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New Mammal Atlas Documents San Diego Country's Unique Biodiversity
By Susana Rinderle
Imagine living in a county with the greatest diversity of mammals of any county in the United States. Now imagine this county also experiences immense stress through human expansion and climate change. But despite this, imagine there was no comprehensive guide to those mammals' identification, distribution, natural history, or conservation challenges.
That was San Diego County --- before 2017. That December, the San Diego County Mammal Atlas was published through a partnership among various agencies and local organizations. More than a decade in the making, the 432-page, full-color book is now the definitive guide to the mammals of San Diego County. It covers the biology of all 91 terrestrial species and 31 inshore marine visitors known to have occurred here since 1769.
Scott Tremor, a Mammologist at the San Diego Natural History Museum, was the principal author and editor of the Atlas. He specializes in surveying for and identifying southern California mammals, and his expertise, especially with rare rodents, spans Southern California and the Baja California Peninsula. This local experience and Scott's relationships with the experts in the region were essential to bringing this important book to life, which relies on historical and current survey data that he gathered over many years.
"Before the Atlas's creation, little information was publicly available on our region's mammals," he says. "Even more concerning is San Diego County's designation as a biodiversity hotspot—an area with immense biodiversity and human impact. This high-risk situation prompted us to compile everything we could fit into a single, user-friendly compendium." The Atlas, therefore, serves as an invaluable reference for mammals within Anza-Borrego Desert State Park and its surrounding areas. The book addresses all mammals, especially the less charismatic, like rodents and bats, that often don't receive as much attention as the bigger, showier mammals like coyotes, bobcats, and bighorn sheep.
The Atlas is a compilation of written accounts and point data starting with 18th-century Spanish explorers who first documented San Diego's wildlife. Those point data are utilized in the mapping section for each species account. Also included in each account is comprehensive detailed information, including physical descriptions, comparisons, distribution, habitat, diet, reproduction, space-use patterns, activity patterns, predators, behavior, detection in the field, conservation status and research needs. In addition, body part measurements such as range and average length of body, tail, hind foot, ear, and skull features are often included to help readers distinguish specimens to the species or subspecies level.
"Before the Atlas's creation, little information was publicly available on our region's mammals," - Scott Tremor
The San Diego County Mammal Atlas is cited on Research Gate and described in detail on the San Diego Natural History Museum website. It's available for purchase at the Museum and through Sunbelt Publications. Scott also presented on the Atlas and at the "Anza-Borrego: In Focus" lecture series last March.
"This book is written for a general audience as well as the professional biologist/wildlife manager," he says. "There are hundreds of full-color photographs, rich descriptions and fascinating tidbits on each species' natural history. For anyone curious about our region's local mammals, this book offers more than just a basic introduction without getting too far into the weeds. It is comprehensive, well-organized, yet aesthetic enough for a coffee table."
Scott is currently working on other projects studying rare species. He and other researchers are investigating why the San Bernardino flying squirrel now appears extirpated from the San Jacinto Mountains but remains in the San Bernardino Mountains. Scott also rediscovered the San Quintin kangaroo rat that was thought extinct near San Quintin in Baja, California. He continues to study animals in the region likely affected by climate change. He's also excited to study the range and taxonomy of the chaparral chipmunk, which occurs only in Southern California and on isolated Baja California peninsula mountain ranges.
If you would like to reach Scott, please get in touch with him at stremor@sdnhm.org
