Living with locusts: Connecting soil nitrogen, locust outbreaks, livelihoods, and livestock markets

Coupled human and natural systems (CHANS) are systems of feedback linking people and ecosystems. A feature of CHANS is that this ecological feedback connects people across time and space. Failing to account for these dynamic links results in intertemporal and spatial externalities, reaping benefits in the present but imposing costs on future and distant people, such as occurs with overgrazing. Recent findings about locust-nutrient dynamics create new opportunities to address spatiodynamic ecosystem externalities and develop new sustainable strategies to understand and manage locust outbreaks. These findings in northeast China demonstrate that excessive livestock grazing promotes locust outbreaks in an unexpected way: by lowering plant nitrogen content due to soil degradation. We use these human-locust-livestock-nutrient interactions in grasslands to illustrate CHANS concepts. Such empirical discoveries provide opportunities to address externalities such as locust outbreaks, but society's ability to act may be limited by preexisting institutional arrangements.