Revista Científica SAREM–SBMz
Dora Grigera
Dora E. Grigera y Carmen A. Úbeda | Actualización de la categorización de los mamíferos de la Argentina
Ulyses F.J. Pardiñas | Comentarios sobre el III Congresso Brasileiro de Mastozoologia
Segundo Congreso de Mastozoología en Bolivia
I Congreso Boliviano de Ecología
Se estudió la composición estacional de la dieta del chinchillón (Lagidium viscacia) en el NO de la Patagonia argentina, mediante el análisis microhistológico de las heces. También se determinaron las preferencias alimentarias estivales en relación a la disponibilidad de alimento en el hábitat. La dieta anual del chinchillón se compone de 22 especies vegetales. Las gramíneas constituyeron casi el 68% de las especies consumidas y predominaron en todas las estaciones. Las especies arbustivas alcanzaron el 19.7%, las hierbas el 11%, y musgos, líquenes y especies arbóreas un porcentaje menor al 1%. Las especies más consumidas en promedio anual fueron Stipa sp., Festuca pallescens y Poa sp. En el verano existió un marcado consumo de estas dos últimas especies y del arbusto Schinus patagonicus. La variación estacional de la dieta no fue significativa y se relaciona a los ciclos fenológicos de la vegetación. Entre la dieta del otoño y del verano se registró la mayor similitud (79.3%), mientras que la menor similaridad se obtuvo entre el verano y el invierno (59.9%). La amplitud trófica (medida con el índice de Levins estandarizado, que asume valores entre 0 y 1) es baja y varía muy poco a lo largo del año (la mínima es 0.29 en el verano y la máxima 0.35 en primavera). Los resultados obtenidos indican que, en el área estudiada, el chinchillón es un especialista desde el punto de vista trófico, con marcada preferencia por las gramíneas.
Feeding habits of chinchillón (Lagidium viscacia, Chinchillidae) in northwestern Patagonia. Seasonal composition of the chinchillón diet in northwestern Patagonia was studied by microhistological analysis of faeces. Annual diet comprises 22 vegetal species, mainly grasses that made up nearly 68% of the consumed species and were predominant in all seasons. The remaining species in the diet were shrubs (19.7%), herbs (11%) and, in a proportion lesser than 1%, mosses, lichens and trees. The most consumed species were Stipa sp., Festuca pallescens and Poa sp. There were preferences in summer to these last two species and to the shrub Schinus patagonicus. Diet seasonal variations were not significant and are related to vegetation phenological cycles. The diets of autumn and summer showed the highest similarity (79.3%) whereas the lowest was found between summer and winter (59.9%). Trophic breadth (measured by standardized Levins’s index that renders values between 0 and 1) is narrow and shows low seasonal variation (lower trophic breadth is 0.29 in summer and the higher is 0.35 in spring). The results suggest that in the study area the chinchillón is a trophic specialist with a marked preference for grasses.
Las 339 especies de mamíferos autóctonos vivientes de la República Argentina fueron calificadas según su necesidad de conservación siguiendo las categorías de la ley 22.421 y su reglamentación, dando como resultado 15 especies Amenazadas de Extinción; 22 Vulnerables; 78 Raras; 22 Indeterminadas; 166 No Amenazadas; 33 Insuficientemente Conocidas, y 3 sin evaluación. La calificación se basó en el uso de una metodología de base y la participación de 33 expertos. La metodología utiliza un índice ordenador-orientador (SUMIN) el cual se genera a partir de factores de importancia para la supervivencia y la conservación de las especies. Sus resultados serán evaluados periódicamente por la SAREM.
Conservation priorities of the native mammals of Argentina. 339 recent native mammals species of Argentina were qualified according to their conservation status, following the Law 22.421 categories and its reglamentation. Their findings were: 15 Extintion Threatened Species; 22 Vulnerable; 78 Rare; 22 Indeterminate; 166 Not Threatened; 33 Insufficiently Known, and 3 not evaluated. This qualification was based on a basic methodological approach: a sorting and guiding index developed from the quantification of several important survival and conservation factors (SUMIN), and with the participation of 33 specialists. Their conclusions will be evaluated periodically by SAREM.
The conservation status of the fauna of mammals of the Nahuel Huapi National Park and Reserve is evaluated in the present work. All 32 resident and 5 marginal mammals in the study area were considered in the methodology which consists in assessing the degree of conservation of each species through an index made up by 12 survival-related variables. A list of species ordered according to their conservation indices for Argentina was obtained. The addition of two variables accounting for the particular situation of the species within the study area, allowed the elaboration of another list showing the conservation requirements for the Park and Reserve. Both ordinations were similar. The species in most critical conservation situation are the «huemul patagónico» (Hippocamelus bisulcus), the «huillín» (Lutra provocax), the «tuco-tuco colonial» (Ctenomys sociabilis) and the «gato huiña» (Felis guigna). The variables of the greatest influence upon the value of the index are those related to distribution and space-use plasticity. The results were compared with conservation evaluations of the same species made by other researchers and institutions. Differences and similitudes between evaluations were detected. Both the index value and its component variables provide an useful tool in making decisions for conservation and management.
This paper presents a methodology for ranking species according to conservation priorities, based on explicit, quantifiable criteria. Species are ranked through an index which is a sum of values assigned to 12 factors relevant to their survival: continental distribution, national distribution, extent of the use of habitat, extent of the use of vertical space, body size, reproductive potential, trophic amplitude, abundance, taxonomic singularity, singularity, extractive action and degree of protection of the species. The method was applied to 141 autochthonous tetrapod species of the Argentine Nothofagus forests. Results were compared to other qualifications by international and national organizations. The method is objective, and therefore repeatable and verifiable. It can be updated as new information becomes available. It is a useful guide for conservation and management, and because of its simplicity can expeditiously respond to concrete requirements. If the circumstances under which the method was calculated persist, it may become predictive.