927 resultados para Aquatic ecotoxicity
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Four methods to control the smooth cordgrass Spartina (Spartina alterniflora) and the footwear worn by treatment personnelat several sites in Willapa Bay, Washington were evaluatedto determine the non-target impacts to eelgrass (Zostera japonica). Clone-sized infestations of Spartina were treated bymowing or a single hand-spray application of Rodeo® formulatedat 480 g L-1acid equivalence (ae) of the isopropylaminesalt of glyphosate (Monsanto Agricultural Co., St. Louis, MO;currently Dow AgroSciences, Indianapolis, IN) with the nonionic surfactant LI 700® (2% v/v) or a combination of mowing and hand spraying. An aerial application of Rodeo® with X-77 Spreader® (0.13% v/v) to a 2-ha meadow was also investigated. Monitoring consisted of measuring eelgrass shoot densities and percent cover pre-treatment and 1-yr post-treatment. Impacts to eelgrass adjacent to treated clones were determined 1 m from the clones and compared to a control 5-m away. Impacts from footwear were assessed at 5 equidistant intervals along a 10-m transect on mudflat and an untreated control transect at each of the three clone treatment sites. Impacts from the aerial application were determined by comparing shoot densities and percent cover 1, 3 and 10 m from the edge of the treated Spartina meadow to that at comparable distances from an untreated meadow. Methods utilized to control Spartina clones did not impact surrounding eelgrass at two of three sites. Decreases in shoot densities observed at the third site were consistent across treatments. Most impacts to eelgrass from the footwear worn by treatment personnel were negligible and those that were significant were limited to soft mud substrate. The aerial application of the herbicide was associated with reductions in eelgrass (shoot density and percent cover) at two of the three sampling distances, but reductions on the control plot were greater. We conclude that the unchecked spread of Spartina is a far greater threat to the survival and health of eelgrass than that from any of the control measures we studied. The basis for evaluating control measures for Spartina should be efficacy and logistical constraints and not impacts to eelgrass. PDF is 7 pages.
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CONTENTS: An experience with group formation in Jabarrah, West Bengal, by Amar Prasad, Virendra Singh, Binay Sahay and Gautum Dutta. Aquaculture self-help groups in rural West Bengal, by Satyendra Tripathi, Graham Haylor and William Savage in consultation with Jagdish Gangwar, Virendra Singh, Gautam Dutta and Prabhat Pathak. Lessons learned for Fulwar Toli from an exposure visit to Jabarrah Bhim Nayak and Rubu Mukherjee. Livelihood intervention by Fish Farmers Development Agency: a success story from Mayurbhanj, Orissa, by G.B. Parida. Understanding of assets-based livelihoods through participatory rural appraisal to eliminate hunger, by Binay Sahay. Poverty ranking tools in PRA: experiences of EIRFP in addressing vulnerability, by Binay Sahay.
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CONTENTS: Creating understanding and ownership of collaborative research results through ‘learning by doing,’ by Robert Arthur and Caroline Garaway. Fish culture, farming, markets and promotion: an integrated, sustainable approach to aquaculture and rural development, by Pen Rotha and Brendan Boucher. Fisheries policy reform impact assessment in Cambodia: understanding policy and poor people, by Philip Townsley and Sem Viryak. “Shrimp Hero” Phan The Phuong, by Ngo Minh Khoi. Coral farming in Vietnam, by Nguyen Viet Vinh. The global fisheries market: can rural poor people benefit? Issues raised by STREAM Media Monitoring Reports, by Paul Bulcock.
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CONTENTS: BFAR moves on in Region 6, by Janice N. Tronco. Livelihoods initiatives in Sapian Bay, by Tee-Jay A. San Diego. Improving access to information through Barangay Learning Resource Centers, by Elizabeth M. Gonzales. The Philippines Fisheries Information System, by Agnes C. Solis. The contributions of planning activities in the participatory process, by Rommel P. Guarin. Inter-LGU alliance building: a key to sustaining the Integrated Fisheries and Aquatic Resource Management Council (IFARMC), by Josephine P. Savaris.
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Water chestnut (Trapa natans L.,sensu lato) is an annual, floating-leaved aquatic plant of temperate and tropical freshwater wetlands, rivers, lakes, ponds, and estuaries. Native to Eurasia and Africa, water chestnut has been widely gathered for its large nutritious seed since the Neolithic and is cultivated for food in Asia. Water chestnut is now a species of conservation concern in Europe and Russia. Introduced to the northeastern United States in the mid-1800s, the spread of water chestnut as a nuisance weed was apparently favored by cultural eutrophication. Water chestnut is considered a pest in the U.S. because it forms extensive, dense beds in lakes, rivers, and freshwater-tidal habitats.
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Two biotypes of hydrilla [Hydrilla verticillata(L.f.) Royle] occur in the United States, a dioecious type centered in the southeast and a monoecious type in the central Atlantic and northeastern states. Ecosystem managers need tools to distinguish the types as the ranges of each type expand and begin to overlap. A molecular tool using the randomly amplified polymorphic DNA (RAPD) procedure is available but its use is limited by a need for reference samples. We describe an alternative molecular tool which uses “universal primers” to sequence the trnL intron and trnL-F intergenic spacer of the chloroplast genome. This sequence yields three differences between the biotypes (two gaps and one single nucleotide polymorphism). A primer has been designed which ends in a gap that shows up only in the dioecious plant. A polymerase chain reaction (PCR) using this primer produces a product for the monoecious but not the dioecious plant.
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Dense, monospecific cattail (Typha spp.) stands are a problem in many prairie wetlands because they alter habitat structure and function, resulting in a decrease in use by wildlife species. Cheyenne Bottoms Wildlife Area, a Wetland of International Importance in central Kansas, has experienced a large increase in cattails and a subsequent decrease in migratory wetland bird use. As a consequence, intensive cattail management is practiced. We assessed the effectiveness of prescribed burning, discing following prescribed burning, and cattle grazing following prescribed burning at two stocking rates of 5 and 20 head per 11 ha in suppressing cattail, as well as the effects of these treatments on non-cattail vegetation.
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Waterhyacinth (Eichhornia crassipes(Mart.) Solms), is a serious problem in the Sacramento Delta. Two weevil species (Neochetina bruchi Hustache and N. eichhorniae Warner) have been introduced as biological control agents. The purpose of this study was to test the hypothesis that nitrogen (N) in the tissue of waterhyacinth was not sufficient to support weevil growth and reproduction. Because it grows better on plants with high N content and because it has a greater impact on the growth of high N plants, N. bruchi may be a more effective biological control agent in the Sacramento Delta.
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We conducted a field experiment between August 2001 and February 2002 in Kings Bay, FL, USA, designed to determine whether the amount of time allowed for wild celery (Vallisneria americana Michx) transplants to establish altered the effect of herbivorous manatees (Trichechus manatus L.)on their survival.
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CONTENTS: What do we need to learn about to understand how people live, by Kath Copley and William Savage. Taking steps to making livelihoods work, by Erwin L. Pador. Reflections on the India-Nepal Workshop, by Rubu Mukherjee and Nilkanth Pokhrel. Reflections on the role of livelihoods approaches and analysis in Lao PDR, by Phanthavong Vongsamphanh and Graham Haylor. After the Workshop on Livelihoods Approaches and Analysis, by Khin Maung Soe, Aye Aye Zaw, Nilar Kyawe and Myant Thar Htun. The relevance of livelihoods approaches in Yunnan, China, by Susan Li and William Savage
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CONTENTS: Pasoso project: local livelihoods and turtle conservation in a small island MPA in central Sulawesi, Indonesia, by Abigail Moore. Fisheries development in Lao PDR, by Khamphet Roger. Creating better fisher livelihoods through leasable fisheries, by Khin Maung Soe. The Jankar system for sustainable livelihoods: lessons from the EIRFP, by Binay Kumar Sahay. Alternative livelihoods for landlocked areas in BFAR Region 6, by Jacqueline T. Mamburam. Lessons learned and future replication from Trao reef locally managed marine reserve, by Than Thi Hien.
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CONTENTS: Young people taking bolder steps, by Josephine P. Savaris. Providing a venue for voices to be heard, by Elizabeth M. Gonzales and Josephine Savaris. Rehabilitation of Bundu Pond: STREAM’s Initiative and DoF’s Action, by Bhim Nayak and Ashish Kumar. Coastal resources utilization and conservation issues in Cox’s Bazar, Bangladesh, by M.K. Abu Hena, H. Sharifuzzaman, M.S. Aftabuddin and M.N. Haque. People, fish and reefs: a livelihoods learning curve, by Abigail Moore. Understanding the marine ornamental trade and its impact on the livelihoods of poor stakeholders in the Philippines, by Elizabeth M. Gonzales.