MODELING THE EFFECTS OF FRAGMENTED HABITATS ON COSTA RICAN JAGUAR POPULATIONS*

摘要

1. Introduction. In recent years, biodiversity in Costa Rica has suffered a dramatic decline, due largely to habitat loss and fragmentation. In particular, this has had a severe effect on jaguar (Panthera onca) populations [6], which require vast expanses of territory in order to thrive. A single Central American jaguar can occupy anywhere from 10-40 km~2, depending on the sex, size, and location of the individual, and territories generally overlap very little [10]. These expansive habitat requirements have contributed to the jaguar's characterization as an "umbrella species" whose territorial needs encompass those of several other species [14]. As such, a healthy jaguar population is often indicative of a healthy ecosystem. Wildlife conservation is a prominent issue in Costa Rica. One of the most promising solutions proposed for fragmented ecosystems (both Costa Rican and otherwise) is that of connecting viable habitat patches with "corridors." However, habitat restoration is often expensive, and corridor efficacy is not well known. Costa Rican jaguars in particular have been studied empirically for many years, but there have been no attempts to model the population mathematically to our knowledge. This makes it difficult to predict the effects of conservation policy on population levels.