Datos crudos de la publicacion titulada: Setting large- and medium-sized mammal restoration goals in one of the last mountain Chaco remnants from Central Argentina

Abstract

Background: Setting large- and - sized wild mammal (≥ 2 kg) restoration goals is important due to their role as ecosystem engineers and their generalized reduction in numbers. However, determining wild mammal restoration goals is very challenging due to the difficulties in obtaining data on current mammal density and due to unclear information on what mammal density values should be used as a reference. We study a small conservation area within one of the last remnants of the mountainous Chaco of central Argentina, where we suspect that extensive and unreported defaunation has occurred due to past human pressure and the introduction of non-native mammals. To conduct the analyses, we use and suggest a simplified technique that integrates methods used in rangeland and ecological sciences. Results: We detected eight native mammal species including only one herbivore species, and four non-native mammal species including three herbivores species during 6113 camera trap days distributed in 154 ha. We used known cattle densities as estimated by droppings and direct counts, together with the relative abundances indexes obtained from camera trap photos to calculate the densities of the other species, correcting for mammal size. Densities for the least and most abundant species of natives were 0.2 and 1.33 individuals km-2, respectively; and for non-natives 0.03 and 5.00 individuals km-2, respectively. Native and non-native species represented 0.8 and 99.2%, respectively, of the biomass estimates. For native herbivore biomass, estimated reference values as estimated from net primary productivity were 68 times higher than values estimated for the study area (3179 vs. 46.5 kg km-2). Conclusions: There is an urgent need to increase native mammals, with special emphasis on herbivore biomass and richness, while non-native mammal numbers must be reduced. As cattle is widespread in large portions of the globe and there is a lot of experience estimating their abundances, the ratio method we used extrapolating from cattle to other large- and medium- sized mammals could facilitate estimating mammal restoration goals in other small and defaunated areas where traditional methods are not feasible when target mammal densities get very low.