Life Sciences Commons^™

Recovery Of Vegetation Following A Wildfire In A Barrier Island Grassland, Padre Island National Seashore, Texas, Robert I. Lonard, Frank W. Judd, Elizabeth H. Smith, Chenghai Yang

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Vegetation recovery following a wildfire in vegetated flats and secondary dunes of Padre Island National Seashore, Texas, was studied from January 2000 to January 2002. Species richness, diversity, evenness, abundance, and importance were evaluated. Species richness, diversity, and evenness were restored quickly in vegetated flats (51 days) and secondary dunes (71 days). The burned secondary dune site had the same dominant species as its non-burned counterpart from the beginning to the end of the study, but it took 106 days for the dominant species to be restored in the burned vegetated flats. No exotic species established in burned sites. Two …

Potential Of Modis Ocean Bands For Estimating Co2 Flux From Terrestrial Vegetation: A Novel Approach, Abdullah Rahman, Vicente D. Cordova, John A. Gamon, Hans Peter Schmid, Daniel A. Sims

School of Earth, Environmental, & Marine Sciences Faculty Publications

A physiologically-driven spectral index using two ocean-color bands of MODIS satellite sensor showed great potential to track seasonally changing photosynthetic light use efficiency (LUE) and stress-induced reduction in net primary productivity (NPP) of terrestrial vegetation. Based on these findings, we developed a simple ‘‘continuous field’’ model solely based on remotely sensed spectral data that could explain 88% of variability in flux-tower based daily NPP. For the first time, such a procedure is successfully tested at landscape level using satellite imagery. These findings highlight the unexplored potential of narrow-band satellite sensors to improve estimates of spatial and temporal distribution in terrestrial …

Community Ecology Of Freshwater, Brackish And Salt Marshes Of The Rio Grande Delta, Frank W. Judd, Robert I. Lonard

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Species composition and importance, species diversity and evenness, species richness, and community similarity are compared among 6 freshwater, 9 brackish and 11 salt marshes in the Rio Grande Delta. Community similarity is generally low among marshes, but salt marshes have a greater mean coefficient of similarity than brackish marshes. Species richness per marsh ranges from 15 to 31 for freshwater marshes, 7 to 24 for brackish marshes and 7 to 26 for salt marshes. Each freshwater marsh has a different dominant species. The first six species in importance in all three kinds of marshes contribute from 72.6 to 99.8% of …

The Vascular Flora Of The Palo Alto National Battlefield Historic Site, Cameron County, Texas, Robert I. Lonard, Alfred T. Richardson, Norman L. Richard

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

A checklist is provided of the vascular plant taxa of the 1,376 ha Palo Alto Battlefield National Historic Site (PABNHS) in Cameron County of south Texas. PABNHS consists of four plant communities: resacas and tanks, salt flats, brush-grasslands and coastal marshes. Vascular plants of disturbed sites are noted. Two hundred forty-three taxa in 66 families are documented and their community affiliations are given. Three families, Poaceae, Asteraceae and Fabaceae contain 37.5% of the species richness at PABNHS.

Hooded Oriole Nest Failure Associated With A Novel Nest Site, Kevin Ellison, Timothy Brush

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Ecological traps occur where species are attracted to use a resource that exposes them to greater than normal risk of mortality or reproductive failure. We observed complete failure of Hooded Oriole (Icterus cucullatus) nests in streetlights in a south Texas suburb where use of such nest sites was relatively common. This is of concern as streetlights functioned essentially as traps: orioles built their nests within them but all these nests failed, evidently because the eggs were exposed to lethal temperatures. Moreover, Hooded Oriole nesting success on all other substrates in this area was low (31%, n -- 69). Therefore, sufficient …

Evaluation Of Artificial Lighting Sources For The Acquisition Of Color Infrared Imagery Under Glasshouse Conditions, Kenneth R. Summy, Christopher R. Little, Ruben A. Mazariegos, Diana Lee Hinojosa-Kettelkamp, Jeri Carter, Shireen Yousef, Robert Valdez

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

English: Research was conducted to evaluate the spectral properties, illumination intensities and lighting patterns of four basic categories of bulbs and lamps which could conceivably serve as sole lighting sources for the acquisition of color infrared (CIR) imagery under glasshouse conditions. Bulbs and lamps in two major categories (fluorescent tubes and sodium- and mercury-vapor glasshouse lamps) were deemed unsuitable for this purpose either because they emitted little or no nearinfrared (NIR) radiation or because they imparted an overall bluish cast that seriously degraded the quality of CIR imagery. All of the incandescent and quartz halogen lamps evaluated in these studies …

Regional Ecological Resource Assessment Of The Rio Grande Riparian Corridor: A Multidisciplinary Approach To Understanding Anthropogenic Effects On Riparian Communities In Semi-Arid Environments, Jay Raney, Amy Neuenschwander, Frank W. Judd, Gene Paull, Melba Crawford, Robert I. Lonard, Tatiana Encheva, Thomas Tremblay, William White

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Riparian ecosystems of the Southwestern United States are among the most productive ecosystems of North America. The rapid decline of these ecosystems throughout the United States, including the Lower Rio Grande Valley, has made riparian conservation a focal issue. This was a multidisciplinary study of riparian communities along the Lower Rio Grande Valley of Texas and Mexico. The objectives of this research project were to: (1) acquire and analyze high-resolution, remotely sensed data from multiple sensors; (2) integrate existing and new field data and remotely sensed data into a geographic information system (GIS); (3) ascertain whether the native vegetation communities …

Factors Controlling Seagrass Revegetation Onto Dredged Material Deposits: A Case Study In Lower Laguna Madre, Texas, James E. Kaldy, Kenneth H. Dunton, Joseph L. Kowalski, Kun-Seop Lee

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Our objective was to evaluate the influence of water quality and sediment chemistry on the survival and growth of Halodule wrightii transplanted onto unconsolidated dredged materials in Lower Laguna Madre, TX. Subsequent to transplanting activities, we measured environmental conditions and seagrass parameters at transplant and natural beds over a 1-yr period. Although water quality characteristics at the transplant and comparison sites were compatible with seagrass growth, transplants failed to survive for more than a few months. Seagrasses at natural sites received high light (>6000 mols m−2 y−1) and exhibited typical patterns of annual growth, biomass and density as well …

Breeding Abundance And Nest-Site Distribution Of The Altamira Oriole At Santa Ana National Wildlife Refuge, Texas, Timothy Brush, Christopher R. Hathcock

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

The distribution of the Altamira oriole (Icterus gularis) in the United States is restricted to the Lower Rio Grande Valley of southernmost Texas. Our objective was to assess the current breeding status of this species at and near Santa Ana National Wildlife Refuge (SANWR), a principal nesting area in the region. During each breeding season from 1997 to 1999, we attempted to find and monitor all Altamira oriole nests in and within 0.5 km of SANWR to determine annual breeding-pair abundance, annual nest-site distribution, and nest distribution among tree species. We estimated that there were 6 or 7, 8 or …

A Guide To Growing Healthy Trees In The Lower Rio Grande Valley, Valley Proud Environmental Council, Texas Forest Service, Texas Urban Forestry Council, Brownsville Public Utilities Board, Brownsville Beautification Committee, Joe Ideker, Steve Benn, Beau Hollingsworth, Chris Best, Robert I. Lonard

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

No abstract provided.

Breeding Distribution And Habitat Use Of Audubon's Oriole In The Lower Rio Grande Valley Of Texas, Steven Gerald Monk

Theses and Dissertations - UTB/UTPA

Audubon's Oriole ( Icterus graduacauda ) was known historically throughout the Lower Rio Grande Valley (LRGV) of Texas, but its breeding range has now declined to mainly riparian habitat in Starr County. Habitat loss, degradation, and fragmentation, and brood parasitism by Bronzed Cowbirds ( Molothrus aeneus ) are likely causes of this decline. Habitat patches where Audubon's Orioles were present were larger, with a larger vertical range of canopy, greater vegetation volume, greater richness of bird and woody plant species, less local deforestation, and less local habitat fragmentation than where Audubon's Orioles were absent. Bronzed Cowbirds showed no numeric correlation …

Recovery Of Vegetation Following A Wild Fire On The Margins Of Tidal Flats, Padre Island National Seashore, Texas, Robert I. Lonard, Frank W. Judd, Elizabeth H. Smith

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Recovery of halophytic vegetation on the margin of tidal flats following a wildfire at Padre Island National Seashore, Texas, was studied for 26 months. Species richness, species diversity, species importance, evenness and vegetation abundance were evaluated. Species richness and diversity were restored within 108 days after the fire. Sporobolus virginicus was the dominant species on both burned and non-burned transects. Vegetative cover was slow to recover. It took 19 months for cover of burned areas to equal or exceed cover of non-burned areas. Biomass also was slow to recover and it did not equal biomass of non-burned transects in 26 …

Phenology Of Acacia Berlandieri, A. Minuata, A. Rigidula, A. Schaffneri, And Chloroleuconebano In The Lower Rio Grande Valley Of Texas During A Drought, Melissa R. Eddy, Frank W. Judd

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Flowering and fruiting phenology of Acacia berlandieri, A. minuata, A. rigidula, A. schaffneri, and Chloroleucon ebano were studied at 3 sites in the Lower Rio Grande Valley of Texas from July 1998 through August 1999. Severe drought conditions prevailed for the 6 months preceding this study, and rainfall was 20% lower during the study than the long-term mean. Acacia berlandieri had the longest flowering period (5 months); each of the other 3 Acacia species flowered for 3 months. All of the Acacia species flowered in winter or spring (at relatively low temperatures and increasing photoperiod). Peak flowering occurred in February …

Aerial Detection Of Waste Disposal Sites Near Donna Reservoir In South Texas., C. F. Webster, James H. Everitt, D. E. Escobar, M. R. Davis

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Aerial color-infrared (CIR) photography was used to detect and catalog unauthorized solid waste disposal sites around Donna Reservoir in the Lower Rio Grande Valley (LRGV) of southern Texas. Qualitative visual evaluation of the positive transparencies showed 25 possible disposal sites randomly scattered throughout the study area, located in sites ranging from bare soil to grass and mixed brush/woods. These sites were transposed onto a computer-generated area map for ground survey confirmation and use by organizations planning to clean-up the sites. Ground-truthing was used to identify waste contents at each site and to estimate waste volumes and areas covered. Unauthorized solid …

Access To Credit, Plot Size And Cost Inefficiency Among Smallholder Tobacco Cultivators In Malawi, Gautam Hazarika, Jeffrey Roger Alwang

School of Economics and Finance Faculty Publications

Using data from the Malawi Financial Markets and Household Food Security Survey, this paper examines the effect of access to credit from formal sources, and tobacco plot size, on cost inefficiency among Malawian smallholder tobacco cultivators. Farm-specific cost inefficiency is estimated within the framework of stochastic frontier analysis. Access to credit is measured as the sum of household members' self-reported credit limits at credit organisations, arguably a truer measure of an exogenous credit constraint than credit program participation or actual loan uptake. It is found that tobacco cultivation is significantly less cost inefficient per acre on larger plots. While access …

Chorionic Morphology Of Mayfly (Ephemeroptera) Eggs Of The Lower Rio Grande Valley, Maria D. De Leon

Theses and Dissertations - UTB/UTPA

External egg morphology of ten species of Lower Rio Grande Valley (LRGV) mayflies are compared using scanning electron microscopy (SEM) and a taxonomic key to the eggs is provided. The eggs of five species are described here for the first time. Preserved female adults or subadults were critical-point dried using liquid CO2 . The eggs were removed and placed on metal stubs for sputter coating with gold/palladium. The coated eggs were then observed and photographed by SEM. The morphological features described were the chorionic sculpturing, polar caps, accessory attachment structures, and micropyles. This is the first mayfly egg comparison and …

Comparison Of Native Brushland, Replanted, And Unaided Secondary Succession Plant Communities In The Lower Rio Grande Valley Of Texas, Mitchell Allen Sternberg

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Agriculture and urban development have destroyed 95% of native brushland habitat in the Lower Rio Grande Valley (LRGV) of south Texas. Therefore, habitat restoration is an important issue in the LRGV. Since 1982, the U.S. Fish and Wildlife Service has been replanting areas in the LRGV to native brushland species to establish a wildlife corridor along the lower reach of the Rio Grande. Vegetation composition of a mature brushland, a replanted habitat and an unaided secondary succession site (fallow field) were examined at one locale in the LRGV in 1999. The mature brushland edge plot had the highest species richness …

An Overview Of Aircraft Remote Sensing In Integrated Pest Management, James H. Everitt, Kenneth R. Summy, D. E. Escobar, M. R. Davis

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

English: This paper presents four exemplary applications of aerial photography and videography, global positioning system (GPS), and geographic information system (GIS) technologies for detecting, monitoring, and mapping insect infestations in agriculture, forestry, and rangeland areas. Applications demonstrated include detecting and mapping: (1) citrus blackfly (Aleurocanthus woglumi Ashby) infestations in citrus orchards; (2) silverleaf whitefly (Bemisia argentifolii Bellows and Perring) infestations in cotton; (3) harvester ant (Pogonomyrmex barbatus F. Smith) infestations on rangelands; and (4) western pine beetle (Dendroctonus brevicomis LeConte) infestations in a forested area. The integration of a GPS with the video imagery permitted latitude and longitude coordinates of …

Synthetic Lethal Analysis Implicates Ste20p, A P21- Activated Protein Kinase, In Polarisome Activation, April S. Goehring, David A. Mitchell, Amy Hin Yan Tong, Megan Keniry, Charles Boone, George F. Sprague Jr.

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

The p21-activated kinases Ste20p and Cla4p carry out undefined functions that are essential for viability during budding in Saccharomyces cerevisiae. To gain insight into the roles of Ste20p, we have used a synthetic lethal mutant screen to identify additional genes that are required in the absence of Cla4p. Altogether, we identified 65 genes, including genes with roles in cell polarity, mitosis, and cell wall maintenance. Herein, we focus on a set that defines a function carried out by Bni1p and several of its interacting proteins. We found that Bni1p and a group of proteins that complex with Bni1p (Bud6p, Spa2p, …

Detecting Stress In Glasshouse Plants Using Color Infrared Imagery: A Potential New Application For Remote Sensing, Kenneth R. Summy, Christopher R. Little, Ruben A. Mazariegos, James H. Everitt, M. R. Davis, J. V. French, A. W. Scott Jr.

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

English: Studies were conducted to evaluate the effectiveness of color infrared (CIR) film for detecting physiological stress in plants located within glasshouse structures. Spectroradiometer measurements obtained within and outside of a structure constructed of polycarbonate plastic indicated no significant attenuation or disruption of visible and near-infrared radiation entering the structure. CIR photographs of cucumber seedlings (Cucumis sativus) obtained within the greenhouse were comparable in quality to those obtained outside the structure, and clearly distinguished between foliage of healthy plants and those subjected to a moderate level of nitrogen stress. In CIR imagery of a trifoliate orange tree (Poncirus trifoliata (L.) …

Cissus Sicyoides C. Linnaeus (Vitaceae), A Potential Exotic Pest In The Lower Rio Grande Valley, Texas, J. V. French, Robert I. Lonard, James H. Everitt

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

English:Cissus sicyoides C. Linnaeus, a perennial vine native to tropical Mexico, Central America, and the Caribbean, has recently been rediscovered in the Lower Rio Grande Valley,Texas. A dense population of this exotic species has been located in a brushy area along a canal network and in two adjacent citrus groves near Weslaco. This species produces a dense mantle that covers other vegetation, appears to be invasive, and may pose a potential weed problem in citrus in the Lower Rio Grande Valley.

Spanish: Cissus sicyoides C. Linnaeus, una enredadera perene nativa de los trópicos de México, América Central y el Caribe, …

First Nesting Attempt Of Yellow-Faced Grassquit (Tiaris Olivacea) In The United States, Timothy Brush

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

No abstract provided.

Riparian Vegetation Of The Lower Rio Grande, Robert I. Lonard, Frank W. Judd

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

The riparian vegetation of the lower reach of the Rio Grande was studied at 7 locations using 3 line intercepts at each location. There were no trees at the mouth of the river and the vegetation was similar to that found along the Laguna Madre shore of barrier islands. Mesquite (Prosopis glandulosa) was the dominant tree near the coast and in the western section of the river near Falcon Dam. Sugar hackberry (Celtis laevigata) was the dominant tree species at all other sites except at Santa Ana National Wildlife Refuge, where cedar elm (Ulmus crassifolia) and anacua (Ehretia anacua) were …

Effects Of Ethanol On The Toxicity And Metabolism Of Acetonitrile And Acrylonitrile, Nancy Ochoa-Garza

Theses and Dissertations - UTB/UTPA

This study examined the effects of ethanol on the toxicities and metabolism of two aliphatic nitriles: acetonitrile and acrylonitrile (one unsaturated and one saturated aliphatic nitrile, respectively) in male Sprague-Dawley rats at four different time intervals. Toxicity signs were apparent in all animals given the nitrile dosage, but those treated with ethanol dosages showed signs of toxicity earlier than those treated with glucose dosages. Both of the nitrites were metabolized to cyanide and thiocyanate. The concentration levels of each metabolite was apparent at 2 and 3 g/kg ethanol dosage for acetonitrile and 3 and 4.5 g/kg ethanol dosage for acrylonitrile …

Effect Of Guanosine Tetraphosphate On Growth Rate And Stable Rna Synthesis In Escherichia Coli, Heather Anne Quintanilla

Theses and Dissertations - UTB/UTPA

Guanosine tetraphosphate (ppGpp) is a good candidate for a stable RNA synthesis regulator at different growth rates because: high ppGpp levels present during the stringent response are known to inhibit stable RNA synthesis, and there is an inverse correlation between ppGpp concentration and stable RNA synthesis at different growth rates. A system was constructed allowing the user to control intracellular ppGpp levels within the range characteristic of exponentially growing strains, while not allowing cells to adjust ppGpp in response to environmental changes. E. coli strains were transformed with a plasmid containing a truncated relA allele to provide ppGpp. Results show …

Ocelot Distribution In The Lower Rio Grande Valley National Wildlife Refuge, Kevin James Shinn

Theses and Dissertations - UTB/UTPA

Weaver hair-snaring surveys were conducted at 125 sites on 27 Refuge tracts to obtain information about the distribution and population status of the endangered ocelot ( Leopardus pardalis ) in the Lower Rio Grande Valley National Wildlife Refuge. The surveys resulted in 33.6% of the pads “hit”, including 8 by ocelot and 29 by bobcat. There was no significant difference in the number of ocelot hits between warm and cool seasons or between the sexes. Preferred habitat consists of dense thornscrub brush. Four species, snake-eyes, granjeno, honey mesquite, and colima comprise 50% or more of the total cover at each …

Evaluation Of Facilitated Succession At Las Palomas Wildlife Management Area In South Texas., Frank W. Judd, Robert I. Lonard, Gary L. Waggerman

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

This study examined the effectiveness of re-vegetation efforts which have been ongoing in the Lower Rio Grande Valley of Texas since 1958. Species composition, richness and diversity were evaluated in an undisturbed native woodland, a site planted with late successional species in 1961 (facilitated succession) and a farm field abandoned in 1974 (unaided succession) in northwestern Cameron County. Species richness and diversity for both trees and shrubs were greatest in the native woodland site. While there was greater similarity in species composition between the native woodland and the facilitated succession sites, species diversity in the tree and shrub layers of …

Identification Of A Genetic Locus Involved In Ppgpp Metabolism In Escherichia Coli, Roxanne Enid Garza

Theses and Dissertations - UTB/UTPA

Two genes involved in the metabolism of ppGpp are relA and spoT . A relX mutant has altered ppGpp levels, so relX may be a regulator of the RelA or SpoT enzymes. The growth of the relX mutant has been reported to be both temperature and leucine sensitive. It was discovered in this work that this relX mutant is not temperature sensitive, however it is leucine sensitive. The original goal was to study effects of the relX gene on ppGpp metabolism. During the process of mapping the relX gene, it was discovered that the leucine sensitivity was caused by some …

Parallelism In Digging Behaviour In Two Distantly Related Decapod Crustaceans, Zen Faulkes

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Walking and swimming are the most common forms of locomotion used routinely by decapod crustaceans, but some have evolved ways of locomoting throughsubstrates, notably sand. Two such digging species, of different infraorders, are spanner crabs (Ranina ranina; Brachyura) and spiny sand crabs (Blepharipoda occidentalis; Anomura). Videotape and electromyogram analysis showed that digging by these species is similar, but Raninahas a wider locomotor repertoire than Blepharipoda: for instance, Raninacan walk forward on the benthos, whereas Blepharipoda(and other sand crabs) cannot walk. Similarly, although both Raninaand Blepharipodadig into the sand using their legs and abdomen, leg movements of Raninaare less stereotyped than …

Habitat Use, Population Density, And Home Range Of Elf Owls (Micrathene Whitneyi) At Santa Ana National Wildlife Refuge, Texas, Christopher Michael Gamel, Timothy Brush

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

We collected data on the habitat use, home range size, and population density of the Elf Owl (Micrathene Whitneyi Idonea) in the Santa Ana National Wildlife refuge (SANWR) Lower Rio Grande Valley, Texas. Fourteen nocturnal surveys in 1995 and 1996 indicated that Elf Owls used chaparral habitat (92%) more than riparian woodlands(8%). Habitats used had high foliage densities(greatest density = 2.5-3.0 m) with partial canopies (x = 3.8 +_ 0.36 m [+_SE] and semi-open understories (greatest density< 1 m). Unused chaparral habitat lacked high canopy coverage and had a denser understory, while riparian woodlands had greater canopyheights (• = 5.25 m) and open understories. Home range size determined by radiotelemetry averaged1.0.5+_0.33 ha (range = 0.24-2.60, N = 9). We estimated the maximum potential population size in SANWR to be 802 Elf Owls, assuming a home range size of 1.05 ha per breeding pair and saturation of preferred habitat.

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Colectamos datos sobre el uso de habitat, tamafio del rango de hogar y densidad poblacional de Micrathene whitneyi idonea en el Refugio …