Effect of landscape modification on primate assemblages of the Magdalena River Valley, Colombia

Nestor Javier Roncancio Duque

doi:10.15446/caldasia.v43n2.84845

Abstract

Population and community dynamics are affected by local landscape disturbances, and the answer of each species to these changes could differentially affect species survival. Natural land cover in the Magdalena River valley, Colombia, has been reduced by almost 70 % and fragmented. There inhabit isolated and reduced populations of Alouatta seniculus, Ateles hybridus, Cebus versicolor, and Saguinus leucopus (Primates). To understand the effect of fragmentation over these species, the relationship between altitude, landscape and class metrics, and plant structure and diversity with the population density of these four primates in 20 localities were assessed. Additionally, the relationship between the density of A. hybridus, assumed as a better competitor, and the density of the other primates was assessed. Mean shape index was the most related variable and affected positively the density of A. hybridus, C. versicolor, and S. leucopus and negatively that of A. seniculus. Weight class index was the second more important variable, the four primates increased their density where more mature is the plant cover. Diameter at breast height was positively related with the density of A. hybridus and C. versicolor, negatively related for A. seniculus and not related to S. leucopus density. Tree density was related negatively with the density of A. seniculus and positively with S. leucopus. A. hybridus was related to the density of the other primates, positively to A. seniculus and negatively to the other two species.

Highlights

Anthropogenic disturbances such as logging and forest clearing constitute major threats to biodiversity (Michalski and Peres 2005)
C. versicolor was found in six localities with densities of 1.04 to 103 ind/km2, and A. seniculus was found in nine localities with densities of 0.21 to 75 ind/km2 (Table 3)
Campanas and Margaritas had the largest area of dense forest while Guarinocito and Fresno were the localities with largest areas of crops and pastures (Table 1; Weighted class index (WCI))

Summary

Introduction

Anthropogenic disturbances such as logging and forest clearing constitute major threats to biodiversity (Michalski and Peres 2005). When a disturbance changes environmental conditions, the natural community can suffer profound, immediate, and cumulative effects (Allesina et al 2006). The loss of a species or a change in its abundance, for those that interact with many other species, can have a considerable effect on ecological processes (Lindenmayer and Fischer 2013). It is, important to consider multiple anthropogenic factors when assessing the synergistic effects of human activities, in order to understand how species, respond in fragmented landscapes (Benchimol and Peres 2013)

Methods

Results

Conclusion