Investigaciones en ejecución / Research in progress:

Reduced impact logging and the conservation of understorey insectivorous birds in a Bolivian lowland tropical forest

Researcher: Adam Felton
Institution: Centre for Resource and Environmental Studies, Australian National University, Australia
Research Site: La Chonta
Dates: August 2003 to December 2004

Approximately six million hectares of tropical forests are opened up for the first time to selective logging every year. If harvested sustainably it is hoped that these forests will maintain their original biodiversity while still providing much needed revenue to local communities. One form of sustainable timber harvesting now being trialed in the tropics is reduced impact logging (RIL). This type of timber extraction combines planned low intensity logging with low impact silviculture techniques. RIL is being increasingly adopted throughout the tropical world to the point where over 5 million hectares of tropical forest are logged each year using these techniques. The principal goal of RIL is to provide sufficient economic incentives to retain tropical forests without impacting on rainforest biodiversity.

Unfortunately at the present time there is insufficient scientific support for the view that tropical forests can sustain economic yields of timber production while at the same time maintain biodiversity. Although reduced impact logging is guided by the principle of sustainability, it is a form of extractive exploitation that inevitably causes a variety of changes to the structure and physical environment of the forest. This type of forest disturbance may induce long-term changes in the species composition and population sizes of some communities. It is therefore vital that if RIL is to become a widespread practice throughout the tropics that we try to understand what can and cannot be hoped for from this practice.

Studies of logging have consistently demonstrated that understorey insectivorous birds are extremely sensitive to forest disturbance. In the tropical forests of Asia, Africa and South America researchers have reported declines or local extinctions of understorey insectivorous birds when forests were subjected to conventional forms of selective logging. If RIL is to provide the conservation benefits needed in the tropics, then the degree to which forests subjected to RIL maintain this sensitive and diverse avian guild must be assessed. The primary goal of this project will be to assess the degree to which a tropical lowland forest subjected to RIL maintains the community composition and abundance of one of the most disturbance sensitive and dominant avian guilds, the understorey insectivores.