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Great Salt Lake (GSL) is one of the largest and most saline lakes in the world. In order to accurately model limnological processes in GSL, hydrodynamic calculations require the precise estimation of water density (ρ) under a variety of environmental conditions. An equation of state was developed with water samples collected from GSL to estimate density as a function of salinity and water temperature. The ρ of water samples from the south arm of GSL was measured as a function of temperature ranging from 278 to 323 degrees Kelvin (oK) and conductivity salinities ranging from 23 to 182 g L−1 using an Anton Paar density meter. These results have been used to develop the following equation of state for GSL (σ = ± 0.32...
Increases in population density often are associated with a change in mating system structure in numerous taxa. Typically, male interactions are minimal in extremely low density populations. As density increases, males exhibit territoriality but if density becomes too high, the energetic cost of defending a territory will eventually outweigh the reproductive benefits associated with territoriality. Consequently, males in high density populations may abandon territoriality and adopt dominance polygyny, lekking behavior, or scramble competition. We investigated the relationship between population density and mating system structure in three populations of the chuckwalla, Sauromalus obesus (= ater), near Phoenix, Arizona....
Black-tailed prairie dogs (Cynomys ludovicianus) increasingly compete for available habitat with human development in the Colorado Front Range. Because the effects of increased urbanization on prairie dog colonies are unknown, we studied how landscape context affects prairie dog density in Boulder County, Colorado, USA. We used burrow density as a proxy for prairie dog density because these variables were correlated at our study sites (r=0.60). Using remotely sensed data and a GIS, we quantified percent urbanization, road density, and the percentage of other prairie dog colonies in the surrounding landscape at 200, 1000, and 2000 m from the perimeter of 22 prairie dog colonies, and compared burrow density with each...
Recent reintroduction of the black-footed ferret (Mustela nigripes) in west-central South Dakota has focused new attention on black-tailed prairie dogs (Cynomys ludovicianus), because prairie dog colonies provide essential habitat for ferrets. Currently, management agencies are assessing prairie dog populations by counting active burrows, a technique that is attracting criticism. We correlated active and total burrow counts with prairie dog mark-recapture population estimates from 12 colonies located in Badlands National Park and adjacent Buffalo Gap National Grassland. We also correlated visual counts of prairie dogs and counts of mounds from aerial photographs with mark-recapture estimates to assess an alternative...