Maintaining terrace functions and benefiting human: a hard way to achieve the sustainability

Abstract:

Human-created terraced landscapes, considered as one of the most significant anthropogenic imprints, have been constructed extensively in diverse sloping terrains across the globe. Large-scale terraced landscapes were found in at least 74 countries over 5 continents, serving as pronounced evidence of agricultural civilization, ancient human histories, and diverse cultures. Meanwhile, terraces also play key roles in maintaining multiple ecosystem services but unfortunately facing many serious challenges which threaten terrace sustainability in the context of globe change. In our study, we firstly quantified the multiple effects of ecosystem services provided by terraces from different scales and regions. From the worldwide scale, A key terracing indicator, defined as the ratio of different ESs under terraced and non-terraced slopes (δ), was used to quantify the role of terracing in providing ESs. The most prominent role of terracing was found in erosion control (11.46 ±2.34), followed by runoff reduction (2.60 ± 1.79), biomass accumulation (1.94 ± 0.59), soil water recharge (1.20 ± 0.23), and nutrient enhancement (1.20 ± 0.48). Terracing, at least could also enhance the survival rates of plant seedlings, promote ecosystem restoration, and increase crop yield. From the national scale, such as the whole territory of China, the mean effect of terracing can increase carbon sink and soil water by 32.4% and 12.9%, respectively. From typical regions of the Loess Plateau, however, the values are relatively more variable (e.g., 0.87% ±0.82% to37.71% ±9.01% for soil moisture enhancement), which indicated that the specific situation, type and usage of terraces are also important for determining the results. Regarding the challenges and sustainability of terracing in practice and theoretical research, more detail discusses were also elaborated, all these efforts are expected to benefit for the better solutions of terracing management and sustainable development.