Fig 1.
Distribution of Crotalus willardi obscurus in North American (top picture), and magnified into a perspective of the three sky-islands in southwestern North America (bottom picture) that straddle southeastern Arizona (AZ), southwestern New Mexio (NM), and north-central México (MX).
PEL = Peloncillos Mountains (AZ); ANM = Animas Mountains (NM); SSL = Sierra San Luis Mountains (México). Numbers indicate specific locations of study sites, two of which are within Animas Mountains: (1) = West Fork Canyon (ANM-W); (2) = Indian Creek (ANM-I); (3) = Peloncillos Mountain; (4) = Sierra San Luis Mountain.
Fig 2.
Mean home range estimates for Crotalus willardi obscurus and six other rattlesnake species for which similar data were available.
Horizontal red bar = mean value. Cva = Crotalus viridis abyssus; Ca = Crotalus adamanteus; Scc = Sistrurus catenatus catenatus; Cc = Crotalus cerastes; Sce = Sistrurus catenatus edwardsii; Ch = Crotalus horridus. See Table 1 for literature citations and test statistics.
Fig 3.
Bioclimatic variables (WorldClim database) incorporated with193 GPS capture coordinates for Crotalus willardi obscurus in the sky Islands of southwestern North America provide climate envelopes and core habitat areas in ArcGIS 10.
Color density = strong habitat preference, with black/dark grey being most positive. Red circles = sampling locations. 2014 = current climate envelope; 2080 = a conservative climate envelope projected 66 years in the future.
Table 1.
Population demographic parameters for Crotalus willardi obscurus (= CWO) in the Animas Mountain sky island compiled by life history stage and population.
Table 2.
A Test of home range estimates for Crotalus willardi obscurus (= CWO) and six other rattlesnake species for which data are available, using analysis of covariance (ANCOVA) with gender and body size as covariates.
Table 3.
Declines in population growth (= r) for Crotalus willardi obscurus in the Animas Mountain sky island under four levels of inbreeding depression (i.e., None; Low; Moderate; High), as gauged using both deterministic and stochastic population models.
Table 4.
Sensitivity and elasticity estimates as derived from a population viability analysis (PVA) for Crotalus willardi obscurus (CWO) in the Animas Mountain sky island (New Mexico, U.S.A.).
Table 5.
Estimates for census size (= N), number of breeders (= Nb), and effective population size (= Ne) for the New Mexico Ridge-nosed Rattlesnake, Crotalus willardi obscurus (= CWO) in the Animas Mountain sky island.
Fig 4.
A conceptual diagram illustrating five key life history components that predispose short range endemics (= SREs) to extinction.
All five must be assesse to appropriately gauge long-term persistence of SREs in imperiled ecosystems.