Digital Commons Network^™

South Texas Wildlife Activity Across A Fragmented Landscape And Road Mitigation Corridor, Caitlin K. Brett

Theses and Dissertations

Wildlife crossing structures (WCS) and roadside fencing are commonly installed to mitigate habitat fragmentation, wildlife road mortalities, and other negative effects that roads can have on the surrounding landscape. Eight such WCS were constructed below Farm-to-Market (FM)106 in Cameron County, Texas, across a 16 km corridor transecting the Laguna Atascosa National Wildlife Refuge. These WCS, paired with adjacent roadside fencing, were intended to prevent road mortalities of the endangered ocelot (Leopardus pardalis) and to mitigate the barrier effect of FM106 on this and other meso-mammal species. This study will analyze camera trap data from roadside and habitat reference …

Influence Of Pretreatments On Physiological Status And Post-Planting Survival Of Thornforest Seedlings In A Restoration Context, Douglas E. Mainhart

Theses and Dissertations

Semi-arid ecosystems across the globe have faced land conversion posing a threat to the important ecosystem services they provide. Revegetation-centered restoration efforts in arid regions have low success due to limited water availability and higher temperatures. Typically, practitioners utilize methods that modify field conditions around seedlings to mitigate these stressors. I evaluated the efficacy of in-nursery treatments to improve plant water status. Three pretreatments were applied: elevated CO2, drought hardening, and an antitranspirant foliar spray. My goal was to understand how these pretreatments would impact survival and growth in the field and what physiological traits they altered. Elevated CO2 and …

Effects Of Disturbance (Mowing) On Florivory And Floral Defenses In Solanum Elaeagnifolium, A Noxious And Worldwide Invasive Weed, Alejandro Rafael Vasquez Marcano

Theses and Dissertations

Chapter 1: Literature Review- In this literature review we have examined weed management as it concerns urban and agricultural ecosystems, as well as the need for mowing assessments as it relates to floral traits and defense against herbivory.

Chapter 2: Experiments- In the experiments we examined the role of mowing on floral growth traits, floral defense traits, and their effect on Manduca sexta specialist herbivores.

Chapter 3: Results- In the results we found SLN flowers to have larger diameters than unmowed flowers; however, flower mass was in line with our predictions as unmowed flowers were heavier in high mowing frequency …

Tree Ring Reconstructions Of Streamflow For The Lower Rio Grande Valley Of Texas, Adedolapo Mutiyat Adeyanju

Theses and Dissertations

The Rio Grande River is a major water source for people living within the USA-Mexico border. The Rio Grande River has its headwaters in the San Juan Mountains in Colorado and the Sierra Madre Occidental in Mexico before flowing into Texas through El-Paso. The water supply issues facing the Lower Rio Grande Basin (LRGB) are extremely complex from international restrictions to severe climate change. The river shares its flow between the U.S.A and Mexico based on the provisions of the 1944 treaty between the U.S.A and Mexico. The LRGB flow is regulated by releases from Falcon and Amistad Reservoirs managed …

De Novo Transcriptome Analysis Of Orange Jasmine (Murraya Paniculata) Infected With Citrus Greening Disease, Jeffrey Aquino Gomez

Theses and Dissertations

Citrus greening disease, also known as Huanglongbing, is one of the most devastating citrus diseases in the world. Candidatus Liberibacter asiaticus (CLas) is a non-culturable, phloem-limited bacterium that serves as one of two vectors for the transmission of any of the three kinds of greening disease. In cooler climates, the African variant transmitted by the African citrus psyllid (Trioza erytreae) is more prevalent. The Asian form transmitted by the Asian citrus psyllid (Diaphorina citri) where is predominant in warmer conditions and recently discover the American form who is also transmit by Diaphorina citri, was discover in Brazil but has also …

Examination Of The Realized Host Range Of North American Lacebug (Gargaphia Arizonica Drake & Carvalho) And Texas False Potato Beetle (Leptinotarsa Texana Schaeffer) As A Potential Biocontrol Agents For Silverleaf Nightshade (Solanum Elaeagnifoli Cav.), Samikshya Subedi

Theses and Dissertations

Silverleaf nightshade (Solanum elaeagnifolium Cav.) is a perennial forb native to South Texas and Central and South America, but it has become a serious agricultural weed across the world. Because silverleaf nightshade (SLN) is difficult and expensive to manage using chemical and mechanical controls, there is growing attention and research focused on biological control options. In this project, we used both field and laboratory studies to examine the suitability of two North American insects, namely North American lacebug (Gargaphia arizonica Drake & Carvalho) and Texas false potato beetle (Leptinotarsa texana Schaeffer) as prospective biological control agents for …

Revealing The Effects Of Climate Change And Fungicides On Soil Microbial Communities In The Lower Rio Grande Valley, Texas, Armida Rivera

Theses and Dissertations

Fungicide applications are effective to prevent fungal pathogens that are known to cause crop damage and decrease yields. However, these pesticides can exert toxic or inhibitory effects on non-targeted organisms such as soil microbial communities. In addition, it is unknown to what extent shifts in temperature and soil moisture resulting from global climate change, alter the activities of non-targeted soil organisms. The aim of this study was to evaluate soil biological parameters such as soil respiration and enzyme activities involved in the cycling of carbon, nitrogen, and phosphorous (Beta-glucosidase, Fluorescein Diacetate (FDA) Hydrolysis, urease, alkaline phosphatase, acid phosphatase, and N-acetyl-Beta-glucosaminidase) …

Harvester Ant (Pogonomyrmex Sp.) Seed Preferences And Distribution In A Suburban Setting, Lilly V. Elliott

Theses and Dissertations

Harvester ants (Pogonomyrmex sp.) are omnivorous ants native to Texas and are the main food source for the threatened Texas Horned Lizard (Phrynosoma cornutum). Little research has been conducted on harvester ants in the Lower Rio Grande Valley (LRGV) and their interactions with their environment. For this purpose, a variety of experiments were conducted to better understand these interactions and preferences. In CHAPTER I, suburban harvester ants were exposed commonly used cover crop seeds in the LRGV and inoculated seeds via seed depots over the course of 24 hours. We found that harvester ants do …