Micromamíferos, cambio climático e impacto antrópico: ¿Cuánto han cambiado las comunidades del sur de América del Sur en los últimos 500 años?

TETA, P.; FORMOSO, A.; TAMMONE, M.; DE TOMMASO, D.; FERNÁNDEZ, F.; TORRES, J.; PARDIÑAS, U.F.J.

Therya

Asociación Mexicana de Mastozoología

Año: 2014 p. 7 - 38

2007-3364

Abstract.  Several lines of evidence suggest that the current configuration of small mammal communities ?i.e., richness (number of species) and diversity (distribution of species abundance)- in southern South America would have been generated in the period after the arrival of Europeans (1500 AD) . In this study, we reviewed the fossil record for small rodents and marsupials in the last 500 years, with emphasis on those of the Pampa and Patagonia. This evidence is compared with existing records from more than 700 owl pellet samples of the same geographical areas. As a first approximation, we found that richness and diversity of small mammal communities was higher in the previous step to the deepest human impact, with a sharp drop in both parameters to the present. It is suggested that the changes produced by livestock and agriculture have caused extensive habitat uniformity which was beneficial for some opportunistic taxa, facilitating their dispersion and allowing the increase of their populations. In the last 500 years, we recorded significant variations in the distribution of other taxa, which in some cases include local extinctions involving hundreds or thousands of miles. About 46 species of rodents considered as Least Concern by the IUCN and with fossil record for this time period, 23 (50 % ) have experienced drastic reductions in their range or abundance. At least 9 taxa would be completely extinct in South America, including 1 marsupial, 1 chiropteran and 7 rodents. Similar phenomena are recorded in other areas of the Southern Hemisphere, both in continental and island contexts. This panorama highlights the need to evaluate more carefully the status of some species with supposedly stable populations, but likely to be affected by future extensive changes in their environments (e.g., mining, expansion of the agricultural frontier), judging by that the fossil record showed.