Robert C. Thomson - California Amphibian and Reptile Species of Special Concern

California boasts one of the most biologically diverse faunas in the United States, as well as one of the most threatened. One of the key elements of the states efforts to protect its vertebrate fauna is through its Species of Special Concern program. The current volume, California Amphibian and Reptile Species of Special Concern , is an essential foundation upon which both biologists and state and federal agencies can manage the biological resources of the state. California has exceedingly sensitive species and ecosystems, many of which are at risk of extirpation or extinction as the states environment changes at rates greater than at any time in history.

This book builds upon the shoulders of its predecessor from two decades ago (Jennings and Hayes 1994a), but it is not just a simple update. Jennings and Hayes surveyed an enormous number of experts to create a comprehensive publication on Californias special concern amphibians and reptiles, and their volume was a key management tool for a generation of biologists. However, this new book goes several steps further, making it a necessary reference for wildlife and land managers, biologists, and nature lovers interested in amphibians and reptiles.

First, the maps generated for this book are stunning. They are literally beautiful enough to be framed, and detailed enough to guide resource managers. Second, there are color images of every taxon, generally taken in the field and highlighting the key features of each species. Third, the authors rely on the published literature to the maximum extent possible, pulling in the gray literature only when it is needed (which is often because many of these species are poorly known). But perhaps most importantly, the authors used multifactorial risk metrics that bring several measures of potential and actual threat into a single numeric score that captures the sensitivity of the species. The result is a tool that provides an important first pass at the difficult task of identifying those taxa that should be candidate Special Concern species.

Of course, there will always be important biological considerations that may argue against a strict interpretation of the metric scores, as the authors fully realize. For example, there are species on the Special Concern list that are so narrowly precinctive that the narrowness of their geographic range alone signals reason to be extra cautious about the species. The sandstone night lizard is one such taxon; its geographic range is much smaller than listed species such as black toad ( Bufo exsul) , and we know much less about the night lizard than we do about black toads. Regardless of the risk model score, this is a scary situation, and the narrowness of geographic range alone signals reason to be extremely cautious. Herpetologists are well aware of extinctions of entire species that were so narrowly precinctive that very subtle (sometimes unknown) environmental changes have caused those extinctions (e.g., the golden toad of Costa Rica, which had a geographic range the same size as that of the sandstone night lizard).

There are other species covered in this volume that will be challenging to manage for their protection in California. For example, the Gila monster ( Heloderma suspectum ) can be found in the extreme eastern part of the Mojave Desert in California (east of 116 longitude), where it has been recorded fewer than 30 times in the last 150 years. Within the distribution of Gila monsters in California, the pattern of rainfall includes winter rains and summer (monsoonal) rains; this biphasic pattern is typical in Utah, Nevada, and Arizona where Gila monsters are relatively more common. Throughout their geographic range, Gila monsters depend upon climate conditions conducive for reproduction by small mammals because neonatal small mammals are the principal prey for this species. However, climate is demonstrably changing in California to be warmer (especially in summers) and with increased frequencies of drought. These changes may not be mitigable at a local level, and this creates conservation challenges. Nevertheless, knowledge of both changes of climate and the biology of Gila monsters is meager, and this signals both that the Gila monster is clearly a reasonable candidate for SSC status and a need for additional research.