D. Richard Cameron

Landscape-scale indicators of biodiversity's vulnerability to climate change

Climate change will increase the vulnerability of species across the globe to population loss and extinction. In order to develop conservation strategies to facilitate adaptation to this change, managers must understand the vulnerability of the habitats and species they are trying to manage. For most biodiversity managers, conducting vulnerability assessments for all of the species they manage would be prohibitively costly, time consuming, and potentially misleading since some data required does not yet exist. We present a rapid and cost-effective method to estimate the vulnerability of biodiversity to climate change impacts across broad areas using landscape-scale indicators. While this method does not replace species-specific vulnerability assessments, it allows biodiversity managers to focus analysis on the species likely to be most vulnerable and identify the categories of conservation strategies for implementation to reduce biodiversitys vulnerability to climate change. We applied this method to California, USA to map the portions of the state where biodiversity managers should focus on minimizing current threats to biodiversity (9%), reducing constraints to adaptation (28%), reducing exposure to climatic changes (24%), and implementing all three (9%). In 18% of the state, estimated vulnerability is low so continuing current strategies and monitoring for changes is likely sufficient, while in 12% of the state, vulnerability is so high that biodiversity managers may have to reassess current conservation goals. In combination with species-specific vulnerability assessments or alone, mapping vulnerability based on landscape-scale indicators will allow managers to take an essential step toward implementing conservation strategies to help imperiled species adapt to climate change.

An Approach to Enhance the Conservation-Compatibility of Solar Energy Development

The rapid pace of climate change poses a major threat to biodiversity. Utility-scale renewable energy development (>1 MW capacity) is a key strategy to reduce greenhouse gas emissions, but development of those facilities also can have adverse effects on biodiversity. Here, we examine the synergy between renewable energy generation goals and those for biodiversity conservation in the 13 M ha Mojave Desert of the southwestern USA. We integrated spatial data on biodiversity conservation value, solar energy potential, and land surface slope angle (a key determinant of development feasibility) and found there to be sufficient area to meet renewable energy goals without developing on lands of relatively high conservation value. Indeed, we found nearly 200,000 ha of lower conservation value land below the most restrictive slope angle (<1%); that area could meet the state of California’s current 33% renewable energy goal 1.8 times over. We found over 740,000 ha below the highest slope angle (<5%) – an area that can meet California’s renewable energy goal seven times over. Our analysis also suggests that the supply of high quality habitat on private land may be insufficient to mitigate impacts from future solar projects, so enhancing public land management may need to be considered among the options to offset such impacts. Using the approach presented here, planners could reduce development impacts on areas of higher conservation value, and so reduce trade-offs between converting to a green energy economy and conserving biodiversity.

Identifying habitat conservation priorities and gaps for migratory shorebirds and waterfowl in California

Conservation of migratory shorebirds and waterfowl presents unique challenges due to extensive historic loss of wetland habitats, and current reliance on managed landscapes for wintering and migratory passage. We developed a spatially-explicit approach to estimate potential shorebird and waterfowl densities in California by integrating mapped habitat layers and statewide bird survey data with expert-based habitat rankings. Using these density estimates as inputs, we used the Marxan site-selection program to identify priority shorebird and waterfowl areas at the ecoregional level. We identified 3.7 million ha of habitat for shorebirds and waterfowl, of which 1.4 million ha would be required to conserve 50% of wintering populations. To achieve a conservation goal of 75%, more than twice as much habitat (3.1 million ha) would be necessary. Agricultural habitats comprised a substantial portion of priority areas, especially at the 75% level, suggesting that under current management conditions, large areas of agricultural land, much of it formerly wetland, are needed to provide the habitat availability and landscape connectivity required by shorebird and waterfowl populations. These habitats were found to be largely lacking recognized conservation status in California (96% un-conserved), with only slightly higher levels of conservation for priority shorebird and waterfowl areas. Freshwater habitats, including wetlands and ponds, were also found to have low levels of conservation (67% un-conserved), although priority shorebird and waterfowl areas had somewhat higher levels of conservation than the state as a whole. Conserving migratory waterfowl and shorebirds will require a diversity of conservation strategies executed at a variety of scales. Our modeled results are complementary with other approaches and can help prioritize areas for protection, restoration and other actions. Traditional habitat protection strategies such as conservation easements and fee acquisitions may be of limited utility for protecting and managing significant areas of agricultural lands. Instead, conservation strategies focused on incentive-based programs to support wildlife friendly management practices in agricultural settings may have greater utility and conservation effectiveness.

Future land-use related water demand in California

Water shortages in California are a growing concern amidst ongoing drought, earlier spring snowmelt, projected future climate warming, and currently mandated water use restrictions. Increases in population and land use in coming decades will place additional pressure on already limited available water supplies. We used a state-and-transition simulation model to project future changes in developed (municipal and industrial) and agricultural land use to estimate associated water use demand from 2012 to 2062. Under current efficiency rates, total water use was projected to increase 1.8 billion cubic meters (+4.1%) driven primarily by urbanization and shifts to more water intensive crops. Only if currently mandated 25% reductions in municipal water use are continuously implemented would water demand in 2062 balance to water use levels in 2012. This is the first modeling effort of its kind to examine regional land-use related water demand incorporating historical trends of both developed and agricultural land uses.

Economic Costs of Achieving Current Conservation Goals in the Future as Climate Changes

Conservation of biologically diverse regions has thus far been accomplished largely through the establishment and maintenance of protected areas. Climate change is expected to shift climate space of many species outside existing reserve boundaries. We used climate-envelope models to examine shifts in climate space of 11 species that are representative of the Mount Hamilton Project area (MHPA) (California, U.S.A.), which includes areas within Alameda, Santa Clara, San Joaquin, Stanislaus, Merced, and San Benito counties and is in the states Central Coast ecoregion. We used Marxan site-selection software to determine the minimum area required as climate changes to achieve a baseline conservation goal equal to 80% of existing climate space for all species in the MHPA through 2050 and 2100. Additionally, we assessed the costs associated with use of existing conservation strategies (land acquisition and management actions such as species translocation, monitoring, and captive breeding) necessary to meet current species-conservation goals as climate changes. Meeting conservation goals as climate changes through 2050 required an additional 256,000 ha (332%) of protected area, primarily to the south and west of the MHPA. Through 2050 the total cost of land acquisition and management was estimated at US

Ecosystem management and land conservation can substantially contribute to California’s climate mitigation goals

1.67-1.79 billion, or 139-149% of the cost of achieving the same conservation goals with no climate change. To maintain 80% of climate space through 2100 required nearly 380,000 additional hectares that would cost

Making habitat connectivity a reality: Habitat Connectivity

2.46-2.62 billion, or 209-219% of the cost of achieving the same conservation goals with no climate change. Furthermore, maintaining 80% of existing climate space within California for 27% of the focal species was not possible by 2100 because climate space for these species did not exist in the state. The high costs of conserving species as the climate changes-that we found in an assessment of one conservation project-highlights the need for tools that will aid in iterative goal setting given the uncertainty of the effects of climate change and adaptive management that includes new conservation strategies and consideration of the long-term economic costs of conservation.

Mediterranean California’s water use future under multiple scenarios of developed and agricultural land use change

Significance Combatting climate change will require using all available tools, especially those that contribute to other societal and economic goals, such as natural resource protection and energy security. Conserving and managing natural and agricultural lands to retain and absorb greenhouse gasses (GHGs) are tools that have not been widely integrated into climate policy. Our analysis provides a quantification of potential climate benefits from multiple land-based activities for a jurisdiction with an emissions reduction target (up to 13.3% of the cumulative reductions needed to meet the 2050 target, or nearly three-fourths of a billion metric tons of GHGs). This approach provides a model that other jurisdictions can use to evaluate emissions reductions that might be achieved from conserving and restoring natural lands. Modeling efforts focused on future greenhouse gas (GHG) emissions from energy and other sectors in California have shown varying capacities to meet the emissions reduction targets established by the state. These efforts have not included potential reductions from changes in ecosystem management, restoration, and conservation. We examine the scale of contributions from selected activities in natural and agricultural lands and assess the degree to which these actions could help the state achieve its 2030 and 2050 climate mitigation goals under alternative implementation scenarios. By 2030, an Ambitious implementation scenario could contribute as much as 147 MMTCO2e or 17.4% of the cumulative reductions needed to meet the state’s 2030 goal, greater than the individual projected contributions of four other economic sectors, including those from the industrial and agricultural sectors. On an annual basis, the Ambitious scenario could result in reductions as high as 17.9 MMTCO2e⋅y−1 or 13.4% of the state’s 2030 reduction goal. Most reductions come from changes in forest management (61% of 2050 projected cumulative reductions under the Ambitious scenario), followed by reforestation (14%), avoided conversion (11%), compost amendments to grasslands (9%), and wetland and grassland restoration (5%). Implementation of a range of land-based emissions reduction activities can materially contribute to one of the most ambitious mitigation targets globally. This study provides a flexible, dynamic framework for estimating the reductions achievable through land conservation, ecological restoration, and changes in management regimes.

Erratum to: The impact of climate change on California's ecosystem services

Although a plethora of habitat-connectivity plans exists, protecting and restoring connectivity through on-the-ground action has been slow. We identified challenges to and opportunities for connectivity conservation through a literature review of project implementation, a workshop with scientists and conservation practitioners, 3 case studies of connectivity projects, and interviews with conservation professionals. Connectivity challenges and solutions tended to be context specific, dependent on land-ownership patterns, socioeconomic factors, and the policy framework. Successful connectivity implementation tended to be associated with development and promotion of a common vision among diverse sets of stakeholders, including nontraditional conservation actors, such as water districts and recreation departments, and with communication with partners and the public. Other factors that lead to successful implementation included undertaking empirical studies to prioritize and validate corridors and the identification of related co-benefits of corridor projects. Engaging partners involved in land management and planning, such as nongovernmental conservation organizations, public agencies, and private landowners, is critical to effective strategy implementation. A clear regulatory framework, including unambiguous connectivity conservation mandates, would increase public resource allocation, and incentive programs are needed to promote private sector engagement. Connectivity conservation must move more rapidly from planning to implementation. We provide an evidence-based solution composed of key elements for successful on-the-ground connectivity implementation. We identified the social processes necessary to advance habitat connectivity for biodiversity conservation and resilient landscapes under climate change.

Modeling residential development in California from 2000 to 2050: Integrating wildfire risk, wildland and agricultural encroachment

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.