Boat-based photo-identification research has been carried out on bottlenose dolphins in eastern North Pacific coastal waters off northern Baja California, Mexico and southern and central California, USA from 1981 to 2001. Within these waters, bottlenose dolphins routinely travel back and forth between coastal locations while generally staying within a narrow corridor extending only 1–2 km from the shore. Inter-area match rates for 616 dolphins photo-identified between 1981–2000 in four California coastal study areas (CCSAs) of Ensenada, San Diego, Orange County and Santa Barbara averaged 76%. To explore possible southern range limits for these dolphins, photo-identification surveys were carried out in the coastal waters off San Quintín, Baja California, Mexico between April-August 1990 (n = 8 surveys) and July 1999 to June 2000 (n = 12 surveys). The 207 individual dolphins identified off San Quintín were compared to the 616 dolphins identified in the CCSAs. The inter-area match rate between San Quintín and the CCSAs was 3.4% (n = 7 dolphins). This low rate contrasts sharply with the much higher average match rate of 76% observed between the CCSAs. These differences in match rates suggest that both a California coastal stock and coastal Northern Baja California stock may exist, with only a limited degree of mixing between them.

Red swamp crayfish (Procambarus clarkii) were first recorded in Topanga Creek in 2001. When the onset of drought in Southern California resulted in low flows and warming water temperatures from 2011–2014, the population rapidly increased. Within the Santa Monica Mountains, P. clarkii has been linked to diminishing numbers of California newt (Taricha torosa), a species of special concern (Kats et al. 2013). To address these concerns, a student-based citizen science program was conducted from November 2013 through April 2014 to remove crayfish from a 200 m reach of Topanga Creek. The following data was collected and compared between the removal reach and an upstream, adjacent 200 meter non-removal reach (control): water quality (temperature, salinity, pH, conductivity, dissolved oxygen, turbidity), nutrient levels (nitrate, nitrite, ammonia, orthophosphate), benthic macroinvertebrate community metrics, crayfish demographics and catch-per unit effort (removal reach only). The results indicate that red swamp crayfish presence or removals do not affect water quality or nutrient levels in Topanga Creek. However, benthic macroinvertebrate communities were significantly different between reaches; the presence of crayfish correlated with lower BMI abundance and species richness, higher proportion of tolerant taxa, and lower feeding group complexity.

Soil organic carbon and nitrogen storage represent important ecosystem services provided by salt marshes. To test the importance of vegetation on soil properties, we measured organic carbon, total nitrogen, and belowground biomass in two southern California salt marshes. In both marshes, cores were collected from areas which differed in dominant vegetation cover prior to the restoration of tidal influence. There were no differences in organic carbon or total nitrogen density between vegetation classes at either site; however, a relationship between belowground biomass and soil organic carbon suggests that vegetation may influence soil properties.

We provide an overview of the distribution of lowland and otherwise isolated populations of the western gray squirrel (Sciurus griseus) in the Los Angeles area of southern California, an area that has experienced a recent and ongoing invasion by the non-native eastern fox squirrel (Sciurus niger), an urban-adapted species introduced a century ago. Away from its strongholds in the western Santa Monica Mountains, San Gabriel Mountains, and Santa Ana Mountains, the western gray squirrel is resident locally in both the Santa Susana and the Verdugo Mountains, in Griffith Park, in low hills at the eastern periphery of the San Gabriel Valley and in Claremont, and along the Santa Ana River canyon near Yorba Linda. It also persists east of the Los Angeles area in residential areas of Redlands and Yucaipa, which as of 2014 are still outside the range of the eastern fox squirrel. Here we document several gray squirrel extirpation events within its lowland range, and discuss factors influencing its persistence and its extirpation.