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This dataset provides spatial predictions of habitat suitability for Gopherus agassizii (Agassiz’s desert tortoise), Gopherus morafkai (Morafka’s desert tortoise) and a pooled-species model under current conditions (1950 – 2000 yr). The raster layers contained here accompany the manuscript Inman et al. 2019 and were used to evaluate subtle ecological niche differences between G. agassizii and G. morafkai, and identify local species-environment relationships. Spatial predictions of habitat suitability were created using MaxEnt version 3.4.0 (Phillips et al., 2006), a widely-used software for SDM in presence-background frameworks. Detailed methods are provided in Inman et al. 2019. Inman et al. 2019. Local niche...
The relationships between Mycoplasma agassizii, a causative agent of upper respiratory disease (URTD), and desert tortoise (Gopherus agassizii), generally illustrate the complexities of disease dynamics in wild vertebrate populations. In this review, we summarize current understanding of URTD in Mojave desert tortoise populations, we illustrate how inadequate knowledge of tortoise immune systems may obfuscate assessment of disease, and we suggest approaches to future management of URTD in desert tortoise populations. We challenge the view that M. agassizii causes consistent levels of morbidity and/or mortality across the Mojave desert. Instead, URTD may be described more accurately as a context-dependent disease....
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This dataset provides spatial predictions of clustering and the genotype association index for the Mojave genotype in local species-environment relationships of Desert Tortoises (Gopherus agassizi and Gopherus morafkaii) for individuals in the subregion encompassing the genetic sampling locations used by Edwards et al. (2015). This region offered an opportunity to explore habitat selection across the ecotone between the Mojave and Sonoran deserts and the secondary contact zone between G. agassizii and G. morafkai, and is referred to as the focal study area. The raster layers contained here accompany the manuscript Inman et al. 2019 and were used to identify multivariate clusters and map them back to geographic space....
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This dataset depicts the distribution of Desert Tortoise habitat in Arizona. This dataset was obtained from Arizona GAP with no metadata.
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This dataset provides spatial predictions of the pooled-SDM residuals from a multiscale geographically weighted regression model (MGWR) and the resulting local R2 values for individuals in the subregion encompassing the genetic sampling locations used by Edwards et al. (2015). This region offered an opportunity to explore habitat selection across the ecotone between the Mojave and Sonoran deserts and the secondary contact zone between G. agassizii and G. morafkai, and is referred to as the focal study area. The raster layers contained here accompany the manuscript Inman et al. 2019 and were used to identify multivariate clusters and map them back to geographic space. Inman et al. 2019. Local niche differences predict...
In the Sonoran Desert of North America, populations of the desert tortoise (Gopherus agassizii) occur in rocky foothills throughout southwestern Arizona and northwestern Mexico. Although tortoise populations appear to be isolated from each other by low desert valleys, individuals occasionally move long distances between populations. Increasingly, these movements are hindered by habitat fragmentation due to anthropogenic landscape changes. We used molecular techniques and radiotelemetry to examine movement patterns of desert tortoises in southern Arizona. We collected blood samples from 170 individuals in nine mountain ranges and analyzed variability in seven microsatellite loci to determine genetic differentiation...
1. 1. Deep body and shell surface temperatures were monitored via radio-telemetry from unrestrained desert tortoises in their natural habitat. 2. 2. The surface of the carapace acts as a buffer against solar radiation, resulting in deep body temperatures up to 10�C below shell surface at the time of the midday retreat to burrows. 3. 3. The burrow of the desert tortoise provides the only ambient temperatures at ground level which are below the lethal range for this species during midday hours. 4. 4. Evening retreat to burrows permits an extension of higher body temperatures into the mid-evening hours. 5. 5. The use of evening burrow retreats lessens in mid-summer. This behavioral change results in lower body temperatures...
Egg production by desert tortoises was estimated at two sites in San Bernardino, California: Ivanpah Valley in 1980 and 1981 and Goffs in 1983, 1984 and 1985. Mean clutch frequencies were estimated for 1980 (1.60) and 1981 (1.10) from mass changes observed among sexually mature females weighed every 1-2 wk. Mean clutch frequencies in 1983 (1.89), 1984 (1.57) and 1985 (1.75) were estimated from periodic X-rays of females. Clutch sizes were also determined from radiographs. Tortoises at Goffs typically laid 1-2 clutches during May and June, but one female failed to lay eggs in 1984 and single tortoises laid three clutches in 1983 and 1985. If tortoises laid two clutches, the second was faintly visible in X-rays within...
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This USFWS data set has been modified by NatureServe to include critical habitat only within the Central Basin and Range, and Mojave Basin and Range ecoregions, and further modified to include only the desert tortoise (Gopherus agassizii). These data identify, in general, the areas where final critical habitat exist for species listed as endangered or threatened.
The USGS GAP Analysis Program has developed range maps and distribution models for 1401 species, 604 of which are found within the SRLCC. This record's parent folder contains several examples of GAP species web services. The GAP website has a complete list of available web services for species as well as a map viewer for species data. Species: Desert Tortoise (Gopherus agassizii) There are two web services for this species: the range map, showing the geographic limits within which the species can be found, and a distribution model, which predicts the environment within the range that is suitable for occupation by the species. Link to metadata for GAP range maps and distribution models. To access services, select...
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The purpose of this layer is to depict information relevant to the conservation of the desert tortoise (Gopherus agassizii) under the Desert Renewable Energy Conservation Plan (DRECP). Its extent includes all desert tortoise conservation areas (TCAs) identified in the US Fish and Wildlife Service's (USFWS) recovery plan for the desert tortoise and a series of least cost pathway linkages that connect these TCAs. The least cost pathway linkages were mapped by the USFWS Desert Tortoise Recovery Office (DTRO) and the University of Redlands. For the purpose of DRECP planning, this layer provides a more detailed assessment of this broad conservation network and identifies how different geographic areas within this network...


map background search result map search result map GAP Web Service: Desert Tortoise Desert Tortoise TCA Habitat Linkages, DRECP Habitat Genotype Association Local Niche Model Spatial Predictions of Mojave Desert Tortoise, Sonoran Desert Tortoise and Pooled Species Habitat Suitability for present-day (1950 – 2000 yr) BLM REA SOD 2010 Desert Tortoise Distribution in Arizona (GAP) BLM REA CBR 2010 PLII CBR crithab poly tortoise BLM REA CBR 2010 PLII CBR crithab poly tortoise BLM REA SOD 2010 Desert Tortoise Distribution in Arizona (GAP) Desert Tortoise TCA Habitat Linkages, DRECP Habitat Genotype Association Local Niche Model Spatial Predictions of Mojave Desert Tortoise, Sonoran Desert Tortoise and Pooled Species Habitat Suitability for present-day (1950 – 2000 yr) GAP Web Service: Desert Tortoise