Navegando por Assunto "Management"

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Artigo
Diet of invasive cats, rats and tegu lizards reveals impact over threatened species in a tropical island.
(Perspectives in Ecology and Conservation, 2020) Gaiotto, Juliana Vallim; Abrahão, Carlos Roberto; Dias, Ricardo Augusto; Bugoni, Leandro
Vertebrates introduced in non-native habitats have contributed to several extinctions in the modern era, with direct effects mainly over birds, mammals and reptiles on islands. Fernando de Noronha Archipelago, in tropical Atlantic Ocean, is a World Heritage natural site, holding the most diverse breeding seabird community off Brazil, in addition to endemic landbirds and reptiles. It also holds invasive black rats (Rattus rattus), tegu lizards (Salvator merianae) and feral cats (Felis catus), among the 26 exotic species reported in the archipelago, all of which are species with potentially high impact upon native fauna. Aiming to assess the role of exotic vertebrates on the fauna, we investigated their diets through stomach content and scat analysis, and stable isotope analysis (SIA) followed by isotopic mixing models. The main food items for tegu lizards were fruits, with relative importance (Prey-specific Index of Relative Importance – %PSIRI) of 41.3%, and the endemic Noronha skink (Trachylepis atlantica; 19.6%) and for black rats was Noronha skink (30.3%). The diet of feral cats was composed by rodents (31.6%), birds (28.6%) and Noronha skink (18.8%). SIA and Bayesian mixing models provided evidences that invasive species use marine matter to synthesize tissues, probably derived directly or indirectly from seabird colonies. This study demonstrated that exotic species feed on other exotic, as well as endemic species. The most heavily impacted species was the endemic Noronha skink. We demonstrated the predation pressure of exotic fauna upon endemic vertebrates, and strongly recommend the implementation of an invasive species control and eradication plan.
Artigo
Prospects for domestic and feral Cat management on an inhabited tropical island.
(Biological Invasions, 2017) Dias, Ricardo Augusto; Abrahão, Carlos Roberto; Micheletti, Tatiane; Mangini, Paulo Rogério; Gasparotto, Vinícius Peron de Oliveira; Pena, Hilda Fátima de Jesus; Ferreira, Fernando; Russell, James Charles; Silva, Jean Carlos Ramos
Cat management campaigns have been implemented on several islands worldwide. However, few successful campaigns have occurred on permanently inhabited islands. Cats are known for causing severe impacts on the native insular fauna, posing an important threat to biodiversity. Moreover, this species is also responsible for zoonosis maintenance and transmission. A thorough understanding of cat population structure (e.g., supervised vs. unsupervised) is strongly suggested as a management action on inhabited islands, as it might promote more efficient and effective management of this species. Fernando de Noronha is an archipelago in the tropical Atlantic Ocean. The total cat population on the main island was estimated at 1287 animals, most of them supervised and subsidized around inhabited areas. Free-roaming cats currently threaten the endemic terrestrial fauna of Fernando de Noronha, and the cat density found by the present work is among the highest ever recorded on an island. Using population dynamic simulations, the long-term effects of reproduction control and removal of cats from the archipelago were assessed. Removal of cats was also suggested as a necessary management strategy to achieve negative population growth. In addition, it was more cost-effective than reproduction control. However, applying both removal and sterilization strategies to this population resulted in a higher population decrease than removal alone. For these reasons, a combination of reproductive control and cat eradication should be implemented in Fernando de Noronha.