Comparative study of desertification control policies and regulations in representative countries of the Belt and Road Initiative

Impacts of human pressure and climate on biodiversity-multifunctionality relationships on the Qinghai-Tibetan Plateau

Many studies have investigated the effects of environmental context on biodiversity or multifunctionality in alpine regions, but it is uncertain how human pressure and climate may affect their relationships. Here, we combined the comparative map profile method with multivariate datasets to assess the spatial pattern of ecosystem multifunctionality and further identify the effects of human pressure and climate on the spatial distribution of biodiversity-multifunctionality relationships in alpine ecosystems of the Qinghai-Tibetan Plateau (QTP). Our results indicate that at least 93% of the areas in the study region show a positive correlation between biodiversity and ecosystem multifunctionality across the QTP. Biodiversity-multifunctionality relationships with increasing human pressure show a decreasing trend in the forest, alpine meadow, and alpine steppe ecosystems, while an opposite pattern was found in the alpine desert steppe ecosystem. More importantly, aridity significantly strengthened the synergistic relationship between biodiversity and ecosystem multifunctionality in forest and alpine meadow ecosystems. Taken together, our results provide insights into the importance of protecting and maintaining biodiversity and ecosystem multifunctionality in response to climate change and human pressure in the alpine region.

Effect of the Belt and Road Initiatives on Trade and Its Related LUCC and Ecosystem Services of Central Asian Nations

Economic development and trade activities are some of the main driving forces leading to land use and land cover changes (LUCC) with impacts on ecosystem services (ESs) functions. As the origin of the Belt and Road Initiative (BRI) initiated by China, Central Asia nations (CANs) provide a prism to examine the impact of LUCC and ESs changes brought by the BRI. The impacts of LUCC and ecological influences were evaluated. The land use transfer matrix and dynamic index, the Vector Autoregressive (VAR) model, the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST), the Carnegie Ames–Stanford Approach (CASA) model, and the Revised Wind Erosion Equation (RWEQ) model were used to evaluate the impact of export trade from the CANs to China (ETCC) on LUCC and ESs in the CANs before and after the BRI. Results showed that before and after BRI (2001–2020), agricultural land and construction land increased by 59,120 km2 and 7617 km2, respectively, while ecological land decreased by 66,737 km2. The annual growth rate of agricultural land and the annual reduction rate of ecological land after the BRI were higher than that before the BRI, while the annual growth rate of construction slowed down. Among the ecological land, the forestland increased by 5828 km2 continuously, while the grassland increased by 12,719 km2 and then decreased of 13,132 km2. The trends for LUCC spatial variation were similar. The development of ETCC positively affected the changes in agricultural and construction land in the CANs and negatively affected the changes in ecological land. The average contribution rates of the ETCC to changes in agriculture, construction, and ecological lands after the BRI were higher than those before the BRI. They increased by 5.01%, 3.33% and 5.01%, respectively. The ESs after the BRI improved compared with those before the BRI, indicating that, during short-term implementation of the BRI, ETCC growth also ensures the ecological protection of CANs. This study provides a reference for dealing with trade, land management and environmental protection relations between member countries of international economic alliances worldwide.

Natural Deterioration Processes of Salix psammophila Sand Barriers in Atmospheric Exposure Section

The atmospheric conditions of desert environments are important for the protection of Salix psammophila Sand Barrier, and these conditions can affect and change the structure and performance of the sand barrier, causing them to lose their wind proofing and sand fixing benefits. In this study, we have first examined the key environmental factors that affect the exposure of S. psammophila sand barrier. Then, we assessed how key factors in the desert atmospheric environment affect structural aging and performance. The relative crystallinity and chemical composition changes in the sand barrier were measured by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS), and the main degradation factors and processes were discussed. The results showed that the degradation degree of the exposed S. psammophila sand barrier was mainly affected by moisture and ultraviolet radiation. Lignin was the main component and the source of photodegradation and photodiscoloration observed in the sand barrier. However, other polysaccharides, such as cellulose and hemicellulose, were less affected by photodegradation. The stress generated by alternating desorption-absorption was the main cause of the expansion and contraction, deformation, cracking, and warping observed in S. psammophila sand barrier. We also found a series of irreversible changes and losses that occurred, which affected the natural material properties of S. psammophila sand barrier exposed to atmospheric conditions for several years. Exposure times between 5 and 7 years were the most important turning point in time for determining the deterioration of the S. psammophila sand barrier. Our results highlighted the importance of the interactions between atmospheric factors and the exposed atmospheric sections of the S. psammophila sand barrier from the perspective of environmental effects. However, the exact mechanisms of the sand barrier deterioration still need further investigation. Nevertheless, our overall findings advanced the current understanding of the environmental effects of S. psammophila sand barrier for ecological restoration and desertification reversal, especially in stressful desert environments.

Remote Sensing Monitoring and Evaluation of the Temporal and Spatial Changes in the Eco-Environment of a Typical Arid Land of the Tarim Basin in Western China

The eco-environment provides various spaces, conditions, and resources for human development, and their quality is a significant factor affecting sustainable development in a region. Most drylands face environmental fragility due to problems such as infertile land, scarce suitable living space, and a lack of resources. Therefore, investigating the temporal and spatial changes in the eco-environment of drylands is vital to developing them sustainably. This paper takes Hetian, which is located in the Tarim Basin of Western China and has typical features of an arid (or a hyper-arid) region, as the research area. The ecological index (EI) was used to construct a comprehensive ecological evaluation system, and five sub-indices (the biological richness index, vegetation coverage index, water network denseness index, land stress index, and pollution load index) were calculated to identify the quality and changes in the eco-environment of Hetian in 1995, 2009, and 2018. The results show that, from 1995 to 2018, the EI in Hetian showed a continuous downward trend (from 24.76 to 16.32), representing a change (ΔEI) of −8.44; this indicates significant deterioration in the quality of the local eco-environment. Large fluctuations in the EI also suggests that the environment in Hetian is very sensitive. In addition, the results revealed a degradation of Hetian, which includes a hyper-arid region.