A global assessment of the human pressure on the world's lakes

Millions of humans across the globe depend on lakes for numerous ecosystem services. Furthermore, humans use lakes as a food source and for a multitude of economic activities. Lakes are also essential to a plethora of taxa that rely on them for survival. Yet, despite the importance of lakes, we still lack an assessment of the extent lakes worldwide are being influenced by anthropogenic activities. In this study, I use the global database of lakes, the human footprint index from 1993 and 2009, and the more recent human modification index to measure the human pressure on the world's lakes. I found that one-third of the lakes are under considerable pressure. However, during the 16-year period examined, human pressure had increased in only 16% of the lakes, while it remained unchanged in 66%, and has even decreased in 18%. These patterns, though, were not uniform across the globe. Many lakes within tropical and subtropical regions, particularly in Africa—but also in South America and Asia—experienced sizeable increases in human pressure. Moreover, the percentage of lakes within Key Biodiversity Areas in which the human pressure had increased was three times larger the overall number. Although increases in human pressure were lower in lakes within protected areas—compared to lakes outside—there were numerous exceptions, particularly in the tropics. To protect biodiverse lakes in regions where human pressure is intensifying, it is important to improve the effectiveness of the protected areas and to address the socioeconomic factors driving the increases in human pressure.