native species each positively correlate to NPP after controlling for other variables, which may help explain recent reports of positively associated native and exotic richness.}, keywords = {California, human impacts, Land cover change, net primary productivity, species richness, structural equation models}, url = {://000226491200001}, author = {Williams, J. W. and Seabloom, E. W. and Slayback, D. and Stoms, D. M. and Viers, J. H.} } @article {814, title = {Reproduction and growth of the chaparral geophyte, Zigadenus fremontii (Liliaceae), in relation to fire}, journal = {Plant Ecology}, volume = {165}, year = {2003}, month = {2003}, pages = {11-20}, abstract = {Zigadenus fremontii is often a striking component of the flora following fire in the chaparral. Like other geophytes, it produces large numbers of flowers in the first spring after a burn. Although these plants are most conspicuous in the early postfire environment, the question that remains is, how do they persist in the interval between fires? To address this we investigated differences in the growth and reproduction of Z. fremontii in burned and unburned chaparral. We monitored marked individuals for nine years at three sites: two that were burned in 1990 and one in the same area that was in unburned mature chaparral. We measured leaf area, and production of flowers and fruits. We also conducted seed experiments in the field to determine the rates and timing of germination. We found that reproduction occurs only in the immediate postfire period: flowering and production of fruits and seeds in the first year following fire, and seedling establishment by year 3. There was a cost of reproduction; plants that flowered (in the burn area) had negative growth rates the following year. In contrast, plants in unburned chaparral, which did not flower, had positive growth rates over the same period. Moreover, plants that produced the most flowers had the lowest growth rates. In the unburned chaparral site, plants were not dormant as predicted from previous literature; instead they produced leaves nearly every year. In most years the average leaf area per plant was greater than that in the burned sites. Our results indicate that postfire reproduction depends on growth and carbohydrate storage in the inter-fire period. We also suggest that this species is relatively long-lived for a herbaceous perennial.}, keywords = {bulb, California, fire-dependent reproduction, fire-induced flowering, germination, life-history, long-lived, pityopsis-graminifolia, populations, postfire, seedling establishment, soil fertility}, url = {://000179659700002}, author = {Tyler, C. and Borchert, M.} } @article {790, title = {Potential NDVI as a baseline for monitoring ecosystem functioning}, journal = {International Journal of Remote Sensing}, volume = {21}, year = {2000}, month = {2000}, pages = {401-407}, abstract = {Baseline data are needed to determine the overall magnitude and direction of change in ecosystem functioning. This letter presents an approach to estimate potential NDVI from environmental variables and training data of actual NDVI in nature reserves. Patterns of deviations of actual NDVI from the baseline generally correspond with land-use types in the western United States.}, keywords = {AVHRR, California, GAP, managed areas, NDVI, net primary production, NPP, Oregon, regression tree analysis, time integrated NDVI, Washington}, url = {://000084681200014}, author = {Stoms, D. M. and Hargrove, W. W.} } @inbook {395, title = {Selecting biodiversity management areas}, booktitle = {Sierra Nevada Ecosystem Project: Final Report to Congress, vol. II, Assessments and scientific basis for management options}, year = {1996}, pages = {1503-1528}, publisher = {University of California, Centers for Water and Wildlands Resources}, organization = {University of California, Centers for Water and Wildlands Resources}, address = {Davis, California}, abstract = {Here we present and evaluate a conservation strategy whose objective is to represent all native plant communities in areas where the primary management goal is to sustain native biodiversity. We refer to these areas as Biodiversity Management Areas (BMAs), which we define as specially designated public or private lands with an active ecosystem management plan in operation whose purpose is to contribute to regional maintenance of native genetic, species and community levels of biodiversity, and the processes that maintain that biodiversity. Our purpose in this chapter is to explore opportunities for siting BMAs in the Sierra Nevada region. The strategic goal is to design a BMA system that represents all major Sierran plant community types, which we use as a coarse surrogate for ecosystems and their component species. We consider a community type to be represented if some pre-defined fraction of its mapped distribution occurs in one or more BMAs. We use a multi-objective computer model to allocate a minimum of new land to BMA status subject to the constraints that all community types must be represented, and that the new BMA areas should be located in areas of highest suitability for BMA status. Our purpose in this exercise is not to identify the optimal sites for a Sierran BMA system; instead it is to measure some of the likely dimensions of plausible, alternative BMA systems for the Sierra Nevada and to develop a rationale that would guide others in formulating such a system. Thus we examine a wide range of possible BMA systems based on different assumptions, constraints, target levels for representation, and priorities. If one ignores current land ownership and management designations and sets out to represent plant communities in a BMA system based on Calwater planning watersheds (which average roughly 10,000 acres in size), an efficient BMA system requires land in direct proportion to the target level, at least over the range of target levels examined in this study. In other words, it takes roughly 10\% of the region to meet a 10\% goal, and 25\% of the region to meet a 25\% goal. The pattern of selected watersheds is very different from the current distribution of parks and wilderness areas, which are concentrated at middle and high elevations in the central and southern portion of the range. Public lands alone are insufficient to create a BMA system that adequately represents all plant community types of the Sierra Nevada. Many of the foothill community types occur almost exclusively on private lands. Terrestrial vertebrates are reasonably well represented in a BMA system selected for plant communities. A BMA system selected for vertebrates alone, however, has little overlap with the one for plant communities. Areas selected by the BMAS model show only a modest amount of overlap with areas selected by other SNEP working groups as focal areas for conserving aquatic biodiversity or late successional/old growth forests. However, the BMAS model can be formulated to favor these areas with little loss of efficiency, especially in the northern Sierra.}, keywords = {biodiversity management area, BMAS model, California, representation, reserve selection, Sierra Nevada}, author = {Davis, F. W. and Stoms, D. M. and Church, R. L. and Okin, W. J. and Johnson, K. N.} } @inbook {392, title = {Sierran vegetation: A gap analysis}, booktitle = {Sierra Nevada Ecosystem Project: Final Report to Congress, vol. II, Assessments and scientific basis for management options}, year = {1996}, pages = {671-689}, publisher = {University of California, Centers for Water and Wildlands Resources}, organization = {University of California, Centers for Water and Wildlands Resources}, address = {Davis, California}, abstract = {Gap analysis assesses the distribution of plant community types and vertebrate species distributions among land classes defined by ownership and levels of protection of biodiversity. Gap analysis helps to identify which plant communities and species might be especially vulnerable to different human activities that can lead to habitat conversion or degradation. This chapter presents a gap analysis of plant community types the Sierra Nevada region, an area of 63,111 km2 (24,368 mi2). Ownership of the region is 37\% private, 47\% national forests, 10\% national parks, 5\% Bureau of Land Management, and less than 2\% in other public lands. Land ownership and land management patterns contrast sharply between the northern Sierra Nevada versus the central and southern subregions. Parks and reserve lands contribute less than 2\% of the northern region versus 27\% of the central/southern. We mapped eighty-eight natural plant community types within the region. Sixty-seven types were mapped over areas greater than 25 km2 (9.65 mi2). The ownership profiles of Sierran plant communities systematically reflect the concentration of private lands at lower elevations and of national parks in the central and southern portion of the range. Less than 1\% of the foothill woodland zone of the Sierra Nevada is in designated reserves or other areas managed primarily for native biodiversity, and over 95\% of the distribution of most foothill community types is available for grazing. Low to middle elevation Sierran forests are not well represented in designated reserves, especially in the northern Sierra Nevada. However, large areas of most of these forest types on U.S. Forest Service lands have been administratively withdrawn from intensive timber management based on current forest plans. Many high-elevation forest and shrubland community types are well represented in parks and ungrazed wilderness areas. Our analysis identifies thirty-two widespread community types whose conservation status warrants concern and twelve types that appear well protected based on their present distributions.}, keywords = {California, gap analysis, land management, Sierra Nevada, vegetation}, author = {Davis, F. W. and Stoms, D. M.} } @article {389, title = {Gap analysis of the actual vegetation of California: 1. The Southwestern Region}, journal = {Madrono}, volume = {42}, number = {1}, year = {1995}, pages = {40-78}, abstract = {Gap Analysis is a method of conservation risk assessment that evaluates the protection status of plant communities, animal species and vertebrate species richness by overlay of biological distribution data on a map of existing biological reserves. The National Biological Survey has undertaken a national Gap Analysis that is being conducted by individual states but that will eventually produce regional and national assessments. Given California{\textquoteright}s size and complexity, we are conducting separate Gap Analyses for each of the state{\textquoteright}s 10 ecological regions, as delineated in The Jepson Manual. Here we summarize our findings on the distribution of plant communities and dominant plant species in the Southwestern Region of California, exclusive of the Channel Islands. We tabulate and discuss regional distribution patterns, management status and patterns of land ownership for 76 dominant woody species and 62 natural communities. Nineteen of 62 mapped communities appear to be at risk, as determined by their poor representation in existing reserves, parks or wilderness areas. Communities restricted largely to the lower elevations, such as non-native grasslands and coastal sage scrub types, are clearly at considerable risk. A majority of the lands at these elevations have already been converted to agricultural or urban uses and most of the remaining lands are threatened with future urbanization. Areas that appear to be of highest priority for conservation action based on agreement between our analysis and a recent assessment by The Nature Conservancy include the Santa Margarita River, San Mateo Creek, Miramar Mesa, Santa Clara floodplain near Fillmore, Sespe and Piru Canyons, and Tejon Pass.}, keywords = {California, gap analysis, vegetation}, author = {Davis, F. W. and Stine, P. A. and Stoms, D. M. and Borchert, M. I. and Hollander, A. D.} } @inbook {638, title = {Sensitivity of fire regime in chaparral ecosystems in climate change}, booktitle = {Ecological Studies Analysis and Synthesis, Vol. 117. Global change and mediterranean-type ecosystems; International Symposium, Valencia, Spain, September 1992}, year = {1995}, month = {1995}, pages = {435-456}, publisher = {Springer-Verlag New York, Inc.}, organization = {Springer-Verlag New York, Inc.}, address = {New York, New York, USA; Berlin, Germany}, keywords = {(Biophysics--Biocybernetics (1972- )), (Ecology, (General Biology--Information, Documentation, Retrieval and Computer Applications), (Mathematical Biology and Statistical Methods), Book Chapter, California, Computer Simulation, Ecology, Environmental Biology--Bioclimatology and Biometeorology), Environmental Biology--Plant), Fire History, Mathematical Model, Meeting Paper, Plantae-Unspecified, Plants, Usa, vegetation}, author = {Davis, F. W. and Michaelsen, J.}, editor = {Moreno, J. M. and Oechel, W. C.} } @article {375, title = {Information analysis of a spatial database for ecological land classification}, journal = {Photogrammetric Engineering \& Remote Sensing}, volume = {56}, number = {5}, year = {1990}, pages = {605-613}, keywords = {Burton Mesa, California, DEM data, entropy, GIS, map errors, mutual information analysis, TMS, vegetation pattern}, author = {Davis, F. W. and Dozier, J.} } @article {376, title = {Modeling vegetation pattern using digital terrain data}, journal = {Landscape Ecology}, volume = {4}, year = {1990}, pages = {69-80}, keywords = {California, coast live oak forest, DEM, geology, GIS, Lompoc, remote sensing, solar radiation}, author = {Davis, F. W. and Goetz, S.} }