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21.
Abstract: Recreational angling is a popular leisure activity, the quality of which is greatly dependent on fish abundance and well‐functioning aquatic ecosystems. Aquatic protected areas (APAs) are used to help maintain and even restore aquatic systems and their associated biota, including fish species that are popular with recreational anglers. Paradoxically, the use of APAs has been a source of much contention and conflict between members of the recreational angling community and those interested in or mandated to protect aquatic resources on the basis of the interests of multiple stakeholder groups. The angling community is concerned about the loss of fishing opportunities and effectiveness of APAs. Although it is still unclear whether establishment of APAs alone can effectively protect aquatic resources, actively including the recreational angling community in the design, implementation, and management of APAs will help ensure the values of this rather substantial user group are incorporated into aquatic conservation strategies. Conversely, the probability of increasing the sustainability of recreational angling and related economies will be greatest if recreational angler groups remain open minded to both short‐term and long‐term goals of fisheries conservation strategies, including the use of APAs.  相似文献   
22.
Abstract:  Funding of ecological research and monitoring of Neotropical migratory birds on their overwintering grounds has benefited both migratory and permanent-resident species. Using examples from our work in Puerto Rico and the Dominican Republic, we demonstrate that ecological research of overwintering migrants often provides information about the ecology and demography of little-known tropical resident birds. Critically important long-term monitoring in Puerto Rico with a focus on winter residents has provided information on the relationships between annual rainfall and fluctuations in resident bird populations and survival rates. It also has alerted local biologists to declines in resident bird populations, including a decline apparently driven by the entry of a brood parasite. But migrant-focused research may also have had an underappreciated effect on the development of conservation capacity and conservation efforts in host countries. Investments in research on Neotropical migrants overwintering on Hispaniola have resulted in a huge increase in field training of students and wildlife professionals, promoted conservation awareness at local and national levels, played an important role in the growth and professionalization of key environmental organizations, spawned a growing ecotourism industry for bird-watching, and driven national park management planning and conservation efforts for all bird species. We encourage funding organizations and agencies to consider the broader impacts of funding migratory-bird research and monitoring efforts, and we encourage researchers in the tropics to use protocols that provide the most information about all the birds that use the study areas involved and to be aware of important opportunities that they may have to build capacity in host countries.  相似文献   
23.
Aquatic species are threatened by climate change but have received comparatively less attention than terrestrial species. We gleaned key strategies for scientists and managers seeking to address climate change in aquatic conservation planning from the literature and existing knowledge. We address 3 categories of conservation effort that rely on scientific analysis and have particular application under the U.S. Endangered Species Act (ESA): assessment of overall risk to a species; long‐term recovery planning; and evaluation of effects of specific actions or perturbations. Fewer data are available for aquatic species to support these analyses, and climate effects on aquatic systems are poorly characterized. Thus, we recommend scientists conducting analyses supporting ESA decisions develop a conceptual model that links climate, habitat, ecosystem, and species response to changing conditions and use this model to organize analyses and future research. We recommend that current climate conditions are not appropriate for projections used in ESA analyses and that long‐term projections of climate‐change effects provide temporal context as a species‐wide assessment provides spatial context. In these projections, climate change should not be discounted solely because the magnitude of projected change at a particular time is uncertain when directionality of climate change is clear. Identifying likely future habitat at the species scale will indicate key refuges and potential range shifts. However, the risks and benefits associated with errors in modeling future habitat are not equivalent. The ESA offers mechanisms for increasing the overall resilience and resistance of species to climate changes, including establishing recovery goals requiring increased genetic and phenotypic diversity, specifying critical habitat in areas not currently occupied but likely to become important, and using adaptive management. Incorporación de las Ciencias Climáticas en las Aplicaciones del Acta Estadunidense de Especies en Peligro para Especies Acuáticas  相似文献   
24.
Pollution due to persistent pesticides is not a regional but a global problem. Organochlorine pesticides are persistent chemicals, stored and accumulated in the tissues of a wide variety of invertebrates and vertebrates including marine species. In the present study the organochlorine residues HCHs, DDTs and PCBs were measured in different trophic groups of birds (scavengers, inland piscivores, coastal piscivores, insectivores, granivores and omnivores) collected from Tamil Nadu Coast, India. The residue accumulation as a function of sex did not depict distinct variation. However, females had lower residue levels than males in terms of their mean weight and feeding habits. A continuous monitoring programme is recommended to establish the studied organisms as indicator species.  相似文献   
25.
Nickel pollution is a serious environmental problem, and its effects may provoke alterations in the ecosystem and in organism of animals and humans. Dermatitis, eczema, and asthma are some illnesses caused by Ni2+ poisoning. In this work, fish fed either Ni2+-enriched pellets or commercial pellets were studied. The amount of Ni2+ in fish were measurements by adsorptive stripping voltammetry (AdSV) with dimethylglyoxime as a complexing agent. The analysis of Ni2+ in fish by AdSV established that its accumulation occurs principally in viscera (670.86 ± 5.82 µg g?1), in the head (697.12 ± 2.77 µg g?1) and in the muscle (405.82 ± 3.26 µg g?1), both after 12 months of experiments. Ni2+ adsorbs preferentially in organs such as the stomach, the intestine, and the kidneys and acts in the central nervous system as well. Tilapia growth and mass were significantly affected by Ni2+ poisoning. From statistical analysis, observed that the results for lengths, weights and metal concentration were different for each sampling at significance level of p < 0.05. The Ni2+ concentration in tilapia was enough to cause the death of tilapias; however, it did not occur because the presence of Zn2+ might act as protective agent of heavy metals.  相似文献   
26.
/ An exhaustive search of the literature for foot and vehicle traffic impacts on vegetation has yielded more than 400 citations, two thirds of which held sufficient detail to be usefully distilled into a personal-computer data base. A total of 1444 individual observations involving 737 species that were trampled are included. Compromises were made in the depth of entry detail and to allow comparability among data. Inconsistent, generally short-term, experimental practices disallowed formal statistical analyses. Within those constraints, graminoids emerged with the highest mean resistance and resilience among life-forms. Climbers and cactoids ranked lowest in these categories. The herbaceous, typically broader-leaved (forb) life-form appeared most likely to suffer immediate losses. Shrubs and trees had the longest-lasting decreases in diversity following traffic impact. All life-forms had sensitive species. The greatest general species and individual plant losses take place in the first few passes by feet, wheels, or tracks. Plant and soil damage increases with the amount of weight and power applied. Greater soil moisture and/or deeper overstory shading magnify those impacts. Additional precepts may become apparent to data-base users through increased ease in making comparisons.KEY WORDS: Vegetation; Trampling; Vehicles; Traffic; Resistance; Resilience; Data base  相似文献   
27.
Researchers have noted that upward influence tactics are often used in varying patterns and combinations (e.g. Yukl and Falbe, 1990). This study investigated whether influence strategies representing hard, soft, or rational approaches to influence behavior would emerge in relation to upward influence tactics of assertiveness, rationality, coalition, upward appeal, ingratiation, and exchange. Hypotheses were offered concerning the relations of selected demographic, individual difference, relational, and opportunity factors to these strategies. The 225 participants were full-time employees of a national non-profit organization. Second-order factor analysis provided some support for the dimensionalization of upward influence tactics as representing hard, soft, and rational strategies. Each strategy was related to a unique set of predictors. The results suggest a higher level of complexity for influence strategies than previously expected. The implications of this study, as well as fruitful areas for future research, are discussed. © 1997 John Wiley & Sons, Ltd.  相似文献   
28.
Public agencies sometimes seek outside guidance when capacity to achieve their mission is limited. Through a cooperative agreement and collaborations with the U.S. National Park Service (NPS), we developed recommendations for a conservation program for migratory species. Although NPS manages ~36 million hectares of land and water in 401 units, there is no centralized program to conserve wild animals reliant on NPS units that also migrate hundreds to thousands of kilometers beyond parks. Migrations are imperiled by habitat destruction, unsustainable harvest, climate change, and other impediments. A successful program to counter these challenges requires public support, national and international outreach, and flourishing migrant populations. We recommended two initial steps. First, in the short term, launch or build on a suite of projects for high‐profile migratory species that can serve as proof to demonstrate the centrality of NPS units to conservation at different scales. Second, over the longer term, build new capacity to conserve migratory species. Capacity building will entail increasing the limited knowledge among park staff about how and where species or populations migrate, conditions that enable migration, and identifying species’ needs and resolving them both within and beyond parks. Building capacity will also require ensuring that park superintendents and staff at all levels support conservation beyond statutory borders. Until additional diverse stakeholders and a broader American public realize what can be lost and do more to protect it and engage more with land management agencies to implement actions that facilitate conservation, long distance migrations are increasingly likely to become phenomena of the past. Optimismo y Retos para la Conservación Científicamente Basada de Especies Migratorias Dentro y Fuera de Parques Nacionales de E.U.A.  相似文献   
29.
As the discipline of conservation biology evolves and practitioners grow increasingly concerned about how to put results into achievable conservation, it is still unclear the extent to which science drives conservation outcomes, especially across rural landscapes. We addressed this issue by examining the role of science in the protection of a biological corridor. Our focus is on a North American endemic mammal reliant on long distance migration as an adaptive strategy, the pronghorn (Antilocapra americana) of the southern Greater Yellowstone Ecosystem. The role of science in realizing policy change, while critical as a first step, was surprisingly small relative to the role of other human dimensions. In a case study, we strategically addressed a variety of conservation needs beyond science, first by building a partnership between government and private interests and then by enhancing interest in migratory phenomena across a landscape with divergent political ideologies and economic bases. By developing awareness and even people's pride in the concept of corridor conservation, we achieved local, state, and federal acceptance for protection of a 70 km long, 2 km wide pathway for the longest terrestrial migrant in the contiguous United States. Key steps included conducting and publishing research that defined the migration corridor; fostering a variety of media coverage at local, regional, and national levels; conducting public outreach through stakeholder workshops, meetings, and presentations; and meeting with and gaining the support of elected officials. All these contributed to the eventual policy change that created the first federally protected migration corridor in the United States, which in turn stimulated additional conservation actions. On the basis of our experience, we believe conservation scientists can and should step beyond traditional research roles to assist with on‐the‐ground conservation by engaging in aspects of conservation that involve local communities and public policy. Ir Más Allá de la Ciencia para Proteger un Corredor Migratorio de Mamíferos  相似文献   
30.
Wildlife crossing structures are one solution to mitigating the fragmentation of wildlife populations caused by roads, but their effectiveness in providing connectivity has only been superficially evaluated. Hundreds of grizzly (Ursus arctos) and black bear (Ursus americanus) passages through under and overpasses have been recorded in Banff National Park, Alberta, Canada. However, the ability of crossing structures to allow individual and population‐level movements across road networks remains unknown. In April 2006, we initiated a 3‐year investigation into whether crossing structures provide demographic connectivity for grizzly and black bears in Banff National Park. We collected hair with multiple noninvasive methods to obtain genetic samples from grizzly and black bears around the Bow Valley. Our objectives were to determine the number of male and female grizzly and black bears that use crossing structures; examine spatial and temporal patterns of crossings; and estimate the proportions of grizzly and black bear populations in the Bow Valley that use crossing structures. Fifteen grizzly (7 female, 8 male) and 17 black bears (8 female, 9 male) used wildlife crossing structures. The number of individuals detected at wildlife crossing structures was highly correlated with the number of passages in space and time. Grizzly bears used open crossing structures (e.g., overpasses) more often than constricted crossings (e.g., culverts). Peak use of crossing structures for both bear species occurred in July, when high rates of foraging activity coincide with mating season. We compared the number of bears that used crossings with estimates of population abundance from a related study and determined that substantial percentages of grizzly (15.0% in 2006, 19.8% in 2008) and black bear (17.6% in 2006, 11.0% in 2008) populations used crossing structures. On the basis of our results, we concluded wildlife crossing structures provide demographic connectivity for bear populations in Banff National Park. Conectividad Demográfica para Poblaciones de Úrsidos en Estructuras para Cruce de Vida Silvestre en el Parque Nacional Banff  相似文献   
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