Search

The Pacific Crest Trail (PCT) is a National Scenic Trail that extends approximately 2,653 miles from the border of California and Mexico to the border of Washington State and Canada. This study examined land management and hiker issues that day, overnight, and thru-hikers experience in California while navigating the PCT in order to inform land managers. This quantitative survey, completed through Qualtrics, was disseminated to thru-hikers who completed the trail between 2017 and 2021, and individuals who used the trail for shorter durations. Survey questions focused on technology, Trail Angels, rule enforcement by land management agencies, the permitting process by the Pacific Crest Trail Association (PCTA), hiker education, and hiker demographics. Descriptive statistics were calculated and analyzed. Results indicate that most hikers prefer articles on the PCTA website, Leave No Trace (LNT) website, and certifications to gain education about the trail. They also felt that personal contacts were the most effective way to gain pre-trip education. Almost all hikers use technology on the trail, such as navigation or informational apps, emergency calls, taking photos, and listening to videos or music. More thru-hikers rely on navigational apps than day/overnight users. Many hikers felt there should be more rangers in the backcountry but also felt that social enforcement of rules is effective. Regarding Trail Angels, thru-hikers felt they were important for transportation, food/water, and shelter. Managerial implications for public land managers included a need to develop ways to educate users. This can be done in-person, online, or through signage. Increasing the presence of rangers or volunteers on the trail was also recommended, as well as developing area or jurisdiction-specific apps for information and education about trail conditions or rules. Additional education of sustainable hiking behaviors may help mitigate potential negative impacts hikers may have on the environment. Land managers must continue to assess what is currently being done and reevaluate on an ongoing basis in order to preserve and maintain sustainable use of public lands.

The Pacific Crest Trail is a National Scenic Trail that runs from Mexico to Canada. Use of the Pacific Crest Trail (PCT) has increased in the past 20 years. It is important to understand how an increase in use can impact the environment and sustainable practices, land management practices, and the hiker experience. Participants included 15 land managers in California and 25 thru-hikers who completed the PCT. In-depth interviews were conducted, and participants were asked questions about hiker interactions, trail angels, land manager interactions, and the permitting process. Data were transcribed verbatim and coded by three independent coders to reach a 90% inter-rater reliability. Emerging themes included: human impacts, permitting and education, and rule enforcement. Hikers also talked about the benefits of in-person education and the need for consistent communication between thru-hikers and land managers. Recommendations for sustainable practices include improvements to the permitting system, education, enforcement, and communication.

This article presents a watershed challenge that gives students an opportunity to investigate the challenge of using a watershed area as a site for development, examining the many aspects of this multifaceted problem. This design challenge could work well in a team-based format, with students taking on specific aspects of the challenges and pooling their ideas and research findings. The author describes how to stretch the challenge and consider taking this challenge another step.

Changes in land use and land cover, water systems, and climate are inextricably linked, and their combined stresses have had severe impacts in many regions worldwide. Integrated adaptation planning can support adaptive capacity by helping institutions manage land and water resources at regional to local scales. Linkages between these stressors mean that planners are often faced with potential trade-offs, and how to couple social and environmental sustainability remains a key question. We explore these questions in California's Central Coast, a region that is already experiencing serious water shortages, housing shortages, rapid expansion of perennial agriculture, and severe droughts that are projected to become worse with climate change. Linked models of land use change (the Land Use and Carbon + Water Simulator [LUCAS-W]), water resources (LUCAS-W), and climate (the Basin Characterization Model [BCM]) produced forecasts of exposure to regional changes at 270-m resolution. We worked with regional stakeholders to develop a matrix of nine vulnerability measures that assessed key sensitivities to these changes. Each vulnerability measure combined one of the three exposure projections with spatial datasets representing one of three sensitivity communities (agricultural, domestic, or ecological). We assessed how five scenarios of land-use and water management strategies under consideration by regional planners could provide institutional, top-down adaptive capacity, and whether there were trade-offs in sustainable development goals for these communities. We found that specific land and water management strategies could greatly reduce regional vulnerability, particularly programs to cap water extractions to sustainable levels. The most dramatic trade-off was between the strategy of water demand caps that increased risk of habitat loss and ecosystem preservation that increased water vulnerability. However, trade-offs were usually limited and spatially localized, suggesting local tailoring of the strategies we assessed could reduce them. Trade-offs were more frequent across exposure classes (land use vs. water vs. climate changes) rather than sensitivity classes (agricultural vs. domestic vs. ecological communities), suggesting win-win opportunities for natural resource management. Our vulnerability maps can inform prioritization efforts for local adaptation planning. [ABSTRACT FROM AUTHOR]

Aim: Rarity and geographic aspects of species distributions mediate their vulnerability to global change. We explore the relationships between species rarity and geography and their exposure to climate and land use change in a biodiversity hotspot. Location: California, USA. Taxa: One hundred and six terrestrial plants. Methods: We estimated four rarity traits: range size, niche breadth, number of habitat patches, and patch isolation; and three geographic traits: mean elevation, topographic heterogeneity, and distance to coast. We used species distribution models to measure species exposure—predicted change in continuous habitat suitability within currently occupied habitat—under climate and land use change scenarios. Using regression models, decision‐tree models and variance partitioning, we assessed the relationships between species rarity, geography, and exposure to climate and land use change. Results: Rarity, geography and greenhouse gas emissions scenario explained >35% of variance in climate change exposure and >61% for land use change exposure. While rarity traits (range size and number of habitat patches) were most important for explaining species exposure to climate change, geographic traits (elevation and topographic heterogeneity) were more strongly associated with species' exposure to land use change. Main conclusions Species with restricted range sizes and low topographic heterogeneity across their distributions were predicted to be the most exposed to climate change, while species at low elevations were the most exposed to habitat loss via land use change. However, even some broadly distributed species were projected to lose >70% of their currently suitable habitat due to climate and land use change if they are in geographically vulnerable areas, emphasizing the need to consider both species rarity traits and geography in vulnerability assessments. [ABSTRACT FROM AUTHOR]

Urban waterways degradation due to runoff from residential areas can be reduced by adopting best management practices (BMPs) for irrigation, fertilizer, and pesticide use. Although stormwater runoff from urban areas has been studied extensively, we focus on single-family residential land use specifically. Outreach to individual households may have a measurable impact since decisions are being made here. We surveyed households to evaluate the effectiveness of education and outreach campaigns on self-reported use of water and chemicals and evaluated whether self-reported behaviors were reflected in the quality and quantity of water draining from the study areas before and after outreach efforts. Our research was conducted in California, which has a Mediterranean climate with distinct wet and dry periods. Runoff from residential landscapes during the dry season enters waterways undiluted by rainwater, making this runoff particularly detrimental to receiving waters. No significant differences in behavior and BMP adoption from before and after the education and outreach campaign was found. These results are not atypical and may be explained by several factors including the population approach to the survey, lag times between outreach and measurable effects, and the need for a critical threshold of adoption to be met for effects to be measurable. [ABSTRACT FROM AUTHOR]

Ecocultural restoration involves the reciprocal repair of ecosystems and revitalization of cultural practices to enhance their mutual resilience to natural and anthropogenic disturbances and climate change stressors. Resilient ecocultural systems are adapted to retain structure and function in the face of disturbances that remain within historical ranges of severity. To assist in ecocultural restoration and management, understanding how a system has historically responded to different types of disturbances is therefore invaluable in understanding how social-ecological resilience can be maintained in the face of future stressors and disturbances. However, records of disturbances and ecocultural responses can be limited for certain landscapes and human communities. In this methods paper, we demonstrate a mixed-method process for integrating oral history, field-based knowledge, archival information, and historical and contemporary aerial images to gain insight into the changes on the Klamath River in Northern California from the 1940s through 2020. We georegistered historical imagery, quantified changes between land cover classes, and contextualized these classifications with qualitative assessments of changes in larger surrounding areas. By synthesizing these data sources with field measurements, mining and other land survey maps, timber management plans, fire and flood histories, and interviews with members of the Karuk Tribe, we were able to reconstruct the land use and land cover change histories at five sites. We noted that recovery of canopy cover from fire and logging practices was faster than for flood, which was faster than recovery from mining, consistent with the relative severity of likely soil disturbance. By combining different sources of information with complementary strengths, we were able to provide managers with site-specific information on recovery from different types of disturbance. Though this approach was labor-intensive, with emerging tools for supervised classification of high-resolution imagery, mixed-method analytical historical ecology could be applied more broadly, supporting ecocultural restoration on a larger scale. [Display omitted] • Reconstructing landscape histories helps understand ecosystem response to disturbance. • Combining qualitative and quantitative analysis helps reconstruct land-use. • Synthesizing many historical data sources improves ecocultural restoration planning. • Manual classification could improve with machine learning 'human-in-the-loop' tools. [ABSTRACT FROM AUTHOR]

This Article explores the slow-motion collision between two statutes at the center of California's housing crisis: the California Environmental Quality Act and the state's Housing Accountability Act. Each statute has a bonafide claim to being a "super-statute"--one that exerts a broad effect on the law. Yet the two statutes came of age in different eras--the California Environmental Quality Act in the 1970s and the Housing Accountability Act in the 2010s--and have fundamentally different institutional and normative premises. After tracing the evolution of the statutes, we explore two problems at their intersection: (1) cities' use of endless environmental review to launder the denial of housing projects that the Housing Accountability Act means to protect; and (2) analytical confusion about the proper scope of environmental review for projects protected by the Housing Accountability Act. We propose solutions that harmonize the two laws, remaining faithful to the text and purpose of the California Environmental Quality Act while fulfilling the Housing Accountability Act's instruction that it be interpreted "to afford the fullest possible weight to the interest of ... housing." Our solutions are not inevitable. In another possible future, the California Environmental Quality Act runs roughshod over the Housing Accountability Act, crippling California's efforts to provide more housing and, ironically, to respond to the threat of climate change. We hope this Article's intervention makes that future a bit less likely. [ABSTRACT FROM AUTHOR]

Cattle play an important role in wildfire management by grazing fuel on California rangelands. The benefits of cattle grazing have not been thoroughly explored, though. Using statewide cattle inventory, brand inspection and land use data, we have estimated that cattle removed 11.6 billion pounds (5.3 billion kilograms [kg]) of non-woody plant material from California's rangelands in 2017. Regionally, these reductions varied between 174 and 1,020 pounds per grazed acre (195 to 1,143 kg per hectare). Fire behavior is characterized in this paper by flame length. Fire behavior models suggest that these regional fuel reductions lower flame lengths, and lead to more manageable wildfires. In addition, fire-based models show that cattle grazing reduces fuel loads enough to lessen fire hazards in many grazed areas. Moving forward, there may be significant opportunities to expand strategic grazing on rangelands to add extra layers of protection against wildfires. [ABSTRACT FROM AUTHOR]

For millennia, forest ecosystems in California have been shaped by fire from both natural processes and Indigenous land management, but the notion of climatic variation as a primary controller of the pre-colonial landscape remains pervasive. Understanding the relative influence of climate and Indigenous burning on the fire regime is key because contemporary forest policy and management are informed by historical baselines. This need is particularly acute in California, where 20th-century fire suppression, coupled with a warming climate, has caused forest densification and increasingly large wildfires that threaten forest ecosystem integrity and management of the forests as part of climate mitigation efforts. We examine climatic versus anthropogenic influence on forest conditions over 3 millennia in the western Klamath Mountains—the ancestral territories of the Karuk and Yurok Tribes—by combining paleoenvironmental data with Western and Indigenous knowledge. A fire regime consisting of tribal burning practices and lightning were associated with long-term stability of forest biomass. Before EuroAmerican colonization, the long-term median forest biomass was between 104 and 128 Mg/ha, compared to values over 250 Mg/ha today. Indigenous depopulation after AD 1800, coupled with 20th-century fire suppression, likely allowed biomass to increase, culminating in the current landscape: a closed Douglas fir–dominant forest unlike any seen in the preceding 3,000 y. These findings are consistent with precontact forest conditions being influenced by Indigenous land management and suggest large-scale interventions could be needed to return to historic forest biomass levels. [ABSTRACT FROM AUTHOR]

The licensed cannabis industry represents one of the top five most economically valued agricultural commodities in California, yet farming largely remains on remote, environmentally sensitive, "marginal" lands. Using mixed methods, this paper examines the determinants of this marginalization, their embedded elaboration, and their relation to historical policy regimes. We used Generalized Additive Models (GAMs) to determine the most important predictors of licensed cannabis industry development since the inception of a statewide licensing program in 2018 and to compare the distribution of licensed cannabis to other forms of rural agriculture, including vineyards and pasture, to understand landscape factors and environmental sensitivity of land uses. We found that a county's median income and the extent of traditional (non-cannabis) agriculture, as measured by the proportion of on-farm (non-cannabis) employment, were both negatively associated with its amount of licensed cannabis agriculture. Ethnographic data suggests that cannabis is often excluded from traditional agricultural areas, through formal local-level bans, restrictive zoning, high "prime" farmland values, and cultural exclusions from other powerful resource users. The resulting relegation to "marginal" lands foments conflicts with amenity land users and environmentalists, even as it partly supports "legacy" cultivators whose farms were established under prior policy regimes. Results suggest that cannabis is more likely to be grown under conditions that introduce regulatory hurdles, including farming on steeper slopes, with natural streams onsite, and without access to large groundwater aquifers for irrigation. Our findings suggest that failure to allow licensed cannabis farming in traditional agriculture regions has led to a self-fulfilling prophecy wherein cannabis cultivation is largely relegated to environmentally sensitive areas where cultivation activity has an elevated tendency for environmental impacts. • Cannabis cultivation occurs outside conventional agricultural areas on "marginal" land. • Counties with higher incomes and more traditional agriculture issue fewer licenses. • Non-cannabis land users drive cannabis licensing restrictions. • Marginalization of cannabis produces environmental conflict and marginalizes farmers. • Marginal land use is socially and geographically produced. [ABSTRACT FROM AUTHOR]

In the face of recent wildfires across the Western United States, it is essential that we understand both the dynamics that drive the spatial distribution of wildfire, and the major obstacles to modeling the probability of wildfire over space and time. However, it is well documented that the precise relationships of local vegetation, climate, and ignitions, and how they influence fire dynamics, may vary over space and among local climate, vegetation, and land use regimes. This raises questions not only as to the nature of the potentially nonlinear relationships between local conditions and the fire, but also the possibility that the scale at which such models are developed may be critical to their predictive power and to the apparent relationship of local conditions to wildfire. In this study we demonstrate that both local climate–through limitations posed by fuel dryness (CWD) and availability (AET)–and human activity–through housing density, roads, electrical infrastructure, and agriculture, play important roles in determining the annual probabilities of fire throughout California. We also document the importance of previous burn events as potential barriers to fire in some environments, until enough time has passed for vegetation to regenerate sufficiently to sustain subsequent wildfires. We also demonstrate that long-term and short-term climate variations exhibit different effects on annual fire probability, with short-term climate variations primarily impacting fire probability during periods of extreme climate anomaly. Further, we show that, when using nonlinear modeling techniques, broad-scale fire probability models can outperform localized models at predicting annual fire probability. Finally, this study represents a powerful tool for mapping local fire probability across the state of California under a variety of historical climate regimes, which is essential to avoided emissions modeling, carbon accounting, and hazard severity mapping for the application of fire-resistant building codes across the state of California. [ABSTRACT FROM AUTHOR]

The results of ballot referenda have often been used to infer the preferences of voters for various types of policy. However, voters may be influenced by the appearance of competing ballot referenda. We propose a simple theoretical framework for considering the substitutability or complementarity of various land use policies and apply this framework to a novel dataset of 603 land-related municipal ballot measures in California. We find that the appearance of a competing anti-growth measure decreases support for other anti-growth measures, while the appearance of pro-growth measures do not affect the likelihood of passage for anti-growth or pro-growth measures. (JEL R52, D72) [ABSTRACT FROM AUTHOR]

This case study focuses on Fish Friendly Farming, part of a nonprofit organization, the California Land Stewardship Institute. The FFF program is an example of an innovative model for cooperative public-private environmental collaboration and stewardship. The case provides a history of FFF and its ability to create networks and collaborations between parties that typically find it difficult to work together. This case focuses both on sustainability issues related to land and farming, and on challenges related to scaling up a successful nonprofit organization. [ABSTRACT FROM AUTHOR]

Current microbial source tracking techniques that rely on grab samples analyzed by individual endpoint assays are inadequate to explain microbial sources across space and time. Modeling and predicting host sources of microbial contamination could add a useful tool for watershed management. In this study, we tested and evaluated machine learning models to predict the major sources of microbial contamination in a watershed. We examined the relationship between microbial sources, land cover, weather, and hydrologic variables in a watershed in Northern California, United States. Six models, including K-nearest neighbors (KNN), Naïve Bayes, Support vector machine (SVM), simple neural network (NN), Random Forest, and XGBoost, were built to predict major microbial sources using land cover, weather and hydrologic variables. The results showed that these models successfully predicted microbial sources classified into two categories (human and non-human), with the average accuracy ranging from 69% (Naïve Bayes) to 88% (XGBoost). The area under curve (AUC) of the receiver operating characteristic (ROC) illustrated XGBoost had the best performance (average AUC = 0.88), followed by Random Forest (average AUC = 0.84), and KNN (average AUC = 0.74). The importance index obtained from Random Forest indicated that precipitation and temperature were the two most important factors to predict the dominant microbial source. These results suggest that machine learning models, particularly XGBoost, can predict the dominant sources of microbial contamination based on the relationship of microbial contaminants with daily weather and land cover, providing a powerful tool to understand microbial sources in water. [ABSTRACT FROM AUTHOR]

Animal and plant species often face multiple threats simultaneously. We explored the relative impact of three major threats on populations of the endangered San Joaquin kit fox. This species was once widely distributed across the southern San Joaquin Valley, California, USA, but agriculture and urban development have replaced much of its natural habitat. We modeled impacts of climate change, land-use change, and rodenticide exposure on kit fox populations using a spatially explicit, individual-based population model from 2000 to 2050 for the Central Valley, California. Our study indicates that land-use change will likely have the largest impact on kit fox populations. Land development has the potential to decrease populations by approximately 15% under a compact growth scenario in which projected population increases are accommodated within existing urban areas, and 17% under a business-as-usual scenario in which future population growth increases the developed area around urban centers. Plausible scenarios for exposure to pesticides suggest a reduction in kit fox populations by approximately 13%. By contrast, climate change has the potential to ameliorate some of these impacts. Climate-change induced vegetation shifts have the potential to increase total available kit fox habitat and could drive population increases of up to 7%. These vegetation shifts could also reduce movement barriers and create opportunities for hybridization between the endangered San Joaquin kit fox and the more widely distributed desert kit fox, found in the Mojave Desert. In contrast to these beneficial impacts, increasing climate extremes raise the probability of the kit fox population dropping below critical levels. Taken together, these results paint a complex picture of how an at-risk species is likely to respond to multiple threats. [ABSTRACT FROM AUTHOR]

Multispecies wildlife monitoring across large geographical regions is important for effective conservation planning in response to expected impacts from climate change and land use. Unlike many species of birds, mammals, and amphibians which can be efficiently sampled using automated sensors including cameras and sound recorders, reptiles are often much more challenging to detect, in part because of their typically cryptic behavior and generally small body sizes. Although many lizard species are more active during the day which makes them easier to detect using visual encounter surveys, they may be unavailable for sampling during certain periods of the day or year due to their sensitivity to temperature. In recognition of these sampling challenges, we demonstrate application of a recent innovation in distance sampling that adjusts for temporary emigration between repeat survey visits. We used transect surveys to survey lizards at 229 sites throughout the Mojave Desert in California, USA, 2016. We estimated a total population size of 82 million (90% CI: 65–99 million) for the three most common species of lizards across this 66,830 km2 ecoregion. We mapped how density at the 1‐km2 scale was predicted to vary with vegetation cover and human development. We validated these results against independent surveys from the southern portion of our study area. Our methods and results demonstrate how multispecies monitoring programs spanning arid ecoregions can better incorporate information about reptiles. [ABSTRACT FROM AUTHOR]

A recent global trend toward retirement of farmland presents opportunities to reclaim habitat for threatened and endangered species. We examine habitat restoration opportunities in one of the world’s most converted landscapes, California’s San Joaquin Desert (SJD). Despite the presence of 35 threatened and endangered species, agricultural expansion continues to drive habitat loss in the SJD, even as marginal farmland is retired. Over the next decades a combination of factors, including salinization, climate change, and historical groundwater overdraft, are projected to lead to the retirement of more than 2,000 km2 of farmland in the SJD. To promote strategic habitat protection and restoration, we conducted a quantitative assessment of habitat loss and fragmentation, habitat suitability, climatic niche stability, climate change impacts, habitat protection, and reintroduction opportunities for an umbrella species of the SJD, the endangered blunt-nosed leopard lizard (Gambelia sila). We use our suitability models, in conjunction with modern and historical land use maps, to estimate the historical and modern rate of habitat loss to development. The estimated amount of habitat lost since the species became protected under endangered species law in 1967 is greater than the total amount of habitat currently protected through public ownership and conservation easement. We document climatic niche contraction and associated range contraction away from the more mesic margins of the species’ historical distribution, driven by the anthropogenic introduction of exotic grasses and forbs. The impact of exotic species on G. sila range dynamics appears to be still unfolding. Finally, we use NASA fallowed area maps to identify 610 km2 of fallowed or retired agricultural land with high potential to again serve as habitat. We discuss conservation strategies in light of the potential for habitat restoration and multiple drivers of ongoing and historical habitat loss. [ABSTRACT FROM AUTHOR]

The need to balance the goal of environmental protection with that of providing low- and moderate-income housing has become an aggravating and persistent public management problem. The conflict centers around the Issue of housing distribution: who will be housed in environmentally protected areas? The article discusses the recently proposed California Coastal Plan and how it addresses environmental and housing issues. The authors express the concern that although the plan recognizes the housing distribution problem, it fails to offer an adequate solution. The authors suggest a policy solution that would be consistent with the plan's goals. [ABSTRACT FROM AUTHOR]

While many electricity resource mixes can facilitate a zero-carbon electricity system, different pathways can vary significantly in their contribution to environmental impacts. Many current assessments focus on tradeoffs associated with monetary cost, neglecting these wider impacts. Here, electric grid dispatch modeling and electricity mix optimization is combined with data on resource consumption and electricity technology costs to compare five different approaches for developing a 100% zero-carbon electricity system in California: minimum critical metals use, minimum solid construction materials mass, minimum land use, minimum freshwater consumption, and minimum monetary cost under present-day policy goals and constraints. The modeled scenarios show that prioritizing minimum solid construction materials mass in developing such systems also achieve near-minimal monetary cost and land use and did not exhibit the worst performance on either freshwater consumption or critical metals use. In contrast, the strategy that prioritized minimum freshwater consumption exhibited the largest land use and materials use of the five strategies. The minimum monetary cost strategy exhibited near-minimal freshwater consumption, but large land use and the highest demand for critical metals. The modeled monetary unit cost of electricity was lower than the 2030 reference for all zero-carbon electricity system scenarios. The results highlight tradeoffs between contributions to different types of environmental impact in developing a zero-carbon electricity system. Notably, prioritizing certain metrics can result in electricity systems that balance these tradeoffs better than others given the existing suite of zero-carbon options. More broadly, the results show that the planning of zero-carbon electricity systems should more explicitly incorporate non-carbon environmental externalities as co-priorities in their development. • Modeled zero-carbon system development under different non-carbon priorities. • Analyzed the effect of co-priorities on multi-criteria environmental impact & cost. • Co-prioritizing minimum materials throughout yielded lowest multi-criteria impacts. • Prioritizing minimum cost does not necessarily align with minimizing other impacts. • Non-carbon criteria should be considered in zero-carbon electricity planning. [ABSTRACT FROM AUTHOR]

ABSTRACT Bae, H.-K., 2018. The modelling approach for predicting costal pollutions using rainfall distributions over different land use/land cover. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 11–15. Coconut Creek (Florida), ISSN 0749-0208. In this study, a modeling approach using rainfall distribution over different land use/land cover was developed and tested to predict coastal pollutions at the Aliso Beach, California, USA. Rainfall distributions over each land use/land cover of the study area, Aliso Creek Watershed, were calculated to use as input variables for the approach. In addition to rainfall distributions, streamflow and previous total coliform concentrations were also used as input variables. Six-hour. averages of rainfall and streamflow data were used since the approach estimated total coliform concentrations for every Six-hour. The estimations from the previous step, previous total coliform concentration, were used for last input variable if observation data were not available since total coliform concentrations were measured once every three days. Six different model scenarios were tested mainly focusing on rainfall events. As the model scenarios became more complicated, better estimations were shown. The approach showed the possibilities for finer time scale prediction, such as 1 hr. or less time scale or even real-time predictions, since precipitation and streamflow can be available for finer time scale and estimated previous concentrations would be used if observation data were not available. [ABSTRACT FROM AUTHOR]

This study examines sugar beet ( Beta vulgaris L.) as a potential low carbon intensity (CI) fuel feedstock, assuming sugar beet production in California and simulating a facility that exemplifies opportunities for biofuel producers to reduce greenhouse gas emissions, improve fossil-fuel efficiency, and minimize waste. The strategies explored in this study—utilizing byproducts and agricultural residues for renewable process energy and recycling water and nutrients—are not unique to sugar beet-ethanol. As such, the results from this study could be applied to different biofuel pathways to improve greenhouse gas performance. Sugar beets grown in California have unique potential as a biofuel feedstock. Although a mature agricultural product with well-developed supply chains, sugar beet production in California has contracted over recent decades as market demand for sugar production fell. As a consequence, despite their advantages for use in rotation, growers have turned to other crops and a new market for sugar beet products, such as ethanol, is needed before they are again widely planted. California’s Low Carbon Fuel Standard (LCFS) is a fuel-neutral performance standard and one of the first regulations requiring the use of life cycle assessment to evaluate CI for specific fuel pathways. The average CI of ethanol used in California in 2015 is approximately 20% lower than California gasoline blendstock, as assessed under the LCFS. CI results in this study are designed to be comparable with the analyses performed under the LCFS. The CI of sugar beet ethanol determined in this study, 28.5 g CO 2 e/MJ EtOH , excluding indirect land use change (ILUC) emissions, is 44% lower than the 2015 average CI of ethanol (adjusted to exclude ILUC), and 71% lower than gasoline used in California. Commercial production of this modeled pathway could help achieve the greenhouse gas reduction targets of the LCFS as well as the Advanced Biofuel target set by the federal Renewable Fuels Standard. [ABSTRACT FROM AUTHOR]

With growing demand and highly variable inter-annual water supplies, California’s water use future is fraught with uncertainty. Climate change projections, anticipated population growth, and continued agricultural intensification, will likely stress existing water supplies in coming decades. Using a state-and-transition simulation modeling approach, we examine a broad suite of spatially explicit future land use scenarios and their associated county-level water use demand out to 2062. We examined a range of potential water demand futures sampled from a 20-year record of historical (1992–2012) data to develop a suite of potential future land change scenarios, including low/high change scenarios for urbanization and agriculture as well as “lowest of the low” and “highest of the high” anthropogenic use. Future water demand decreased 8.3 billion cubic meters (Bm3) in the lowest of the low scenario and decreased 0.8 Bm3 in the low agriculture scenario. The greatest increased water demand was projected for the highest of the high land use scenario (+9.4 Bm3), high agricultural expansion (+4.6 Bm3), and high urbanization (+2.1 Bm3) scenarios. Overall, these scenarios show agricultural land use decisions will likely drive future demand more than increasing municipal and industrial uses, yet improved efficiencies across all sectors could lead to potential water use savings. Results provide water managers with information on diverging land use and water use futures, based on historical, observed land change trends and water use histories. [ABSTRACT FROM AUTHOR]

Land ownership is one of the primary determinants of how agricultural land is used, and property size has been shown to drive many land use decisions. Land ownership information is also key to understanding food production systems and land fragmentation, and in targeting outreach materials to improve agricultural production and conservation practices. Using a parcel dataset containing all 58 California counties, we describe the characteristics of cropland ownership across California. The largest 5% of properties -- with "property" defned as all parcels owned by a given landowner -- account for 50.6% of California cropland, while the smallest 84% of properties account for 25% of cropland. Cropland ownership inequality (few large properties, many small properties) was greatest in Kings, Kern and Contra Costa counties and lowest in Mendocino, Napa and Santa Clara counties. Of crop types, rice properties had the largest median size, while properties with orchard trees had the smallest median sizes. Cluster analysis of crop mixes revealed that properties with grapes, rice, almonds and alfalfa/ hay tended to be planted to individual crops, while crops such as grains, tomatoes and vegetables were more likely to be mixed within a single property. Analyses of cropland ownership patterns can help researchers prioritize outreach eforts and tailor research to stakeholders' needs. [ABSTRACT FROM AUTHOR]

Agriculture dominates California's San Joaquin Valley with over five million acres of farmland produces 400 different commodities ranging from nuts, tree fruits, vines, and row crops. During dry years agricultural production in the San Joaquin Valley uses about 53% of total applied water in the state. Implementation of California's Sustainable Groundwater Management Act (SGMA) will restrict groundwater pumping, likely reducing irrigated agricultural land use resulting in conversion to alternative land uses. To promote collaborative and inclusive efforts to repurpose agricultural land, California's legislature established a funding program administered by the Department of Conservation, the Multibenefit Land Repurposing Program (MLRP), in 2021. To ensure that land repurposing plans under the MLRP and SGMA represent San Joaquin Valley community needs this paper examines public perceptions of future land uses under SGMA through a phone survey. Respondents (n = 197) were recruited through a stratified random sample of mobile numbers registered within communities in the San Joaquin Valley classified as disadvantaged communities (DACs) (n = 32). Our results show that most respondents were somewhat (33%) or not at all (54%) familiar with SGMA, highlighting the need for outreach efforts to overcome barriers to representation, translation, and education about future water and land use decisions. Survey respondents identified secure water supplies (e.g., groundwater recharge) (35%) and less-water intensive agriculture (27%) as their top land use priorities to address groundwater overdraft under SGMA, indicating that the status quo for land use is preferred to alternative land uses. Preference for maintaining agriculture as primary land use (27%), we correlated with agricultural identity and lack of interest in community or global benefits such as schools and climate change mitigation. The findings from this study underscore the local variability in land use values and the importance to engaging local communities in land use decision-making, especially as they relate to changing current practices toward a more climate-resilient but agriculturally productive future with less land and less water. [Display omitted] • Most respondents were not familiar with the 2014 California Sustainable Groundwater Management Act (SGMA). • Respondents showed a high level of support for groundwater recharge for economic and community well-being. • Secure water supplies and less water-intensive agriculture were perceived as important land use priorities. • The role of agriculture in the local economy and climate change impacts were given higher priority than other land uses. • Outreach efforts need to overcome barriers to representation related to education and language to increase DAC inclusion. [ABSTRACT FROM AUTHOR]

A profession's definition of a concept is a powerful act that illuminates key aspects, while leaving discarded notions in the dark. In 1971, Van Rensselaer Potter first coined the term "bioethics" to advocate for the exploration of medical science and values with the goal of protecting life on earth. But, in the years since, bioethics became solely focused on issues in medicine and health care without recognizing their broader links to the environment. This Note argues that it is shortsighted to view bioethics as divorced from the world outside hospital doors. It further argues that an expanded conceptual model of bioethics is necessary in light of the complexities of contemporary society. Bioethical analysis will be inadequate if the narrow scope of the current definition of bioethics remains unchallenged. If Potter's broader view of bioethics were embraced, bioethical work would include examination of the moral and legal foundations for human health and environmental protection policies. Bioethical analysis could then invite debate on topics like land use and pollution control policies, for example, and not merely on patient care issues within the health care system. [ABSTRACT FROM AUTHOR]

The article looks at Chapter 594 of California Government code proposed by Senators Fran Pavley and Bob Wieckowski to update prior and current laws related to the conservation and management of California's water supply and land use planning processes. It mentions that California Department of Water Resources requested land use agencies to coordinate their planning and development process with water agencies.

Large wildfires in California cause significant socioecological impacts, and half of the federal funds for fire suppression are spent each year in California. Future fire activity is projected to increase with climate change, but predictions are uncertain because humans can modulate or even override climatic effects on fire activity. Here we test the hypothesis that changes in socioecological systems from the Native American to the current period drove shifts in fire activity and modulated fire--climate relationships in the Sierra Nevada. We developed a 415-y record (1600-2015 CE) of fire activity by merging a treering--based record of Sierra Nevada fire history with a 20th-century record based on annual area burned. Large shifts in the fire record corresponded with socioecological change, and not climate change, and socioecological conditions amplified and buffered fire response to climate. Fire activity was highest and fire--climate relationships were strongest after Native American depopulation--following mission establishment (ca. 1775 CE)--reduced the self-limiting effect of Native American burns on fire spread. With the Gold Rush and Euro- American settlement (ca. 1865 CE), fire activity declined, and the strong multidecadal relationship between temperature and fire decayed and then disappeared after implementation of fire suppression (ca. 1904 CE). The amplification and buffering of fire--climate relationships by humans underscores the need for parameterizing thresholds of human- vs. climate-driven fire activity to improve the skill and value of fire--climate models for addressing the increasing fire risk in California. [ABSTRACT FROM AUTHOR]

Ecosystem services support human livelihoods and economies but are declining in many places. Ecosystem service assessments estimate the benefits that nature provides to people and can be used to evaluate trade-offs in impacts and changes resulting from land use decisions. Such assessments can affect the capacity of decision-makers to make sustainable land use decisions, but the actual impact of such projects on decision-maker attitudes is almost entirely unstudied. We addressed this knowledge gap by evaluating the impact of an ecosystem service assessment on decision-makers in California. We asked how decision-makers’ understanding of and attitudes about ecosystem services changed “pre-” and “post-” assessments and between treatment groups where ecosystem services were assessed and a comparison group where ecosystem services were not assessed. Mixed methods included regression models to estimate the treatment effect of the assessment (using a difference-in-differences approach), as well as interviews and direct observations to further understand how decision-makers responded to the assessment. Regression results showed small increases relative to the comparison group in decision-maker understanding of ecosystem services and perceived relevance of ecosystem services to their work. Interviews confirmed that decision-makers learned specific ways that they could use ecosystem services in conservation and development decisions and believed that doing so would improve outcomes. These results demonstrate how ecosystem services assessments can facilitate a conceptual shift in the minds of decision-makers, which is a necessary ingredient for subsequent policy impact. Impact evaluation studies of this type − that estimate a counterfactual and explore rival explanations for observed outcomes − are needed to truly understand whether ecosystem service projects impact decision-makers and, ultimately, produce outcomes for environmental and human well-being. [ABSTRACT FROM AUTHOR]

Understanding the interactions between large-scale atmospheric and oceanic circulation patterns and changes in land cover and land use (LCLU) due to urbanization is a relevant subject in many coastal climates. Recent studies by Lebassi et al. found that the average maximum air temperatures during the summer in two populated California coastal areas decreased at low-elevation areas open to marine air penetration during the period of 1970-2005. This coastal cooling was attributed to an increase in sea-breeze activity. The aims of this work are to better understand the coastal flow patterns and sea-land thermal gradient by improving the land-cover classification scheme in the region using updated airborne remote sensing data and to assess the suitability of the updated regional atmospheric modeling system for representing maritime flows in this region. This study uses high-resolution airborne data from the NASA Hyperspectral Infrared Imager (HyspIRI) mission preparatory flight campaign over Southern California and surface ground stations to compare observations against model estimations. Five new urban land classes were created using broadband albedo derived from the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) sensor and then assimilated into the Weather Research and Forecasting (WRF) Model. The updated model captures the diurnal spatial and temporal sea-breeze patterns in the region. Results show notable improvements of simulated daytime surface temperature and coastal winds using the HyspIRI-derived products in the model against the default land classification, reaffirming the importance of accounting for heterogeneity of urban surface properties. [ABSTRACT FROM AUTHOR]

Biogenic volatile organic compounds (BVOC) participate in reactions that can lead to secondarily formed ozone and particulate matter (PM) impacting air quality and climate. BVOC emissions are important inputs to chemical transport models applied on local to global scales but considerable uncertainty remains in the representation of canopy parameterizations and emission algorithms from different vegetation species. The Biogenic Emission Inventory System (BEIS) has been used to support both scientific and regulatory model assessments for ozone and PM. Here we describe a new version of BEIS which includes updated input vegetation data and canopy model formulation for estimating leaf temperature and vegetation data on estimated BVOC. The Biogenic Emission Landuse Database (BELD) was revised to incorporate land use data from the Moderate Resolution Imaging Spectroradiometer (MODIS) land product and 2006 National Land Cover Database (NLCD) land coverage. Vegetation species data are based on the US Forest Service (USFS) Forest Inventory and Analysis (FIA) version 5.1 for 2002-2013 and US Department of Agriculture (USDA) 2007 census of agriculture data. This update results in generally higher BVOC emissions throughout California compared with the previous version of BEIS. Baseline and updated BVOC emission estimates are used in Community Multiscale Air Quality (CMAQ) Model simulations with 4 km grid resolution and evaluated with measurements of isoprene and monoterpenes taken during multiple field campaigns in northern California. The updated canopy model coupled with improved land use and vegetation representation resulted in better agreement between CMAQ isoprene and monoterpene estimates compared with these observations. [ABSTRACT FROM AUTHOR]

Terrestrial species living in intertidal habitats experience refuge limitation during periods of tidal inundation, which may be exacerbated by seasonal variation in vegetation structure, tidal cycles, and land-use change. Sea-level rise projections indicate the severity of refuge limitation may increase. Artificial habitats that provide escape cover during tidal inundation have been proposed as a temporary solution to alleviate these limitations. We tested for evidence of refuge habitat limitation in a population of endangered California Ridgway's rail ( Rallus obsoletus obsoletus ; hereafter California rail) through use of artificial floating island habitats provided during two winters. Previous studies demonstrated that California rail mortality was especially high during the winter and periods of increased tidal inundation, suggesting that tidal refuge habitat is critical to survival. In our study, California rail regularly used artificial islands during higher tides and daylight hours. When tide levels inundated the marsh plain, use of artificial islands was at least 300 times more frequent than would be expected if California rails used artificial habitats proportional to their availability (0.016%). Probability of use varied among islands, and low levels of use were observed at night. These patterns may result from anti-predator behaviors and heterogeneity in either rail density or availability of natural refuges. Endemic saltmarsh species are increasingly at risk from habitat change resulting from sea-level rise and development of adjacent uplands. Escape cover during tidal inundation may need to be supplemented if species are to survive. Artificial habitats may provide effective short-term mitigation for habitat change and sea-level rise in tidal marsh environments, particularly for conservation-reliant species such as California rails. [ABSTRACT FROM AUTHOR]

Land use change in rangeland ecosystems is pervasive throughout the western United States with widespread ecological, social and economic implications. In California, rangeland habitats have high biodiversity value, provide significant habitat connectivity and form the foundation for a number of ecosystem services. To comprehensively assess the conservation status of these habitats, we analyzed the extent and drivers of habitat loss and the degree of protection against future loss across a 13.5 M ha study area in California. We analyzed rangeland conversion between 1984 and 2008 using time series GIS data and classified resulting land uses with aerial imagery. In total, over 195,000 hectares of rangeland habitats were converted during this period. The majority of conversions were to residential and associated commercial development (49% of the area converted), but agricultural intensification was surprisingly extensive and diverse (40% across six categories). Voluntary enrollment in an agricultural tax incentive program provided widespread protection from residential and commercial conversions across 37% of the remaining rangeland habitat extent (7.5 M ha), though this program did not protect rangeland from conversion to more intensive agricultural uses. Additionally, 24% of the remaining rangeland was protected by private conservation organizations or public agencies through land or easement ownership while 38% had no protection status at all. By developing a spatial method to analyze the drivers of loss and patterns of protection, this study demonstrates a novel approach to prioritize conservation strategies and implementation locations to avert habitat conversion. We propose that this approach can be used in other ecosystem types, and can serve as a regional conservation baseline assessment to focus strategies to effect widespread, cost-effective conservation solutions. [ABSTRACT FROM AUTHOR]

The article focuses on the California Court of Appeal for the Fourth District's decision in case Orange Citizens for Parks & Recreation v. Superior Court that addressed issues that affects public participation in city zoning decisions. Topics discussed include land use designation, the judicial review granted by the California Supreme Court and California Planning and Zoning Law. It mentions the history of zoning in the city of Orange, California.

Highlights: [•] A framework to internalize land use impacts for life cycle costing of energy services is developed. [•] The framework is demonstrated by applying it to a photovoltaic system implementation case study in California. [•] Utility-scale ground mounted PV systems have the least life cycle costs compared to rooftop PV systems. [•] Placing higher values on land use externalities could make ground mounted PV systems less favorable than rooftop systems. [ABSTRACT FROM AUTHOR]

In many parts of the country, hydraulic fracturing has brought energy development onto people's doorsteps. Efforts by local governments to employ traditional land use mechanisms to study and mitigate some of the impacts of these latest intrusions have erupted into battles over the scope of statewide agencies' control. Forgotten in this fray are many renewable energy resources. As a general rule, they are not subject to statewide oversight, and consequently renewable energy providers must navigate the myriad of siting and permitting requirements of local jurisdictions. For several years, scholars have urged more statewide renewable energy siting procedures to level the playing field. California is the national leader in renewable energy deployment, yet its statewide energy commission does not have jurisdiction over the siting of photovoltaic solar or wind energy plants. This article explores when statewide siting is beneficial and when it may be contraindicated, making a case for consolidation of all largescale siting under the purview of California's "superagency," the California Energy Commission. [ABSTRACT FROM AUTHOR]

In this article, the author, who is executive director of Sacramento Valley Conservancy, nonprofit land trust in Sacramento, California. discusses the mission of the organization regarding the permanent changes in land use patterns. Topics discussed include to buy, protect and manage open space lands with proper planning, need to collaborate with the wide variety of partners such as landowners, farmers and ranchers and goals to conserve the plants and wildlife.

Abstract: Land use regression (LUR) models are widely employed in health studies to characterize chronic exposure to air pollution. The LUR is essentially an interpolation technique that employs the pollutant of interest as the dependent variable with proximate land use, traffic, and physical environmental variables used as independent predictors. Two major limitations with this method have not been addressed: (1) variable selection in the model building process, and (2) dealing with unbalanced repeated measures. In this paper, we address these issues with a modeling framework that implements the deletion/substitution/addition (DSA) machine learning algorithm that uses a generalized linear model to average over unbalanced temporal observations. Models were derived for fine particulate matter with aerodynamic diameter of 2.5 microns or less (PM2.5) and nitrogen dioxide (NO2) using monthly observations. We used 4119 observations at 108 sites and 15,301 observations at 138 sites for PM2.5 and NO2, respectively. We derived models with good predictive capacity (cross-validated-R 2 values were 0.65 and 0.71 for PM2.5 and NO2, respectively). By addressing these two shortcomings in current approaches to LUR modeling, we have developed a framework that minimizes arbitrary decisions during the model selection process. We have also demonstrated how to integrate temporally unbalanced data in a theoretically sound manner. These developments could have widespread applicability for future LUR modeling efforts. [Copyright &y& Elsevier]

Abstract: Participatory adaptive management is widely promoted as the new paradigm in public lands management. It is grounded in two underlying principles – that management experiments and diverse sources of information should be used to continually refine management in complex ecological systems, and that the public must be included throughout the adaptive management process. Access to scientific results and exchange of information is at the core of both of these principles. The recent proliferation of Internet communities and web-based participation tools raises the question of how the Internet might help facilitate information exchange in participatory adaptive management. Using a case study approach, the role of web technologies in facilitating the flow of transparent and useful information was examined in a participatory adaptive management project focused on Forest Service vegetation management treatments in California''s Sierra Nevada. Three evaluation methods were used: analysis of web usage and content, a survey of active participants, and a review of comments posted to the project website. Results suggest that the web played an important role throughout the adaptive management cycle by supporting communication through disseminating information to the public and increasing the transparency of the scientific process. The web played a small, but important role in public consultation, by providing a forum for targeted questions and feedback from the public. Internet technology did not actively support the two-way flow of information necessary for mutual learning. Web technology complements face-to-face interactions and public meetings, rather than replacing them. [Copyright &y& Elsevier]

Anticoagulant rodenticide (AR) poisoning has emerged as a significant concern for conservation and management of nontarget wildlife. The purpose for these toxicants is to suppress pest populations in agricultural or urban settings. The potential of direct and indirect exposures and illicit use of ARs on public and community forest lands have recently raised concern for fishers (Martes pennanti), a candidate for listing under the federal Endangered Species Act in the Pacific states. In an investigation of threats to fisher population persistence in the two isolated California populations, we investigate the magnitude of this previously undocumented threat to fishers, we tested 58 carcasses for the presence and quantification of ARs, conducted spatial analysis of exposed fishers in an effort to identify potential point sources of AR, and identified fishers that died directly due to AR poisoning. We found 46 of 58 (79%) fishers exposed to an AR with 96% of those individuals having been exposed to one or more second-generation AR compounds. No spatial clustering of AR exposure was detected and the spatial distribution of exposure suggests that AR contamination is widespread within the fisher's range in California, which encompasses mostly public forest and park lands Additionally, we diagnosed four fisher deaths, including a lactating female, that were directly attributed to AR toxicosis and documented the first neonatal or milk transfer of an AR to an altricial fisher kit. These ARs, which some are acutely toxic, pose both a direct mortality or fitness risk to fishers, and a significant indirect risk to these isolated populations. Future research should be directed towards investigating risks to prey populations fishers are dependent on, exposure in other rare forest carnivores, and potential AR point sources such as illegal marijuana cultivation in the range of fishers on California public lands. [ABSTRACT FROM AUTHOR]

Abstract: Over half of the United States is privately owned. Improving environmental sustainability requires that the scientific and management communities provide effective outreach to the many landowners making decisions about land use and management practices on these lands. We surveyed California forest and rangeland owners in ten counties throughout the state to assess the impact of existing outreach and identify gaps in information distribution and content. Although a number of organizations provide land management advice highly-ranked by landowners, no individual organization currently reaches more than 30% of forest and rangeland owners, and these groups together reach less than 60% of landowners. The lowest ranked advice came from wildlife and land management agencies, whereas the highest ranked advice came from private consultants and advisory organizations. The ecosystem services provided by forests and rangelands are strongly influenced by conservation scale, and this appears to be recognized in current outreach efforts. Owners of large properties (>200 ha) were substantially more likely to have received land management advice than smaller-sized properties, and from a broader group of organizations. As ownerships become increasingly fragmented, outreach focus and methods will need to shift to more effectively target the owners of smaller properties. On the other hand, some major outreach goals, such as conservation of wildlife, ranchland, or agricultural communities, will continue to rely on effective outreach to owners of larger properties. [Copyright &y& Elsevier]

California fire regimes have been altered from those that occurred prior to Euro-American settlement, and are predicted to continue to change as global climates warm. Inclusion of fire as a landscape-level process is considered essential to successful ecological restoration in many ecosystems, and presettlement fire regimes provide foundational information for restoration or "realignment" of ecosystems as climate change and land use changes progress. The objective of our study was to provide an up-to-date, comprehensive summary of presettlement fire frequency estimates for California ecosystems dominated by woody plants, and to supply the basis for fire return interval departure (FRID) mapping and analysis in California. Using the LANDFIRE Biophysical Settings (BpS) vegetation-fire regime types as a framework, we used literature review and the outcomes of regional expert workshops to develop twenty-eight presettlement fire regime (PFR) groups based on similarity of their relationships with fire. We then conducted an exhaustive review of the published and unpublished literature pertaining to fire return intervals (FRIs) observed prior to significant Euro-American settlement in the twenty-eight PFRs, and summarized the values to provide a single estimate of the mean, median, mean minimum, and mean maximum FRI for each PFR. Much variability was evident among PFRs, with mean FRIs ranging from 11 yr to 610 yr, and median FRIs ranging from 7 yr to 610 yr; mean minimum FRIs ranged from 5 yr to 190 yr, and mean maximum FRIs ranged from 40 yr to 1440 yr. There was also high variability within many PFRs, and differences between minimum and maximum FRIs ranged from 32 yr to 1324 yr. Generally, median FRIs were lowest for productive drier forests such as yellow pine, dry and moist mixed conifer, and oak woodland (7 yr, 9 yr, 12 yr, and 12 yr, respectively). Median FRIs were highest for less productive woodlands such as pinyon-juniper (94 yr), high elevation types such as subalpine forest (132 yr), very dry types such as desert mixed shrub (610 yr), and productive moist forests such as spruce-hemlock (275 yr mean FRI). Our summary of California's presettlement fire regimes should be a useful reference for scientists and resource managers, whether they are seeking a general estimate of the central tendency and variability of FRIs in a broadly defined vegetation type, background information for a planned restoration project or a mechanistic model of vegetation-fire interactions, or a list of literature pertaining to a specific vegetation type or geographic location. [ABSTRACT FROM AUTHOR]

A regional atmosphere model [Weather Research and Forecasting model version 3 (WRF3)] and a land surface model [Community Land Model, version 3.5 (CLM3.5)] were coupled to study the interactions between the atmosphere and possible future California land-cover changes. The impact was evaluated on California''s climate of changes in natural vegetation under climate change and of intentional afforestation. The ability of WRF3 to simulate California''s climate was assessed by comparing simulations by WRF3--CLM3.5 and WRF3--Noah to observations from 1982 to 1991. Using WRF3--CLM3.5, the authors performed six 13-yr experiments using historical and future large-scale climate boundary conditions from the Geophysical Fluid Dynamics Laboratory Climate Model version 2.1 (GFDL CM2.1). The land-cover scenarios included historical and future natural vegetation from the Mapped Atmosphere-Plant-Soil System-Century 1 (MC1) dynamic vegetation model, in addition to a future 8-million-ha California afforestation scenario. Natural vegetation changes alone caused summer daily-mean 2-m air temperature changes of −−0.7°° to ++1°°C in regions without persistent snow cover, depending on the location and the type of vegetation change. Vegetation temperature changes were much larger than the 2-m air temperature changes because of the finescale spatial heterogeneity of the imposed vegetation change. Up to 30% of the magnitude of the summer daily-mean 2-m air temperature increase and 70% of the magnitude of the 1600 local time (LT) vegetation temperature increase projected under future climate change were attributable to the climate-driven shift in land cover. The authors projected that afforestation could cause local 0.2°°--1.2°°C reductions in summer daily-mean 2-m air temperature and 2.0°°--3.7°°C reductions in 1600 LT vegetation temperature for snow-free regions, primarily because of increased evapotranspiration. Because some of these temperature changes are of comparable magnitude to those projected under climate change this century, projections of climate and vegetation change in this region need to consider these climate--vegetation interactions. [ABSTRACT FROM AUTHOR]

In this study, the influence of land use change and irrigation in the California Central Valley is quantified using the Pennsylvania State University/National Center for Atmospheric Research fifth generation Mesoscale Model (MM5) coupled with the Community Land Model version 3 (CLM3). The simulations were forced with modern-day and presettlement land use types at 30-km spatial resolution for the period 1 October 1995 to 30 September 1996. This study shows that land use change has significantly altered the structure of the planetary boundary layer (PBL) that affects near-surface temperature. In contrast, many land-use change studies indicate that albedo and evapotranspiration variations are the key processes influencing climate at local-to-regional scales. Our modeling results show that modern-day daily maximum near-surface air temperature (Tmax) has decreased due to agricultural expansion since presettlement. This decrease is caused by weaker sensible heat flux resulting from the lower surface roughness lengths associated with modern-day crops. The lower roughness lengths in the Central Valley also result in stronger winds that lead to a higher PBL. The higher PBL produces stronger sensible heat flux, causing nighttime warming. In addition to land use change, cropland irrigation has also affected hydroclimate processes within the California Central Valley. We generated a 10-member MM5-CLM3 ensemble simulation, where each ensemble member was forced by a fixed volumetric soil water content (SWC) between 3% and 30%, at 3% intervals, over the irrigated areas during a spring-summer growing season, 1 March to 31 August 1996. The results show that irrigation lowers the modern-day cropland surface temperature. Daytime cooling is produced by irrigation-related evaporation enhancement. This increased evaporation also dominates the nighttime surface cooling process. Surface cooling and the resulting weaker sensible heat flux further lower the near-surface air temperature. Thus, irrigation strengthens the daytime near-surface air temperature reduction that is caused by land use change, and a similar temperature change is seen for observations over irrigated cropland. Based on our modeling results, the nighttime near-surface warming induced by land use change is alleviated by low-intensity irrigation (17% < SWC < 19%), but such warming completely reverses to a cooling effect under high-intensity irrigation (SWC > 19%). The land use changes discussed in this study are commonly observed in many regions of the world, and the physical processes identified here can be used to better understand temperature variations over other areas with similar land cover changes. [ABSTRACT FROM AUTHOR]

Abstract: Background: Polycyclic aromatic hydrocarbons (PAHs) are generated as a byproduct of combustion, and are associated with respiratory symptoms and increased risk of asthma attacks. Objectives: To assign daily, outdoor exposures to participants in the Fresno Asthmatic Children’s Environment Study (FACES) using land use regression models for the sum of 4-, 5- and 6-ring PAHs (PAH456). Methods: PAH data were collected daily at the EPA Supersite in Fresno, CA from 10/2000 through 2/2007. From 2/2002 to 2/2003, intensive air pollution sampling was conducted at 83 homes of participants in the FACES study. These measurement data were combined with meteorological data, source data, and other spatial variables to form a land use regression model to assign daily exposure at all FACES homes for all years of the study (2001–2008). Results: The model for daily, outdoor residential PAH456 concentrations accounted for 80% of the between-home variability and 18% of the within-home variability. Both temporal and spatial variables were significant in the model. Traffic characteristics and home heating fuel were the main spatial explanatory variables. Conclusions: Because spatial and temporal distributions of PAHs vary on an intra-urban scale, the location of the child’s home within the urban setting plays an important role in the level of exposure that each child has to PAHs. [Copyright &y& Elsevier]

We present the first comprehensive multi-temporal analysis of land-cover change for California across its major ecological regions and primary land-cover types. Recently completed satellite-based estimates of land-cover and land-use change information for large portions of the United States allow for consistent measurement and comparison across heterogeneous landscapes. Landsat data were employed within a pure-panel stratified one-stage cluster sample to estimate and characterize land-cover change for 1973-2000. Results indicate anthropogenic and natural disturbances, such as forest cutting and fire, were the dominant changes, followed by large fluctuations between agriculture and rangelands. Contrary to common perception, agriculture remained relatively stable over the 27-year period with an estimated loss of 1.0% of agricultural land. The largest net declines occurred in the grasslands/shrubs class at 5,131 km and forest class at 4,722 km. Developed lands increased by 37.6%, composing an estimated 4.2% of the state's land cover by 2000. [ABSTRACT FROM AUTHOR]

State mandates and guidelines significantly influence local land use planning; however few studies have been conducted to empirically detect the gaps in sustainable environmental planning between the state and local jurisdictions. This paper analyses the California Governor's Environmental Goals and Policy Report (EGPR) and 116 local comprehensive land use plans to develop a set of measurable indicators to detect gaps in local planning efforts to incorporate state goals and policies. Descriptive results indicate that the local jurisdictions reached approximately half of the state's sustainable environmental planning goals. The major gaps existed in some region-wide, global-wide, long-term, cumulative, and strategically critical environmental elements. Regression results further highlight the major factors that significantly influenced local jurisdictions' environmental planning abilities. Six policy recommendations are provided to reduce these gaps. [ABSTRACT FROM AUTHOR]