Vegetation Patterns in Response to Environmental Stress and Disturbance in the Papua New Guinea Highlands

Abstract

The vegetation of the highlands of Papua New Guinea is reviewed. Varied montane rainforests are extensive, but have been (and continue to be) cleared over large areas. Much forest variation can be related to altitude; past disturbances may also have been important. After clearance, forests are replaced by a range of non-forest vegetation types including gardens, both actively used and fallow. Over larger areas, especially in more densely populated parts of the highlands, frequently-burned grasslands also occur, and soils and vegetation are probably becoming progressively degraded. Mountain grasslands occur at high altitudes and their range has been extended by fire. The effects of stress and disturbance upon vegetation (as opposed to individual plants) are discussed. Vegetation responses to stress, disturbance, and combinations of both, involving reduction in stature and structural simplification, are described for the area above 3,300 m on Mt. Wilhelm.