Tropical wetlands and land use changes: The case of oil palm in neotropical riverine floodplains.

Oil palm plantations are expanding in Latin America due to the global demand for food and biofuels, and much of this expansion has occurred at expense of important tropical ecosystems. Nevertheless, there is limited knowledge about effects on aquatic ecosystems near to oil palm-dominated landscapes. In this study, we used Landsat 7 ETM+, Landsat 8 OLI imagery and high-resolution images in Google Earth to map the current extent of oil palm plantations and determined prior land use land cover (LULC) in the Usumacinta River Basin as a case-study site. In addition, we assess the proximity of the crop with aquatic ecosystems distributed in the Usumacinta floodplains and their potential effects. Based on our findings, the most significant change was characterized by the expansion of oil palm crop areas mainly at expenses of regional rainforest and previously intervened lands (e.g. secondary vegetation and agriculture). Although aquatic ecosystem class (e.g. rivers, lagoons and channels) decreased in surface around 3% during the study period (2001-2017), the change was not due to the expansion of oil palm lands. However, we find that more than 50% of oil palm cultivations are near (between 500 and 3000 m) to aquatic ecosystems and this could have significant environmental impacts on sediment and water quality. Oil palm crops tend to spatially concentrate in the Upper Usumacinta ecoregion (Guatemala), which is recognized as an area of important fish endemism. We argue that the basic information generated in this study is essential to have better land use decision-making in a region that is relative newcomer to oil palm boom.