Conserving primates in Colombian bamboo forest fragments: logging and landscape impacts on Red Howler Monkeys

Abstract

Increasingly, conservation of tropical forest-dwelling species depends on maintaining their populations in human-dominated landscapes. Often, extensive deforestation has left only fragmented forests that are subject to human use, such as logging, and this is the case in the central Andes of Colombia, where 200 years of human use has left only 15% of the forest, scattered in mostly very small, narrow fragments. This study evaluates the relationship impacts of both fragmentation and current bamboo forestry practices on red howler monkeys (Alouatta seniculus), the largest mammal remaining in this landscape. The underlying purpose of this study is to evaluate whether bamboo logging could be compatible with howlers' persistence in these forests, and if any changes in logging practice could improve prospects for howlers. A further goal is to identify opportunities to ameliorate the consequences of extreme habitat fragmentation, while providing benefits to the owners. Due to the fast growing characteristics of the bamboo, these forests could be used to increase habitat and to promote connectivity among fragments. Results of this study show both reasons to be optimistic and to be cautious about the prospects for bamboo forestry to be compatible with conservation of red howler monkeys. Bamboo logging does not directly impact the monkeys, who appear widely tolerant of logging activities since they do not impact their feeding trees. However, bamboo extraction damages seedling and sapling trees, which appear to recruit poorly in these forests, threatening the regeneration of the key food resources for the howlers. Combined with the impacts of fragment isolation, persistence of the howlers in this landscape likely depends on enhancing tree regeneration within logged bamboo fragments and expansion of existing fragments and creation of corridor or stepping stone habitats to promote movement of the monkeys among fragments. With relatively small changes in the implementation of management regulations, conservation of red howler monkeys could be greatly enhanced in this landscape.