Patterns and Processes in Forest Landscapes pp 107-124
Landscape-Scale Factors Influencing Forest Dynamics in Northern Australia
Understanding the extent and causes of savannah-forest dynamics in tropical regions is vital as small but widespread changes to tropical forests can have a major impact on global climate, biodiversity and human well-being. There is emerging evidence from aerial photography that an overall expansion of monsoon rainforests has occurred in northern Australia over the last few decades. Factors that may have driven the observed rainforest dynamics include the management of local scale disturbance events such as fire and buffalo numbers, as well as regional scale factors such as increases in rainfall and atmospheric CO$2$. Landscape ecology studies conducted in Kakadu National Park are provided as a case study as they together provide a cohesive methodology for investigating the consequences of management. The extent of boundary change at individual rainforest patches supported an effect of fire on the rainforest dynamics. The effect of historical buffalo impact was also supported by modelling analyses. However disturbance factors were unable to account for the overall expansion of rainforest. We conclude that fire and buffalo management have mediated the boundary dynamics. However, the overall boundary expansion is likely to have been primarily driven by factors that have shown similar increases during the study period, such as annual rainfall and atmospheric CO2. The methodology presented can be applied to forests in other regions and will contribute to ‘adaptive management’ programs, particularly with respect to fire management.
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