60 research outputs found

    Carnivore Translocations and Conservation: Insights from Population Models and Field Data for Fishers (Martes pennanti)

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    Translocations are frequently used to restore extirpated carnivore populations. Understanding the factors that influence translocation success is important because carnivore translocations can be time consuming, expensive, and controversial. Using population viability software, we modeled reintroductions of the fisher, a candidate for endangered or threatened status in the Pacific states of the US. Our model predicts that the most important factor influencing successful re-establishment of a fisher population is the number of adult females reintroduced (provided some males are also released). Data from 38 translocations of fishers in North America, including 30 reintroductions, 5 augmentations and 3 introductions, show that the number of females released was, indeed, a good predictor of success but that the number of males released, geographic region and proximity of the source population to the release site were also important predictors. The contradiction between model and data regarding males may relate to the assumption in the model that all males are equally good breeders. We hypothesize that many males may need to be released to insure a sufficient number of good breeders are included, probably large males. Seventy-seven percent of reintroductions with known outcomes (success or failure) succeeded; all 5 augmentations succeeded; but none of the 3 introductions succeeded. Reintroductions were instrumental in reestablishing fisher populations within their historical range and expanding the range from its most-contracted state (43% of the historical range) to its current state (68% of the historical range). To increase the likelihood of translocation success, we recommend that managers: 1) release as many fishers as possible, 2) release more females than males (55–60% females) when possible, 3) release as many adults as possible, especially large males, 4) release fishers from a nearby source population, 5) conduct a formal feasibility assessment, and 6) develop a comprehensive implementation plan that includes an active monitoring program

    The Fate of Airborne Polycyclic Organic Matter

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    Biological tests have shown that a significant part of the mutagenicity of organic extracts of collected airborne particulate matter is not due to polycyclic aromatic hydrocarbons (PAH). It is possible that part of these unknown compounds are transformation products of PAH. This survey focuses on the reaction of PAH in the atmosphere with other copollutants, such as nitrogen oxides, sulfur oxides, ozone and free radicals and their reaction products. Photochemically induced reactions of PAH are also included. The reactivity of particle-associated PAH is discussed in relation to the chemical composition and the physical properties of the carrier. Recommendations for future work are given

    Avaliação da quantidade de resíduos lenhosos em floresta não explorada e explorada com técnicas de redução de impactos, utilizando amostragem por linha interceptadora, no Médio Mojú, Amazônia Oriental, Brasil Evaluation of the amount of coarse woody debris in area of logged and undisturbed forests, using line-intercept sampling, in the Medium Moju River, Eastern Amazonia, Brazil

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    Neste trabalho são comparados os volumes de resíduos lenhosos, produzidos em uma área de floresta não explorada, com os de outra de floresta explorada, na propriedade denominada Fazenda Santa Marta (3º04'S, 49º14'W). Localizada na bacia hidrográfica do médio rio Moju, município homônimo, Nordeste do Estado do Pará, Amazônia Oriental. Os estudos foram realizados em área total de 426 ha, referentes a 4 Unidades de Trabalho das Unidades de Produção, sendo duas exploradas utilizando técnicas de impacto reduzido, totalizando 217 ha e as outras duas em floresta não exploradas, totalizando 209 ha. Foi testada a metodologia "amostragem por linha interceptora" como método para coleta e processamento dos dados sobre os resíduos lenhosos, em que foram utilizados 6.000 m de transectos para cada situação, totalizando 12.000 m de linhas de amostragem. Mediu-se todo o material lenhoso ainda caído sobre o piso florestal, com diâmetro superior a 10 cm, considerando o estado de decomposição das peças medidas. O volume médio estimado foi 82 m³ha-1 para floresta não explorada e 137 m³ha-1 para floresta após exploração de impacto reduzido.<br>This work compares the volumes of coarse woody debris produced in an area, with the another one logged forest by reduced impact logging methods, in called property Farm Saint Marta (3º04'S, 49º14'W). This locates-itself in the hidrográfic basin of the medium river Moju, city homonym, Northeast of the State of Pará, Eastern Amazônia. The studies had been carried through in total area of 426Ha, referring the 4 Units of Work immediate of forest management areas. Two of these units had been explored by reduced impact logging, totalizing 217Ha, and the others two in undisturberd forest totalizing 209Ha. It was used line intercept sampling for as method to quantify the coarse woody debris in 6,000 m of lines for each situation, totalizing 12,000 m of sampling lines. The fallen woody debris was measured on the forest floor, with superior diameter 10 cm, considering the diameter and the state of decomposition of the measured parts. The estimated volume was 82 m³ha-1 in undisturbed forest and 137 m3ha-1 in logged forest by reduced impact logging methods
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