Human influences on the tropical forest wildlife

Extract

[...] Management of the logging methods can substantially reduce their impact on forest structure (actually increasing long-term yields), whilst careful planning of unlogged refugia and corridors may ensure the survival and recolonization of disturbance-sensitive species. Despite these mitigation measures, timber production cannot be seen as a panacea to the problems of forest wildlife conservation in the tropics. Reduced impact methods are rarely used, and still account for a very small proportion of the logging concessions in the tropics. Furthermore, very little data exist on the effects of repeated timber harvests at variable intervals, a necessary component if production forests are to remain economically viable. [...]

[...] Studies also differ depending on whether they examined tree fall gaps, or the entire logged forest matrix, in the latter case capturing many disturbance-intolerant species that are able to persist in unlogged refugia. Thirdly, some of the differences may be explained by geographic and historical factors. Production forests occur through- out the tropics, capturing many faunas that are unlikely to be equally adapted to disturbance. In the neotropics alone, logging appears to have greater impacts on the Amazonian avifauna than that in the Atlantic forest or in Belize, a difference that can be attributed to the more intensive history of natural disturbance events in those areas. [...]

[...] Aggravating Effects In frontier tropical forest regions, hunting and other forms of offtakes often co-occurs with different patterns of forest disturbance that can either aggravate or buffer the detrimental effects of faunal exploitation. For instance, effects of hunting are likely to be considerably aggravated by isolated forest fragmentation because fragments are more accessible to hunters, allow no (or very low rates of) recolonization from non harvested source populations, and may provide a lower-quality resource base for the frugivore–granivore vertebrate fauna. [...]

[...] While no information is available on the recovery of these forests it appears that the potential for the establishment of a recurrent burn regime in many tropical forests represents one of the largest contemporary threats to wildlife, as it can lead to the conversion of extensive closed-canopy forest lands into scrub savannas. This occurs concomitantly with the local extinction of almost all the forest wildlife typical of undisturbed forest. To a large degree wildfires in the humid tropics can represent an irreversible transition into replacement fire-climax ecosystems that provide considerably lower value both in terms of wildlife habitat and key ecosystem services. [...]

[...] Reasons why the scale and spatial extent of hunting activities have increased so greatly in recent years include human population growth and migration; severe reduction in forest cover and non- hunted source areas; increased access via logging roads and paved highways into remote forest areas allowing hunters to harvest wild meat for subsistence or cash; the use of efficient modern hunting technologies especially firearms and wire snares; and, in some regions, greatly increased trade in wild meat. Forest defaunation driven by wild meat hunters has therefore become one of the most difficult challenges for tropical forest wildlife conservation. In addition to drivers of the bushmeat harvest, wildlife depletion in tropical forests can be driven by extractive activities targeted to other desirable animal parts or products, including skins, feathers, ivory, horns, bones, fat deposits, eggs and nestlings, as well as live-captures of juveniles or adults for aviaries, aquaria, and the pet trade. [...]