13 resultados para race relations in the United States
em Aquatic Commons
Resumo:
Extensive losses of coastal wetlands in the United States caused by sea-level rise, land subsidence, erosion, and coastal development have increased hterest in the creation of salt marshes within estuaries. Smooth cordgrass Spartina altemiflora is the species utilized most for salt marsh creation and restoration throughout the Atlantic and Gulf coasts of the U.S., while S. foliosa and Salicomia virginica are often used in California. Salt marshes have many valuable functions such as protecting shorelines from erosion, stabilizing deposits of dredged material, dampening flood effects, trapping water-born sediments, serving as nutrient reservoirs, acting as tertiary water treatment systems to rid coastal waters of contaminants, serving as nurseries for many juvenile fish and shellfish species, and serving as habitat for various wildlife species (Kusler and Kentula 1989). The establishment of vegetation in itself is generally sufficient to provide the functions of erosion control, substrate stabilization, and sediment trapping. The development of other salt marsh functions, however, is more difficult to assess. For example, natural estuarine salt marshes support a wide variety of fish and shellfish, and the abundance of coastal marshes has been correlated with fisheries landings (Turner 1977, Boesch and Turner 1984). Marshes function for aquatic species by providing breeding areas, refuges from predation, and rich feeding grounds (Zimmerman and Minello 1984, Boesch and Turner 1984, Kneib 1984, 1987, Minello and Zimmerman 1991). However, the relative value of created marshes versus that of natural marshes for estuarine animals has been questioned (Carnmen 1976, Race and Christie 1982, Broome 1989, Pacific Estuarine Research Laboratory 1990, LaSalle et al. 1991, Minello and Zimmerman 1992, Zedler 1993). Restoration of all salt marsh functions is necessary to prevent habitat creation and restoration activities from having a negative impact on coastal ecosystems.
Resumo:
While researchers have evaluated the potential of native insect herbivores to manage nonindigenous aquatic plant species such as Eurasian watermilfoil ( Myriophyllum spicatum L.), the practical matters of regulatory compliance and implementation have been neglected. A panel of aquatic nuisance species program managers from three state natural resource management agencies (Minnesota, Vermont and Washington) discussed their regulatory and policy concerns. In addition, one ecological consultant attempting to market one of the native insects to manage Eurasian watermilfoil added his perspective on the special challenges of distributing a native biological control agent for management of Eurasian watermilfoil.
Resumo:
Executive Summary: Observations show that warming of the climate is unequivocal. The global warming observed over the past 50 years is due primarily to human-induced emissions of heat-trapping gases. These emissions come mainly from the burning of fossil fuels (coal, oil, and gas), with important contributions from the clearing of forests, agricultural practices, and other activities. Warming over this century is projected to be considerably greater than over the last century. The global average temperature since 1900 has risen by about 1.5ºF. By 2100, it is projected to rise another 2 to 11.5ºF. The U.S. average temperature has risen by a comparable amount and is very likely to rise more than the global average over this century, with some variation from place to place. Several factors will determine future temperature increases. Increases at the lower end of this range are more likely if global heat-trapping gas emissions are cut substantially. If emissions continue to rise at or near current rates, temperature increases are more likely to be near the upper end of the range. Volcanic eruptions or other natural variations could temporarily counteract some of the human-induced warming, slowing the rise in global temperature, but these effects would only last a few years. Reducing emissions of carbon dioxide would lessen warming over this century and beyond. Sizable early cuts in emissions would significantly reduce the pace and the overall amount of climate change. Earlier cuts in emissions would have a greater effect in reducing climate change than comparable reductions made later. In addition, reducing emissions of some shorter-lived heat-trapping gases, such as methane, and some types of particles, such as soot, would begin to reduce warming within weeks to decades. Climate-related changes have already been observed globally and in the United States. These include increases in air and water temperatures, reduced frost days, increased frequency and intensity of heavy downpours, a rise in sea level, and reduced snow cover, glaciers, permafrost, and sea ice. A longer ice-free period on lakes and rivers, lengthening of the growing season, and increased water vapor in the atmosphere have also been observed. Over the past 30 years, temperatures have risen faster in winter than in any other season, with average winter temperatures in the Midwest and northern Great Plains increasing more than 7ºF. Some of the changes have been faster than previous assessments had suggested. These climate-related changes are expected to continue while new ones develop. Likely future changes for the United States and surrounding coastal waters include more intense hurricanes with related increases in wind, rain, and storm surges (but not necessarily an increase in the number of these storms that make landfall), as well as drier conditions in the Southwest and Caribbean. These changes will affect human health, water supply, agriculture, coastal areas, and many other aspects of society and the natural environment. This report synthesizes information from a wide variety of scientific assessments (see page 7) and recently published research to summarize what is known about the observed and projected consequences of climate change on the United States. It combines analysis of impacts on various sectors such as energy, water, and transportation at the national level with an assessment of key impacts on specific regions of the United States. For example, sea-level rise will increase risks of erosion, storm surge damage, and flooding for coastal communities, especially in the Southeast and parts of Alaska. Reduced snowpack and earlier snow melt will alter the timing and amount of water supplies, posing significant challenges for water resource management in the West. (PDF contains 196 pages)
Resumo:
In 1998, the National Marine Fisheries Service (NMFS) began a series of marine angler expenditure surveys in the coastal regions of the United States (U.S.) to evaluate marine recreational fishing expenditures and the financial impacts of these expenditures in each region and the U.S. as a whole. In this report, we use the previously estimated expenditure estimates to assess the total financial impact of anglers’ saltwater expenditures. Estimates are provided for sales, income, employment, and tax impacts for each coastal state in the U.S. Aggregate estimates are also provided for the entire U.S., excluding Alaska, Hawaii, and Texas. Direct, indirect, and induced effects associated with resident and non-resident angler expenditures were estimated using a regional input-output modeling system called IMPLAN Pro. Nationwide, recreational saltwater fishing generated over $30.5 billion in sales in 2000, nearly $12.0 billion in income, and supported nearly 350,000 jobs. Approximately 89 cents of every dollar spent by saltwater anglers was estimated to remain within the U.S. economy. At the state level, many of the goods anglers purchased were imports, and, as such, as little as 44 cents of every dollar stayed in Rhode Island and as much as 80 cents of every dollar stayed in Georgia. In the Northeast, the highest impacts were generated in New Jersey, even though recreational fishing expenditures in Massachusetts and Maryland were considerably higher. In the Southeast, the highest impacts were generated in Florida, and on the Pacific Coast, the highest impacts were generated in California. Expenditures on boat maintenance/expenses generated more impacts than any other expenditure category in the U.S. Expenditures on rods and reels was the single most important expense category in terms of generating impacts in most of the Northeast states. Expenditures on boat expenses generated the highest in most Southeast states, and expenditures for boat accessories produced the highest impacts in most Pacific Coast states.(PDF file contains 184 pages.)
Resumo:
Over a decade ago, in August 1977, the First Marine Mammal Stranding Workshop was convened in Athens, Georgia. That workshop, organized by j.R. Geraci and D.J. St. Aubin, not only considered biology and pathology of stranded marine mammals, but it also served as a springboard for the formation of regional marine mammal stranding networks in the United States. The ramifications have been extremely important to the field of marine mammalogy since, for some species, examination or rehabilitation of stranded specimens serves as virtually the only source of information on distribution, anatomy, physiology, reproduction, and pathology. The First Marine Mammal Stranding Workshop led to increased awareness of the marine mammals themselves, as well as the logistic and legal factors associated with effective handling of the animals. A number of individuals indicated that they felt that a Second Marine Mammal Stranding Workshop held prior to the Seventh Biennial Conference on the Biology of Marine Mammals (Miami, Florida; December 1987) would be both timely and productive. Accordingly, we organized the workshop and scheduled it to occur on 3-5 December. Our goals for the workshop were several, including 1) providing descriptions of some research, especially new techniques, regarding stranded marine mammals; 2) providing a forum where scientists could interact and possibly initiate cooperative research activities; 3) presenting information regarding procedures used effectively to handle stranded animals; 4) assessing ways to standardize data and specimen collection, archiving, and retrieval; and 5) providing a forum for assessing accomplishments and status of regional stranding networks to date, as well as for making recommendations regarding future activities of the networks. Nearly 100 individuals representing Federal and State governments, academic institutions, the oceanarium industry, consulting groups, conservation organizations, and the private sector attended the workshop (see Workshop Participants, this volume). (PDF file contains 166 pages.)
Resumo:
Oyster landings in the United States and Canada have been based mainly on three species, the native eastern oyster, Crassostrea virginica, native Olympia oyster, Ostreola conchaphila, and introduced Pacific oyster, C. gigas. Landings reached their peak of around 27 million bushels/year in the late 1800's and early 1900's when eastern oysters were a common food throughout the east coast and Midwest. Thousands of people were involved in harvesting them with tongs and dredges and in shucking, canning, packing, and transporting them. Since about 1906, when the United States passed some pure food laws, production has declined. The causes have been lack of demand, siltation of beds, removal of cultch for oyster larvae while harvesting oysters, pollution of market beds, and oyster diseases. Production currently is about 5.6 million bushels/year.
Resumo:
This paper reviews and analyzes the major factors constraining the development of salmon culture in the United States. A brief review of economic factors in the seafood sector contributing to the industry's recent growth is offered, and the present status of the major producing regions is summarized. The major constraints, which include marketing problems, policy and regulatory constraints, production costs, disease, financiing, and environmental uncertainty, are discussed, followed by recommendations for improving the industry's development.
Resumo:
Seagrass ecosystems are protected under the federal "no-net-loss" policy for wetlands and form one of the most productive plant communities on the planet, performing important ecological functions. Seagrass beds have been recognized as a valuable resource critical to the health and function of coastal waters. Greater awareness and public education, however, is essential for conservation of this resource. Tremendous losses of this habitat have occurred as a result of development within the coastal zone. Disturbances usually kill seagrasses rapidly, and recovery is often comparatively slow. Mitigation to compensate for destruction of existing habitat usually follows when the agent of loss and responsible party are known. Compensation assumes that ecosystems can be made to order and, in essence, trades existing functional habitat for the promise of replacement habitat. While ~lant ingse agrass is not technically complex, there is no easy way to meet the goal of maintaining or increasing seagrass acreage. Rather, the entire process of planning, planting and monitoring requires attention to detail and does not lend itself to oversimplification.
Resumo:
We describe a 2.5-degree gridpoint atmospheric hydrology/climatology of precipitable water, precipitation, atmospheric moisture convergence, and a residual evaporation or evapotranspiration for the coterminous United States. We also describe a large-scale surface hydrology/climatology of a residual soil moisture, streamflow divergence, or runoff, as well as precipitation and evaporation. Annual and seasonal means and interrelationships among various components of the hydrologic cycles are discussed.