The Texas Parks & Wildlife Department is a Texas state agency that oversees and protects wildlife and their habitats. In addition, the agency is responsible for managing the state's parks and historical areas. Its mission is to manage and conserve the natural and cultural resources of Texas and to provide hunting, fishing and outdoor recreation opportunities for the use and enjoyment of present and future generations.The agency maintains its headquarters at 4200 Smith School Road in Austin. Wikipedia.
Hutchins B.,Texas Parks and Wildlife Department
Southwestern Naturalist | Year: 2016
We report the occurrence of the terrestrial isopod Miktoniscus medcofi from a fen in Real County, Texas, representing a new state record for the species as well as a western range extension for the genus. Morphologic characteristics closely conform to the species description and distinguish the Texas population from congeners. Miktoniscus medcofi ranges from New York to Texas and south to Veracruz, Mexico, but may represent multiple cryptic species or a species complex.
Gluesenkamp A.G.,Texas Parks and Wildlife Department
Journal of Zoology | Year: 2013
Shrinkage in body length, followed by growth, has rarely been documented in vertebrates and has been associated with stressful energetic and environmental conditions. Here, we document reversible shrinkage in an amphibian for the first time. Jollyville Plateau salamanders Eurycea tonkawae are neotenic (attain maturity while retaining an aquatic larval form) and inhabit springs and caves of a dissected aquifer in Travis County, TX, USA. We conducted mark-recapture surveys on a spring-dwelling population before and after an exceptional drought in 2008. Use of unique marks and digital photographs of individuals provided precise information on salamander growth rates during and after a period in which salamanders retreated to underground refugia to avoid desiccation during the drought. Tail width decreased significantly during the drought indicating a reduction in energy stores, a consequence of stressful environmental conditions. Unexpectedly, body length shrinkage also occurred during the drought and was followed by positive growth when spring flow resumed. Body length shrinkage could be an adaptation to coping with long periods of low food availability although its long-term effects are unknown. Given the influence of body size on many ecological and physiological characteristics of organisms, plasticity in body size may have important consequences that go undetected by researchers if shrinkage is ignored. © 2012 The Zoological Society of London.
Shen Y.,Texas Parks and Wildlife Department |
Diplas P.,Virginia Polytechnic Institute and State University
Journal of Hydraulic Engineering | Year: 2010
Reservoir releases associated with energy production and flood mitigation need to be reconciled with efforts to maintain healthy ecosystems in regulated rivers. Unsteady flow phenomena caused by hydropeaking operations typically affect riverbed erosion and fish displacement. A three-dimensional hydrodynamic model is used to simulate the flow characteristics during the passage of the rising limb of an observed hydropeaking event in a gravel-bed reach of Smith River, Virginia. The calculated time-dependent water surface elevations, velocities, and shear stresses are compared with field measurements. Further, comparison based on numerical simulations of this historical and a hypothetical "staggering" hydropeaking event reveals that the latter has the capability of reducing the area subject to erosion and prolonging refugia availability for juvenile brown trout. Issues related to the adoption of either a truly dynamic modeling approach or a quasi-steady methodology for simulating unsteady flows are examined through a proposed unsteadiness flow parameter. The insights obtained from this study can assist in properly accounting for the impact of hydropeaking operations on fish habitat and instream flow management. © 2010 ASCE.
Simpfendorfer C.A.,Center for Shark Research |
Wiley T.R.,Center for Shark Research |
Wiley T.R.,Texas Parks and Wildlife Department |
Yeiser B.G.,Center for Shark Research
Biological Conservation | Year: 2010
Understanding the movement and habitat use patterns of threatened species is essential to effective conservation planning. Modern tracking techniques such as active tracking and passive acoustic monitoring can be useful tools in elucidating this information for aquatic species. To aid in the development of conservation strategies for juvenile critically endangered smalltooth sawfish (Pristis pectinata) their fine scale movements and habitat use in southwest Florida were studied using a combination of these techniques. Between 2002 and 2006 a total of 12 individuals were actively tracked for periods of up to 24. h to provide detailed habitat use and movement parameters (distance moved, speed, and linearity). Smaller individuals (<100. cm stretched total length (STL)) had the smallest home ranges, low linearity of movement and had a preference for very shallow mud banks. Juveniles >100. cm STL demonstrated larger home ranges, preference for shallow mud or and sand banks, and remained close to mangrove shorelines. Tide was found to be the main factor influencing movement on short time scales. Sawfish <150. cm STL spend the majority of their time in water <50. cm, while larger juveniles spend most of their time in water 50-100. cm deep. From 2003 to 2007 a total of 22 individuals were fitted with acoustic tags for long-term monitoring. Juveniles >130. cm had high levels of site fidelity for specific nursery areas for periods up to almost 3. months, but the smaller juveniles had relatively short site fidelity to specific locations. The use of a combination of tracking and monitoring techniques provided an expanded range of information by generating both short and long term data on habitat use. The data demonstrated that the conservation of shallow mud and sand banks, and mangrove shorelines will benefit the recovery of these endangered elasmobranchs. © 2010 Elsevier Ltd.
Hall S.A.,Red Rock Geological Enterprises |
Boutton T.W.,Texas A&M University |
Lintz C.R.,Texas Parks and Wildlife Department
Holocene | Year: 2012
A late-Holocene alluvial sequence in north-central Texas has a 1 m thick buried cumulic soil with an A-C profile called the West Fork paleosol. It formed 2300 to 1000 yr BP and is a local equivalent of the Copan paleosol that is present throughout the southern US Great Plains. Stable carbon isotopes indicate that the paleosol and underlying gray clay formed under vegetation dominated by C 4 species (mean δ 13C: -18.3 ± 0.3‰). Diverse paleoenvironmental studies indicate that the period of paleosol formation was cool and wet and that alluvial water-tables were high, resulting in broad wet meadows across alluvial valleys, characterized by communities of grasses. Present-day wet meadows and bottomlands with Mollisols with A-C profiles along streams in the Great Plains are dominated by C 4 tallgrass species and may serve as analogues to wet-meadow environments during the late Holocene. A shift in climate to warm-dry conditions about 1000 yr BP was accompanied by deep channel cutting, low alluvial water-tables, and colonization of abandoned floodplains by trees and other C3 species, as indicated by a change in carbon isotopes to lower values (mean δ 13C: -20.8 ± 0.5‰) and correlating with the 'Medieval Warm Period'. Other stable carbon isotope studies from late-Holocene alluvium in Texas have been mistakenly interpreted as evidence for paleoenvironmental conditions opposite to those presented in this investigation. We conclude that interpretations of stable carbon isotopes from alluvium based on broad patterns of upland C4 grasses and climate can be in error, especially in cases where wet-meadow deposits and soils are present. © The Author(s) 2011.