6 resultados para Wetlands

em DigitalCommons@University of Nebraska - Lincoln


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Wetland ecology is a relatively new field that developed from an initial interest in a few direct benefits that wetlands provide to society. Consequently, much early scientific work was stimulated by economic returns from specific wetland services, such as production of peat and provision of habitat for economically valuable wildlife (e.g., waterfowl and furbearers). Over time, societal interest in wetlands broadened, and these unique habitats are now valued for many additional services, including some that bear non market value. Common examples include carbon sequestration, flood reduction, water purification, and aesthetics. The increased recognition of the importance of wetlands has generated a diversity of job opportunities in wetland ecology and management. Despite the increased knowledge base and enhanced job market, I am not aware of any institutions that offer specialty degrees in this new discipline. Indeed, relatively few institutions offer specific wetland ecology classes, with Arnold G. van der Valk and a few of his peers at other universities being notable exceptions.

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Responding to a U.S. Federal court order to improve discharged wastewater quality, Augusta, Georgia initiated development of artificial wetlands in 1997 to treat effluents. Because of the proximity to Augusta Regional Airport at Bush Field, the U.S. Federal Aviation Administration expressed concern for potential increased hazard to aircraft posed by birds attracted to these wetlands. We commenced weekly low-level aerial surveys of habitats in the area beginning January, 1998. Over a one-year period, 49 surveys identified approximately 42,000 birds representing 52 species, including protected Wood Storks and Bald Eagles, using wetlands within 8 km of the airport. More birds were observed during the mid-winter and fall/spring migratory seasons (1,048 birds/survey; October - April) than during the breeding/post-breeding seasons (394 birds/survey; May - September). In winter, waterfowl dominated the avian assemblage (65% of all birds). During summer, wading birds were most abundant (56% of all birds). Habitat changes within the artificial wetlands produced fish kills and exposed mudflats, resulting in increased use by wading birds and shorebirds. No aquatic birds were implicated in 1998 bird strikes, and most birds involved could safely be placed within songbird categories. Airport incident reports further implicated songbirds. These findings suggested that efforts to decrease numbers of songbirds on the airport property must be included in the development of a wildlife hazard management plan. Seasonal differences in site use among species groups should also be considered in any such plan. Other wetlands within 8 km of the airport supported as many or more birds than the artificial wetlands. With proper management of the artificial wetlands, it should be possible to successfully displace waterfowl and wading birds to other wetlands further from the airport.

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Table of Contents: America’s Birds: In an Alarming State Snakes Alive! Title Sub Title East Coast Wetlands Are Disappearing Chief’s Corner: What We Do Now Extreme Makeover for Bird Sightings by Mike Carlo Taking Care of Our World War II Legacy by Lisa Matlock Whatever Happened to . . . . San Francisco Bay Wetland Restoration Projects Recalling the Battle of Long Island Sound by David Klinger Bold Approaches for Climate Change How Alligator River Refuge Is Planning and Adapting by Mike Bryant Rapid Climate Change Is Transforming the Arctic by David Payer Tracking Change on Wildlife Refuges by Kathy Granillo Where SLAMM Foretells a Wetter Future Reviving the Land – and the Air by Bob Ford and Pete Jerome Connecting the Conservation Landscape a New Priority by Mike Scott and Bob Adamcik Awards for Refuge System Palmyra Atoll Refuge Becomes Ramsar Site Not So Strategic Habitat Conservation: A True Story by David Viker Putting Food on Alaskan Tables by Andy Aderman

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Table of Contents: Rebuilding after Hurricane Ike, page 3 Texas and Louisiana refuges were severely damaged in mid-September. A Crane Species Rebounding, page 5 At a Mississippi refuge, the world’s longest-running crane reintroduction program is succeeding. Focus on. . . Refuge System Wetlands, pages 8-13 The Refuge System manages wetlands to enhance their value for migratory waterfowl and shorebirds, threatened and endangered species and a myriad of native fish, wildlife, and plants. Fluttering Close to Extinction, page 17. Antioch Dunes Refuge is out to save the Lange’s metalmark butterfly.

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As with many organisms across the globe, Cicindela nevadica lincolniana is threatened with extinction. Understanding ecological factors that contribute to extinction vulnerability and what methods aid in the recovery of those species is essential in developing successful conservation programs. Here we examine behavioral mechanisms for niche partitioning along with improving techniques for captive rearing protocol and increasing public awareness about the conservation of this local insect. Ovipositional selectivity was examined for Cicindela nevadica lincolniana, Cicindela circumpicta, Cicindela togata, Cicindela punctulata, and Cicindela fulgida. Models reflect that these species of co-occurring tiger beetles select different ranges of salinity in which to oviposit thereby reducing the potential for interspecific competition. In a second study, thermoregulatory niche partitioning was examined for the same complex of tiger beetle species. Time spent in the sun, on different substrates, and engaging in various behaviors associated with thermoregulation were significantly different during different parts of the day and between species. I continued along a previous line of study to develop a viable captive rearing program. So far fourteen adult Cicindela nevadica lincolniana have been successfully reared in captivity. Overwintering mortality has been determined as a key factor in the mortality of this species in captivity. Finally, I examined the potential for using the visual arts to promote the conservation of Cicindela nevadica lincolniana and associated saline wetlands. The results from surveys conducted at the exhibit suggest that art exhibits can have a strong positive impact on members of the community.

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The wetlands of south-central Nebraska’s Rainwater Basin region are considered of international importance as a habitat for millions of migratory birds, but are being endangered by agricultural practices. The Rainwater Basin extends across 17 counties and covers 4,000 square miles. The purpose of this study was to assemble baseline chemical data for several representative wetlands across the Rainwater Basin region, and determine the use of these chemical data for investigating groundwater recharge. Eight representative wetlands were chosen across the Rainwater Basin to monitor surface and groundwater chemistry. At each site, a shallow well and deep well were installed and sampled once in the summer of 2009 and again in the spring of 2010. Wetland surface water was sampled monthly from April, 2009 to May, 2010. Waters were analyzed for major ions, nutrients, pesticides and oxygen-18 and deuterium isotopes at the University of Nebraska Water Sciences Laboratory. Geochemical analysis of surface waters presents a range of temporal and spatial variations. Wetlands had variable water volumes, isotopic compositions, ion chemistries and agricultural contaminant levels throughout the year and, except for a few trends, theses variations cannot be predicted with certainty year-to-year or wetland-to-wetland. Isotopic compositions showed evaporation was a contributor to water loss, and thus, did impact water chemistry. Surface water nitrate concentrations ranged from <0.10 to 4.04 mg/L. The nitrate levels are much higher in the groundwater, ranging from <0.10 to 18.4 mg/L, and are of concern because they are found above the maximum contaminant level (MCL) of 10 mg/L. Atrazine concentrations in surface waters ranged from <0.05 to 10.3 ppb. Groundwater atrazine concentrations ranged from <0.05 to 0.28 ppb. The high atrazine concentrations in surface waters are of concern as they are above the MCL of 3 ppb, and the highest levels occur during the spring bird migration. Most sampled groundwaters had detectable tritium indicating a mix of modern (<5 to 10 years old) and submodern (older than 1950s) recharge. The groundwater also had differences in chemical and isotope composition, and in some cases, increased nitrate concentrations, between the two sampling periods. Modern groundwater tritium ages and changes in groundwater chemical and isotopic compositions may indicate connections with surface waters in the Rainwater Basin.