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The geoheritage importance of the stones used in the construction of buildings in urban landscapes has been documented by several scholars around the world. Building stones can provide an ex situ cross-section of a region's geodiversity and illuminate its cultural significance. Research at the historic Maxey Homestead (1902–1907), located along the eastern escarpment of the Southern High Plains near Post, Texas, has uncovered a rock collection gathered from local sources. In addition, rocks from the eastern escarpment were used to construct and decorate a house in 1938 (~9 km to the north) after the Maxeys moved from their original homestead. A combination of GIS and 3D mapping using an unmanned aerial vehicle were used to assess and analyze the geodiversity significance of the rock collection and rock-decorated house. Rock collecting and the use of local stones in building construction provide insights into the geodiversity of the Southern High Plains' eastern escarpment and the historical geoheritage of northwest Texas in the early 20th century. The results of this study also demonstrate the importance of examining non-urban and historical landscapes for elucidating the significance of geodiversity to past peoples. [ABSTRACT FROM AUTHOR]

Aerial photogrammetry is increasingly being used to discover, document, and interpret the cultural heritage of landscapes. Information on the constructed cultural heritage left behind by the first cattle ranchers in the American West is being lost as the land is transformed and modified, and stewardship of the land changes across generations. An unmanned aerial vehicle (UAV) has been used in this research to record and interpret two surface water cattle tanks constructed by Texas cowboys in the mid-1880s. Similar size rocks have been used and placed in a similar pattern across the walls of both tanks. This similarity suggests both tanks were constructed at the same time. This research also demonstrates that UAV photogrammetry can be used to rapidly record and analyze the constructed cultural heritage of American West cowboys.

The geoheritage importance of the stones used in the construction of buildings in urban landscapes has been documented by several scholars around the world. Building stones can provide an ex situ cross-section of a region’s geodiversity and illuminate its cultural significance. Research at the historic Maxey Homestead (1902–1907), located along the eastern escarpment of the Southern High Plains near Post, Texas, has uncovered a rock collection gathered from local sources. In addition, rocks from the eastern escarpment were used to construct and decorate a house in 1938 (~9 km to the north) after the Maxeys moved from their original homestead. A combination of GIS and 3D mapping using an unmanned aerial vehicle were used to assess and analyze the geodiversity significance of the rock collection and rock-decorated house. Rock collecting and the use of local stones in building construction provide insights into the geodiversity of the Southern High Plains’ eastern escarpment and the historical geoheritage of northwest Texas in the early 20th century. The results of this study also demonstrate the importance of examining non-urban and historical landscapes for elucidating the significance of geodiversity to past peoples.

Aerial photogrammetry is increasingly being used to discover, document, and interpret the cultural heritage of landscapes. Information on the constructed cultural heritage left behind by the first cattle ranchers in the AmericanWest is being lost as the land is transformed and modified, and stewardship of the land changes across generations. An unmanned aerial vehicle (UAV) has been used in this research to record and interpret two surface water cattle tanks constructed by Texas cowboys in the mid-1880s. Similar size rocks have been used and placed in a similar pattern across the walls of both tanks. This similarity suggests both tanks were constructed at the same time. This research also demonstrates that UAV photogrammetry can be used to rapidly record and analyze the constructed cultural heritage of American West cowboys. [ABSTRACT FROM AUTHOR]

The eastern escarpment breaks of the Southern High Plains of Texas are both a geomorphic and ecotonal transition zone from the high plains surface to the Rolling Plains below. The geoarchaeological record on the Southern High Plains surface is well documented, but few studies have investigated the sediments, soils, and geochronology of the eastern escarpment. The current investigation has targeted the discontinuous remnants of Late Quaternary deposits within Spring Creek, a tributary within the upper Brazos River basin. A total of 19 profiles, core, and isolated exposure locations placed along a transect from Macy Fork through upper Spring Creek and 40 radiocarbon ages provide a composite sequence and geochronology that also documents the Late Pleistocene to Late Holocene paleoenvironments of this drainage. The resulting record illustrates a series of major changes in sediments and local habitats over the past ~11,550 radiocarbon years (13,469–13,390 calendar years), characterized primarily by reductions in available water and increasing aridity that peaked during the middle Holocene. This sequence provides significant context to an expanding record of Late Pleistocene to middle Holocene biota and cultures. Subsequent downcutting of the drainage post-6000 14C yr B.P. (6988–6744 calendar years) removed large sections of the depositional sequence. Local topography within Spring Creek drainage greatly impacted the preservation of these deposits. The remaining record provides some different insights than those available from the Southern High Plains record.

Drought is defined, experienced, and communicated about in multiple ways. This case study examines individual definitions of drought (timing, impacts, and severity) and attitudes about climate change. Household surveys (n = 120) were conducted in Cimarron County, Oklahoma and Union County, New Mexico using a stratified random sampling method to select farmers, ranchers, and town residents. Information about drought is primarily communicated between neighbors, friends, and family, as well as media and local governing agencies. Residents perceive the recent drought to be the worst drought on record, regardless of previous drought experiences. Residents reported widespread drought-related impacts on agriculture, environment, and society. Most residents see drought as cyclical and driven by natural causes, rather than human causes. We recommend adaptive drought communication engage more fully with identity, place, and history. Climate information should be presented in a relevant manner to diverse agricultural stakeholders with differing attitudes about climate change, management, and climate information. [ABSTRACT FROM AUTHOR]

Abstract Playas are the often most noticeable surface water feature in the Southern High Plains. The purpose of our study is to provide local and timely reference data on playa water quality and quantity in drier and wetter weather conditions. Water quality parameters of three playas in Texas, in the summer of 2016, were monitored via weekly environmental sampling. Annual water volume-depth dynamics within the study playas were also estimated by water balance informed by climate and geospatial data. The results showed that both direct rainfall and runoff affect the volume of water within the playa where the volume of runoff entering into a playa is contingent upon the surrounding drainage area. In addition, water quality does vary substantially from playa to playa (conductivity 180–850 μS/cm, TOC 13–81 mg/L) and between playa and non-playa surface water. Differences were related to local soils, drainage area size/slope, and land use. It was also found from the water quality analysis that playas are capable of containing a quality of water that would make them an attractive habitat for wildlife. The greatest economic value of playas may be their ability to contain high quantities of biodiversity though the future of their capacity to do so is uncertain. Graphical abstract Unlabelled Image Highlights • Size of the drainage area controls how much water is found in West Texas playas. • It is plausible that the water quality within one playa is different from another. • The water balance predicts likely behavior of other playas in the region. • External sources, biological activity, and evaporation all control water quality. • It is highly probable that playa water can be consumed by local species. [ABSTRACT FROM AUTHOR]

The imminent depletion of the Ogallala Aquifer demands innovative cropping alternatives. Even though the benefits of cover crops are well recognized, adoption has been slow in the Southern High Plains (SHP) of the United States because of concerns that cover crops withdraw soil water to the detriment of the summer crops. This small plot experiment tested the interacting effects—production, soil water depletion of the cover crops, and subsequent teff [Eragrostis tef (Zucc.) Trotter] summer hay crops—of irrigation and tillage management with five cover crop types to identify low-risk cover crop practices in the drought-prone SHP. Dryland rye (Secale cereale L.) produced modest forage biomass (>1000 kg ha−1), even in a dry year, but it was found that light irrigation should be used to ensure adequate forage supply (>1200 kg ha−1) if winter grazing is desired. No-till management and timely termination of the winter cover crops were crucial to reducing the negative impact of winter crops on summer teff production. The results indicated no detriment to soil water content that was attributable to planting no-till cover crops compared with the conventional practice of winter fallow. Therefore, producers could take advantage of the soil-conserving attributes of high-quality winter forage cover crops without experiencing significant soil water depletion.

The eastern escarpment of the Southern High Plains (USA) is today a semi-arid erosional landscape delineated by canyon breaks and topographic relief. A series of buried soils were identified, described, and sampled at 19 soil profile localities exposed along terraces of the South Fork of the Double Mountain Fork of the Brazos River (South Fork) and two associated tributaries (Spring Creek and Macy 285 drainage). Radiocarbon dating revealed late-Pleistocene to early Holocene (~12,580–9100 14C B.P.), middle-Holocene (~6025–4600 14C B.P.), and late-Holocene (~2000–800 14C B.P.) buried soils. The late-Pleistocene to middle-Holocene soils were preserved only at higher elevations within the upper section of the South Fork and Spring Creek. A topographic position analysis was conducted using GIS to identify and examine the impacts of a soil topographic threshold on the preservation and distribution of buried soils within this geomorphic system. Above the identified ~810 m threshold, lateral migration of channels was constrained. Extensive channel migration below the threshold removed older terraces that were replaced with late-Holocene terraces and associated buried soils. Landscape topography constraints on geomorphic processes and soil formation impacted the preservation of archaeological sites in this semi-arid region.

We used the lesser prairie‐chicken (Tympanuchus pallidicinctus), an iconic grouse species that exhibits a boom–bust life history strategy, on the Southern High Plains, USA, as a bioindicator of main and interactive effects of severe drought and grazing. This region experienced the worst drought on record in 2011. We surveyed lesser prairie‐chicken leks (i.e., communal breeding grounds) across 12 years that represented 7 years before the 2011 drought (predrought) and 4 years during and following the 2011 drought (postdrought). Grazing was annually managed with the objective of achieving ≤50% utilization of aboveground vegetation biomass. We used lek (n = 49) count data and covariates of weather and managed grazing to: (a) estimate long‐term lesser prairie‐chicken abundance and compare abundance predrought and postdrought; (b) examine the influence of annual and seasonal drought (modified Palmer drought index), temperature, and precipitation on long‐term lesser prairie‐chicken survival and recruitment; and (c) assess and compare the influence of grazing on lesser prairie‐chicken population predrought and postdrought. Lesser prairie‐chicken abundance was nearly seven times greater predrought than postdrought, and population declines were attributed to decreased survival and recruitment. The number of days with temperature >90th percentile had the greatest effect, particularly on recruitment. The population exhibited a substantial bust during 2011 and 2012 without a boom to recover in four postdrought years. Adaptive grazing positively influenced the population predrought, but had no effects postdrought. Results suggest that the severe drought in 2011 may have been beyond the range of environmental conditions to which lesser prairie‐chickens, and likely other species, have adapted. Land management practices, such as grazing, should remain adaptive to ensure potential negative influences to all species are avoided. Increasing habitat quantity and quality by reducing habitat loss and fragmentation likely will increase resiliency of the ecosystem and individual species. We used the lesser prairie‐chicken (Tympanuchus pallidicinctus), an iconic grouse species that exhibits a boom–bust life history strategy, on the Southern High Plains, USA, as a bioindicator of main and interactive effects of severe drought and grazing. The population exhibited a substantial bust during 2011–2012, primarily through reduced recruitment due to excessive heat, without a boom to recover in four postdrought years. Adaptive grazing positively influenced the population predrought, but had no effects postdrought. [ABSTRACT FROM AUTHOR]

Cattle ranching is an important part of the heritage of the American West, yet few archaeological studies focus on this industry. Many aspects of ranching-related work are ephemeral, leaving on the landscape only small traces of these past activities. Survey on an historical ranch (established 1882) along the eastern escarpment of the Llano Estacado has identified a short-term cowboy camp at Macy Locality 16 (41GR722). Metal-detector survey and excavation has delineated camping activities alongside a chuck wagon and the remains of a temporary corral. Historical documents, composition of the site’s artifact assemblage, and its position on the landscape indicate the occupation was a ca. 1882-1901 roundup camp. This study demonstrates the importance of contextualizing ephemeral ranching-related sites within the broader organization of ranching activities across the landscape. [ABSTRACT FROM AUTHOR]

Groundwater reliant and agriculturally dominant environments (GRADEs) utilize exhaustible aquifer resources to supply food and fiber demands. The sustainability of these GRADES is threatened by over‐exploitation of fresher groundwater resources. There is an interest in exploring deeper brackish groundwater resources to sustain agricultural based economies in these regions. Using the southern high plains of Texas (SHP) as a test‐bed, the interlinkages between food‐energy‐water on improving water resiliency through brackish groundwater development is explored. Three scenarios—(1) direct use of deeper formations; (2) blending deeper and shallower groundwaters and 3) desalination of blended resources were evaluated in a spatially explicit manner. The results indicate that direct reuse of deeper water is possible over 30% of the study area, but it is not available in areas of critical need. The parameters limiting the suitability of deeper groundwater for agriculture in the order of decreasing importance are EC > TDS > SAR > B > Na > Cl. Simple blending of water from deeper and shallower aquifers improve water quality over roughly 900,000 acres. While blending greatly reduces the specific ion toxicities caused by sodium absorption ratio (SAR) and boron (B), the limitations of total dissolved solids (TDS) cannot be overcome. The over‐burden pressures in the deeper confined aquifer somewhat alleviate the blending energy requirements, especially in the southern portions of SHP. Desalination increases the energy requirements by several fold and is not suitable to sustain current agricultural practices which are focused mostly on lower valued staple crops. Using desalinated water for municipal and industrial uses can help ameliorate the stresses on the Ogallala Aquifer and enhance its longevity. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 21–36, 2018 Novelty or Significance: The study is focused on the linkages between food, energy and water in groundwater dependent agricultural economies. Using the Southern High Plains of Texas as a test‐bed, the work evaluates whether a deeper brackish groundwater resource (Dockum geological unit) can be used to augment water supplies to sustain intensive agricultural production. The study identifies various factors that limit the use of this deeper resource and quantifies the energy footprint associated with three progressively complex approaches to improve water resiliency in the region and prolong the life of the Ogallala Aquifer. [ABSTRACT FROM AUTHOR]

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Playa wetlands, the dominant hydrological feature of the semi-arid U.S. High Plains providing critical ecosystem services, are being lost and degraded due to anthropogenic alterations of the short-grass prairie landscape. The primary process contributing to the loss of playas is filling of the wetland through accumulation of soil eroded and transported by precipitation from surrounding cultivated watersheds. We evaluated effectiveness of vegetative buffers surrounding playas in removing metals, nutrients, and dissolved/suspended sediments from precipitation runoff. Storm water runoff was collected at 10-m intervals in three buffer types (native grass, fallow cropland, and Conservation Reserve Program). Buffer type differed in plant composition, but not in maximum percent removal of contaminants. Within the initial 60 m from a cultivated field, vegetation buffers of all types removed >50% of all measured contaminants, including 83% of total suspended solids (TSS) and 58% of total dissolved solids (TDS). Buffers removed an average of 70% of P and 78% of N to reduce nutrients entering the playa. Mean maximum percent removal for metals ranged from 56% of Na to 87% of Cr. Maximum removal was typically at 50 m of buffer width. Measures of TSS were correlated with all measures of metals and nutrients except for N, which was correlated with TDS. Any buffer type with >80% vegetation cover and 30–60 m in width would maximize contaminant removal from precipitation runoff while ensuring that playas would continue to function hydrologically to provide ecosystem services. Watershed management to minimize erosion and creations of vegetation buffers could be economical and effective conservation tools for playa wetlands. [ABSTRACT FROM AUTHOR]

With the increased use of fungicides in cultivated regions such as the southern High Plains (SHP), U.S., unintentional runoff and drift as well as direct overspray during aerial application lead to environmental exposures that may influence soil microbial communities and related biogeochemical functioning. Our goal was to examine the effects of two popular fungicides Headline® (pyraclostrobin) and Quilt® (azoxystrobin/propiconazole) on respiration from soil microbial communities in playa wetlands embedded in cropland and native grassland and their adjacent watersheds. We monitored fungicide effects (at levels of 0, .1 ×, 1 × and 10 × the label rate) by measuring respiration from plant matter amended soils collected from 6 cropland and 6 grassland playas and uplands. In addition, differences in microbial community structure among land use types were determined by measuring ergosterol levels in cropland and native grassland playas and uplands. Native grassland playas and their associated watersheds had up to 43% higher soil respiration rates than cropland playas and watersheds, indicating higher soil microbial activity. Application of either fungicide had no effect on soil respiration at any concentration in either land use type or habitat type (playa/watershed). Native grassland playas and watersheds had 3 and 1.6 times higher ergosterol content than cropland playas and watersheds. The lack of soil respiration response to fungicide application does not necessarily suggest that fungicides used in this study do not affect non-target soil microbial communities due to potential compensation by other biota. Future studies should further elucidate existing microorganism communities in playas and their watersheds. [ABSTRACT FROM AUTHOR]

The article discusses a study on the migration and habitat preferences of Swainson's hawk at a stopover site for foraging in northwestern Texas in autumn. It notes in the results that the most favored habitat type of these raptors was the harvested silage corn fields which exposes invertebrates and small mammals to predation during harvest. It also suggests in this study that these raptors use this area as a refueling site due to its abundance in invertebrate prey before embarking on their long journey to southern America.

We quantified changes in long-term Snowy Plover (Charadrius nivosus) survey counts and return rates, estimated current sex and age-specific apparent survival and encounter rates, and calculated recruitment thresholds needed to maintain a stable population in the Southern High Plains of Texas. Mean survey counts of adult Snowy Plovers decreased by 78% at one saline lake (from 80 adults/survey to 18 adults/survey) from 1999-2000 to 2008-2010 but remained consistent at an alternate lake (from 45 adults/survey to 41 adults/survey). Adult and juvenile return rates have similarly declined within this time frame by 25 and 62%, respectively. Long-term declines in return rates may be the result of increased mortality from declining habitat conditions either within or outside the breeding season. Current estimates of adult (65%) and juvenile (12%) apparent survival are lower than most other estimates for Snowy Plovers throughout their range. Current estimates of adult and juvenile apparent survival and return rates indicate 5.8-10.0 hatchlings per adult per year are needed to maintain the current population without immigration, a 3-5 fold increase in the past 10 years. [ABSTRACT FROM AUTHOR]

Abstract: A concentration of lake/playa basins occurs on the Southern High Plains (SHP) of northwest Texas and eastern New Mexico. Associated with these lake/playas are lee-side lunettes positioned on their southeast margins ranging in height from 1.5 to >10 m. An OSL dating program was applied to 30 samples from lunettes associated with large lakes and small playa basins. Samples were extracted from trenched dune sections or from deep cores. Earlier SHP lunette investigations show depositional ages primarily in the late Wisconsin and Holocene. This research extends the timing of lunette accretion to the middle Pleistocene, the earliest recorded deposition for these features. The expanded chronology permitted investigation into dune morphology on nested lunettes built on contracting lake margins. Outer lunettes formed prior to inner dunes, but simultaneous deposition occurred on downwind ridges as younger lee-side dunes were constructed. Large lake lunettes were inactive during discreet SHP pluvial episodes from early Wisconsin to LGM. Conversely, these lunettes accreted when climatic conditions promoted basin desiccation and aeolian deflation. This suggests their mode of formation contrasts with lunette models recognized for other regions. From post LGM to earliest Holocene, active lunette accretion occurred from 16 to 11 ka followed by a significant period of lunette construction during the mid-Holocene. Late Holocene-lunette deposition was interrupted by intervals of landscape stability. Lunette deposition between 1300s and 1700s corresponds with drought intervals recognized in tree-ring records from adjacent regions. Recent lunette activity on the plateau is contemporary with the 1930''s ‘dust bowl’. Further insight into SHP response to changing climatic conditions was given by comparing lunette depositional events with previous investigations on sedimentation intervals for draws, lake/playa basins, and sand sheets. [Copyright &y& Elsevier]

Abstract: Guayule has long been known as a potential source of natural rubber. Native guayule populations are scattered throughout 300,000km2 of rangeland in the Chihuahuan Desert of Texas and Mexico. The only native indigenous U.S. stands occur in the Trans Pecos region of southwest Texas, and represent the most northern extension of the plant''s habitat. Maximum air temperatures of over 38°C are frequent and minimum temperatures of −23°C have been recorded. Guayule has been successfully cultivated across the arid and semi-arid Southwestern U.S., but new production areas need to be identified in order to meet the expected world-wide shortage of natural rubber by 2020. The objective of our study was to determine if guayule production could be successful farther north on the Southern High Plains near Halfway, TX. Guayule seedlings were transplanted May 18, 2006 at the Texas AgriLife Research Station at Halfway. Seed used included four released lines, AZ-1, AZ-2, AZ-3, and AZ-4; a released USDA cultivar (11591); and three unreleased breeding lines, N9-3, N6-5, and N13-1. Guayule cold damage was estimated in June of 2007 and 2008 using the following index: (1) no damage, (2) slight – injury of terminals to 6cm, (3) moderate – 2/3 of plant volume injured, (4) severe – all aerial portions killed but resprouting, and (5) complete – beyond recovery with no regrowth. Plant harvests were conducted in April 2008 and March 2009. Following the 2006/2007 winter the cold damage index ranged from 1.2 in 11591 to 3.8 in AZ-1. The minimum air temperature was −15°C. There was minimal cold damage during the 2007/2008 and 2008/2009 winters. Biomass of the 24 month-old shrubs harvested in 2008 varied from 9639kg/ha in 11591 to 13,393kg/ha in AZ-4. Shrub biomass in 2009 ranged from 26,721kg/ha in 11591 to 32,951kg/ha in N6-5. Rubber yield in 2008 was 222 and 639kg/ha in AZ-3 and N6-5, respectively. Line AZ-3 yielded 717kg/ha of rubber in 2009 while line AZ-4 yielded 2006kg/ha. The critical factor in winter survival appeared to be the temperature regime that existed in the late fall and early winter: a gradual and progressive onset of low temperatures that allowed the shrubs to be dormant when freezing temperatures occurred. Lines 11591 and N6-5 had the least cold damage and hold promise for establishment and rubber production on the Southern High Plains of Texas. Certain production criteria make this area an ideal guayule production site: the long-term annual rainfall averages 460mm, irrigation water salinity is less than 1 E.C. and is pumped from only 90m, and center pivot sprinklers are available for establishing guayule by direct-seeding. [Copyright &y& Elsevier]

Abstract: Presently stabilized Southern High Plains (SHP) dune systems have been repeatedly re-activated during the past 200,000years, providing an archive of environmental and related climatic change for the late Quaternary. Our data set of 38 optically dated samples from four different localities identifies eolian activity from late-middle Pleistocene to the historic period. Oldest eolian sediments are from the Blackwater Draw Formation and indicate accretion during late-middle to late Pleistocene. Younger sediments dating from the later Pleistocene through the Holocene are found in the Muleshoe, Lea-Yoakum, Mescalero, and Monahans dunes that overlie the Blackwater Draw Formation. Muleshoe dunes accreted during the Late Pleistocene between 31±3 and 27±2ka, while Holocene deposition transpired 7.5±0.4, 4.0±0.7ka through 3.6±0.4ka, and between 1.3±0.2 and 1.1±0.1ka. A period of dune building for Lea-Yoakum dune sediments occurred during the late Pleistocene (48±5ka), and the later Holocene (3.6±0.4ka). Mescalero and Monahans dunes were accreting during the later Pleistocene between 29±3 and 22±2ka followed by a sequence of eolian sand deposited ca. 15ka. Holocene eolian sedimentation for the Mescalero and Monahans dunes occurred 7.5±0.8, 5.1±0.5, 4.3±0.4, and 2.0±0.3ka. Historic eolian deposition is identifiable in the dune chronology with multiple optical age estimates overlapping established drought events recorded ca. 1890, 1910, 1920, and during the 1930’s when the North American “Dust Bowl” transpired. These Quaternary eolian deposits mantling the Southern High Plains are an important component of the surficial material of the region and provide a rich archive of past climatic change. [Copyright &y& Elsevier]

Lithology and geologic structure of a paleochannel in the Southern High Plains aquifer were tested for possible influence on source water mixing that has been implicated in the alteration of water types within the Southern High Plains aquifer. Geochemical and physical data suggested changes to source-water mixing across short distances in the Southern High Plains aquifer as a result of location relative to a paleochannel center. Changes in saturated thickness because of changes in elevation of the aquifer base layer from paleochannel incision appear to be an important influence on water composition. The thicker saturated interval of the aquifer near the paleochannel center minimizes geochemical influences from smaller volume source waters such as agricultural recharge and cross-formational flow that differ in composition compared to the more dominant natural recharge from concentrated surface flow. The thinner saturated thicknesses of the paleochannel bank and paleohighland areas allow geochemical changes in source waters to be visible in mixed groundwater samples. Examination of the water columns through resistivity and temperature indicates stratified layers that corresponded to the three major source waters that were implied by the variable geochemical signal of the mixed groundwater samples. Changes in lithology along the paleochannel did not appear to influence the contribution of cross-formational flow as warmer, more conductive water was present across the site in the lowermost layer of the stratified aquifer. The influence of agricultural recharge appeared highly variable with strong differences in groundwater composition in the paleohighland area near large agricultural areas. [ABSTRACT FROM AUTHOR]

Playas are the primary habitats for amphibians in the Southern High Plains, USA. Spadefoot toads ( Spea spp.) are the dominant amphibian species; their demographics, body size, and immunology have been altered in playas in cropland relative to native grassland landscapes. To further understand cultivation effects on spadefoots, we compared percent body lipids and fatty acid profiles of S. bombifrons and S. multiplicata among tadpoles, metamorphs, and post-metamorphic juveniles in cropland versus grassland playas. Generally, tadpoles of both species had lower percent lipids than metamorphs and juveniles. Percent lipids were influenced by cultivation only in S. multiplicata; tadpoles contained more lipids in cropland than grassland playas. Sum of all fatty acids in S. bombifrons increased after metamorphosis regardless of landscape. However, fatty acids in S. multiplicata were similar among stages in cropland whereas in the grassland habitat juveniles had increased levels compared to tadpoles and metamorphs. In both species, saturated fatty acids decreased after metamorphosis. Mono- and polyunsaturated fatty acids generally remained steady or increased after metamorphosis. However, polyunsaturated levels were lower in S. bombifrons tadpoles and S. multiplicata tadpoles and metamorphs in cropland than grassland playas. Thus, cultivation may be affecting nutritional profiles in these species with associated fitness consequences. [ABSTRACT FROM AUTHOR]

Lithic analysis on the southern High Plains traditionally has focused on behavioral inferences based in part on the geographic relationship between disparately distributed high quality toolstone sources. These sources often are used as a proxy for behavior by which hunter-gatherer mobility within the wider region can be modeled based on the presence or absence of specific material types within any one assemblage. In contrast, utilization of secondary lithic material sources, such as the alluvial gravels, has received relatively little attention. The corollary of this research tradition is that hunter-gatherer resource scheduling strategies appear to be highly structured and necessarily dependant on logistical trips to the high quality toolstone locations. Two sites used for extensive procurement of Ogallala Formation gravels provide an opportunity to examine the range of material available to hunter-gatherer groups at locations between the high quality sources. Characterization and technological analysis of these secondary sources has been achieved through systematic sampling to record the variability in lithic source material, technology, and geomorphic processes. The results are significant for the interpretation of lithic technology at this location and for the wider understanding of hunter-gatherer populations moving through the rich resource areas at the edge of the southern High Plains. [ABSTRACT FROM AUTHOR]

Citizen science holds the potential and capacity to change the role of science in the face of current and impending environmental sustainability challenges. However, the sustainability science community must also address the ethical challenges inherent in the nature and outcomes of citizen participation and inclusion. In this article, we provide a brief history of Participatory Action Research (PAR), long popular in the social sciences, and explain how participatory methods can inform the process and products of citizen science to meet the dueling ideals of ethically engaging communities and producing more robust science. Our decade of human-environment research on drought resilience and adaptation in the Southern High Plains of the United States illustrates how PAR complements formal science and can contribute to community resilience and adaptation efforts. Synthesized into 10 entry points for more ethical and participatory science, our semi-chronological narrative offers concrete strategies informed by PAR principles and values, at various stages of research, and highlights the place-based, ethical, and methodological contexts for applying each strategy. [ABSTRACT FROM AUTHOR]

The article discusses a study which documented the migration chronology of 15 waterfowl species using playa wetlands in the Southern High Plains of Texas from February 2004 through April 2006. The researchers observed 23 waterfowl species on playas and migration chronology was quantified for eight species of dabbling ducks and two species of geese. A chart is presented that lists the number of waterfowl observed using 58 playa wetlands. It was found that all dabbling ducks, except Blue-winged Teal, could either be described as having bimodal or unimodal migration patterns.

Abstract: Playas are small, circular basins forming a ubiquitous component of the southern High Plains landscape. They are filled with carbonaceous mud deposited since the terminal Pleistocene. The stratigraphy and geochronology of 30 playas was investigated to better understand the paleoenvironmental record of basin filling. At the base of the fill in some playas is a well sorted eolian sand dated between ~13,000 and ~11,000 14C yr BP. The beginning of mud deposition, representing aggradation of eolian dust on a moist, vegetated playa floor was largely between ~12,000 and ~10,500 14C yr BP. Playa filling slowed ~9000 to ~4000 14C yr BP, probably due to dry conditions, increased ~4000 to ~2000 14C yr BP, then slowed again. Eolian sand and loam, likely representing regional aridity, accumulated in some basins episodically just prior to ~10,700 14C yr BP, between ~8600 and ~4700 14C yr BP, and at ~1300 14C yr BP. Stable C isotopes from one basin indicate that the playa was inundated only seasonally throughout the record beginning ~11,500 14C yr BP. The phytolith record in that basin indicates an abrupt shift toward cooling ~11,400 to ~11,200 14C yr BP and then increasing importance of xeric-adapted C4 grasses through the Holocene. [Copyright &y& Elsevier]

Preservation decisions often have to be made regarding the long-term status of deeply buried sites. However, the opportunity to evaluate these decisions practically, decades later, is rare. The Nash site, on the Southern High Plains of the USA, is one site where reinvestigation has permitted the assessment of a well-stratified site after an intervening period of thirty years during which it was impacted by dredging and impoundment. The current condition of the site has generated challenges in both recovery and conservation of material. Renewed fieldwork at the Nash site highlights the need to evaluate preservation options while critically considering the effects of geomorphic, taphonomic, and cultural processes. [ABSTRACT FROM AUTHOR]

Late Paleoindian typology on the southern High Plains has suffered from overlapping definitions and subjectivity in assigning individual projectile points to types. To address perceived projectile point variability in the region, assemblages from several localities on the southern High Plains are examined for statistical differences in shape. Digital photographs of projectile points are used to digitize point outlines. Landmark coordinate data then are used to delineate 10 interlandmark characters. Multivariate analysis of projectile points from eight assemblages reveals that the primary difference in point shape lies between long points with narrow bases and short points with wide bases. Analysis of characters by raw material type or source discerned no significant differences. Variation in point form represented by most of the assemblages, including the Plainview and Milnesand type assemblages, overlaps to a significant degree. The Lubbock Lake FA5-17 assemblage, consisting of long points with narrow bases, appears most distinct in terms of shape and raw material selection indicating the contemporaneity of different point forms and perhaps technological traditions in the region by approximately 10,000 years ago. [ABSTRACT FROM AUTHOR]

Survey and testing results on the southern High Plains suggest that the material traces of prehistoric camp activity most likely are encountered in upland contexts. These sites are often either exposed on the modern ground surface or are only shallowly buried Localized thermal features (such as hearths), often represented by hearthstone scatters, are the most commonly encountered prehistoric structural components recorded at such sites. A series of replicative experiments has been conducted in order to understand further the site formation processes acting on these site assemblages. The results of this limited program record a significant relationship between size, potential for loss, and horizontal displacement from the discard location for both flaked lithic and hearthstone specimens. Displacement is primarily the result of cultural processes operating on the assemblage during data collection. Morphologically, hearthstones undergo significant post-depositional structural transformation, while an experimental hearth itself remained largely structurally intact. The results highlight the complexity of interpreting cultural and natural signatures in this highly dynamic and often fragile depositional environment. The program has been successful in the development of a simple straightforward procedure that appears useful for understanding site formation processes for upland sites on the southern High Plains and may be useful for semiarid to arid settings. [ABSTRACT FROM AUTHOR]

Abstract: The Southern High Plains of North America is rich in archaeological sites, but many are not well constrained chronologically, owing to a lack of material for radiocarbon dating. A program of optically stimulated luminescence (OSL) dating, applying mainly single-grain analyses, was therefore initiated. Many samples have independent age estimates from radiocarbon to check the OSL results, but OSL age estimates are also provided for those sites that otherwise lack secure chronological control. Sediment samples for OSL were obtained primarily from Paleoindian and Archaic localities, though include deposits of more recent age. Through the analysis of single grains, equivalent dose—the numerator of the age equation—is evaluated independently on numerous grains. The distribution of these values is relatively broad for some samples, and this is attributed to post-depositional mixing. Mixing is also evident in some samples with more narrow distributions. Selecting portions of the mixed distributions for age determination allows more accurate dating for some samples, but the nature of the distributions limits the resolution on others, conclusions that cannot be as easily drawn from multi-grain analysis. Where independent age control is available, most OSL results broadly conform; however, some samples show discrepancies that are not readily explained, but may relate to association or dose rate problems. This underscores the desirability of obtaining where possible suites of chronological evidence. [Copyright &y& Elsevier]

Scaled quail (Callipepla squamata) populations have been declining since the early 1960s, and there is no clear understanding of what is causing this decline. It has been suggested that reproductive failure is a probable cause of this decline. We used radiotelemetry to evaluate nesting ecology and survival of scaled quail in the Southern High Plains of Texas in 1999 and 2000. We radio- marked 138 hens (66 in 1999 and 72 in 2000) and reported nesting activity on 106 nests. In 1999, 50 nests were detected with a nesting success of 44%. In 2000, 56 nests were detected with a nesting success of 64%. Chick survival was recorded at 21 days posthatch and was analyzed as present or absent, as exact numbers were difficult to determine. Two hens had chicks present at 21 days in 1999, but 16 hens had chicks present at 21 days in 2000. Chick presence with the hen at 21 days was negatively associated with cool and wet weather. Logistic regression revealed predictive relationships for models describing vegetation characteristics at and around nest sites as predictors of nesting success and nest sites. Variables in the models included percentage of bare ground, forb diversity, and amount of visual obstruction at different heights. Hen survival, nesting success, and chick survival were higher in 2000 than in 1999. Differences in vegetation composition and structure were likely responses to differences in precipitation between years. Drought and overgrazing by livestock increase the percentage of bare ground and reduce visual obstruction; these are likely contributors to the reduced scaled quail populations in the Southern High Plains. [ABSTRACT FROM AUTHOR]

Abstract: Clay lamellae are ubiquitous features in sands in a wide variety of settings around the world. Most studies of lamellae focus on: 1) a few or individual locales or on 2) formation by experimental methods in the laboratory. This study reports on lamellae from eight localities in three late-Quaternary dune fields on the Southern High Plains of northwest Texas and eastern New Mexico. Most lamellae observed are illuvial and they increase in number and thickness through time. A few (1–3) thin (1–2 mm) lamellae formed in Historic sediments. Lamellae are more numerous (3–12) and thicker (3–5 mm) in older late Holocene (< 1000 14C years BP) and middle Holocene (< 7600 14C years BP) sands. Soils that formed through the late Pleistocene and into the early Holocene (14,300–7600 14C years BP) or soils that formed throughout the Holocene can exhibit as many as 30 lamellae or lamellae of 10–12 mm thickness. The micromorphology of the lamellae shows that argillans on sand grains are thicker, more laminated, more continuous, and cap and link more grains through time. Other variables affect lamella morphology. Within individual dunes, the lamellae are best expressed where the sand is thickest; they decrease in number and thickness as sand thins. The lamellae also form only in clean, well-drained sand. Poor drainage and/or bioturbation result in formation of a continuous argillic horizon encasing lamellae. [Copyright &y& Elsevier]

Excavations at Mustang Springs, Texas, a key freshwater source on the Southern High Plains, have produced archaeological components of various ages, dating back to Paleoindian times. This report details a Historic fauna from the site that contains both native wild (bison, coyote) and domesticated (cattle, horse, sheep) species. Radiocarbon dates on the fauna fall into three age groups: modern, 100 B.P, and 280 B.P The assemblage is resting on a stratigraphic unconformity and shows evidence of post-depositional fluvial re-working and animal trampling, but was buried rapidly enough that the bone otherwise displays little evidence of surface weathering or carnivore action. The assemblage appears to represent an autochthonous fauna that accumulated gradually around the edge of a water hole, primarily by means of natural attrition. However human action in the form of domestic management of cattle and sheep, and perhaps bison hunting, is also evidenced. Whether these bison were among the last of the Southern Plains bison herd killed by commercial hide hunters—as is known to have occurred near this locality—cannot be determined from the available evidence. [ABSTRACT FROM AUTHOR]

Northern bobwhites (Colinus virginianus) are captured routinely for scientific study. Extreme exertion during restraint and transport can lead to acidosis and free radical production that result in muscle tissue damage. This condition, termed capture myopathy, can result in dyspnea, hyperthermia, weakness, muscle rigidity, and collapse. These complications could lead to increased susceptibility of individuals to predation or contribute to death weeks or months after capture. Death caused by capture could negatively bias mortality rate estimates if mortalities occur after traditional censor periods. We hypothesize that muscular damage incurred during capture handicaps northern bobwhites. We evaluated our hypothesis by comparing survival of northern bobwhite that were treated for muscular damage with an injection of vitamin E and selenium, a solution recommended in veterinary avian medicine, with bobwhites that were not treated. We captured northern bobwhite during 2002 and 2003 and injected half of the birds with 0.1 ml of a vitamin E and selenium solution and the other half with a saline control. We then transported these birds to our study site and monitored them using radiotelemetry. We estimated survival rates using the staggered-entry Kaplan-Meier Product Limit Estimator. The survival of treated birds was greater than the survival of control birds in 2002 at days 45 (58% vs. 29%, Z = 1.98, P = 0.05) and 66 (53% vs. 29%, Z = 1.79, P = 0.07), a period before and after which sample sizes were very small. Treated birds exhibited a greater (χ² = 7.11, P < 0.008) survival curve than control birds during 2003 and when treatments were pooled by year (χ² = 4.19, P = 0.04). Thus, our data suggest that injection of wild northern bobwhite with vitamin E and selenium increased survival of transplanted birds as compared to control birds injected with saline. [ABSTRACT FROM AUTHOR]

Agricultural land use may indirectly affect the body size of amphibians by altering the hydroperiods of nearby wetlands and influencing amphibian densities—both factors which can limit the larval and postmetamorphic growth rates of amphibians. We measured postrrietamorphic body size for 4 species (Spea multiplicata, S. boinbifrons, Bufo cognatus, Ambystoma tigrinum mavortium) and 3 age classes (metamorph, subadult, adult) of amphibians captured at playa wetlands surrounded by one of 2 general land-use types (cultivation, grassland) in the Southern High Plains. Sixteen playas (4 per land-use type in 1999 and 2000) were partially enclosed with drift fence and pitfall traps, and mass and snout-vent length (SVL) were measured from a subsample of captured individuals. Mass and SVL were 10-148% greater for amphibians captured at grassland wetlands than at cropland wetlands for most species and age classes. Mass and SVL also were 3-124% greater in 1999 than in 2000 for most species and age classes. We attribute differences in body size between land-use types to differences in the hydroperiods of the associated wetlands, and potentially to variation in the density of terrestrial conspecifics and aquatic predators. We attribute differences in body size between years to differences in rainfall. Body size is positively related to the probability of survival, reproduction, and evolutionary fitness in amphibians. Thus, if cultivation of landscapes surrounding wetlands negatively influences postmetamorphic body size of amphibians, restoration of native grasslands surrounding playa wetlands may help prevent local amphibian declines. [ABSTRACT FROM AUTHOR]

Breeding-bird communities inhabiting northern prairie wetlands have been shown to have higher densities and diversities in wetlands with a well-interspersed 50:50 vegetative cover:water ratio than in those wetlands with a higher or lower proportion of cover. Potential reasons for such a response include increased food or visual isolation and spacing of breeding birds. We manipulated cover:water ratios (75:25, 50:50, 25:75) in Southern Great Plains playas and examined avian response (i.e., species richness, nonwaterfowl bird density, and waterfowl density) to these patterns in winter. We found the highest species richness and generally the highest waterfowl densities in the 50:50 cover:water treatment. Because the amount of vegetative food was similar among treatments and waterfowl inhabiting playas during winter are forming pair bonds, it is most likely that the optimal edge and visual isolation provided in the 50:50 cover:water treatment contributed to its high use and richness. Nonwaterfowl bird density was not different among the treatments. Many nonwaterfowl birds using playas in winter, such as McCown's longspur (Calcarius mccownii), occur as nonbreeding feeding flocks, are not forming pair bonds, and likely are not responding to particular cover:water treatments. Playa wetland biologists should create a well-interspersed 50:50 cover:water ratio to optimize waterfowl use and avian species richness. [ABSTRACT FROM AUTHOR]

Wetland habitats continue to be lost at a unsettling rate, especially freshwater emergent wetlands that are isolated geographically. These are the predominant wetlands found in arid and semi-arid environments, where they serve as foci of regional biodiversity. This is especially true of the playa wetlands of the Southern High Plains of Texas, USA. The factors that determine and maintain biotic diversity in these wetlands are understood poorly. Consequently, this study examined the effect of island biogeographic and landscape features on the diversity of aquatic macroinvertebrates in playa wetlands. Macroinvertebrates were collected from playas three times during the spring and summer of 1994 and categorized as resident or transient taxa based on life history strategies. Diversity was estimated using taxonomic richness (richness) and Fisher's log-series alpha (α). Surrounding land-use practices influenced resident richness, whereas playa surface area affected resident and transient richness, as well as resident α. However, relationships differed among sampling dates. Regression analyses suggested that transient richness and α were influenced more by insular characteristics than by landscape features. The converse was true for resident richness and α. Therefore, both insular and landscape characteristics affected the diversity of macroinvertebrates in playa wetlands, but impacts were dependent on life-history strategy and time since inundation (i.e., sampling date). Consequently, conservation and management efforts targeting macroinvertebrates in playa wetlands will need to focus on the wetlands and characteristics of adjacent watershed features. [ABSTRACT FROM AUTHOR]

Playa wetlands provide functions critical to the existence of life on the High Plains portion of the Great Plains, including surface drainage, aquifer recharge, and wildlife habitat. These small, circular, isolated depressional wetlands with closed watersheds have a dynamic, unpredictable hydroperiod, which is essential to the maintenance of biodiversity. Most numerous in the Southern High Plains of northwestern Texas and eastern New Mexico, playas have been impacted by sedimentation, pit excavation, road construction, industrial and municipal wastewater, feedlot runoff, urban development, overgrazing, and deliberate filling. Despite being declared, as a wetland class, jurisdictional "waters of the United States" since 1977, regulations and laws for conservation of wetland functions have seldom been applied to playas. The January 2001 Supreme Court decision, Solid Waste Agency of Northern Cook County (SWANCC) v. United States Army of Corps of Engineers, likely eliminated federal regulation of impacts covered by the Clean Water Act in all but a few playas. Although still subject to the Federal "Swampbuster" provision enacted by the 1985 Food Security Act, extended natural dry periods allows for frequent cultivation and other activities in playas without incurring violation, contributing to the continued degradation of playa functions. None of the states with significant numbers of playas have regulations for the conservation of playa functions. Suggestions for the successful future conservation of playas and their associated functions include (1) increased promotion and implementation of existing federal and state conservation programs specifically for playas; (2) proposed state regulations for playa conservation; (3) recognition of agricultural impacts on wetland determinations; (4) creation of Wetland Management Districts to preserve intact, functioning playas; and (5) increased public education on the value of playas. [ABSTRACT FROM AUTHOR]

Field and laboratory data combined with geochronological information were used to investigate the nature and rates of pedogenesis of three late Holocene soils at the Lubbock Lake archaeological site (Southern High Plains of Texas). A variety of pedologic characteristics become better expressed with time, and aerosolic additions and burial of the soils significantly affect the development of these characteristics. Organic carbon accumulates rapidly in initial stages of develop- ment of the A horizon: mollic epipedons form in about 100 years and steady-state conditions of organic carbon content are attained in about 1000 years. Upon burial, organic carbon content of the A horizon quickly decreases. Calcic horizons form in 200 years and minimally developed argillic horizons form in 450 years, the result of infiltration of clay and carbonate derived from aerosolic dust. Horizonation is better expressed with time, and B-horizon hues redden from 10YR to 5YR in 3500 years. Locally, landscape position is an important factor: along the valley axis A horizons become cumulic and mixed-layer illite-smectite clays form at the expense of illite because more moisture is available and there are strong seasonal contrasts in wetting and drying. [ABSTRACT FROM AUTHOR]