Using lake sediments to assess the long-term impacts of anthropogenic activity in tropical river deltas

Abstract

Tropical river deltas, and the social-ecological systems they sustain, are changing rapidly due to anthropogenic activity and climatic change. Baseline data to inform sustainable management options for resilient deltas is urgently needed and palaeolimnology (reconstructing past conditions from lake or wetland deposits) can provide crucial long-term perspectives needed to identify drivers and rates of change. We review how palaeolimnology can be a valuable tool for resource managers using three current issues facing tropical delta regions: hydrology and sediment supply, salinisation and nutrient pollution. The unique ability of palaeolimnological methods to untangle multiple stressors is also discussed. We demonstrate how palaeolimnology has been used to understand each of these issues, in other aquatic environments, to be incorporated into policy. Palaeolimnology is a key tool to understanding how anthropogenic influences interact with other environmental stressors, providing policymakers and resource managers with a 'big picture' view and possible holistic solutions that can be implemented.

Keywords: multiple stressors; palaeolimnology; resource management; river deltas; tropics.

Figure 1.

Stressors on river delta systems may be better understood using palaeolimnology. This diagram illustrates various stressors that may have significant impacts on delta systems, but sediments accumulating in aquatic sediments may hold clues as to how the system is responding over time, and if the systems are responding to management plans aimed at mitigating anthropogenic impacts.