Filters: Contacts: SmithLoren M. (X)
12 results (71ms)|
Filters
Date Range
Extensions Types Contacts Categories |
Playas are shallow depressional wetlands and the dominant wetland type in the non-glaciated High Plains of the United States. This region is one of the most intensively cultivated regions in the Western Hemisphere, and playas are profoundly impacted by a variety of agricultural activities. Conservation practices promoted through Farm Bills by the U.S. Department of Agriculture (USDA) that influence playas and surrounding catchments impact ecosystem functions and related services provided by wetlands in this region. As part of a national assessment, we review effects of agricultural cultivation and effectiveness of USDA conservation programs and practices on ecosystem functions and associated services of playas....
Categories: Publication;
Types: Citation
Hydrologic budgets for depressional wetlands require estimates of runoff from watersheds. In the Southern High Plains, where there is little elevation relief, ground surveys provide accurate watershed estimates but are time-consuming and costly. Estimates can be derived at lower cost from DEMs (Digital Elevation Models) and topographical maps, but data resolution and interpretation introduces errors. Other computational methods provide alternatives for estimating watershed area. Two computational methods based on longitudinal distances and elevations are described; minimal distance method and weighted minimal distance method. Twenty playas were ground surveyed to obtain baseline estimates of watershed area. Watershed...
Categories: Publication;
Types: Citation
The majority of the High Plains region is comprised of shortgrass prairie. Within this shortgrass prairie region playas are the dominant wetland type and hydrological feature. Playas are shallow depressional recharge wetlands each existing within their individual catchments. The High Plains is also one of the most intensively cultivated regions in the western hemisphere. Therefore playas are directly influenced by agricultural practices and USDA conservation programs. The primary ecosystem services provided by playas include biotic habitat flood-water storage and
Categories: Publication;
Types: Citation
More than 25,000 playa wetlands are embedded in the Southern High Plains (SHP), USA. The SHP is one of the most intensively cultivated areas in the world and, as a result, the function of playas has been altered by deposition of eroded sediments. We monitored water levels in 33 playas in summer 2003 to examine the influence of land use (cropland vs. native grassland) and playa characteristics (playa area, watershed size, starting water level, volume loss, sediment depth, percent playa vegetation cover, and soil texture zone) on water loss rate and hydroperiod (consecutive days a playa held measurable surface water). Multiple regression models (selected using Akaike’s Information Criterion) indicated that land use,...
Categories: Publication;
Types: Citation
Playa wetlands are the major habitat for amphibians in the Southern Great Plains, USA.... | Article from Copeia June 4, 2008
Categories: Publication;
Types: Citation
1. Hydroperiod, wetland size and land use of watersheds surrounding wetlands have important individual influences on plant communities in wetlands. Our objectives were to determine the effect and relative importance of local and landscape factors on plant species richness, diversity and composition of different functional groups (i.e. total, wetland-dependent, perennial, annual and exotic species) in recently inundated playa wetlands.2. We surveyed plant communities in 80 wet playas in the Southern High Plains, USA, and measured local factors: water depth, playa volume loss, sediment depth and playa area. We included landscape variables within 3 km: number of playas, edge density, percentage urban area and percentage...
Categories: Publication;
Types: Citation
Playa wetlands in the Southern High Plains provide services such as stormwater storage, groundwater recharge, and biodiversity provisioning. However, watershed erosion has negatively impacted these services. Previously, we demonstrated that water loss rate was influenced by land use variables such as watershed cultivation (tilled index) and playa volume loss (hydric soil defined wetland volume). Because non-anthropogenic water loss in playas is limited to evaporation, transpiration, and infiltration processes, our objective was to determine the impact of wetland vegetation characteristics and land use variables on water loss rate in playa wetlands. We recorded water levels of 70 playas through the summers of 2003...
Categories: Publication;
Types: Citation
Categories: Publication;
Types: Citation
Historically, playas in the Southern High Plains (SHP) were identified by the presence of hydric soils. The United States Department of Agriculture (USDA) has begun a reclassification and remapping of upland and depressional soils for the playa region of Texas. For eight counties in Texas, we compared the occurrence of playas, as indicated by soils designated as hydric in original soil surveys, to designations in remapped soil surveys. We estimate a 65% decrease in playa numbers and 50% decrease in area as defined by the presence of hydric soil. Anthropogenic impacts, resulting in an altered hydrology and masking of hydric soil are proposed as primary factors responsible for reduction in playa numbers. Other potential...
Categories: Publication;
Types: Citation
Agricultural land use surrounding wetlands can influence various aspects of amphibian ecology. Amphibians inthe Southern Great Plains of North America exhibit altered demographics and body size in playa wetlands with cultivatedwatersheds compared to those in grassland watersheds. We identified metacercariae of the trematode Clinostomumattenuatum in dominant playa amphibians and therefore examined its prevalence between postmetamorphic individualsinhabiting wetlands in grassland and cultivated landscapes. During 1999 and 2000, 5,621 Bufo cognatus, 9,565 Ambystomatigrinum mavortium, and 49,373 Spea multiplicata captured at playa wetlands were examined for C. attenuatum metacercariae.In general, metacercariae prevalence...
Categories: Publication;
Types: Citation
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...
Categories: Publication;
Types: Citation
Depressional wetlands are predominant surface hydrological features providing critical societal ecosystem services in the semiarid United States High Plains. Critical wetland properties may be threatened because this 30 million ha short-grass prairie largely was converted from grassland to cropland. Further, the United States Department of Agriculture enrolled marginal cropland into the Conservation Reserve Program (CRP). CRP reduces topsoil erosion by planting permanent cover on croplands. In the High Plains, introduced tall-grasses primarily were planted in CRP, possibly reducing precipitation runoff, an important hydroperiod driver in wetlands. We assessed land-use influence on important wetland processes (wetland...
Categories: Publication;
Types: Citation
|
