The Texas A&M Natural Resources Institute (NRI) supports private land stewardship, military land sustainability, and atrisk species conservation by providing research and policy insight to land and wildlife managers The Institute consists of experts and researchers based in 12 states in the US, situated to support the most critical natural resource challenges today This strategic plan reflects the overarching goals and priorities of the research, outreach and policy-related programs led by the Institute and its partners, articulated by the people, funding, culture and service of a Land Grant university
Rapid vertebrate speciation via isolation, bottlenecks, and drift
Speciation is often driven by selective processes like those associated with viability, mate choice, or local adaptation, and “speciation genes” have been identified in many eukaryotic lineages In contrast, neutral processes are rarely considered as the primary drivers of speciation, especially over short evolutionary timeframes Here, we describe a rapid vertebrate speciation event driven primarily by genetic drift The White Sands pupfish (Cyprinodon tularosa) is endemic to New Mexico’s Tularosa Basin where the species is currently managed as two Evolutionarily significant units (ESUs) and is of international conservation concern (Endangered)
Whole-genome resequencing data from each ESU showed remarkably high and uniform levels of differentiation across the entire genome (global FST ≈ 040) Despite inhabiting ecologically dissimilar springs and streams, our whole-genome analysis revealed no discrete islands of divergence indicative of strong selection, even when we focused on an array of candidate genes Demographic modeling of the joint allele frequency spectrum indicates the two ESUs split only ~4 to 5 kya and that both ESUs have undergone major bottlenecks within the last 25 millennia
Our results indicate the genome-wide disparities between the two ESUs are not driven by divergent selection but by neutral drift due to small population sizes, geographic isolation, and repeated bottlenecks While rapid speciation is often driven by natural or sexual selection, here we show that isolation and drift have led to speciation within a few thousand generations We discuss these evolutionary insights in light of the conservation management challenges they pose
Black, A.N., E.J. Heenkenda, S. Mathur, J.R. Willoughby, B.L. Pierce, S.J. Turner, D. Rizzuto, J.A. DeWoody. 2024. Rapid vertebrate speciation via isolation, bottlenecks, and drift. Proceedings of the National Academy of Sciences 121:e2320040121.
White sands pupfish (Cyprinodon tularosa).
Photo from National Parks Gallery
Wild Furbearer Management and Conservation in North America Chapter 2: Furbearer Management in Mexico
The cultural and biological importance of furbearing species and their management and conservation in Mexico is unique and not as well developed compared to more northern regions of North America The Republic of Mexico and the United States of America (hereafter, US) share a long and rich history regarding natural resources The shared border between these two countries has resulted in a high diversity and cultural importance of furbearing species for both countries The classic work, Wild Furbearer Management and Conservation in North America, did not include a specific and comprehensive synthesis regarding furbearer management in Mexico
Here, we attempt to contribute to the understanding of furbearers in Mexico through the following sections of this chapter We begin with providing a broad summary of the early history of the fur trade in the country from the Aztec period to the present We then provide an overview of the rich diversity of furbearing species as well as a general overview of the legal and regulatory framework, both historical and current, that has shaped the management and use of furbearing species in Mexico We conclude with the modern fur trade, both commercial and noncommercial, and contemporary concerns associated with furbearer management and conservation
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Example of importance of wildlife in spiritual rituals and other aspects of Mayan culture in Mexico Photo from Wild Furbearer Management and Conservation in North America
Authors
Roel Lopez
Raul Valdez
Carlos Gonzalez-Rebeles Islas
Eliz Regina Martinez-Lopez
Andrea Montalvo
Cite
Lopez, R. R., R. Valdez, C. González-Rebeles
Islas, E R Martínez-Lopez, and A E Montalvo 2024 Furbearer management in Mexico
Pages 21–218 in T L Hiller, R D Applegate, R D Bluett, S N Frey, E M Gese, and J F
Organ, editors Wild furbearer management and conservation in North America Wildlife Ecology Institute, Helena, Montana, USA https://doiorg/1059438/RVTM1942
Assessing ecological and socio-political factors in site selection for ocelot reintroduction in Texas
Wildlife reintroduction site selection requires the consideration of species' ecology but also socio-political factors that may impact conservation efforts These socio-political dimensions may be especially important for endangered carnivore reintroductions on private lands in the United States, where landowner support for the reintroduction is a necessity given landowner concerns about ecological and legal impacts of carnivore restoration We designed an assessment to identify potential sites for reintroduction of the federally endangered ocelot (Leopardus pardalis pardalis) in Texas, a state where over 97% of lands are privately owned
We incorporated International Union for Conservation of Nature recommendations in to a geospatial analysis evaluating potential reintroduction sites based on site size, ecological and life history requirements of ocelots, potential natural and anthropogenic threats, and the socio-political context of each site We identified the five highestranking sites that had species-specific suitable landscape structure of woody cover, fine-scale vegetative cover, minimal natural and anthropogenic threats, and that present landownership patterns that are logistically feasible for conservation planners to navigate
Our assessment provided information for ocelot conservation planning and established a framework for incorporating private land data into large-scale assessments of wildlife reintroduction sites on private lands
Authors
Cite
Martinez, L A, J V Lombardi, G Powers, A D Anderson, T Campbell, & R R Lopez 2024
Assessing ecological and socio-political factors in site selection for ocelot reintroduction in Texas Conservation Science and Practice, e13113 https:// doiorg/101111/csp213113
Ocelot (Leopardus pardalis) Photo from Adobe Stock.
Lindsay Martinez Jason Lombardi Garrett Powers
Amanda Anderson Tyler Campbell Roel Lopez
Food niche responses in southern Texas small mammal communities
Land managers interested in maintaining species diversity often face difficult decisions when managing cattle grazing Choosing a successful stocking regime and intensity for a particular region can be difficult Landowners in the southern Texas region face challenges identifying successful stocking regimes or grazing intensity because of high temperatures from April through October and frequent droughts that often last up to or longer than 3 years Cattle grazing is a major southern Texas agricultural industry that can have profound impacts that alter the diversity and structure of vegetation Small mammals are an appropriate focal group for understanding ecosystem changes because of their rapid reproductive cycles and successful use in monitoring ecosystem conditions
From 2015 to 2020, we conducted a small mammal mark–recapture study to understand the impacts of grazing, along with variability in temperature and rainfall, on small mammal abundance in southern Texas Sampling occurred within four different cattle grazing treatments to provide insight on cattle interactions with small mammals We analyzed changes in small mammal abundance between three groups based on their food preferences: omnivores, granivores, and herbivores
For all three groups, there was a negative influence of temperature, but not precipitation and year, on abundance With landscapes changing with time, land managers could use these data as a baseline for monitoring small mammal abundance in this region and potentially other similar native rangelands
Authors
Camryn Kiel
Andrea Montalvo
Cite
Leonard Brennan
Michael Morrison
Pence, AR, CM Kiel, A Montalvo, BL Pierce, LA Brennan, and ML Morrison 2024 Food Niche Responses in Southern Texas Small Mammal Communities The Southwestern Naturalist 63: 216-223
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Alexis Pence
Brian Pierce
Ord’s kangaroo rat (Dipodomys ordii). Photo from Adobe Stock
Creating a systematic prioritization of stream reaches for conservation of aquatic species
Human impacts on aquatic ecosystems have resulted in systemic declines of global freshwater species abundance and richness Conservation and governmental groups worldwide have designated protected areas to preserve the remaining diversity The biodiversity hotspot approach, which designates areas based on high levels of species richness, has been useful for identifying areas to protect both terrestrial and aquatic species However, for freshwater species, additional approaches are warranted to identify specific stream reaches for protection and/or restoration
To address this issue, we present a methodology to create a Gridded River Identification System (GRIS) for river segments based on 30 arc-second grids (~09km) using the USGS National Hydrography High Resolution Dataset To demonstrate the utility of this approach, we obtained occurrence data for six imperiled freshwater mussel species in Texas and created ensemble species distribution models (ESDMs) based on climate and topographical variables Predicted occupancies were overlayed onto the GRIS in Texas The predicted occupancies were rank ordered from 1 to 5, with 1 being the lowest probability of occupancy and 5 being the greatest The rank-ordered segments were then used to identify reaches for conservation and restoration activities
Our approach is novel and widely applicable to other freshwater species so long as distribution information is available The GRIS can also be easily developed for stream systems outside of the current study area Future studies could build upon our framework by incorporating additional taxa data and projected changes in climate and land use
Authors
Alexander Kiser
Cody Craig
Timothy Bonner
Brad Littrell
Chase Smith
Clinton Robertson
Cite
Hsiao-Hsuan Wang
William Grant
Matthew Johnson
Roel Lopez
Charles Randklev
Kiser, AH, CA Craig, TH Bonner, B Littrell, CH Smith, CR Robertson, H Wang, WE Grant, MS Johnson, R Lopez, and CR Randklev 2024 Creating a systematic prioritization of stream reaches for conservation of aquatic species Ecosphere 15:e4772.
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Effects of large-scale gold mining on habitat use and selection by American pronghorn
Anthropogenic disturbances, including extraction of natural resources and development of alternative energy, are reducing and fragmenting habitat for wildlife across the globe Effects of those disturbances have been explored by studying populations that migrate through oil and gas fields or alternative energy facilities
Extraction of minerals, including precious metals and lithium, is increasing rapidly in remote areas, which results in dramatically altered landscapes in areas of resident populations of wildlife
Our goal was to examine how a resident population of American pronghorn (Antilocapra americana) in the Great Basin ecosystem selected resources near a largescale disturbance year around We investigated how individuals selected resources around a large, open-pit gold mine We classified levels of disturbance associated with the mine, and used a random forest model to select ecological covariates associated with habitat selection by pronghorn We used resource selection functions to examine how disturbances affected habitat selection by pronghorn both annually and seasonally Pronghorn strongly avoided areas of high disturbance, which included open pits, heap leach fields, rock disposal areas, and a tram
Pronghorn selected areas near roads, although selection was strongest about 2km away We observed relatively broad variation among individuals in selection of resources, and how they responded to the mine The Great Basin is a mineral-rich area that continues to be exploited for natural resources, especially minerals
Sagebrush-dependent species, including pronghorn, that rely on this critical habitat were directly affected by that transformation of the landscape, which is likely to increase with expansion of the mine As extraction of minerals from remote landscapes around the world continues to fragment habitats for wildlife, increasing our understanding of impacts of those changes on behaviors of wildlife before populations decline, may assist in the mitigation and minimization of negative impacts on mineral-rich landscapes and on wildlife populations
Authors
Megan Osterhout
Kelley Stewart
Brian Wakeling
Cody Schroeder
Cite
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Marcus Blum
Julia Brockman
Kevin Shoemaker
Osterhout, M.J., K.M. Stewart, B.F. Wakeling, C.A. Schroeder, M.E. Blum, J.C. Brockman, and K.T. Shoemaker. 2024. Effects of large-scale gold mining on habitat use and selection by American pronghorn. Science of the Total Environment, https://doi.org/10.1016/j.scitotenv.2024.170750.
Thermal tolerance exceedances of an endangered unionid mussel in the Rio Grande Basin, with implications for river management
Freshwater mussels are globally imperilled, which is attributed to their sensitivity to changes in streamflow and temperature The Black River in south-eastern New Mexico, USA, harbours a stronghold population of the federally endangered unionid Popenaias popeii (Texas hornshell) Decreasing discharge and elevated water temperatures are considered the primary factors responsible for the species’ decline However, the impact of these factors has not been quantified directly, which may hinder conservation efforts
The upper thermal tolerances (LT05 and LT50) of Black River P popeii larvae (glochidia) and newly transformed juveniles were evaluated Individuals were acclimated to 27°C and then immersed at five experimental temperatures (28, 30, 32, 34 and 36°C) for 24 h (glochidia) or 96 h (juveniles) The thermal tolerances of P popeii and its presumed host fishes were then overlain onto in situ water temperature and discharge data to determine thermal exceedances in the past 15 years Temperature was hindcast back to 2007 using machine learning (random forest model) and coupled with discharge
For glochidia, LT05 was exceeded frequently (41%) and LT50 was exceeded occasionally (13%) during spring and summer periods, whereas juvenile thresholds were never exceeded Upper continuous duration above threshold (UCAT) analysis revealed periods of catastrophic high temperature, which were used to determine discharge bottlenecks
This study demonstrates how laboratoryderived physiological thresholds can be used in conjunction with environmental data to evaluate the hydrological needs of aquatic organisms, which is useful in efforts to maintain flow regimes that protect native ecosystems
Authors
Xenia Rangaswami
Alexander Kiser
Matthew Ramey
James Stoeckel
Cite
David Berg
Roel Lopez
Charles Randklev
Rangaswami, XL, AH Kiser, M Ramey, JA
Stoeckel, DJ Berg, RR Lopez, CR Randklev 2023 Thermal tolerance exceedances of an endangered unionid mussel in the Rio Grande Basin, with implications for river management Aquatic Conservation: Marine and Freshwater Ecosystems 33, 1431-1444
Rio Grande River Photo from Adobe Stock
Coyotes eat flies at carrion
Coyote (Canis latrans) are a generalist carnivore that are presumed to be a facultative scavenger. However, we observed feeding behavior that calls into question the simplicity of this interaction. During a carcass deployment experiment, we recorded 105 potential coyote feeding observations, of which 44 included information regarding the food item being consumed. Adult necrophagous flies accounted for these detailed observations as often as carrion (21% of all potential feeding events). Most observations of necrophagous fly consumption occurred at a single block during a restricted window of time, which could reveal individual variation in coyote diet.
Our finding highlights the importance of characterizing indirect food web interactions at carcasses. In our case, coyotes likely encountered necrophagous flies in the process of scavenging at carcasses. Food webs may thus include dependencies (e.g., necrophagous flies reproducing on decomposing organic matter) that can generate spatiotemporally limited interactions involving facultative consumers. Moving forward, researchers can advance knowledge regarding food webs by defining the complete suite of consumer interactions at resource pulses.
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David Mason
Abby Jones
Brandon Barton Authors
Mike Proctor
Stephen Webb
Marcus Lashley
Mason, DS, AK Jones, BT Barton, MD Proctor, SL Webb, and MA Lashley 2023 Coyotes eat flies at carrion Food Webs 37:e00309
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Coyote (Canis latrans)
Camera-trap basking arrays detect western chicken turtles in dynamic ephemeral wetland mosaics
Landscapes dominated by ephemeral wetlands vary in both space and time as temperature and precipitation vary regionally, seasonally, and annually. Regionally, the size, density, and spatial configuration of ephemeral wetland complexes are determined by where rain falls and is diverted, creating large wetland complexes following flood events or smaller complexes following wandering seasonal storms. Locally, individual ephemeral wetlands exhibit an array of sizes and shapes and vary in permanence with temperature and precipitation, creating drying gradients across the landscape among wetlands, but also within them, from highly ephemeral edges to more permanent wetland centers. For species dependent on ephemeral wetland complexes, these spatial and temporal dynamics continually alter the location, size, density, and spatial configuration of suitable habitat. For biologists studying species dependent on ephemeral wetland complexes, these spatial and temporal dynamics continually alter the location, number, type, density, and spatial configuration of sites needed to sample suitable habitat for the target species, which can be unmanageable to track when sampling methods involve intensive trapping.
Semiaquatic freshwater turtles, in particular, often inhabit ephemeral wetland complexes and can be difficult to study, because individuals frequently make far-ranging terrestrial movements among many wetlands for mating, foraging, basking, aestivating, and overwintering purposes. These ecological attributes make semiaquatic freshwater turtles vulnerable at multiple scales, from individual road mortality to large-scale habitat loss, consequently resulting in the need for
population monitoring at multiple scales for management, conservation, or restoration goals. Population monitoring of semiaquatic freshwater turtles traditionally involves invasive trapping with baited or unbaited hoop nets, deployment of basking traps, or less invasive visual encounter surveys using spotting scopes and binoculars. Sampling turtles across large, dynamic, ephemeral wetland complexes with these traditional monitoring methods can be time-consuming and expensive, but camera traps have recently become a cheap, efficient, non-invasive, automated alternative to studying turtle movements and basking, nesting and aestivation, and detection/survival. Herein, we assess the efficacy of a relatively inexpensive camera-trap basking array designed to move up and down with the changing water levels of ephemeral wetlands occupied by Western Chicken Turtles (Deirochelys reticularia miaria), a subspecies under review for protection under the U.S. Endangered Species Act.
Brandon Bowers
Corey Fielder
Danielle Walkup
Roel Lopez Authors
Cite
Wade Ryberg
Toby Hibbitts
Mickey Parker
Paul Crump
Bowers, B.C., C.M. Fielder, D.K. Walkup, R.R. Lopez, W.A. Ryberg, T.J. Hibbitts, M.R. Parker, and P.S. Crump. 2023. Camera-trap Basking Arrays Detect Western Chicken Turtles (Deirochelys reticularia miaria) in Dynamic Ephemeral Wetland Mosaics. Herpetological Review 54, 368-372
Comparing contemporary models to traditional indices to estimate abundance of desert bighorn sheep
Aerial surveys for large ungulates produce count data that often underrepresent the number of animals. Errors in count data can lead to erroneous estimates of abundance if they are not addressed. Our objective was to address imperfect detection probability by developing a framework that produces realistic and defensible estimates of bighorn sheep (Ovis canadensis) abundance.
We applied our framework to a population of desert bighorn sheep (O. c. nelsoni) in the Great Basin, Nevada, USA. We captured and marked 24 desert bighorn sheep with global positioning system (GPS)-collars and then conducted helicopter surveys naïve to the locations of collared animals. We developed a Bayesian integrated data model to leverage information from telemetry data, helicopter survey counts, and habitat characteristics to estimate abundance while accounting for availability and perception probability (i.e., detection given availability). Distance to ridgeline, terrain ruggedness, tree cover, and slope influenced perception probability of sheep given they were viewable from the helicopter. There was also annual variation in perception probability (2018: median=0.64, credible interval [CrI]=0.37–0.87; 2019: median =0.81, CrI=0.49–0.97). The abundance estimates from the integrated data model decreased from 2018 (594; 95% CrI=537–656) to 2019 (487; 95% CrI=436–551). In addition, accounting for availability and imperfect perception resulted in greater estimates of abundance compared to traditional directed search methods, which were 340 for 2018 and 320 for 2019 Our modeling framework can be used to generate more defensible population estimates of bighorn sheep and other large mammals that have been surveyed in a similar manner
Authors
Marcus Blum
Frances Buderman Joe Bennett
Cite
Kelley Stewart Mike Cox Perry Williams
Blum, M.E., F.E. Buderman, J.R. Bennett, K.M. Stewart, M. Cox, and P.J. Williams. 2023. Comparing contemporary models to traditional indices to estimate abundance of desert bighorn sheep The Journal of Wildlife Management, e22517
Desert bighorn sheep (Ovis canadensis)
Spatial ecology of the Texas alligator lizard in Blanco County, Texas
Texas Alligator Lizards (Gerrhonotus infernalis) range from Central Texas into adjacent northeastern Mexico, and published ecological studies on their terrestrial and arboreal movement patterns are lacking. We used radiotelemetry to assess movements, annual home range, and arboreal activity of G. infernalis at Bamberger Ranch Preserve, Blanco County, Texas, to provide baseline ecological data for populations occurring in the northernmost extent of the species’ range.
Movement patterns were influenced by temporal (e.g., seasonal) and behavioral cues (e.g., breeding period), but generally no differences were observed between sexes. Annual home range varied, but males averaged larger 95% MCP (minimum convex polygon) annual home ranges, while females averaged larger 50% MCP core use areas, although we were unable to test for differences due to low sample sizes. Males and females exhibited similar arboreal trends, but arboreal activity did vary by season and diurnal period. Most arboreal activity occurred during the summer and late spring, with less during the fall and winter months. Gerrhonotus infernalis, on average, inhabited higher perch sites during the evening and morning diurnal periods and lower perch sites during the afternoon periods.
These findings provide novel insights into the ecology of G. infernalis in Central Texas and will aid in future management activities.
Authors
Wade Ryberg
Danielle Walkup
Jared Holmes
Toby Hibbitts
Fielder, CM, WA Ryberg, DK Walkup, JM Holmes, and TJ Hibbitts 2023 Spatial ecology of the Texas Alligator Lizard (Gerrhonotus infernalis) in Blanco County, Texas Western North American Naturalist 83, 315-324
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Corey Fielder
Texas alligator lizard (Gerrhonotus infernalis)
Photo by Matthew Lee High
An efficient acoustic classifier for high-priority avian species in the southern Great Plains using convolutional neural networks
Passive acoustic monitoring is a valuable ecological and conservation tool that allows researchers to collect data from vocal species across large geographic areas and temporal spans. Grassland bird populations, many of which are indicators of ecosystem health, have experienced precipitous declines over the past several decades. Acoustic monitoring of grassland bird populations provides opportunities to monitor declines and focus conservation practices, yet the ability to identify species efficiently and accurately from acoustic data is challenging. Therefore, development of automated classifiers such as convolutional neural networks (CNNs) are at the forefront of streamlining detection and identification of individual species.
Here, we present a CNN classifier for 5 key grassland bird species across southcentral Oklahoma, a part of the southern Great Plains: northern bobwhite (Colinus virginianus), painted bunting (Passerina ciris), dickcissel (Spiza americana), eastern meadowlark (Sturnella magna), and Bell's vireo (Vireo bellii). We compiled a high-quality training dataset consisting of 6,933 calls, built semiautonomously using template matching that can be expanded easily to any bird species of interest. Our trained multilabel CNN achieved a high level of classification accuracy (≥98%) for the 5 species using the library of test calls and field recordings played using a programmable game caller. The ability to conduct acoustic wildlife surveys across large spatial extents will allow for more efficient monitoring of wildlife to determine key population parameters and trends and effects of biotic and abiotic factors (eg, vegetation, disturbance, weather) on these key species
Authors
Brandon Wolfe
Mike Proctor
Victoria Nolan
Stephen Webb
Cite
Wolfe, B, MD Proctor, V Nolan, and S.L. Webb. 2023. An efficient acoustic classifier for high-priority avian species in the southern Great Plains using convolutional neural networks. Wildlife Society Bulletin 47:e1492.
Eastern meadowlark (Sturnella magna).
Photo from Adobe Stock
Automated walk-over-weigh system to track daily body mass and growth in grazing steers
Body weight is a critical component for monitoring animal body mass, body condition, nutritional status, and health. However, traditional methods of collecting body weight are stressful, costly, and logistically impractical with cattle on extensive landscapes. Remote systems capable of collecting individual animal body weight provide a potential solution, but automatic systems may collect spurious weight measurements The objectives of this study were to (1) describe the utility of using a remote weight capture system, (2) develop methods for identifying and removing spurious measurements, and (3) cross-validate automatically collected weights with static chute collected weights
Beef steers (n = 10) were tagged with electronic Radio Frequency Identification tags and grazed for 286 days in an improved pasture (±1154 ha) containing Bermuda (Cynodon dactylon) and Tall Fescue (Festuca arundinacea) and interseeded with Annual Ryegrass (Secale cereale). A walk-over-weigh (WOW) system was designed from a platform scale connected to a TruTest® scale head and paired with a computer to save data files. In total, 5,466 raw weights associated with individuals were collected (0 kg < weight < 1,000 kg).
We assessed the use of whole herd and individual means ± 1 standard deviation calculated either daily or over the entire trial to identify potential outliers Additionally, 3 data smoothing methods were tested: a linear quadratic model, cubic splines, and polynomial regression Each method was evaluated for total weight events recorded, event frequency, measured body mass and average daily gain
Further, accuracy and precision were calculated using cross-validation with paired chute weights (n = 8) Whole herd means ± 1 SD identified the fewest spurious data points and showed a stronger relationship with paired chute weights (R2 = 090) whereas individual daily means ± 1 SD identified the most and exhibited a weaker relationship (R2 = 068) Repeated quadratic regression models provided the best results, identifying 3,759 clean weight points and providing an R2 = 096 between paired chute and WOW measurements A real-time simulation analysis found that both individual and the herd means ± 1 SD performed similarly with an average of 30% of data classified as spurious and removed from the analysis, resulting in agreement (R2 = 0.93 for both individual and herd means) between chute and WOW weight measurements. These results indicate the utility of using a simple WOW system to collect data for measuring individual animal body mass and associated metrics, which has implications on making management and marketing decisions in near real-time
Authors
Ira Parsons
Durham Norman
Brandi Karisch
Stephen Webb
Amanda Stone
Mike Proctor
Garrett Street
Parsons, I.L., D.A. Norman, B.B. Karisch, S.L. Webb, A.E. Stone, M.D. Proctor, and G.M. Street. 2023. Automated walk-over-weigh system to track daily body mass and growth in grazing steers. Computers and Electronics in Agriculture 212:108113.
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New distributional records for amphibians in Panola County, Texas
Panola County, Texas, USA, is underrepresented in terms of amphibian surveys; specifically, there has been no amphibian records published for this county in the last decade. Here, I report on six county records observed while surveying a private ranch near Elysian Field, Texas, during the spring of 2023. All specimen vouchers were deposited in the Biodiversity Research and Teaching Collections, Texas A&M University (TCWC). The anuran recording vouchers were also deposited at TCWC and given a photo voucher number (TCWC-PV). All specimens were collected by CMF, all identifications were verified by Toby J. Hibbitts, and both common and scientific names follow Crother (2017). Specimens were collected under a Texas Parks and Wildlife Department permit issued to Toby J. Hibbitts (SPR-0506-662).
Authors
Fielder, C.M. 2023. New Distributional records for Amphibians in Panola County, Texas, USA. Herpetological Review 54(3): 410. Cite
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Corey Fielder
Cajun chorus frog (Pseudacris fouquettei)
Photo by Jeromi Hefner
The effectiveness of an unmanned aerial vehicle in controlled fecal pellet surveys
The declining costs and increasing capabilities of unmanned aerial vehicles (UAVs) have led to their expanded use in natural resources research and management. Generally, UAV-based data collection involves larger (i.e., more visible) components (e.g., large mammals, blocks of forest) that are more easily observed by UAV cameras. Little research has focused on UAV effectiveness in researching and monitoring relatively small and less visible objects. Fecal surveys are broadly applied methods for determining wildlife occupancy, population abundance and trends, and land use. Potentially, UAVs could improve, or augment, fecal surveys by reducing time and effort expenditures, expense, and impacts on focal species behavior. Yet, their effectiveness and ability to produce accurate and precise estimates have not yet been evaluated. We compared UAV surveys at multiple observation altitudes to traditional in-person on-the-ground surveys to test relative UAV effectiveness.
We created artificial survey plots with a randomly assigned number of cereal pellets that mimicked the morphology of rabbit pellets. UAVs provided similar data to inperson counts for presence-absence inference. Additionally, raw counts were similar in pattern to in-person observations for pellets across a range of cover classes but were biased low in most circumstances. Heavy cover negatively affected both methods but resulted in higher undercounting with the UAV. The density of vegetation cover impacts pellet detection for both in-person and UAVbased surveys.
Our research demonstrates that UAV-based fecal surveys are viable strategies. Further research in different conditions and fecal shapes is required for full implementation.
Authors
Aaron Facka
Andrea Montalvo
Cite Israel Parker
Ian Gates
Brian Pierce
Roel Lopez
Parker, ID, AN Facka, AE Montalvo, IT
Gates, BL Pierce, and RR Lopez 2023
The effectiveness of an unmanned aerial vehicle in controlled fecal pellet surveys Western Wildlife 10:25-33
Unmanned aerial vehicle (UAE)
Lessons learned from a conservation translocation of a microendemic habitat specialist
Translocations are often characterized as “successes” or “failures” However, this dichotomy masks the challenges of successful translocations and ignores important lessons learned in cases where a population was not established in perpetuity We translocated 76 individuals of an imperiled endemic lizard, the Dunes Sagebrush Lizard (Sceloporus arenicolus), to a locality where it had gone extinct Translocated lizards survived and reproduced in small numbers Based on intensive monitoring, we were able to conclude the incipient population declined to zero individuals after 4years It is possible that predation, Allee effects, or stochastic factors prevented the population from sustaining itself at this historically occupied site
Valuable lessons for conservation translocations can be taken from this case We offer novel perspectives on the IUCN Guidelines for Reintroductions and Other Conservation Translocations regarding release site selection, propagule bias, behavioral monitoring, population monitoring, and issues of land tenure We recommend pairing knowledge of habitat requirements with quantitative analyses to select suitable release sites, translocating gravid females to jump-start population growth, coupling delayed releases with intensive behavioral monitoring, using Poisson-based models to determine necessary intensity of monitoring, and recognizing how issues of land tenure may present pitfalls for conservation translocations in the long term.
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Authors
Mickey Parker
Toby Hibbitts
Wade Ryberg
Lee FItzgerald
Parker, MR, TJ Hibbitts, WA Ryberg, and LA Fitzgerald 2023 Lessons learned from a conservation translocation of a microendemic habitat specialist Restoration Ecology, e13981.
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Dunes sagebrush lizard (Sceloporus arenicolus) Photo by Lee Fitzgerald
Feasibility and application of using Texas horned lizard scat to predict lizard size and age class
Texas horned lizards (Phrynosoma cornutum; hereafter THL) were once abundant throughout Texas; however, their distribution and abundance have decreased, and currently they are listed as a threatened species in the state Detection of THL can be difficult because of their cryptic nature and sporadic distribution Using indirect signs such as fecal pellets (ie, scat) to determine occupancy is a widely practiced survey technique. However, it is unknown if scat size can be used to determine the age structure of THL.
Our objectives were to determine 1) if THL scats were consistently produced and at consistent size in relation to lizard snout‐vent length (SVL), 2) if THL scats remain intact in the environment, and 3) if scat length and diameter could be used as an indicator of THL size, which could be used to determine population age structure We tested the feasibility of using scat morphometrics to estimate age class ratios, body size, and population estimates for THL
Data collection was conducted in 3 phases, which occurred from 2001–2019 Scats were collected daily for 6 days from 6 hatchling, 10 juvenile, and 10 adult THL collected from southern Texas Texas horned lizards were measured for snout‐to‐vent length (mm) and categorized as either hatchling, juvenile, or adults based on estimates from the literature. On average, THL produced one scat/day, typically in the morning. Scat length and width increased as lizard size (i.e., SVL) increased with each age class. Scat size of each age class of THL was consistent between days; thus, objective one was met. Scats were measured for length and width (mm) and placed in direct sunlight for 90 days, submerged in water for 2 days, and placed in typical summer weather conditions of southern Texas
Texas horned lizard scat did not shrink or swell in size or decay due to environmental conditions during the 90‐day experiment Thus, THL scats do remain intact in the environment We collected scat from 70 known‐size THL from south‐central Texas Simple log‐log regression models demonstrated a linear relationship (r² = 089) between loge (SVL) and loge (scat length, mm) Slopes were similar among age classes, but intercepts differed as expected. We tagged individual THL to follow growth rates through time. Thirteen of 20 tagged females produced 178 hatchlings, of which 56, 23, 19, and 6 were recaptured during their hatchling, 2nd, 3rd, and 4th year, respectively. Models for growth rates of known‐age THL were not equal (ηˆ² ₚ = 0.73,F₆,₆₉ = 446, P < 00001) among age classes Growth rates were faster in year 1 (0101 ± 0003 mm d ¹) and year 2 (0099 ± 0007 mm day ¹) and slowed (0076 ± 0009 mm day ¹) during their 3rd year Scat from THL reliably can be used to estimate population age class structure, body size, and population estimates However, our growth rate analyses suggest that THL appear to experience slower growth rates than during previous decades, and thus, THL require reevaluation as to what SVL size constitutes an adult THL
Huerta, JO, SL Webb, SE Henke, DB Wester, F Hernandez, and RL Powell 2023 Feasibility and application of using Texas horned lizard scat to predict lizard size and age class Wildlife Society Bulletin 47:e1446
Cite
Javier Huerta
Scott Henke
David Wester
Cord Eversole
Stephen Webb
Fidel Hernandez
Distribution and demography of the alligator snapping turtle in Texas: A 20-year perspective
Texas contains the southwestern range edge of Macrochelys temminckii (Alligator Snapping Turtle), but there is relatively little published information on this species within the state To document its range and assess temporal changes in its distribution and demography, we sampled 23 sites from 1999 to 2001 We then resurveyed 22 of these sites and sampled 29 additional sites in 2020–2021 Detection outcomes were consistent between 18 of the 22 resurveyed sites Sex ratios and body-size distributions were similar across surveys Catch per unit effort (CPUE) was lower in areas with trotlines, corroborating known interactions between turtles and fishing gear. Patterns in CPUE indicate Gulf of Mexico-draining watersheds are important systems for the species, while CPUE was lower in Mississippi-draining watersheds.
Authors
David Rosenbau
D. Craig Rudolph
Daniel Saenz
Lee Fitzgerald
Ryan Nelson
Cite
Christopher Collins
Toby Hibbitts
Ricky Maxey
Paul Crump
Christopher Schalk
Rosenbaum, D., D.C. Rudolph, D. Saenz, L.A. Fitzgerald, R.E. Nelson, C.S. Collins, T.J. Hibbitts, R.W. Maxey, P. Crump, and C.M. Schalk. 2023. Distribution and Demography of the Alligator Snapping Turtle (Macrochelys temminckii) in Texas: A 20-Year Perspective. Southeastern Naturalist 22:197-220
Native grasslands i arrival of the first s loss, degradation b significantly impac and has left consid the degradation of species has becom restoring areas to n restoration activitie biodiversity, soil he addition, there are restoration of degr
Texan by Nature, in this project to qua restoring rangelan play Texas A&M Na University Rangela Department (RWF collection and data EcoMetrics This re results of this case other operators in
Authors
Jacob Lampm
Kypfer Cordt
Forrest Cobb
Go to source
William Fox
Doug Tolleson
Edward Osei
Roel Lopez
Mycha Van Allen
ECONOMICVALUESOF WHITE-TAILEDDEERINTEXAS:PARTII
Authors
Shraddha Hegde
Alison Lund
Jacob Dykes
Tammi Johnson
Angelica Lopez
Roel Lopez
Kevin Skow
The direct spending made by white-tailed deer (Odocoileus virginianus; WTD) hunters and landowners generates economic contributions that cause a ripple effect, reaching beyond local economies The primary goal of this report was to determine an annual measure of economic activity generated by WTD hunting in Texas Using direct spending reported by stakeholder groups in our 2022 survey, we estimated the indirect and induced economic contributions and defined five types of economic activity for each: 1) number of jobs, 2) labor income, 3) value added, 4) tax revenues and 5) total economic output Understanding the size of economic contribution WTD hunting plays in Texas is an important step in better defining management and policies that protect ecological and economic benefits garnered from this important resource
This report is part of a series evaluating the economic values of whitetailed deer from surveyed hunters and landowners. Read Part I here. Go to source
DISEASECONCERNS ASSOCIATEDWITHFERALPIGS
Negative impacts associated with feral pigs (Sus scrofa) extend to agricultural production, water quality, habitat, native species, the human-wildland interface and beyond Their populations continue to expand across North America, and occur today on every continent except Antarctica Further, they transmit diseases to livestock, native and exotic wildlife species, companion animals and even humans Feral pigs harbor at least 65 bacterial, viral or parasitic infectious agents, and threaten agricultural production, agricultural supply chains, and public health In this publication, we address disease concerns endemic to feral populations and domestic pig herds throughout North America and abroad We also provide management implications and safety precautions that can be enacted to help minimize the risk of disease transmission when handling and processing feral pigs or using outdoor areas where feral pigs may be present
Josh Helcel
James Long
James Cathey
Authors
HABITATSUITABILITYMODELING FORTHEHOUSTONTOAD
Authors
Brandon Bowers
Danielle Walkup
Toby Hibbitts
Paul Crump
Michelle Lawing
Wade Ryberg
Our objectives were to update the Buzo (2008) habitat suitability model for the Houston Toad (Anaxyrus houstonensis) with current spatial data and habitat variables, quantify suitable habitat amount, develop a Species Distribution Model (SDM) to better understand environmental variable importance, and conduct connectivity modeling to prioritize areas for conservation and recovery actions. For the updated Buzo habitat suitability model, we constructed scripts to generate models that incorporate tree canopy cover, soils, and geology at varying weights and initially evaluated it with models for Bastrop County We used four different model setups designed to estimate occurrence, in order of most restrictive to least restrictive: (1) Occurrence-informed Presence Prediction Models, (2) Evenly Weighted Presence Prediction Models, (3) Integrated Substrate Presence Prediction Models, and (4) Restoration and Reintroduction Potential Prediction Models We then ran the four models for each of the remaining 12 counties and mapped the resulting outputs and quantified the suitable habitat amounts
We also constructed five ensemble species distribution models using different subsets of the Houston Toad occurrence data. We found that all five ensemble models generally identified consistent core areas for the Houston Toad, with variation among models occurring outside of those core areas. We found the proportion of deep sand (60-100 cm) in soil samples to be the most important variable in every model, generally having at least 6x the variable importance of the next most important variable While the core areas contain generally acknowledged Houston Toad presence areas, there were some additional sites that stood out as having a higher predicted probability of presence (> 05) despite having no known occurrences in these areas These areas include southern Bastrop County (south of the Colorado River) and areas north of known occurrences in Robertson and Leon counties One important conclusion from our species distribution modeling results is that the variables included in the Buzo model (ie, soil and forest cover) were also the most important variables in the species distribution models (in addition total March precipitation), despite the inclusion of other climate, vegetation, and elevation variables This suggests the Buzo model is truly capturing the key elements of the Houston Toad’s habitat
Finally, connectivity analysis showed little habitat connectivity among several or two core areas for threshold probability of presence values greater than 05 or 075, respectively The isolation of these core areas suggests that population connectivity among them will have to be achieved through the captive breeding process for this species.
Photo from Chase Fountain, TPWD
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