Squamate fossil identification has been challenging due to the incomplete understanding and sometimes complete lack of osteological research of extant species. Here we compared the maxilla of two similar species of phrynosomatids: Uta stansburiana (Common Side-blotched Lizard) and Urosaurus ornatus (Ornate Tree Lizard). Through landmark-based geometric morphometric analyses, we determined which characters significantly separated the two species. A principle component analysis (PCA) and a stepwise discriminant function analysis (DFA) were conducted, in which we compared 15 landmarks between U. stansburiana and U. ornatus. Both the PCA and stepwise DFA showed separation between the two species. The stepwise DFA selected five of the 15 characters as statistically significant, three of which are considered apomorphies and show promise for fossil identification. The first character is in the ventral region of the posterior maxilla process; U. ornatus has a defined notch, whereas U. stansburiana does not. The second and third characters are in the anterior portion of the maxilla, which is curved dorsally in U. stansburiana, whereas U. ornatus shows no curving. The results of this study are used to identify fossil Uta vs Urosaurus, but more analyses need to be conducted on other phrynosomatid species for comprehensive identification.

Long-term lifecycle monitoring of federally endangered southern steelhead trout (Oncorhynchus mykiss) in Topanga Creek provides a unique opportunity to examine the health and abundance of a steelhead population before (2008--2011) and during (2012--2016) a prolonged drought. We found that the five-year drought resulted in a substantial and significant decline in available wetted habitat suitable for rearing and upstream migratory access for anadromous adults. The response of the steelhead population has been a significant reduction in anadromous spawning, distribution of rearing, and abundance of all life stages of anadromous and resident steelhead. After five years of drought a population that exceeded 325 individuals in 2008, now numbers fewer than 50 fish, and appears to be at extremely high risk of extirpation. Acknowledging the possibility of increased drought regionally and globally, the need to bolster southern steelhead resiliency to additional disturbance is paramount.

This pilot study developed a longitudinal temperature profile of the Los Angeles River by deploying temperature loggers throughout the watershed between June and October 2016. The watershed was divided into zones based on river system component, urbanization, and channelization. Channelized sites recorded the highest temperatures, tributaries recorded the lowest, and the estuary showed the most fluctuation. Overall, temperatures were too warm to support re-introduction of native fish but currently support non-native fish species. Temperature mitigation is needed for native species to re-establish. Albeit limited in scope, this study establishes a baseline of summer/fall temperatures in the Los Angeles River.

The eastern fox squirrel, Sciurus niger, has been introduced to many areas outside of its native range. Once introduced to a new region the species has generally expanded its geographic range and is considered to be an invasive species, causing both ecological and economic harm. While some information is available on where introductions have occurred, detailed information is not available on the current geographic distribution of the species within California. Since invasive species tend to be under-represented in specimen collections at museums, new methods for obtaining location data were needed. We used a time period of 1995 through 2015 for observations so that location data would be most up-to-date. A majority (51%) of location data used in this study came from wildlife rehabilitation centers, approximately 31% came from citizen-science type sources such as the California Road-Kill Observation System, a previously published journal article, and research-grade submissions to iNaturalist, 10% came from the California Department of Public Health West Nile Virus Surveillance Program, and 8% came from the authors and trained student observers. Maps are presented to show the current geographic distribution of the species indicating a broader range than what was previously known.

The goals of this study were to map the distribution of the invasive eastern gray squirrel, Sciurus carolinensis, in California as of 2015 and to assess range expansion since the first documented sightings within the state. Range maps exist, but the last update by the California Department of Fish and Wildlife was in 2007. An assessment of the rate of range expansion over time has not been conducted, but comparisons between the locations of initial sightings and the current distribution are included. Location data were obtained from museum specimens, wildlife rehabilitation centers, a roadkill database, and research-grade citizen observations. Range maps were produced with ArcGIS software. Populations of eastern gray squirrels are currently concentrated around Sacramento and Davis, the western side of San Francisco Bay, within as well as north and east of Santa Cruz, within Monterey, north of the Golden Gate Bridge through Marin County as well as around Santa Rosa, and around the Bellota/Stockton area. Isolated populations on the eastern side of San Francisco Bay occur around Berkeley, Hayward, and Pleasanton. Observations extend into the foothills of the Sierra Nevada Mountain Range from north of the American River to south of the San Antonio River. We suggest that the eastern gray squirrel might become more damaging to the two native diurnal species of tree squirrels in California, Sciurus griseus and Tamiasciurus douglasii, than the introduced eastern fox squirrel (Sciurus niger).