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Life History and Case Building Behaviors of Phylloicus ornatus (Banks) (Trichoptera: Calamoceratidae) In Two Spring Fed Tributaries in the Central Edwards Plateau Bioregion of Texas

Description: The life history and case-making behaviors of Phylloicus ornatus from two springfed first order streams in the Edwards Plateau Bioregion of Texas were studied from January 1998 to November 1999. Field larval, pupal and adult samples and laboratory rearings indicated a multivoltine cycle. First instars differ from late instars in number of labral setae and in having a unique spur-like claw on each lateral hump. Larval development was asynchronous with second through fifth instars and pupae present most months. First instars were present April through July, October and November. Case making of first instar and case reconstruction of later instars extracted from their cases was documented by videophotography.
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Date: August 2000
Creator: Norwood, James Christopher

Spatial and Temporal Influences of Water Quality on Zooplankton in Lake Texoma

Description: Seventy-one aquatic species including the copepodids and nauplii were identified from Lake Texoma from August 1996 to September 1997. Zooplankton community structure, abundance and spatial and temporal distributions were compared among five lake zones delineated a priori based on chloride concentration. The zones, in order of decreasing chloride concentration, are the Red River zone (RRZ), Red river Transition zone (RRTZ), Main Lake zone (MLZ), Washita River Transition zone (WRTZ) and Washita River zone (WRZ). Bray Curtis Similarity Index showed community structure was most similar in the two Red River arm zones, the two Washita River arm zones and the MLZ. Zooplankton abundance was greatest in the Red River arm (312 org/L), intermediate in the Washita River arm (217 org/L) and least in the Main Lake body (103 org/L). A significant increase in the abundance of a deformed rotifer, Keratella cochlearis, was observed mainly in the Red River arm during a second study from March 1999 to June 1999. Seasonal dynamics, rather than spatial dynamics, were more important in structuring the zooplankton community, especially in the two river arms. Spatial variance was solely attributed to station and zone effects independent of time for a few crustacean species and many of the water quality parameters supporting the presence of longitudinal gradients of differing water quality. Three independent models (Red River arm, Washita River arm, Main Lake body) rather than a single model for the entire reservoir, best describe patterns in the zooplankton community and its relationship to seasonal, physical and chemical factors. Statistical power, sample size and taxonomic resolution were examined. When monitoring seasonal and annuals trends in abundance, the greatest statistical power was achieved by analyzing count data at taxonomic levels above genus. Taxonomic sufficiency was assessed to determine if costs could be reduced for zooplankton identifications. For water quality monitoring ...
Date: May 2000
Creator: Franks, Jessica L.

Biodiversity of Dragonflies and Damselflies (Odonata) of the South-Central Nearctic and Adjacent Neotropical Biotic Provinces

Description: The south-central United States serves as an important biogeographical link and dispersal corridor between Nearctic and Neotropical elements of western hemisphere odonate faunas. Its species are reasonably well known because of substantial collections, but there has been no concerted effort to document the extent of biodiversity and possible geographic affinities of dragonflies and damselflies of this region. The recent discoveries of Argia leonorae Garrison, Gomphus gonzalezi Dunkle and Erpetogomphus heterodon Garrison from southern and western Texas and northern Mexico suggest that Odonata species remain to be discovered in this area, particularly from far south Texas and northern Mexico. I have documented a total of 12,515 records of Odonata found in 408 counties within the south-central U.S. A total of 73 species of damselflies and 160 species of dragonflies was revealed in the region. The 233 (197 in Texas) Odonata species are distributed among 10 families and 66 genera. Illustrated family, generic, and species-level keys are provided. Since the beginning of this work in the Fall of 1993, one species has been added each to the Louisiana and Oklahoma faunas, and 12 species have been added, previously unreported from Texas, including four new to the U.S. The area of highest Odonata biodiversity overall (161 spp.) is in the Austroriparian biotic province. The greatest degree of faunal similarity between the south-central U.S. and other intra-continental regions was observed for the eastern (64%) United States. Diversity is a function of area, and as expected, the numbers of breeding birds and Odonata, in each contiguous U.S. state are positively correlated (r=0.376, n=33, p=0.031). There is, however, no strong correlation between land area and species diversity within the region, but those natural biotic provinces (Austroriparian, Texan, Balconian) where aquatic systems and topographic heterogeneity are the greatest provide a broader spectrum of potential Odonata habitats and ...
Date: May 1999
Creator: Abbott, John C.

A Comparison of Predicted and Actual Trophic Status of Lake Ray Roberts, Texas Based on Chlorophyll A

Description: Two years before impoundment, the trophic status of Lake Ray Roberts was predicted by applying the total phosphorus input into the Organization for Economic Cooperation and Development (OECD) eutrophication model. Predicted mean summer epilimnetic (MSE) chlorophyll a of Elm Fork arm, Isle duBois arm and Main Body were in the eutrophic category of the OECD model. Observed MSE chlorophyll a two years after impoundment of Elm Fork arm, Isle duBois and Main Body had not reached their predicted means and were at the mesotrophic-eutrophic boundary of the OECD model. Six years after impoundment, observed MSE chlorophyll a for Main Body, was closer to its predicted mean and in the eutrophic category of the OECD model. Six years after impoundment, Elm Fork arm was the most productive area of Lake Ray Roberts. Observed means of chlorophyll a, total phosphates, suspended solids and turbidity were often highest in the Elm Fork arm. Wastewater effluent from Gainesville and Valley View, TX, had an impact on productivity in Elm Fork arm.
Date: May 1999
Creator: Lytle, Lili Lisa

The Effects of Organic Surface Amendments on Soil Nutrients and Initial Tree Establishment

Description: This study examined the effects of replicating woodland soil surface horizonation on the nutrient status of underlying soils and the initial establishment and growth of trees. A total of 283 container grown trees were planted in a bufferzone around a future landfill site. Control amendments consisted of an 8 cm layer (0.5 m3) of wood chips applied in a circular area of 4.6 m2 around the trees' planting pit. For the treatment, a 2.5 cm layer of composted biosolids (0.15 m3 or 80 Mg/ha) was applied in a circular area of 4.6 m2 around the trees' planting pit followed by an 8 cm layer (0.5 m3) of wood chips. The results indicate that the replication of woodland soil surface attributes using composted biosolids can significantly improve the nutrient status of underlying soil. Some significant effects were seen under control conditions, too. However, the effects on tree establishment and growth parameters were, for the most part, not statistically significant.
Date: May 1999
Creator: Thuesen, Kevin (Kevin Andrew)

Ecological Association Between the Red-Cockaded Woodpecker and Southern Pine Beetle in the Homochitto National Forest: a Geographic Information System Approach

Description: Since the introduction of management practices by the Forest Service to stabilize red-cockaded woodpecker (RCW) populations, the number of cavity trees killed by southern pine beetles (SPB) has increased. A model of the landscape ecology of RCW and SPB in the Homochitto National Forest was created using data collected from the Forest Service and Global Atmospherics. The conclusions of the study were that the RCW and SPB utilize the same type of habitat and the stand hazard maps are an accurate means of determining the locations of SPB infestations. The functional heterogeneity maps created for the SPB and RCW would be useful predictors of future occurrences of either species if complete data were obtained.
Date: December 1998
Creator: Skordinski, Karen R. (Karen Renee)

Biogeographic Relationships of Pocket Gophers (Geomys breviceps and Geomys bursarius) in the Southeastern Portion of Their Ranges

Description: This research utilized population genetic analyses (protein starch-gel electrophoresis and DNA sequencing of the cytochrome b mtDNA gene), host-parasite specificity (lice coevolution), remote sensing of satellite data, and geographic information systems (GIS) to characterize newly discovered populations of pocket gophers (genus: Geomys) in Arkansas. These populations are isolated and occur in seemingly unsuitable habitat in the Ozark Mountains of Arkansas. Analyses of electrophoretic and ectoparasite data suggested the populations in the Ozark Mountains represented isolates allied to Geomys bursarius, a species not known to occur in Arkansas. Comparison of mitochondrial DNA sequence data of the cytochrome b gene with that of other taxa and morphometric analyses confirmed that these populations are most closely allied to G. bursarius occurring to the north in Missouri. Moreover, these mtDNA sequence analyses indicated a degree of differentiation typical of that between other subspecies of pocket gophers. Therefore, these populations represent a distinct genetic entity in an intermediate stage of speciation and should be designated as a new subspecies, Geomys bursarius ozarkensis. Molecular clock analysis revealed a time of lineage divergence for this new subspecies as approximately 511,000 YBP. Due to the isolated nature and limited distribution of this subspecies, an evaluation of critical habitat needs was initiated. Remote sensing and GIS technologies were used to identify and describe suitable habitat Computerized classification of satellite imagery of suitable vegetation, integrated with ancillary digital information on soil associations, roads, and water systems, revealed that human activity had played a positive role in the establishment and dispersal of pocket gophers in this area. This research represents an initial combination of classical systematic tools with remote sensing and GIS to investigate biogeographic patterns and evolution. This project establishes a framework for using an interdisciplinary approach to studying organisms with limited distributions, determining evolutionary status, and providing recommendations for ...
Date: August 1998
Creator: Elrod, Douglas Allen

Documentation of Biodiversity Impacts (Including Cumulative Biodiversity Impacts) in Environmental Impact Statements

Description: In the United States, biodiversity impact assessment has historically received little attention. Responding in 1993, the Council on Environmental Quality (CEQ) released guidelines on incorporating biodiversity into environmental impact assessment under the National Environmental Policy Act of 1969. The objectives of the study here were to identify the level of documentation of biodiversity impact assessment in sample Environmental Impact Statements (EISs); identify whether in the years following the release of 1993 CEQ guidelines any significant changes have taken place in assessment of biodiversity; identify deficiencies, and if the need exists, formulate appropriate recommendations and approaches for addressing biodiversity in EISs. The study involved a systematic review of 30 EISs published since the release of CEQ guidelines, and five EISs published prior to it. The review involved answering a series of standard questions, which attempted to ascertain the level of biodiversity impacts included in each impact statement. Trends in approaches to biodiversity impact assessment were investigated and deficiencies summarized. The analysis resulted in a series of recommendations for improving the manner in which biodiversity impact assessment can be approached.
Date: August 1998
Creator: Bhatia, Sarika

Underwater Optical Properties of Lake Texoma (Oklahoma-Texas) Using Secchi Disk, Submarine Photometer, and High-Resolution Spectroscopy

Description: The underwater optical climate of Lake Texoma was measured at eleven fixed stations from August 1996 to August 1997. Secchi transparency and submarine photometry characterized seasonal and spatial values of secchi depth (SD), vertical attenuation coefficient (η''), and depth of euphotic zone (Zeu). Indices of Zeu:SD and η'' × SD were compared with universally applied values derived from inland and coastal waters. Turbidity explained 76% of the variation (p = 0.0001) of η'' among water quality parameters, including chlorophyll-α. Using a spectroradiometer, spectral signatures of chlorophyll-α and turbidity were located. Stations with low turbidity exhibited a distinct green reflectance peak around 590-610 nanometers, indicating presence of chlorophyll-α. Stations with high turbidity exhibited a reflectance peak shift towards the red spectrum, making it difficult to detect the chlorophyll signature. Derivative analysis of the reflectance signal at 590-610, and 720-780 nanometers allowed discrimination of this chlorophyll signature from those of turbidity (0.66 ≤ r^2 ≤ 0.99).
Date: August 1998
Creator: Rolbiecki, David A. (David Alan)

Development and Application of an Assessment Protocol for Watershed Based Biomonitoring

Description: With numerous bioassessment methodologies available, a regional protocol needs to be developed to ensure that results are comparable. A regional assessment protocol was developed that includes collecting five benthic macroinvertebrate samples, identifying organisms to genus, and calculating the following metrics: Number of Taxa, Total Number of Individuals, Simpson's Diversity Index, Shannon's Diversity Index, Percent Contribution of Dominant Taxa, Hilsenhoffs Biotic Index, and Percent Contribution of Dipterans. Once the protocol was developed, it was used to assess the Bayou Chico tributaries and watershed. All three tributaries had been significantly impacted by human activity as had the watershed as a whole. This study indicates that a regional protocol could be developed and is appropriate for biomonitoring at the watershed scale.
Date: May 1998
Creator: Schwartz, Joseph Howard

Biology and Energetics of Tropisternus Lateralis Nimbatus (SAY) (Coleoptera: Hydrophilidae) in a Playa on the Southern High Plains of Texas and Aquatic Coleoptera Diversity from Seven Playas on the Southern High Plains of Texas

Description: A study of the biology of Tropisternus lateralis, a hydrophilid beetle, was conducted during the flood period of a single playa on the Southern High Plains of Texas from early June 1995 through early September 1995. Mechanism of colonization, tolerance/avoidance to drought, larval density, and secondary production were analyzed. T. lateralis colonized playas from surrounding aquatic habitats and avoided drought through aerial dispersion. Once in the playa, larval density increased over time. Secondary production was 1.31 g/m2/.25 yr. In addition, aquatic Coleoptera diversity was studied in seven playas on the Southern High Plains of Texas. A total of twenty three species were identified from the study region. Nine species not reported in playa literature were identified.
Date: December 1997
Creator: Cook, Robert E. (Robert Edward), 1969-

Distribution of a Novel Gram Negative, Capsule-Forming Bacterium

Description: A novel Gram negative, capsule-forming bacterium was previously isolated in Dr. G. Roland Vela's laboratory. The distribution of this bacterium in soils from various locations was investigated. Soil samples from 188 locations around the world were examined. Isolates of the bacterium were obtained from 50 of these soils, with 48 of the isolates found in soils from the southwestern United States and northern Mexico. This suggests that this region is the natural habitat of the bacterium. The other two isolates were obtained from Madrid, Spain and Taipei, Taiwan. None were found in soils from South America or Australia. A lack of variation in morphology and physiological properties in the isolates suggests that a homogeneous population exists, even from widespread geographical locations.
Date: December 1997
Creator: Hughes, Roxana Bejarano

Life History of Mayatrichia ponta Ross (Trichoptera: Hydroptilidae) in Honey Creek, Turner Falls Park, Oklahoma

Description: The life history and ontogenetic microhabitat change of Mayatrichia ponta Ross were investigated in Honey Creek, Turner Falls Park, Murray Co., Oklahoma, U.S.A. from August 1994 to August 1995. The shape of larval cases changed from a small cone to a cylinder. M. ponta had an asynchronous multivoltine life history with considerable cohort and generation overlap; five generations were estimated. The development rate was reduced in winter. The winter generations of M. ponta had wider head capsule widths (136-165 μm) than summer generations (121-145 μm). The sex ratio of adults was 1.43 ♂ : 1 ♀. Fecundity ranged from 46 to 150 eggs/female. Fifth instar larvae and pupae aggregated on the bottom side of substrates. Early instars were distributed evenly on all sides of substrates. General patterns of ontogenetic microhabitat shift in aquatic insects are categorized as flow mediated, flow independent, and population interactions and other resources mediated.
Date: December 1997
Creator: Wang, Yi-Kuang

Light Spectra Distributions in Temperate Conifer-Forest Canopy Gaps, Oregon and in Tropical Cloud-Forest Canopy, Venezuela

Description: Light spectra distributions were measured in two different montane forests: temperate and tropical. Spectral light measurements were made in different sized canopy gaps in the conifer forest at H. J. Andrews Experimental Forest in Oregon, USA. Researchers at Oregon State University created these gaps of 20 m, 30 m, and 50 m in diameter. In the tropical cloud forest, spectral light measurements were made in two plots that were permanently established at La Mucuy Parque Nacional in Venezuela, in collaboration with researchers at Universidad de Los Andes. In both studies, spectra and distributions of physiologically active light were analyzed: red, far-red, R/FR ratio, and blue light.
Date: December 1997
Creator: Monteleone, Susan Elaine

Remote Sensing of Landscape-Level Ecological Attributes at Ray Roberts Lake in North Texas

Description: Biological diversity is a key component in assessing ecosystem health. Alteration, degradation and loss of habitat due to human influence is currently the primary stressor resulting in decreases in diversity. Reliable assessment of large areas in terms of biological integrity are needed for conservation and preservation efforts. Remotely sensed data provide an integrated view of reflected electromagnetic energy over large areas of the earth. These energy patterns provide unique spectral signatures which can be correlated to land cover and habitat. This research sought relationships between traditional ecological measures and information gathered from satellite digital imagery. Reliable interpretation of earth surface characteristics relies largely on accurate rectification to a map projection and subsequent thematic classification. Use of the Global Positioning System (GPS) for rectification was superior than digitizing topographical maps. Differentially corrected GPS locations provided optimum rectification with SPOT satellite imagery while marginally better rectifications were obtained for Landsat MSS imagery using uncorrected GPS positions. SPOT imagery provided more accurate land cover classifications than did MSS. Detection of temporal land cover change using MSS imagery was hampered by confusion among intermediate successional classes. Confusion between upland and bottomland forest classes occurred with both SPOT and MSS. Landscape analyses using thematic maps produced from the previously discussed endeavors suggested that terrestrial habitat in the Ray Roberts Lake area became more fragmented and complex in shape. Habitat patches became smaller but more numerous. Forested areas were most effected and conservation efforts should focus on management strategies that promote vegetation succession and forest maturation. Remotely sensed SPOT data were successfully used to predict tree basal area. There were no significant relationships found with other in situ measures or between MSS data and any vegetation measures. Remote sensing provided information suitable for large scale projects concerning landscape-level ecological issues. Rectification and classification accuracies were the ...
Date: December 1997
Creator: Smith, David P. (David Paul), 1956-

Descriptions, Life History and Case-Building Behavior of Culoptila cantha (Trichoptera: Glossosomatidae) in the Brazos River, Texas

Description: Larval, pupal and adult samples of Culoptila cantha, from a large riffle of the Brazos River in north-central Texas from January, 1995 to March, 1997, indicated a predominately trivoltine cycle during both years; the over-wintering generation spanned 6-7 months and warm-season generations spanned 2-3 months. Eggs, larvae of all instars, larval cases, case reconstruction progression and behavior, pupae, and adults are described.
Date: August 1997
Creator: Houghton, David Charles

The Use of Similarity Indicies to Assess the Spatial Differences of the Phytoplankton Communities in Lake Ray Roberts, Texas

Description: A study of the phytoplankton communities of Lake Ray Roberts was conducted at three sampling sites on two sampling dates during the summer of 1995, assessing both community structure and chlorophyll a concentrations. Eight similarity indices were then used to characterize and compare the communities of these sites. Both community similarity and chlorophyll a concentrations were evaluated using a minimum detectable difference equation to determine the amount of change that must occur in these parameters in order to be deemed statistically significant. The Bray-Curtis Index was shown to be the most adequate index evaluated, and was subsequently used in conjunction with bootstrap analysis to determine the similarity between the three sampling sites.
Date: August 1996
Creator: Banks, Kenneth E. (Kenneth Edward)

Evaluating Fish Impingement and Entrainment at the Comanche Peak Steam Electric Station

Description: This study was designed to determine if impingement and entrainment by cooling water intake at the Comanche Peak Steam Electric Station have an adverse impact upon the Squaw Creek Reservoir fish population. The yearly impingement of fish was estimated to be 262,994 of 14 species. The threadfin shad (Dorosoma petenense) accounted for 96% of this total. Entrainment of eggs and larvae for a five month period was estimated to be 15,989,987 and 42,448,794 respectively. Two fish population studies were performed on Squaw Creek Reservoir to help assess impact. It was determined that the losses due to impingement and entrainment have no adverse impact upon the fish population of Squaw Creek Reservoir.
Date: May 1996
Creator: Bauml, George A. (George Arthur)

Evaluation of a Constructed Wetland to Reduce Toxicity from Diazinon at the Pecan Creek Wastewater Treatment Plant, Denton, TX

Description: The City of Denton Pecan Creek Wastewater Treatment Facility has periodically failed effluent toxicity testing. A Toxicity Identification Evaluation has determined that Diazinon in the effluent is contributing to the observed toxicity. Chlorpyrifos is also implicated as a factor. The City of Denton constructed a half acre experimental wetland to remove Diazinon related toxicity. Results from spiking and microcosm experiments indicate that the wetland can reduce the Diazinon.
Date: May 1996
Creator: Baerenklau, Amy L. (Amy Lyn)

Biological and Toxicological Responses Resulting from Dechlorination of a Major Municipal Wastewater Treatment Plant Discharge to the Trinity River

Description: Federal regulations such as the Clean Water Act (P.L. 92-500), and its amendments, direct the Environment Protection Agency (EPA) to implement programs to control the releases of conventional pollutants and toxics into the waterways of the United States. The EPA began requiring treatment plants to conduct toxicity tests (biomonitoring) of their effluent discharges. To control toxicity caused by chlorination of wastewater discharges, the EPA also began requiring some treatment facilities to dechlorinate their wastewater before discharging. This research was funded by the EPA to document the changes that occurred in the Trinity River from the dechlorination of the effluent from Ft. Worth's Village Creek municipal wastewater treatment plant. The study occurred over a two year period beginning in August 1990. A wide variety of biological field assessments and toxicological assays were used to measure various responses. Seven river stations, covering approximately twenty river miles, and the treatment plant effluent were assessed. Two of the river stations were upstream from the treatment plant and used as reference sites. The remaining five river stations were downstream from the treatment plant, spread out over seventeen river miles. The study evaluated the impact of chlorination prior to dechlorination, which served as a baseline. Responses determined during dechlorination were compared to the baseline data. An overall improvement in species richness and diversity was seen at those river stations which had previously been adversely impacted by chlorine. Aquatic toxicity tests, such as those required to be used by dischargers, were conducted during this study. Periodic toxicity was observed with these tests in the effluent and river samples after dechlorination was initiated. Those tests, along with in situ toxicity assays, proved to be good predictors of biological community responses.
Date: August 1995
Creator: Guinn, Richard J. (Richard Joe)

A Two Semester Life Science Syllabus for Use in Texas Public Schools with Seventh Grade Students

Description: The problem of using a state adopted textbook written to apply to a large body of students with varying interests and needs was overcome by using a detailed syllabus that arranged course content in a meaningful sequence that appealed to student interest. The outlined syllabus prepared a two semester life science curriculum to be used by the teacher to guide lesson planning. Both semesters were divided into three units each. Materials included in the syllabus were given to actual student groups in real classroom settings. Since hands on learning was an important part of classroom instruction, two laboratory sections were included in the appendices to be used with the syllabus.
Date: May 1995
Creator: Edwards, Gail G. (Gail Graham)