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San Carlos de Bariloche, Argentina

Fasola L.,University of Oxford | Fasola L.,CONICET | Muzio J.,National University of Comahue | Chehebar C.,Delegacion Regional Patagonia | And 2 more authors.
European Journal of Wildlife Research | Year: 2011

Following the establishment of American mink farms outside North America, the species has successfully invaded Europe and South America, and in some places, their presence demonstrably threatens native biodiversity. We surveyed for mink signs along the Andean Patagonian forest in Argentina from 38°52′ S to 54°52′ S, revealing that their range has now expanded to span 800 km of contiguous occupation on the continent including several types of wetlands and has also colonised Tierra del Fuego Island. Rate of expansion was estimated using two methodologies and varied between 5.53 and 9.00 km/year (linear method, large-scale spread) and 4.86 km/year (within a more restricted area, grid method). Diet throughout the region fitted the generalist pattern described for mink elsewhere. Native small mammals were the most frequently consumed category. Crustaceans (patchily distributed in the region) occurred in the diet in proportion to their availability (r s=0.961, p<0.001), but that of waterfowl did not (r s=0.178, p=0.713). Diet was evaluated at one lake throughout a year, revealing that consumption of crustaceans fell in the cold months when bird abundance increased. Based on published work on the impact of American mink as an introduced species in Patagonia and elsewhere, together with our own survey, we discuss the implications of this invasion for biodiversity conservation in Argentinean Patagonia and the associated dilemmas for management policy. © 2010 Springer-Verlag. Source


Invasive alien species management in Patagonia, Argentina: Prioritization, achievements and science-policy integration challenges identified by the National Parks Administration: Invasive alien species are a threat to biodiversity. Management options encompass prevention, early detection, eradication, control, exclusion and even "no action." More technical information is needed to achieve complex management actions successfully. In addition, managers and researchers address the problem with different approaches. Managers seek to prioritize management actions, and for researchers, these species are an opportunity to study basic and/or theoretical aspects, but not always applied to management. However, the management strategies offer a unique opportunity for both groups to work together seeking mutual benefits. Currently, management decisions are often based on experiences or information from other countries, which is not always useful for local problems. We present several management experiences in the Argentine National Parks Administration to show achievements, difficulties and challenges usually faced by managers. We found that: a) it is important, when resources are scarce, to generate effective prioritization tools and networks; b) it is also vital to involve the community in the management actions; c) on the other hand, research directly applied to pilot eradication is required; and d) also, a careful planning, and continuity and monitoring of management actions and environmental results based on different types of first class technical information, are key aspects for successful management. Finally, managers and researchers must ensure that the results of applied research are known and understood by decision makers and the general public, to secure management support. Source


Cassini M.H.,National University of Lujan | Fasola L.,University of Oxford | Chehebar C.,Delegacion Regional Patagonia | Macdonald D.W.,University of Oxford
Hydrobiologia | Year: 2010

The Southern river otter or huillín Lontra provocax has been classified as 'endangered', with the loss of riparian forest identified as the main threat to its survival. We used new information on distribution from Argentina to define their status. There are no data on the huillin's population structure and dynamics, and no estimate of its abundance or population trends at a relevant scale. Our survey teams covered 435 locations in lakes, rivers and coastal sites using a standard and repeatable methodology of 600 m survey transects as adopted for otter surveys across Europe. We found that its present geographic range in Argentina is slightly larger than is characteristic of a species at risk of extinction at the national level, although its contemporary distribution is still radically contracted in comparison to its historical distribution. © 2010 Springer Science+Business Media B.V. Source


Kitzberger T.,National University of Comahue | Araoz E.,National University of Tucuman | Gowda J.H.,National University of Comahue | Mermoz M.,Delegacion Regional Patagonia | Morales J.M.,National University of Comahue
Ecosystems | Year: 2012

The generalization that plant communities increase in flammability as they age and invariably lead to resilient self-organized landscape mosaics is being increasingly challenged. Plant communities often exhibit rapidly saturating or even hump-shaped age-flammability trajectories and landscapes often display strong non-linear behaviors, abrupt shifts, and self-reinforcing alternative community states. This plethora of fire-landscape interactions calls for a more general model that considers alternative age-flammability rules. We simulated landscape dynamics assuming communities that (1) increase in flammability with age and (2) gain flammability up to a certain age followed by a slight and moderate loss to a constant value. Simulations were run under combinations of ignition frequency and interannual climatic variability. Age-increasing fire probability promoted high resilience to changes in ignition frequency and climatic variability whereas humpbacked-shaped age-flammability led to strong non-linear behaviors. Moderate (20%) reductions in mature compared to peak flammability produced the least resilient behaviors. The relatively non-flammable mature forest matrix intersected by young flammable patches is prone to break up and disintegrate with slight increases in ignition/climate variability causing large-scale shifts in the fire regime because large fires were able to sweep through the more continuous young/flammable landscape. Contrary to the dominant perception, fire suppression in landscapes with positive feedbacks may effectively reduce fire occurrence by allowing less flammable later stage communities composed of longer lived, obligate seeders to replace earlier stages of light demanding, often more flammable resprouters. Conversely, increases in anthropogenic ignitions, a common global trend of many forested regions may, in synergism with increased climate variability, induce abrupt shifts, and large-scale forest degradation. © 2011 Springer Science+Business Media, LLC. Source

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