Publicación Ocasional del Museo Nacional de Historia Natural, Chile 38: 61-104(1982)

Ecología de micro mamíferos de Chile central

Javier Simonetti; Ricardo Otaiza

Resumen

El objetivo primordial de este aporte es exponer sumariamente los principales problemas que es necesario enfrentar para lograr un desarrollo del conocimiento de los mamíferos fósiles chilenos más acorde con la concepción actual de las ciencias. Evidentemente, la Paleomastozoología en Chile se halla en este momento en situación desmedrada en comparación con otras disciplinas. La situación actual del estudio de los mamíferos fósiles de Chile es semejante a la que se plantea para los vertebrados fósiles en general. La gran mayoría de los hallazgos han sido fortuitos y de ningún modo corresponden a prospecciones programadas ni a una planificación determinada, ya que no existen líneas de investigación definidas. A pesar de ello, se ha logrado recolectar y conservar una cantidad considerable de fósiles. La mayor parte de ellos corresponde a animales pleistocénicos (Pleistoceno Superior) y en su mayoría se trata de restos parciales de esqueletos; sólo excepcionalmente se ha encontrado conjuntos óseos más completos y representativos.

Abstract

The knowledge achieved in the understanding of the ecology of the small mammals of the central Chilean matorral is reviewed. The goal is to determine the environmental factors that give account of their distribution and abundance. The information regarding predators, use of space, food habits, population dynamics and reproduction of 9 small mammal species (7 rodents, 1 marsupial and 1 lagomorph) is critically analyzed from the view point of resource use. Emphasis is made on the extent up to which this information can deny basic null hypotheses on the value of some environmental factors as resources for these small mammals. Predators can be considered as a resource for prey populations. All the small mammal species refered to above are found to be consurned by the local predators, conforming the most important portian of their diets. However, the information reviewed is insufficient to affirm that the predators affect the abundance of their prey, although it suggest that for sorne species it can influence their microdistribution. The data available on body size time of activity and macrohabitat preferences of both the predators and prey doesn't add light to the problem. Little work has been done on the use of space by small mammals. Microhabitat preferences are better understood for the species Octodon degus, which tends to use the space around shrubs and rocks more frecuently than open spaces and Oryctolagus which shows the opposi te pattern. The other mammals seem to behave more like O. degus, exhibiting a relatively high point diversity. Several factors such as predation, plant distribution and human interference may cause this pattern, but it can also be the result of sampling artefacts.