Louisianas small streams provide critical habitat for diverse ecologically and economically important fish species. However, the relationship between these fish assemblages and habitat variables remains poorly understood. The role of anthropogenic alteration of dendritic stream connectivity is of specific interest and has been shown to significantly influence stream ecology. This study explored the interaction among watershed characteristics, stream connectivity, stream physico-chemistry, and fish assemblages in little-studied Red River basin of central Louisiana as well as how reservoir littoral zones compared to streams, both in terms of fish assemblage and habitat. Fish and habitat were sampled in 21 headwater streams, half of which flowed directly into a reservoir, and in four reservoir littoral zone sites. Multivariate analyses indicated that level of dendritic connectivity did not explain a significant amount variation in stream fish assemblages. Fish assemblage composition and its relationship to common environmental gradients were similar in in all streams regardless of connectivity. Additionally, the assemblage and habitat of the reservoir littoral zone was comparable to that found in streams indicating that reservoirs were not serving as deleterious barriers to stream fish assemblages. However, individual species modeling revealed greater abundance of three species in streams with unaltered connectivity. These results do not parallel trends observed in other examinations of altered dendritic connectivity, however, they are concurrent with studies of coastal plain fishes response to other disturbances. Understanding the magnitude and structure of response to disturbance is critical for preserving aquatic ecosystems and focusing conservation efforts. Even systems such as the Red River Basin, which evidence strong resilience to human disturbance, warrant closer inspection before heedless system alteration continues.

The future of Louisianas coastal cypress-tupelo forests is threatened by prolonged or permanent flooding during the growing season. Permanent inundation prevents baldcypress seedlings from becoming established. The upper limit of submergence with respect to adequate planted baldcypress seedling performance has not been effectively tested under actual field conditions. Similarly, an effective method for determining a sites regeneration potential based on present vegetation attributes has not been developed. To test first-year performance of planted baldcypress seedlings under varying levels of submergence, I planted 900 of both 1-0 and 2-0 age-class bare-root seedlings across 12 different sites covering a range of hydrologic conditions and monitored their performance over the 2014 growing season. Water levels were continuously monitored for each individual seedling, and survival and height growth were documented. Due to their taller starting heights, 2-0 seedlings were submerged, on average, less often (1.4 days) than 1-0 seedlings (34.8 days). Survival was high across sites for both age classes (79% for 1-0 and 89% for 2-0). Survival of 1-0 seedlings decreased to only 9% following more than 90 cumulative days of submergence. Height growth across sites was greater for 1-0 seedlings (0.29 m) than 2-0 seedlings (0.13 m). Height growth of 1-0 seedlings decreased significantly following more than 30 cumulative days of submergence. To relate present vegetation attributes to baldcypress regeneration potential, I sampled the vegetation on all 12 sites in addition to using vegetation and hydrology data from five sites monitored by the Coastwide Reference Monitoring System (CRMS). Sites were separated into three categories based on how their hydrologic regime related to baldcypress regeneration potential. Sites with potential for natural regeneration were indicated by a species-diverse overstory and a high midstory stem density. Sites with only artificial regeneration potential were indicated by an overstory layer consisting almost exclusively of cypress-tupelo and a dense midstory layer with a high percentage of stems rooted on elevated structures. Sites with neither natural nor artificial regeneration potential were indicated by an overstory layer consisting almost exclusively of cypress-tupelo and a sparse midstory layer with a high percentage of stems rooted on elevated structures.

Multiple wetland restoration and enhancement techniques are used in Louisiana to combat land loss and provide habitat for waterbirds. We investigated the avian response to three wetland restoration techniques in the Lower Mississippi Birds Foot Delta to determine if the different habitat types resulted in differences in the value of edge habitat. Species richness, guild richness, total bird density, bird density by foraging guild, and bird abundance relative to distance from the marsh edge was compared among (i) crevasse splays, a type of sediment diversion which allow the river to build new wetlands, (ii), beneficial use of dredged material marshes, where heavy equipment to create new wetlands from sediments dredged from navigation channels, (iii) marsh terraces, where lighter equipment is used to create strips of edge habitat from sediments dredged from the restoration site, (iv) old edge marshes, representing pre-restoration conditions at degrading marshes, and (v) open water sites. Seasonal bird counts and vegetation surveys were conducted from March 2013 to October 2014 at plots within the Pass a Loutre State Wildlife Management Area and Delta National Wildlife Refuge in Plaquemines Parish, Louisiana, USA. We found bird abundance and diversity differs among the five habitat types during some times of the year, with habitat type and season often having a significant affect on the composition of the avian community. There was a significant relationship between habitat types and environmental factors (p=0.002), and a significant relationship between foraging guilds and environmental factors (p=0.002). Habitat type functions as a useful predictor of guild richness, but alone is not a perfect substitute for environmental variables when identifying the source of all variation in avian community composition. All habitat types studied provided habitat for birds, but were not utilized by all species or foraging guilds equally. We found that old edge marshes supported similar species richness as restored marshes during summer and winter (p<0.05) and open water supported the highest bird density in winter and spring (p<0.05). Any marsh habitat type, however, can be expected to support greater guild and species richness than open water areas during all seasons, but not greater bird density.

published_or_final_version / abstract / toc / China Area Studies / Master / Master of Arts

Managing for the long-term survival of a species requires an understanding of its population genetics. The desert tortoise, Gopherus agassizii, inhabits the Mojave and Sonoran deserts of North America. Desert tortoises face many threats to their continued survival, including habitat loss and fragmentation. I used mitochondrial and microsatellite DNA markers to examine genetic structure within and among populations of desert tortoises. I found that both the Mojave and Sonoran populations of desert tortoise exhibit similar patterns of population genetic structure. Gene flow among localities within each region is part of the evolutionary history of the desert tortoise and dispersal events probably play an important role in the long-term maintenance of populations. Movement barriers caused by anthropogenic landscape changes have the potential to effect desert tortoise population viability. Understanding the historical connectivity between and within the Mojave and Sonoran populations of desert tortoises will help facilitate the conservation of this species.

Published in cooperation with Arizona Water Commission and Office of Arid Lands Studies, University of Arizona. / Introduction: In many communities, irrigated agricultural areas exist within a few miles of the wastewater treatment plant of a large municipality. At such locations a dual transfer of water may be effected, in which the treated wastewater would be used for irrigation and the high quality irrigation water supply would in turn be shifted to the municipal system for domestic use. An investigation of the technical, economic, and legal aspects of such an exchange system has been completed recently, with the Tucson region as a case study. The research was done at the University of Arizona under an allotment grant from the Office of Water Resources Research, U.S. Department of the Interior.

Published in cooperation with Arizona Water Commission and Office of Arid Lands Studies, University of Arizona. / INTRODUCTION: Arid lands will undoubtedly experience increased energy stresses in the near future because of increasing internal populations and external energy appetites. Many arid lands are underlain by vast quantities of energy fuels, but geothermal energy is one of the few environmentally acceptable energy alternatives for arid regions based on criteria of water consumption, efficiency of energy production and pollution characteristics. This report summarizes the published findings of the authors' search of existing data related to Arizona geothermal resources and of geological investigations undertaken by them to provide a comprehensive guide for exploration and to suggest further studies.

Published in cooperation with Arizona Water Commission and Office of Arid Lands Studies, University of Arizona.

Project Completion Report, OWRT Project No. A-054-ARIZ / Agreement No. 14-31-0001-5003 / Project Dates: July 1974 - August 1975 / Acknowledgement: The work upon which this report is based was supported by funds provided by the United States Department of the Interior, Office of Water Research and Technology, as authorized by the Water Resources Research Act of 1964. / Conventional geothermal water resources of Arizona are apparently limited to an east-west trending belt about 100 miles wide within the Basin-Range province of Arizona and closely following the Gila River. Hot-dry rock and magma-tap types of geothermal energy may also be present within this zone as well as outside it as for example, in the Flagstaff area. Numerous wells and springs with temperatures greater than 32 degrees C are found within the 100 mile-wide zone, and commonly their locations are coincident with linear features described by ERTS photographs. Application of geochemical geothermometers to these waters yields predicted reservoir temperatures up to 150 degrees C, although Tellier (1973) reports values up to 300 degrees C for waters from this region. Well logs, core, and outcroppings of basin fill deposits in Safford Basin suggest that thermal waters are contained in coarse sand and conglomeratic basin fill reservoirs and possibly in lava flows and tuff deposits under the sediments which fill the basin. Shallow lacustrine deposits of evaporites and clays probably function as cap rocks in this area preventing mixing of warm deeper waters with cooler surface waters. Igneous rocks of very recent age are consistently found within the zone containing the thermal waters. These bodies represent the most probable source of thermal energy, although in Safford Basin heat may originate from exothermic hydration reactions of anhydrite in lacustrine evaporite deposits.

No description available.