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Phoenix, AZ, United States

Daren Riedle J.,000 West Carefree Highway | Daren Riedle J.,West Texas A&M University | Averill-Murray R.C.,000 West Carefree Highway | Averill-Murray R.C.,U.S. Fish and Wildlife Service | Grandmaison D.D.,000 West Carefree Highway
Journal of Herpetology | Year: 2010

We determined annual survivorship and causes of mortality at two Desert Tortoise, Gopherus agassizii, study sites in the Sonoran Desert, Arizona, based on radio-telemetry data. Annual survivorship was high (8997), did not differ between sexes, and was comparable to previous studies using markrecapture methods. Survivorship between sexes differed seasonally at one site, based on differences in seasonal activity patterns and differential exposure to predation by mountain lions, Puma concolor. In the absence of mammalian predation, seasonal survivorship did not differ between sexes. The next leading cause of mortality was failure to right oneself after a fall or after being flipped during reproductive or combat events. © 2010 Society for the Study of Amphibians and Reptiles.

Hershler R.,Smithsonian Institution | Liu H.-P.,University of Denver | Carlton J.T.,Williams College | Cohen A.N.,Center for Research on Aquatic Bioinvasions | And 3 more authors.
Aquatic Invasions | Year: 2015

We report the discovery of a second western Atlantic brackish-coastal cochliopid gastropod in San Francisco Bay [Spurwinkia salsa (Pilsbry, 1905)], and detail the first records for a widely distributed member of the family, Tryonia porrecta (Mighels, 1845), from artificial lakes (in the Phoenix metropolitan area). These identifications were based on morphological criteria and supported by mitochondrial DNA sequence data that also indicates little or no divergence of the newly reported populations, which is consistent with evolutionarily recent spread or separation. Spurwinkia salsa was most likely introduced to San Francisco Bay either in recent decades in bait worm packing or ships’ ballast or in the 19th or early 20th century in solid ballast or with oyster imports. The discovery of T. porrecta in artificial lakes in the Phoenix area in 1984 and 2014 may be due to either recent arrival in the area or to dispersal into a newly available habitat from a population long present in the area. In either case, the occurrence of T. porrecta in the Phoenix area is likely due to transport on birds along an eastern branch of the Pacific Flyway. The discovery of T. porrecta in artificial lakes suggests that this species (which is typically distributed in thermal springs) is more broadly tolerant than previously thought. Additional spread of this unusual snail within the highly modified aquatic ecosystem of the Phoenix metropolitan area (which includes more than 900 artificial lakes) would appear likely. © 2015 The Author(s).

Grandmaison D.D.,000 West Carefree Highway | Ingraldi M.F.,000 West Carefree Highway | Peck F.R.,U.S. Army
Journal of Herpetology | Year: 2010

We examined Desert Tortoise microhabitat selection on the Florence Military Reservation (FMR) in south-central Arizona where National Guard training and other activities, such as motorized recreation and grazing, are permitted. Previous research on the FMR indicated that Desert Tortoise home ranges overlapped with firing boxes, areas where most of the National Guard's training activity was concentrated. Our objective was to examine Desert Tortoise microhabitat selection within, and adjacent to, these firing boxes in an effort to guide future management for restoring degraded tortoise habitat on the installation. Desert Tortoises selected habitat that was characterized by a higher percentage of canopy cover, absence of cattle activity, and closer proximity to roads and washes than was available within their home range. Canopy cover had the highest calculated parameter importance and was included in each of the supported microhabitat selection models. Areas with sufficient canopy cover most likely provided shade for escaping the desert heat during periods of high tortoise activity. Our results suggest that management prescriptions that maintain, or increase, the amount of vegetative cover and that protect desert washes will have positive impacts on Desert Tortoise populations. Copyright 2010 Society for the Study of Amphibians and Reptiles.

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