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The M & M mastodont is one of only a few described specimens of Mammut americanum in Arizona. This contrasts to the large number of sites reporting mammoth remains. The preserved remains of the mastodont indicate it was a large male, but not an aged adult. Radiocarbon dates associated with the mastodont reveal a late Pleistocene (Rancholabrean) age for the mastodont. Previous pollen studies from the M & M mastodont show a transition from the Clovis-aged Drought to a more mesic environment.
Because Burrowing Owls (Athene cunicularia) often nest in colonies of prairie dogs (Cynomys sp.), recent declines of Gunnison's prairie dogs (Cynomys gunnisoni) could adversely affect this owl, considered uncommon in northern Arizona. In 2005, we determined the colony size and burrow density of 33 active Gunnison's prairie dog colonies in grasslands of northeastern Arizona. In 2006, we surveyed these colonies to determine the presence and relative abundance of Burrowing Owls, monitored nests to estimate nest success and productivity, and studied habitat characteristics at Burrowing Owl nest burrows. The 33 mapped colonies had a mean colony size of 16.6 ha and mean burrow densities of 57.7 active burrows/ha and 122.9 total burrows/ha. Seventeen nesting pairs of Burrowing Owls were associated with 12 of 33 (36%) prairie dog colonies, producing an average of 1.7 young per nest. Burrowing Owl presence at a prairie dog colony was not related to colony size or burrow density. Occurrence of an owl nest within a prairie dog colony was positively correlated with the mean number of active prairie dog burrows, total burrows, and percent of active burrows within 50 m, and negatively correlated with distance to the nearest active and inactive prairie dog burrow, elevation, and percent slope. Eight of 17 (47%) Burrowing Owl nests were successful, with brood size averaging 5.4 young per successful nest 25–31 days after hatching. Successful nests had fewer active, inactive, and total prairie dog burrows within 50 m than unsuccessful nests, contrary to previous findings. Successful nests also were closer to the nearest road than failed nests.
Oak savannas of the Southwestern Borderlands region provide food, cover, and sites for nesting, roosting, and perching for a diversity of bird species. The results of a five-year (2003–2007) study of bird species, numbers of birds, and their diversities in the naturally occurring (unburned) oak savannas of the region are reported in this paper. Effects of cool-season and warm-season prescribed burning treatments and a wildfire on bird species and numbers of birds sighted on the same study area after these burning events are also presented. These effects were difficult to isolate, however, because of the large variability in the tallies of bird species and numbers of birds obtained throughout the study.
The continued fragmentation of natural environments across the continent has raised concern about the ability of sensitive species and ecological communities to persist into the future. To explore the patterns and processes of fragmentation in an arid setting, the vertebrate species present on habitat fragments of various sizes were analyzed in the Sonoran Desert. Species densities, vegetation parameters, and landscape variables were recorded. Strong vegetation changes were correlated with fragment age. Vegetation changes on the fragments included increased grass cover with decreased shrub cover. These changes in vegetation parameters corresponded closely with decreases in abundance of several species that were commonly found on control sites.
Urban effects on wind patterns will become increasingly important as cities and the world's urban population continue to grow. Previous research has shown urban areas themselves can affect wind patterns both through their aerodynamic and thermal properties. This article examines wind speed changes in Phoenix, Arizona, and their relationship to temperature. I hypothesized that urban wind speeds increased over the study period of 1993–2008 and that wind speeds in the surrounding areas are also increasing, perhaps as part of an urban-rural thermal circulation. Correlation coefficients were used to measure the association between wind speed and temperature as well as the temporal trend in each variable over the study period for 24 meteorological stations in and around Phoenix. Significant changes in temperature over the study period were found for all stations and these tended to vary by month. Wind speed was found to have increased over the study period for most stations for most month/hour combinations. There is a distinct spatial pattern in these correlations. Finally, a diurnal pattern was found in the temperature vs. wind speed correlation coefficients for all stations. The results of this study tend to indicate increasing winds as Phoenix and its heat island continue to grow.