Monitoring mammal populations in Costa Rican protected areas under different hunting restrictions

If is necessary to assess whether the management of protected areas is achi eving the objectives set for them. In particular, changes and trends in wil dlife populations should be documented. We compared the 1990 abundance of m ammals in two Costa Rican protected areas Corcovado National Park (CNP) and Golfo Dulce Forest Reserve (GDFR), with similar environmental characterist ics bat different hunting restrictions and levels of protection. We also mo nitored the abundance of mammals in CNP over a 4-year period. We also devis ed an inexpensive method of monitoring tropical rainforest mammal populatio ns in a timely and efficient manner. The method is based on the use of mamm al track records and arboreal mammal sightings and requires little effort. With this method 20 mammal species were recorded at CNP and 15 at GDFR. Spe cies were consistently less abundant in GDFR than in CNP, principally those species preferred by hunters. Species were grouped according to whether or not they are used as food and whether they are locally or globally threate ned or not threatened. The abundance of all these groups of species in GDFR was 6-28% the abundance in CNP. During 1990-1994, overall mammal abundance in CNP remained relatively stable, but there was considerable variability among species. As a group, both species used for food and globally threaten ed species declined in abundance during that period in CNP. The abundance o f all groups of species declined from 1992 to 1994, coinciding with a reduc tion in hunting vigilance at CNP. Evidence suggests that the main factor di fferentiating the abundance of mammals in the two protected areas, and at C NP during the study period, was the level of hunting. Golfo Dulce Forest Re serve seems to be achieving only partial success in protecting wildlife, wh ereas Corcovado National Park seems to be considerably more effective, alth ough not entirely successful.