congresos y reuniones científicas
Climate and land use intensity shape forest-meadow ecotones in subtropical montane systems
Congreso; Landscape ecology International conference; 2010
International Union of Forest Research Organizations
I used SELES (Spatially Explicit Landscape Event Simulator) to build a spatially explicit dynamic model of forest-meadow dynamics in north-western argentinean montane systems. I combined dendrochronological, historical, experimental and satellite imagery based data to parameterize the model. The model permitted to handle the complexity of a system that involves non-linear interactions between grazing intensity, climate conditions, human fire ignition, fire events, seed dispersal and tree colonization. I ran the model for 50 years under different land use, climatic and fire policy conditions. For each variables I determined three states, generating 27 scenarios: present, a 50% reduced and a 25% increased land use intensity; present, 25% increased and 25% decreased rainfall; and no fire policy, a 50% reduction of fire ignitions policy and a total suppression of fire sources with active fire-fighting policy. I quantified the forested area for 10 runs under each scenario. Under most of the scenarios forests encroached over meadows. Forest area diminished whenever rainfall decrease was associated with grazing increase but mainly when fires were totally suppressed from the system. These results suggest that under the most plausible scenario (further land abandonment and rainfall increase) forest will continue to encroach if we do not suppress fires totally.