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Synergistic 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.
Ocean 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 human-made 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, 42 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 < 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.
This study utilized native chaparral and sage scrub shrubs planted in lightly irrigated greenbelts around homes to evaluate the impact 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 that included adjacent thinned native shrublands and untreated control shrublands. However, in the summer and fall there were marked differences between treatments. 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 while possessing other desirable features of utilizing native vegetation.