Photovoltaic solar farms in California: can we have renewable electricity and our species, too?

Photovoltaic solar power generating facilities are proliferating rapidly in California and elsewhere. While this trend is welcomed for many reasons (e.g., reducing greenhouse gas emissions), these facilities also can have profound environmental impacts, particularly to local species populations. These impacts become more significant when species of conservation concern are affected. In the San Joaquin Desert region in central California, a number of conservation measures have been routinely implemented on solar facilities, and these measures have facilitated continued use of the facilities by a number of species of conservation concern. Some of the more significant measures include permeable security fences, vegetation management, movement corridors, avoiding critical features such as dens and burrows, and vehicle speed limits. Detailed studies have been conducted on San Joaquin kit foxes (Vulpes macrotis mutica) using solar facilities in the San Joaquin Desert. Demographic and ecological attributes of foxes are similar between foxes using the facilities and foxes on nearby reference sites, and values for foxes on solar sites are within the ranges of values for foxes reported from sites within core population areas. Facilitated by the conservation measures, kit foxes are using at least six facilities in the San Joaquin Desert as are a variety of other species of conservation concern. This successful model also potentially could be adapted to other ecosystems and applied to facilities in regions outside of the San Joaquin Desert, such as the Mojave Desert. Determining whether species in other regions can use photovoltaic solar facilities and identifying the most efficacious conservation measures will require time and testing, and these efforts would benefit from collaborative efforts among landowners, solar developers, natural resources agencies, researchers, and others. The San Joaquin Desert facilities and a recent demonstration facility in the Mojave Desert provide strong evidence that solar facilities can be constructed and operated in a manner that also accommodates continued use of the facilities by some species of conservation concern.

The case for case studies: A new approach to evaluating the effectiveness of livestock protection tools

Livestock operations in California face livestock losses due to a range of carnivore species. Simultaneously, there is an increased call to reduce the use of lethal predator control methods and replace them with nonlethal methods. Livestock guardian dogs (Canis lupus familiaris) are one such nonlethal livestock protection tool (LPT), yet research is still lacking on the factors and situations that impact their effectiveness. Using three case studies, we demonstrate the value of objective analyses that explicitly address the inherent differences in ranch management, environment, and surrounding land uses in examining livestock guardian dogs as an LPT. We used semi-structured questionnaire surveys of livestock operators to collect information on effectiveness, behavior, and producer satisfaction of LGDs protecting poultry (Gallus gallus domesticus), calves (Bovus taurus), and sheep (Ovis aries) on private and public land and in conjunction with a variety of other livestock protection tools. We aimed to address all aspects related to the use of LGDs as a means of informing livestock operators’ decisions on whether LGDs are an appropriate tool for a particular operation. The case studies demonstrated the complexities involved in applying LGDs as a LPT within the context of a livestock operation. In two of the three case studies, LGDs did not entirely eliminate livestock losses yet operator satisfaction remained high.

Factors influencing the abundance of wintering western snowy plovers at Crown Memorial State Beach

Survival during the nonbreeding season, when mortality from food shortages and raptor predation is highest, influences shorebird population growth. These selection pressures, as well as anthropogenic influences, can shape wintering shorebird habitat use patterns. The western snowy plover (Charadrius alexandrinus nivosus) is a small shorebird that uses sand-spits, dune-backed beaches, open areas around estuaries for foraging and roosting. The Pacific Coast population of western snowy plovers is listed as a federally threatened species and a California Species of Special Concern. Previous studies suggest humans, dogs and corvids are sources of disturbance to plovers on public beaches. During 2014 to 2019, these disturbance factors were examined at Robert W. Crown Memorial State Beach in Alameda, California. In decreasing order of impact, the beach using public, corvids, and dogs were found to be the major stressors to over wintering plovers. Both the public and corvids respectively, resulted in disturbance and avoidance behaviors by plovers nearly 40% of the time. In 2015, the District created the Plover Protection Zone (PPZ) by installing symbolic fencing, signage, and establishing a volunteer team to monitor plovers and educate the public. In 2016, the potential prey abundance within the plover protection zone and areas directly north and south were examined using core samples and sticky traps. Statistical analysis showed a significant difference in the amount of macro-invertebrate prey available in the area used by the plovers as compared to other locations. Habitat choice and prey availability are vital to wintering shorebird. During this study, the wintering population of western snowy plovers increased from six to over 54 individuals.

Conflict, coexistence, or both? Cougar habitat selection, prey composition, and mortality in a multiple-use landscape

Western North America is experiencing remarkable human population growth and land-use change. Irrigation and associated cultivation have led to colonization of urban-wildland interface (UWI) environments by mule deer (Odocoileus hemionus), and consequently, cougars (Puma concolor). In the wake of these changes, human-wildlife conflicts have increased in tandem with questions about long-term species conservation. To address these concerns, we fit 79 cougars with radio-telemetry collars in the Oquirrh Mountains near Salt Lake City, Utah (2002–2010). Our goal was to evaluate variation in cougar habitat selection, diet, and cause-specific mortality in a landscape dominated by urban, military, and industrial activities. We used radio-telemetry data in concert with Resource Selection Functions to address three hypotheses: (1) that cougars would select wildland over UWI land-uses; (2) prey composition would reflect differences in land-use; and (3) mortality would be predominantly human-caused. Cougars largely selected wildland habitats associated with seasonal mule deer presence, but contrary to expectation, they also selected habitats closer to urban and mined areas. Prey composition in the UWI did not differ from wildland habitats. Domestic ungulates represented only 2% of 540 recovered prey items and were found primarily in wildlands. Native ungulates comprised > 90% of the total kill, irrespective of season or land-use, suggesting that use of UWI habitats was linked to mule deer presence. Cougar mortality was disproportionately due to natural causes in wildlands, but individuals that died of human causes in UWI habitats were more likely to be inexperienced hunters, supporting young kittens, or compromised by physical handicaps. In general, presence of mule deer was the key predictor of cougar habitat use, even in this highly disturbed, anthropogenically altered landscape. As such, management designed to reduce conflict and ensure conservation will need to focus on urban deer, land-use planning, and targeted education campaigns to reduce food subsidies.

Environmental values of California winegrape growers and the use of barn owl nest boxes as a tool for integrated pest management

Synthetic pesticides from agriculture pose threats to biodiversity, and the adoption of alternative pest management is vital to meet rising crop demands while protecting native species. For example, the use of nest boxes for barn owls (Tyto furcata and T. alba) may help control rodent pests and reduce the use of rodenticides. However, the environmental perceptions of farmers and how receptive they are to alternative pest management practices remains uncertain. Traditionally, agricultural policies and programs have focused largely on the economic self-interest of farmers, but these narrow approaches have proven insufficient to describe and predict conservation behaviors, and the study of environmental value orientations (EVOs) may better explain farmers’ adoption of novel wildlife-friendly practices. The study of EVOs can help identify people as “mutualists”, meaning those who value the environment for its own sake, and “utilitarians,” meaning those who value the environment for the services it can provide. We surveyed 71 California winegrape growers in order to better understand how their underlying environmental values relate to the use of barn owl boxes and other sustainable practices. Overall, most winegrape growers had mutualist value orientations (64%). However, there was a disconnect between the use of barn owl boxes and EVOs, with most respondents (80%) reporting the use of owl boxes regardless of underlying values. This opens the door for future research to examine whether this is true of other wildlife-friendly farming practices.

Thematic and hotspot analysis of human-elk conflicts statewide in California

Human-wildlife conflicts are an important factor for consideration in wildlife management at urban-wildland interfaces. Effective and adaptive management of human-wildlife conflicts is needed to promote tolerance and coexistence of humans and wildlife. Anecdotal reports suggest a recent spike in human-elk conflicts in California, yet there has not been a systematic analysis of human-elk conflicts in the state. To better understand human-elk conflicts in California, we conducted thematic analysis of human-elk conflicts reported in the California Department of Fish and Wildlife’s Wildlife Incident Reporting (WIR) system. We also conducted a hotspot analysis using locations of human-elk conflicts reported in the WIR system and evaluated reports for principles of adaptive management. The WIR system contained n = 89 reports for elk and n = 78 of these described conflicts with elk. Overall, property damage (including crop damage) was the most common type of human-elk conflict reported, occurring in 69% of reports (n = 54/78), followed by non-competitive conflict with domestic animals (13%), competition with domestic livestock (12%), and habituation to humans (24%). We identified three hotspots of human-elk conflict in California in Del Norte, Kern, and San Luis Obispo counties. All incidents of human-elk conflict reported in the WIR system included at least one principle of adaptive management. We recommend modifications to the WIR system and interactions with property owners and stakeholders to enhance and facilitate adaptive management of human-elk conflicts in California.

Relocation of habituated black bears in the Klamath Mountains of California: an adaptive management case study

Black bear (Ursus americanus) populations in California have increased in abundance and distribution despite rising trends in the urban encroachment of wildlands. As human-black bear conflicts increase, opportunities to study the relocation of black bears in an adaptive management setting are important for improving the management of this highprofile species. Habituated black bears, some tamed and made tractable through human-controlled food conditioning, were relocated to a remote region of the Klamath Mountains to analyze home range use, survival, return rates, and mortality. Relocated black bears with known outcomes demonstrated an 80% return rate, with 55% not surviving beyond five months. Female bears established home ranges significantly larger than males, and may suggest an enhanced maternal instinct in search of similar nutritional conditions prior to relocation. This study showed that the relocation of food-conditioned black bears resulted in high return rates, poor survival, and risk to public safety.

An innovative temporary escape ramp for deer and other wildlife

Concrete-lined water conveyance canals can be a significant source of mortality for ungulates and other wildlife, which can drown or become entrapped. Various types of wildlife escape structures have been deployed in canals with limited success. From 2011 to 2018, we used camera traps to monitor mule deer (Odocoileus hemionus) use of three different temporary wildlife escape structure designs with the goal of developing an effective escape structure for fawns. We monitored three to five locations at a hydroelectric water conveyance canal, operated by Pacific Gas and Electric Company in the foothills of Central California on the Sierra National Forest, in which trapped fawns had been detected previously during the maintenance period when the canal was dry. Mule deer activity and ramp use varied by year. During the monitoring period, deer were detected in the canal in all years except 2016 and 2017. Fawns and adults used the temporary escape structures to exit the canal in four of these years and 50% of mule deer detections showed ramp use overall. No deer were detected using the escape structures until jute netting and debris were added to the surface of the escape ramps in the third monitoring year. Prior to this modification, fawns were detected trapped in the canal investigating the ramps, but not using them to exit the canal. Deer may be more likely to utilize ramps covered with materials that mimic native ground cover. Seven other wildlife species were detected entering and exiting using the ramps with a general increase in use over years. Our temporary escape ramp design for small canals, when dry, appears to be novel and may be applicable in other areas. When compared to fencing or covering the canal, it is a relatively low-cost solution to reduce animal entrapment.

Coyote Management Plans and Wildlife Watch: implications for community coaching approach to public outreach in southern California

The majority of residents in southern California live in urban areas. Therefore, working with cities to promote tolerance and coexistence with urban wildlife is crucial to the conservation and management of native species. Human conflicts with coyotes (Canis latrans) illustrate the importance of incorporating the social sciences, particularly knowledge of human behavior, communication, and education, in a coyote management strategy. Here, we review 199 cities across southern California to determine which localities have a coyote management website or a coyote management plan. We also included cities that have collaborated with the California Department of Fish and Wildlife in developing a “Wildlife Watch” program model. Wildlife Watch (based on the Neighborhood Watch national crime prevention program) uses conservation-oriented principles to empower local communities, agencies, and residents to remove wildlife attractants and to exclude or deter coyotes from neighborhoods. We examine how cities with coyote management websites and programs differ from cities without, based on U.S. census demographics. Using data from coyote conflict and sighting tools (Coyote Cacher, iNaturalist, and CDFW’s Wildlife Incident Reporting System) we compare coyote reports across cities with different management plans and websites. Finally, based on demographics from the US Census, we examine ways Wildlife Watch, or related programs, can be expanded and improved. An adaptive community-based program, like Wildlife Watch, offers a valuable toolkit to managers for navigating the diverse array of human perceptions, values, and attitudes regarding urban species and human-wildlife conflicts.