Oil palm expansion and land cover changes in the Peruvian Amazon: implications for forest conservation and fire mitigation
Land cover change is a major challenge for forest conservation in Amazonia. Forest cover loss and anticipated changes in climate are expected to increase fire incidence in Amazonia with detrimental consequences to human health, climate, and natural ecosystems. In this dissertation I developed remote sensing methods to map and quantify land cover changes attributed to oil palm expansion in the Peruvian Amazon between 2001 and 2010. Then I used these results to assess the role of oil palm expansion on achieving dual goals of agricultural production and forest conservation. Finally I developed maps of burned areas and combined them with the land cover data to model the contribution of land cover changes and variations in drought severity to fire occurrence and spread. I found that high yield oil palm expansion can be effective to reduce the use of land for achieving agricultural production but that incentives for expanding plantations outside forests are essential to guarantee forest conservation. Remote sensing methods developed in this work to map annual land cover conversion to oil palm demonstrated that the use of different satellite sensors is essential for a reliable and comprehensive monitoring of oil palm expansion, considering an assessment of the area expanded, the time of conversion and land cover transitions associated with the expansion of both large- and small-scale plantations. Results from the fire models showed that the area and spatial configuration of different land covers can have a significant influence on fire occurrence and spread but that the magnitude and sign of the correlation depend on drought severity, successional stage of regrowing vegetation and oil palm age. The results suggest that the promotion of forest regrowth and the establishment of oil palm plantations outside forests can be effective at reducing fire occurrence and spread when they develop beyond initial stages of growth and are protected during years of severe drought. Overall, irregular and scattered land cover patches can reduce fire spread, but in dry years fire spread can increase in pixels with more irregular and dispersed fallows and secondary forests. This dissertation contributes to understanding the effects of agricultural expansion and land cover changes on forest conservation and fire mitigation in Amazonia. Crop expansion can be a significant threat to forest conservation in Peru and other tropical countries with large forested areas still remaining. Forest conversion to agriculture can also increase landscape flammability in Amazonia, reducing the ability of the system to withstand the pervasive impacts of wildfires. Yet, this work shows that it is feasible to achieve both agricultural production and forest conservation if incentives to expand crops into already cleared lands are set in place. Not only can incentives reduce pressure on forests, but, in the case of oil palm, they also have the potential to mitigate wildfires if plantations are established outside forests and protected while they are young. Mechanisms for promoting forest regrowth could also be effective for fire mitigation if vegetation is protected against fire during dry years and also during early stages of development.
Geography, Environmental sciences, Ecology
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