The relationship between ecosystem services and human modification displays decoupling across global delta systems

The direct relationship between societal development and local ecosystem services breaks down at relatively minor levels of human modification of large river delta landscapes, according to a statistical analysis of 235 deltas. The ties between a society and its local ecosystem can decouple as societies develop and replace ecosystem services such as food or water regulation via trade and technology. River deltas have developed into important, yet threatened, urban, agricultural and industrial centres. Here, we use global spatial datasets to explore how 49 ecosystem services respond to four human modification indicators, e.g. population density, across 235 large deltas. We formed bundles of statistically correlated ecosystem services and examined if their relationship with modification changed. Decoupling of all robust ecosystem service bundles from at least one modification indicator was indicated in 34% of deltas, while 53% displayed decoupling for at least one bundle. Food-related ecosystem services increased with modification, while the other bundles declined. Our findings suggest two developmental pathways for deltas: as coupled agricultural systems risking irreversible local biodiversity loss; and as decoupled urban centres externalising the impact of their growing demands.

Automated summary

The direct relationship between societal development and local ecosystem services breaks down at relatively minor levels of human modification of large river delta landscapes. As societies develop, they replace ecosystem services such as food or water regulation through trade and technology, leading to a decoupling of society and its local ecosystem. River deltas have become important urban, agricultural, and industrial centers but are also under threat. The study found that some ecosystem services increased with human modifications, while others declined.