Ecology of small marsupials

Abstract

Marsupials are almost wholly confined to the Neotropical and Australasian regions of the world, where they comprise substantial components of the mammalian faunas. In South and Central America all 60 species are small and represent 7.4 per cent of the total mammalian species (Keast, 1972), while in New Guinea and Australia small marsupials represent 27 and 38 per cent respectively of the mammalian faunas (Ziegler, 1977; Keast, 1972). There are almost as many species of indigenous rodents in Australia as there are small marsupials, and in New Guinea and South America also small rodents and bats are as abundant or more abundant than marsupials (Table 8.1). In none of these three areas do marsupials occupy similar niches to species of either of the two other orders; there are no true flying marsupials and none is strictly seed-eating. The niches that small marsupials do occupy are those of small insectivores, small to medium carnivore/omnivore, and arboreal leaf-, fruit- and nectar-eater. In other regions of the world, especially tropical Africa and Asia, these niches are filled by tupaiids and prosimian primates such as tarsiers, pottos, lorises and lemurs, which do not occur in either Australasia or South America and by species of Insectivora, such as shrews, which are absent from Australasia and only extend into the most northerly parts of South America.