Invasive exotic species of mammalian predators represent a major cause of vertebrate animal extinctions on islands, particularly those that lack native mammalian carnivores. In 2001, the American mink (Mustela vison) was recorded for the first time on Navarino Island, in the Cape Horn Biosphere Reserve (55° S) in Chile, representing the southernmost population of mink worldwide. In order to assess its potential impact on native fauna, we studied its diet on Navarino Island, as part of an integrative management program on invasive species. Over a three-year period (2005-2007) we collected 512 scats in semi-aquatic habitats: marine coasts, riparian and lake shores. Overall, the main prey was mammals (37 % biomass), and birds (36 %), followed by fish (24 %). Over the spring and summer, mink consumed significantly more birds, whereas mammals constituted the main prey over the autumn and winter when migratory birds had left the area. Among birds, the mink preyed mainly on adult Passeriformes, followed by Anseriformes and Pelecaniformes, caught as chicks. Among mammals, the exotic muskrat (Ondatra zibethicus) was the most important prey, and together with the native rodent Abrothrix xanthorhinus it accounted for 78 % of the biomass intake. For an integrated management of invasive exotic mammal species on Navarino Island and in the Cape Horn Biosphere Reserve it is important to further research interactions established here among the various introduced mammals, and to initiate immediate control of the mink population in its initial stage of invasion.

Background Combined treatment with a selective serotonin reuptake inhibitor (SSRI) plus mirtazapine has shown superior efficacy in some studies of depression but has not been studied in posttraumatic stress disorder (PTSD). This study aimed to assess acceptability of combined sertraline plus mirtazapine treatment for PTSD and to estimate its effect size relative to sertraline plus placebo. Methods Thirty-six adults with PTSD were randomized to 24 weeks of double-blind treatment with sertraline plus mirtazapine or sertraline plus placebo. Outcomes were analyzed with mixed effects models. Results The combined treatment group showed a significantly greater remission rate (P = 0.042) and improvement in depressive symptoms (P = 0.023) than the sertraline plus placebo group. There were no significant group differences in the two primary outcomes of treatment retention and PTSD severity, or in other secondary outcomes (sleep impairment, sexual functioning, quality of life, and physical and mental functioning), but the combined treatment group showed numerical advantages on all of these outcomes, and effect sizes relative to sertraline plus placebo ranged from small to moderate (d = 0.26 - 0.63). Both treatments were well-tolerated, with significantly increased appetite but not weight gain in the combined treatment group. Discussion Findings suggest that combined treatment of PTSD with sertraline plus mirtazapine may have clinically meaningful advantages in symptomatic improvement, relative to SSRI treatment alone, and acceptable tolerability. Conclusion Combined treatment with an SSRI plus mirtazapine in PTSD deserves additional study as initial treatment or as an augmentation strategy for nonresponders to an SSRI. Clinicaltrials.gov Identifier NCT01178671

Los humedales urbanos son sitios de alta biodiversidad pero que pueden estar bajo presión antrópica si no son bien manejados. En la ciudad de Punta Arenas (53°S), el humedal de Tres Puentes posee características únicas para conformar un sitio con todos los componentes de conservación (educación, investigación, desarrollo sostenible). Se reporta su composición y abundancia en especies de aves acuáticas durante 6 temporadas estivales. Se registraron 31 especies lo que corresponde al 50 % de las aves acuáticas continentales de la región de Magallanes. Se discute la variabilidad interanual y los posibles impactos producidos por el hombre.

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