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11.
Abstract: Four potentially endangered species of rainforest fishes, Barbus cumingi, Barbus nigrofasciatus, Barbus titteya, and Rasbora vaterofloris, endemic to streams of southwestern Sri Lanka, were translocated in 1981 into a depauperate stream system in the central hills. By 1985 all four species had established self-perpetuating populations in these streams, and had extended their ranges into adjacent stream Barbus nigrofasciatus, a generalist, was one of the most abundant species in these stream It was widely distributed throughout the stream system and in the slower sections of the Mabaveli Ganga (=Mabaveli River), and occupied a wide range of macro- and microhabitat types. The other three species were more specialized in their habitat and diet, and were thus patchily distributed. The microhabitats occupied by B. cumingi, B. titteya, and R. vaterifloris resembled the specialized microhabitats they occupy in their native stream Presumably because of their specializations, these three species were not as abundant as B. nigrofasciatus. Overall, the biology and distribution of the four species will enable them to survive spatially small-scale environmental perturbations The results suggest that trans locations are a feasible means of conserving other endemic fishes of Sri Lanka threatened with extinction. However, such translocations must be carefully planned with consideration for the indigenous community as well as the ecological requirements and genetic integrity of the target species.  相似文献   
12.
Population Viability Analysis for an Endangered Plant   总被引:9,自引:0,他引:9  
Abstract: Demographic modeling is used to understand the population viability of Furbish's lousewort, Pedicularis furbishiae , a perennial plant species endemic to the St. John River Valley in northern Maine. Environment-specific summaries of demographic parameters (survivorship, growth, and fecundity) over four years, organized into stage-based projection matrices, provide predictions of future population dynamics given a deterministic extension of past conditions. Stochastic modeling, using (I) empirically observed variation in demographic parameters, and (2) estimated rates of natural catastrophes, leads to predictions of extinction probability.
P. furbishiae viability has varied widely over the study period Viable populations with finite rates of increase > 1 are found where cover is low, woody plants do not dominate, and disturbance does not occur. Rates of increase vary over time, suggesting that stochastic analyses would be realistic. Stochastic measures of population viability incorporating environmental variation suggest that early successional environments, especially wetter sites, can support viable populations in the absence of disturbance. However; observed rates of natural catastrophe dominate viability estimates of individual populations. Metapopulation dynamics feature extinction rates that are greater than recolonization rates, and may be affected by land use in the watershed Species management needs to consider a large-scale view of the riverine corridor.  相似文献   
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Graduate education programs in conservation science generally focus on disciplinary training and discipline‐specific research skills. However, nonacademic conservation professionals often require an additional suite of skills. This discrepancy between academic training and professional needs can make it difficult for graduate students to identify the skills and experiences that will best prepare them for the conservation job market. We analyzed job advertisements for conservation‐science positions and interviewed conservation professionals with experience hiring early‐career conservation scientists to determine what skills employers of conservation professionals seek; whether the relative importance of skills varies by job sector (government, nonprofit, and private); and how graduate students interested in careers in conservation science might signal competency in key skills to potential employers. In job advertisements, disciplinary, interpersonal, and project‐management skills were in the top 5 skills mentioned across all job sectors. Employers’ needs for additional skills, like program leadership, conflict resolution and negotiation, and technical and information technology skills, varied across sectors. Our interview results demonstrated that some skills are best signaled to employers via experiences obtained outside thesis or dissertation work. Our findings suggest that graduate students who wish to be competitive in the conservation job market can benefit by gaining skills identified as important to the job sector in which they hope to work and should not necessarily expect to be competent in these skills simply by completing their chosen degree path. Guía para el Estudiante de Grado de las Habilidades Necesarias para Carreras de Conservación Académicas  相似文献   
14.
Abstract: Competitive species interactions may contribute to population declines. Purportedly, Red‐bellied Woodpeckers (Melanerpes carolinus), a common species, and Red‐cockaded Woodpeckers (Picoides borealis), an endangered species, compete for roosting and nesting cavities in living pine trees. To determine whether behavioral interactions measured at the individual level manifest themselves at the population level, we conducted field experiments designed to test whether the presence of Red‐bellied Woodpeckers resulted in a decrease in fitness to Red‐cockaded Woodpeckers. As part of a 4‐year study examining the nature of interspecific interactions in two populations of Red‐cockaded Woodpeckers (one stable, the Apalachicola Ranger District; one declining, the Wakulla Ranger District) in the Apalachicola National Forest, Florida, we conducted a set of Red‐bellied Woodpecker removal experiments. Paradoxically, following the removal of Red‐bellied Woodpeckers, we observed decreases in Red‐cockaded Woodpecker group size, proportion of nests that were successful, and proportion of individuals remaining on territories. Removal of Red‐bellied Woodpeckers may have exaggerated the immigration rate of Red‐bellied Woodpeckers to Red‐cockaded Woodpecker territories. The Red‐cockaded Woodpeckers in the Apalachicola Ranger District likely can withstand pressure from immigrating Red‐bellied Woodpeckers given that their population has remained relatively stable despite the presence of Red‐bellied Woodpeckers. A major factor of population persistence in the Wakulla Ranger District was the high turnover rate of adult female Red‐cockaded Woodpeckers, a phenomenon that was exacerbated by removal of Red‐bellied Woodpeckers. Relying solely on observations of apparently competitive interactions between individuals may not necessarily provide information about population‐level outcomes. Paradoxically, removing species that appear to be competitors may harm species of concern.  相似文献   
15.
Abstract: Crayfishes are both a highly imperiled invertebrate group as well as one that has produced many invasive species, which have negatively affected freshwater ecosystems throughout the world. We performed a trait analysis for 77 crayfishes from the southeastern United States in an attempt to understand which biological and ecological traits make these species prone to imperilment or invasion, and to predict which species may face extinction or become invasive in the future. We evaluated biological and ecological traits with principal coordinate analysis and classification trees. Invasive and imperiled crayfishes occupied different positions in multivariate trait space, although crayfishes invasive at different scales (extraregional vs. extralimital) were also distinct. Extraregional crayfishes (large, high fecundity, habitat generalists) were most distinct from imperiled crayfishes (small, low fecundity, habitat specialists), thus supporting the “two sides of the same coin” hypothesis. Correct classification rates for assignment of crayfishes as invasive or imperiled were high (70–80%), even when excluding the highly predictive but potentially confounding trait of range size (75–90%). We identified a number of species that, although not currently listed as imperiled or found outside their native range, possess many of the life‐history and ecological traits characteristic of currently invasive or imperiled taxa. Such species exhibit a high latent risk of extinction or invasion and consequently should be the focus of proactive conservation or management strategies. Our results illustrate the utility of trait‐based approaches for taxonomic groups such as invertebrates, for which detailed species‐specific data are rare and conservation resources are chronically limited.  相似文献   
16.
Abstract: Many populations of marine megafauna, including seabirds, sea turtles, marine mammals, and elasmobranchs, have declined in recent decades due largely to anthropogenic mortality. To successfully conserve these long‐lived animals, efforts must be prioritized according to feasibility and the degree to which they address threats with the highest relative impacts on population dynamics. Recently, Wilcox and Donlan (2007, Frontiers in Ecology and the Environment) and Donlan and Wilcox (2008, Biological Invasions) proposed a conservation strategy of “compensatory mitigation” in which fishing industries offset bycatch of seabirds and sea turtles by funding eradication of invasive mammalian predators from the terrestrial reproductive sites of these marine animals . Although this is a creative and conceptually compelling approach, we find it flawed as a conservation tool because it has narrow applicability among marine megafauna, it does not address the most pervasive threats to marine megafauna, and it is logistically and financially infeasible. Invasive predator eradication does not adequately offset the most pressing threat to most marine megafauna populations—fisheries bycatch. For seabird populations, fisheries bycatch and invasive predators infrequently are overlapping threats. Invasive predators have limited population‐level impacts on sea turtles and marine mammals and no impacts on elasmobranchs, all of which are threatened by bycatch. Implementing compensatory mitigation in marine fisheries is unrealistic due to inadequate monitoring, control, and surveillance in the majority of fleets. Therefore, offsetting fisheries bycatch with eradication of invasive predators would be less likely to reverse population declines than reducing bycatch. We recommend that efforts to mitigate bycatch in marine capture fisheries should address multiple threats to sensitive bycatch species groups, but these efforts should first institute proven bycatch avoidance and reduction methods before considering compensatory mitigation.  相似文献   
17.
The WTC disaster provided an opportunity to look for ways to prevent morbidity among occupants of high-rise buildings during fires. This paper first describes the overall morbidity resulting from the explosion and fire, and second, presents the results of a case-control study carried out to identify risk factors for smoke-related morbidity. The main ones include: increased age, presence of a pre-existing cardio-pulmonary condition, entrapment in a lift and prolonged evacuation time. Study results point to the importance of the following safety systems during high-rise building fires: smoke-control systems with separate emergency power sources; lift-cars, lift-car position-monitoring systems, and lift-car communication systems with separate emergency power sources; two-way emergency communication systems on all floors and in stairwells; stairwells with emergency lighting and designed for the rapid egress of crowds; evacuation systems/equipment to assist in the evacuation of vulnerable people (elderly, infirm). Also important are evacuation plans that include regularly scheduled safety training and evacuation drills.  相似文献   
18.
Abstract:  Captive breeding is a commonly used strategy for species conservation. One risk of captive breeding is domestication selection—selection for traits that are advantageous in captivity but deleterious in the wild. Domestication selection is of particular concern for species that are bred in captivity for many generations and that have a high potential to interbreed with wild populations. Domestication is understood conceptually at a broad level, but relatively little is known about how natural selection differs empirically between wild and captive environments. We used genetic parentage analysis to measure natural selection on time of migration, weight, and morphology for a coho salmon ( Oncorhynchus kisutch ) population that was subdivided into captive and natural components. Our goal was to determine whether natural selection acting on the traits we measured differed significantly between the captive and natural environments. For males, larger individuals were favored in both the captive and natural environments in all years of the study, indicating that selection on these traits in captivity was similar to that in the wild. For females, selection on weight was significantly stronger in the natural environment than in the captive environment in 1 year and similar in the 2 environments in 2 other years. In both environments, there was evidence of selection for later time of return for both males and females. Selection on measured traits other than weight and run timing was relatively weak. Our results are a concrete example of how estimates of natural selection during captivity can be used to evaluate this common risk of captive breeding programs.  相似文献   
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