Browsing by Subject "Sand dunes"
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Item A comparison of the rodent faunas in sandhill habitats from the northern Chihuahuan Desert in Texas(2005-08) Brant, Joel G.; Phillips, Carleton J.; Jones, Clyde J.; Baker, Robert J.; Strauss, Richard E.; McIntyre, Nancy E.During the latter years of the twentieth century, scientists and naturalists began placing increasing emphasis on the importance of the world’s rich diversity of species. In keeping with this trend, biologists have increased their efforts to learn as much about the biodiversity of every environment and have demonstrated that the results of these efforts are essential to understanding how diversity is maintained in each environment. The objective of this study is to characterize the rodent communities inhabiting sand dune habitats at two protected areas in the northern Chihuahuan Desert. The sand dunes at each locality were divided into three dune habitats (cover sands, vegetated dunes, and active dunes) based on substrate stability and vegetative cover. Sampling was conducted in each of these dune habitats from November 2000 to August 2003 (Monahans Sandhills State Park) and October 2003 to February 2004 (Guadalupe Mountains National Park). Twenty-nine species of mammals were recorded from Monahans Sandhills State Park (MSSP) with Dipodomys ordii being the most abundant species. The sand dunes at Guadalupe Mountains National Park (GMNP) yielded 23 mammalian species with the most abundant species being Dipodomys merriami. Rodent diversity was significantly higher in sand dune areas than in the surrounding cover sands at both parks. Active dunes from both parks had significantly more species and were more diverse than the cover sands habitats. The habitat heterogeneity hypothesis is the most likely mechanism that accounts for these results and the maintenance of this level of biodiversity in sand dune environments.Item A comparison of the rodent faunas in sandhill habitats from the Northern Chihuahuan Desert in Texas(Texas Tech University, 2005-08) Brant, Joel G.; Phillips, Carleton J.; Jones, Clyde J.; Baker, Robert J.; Strauss, Richard E.; McIntyre, Nancy E.During the latter years of the twentieth century, scientists and naturalists began placing increasing emphasis on the importance of the world’s rich diversity of species. In keeping with this trend, biologists have increased their efforts to learn as much about the biodiversity of every environment and have demonstrated that the results of these efforts are essential to understanding how diversity is maintained in each environment. The objective of this study is to characterize the rodent communities inhabiting sand dune habitats at two protected areas in the northern Chihuahuan Desert. The sand dunes at each locality were divided into three dune habitats (cover sands, vegetated dunes, and active dunes) based on substrate stability and vegetative cover. Sampling was conducted in each of these dune habitats from November 2000 to August 2003 (Monahans Sandhills State Park) and October 2003 to February 2004 (Guadalupe Mountains National Park). Twenty-nine species of mammals were recorded from Monahans Sandhills State Park (MSSP) with Dipodomys ordii being the most abundant species. The sand dunes at Guadalupe Mountains National Park (GMNP) yielded 23 mammalian species with the most abundant species being Dipodomys merriami. Rodent diversity was significantly higher in sand dune areas than in the surrounding cover sands at both parks. Active dunes from both parks had significantly more species and were more diverse than the cover sands habitats. The habitat heterogeneity hypothesis is the most likely mechanism that accounts for these results and the maintenance of this level of biodiversity in sand dune environments.Item Deposition and stratification of oblique dunes, South Padre Island, Texas(1981-12) Weiner, Stephen Paul; McGowen, J. H.; Scott, Alan Johnson.Oblique dunes have orientations that are intermediate between those of transverse and longitudinal dunes. The oblique dunes studied are reversing dunes which undergo no net annual migration when associated with normal meteorological patterns. From April 1980 through September 1980, the dunes migrated up to 65 feet (19.8 m) northwestward under the influence of prevailing onshore winds. High velocity northerly winds (November 1980 through February 1981), associated with the passage of winter frontal systems, caused the dunes to rapidly migrate 65 feet (19.8 m) southward. Volumes of sand transported by these strong winds were commonly reduced by accompanying rainfall. In October 1980 and March 1981 neither wind direction was dominant, and frequent changes in wind direction caused many of the dunes to become flattened. Hurricanes, which strike the area in late summer, have had no lasting effects on the dunes. Three major stratification types were observed in trenches and on etched surfaces. Translatent strata were deposited by wind ripples; grainfall deposits accumulated when saltating grains settled on leeward slopes of the dunes, and grainflow cross-strata were developed by avalanching on leeward slopes. Preservation of these stratification types occurred in zones of net deposition, predominantly leeward of the dune crests. Strata deposited during the summer wind regime dip northeast, whereas the winter strata dip in a southerly direction. The winter deposits are best preserved in the central cores of the dunes. This suggests that either the high velocity winds of the initial winter frontal systems destroy large volumes of the summer deposits, or that the dunes migrate southward, under the influence of dry northerly winds, during droughts. Oblique dune deposits should be difficult to discern in the rock record, because they may contain aspects of either transverse or longitudinal dunes. It is likely that some ancient oblique dunes have been mistakenly described as other dune types in the literature.Item Geology of Sand Dunes, Lamb and Hale County(Texas Tech University, 1951-05) Green, Francis EarlNot Available.Item Use of fertilizer to increase vigor of sea oats and bitter panicum(Texas Tech University, 1972-08) Baker, Roger LynnNot available