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Have Patagonian waterfowl been affected by the introduction of the American mink Mustela vison?
- Salvador J. Peris, Javier Sanguinetti, Moisés Pescador
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The American mink Mustela vison has spread widely beyond its native North American range and is associated with problems for the conservation of native species because of its impact as both predator and competitor. We investigated the impact of feral mink on waterfowl in Lanín National Park, south-west Neuquén, Patagonia, Argentina, an area in which the predator is currently expanding. Statistically significant differences were observed in the number of waterfowl species at lakes without mink (7.3 ± SE 0.7) compared to those with mink (4.0 ± SE 0.6). Overall abundance of birds observed per day was higher at lakes without (104.2 ± SE 20.6) than with mink (21.2 ± SE 22.3). The great grebe Podiceps major, speckled teal Anas flavirostris, Chiloe wigeon Anas sibilatrix and red-gartered coot Fulica armillata were more abundant on water bodies without mink, and flocks of the ashy-headed goose Chloephaga poliocephala were larger in areas without mink. Other species, such as the white-tufted grebe Rollandia rolland, coscoroba swan Coscoroba coscoroba, black-necked swan Cygnus melanocoryphus, cinnamon teal Anas cyanoptera, Andean duck Oxyura jamaicensis and Andean gull Larus serranus were never observed in areas harbouring mink. We conclude that at least 12 of the 25 waterfowl species observed are sensitive to the presence of the mink, either being absent or having a lower abundance where mink are present.
Status of the avifauna of San Rafael National Park, one of the last large fragments of Atlantic Forest in Paraguay
- Alberto Esquivel M., Salvador J. Peris, Rosendo Fraga, Robert P. Clay, Alejandro Bodrati, Hugo Del Castillo, Juan Klavins, Myriam C. Velázquez, Alberto Madroño
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- Bird Conservation International / Volume 17 / Issue 4 / December 2007
- Published online by Cambridge University Press:
- 03 December 2007, pp. 301-317
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We provide new information on all birds known from San Rafael National Park, Paraguay. Ornithological records from the period 1997 to 2006 have been reviewed, adding 112 new species to the reserve's avifauna. We provide data on the presence of 405 species in seven basic habitats types, and on their relative abundance. Biogeographically, San Rafael has a mixed avifauna, consisting of 70 Atlantic Forest endemic species, two Mesopotamian Grassland endemics, and many with a wider distribution in South America. At least 12 species are threatened and 16 near-threatened, including important populations of Dryocopus galeatus, Platyrinchus leucoryphus, Alectrurus tricolor and Xanthopsar flavus. We provide brief comments on records of these 28 species within the study site. The avifauna of the reserve is one the most important in Paraguay, due to its high diversity and endemism. At the same time, it is under great threat and its viability is at risk unless urgent actions are taken. Fragmentation of the Atlantic Forest in Paraguay has left the San Rafael block almost totally isolated from other forests. The degradation of its forests through selective logging and clearance for agriculture still has severe impacts, as do hunting and frequent fires in grasslands and forests. Unfortunately, the legal situation of the National Park is extremely precarious, creating great uncertainty and problems for its conservation.
Aqui relatamos nuevas informaciones sobre todas las aves conocidas hasta el presente dentro del Parque Nacional San Rafael. Se han revisado registros ornitológicos comprendidos entre los aãos 1997 y 2006, que han permitido aãadir 112 especies nuevas para la reserva. De esta manera, San Rafael tiene un total de 405 especies registradas. Para cada una de ellas se facilitan datos que documentan su presencia en siete tipos de hábitats básicos diferenciados, y de su abundancia relativa. Biogeográficamente, la avifauna de San Rafael es una mezcla que está compuesta por 70 especies endémicas del Bosque Atlántico, dos endémicas de los Pastizales de la Mesopotamia, y el resto, son de distribución más amplia en Sudamérica. Al menos, 12 especies están amenazadas y 16 casi-amenazadas, incluyendo poblaciones importantes de Dryocopus galeatus, Platyrinchus leucoryphus, Alectrurus tricolor y Xanthopsar flavus. De éstas 28 especies, se proporcionan comentarios breves sobre sus registros en el área de estudio. La avifauna de la reserva resulta una de las más importantes dentro del Paraguay, tanto por su mayor diversidad y presencia de endemismos, como por ser una de las áreas con alto potencial para mantener la biodiversidad, al tiempo que se encuentra sometida a fuertes amenazas que ponen en peligro su viabilidad en caso de no tomarse medidas urgentes. La alta fragmentación del Bosque Atlántico dentro del Paraguay, ha dejado al bloque de San Rafael prácticamente aislado de otros bosques. La degradación de sus bosques por tala selectiva y desmonte para agricultura son aún grandes impactos dentro de sus límites, así como la caza furtiva y la quema frecuente inducida de pastizales y bosques. Desafortunadamente, la situación legal del Parque Nacional es extremadamente precaria, generando así gran incertidumbre y dificultad para su conservación.