Coues white-tallied deer (Odocoileus virginianus couesi) and desert cottontail (Sylvilagus auduboni), also known as Audubon cottontail, are inhabits of oak savannas in the Southwestern Borderlands region. Food, cover, and scattered water for these two species are found in this comparatively open ecosystem. The results of a study on the presence (occurrence) of Coues white-tailed deer and desert cottontail in unburned the oak savannas of the Southwestern Borderlands Region are presented in this paper. Effects of cool-season and warm-season prescribed burning and a wildfire on the presence of these two species are also reported.

Parents sometimes discriminate offspring from non-offspring while responding to vocalizations, ensuring that parental care is directed towards their progeny exclusively. This discrimination may result from differences in acoustic characteristics across individuals. However, recognition capabilities specific to individuals may not occur when parents differentiate offspring via location because litters are segregated spatially. Offspring discrimination is important during “distress calls” emitted by young-of-the-year for imminent danger because mothers that respond to non-offspring reduce the time available for protecting their litter, and failure to respond may result in offspring mortality. Columbian ground squirrel (Spermophilus columbianus) pups sometimes emit a scream-like distress call near their mothers when attacked by marauding conspecifics. With field observations of infanticide and playback experiments that manipulated the identity and location of the caller, I examined whether a location-based rule or vocal recognition per se mediate female responses to distress calls. Mothers became vigilant and approached the speaker in response to playbacks of distress calls broadcast on their territory, regardless of whether the recording was an offspring or non-offspring. However, mothers approached distress call recordings originating on their territory more often than those occurring on adjacent territories. Thus, female Columbian ground squirrels respond to distress calls based on a location-based rule (viz., on or off their territory) rather than true vocal recognition. This strategy seems appropriate, since lactating females are territorial and pups rarely mix between litters during the 1–5 day period just after emergence from their natal burrow when they are susceptible to infanticide.

Soil temperatures are typically measured at shallow depths near the soil surface where large diurnal variations occur. For depths deeper than about 50 cm analytical and numerical models are often used to simulate the annual variations in daily temperature, which require information about the soil thermal diffusivity (D). An analytic solution to the onedimensional Fourier heat conduction equation was used by Matthias and Warrick (1987) to simulate daily soil temperatures at 20 and 100 cm depths at Safford, Arizona, and at 20 cm depth at Yuma, Arizona, using observed daily soil temperatures at 10 cm depth at each location and an estimate of the average soil thermal diffusivity as inputs. The solution was the sum of a deterministic (mean annual wave) component and a stochastic (daily fluctuations about the mean wave) component. The purpose of the research described in this paper is to use the model described by Matthias and Warrick (1987) to calculate the average thermal diffusivity for a semi-arid rangeland soil at the Page Ranch near Oracle, Arizona. The data used in this analysis were the daily soil temperatures at 50, 100, 300, and 500 cm depths observed during a one-year period from July 1, 1983 to June 30,1984 at the site. To obtain the average D, the daily temperatures at 50 cm depth and an initial estimate of D were input to the model to simulate temperatures at the 100, 300, and 500 cm depths. Observed and simulated temperatures at each depth were then compared. If the root-mean-square-deviations (RMSD) between observed and simulated values were large then an updated value of D was input to the model and temperature values recalculated. This trial-and-error approach continued until RMSD values were minimized. With D∼500 cm² d^-1 good agreement between observed and simulated temperatures was achieved with RMSD values ranging from 0.38 to 1.35 °C for the three depths.

The remains of a mastodont and mammoth were recovered from Pleistocene deposits in southeastern Arizona. These new proboscidean remains have characteristics distinguishing them from their more typical late Pleistocene forms. The mastodont (Mammut americanum), has traits similar to those of other female mastodonts, but includes mandibular tusks. This may indicate an early Pleistocene Age or supports evidence that female mastodonts had mandibular tusks. The partial mammoth jaw and molar display characteristics similar to Mammuthus columbi, but appears to be a variant or earlier form approaching those displayed in Mammuthus meridionalis. The presence of different proboscideans with different diets, although within the same geologic unit, cannot be confirmed as being sympatric. If so, it would indicate a partitioning of resources. Mammoths are grazers, and more common in Arizona than the browsing mastodonts.

This study examines the mobilization of cyanide (CN^-) and trace elements from the Eagle Milling Site situated in the Eagle Wash of Nelson, Nevada. Contaminants (CN^- and mercury [Hg]) utilized for the extraction of precious metals from ores are subject to environmental release, but concentrations of other trace elements in sediments and their enrichment ratios indicate that mobilization of trace elements lead (Pb), arsenic (As), selenium (Se), and barium (Ba) has also occurred. Storage of milling wastes in Eagle Wash and subsequent storm water mobilization and transport has resulted in increases in CN^-, Hg, Pb, As, Se, and Ba in wash sediments some 6,000 m from the source area. On the basis of enrichment ratios, the Eagle Wash was found to contain CN^-, Hg, Pb, As, and Ba above background levels in wash sediments. Selenium increased slightly in concentration; chromium (Cr) decreased consistently; and silver (Ag) and cadmium (Cd) were not detected. Cyanide, Hg, Pb, Ba, Se, and As enrichment ratios were > 1.5, indicating anthropogenic enrichment in sediments, whereas Cr enrichment ratios were <1.5, indicating no anthropogenic enrichment.

Non-native tamarisk (Tamarix spp.) widely colonized riparian habitats and reservoir shorelines across elevation throughout the western United States during the 20^th century. To improve understanding of tamarisk reproductive plasticity, we compiled elevation, date, and phenology data from specimens in Southwestern herbaria, and we conducted field studies in Glen and Grand Canyons from 1984–2009. We modeled tamarisk reproductive seed-release phenology across elevation in relation to hydrography and flow management in the Colorado River Basin. We compared the potential for tamarisk recruitment in the pre- and post-dam Colorado River mainstream with that in Lake Mead and Lake Powell reservoirs and in tributaries with low- or high-elevation headwaters. Flooding timed with seed release was likely to result in tamarisk recruitment. Conversely, planned floods from Glen Canyon Dam that specifically avoided the May-June peak tamarisk seed-release period resulted in little tamarisk recruitment downstream in Grand Canyon. Failing recruitment in the post-dam Colorado River mainstream in Grand Canyon has occurred because: (1) the spring-summer hydrograph is generally unsuitable for tamarisk seedling establishment, and (2) post-dam flooding has coarsened grain size, resulting in less stable soils with lower nutrient concentrations. Hydrograph management can result in reduced tamarisk recruitment, while poorly timed floods, simulated natural flow regimes, and unregulated tributary flows permit tamarisk establishment. We discuss tamarisk life history in relation to ongoing environmental changes in biological controls and habitat management.

The Cuatro Ciénegas Valley is a protected area that contains numerous hot and cold pools with varying salinity and hosts a large variety of endemic species, from stromatolites to algae and birds. Human activities threaten to consume the water resources and the abundant gypsum outcrops that support endemic vegetation species. The research results showed that significant changes, as reduction of up to 80% in the size of the pools, occurred in the study area as well as a decrease in the gypsum-covered areas. The changes are mostly related to human activities, as farming and mining that cause overexploitation of the aquifers and unregulated gypsum exploitation. The conservation plans of the ecosystem in this special area must take into account the change rate in the land cover and pools size in order to regulate land use and aquifer exploitation.

Detailed taxonomic information on Arizona's springsnail species (Pyrgulopsis) exists, but few studies have looked at their life history and the environmental conditions required for reproduction. These biological parameters are difficult to observe and quantify in the field due to the small size and aquatic nature of the genus. Biologists at the Phoenix Zoo's Arthur L. and Elaine V. Johnson Conservation Center used Page springsnails (Pyrgulopsis morrisoni) to develop and refine husbandry and management protocols that allowed us to monitor the snails' numbers, changes in water temperature, dissolved oxygen levels, and water chemistry. Additionally, we were able to track their reproductive cycle, and record changes in their appearance and size during development. These biological parameters and developmental changes would be very difficult, if not impossible to observe in the field. Information gained from this work has direct applications towards both ex situ and in situ conservation of rare hydrobiid snails. Most notably this approach allowed us to maintain Page springsnails ex situ, and to observe the first reproduction of this species outside of its natural habitat.