A new study led by researchers from the Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences (NIGLAS) mapped 7.52 million kilometers of global riverfronts using satellite imagery and deep learning. They found that nearly 20% of these critical water-land transition zones are modified by agriculture and urban development. These human imprints, particularly concentrated in the "Low- and mid-latitude Afro-Eurasia Corridor" (LAEC), cause severe lateral fragmentation that degrades water quality and threatens freshwater biodiversity.

Rivers support human societies and biodiversity. Global assessments of anthropogenic impacts on rivers have traditionally focused on longitudinal alterations, such as dams. However, the riverfront, as the dynamic lateral transition zone buffering pollutants and providing habitat, has remained poorly mapped due to spatial resolution constraints. To address this gap, a research team led by Prof. SONG Chunqiao at NIGLAS developed the Global Riverbank rOUting Dataset (GROUD). Published in Nature Communications, the study utilized deep learning and high-resolution satellite imagery to classify 7.52 million kilometers of global riverfronts.

The study reveals that nearly 20% of global riverfronts have been transformed by human activity, predominantly driven by agricultural expansion (13.43%) and artificial built-up areas (6.29%). Notably, the researchers identified a continuous, highly developed belt termed the "Low- and mid-latitude Afro-Eurasia Corridor" (LAEC), which spans North Africa, Europe, West Asia, South Asia, and East Asia. This corridor contains approximately 60% of the world's human-imprinted riverfronts, exhibiting a modification density six times higher than regions outside the LAEC, which reflects a strong historical and modern societal dependency on these water resources.

Human imprints, particularly from agriculture and infrastructure, have caused extensive lateral fragmentation of natural riverfronts. This lateral fragmentation disrupts the natural buffering capacity of riverfronts, leading to a decline in the river's self-purification capabilities. The study found strong spatial correlations between highly modified riverfronts and elevated levels of total dissolved solids (TDS) and biochemical oxygen demand (BOD), with rivers inside the LAEC exhibiting significantly higher concentrations of both.

Furthermore, the loss of contiguous riverfront habitats poses a severe threat to biodiversity. The synergistic effects of lateral riverfront modification and longitudinal damming significantly escalate the risks for freshwater species, threatening 20.73% of amphibians and 16.60% of freshwater fishes where both stressors overlap globally. Within the LAEC specifically, this neglect contributes to the severe threat facing 34.02% of amphibians and 29.01% of freshwater fishes.

The researchers advocate that future river conservation efforts must evolve beyond traditional channel management to explicitly include the ecological integrity of lateral riverfront zones, employing nature-based solutions to restore connectivity.

The paper, "Human imprints on global riverfronts", was authored by Dr. ZENG Fanxuan, Prof. SONG Chunqiao, and international collaborators, and was published online in Nature Communications on July 18, 2026.