Rainforest and savanna landscape dynamics in New Caledonia: Towards a mosaic of stable rainforest and savanna states?

摘要: Stable forested environments can be converted to savanna in response changes environmental disturbances. New Caledonia is a biodiversity hotspot; significant ecological and economic resources would lost if forests were turned into by anthropogenic changes. On the landscape scale, systems that have undergone shifts of this kind are characterized sharp forest–savanna boundaries mosaic-like distributions forest. Understanding locations dynamics such challenge for ecologists critical management conservation. Using time series aerial photographs (1955–2000) forest habitat suitability map, we tested hypothesis topography spatial processes, especially those relating fire spread seed dispersal, main determinants distribution rainforest Caledonian covering 24 km2. Within studied landscape, overall coverage decreased 24% between 1976 2000. This was primarily due contraction on west-facing slopes, which accounted about 90% total loss. Conversely, east-facing seemed contracted extensively prior period, confined refuges. A index calculated from landscape's topographical features using generalized additive models accurately predicted both presence probability expansion/contraction. We also provide evidence processes as dispersal limit expansion forests. Our results suggest rainforests slopes will progressively destroyed until they restricted refuges along thalwegs creeks, appears already happened their counterparts.