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Recent decline of lowland populations of the western gray squirrel in the Los Angeles area of southern California
Full text linkWe 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
Mitigation Ponds Offer Drought Resiliency for Western Spadefoot (Spea hammondii) Populations
Full text linkSynergistic effects of habitat loss, drought, and climate change exacerbate amphibian declines. In southern California urbanization continues to convert natural habitat, while prolonged drought reduces surface water availability. Protection of biodiversity may be provided through mitigation; however, the long-term effectiveness of different strategies is often unreported. As a mitigation measure for building a new development within occupied Spea hammondii (western spadefoot) habitat in Orange County, California, artificial breeding pools were constructed at two off-site locations. Spea hammondii tadpoles were translocated from the pools at the development site to two off-site locations in 2005–2006. We conducted surveys a decade later (2016) to determine if S. hammondii were persisting and breeding successfully at either the original development site or the human-made pools at the two mitigation sites. We also verified hydroperiods of any existing pools at all three locations to see if any held water long enough for successful S. hammondii recruitment through metamorphosis. During our study, no pooling water was detected at two of three main sites surveyed, and no S. hammondii were observed at these locations. Twelve of the 14 pools created at only one of the two mitigation sites held water for over 30 d, and we detected successful breeding at seven of these pools. Recruitment in some mitigation ponds indicated that S. hammondii habitat can be created and maintained over 10+ yr, even during the fifth year of a catastrophic drought. Therefore, this may also serve as a conservation strategy to mitigate climate change and habitat loss. During our study, no pooling water was detected at two of three main sites surveyed, and no S. hammondii were observed at these locations. Twelve of the 14 pools created at a third site held water for over 30 days and we detected successful breeding at seven of these pools in 2016. Recruitment in some mitigation ponds indicated that S. hammondii habitat can be created and maintained over 10+ years, even during the fifth year of a catastrophic drought, therefore this may also serve as a management strategy for conservation with regard to climate change and habitat loss
Survival and Recruitment of Rehabilitated Caspian Terns in Southern California
Full text linkThousands of birds are taken in by animal care centers each year for rehabilitation. Birds returned to health by some centers are banded for later identification, but very few are ever reencountered following their return to the wild. We report here, information on the post-release survival of Caspian Terns (Hydroprogne caspia) in southern California as well as on their recruitment into a local breeding population and colony site fidelity
Are Fishes Attracted to Piers? Movements and Association of Marine Fishes to a Public Fishing Pier within a Commercial Harbor
Full text linkOcean fishing piers are ubiquitous along the world’s coastline, yet little research has examined how these structures can attract and retain fishes. Fishers routinely use these manmade structures as a reliable way to catch fish for subsistence or recreation. California halibut (Paralichthys californicus) and white croaker (Genyonemus lineatus) are commonly caught from fishing piers in southern California; however, some individuals have been found to contain high concentrations of hazardous contaminants. Thus, human health hazard warnings are posted throughout the Los Angeles area to limit fish consumption. To document attraction, residency, and association to fishing piers, forty-two California halibut and 198 white croaker were tagged with acoustic transmitters in regions of the Los Angeles and Long Beach Harbors, including a local fishing pier, and the movements of these fish were tracked throughout a 1.5 year period. Average (± SD) fish residency near piers was 90.5 ± 104.8 days for California halibut and 31.9 ± 25.7 days for white croaker. Only 18% of white croaker and 6% California halibut were detected migrating to the pier from other locations of the LA-LB Harbors, and most spent \u3c 10 min within 300 m of the public fish pier. Only 14% of California halibut and 0.35% of white croaker geo-positions were within casting range (approximately 30 m) of the pier, thus California halibut show the greatest potential affinity for pier habitat. Due to their movement patterns and habitat associations California halibut are much more likely to be attracted to fishing piers than white croaker
Protecting the WUI in California: Greenbelts vs thinning for wildfire threats to homes
Full text linkThis study utilized native chaparral and sage scrub shrubs to evaluate the impact of light summer irrigation on live fuel moisture content (LFMC) and predicted fire behavior. As to be expected LFMC varied markedly throughout the year being over 100% in winter in all species and treatments but differed markedly by treatment in the summer and fall. For most species lightly irrigated plants had the highest LFMC in the summer and fall, followed by thinned treatments and controls. These differences in moisture content coupled with structural differences in the vegetation contributed to expected differences in flame length and rate of spread. Lightly irrigated native shrubs planted around homes can reduce fire hazard and at the same time increase faunal diversity and other desirable features of utilizing native vegetation
Engaging Men on College Campuses: Gendered Assumptions in Sexual Assault Prevention Education Material
Full text linkA recent trend among sexual assault prevention programs is to target men rather than the traditional approach of focusing on women. The aim of this research is to analyze how sexual assault prevention education materials are used to engage men on U.S. college campuses and the gendered assumptions these programs make about men and about masculinity. Using discourse analysis methods, this research analyzes five sexual assault prevention programs curated for college men: A Call to Men, The Men’s Program, Men’s Workshop with Alan Berkowitz, Mentors in Violence Prevention, and Men Can Stop Rape. Programs curated with heterosexual, cisgender men as the exclusive intended audience work within a gender binary by assuming the best way to address this issue is to redefine masculinity rather than to deconstruct it. Critiquing gendered discourse and identifying patterns of assumptions allows us room to refine our messages to be more effective, which is imperative to addressing the issue of sexual assault on college campuses
The San Quintín Kangaroo Rat is Not Extinct
No full textThe San Quintín kangaroo rat (Dipodomys gravipes) is a medium-sized kangaroo rat restricted to a stretch of coastal habitat from San Telmo to El Rosario, Baja California, Mexico. Agriculture in the San Quintín area began in 1891 when British farmers converted parts of the landscape to agriculture. Now, much of the preferred habitat in the documented range of the species has been converted to agriculture. Dipodomys gravipes has a high affinity for flat terrain and is intolerant of cultivation. As a result of extensive and profound habitat alteration by agriculture, D. gravipes has been listed as endangered by the Mexican government. Since then, and given the lack of further captures, biologists and conservationists have feared the species could be extinct. However, Tremor and Vanderplank captured four specimens on 4 July 2017 on Mesa Agua Chiquita near San Quintín
