Reviews and syntheses: Anthropogenically breaking macro-ecospatial chains? – case review of HU Line

Abstract. Understanding of human-nature interactions is critical for global sustainability, but one of its frontier branches, regarding intentionally-positive anthropogenic feedbacks to environment at the macroecosystem scale, has been less studied. A concrete open question is whether people can break those chain-like macro-ecospatial transition zones. Based on remote sensing data and integrative data analysis, we examined this issue in the case of China, which both owns a macro-ecospatial transition zone top-ranked in the world – HU Line and has made massive environmental restoration efforts such as the Grain for Green Program (GGP). Literature reviews of the causes of HU Line revealed its natural formation, and spatiotemporal tests of its statuses indicated its contemporary stability, both telling the inherent difficulty of shaking macro-ecospatial chains. What's worse, the limited durations of those GGP-kind endeavors led to a debate on whether human will eventually exert positive or negative eco-effect on the evolution of HU Line. To handle this gap, we proposed using biogeographic, bioclimatology, and Earth system models in a simulation way and overviewed their potentials of reflecting the complex internal, external, and integral eco-functions in human deliberately improving nature. In all, the conclusion and proposal of this work are of fundamental implications for projecting the future of macro-ecospatial chains and pre-making polices for anthropogenically coping with global changes in land, environment, biology, ecology, and sustainability.