Billy Carr Distinguished Teaching Fellowship

2023: Dan Breecker, Jackson School of Geosciences

Texas is wet in the east and dry in the west. Aridity is one of the primary factors limiting the productivity of west Texas lands. Understanding how this gradient across Texas has responded to global climate change in the past will help forecast future aridity and therefore productivity. Previous research has shown that the stable carbon isotope compositions of modern snail shells (genus Rabdotus) vary with vegetation canopy cover. The funds were used to measure snail shell carbon isotope compositions from modern snail shells and snail shells form Archaeological collections (approx. 8000 years old).

The carbon isotope compositions relate to the types and vegetation and thereby the density of canopy cover. Accounting for changes through time in the carbon isotope compositions of atmospheric CO2, we have found that the vegetation cover in San Angelo and Austin was probably not much different from modern 8000 years ago. This points to some stability of ecosystems across Texas despite climate changes during the Holocene.

2023: Tom Devitt, Department of Integrative Biology

Students in my lab conduct research on the ecology, evolution, behavior, and natural history of organisms throughout west-central Texas and Mexico. Water in west-central Texas is a precious resource due to frequent droughts and little permanent surface water, which is increasingly becoming scarcer as the climate warms.

Thanks to a Billy Carr Fellowship, my lab has initiated genome sequencing for a pair of direct-developing frogs (genus Eleutherodactylus) distributed across an east-west aridity gradient spanning the Edwards Plateau and Chihuahuan Desert ecoregions. Using genomic scans from multiple populations, we plan to investigate differences in genes responsible for adaptations to aridity to predict future responses to climate warming. These genomic data will be used to train undergraduates in authentic research that lies at the nexus of biodiversity discovery, conservation, policy, and natural resource management.

2022: Shalene Jha, Department of Integrative Biology

Ecosystem services are the benefits provided by nature to humanity and include functions such pollination, pest-control, and carbon sequestration, among many others. These services are often mediated by biodiversity and thus are inherently multifaceted, with high potential to improve crop production and food security. For example, beneficial insects can enhance pollen deposition and reduce pests for key crops, even in the face of soil disturbance and extreme climate conditions. Despite the numerous potential benefits of insect-mediated ecosystem services, we tend to quantify and value each service in isolation, missing opportunities to understand land management practices that support co-occurring ecosystem services.

Thanks to the Billy Carr Fellowship, we have been able to advance our understanding of biodiversity and ecosystem service provision within West Texas squash and cotton agroecosystems, with a specific focus on multiple ecosystem services provided by insects. Specifically, in the past year, we have evaluated the impact of different land management practices, including variation in tillage, local grassland conservation, and conspecific crop density on beneficial insect biodiversity and subsequent pollination success and pest control. Our results reveal multiple synergies for improved ecosystem service provision via farm management. Specifically, we found that the most effective specialist parasitoids and specialist pollinators exhibited resource concentration effects (unlike their generalist counterparts), increasing their visitation rates in sites with greater conspecific planting densities and conventional tillage; however, we also found that non-crop flowering plant richness and natural habitat cover promoted specialist predator abundance and pollen deposition, respectively, indicating a critical additional role of non-crop habitat in mediating ecosystem services.

2021: Thomas Juenger, Department of Integrative Biology

The Juenger lab has a longstanding interest in local adaptation and stress tolerance in plants. A current focus is on the study of native grasses, especially in the genus Panicum and Tripogon, using genetic, genomic, and field ecological approaches. We’ve been especially interested in the genetic factors impacting drought adaptation as well as the determinants of species ranges across harsh environments. Over the past year, we’ve been developing pilot data for projects studying the resurrection plant, Tripogon spicatus. Tripogon has the remarkable ability to completely desiccate and then revive upon rewatering.

Thanks to the Billy Carr fellowship, we’ve been able to initiate field work and develop genomic resources for physiological and genetic studies of the species. These initial analyses suggest that Tripogon spicatus is diploid with a genome size of approximately 500 Mb. Moreover, genetic analyses suggest that the species is self-compatible and largely inbreeding. In the future, we will develop a new genome assembly and annotation of this interesting Texas species. These resources will help with experiments to better understand the physiological processes underlying recovery from severe dehydration.”

                           Tripogon spicatus in natural habitats at Inks Lake State Park, Texas

2019: Dr. Melissa Kemp, Department of Integrative Biology.

I use the Quaternary fossil record to study how vertebrates respond to global change. The fossil record provides unrivaled long-term spatiotemporal data on species distributions and traits like dietary breadth, morphological diversity, and genetic diversity.
We are studying Hall’s Cave, a paleontological site in Kerr County, TX where 17,000 years of biological history is preserved. As we continue describing Hall’s Cave’s paleofauna, we will not only uncover additional extirpated and extinct species, but also species that persisted there despite changing environmental conditions.

Thanks to the Billy Carr Fellowship award, the kemp lab was able to support student training in fossil identification and morphometrics to address the following questions: (1) Did past climatic or anthropogenic events cause large-scale shifts in diversity? (2) Do both extinct/extirpated species and extant species show declines in population size and phenotypic breadth, or were extinct/extirpated species the only ones to undergo such declines?

Additionally, the Billy Carr Fellowship award has allowed graduate students to generate paleogenomic and isotopic data that allow us to better understand how species abundance, genetic diversity, diet, and morphological diversity were shaped by past instances of global change and what factors trigger population decline.

2018: Dr. Daniella Rempe, Department of Geological Sciences

Quantifying the role of weathered bedrock on mediating groundwater recharge in the Davis Mountains, West Texas.

Much of West Texas is mantled with thin soils and underlain by many meters of weathered and fractured bedrock. This fractured and weathered bedrock plays a role in how precipitation is partitioned into various components of the hydrologic cycle (e.g. transpiration, evaporation, runoff, and groundwater recharge). Previous researchers have suggested that bedrock fracturing is the primary control on the magnitude and spatial pattern of groundwater recharge. In this study, we use a combination of hydrologic monitoring, geophysical surveying, and geodetic measurements to advance novel techniques for quantifying water storage dynamics in the complex weathered bedrock environment that lies between soils and the groundwater table.

Thanks to the Billy Carr Fellowship award, the Rempe laboratory was able to establish a hydrological monitoring program at the University of Texas McDonald Observatory in Fort Davis, Texas to evaluate the extent to which the weathered bedrock in the Davis Mountains of West Texas facilitates the partitioning of incoming rainfall between evapotranspiration and groundwater recharge. The fellowship funds have been used to support undergraduate and graduate student travel to the MDO field site, where samples and geophysical data were collected for analysis by undergraduate and graduate students in the Rempe lab at UT Austin.

Preliminary data collected by undergraduate and graduate students suggest the fine pores of the bedrock itself store a significant amount of water, with little storage occurring in large fractures. Samples collected during drilling have been prepared by undergraduate students, and are currently being analyzed in the Rempe lab for comparison with field-scale geophysical data. The novelty and impact of the project lie in the synthesis of datasets across scales for quantifying the water storage dynamics of weathered bedrock.

2016: Dr. Larry Gilbert and Dr. Rob Plowes, Dept. of Integrative Biology, Brackenridge Field Lab

Understanding buffelgrass invasion processes on Texas ranches

Our ongoing invasive species research program is directed toward understanding invasion processes and providing novel biological control solutions for invasive species, with an emphasis on Central, South, and West Texas. A major problem species of this region is buffelgrass (Cenchrus ciliare) which is planted as a pasture grass, but rapidly escapes into the brush where it outcompetes native vegetation, alters the arthropod communities, degrades the wildlife potential, and alters the fire regime. Our research seeks to understand how the native grass community responds to buffelgrass under different management practices, and find fungal and insect detritivores associated with differences in decomposition rates between sites. Achieving a better understanding of this major invasive species in Texas ranchlands closely matches the fellowship goal by yielding potential improvements in the productivity and sustainability of this region.

2015: Dr. Mourad Krifa, Dept. of Human Ecology, Division of Textiles and Apparel

Undergraduate Student Cotton Research Team

For over two centuries, the US cotton industry has played a role of catalyst for scientific and technological innovation. Nowhere is that more apparent than in the plains of West Texas. Texas plains cotton has gained prominence through continuous improvements in productivity and quality. The most spectacular improvements were achieved in the West Texas areas served by the Lubbock and Lamesa cotton classing offices contributing a growing portion of the U.S. crop.
The Fellowship provided a unique opportunity for students from the division of Textiles and Apparel to gain awareness of the challenges facing the cotton industry in West Texas, and of the pioneering innovations developed to address them. Support from the Fellowship was instrumental in complementing our learning and research interactions with direct exposure to the industry through a field trip to the High Plains. A group of 14 students and two faculty members traveled to Lubbock and Slaton, TX in May 2015. The group visited a cotton farm, the Lubbock Cotton Growers Co-op gin, the USDA-AMS cotton classing office, Plains Cotton Growers, Inc., and the Fiber and Biopolymer Research Institute at Texas Tech University. The farm visit was particularly eye-opening for the students. The group had the privilege of visiting Buzz Vardeman’s farm. Mr. Vardeman is no ordinary farmer, he is a pioneering inventor whose inventions have revolutionized farming in West Texas and beyond. For instance, many of the innovations that make John Deere’s cotton farming equipment such technological jewels were born in Vardeman’s own shop. It was a privilege to tour the farm and the shop guided by Buzz himself and to listen to him explain to the students how an idea that flourishes in a determined mind can change the world. Buzz’s ideas have been flourishing for decades and have indeed changed the world far beyond his farm in West Texas.

Figure 1. Texas plains cotton.

Figure 2. Vardeman Farm

Figure 3. Lubbock Cotton Growers Co-op Gin.

Figure 4. USDA-AMS Lubbock Classing Office + Plains Cotton Growers, Inc. (PCG).

Figure 5. Texas Tech Fiber & Biopolymer Research Institute.

2014: Dr. Shalene Jha, Dept. of Integrative Biology

How human-altered landscapes influence native plant and pollinator populations

This study had two main objectives: 1) identification and curation of 30,000 native pollinators collected from more than 40 study sites across Texas, plus a pollen reference library with more than 70 native plant species, and 2) to develop outreach materials that illustrate native pollinator diversity, ecology, and conservation strategies. This will allow us to examine the pollen preferences of pollinator species across distinct regions and land use types (e.g., natural areas and cities). For the second objective, we created a habitat and foraging database for all pollinators in our collection so we could demonstrate to the public the importance of conserving a variety of nesting and foraging habitats for effective native pollinator conservation. Specifically, we illustrated the importance of conserving nesting and foraging habitats in a series of pollinator outreach documents. These outreach materials are in both English and Spanish and include a photographic species list per site, including life-history traits, and a description of the habitat required by common species. Given that pollinator loss can dramatically reduce native plant reproduction, we hope to use our research insights to identify critical pollinators for Texas native plants and share information on how to best conserve habitat for diverse and abundant native pollinator communities.

Figure 1. Undergraduate researcher curating a box of native bees.

Figure 2. Photographic list of native bee species for Balcones Canyonlands National Wildlife Refuge.

Figure 3. Material describing native bee habitat.

Figure 4. Accompanying native bee species and habitat information in Spanish.