Traditionally only four deserts have been recognized in North America: the Great Basin, Mojave, Sonoran, and Chihuahuan. These deserts were recognized based on general aridity, soil types, and arid-adapted plants and animals. The San Joaquin Valley had been classified by many biologists as either a perennial or annual grassland, although some recognized the desert nature of the area in works peripheral to the specific nature of the area. After conducting field studies for 20-25 years on various plants and animals in many parts of the San Joaquin Valley, my colleagues and I set out to formally recognize the San Joaquin Desert that makes up about two thirds of the valley and adjacent areas. Based on coincident ranges of low precipitation, arid soils, and plants and animals that are clearly desert adapted, we delineated the boundaries of this fifth North American desert. Because of the high number of protected species, many of which are endemic to this desert, it is important to recognize the true nature of this part of California so that management actions to restore habitat do so with the aim of reestablishing the correct plant communities.

As an imperiled ecosystem inhabited by multiple threatened and endangered species, the San Joaquin Desert has long been a focus of research, but recovery efforts did not gain much momentum until the 1990s. Since the USFWS published the “Recovery Plan for Upland Species of the San Joaquin Valley, California” (USFWS 1998) conservation and recovery efforts have greatly increased, with many organizations using the recovery goals of the plan to shape research and conservation actions. Highly visible efforts, such as the Endangered Species Recovery Program, CDFW, and easements set aside for mitigation, along with many other efforts are contributing to conservation and recovery. Consultants can fill many roles in these efforts, both through client-driven project actions and as a complement to direct conservation activities. Contributions can also be made in the form of internships and entry-level employment to students, new graduates, and early career professionals who could be the conservation researchers and wildlife managers of the future.

California ground squirrels (Otospermophilus beecheyi; CAGS) and endangered San Joaquin kit foxes (Vulpes macrotis mutica; SJKF) frequently occur sympatrically. CAGS control strategies include lethal measures administered within CAGS burrows, which could harm or kill a SJKF if mistakenly applied to an occupied SJKF den. To identify attributes to distinguish between SJKF dens and CAGS burrows, we assessed dimensions, penetration depths, ejecta patterns, and the presence of various types of sign at 65 known SJKF dens and 80 CAGS burrows. Mean entrance height, width, and circumference all were significantly larger for SJKF dens. However, the ranges of values for all dimensions for the CAGS burrows encompassed the ranges for the SJKF dens. Penetration depth analyses revealed some general trends, but few absolute criteria to distinguish between the two. Dirt berms, scat, prey remains, and trash were observed at both SJKF dens and CAGS burrows. None of the attributes we assessed provided unequivocal criteria for distinguishing between SJKF dens and CAGS burrows. Also, SJKF occasionally usurp CAGS burrows and CAGS occasionally move into SJKF dens. Therefore, administering lethal control measures within burrows should be avoided as it presents a risk to SJKF and many other species that may use CAGS burrows.

For most endangered species in the San Joaquin Valley, the only hope for recovery, until recently, has been acquisition, restoration, and management of the few intact habitat remnants left after 100+ years of land conversion. The Sustainable Groundwater Management Act, passed in 2014 and designed to help California achieve groundwater sustainability, has given these species another pathway to recovery, through restoration of the more than 500k acres of farmland expected to be retired to achieve groundwater sustainability. Over the past five years, The Nature Conservancy (TNC) and partners have identified properties across the Valley that will allow us to achieve species recovery – with restoration – of more than 20 species over the next 25 years and for sustainable farming to continue in the Valley, while supporting clean water and air initiatives. And now, in partnership with diverse farming, conservation, and community partners, TNC has begun to experimentally design habitat restoration projects to be cost effective learning laboratories that will realistically allow us to scale the initial 500-acre pilot projects to more than 50,000 acres over 25 years. Working together with seed companies and restoration and farming professionals, we are testing novel approaches to habitat design and creation while laying the groundwork for sustainable native seed production, all with an eye towards developing new economies of scale that will support more and more efficient future projects.

The San Joaquin Desert is among the most impacted ecosystems on earth. Thanks to a generation of conservation effort, endangered, endemic species such as the giant kangaroo rat and San Joaquin kit fox have secure populations, and a path toward down- or even de-listing is in sight. Unfortunately, one of the most astonishing processes has not returned: the enormous and widespread herds of migratory or nomadic pronghorn reported fewer than two centuries ago. Yet, given changes at the landscape level, it is not well understood if current conditions can support a productive and stable pronghorn population. Restoring pronghorn across the San Joaquin Desert will require landscape-scale planning, engaging with state, federal and international public agencies, as well as private landowners. Pronghorn need reliable access to freshwater, modified fences and roads, and rangelands dominated by a mix of forbs and shrubs rather than non-native annual grass. Success may require large corridors for migration. Pronghorn can serve as an indicator of ecosystem health, an umbrella for conservation, and a flagship for diverse stakeholder support. In this talk, we suggest that reestablishing a self-sustaining, stable pronghorn population to the region may move us closer to a more fully functioning and resilient San Joaquin Desert.

In 2020, the unique, northern-clade population of Blunt-nosed Leopard Lizards (Gambelia sila) on Panoche Plateau declined to less than 10 individuals. We received emergency permission to collect 5 animals in 2020 and 2 animals in 2021 to found an assurance colony at Fresno Chaffee Zoo. We successfully bred these animals, producing >100 offspring in three years, and released 17 ~10-month old animals back to Panoche Plateau in 2023. Each animal was radio-collared and regularly monitored throughout the 2023 active season. Although lizards displayed high survival (41% confirmed survival, and 47% slipped collars with no sign of predation), they moved and grew little compared to wild animals, and they did not reproduce. We discuss potential causes for minimal movement and growth and changes we are implementing to our protocols to improve success moving forward. We will continue releasing and monitoring G. sila annually until >50 natural-born female G. sila successfully reproduce for at least 2 years, at which point we think the population will be able to self-sustain and grow to carrying capacity.

Mitigation lands protected under conservation easement or fee title conveyance often require annual species monitoring by the stewardship entity responsible for its management. By developing these monitoring activities in association with one another and within an experimental framework, managers have an opportunity to leverage monitoring data to explore long-term research objectives that can help improve conservation outcomes and inform management strategies within and beyond its borders. Since 2019, the Center for Natural Lands Management has set about applying this approach to its Panoche Valley Preserve, a 26,420-acre conservation property within the Ciervo-Panoche Natural Area, which has been identified as a core area of habitat for the conservation and recovery of numerous San Joaquin desert species. Here, I will discuss practical insights gleaned from the development of the Preserve’s landscape scale research and monitoring regime and share preliminary findings following the conclusion of its five-year, baseline data collection period.

Located in the southern Central Valley, the San Joaquin Desert is the smallest, least recognized and most imperiled true desert in North America, with less than 40% of its original area remaining. The desert was not formally described until 1995 and didn’t gain recognition by the scientific community until 2011. The San Joaquin Desert is floristically distinct with 37 near-endemic and 40 strict endemic plant species. Nearly half of the species are imperiled and listed as endangered, threatened, rare or watch status. This presentation will delve into why it took so long for the San Joaquin to be recognized as a desert, how it is both climatically and floristically similar to the Mojave Desert and what we can do to conserve what little of it remains.