TROPHIC RELATIONSHIPS AMONG SMALL MAMMALS IN A CHILEAN SEMI-ARID THORN SCRUB COMMUNITY

The food habits of 7 spp. of small mammals were analyzed for a 15 period during a live-trapping snap-trapping study in a semiarid thorn scrub community in northcentral Chile. The species included 4 cricetids (Akodon olivaceus, A. longipilis, Phyllotis darwin and Oryzomys longicaudatus), 2 caviomorphs (Octodon degus and Abrocoma bennetii) and a didelphid Marmosa elegans). The community was characterized by a semiarid mediterranean climate with low winter precipitation and frequent fog formation. Dominant physical features included high cover of spiny evergreen and drought-deciduous shrubs, low ground cover of herbaceous plants and open sandy areas. Year-round food habit trends indicated 3 functional trophic guilds and 1 omnivorous species. A. longipilis and M. elegans were insectivorous, O. degus and A. bennetti were herbivorous, P. darwini and O. longicaudatus were granivorous and A. olivaceus was omnivorous. This pattern of trophic specialization agrees generally with other studies of various species in the Chilean region and suggests contrasts with patterns in the mediterranean and desert communities of North America and Argentina.