Effects of habitat disturbance on the behavioral e

Authors: Barbara Sigman Decker

Publish Date: 1994/10/01

Volume: 15, Issue: 5, Pages: 703-

PDF Link

Abstract

Annual surveys in 1985–1987 revealed that since 1975 the total population of the Tana River red colobus Colobus badius rufomitratusdeclined by approximately 80 An intensive study in 1986–1988 of two groups of colobus in the Tana River Primate National Reserve indicated that habitat disturbance from the changing river course and shifting agricultural practices were primarily responsible for the decline Clearcutting around Mchelelo forest in the late 1960s compressed colobus populations to levels probably above the carrying capacity Between 1975 and 1986 primate population density declined dramatically the number of red colobus groups in Mchelelo forest decreased by half and the size of the remaining group was greatly reduced In 1986 there were fewer solitary colobus and small parties in the forest harem male takeovers did not occur infant survivorship increased and demographic parameters generally had improved The colobus groups in Mchelelo in 1973–1975 living at higher densities showed different feeding and ranging behaviors than 1986–1988 groups Range size was smaller in 1975 range overlap occurred and a greater portion of the forest was used per day and per month Mature leaves accounted for a much higher proportion of the diet Time spent feeding and resting was the same in both studies Social organization in predominantly one male groups was maintained and adult and subadult females transferred between groups

Keywords: