Trophic Relationships among Small Mammals in a Chilean Semiarid Thorn Scrub Community

Abstract

The food habits of seven species of small mammals were analyzed for a 15-month period during a live-trapping and snap-trapping study in a semiarid thorn scrub community in north-central Chile. The species included four cricetids (Akodon olivaceas, A. longipilis, Phyllotis darwini, and Oryzomys longicaudatus), two caviomorphs (Octodon degus and Abrocoma bennetti), 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 three functional trophic guilds and one 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.