Search Results (6)

Fraxinus sogdiana Bunge is a class II key protected plant in China, known as the “living fossil of broad-leaved trees”. It is commonly found in multi-stemmed cespitose forms created by the sprouting of its root systems and stumps. We sampled plots in the east and west of the Kashi River in the Xinjiang Yili F. sogdiana National Nature Reserve. We investigated the cespitose F. sogdiana by using population ecology methods in order to provide scientific information for the conservation and sustainable development of the species as well as for the management of the reserve. We chose diameter class structure instead of age class structure to establish a population static life table, draw population survival and mortality curves, calculate a population dynamic index, and use spectral analysis to explore the fluctuation cycle of the population. The results show that age classes II–IV, comprising 74.72%, 91.53%, and 81.77% of the two cespitose populations in the east and west of the Kashi River and the total population, respectively, showed that the populations had a growing age structure. Still, there were very few individuals in age class I. The survival curves tended to be the Deevey–II type, with peak mortality occurring at age class IX in the east of the Kashi River and age class V in the west of the Kashi River. The dynamic index of populations changed the V_pi in the east and west of the Kashi River and the total population were greater than 0, indicating they were growing-type populations, and the V′_pi of the east of the Kashi River population was closer to 0, meaning that this population was relatively more resilient to external disturbances. Spectral analysis revealed that the periodic fluctuation of the population was mainly controlled by the biological characteristics of the population. Additionally, the east of the Kashi River population and the total population exhibited obvious multi-harmonic small periodic fluctuations. We suggest that the habitat of the cespitose F. sogdiana populations should be protected and improved to strengthen the nurturing management of individuals of age classes I and II for maintaining the natural renewal and development of the population. Full article

The tourism economy plays an essential role in supporting and driving tourism development. Therefore, studying its resilience is crucial for promoting sustainable and high-quality tourism development. The purpose of this study is to construct a tourism economic resilience evaluation index system and assess the tourism economic resilience of 10 counties and cities in the Ili River Valley from 2010 to 2019 using the entropy weight TOPSIS method. The results show that (1) the tourism economic resilience shows a “W”-shaped time-series dynamic development trend, especially a decline in 2012–2013 and 2015–2016; (2) the spatial pattern shows a non-equilibrium characteristic, with the northwestern part of the valley represented by Yining City showing a high level of resilience, and the central to southeastern counties and cities showing a lower level of resilience; (3) the spatio-temporal evolution steadily points to “northwest–southeast”, and there are five toughness convergence clubs, with obvious stability and neighborhood effects; (4) and the analysis of the driving factors shows that the number of employees in the tertiary industry, especially the input of high-quality talents, is crucial to improving the quality of services, strengthening the ability to withstand risks and the potential for development, and its impact is significant. These results provide an important reference for the formulation of tourism development strategies and promote the sustainable development of tourism. Full article

This study aims to clarify the relationship among the three systems of tourism industry, regional economy, and ecological environment in the Yili River Valley, which is essential for the sustainable development of the region. We explore the spatio-temporal evolution characteristics and influencing factors of the tourism–economy–ecosystem in the Yili River Valley using the center of gravity model, spatial mismatch index model, spatial variance model, and obstacle degree model, based on panel data from 2010 to 2019. The study shows that (1) the comprehensive development indices of the tourism industry, regional economy, and ecological environment in the Yili River Valley exhibit varying degrees of growth trends. Smaller increases are observed in ecological environment indices, while larger increases are found in regional economy and tourism industry indices. Both the regional economy and tourism industry indices share a strong correlation and similar development trends. (2) At the macro-regional scale, during the study period, the centers of gravity of the tourism industry, regional economy, and ecological environment in the Yili River Valley have consistently been separated from the spatial geometric center of the region. The degree of misalignment of the centers of gravity of the three systems as a whole has gradually reduced, indicating that the level of coordinated development of the region has continuously improved. (3) At the micro-regional scale, during the study period, most of the spatial misalignment indices of the Yili River Valley regions showed positive and negative fluctuations, and the types of misalignment varied to different degrees. However, the gap in spatial misalignment indices between different regions gradually narrowed, and the divergent characteristics of “east-west concentration, north-south dispersion” were gradually broken, with the overall indices showing a balanced development trend. (4) The spatial dislocation index of each region in the Yili River Valley is affected by multiple systems and factors, and the overall spatial dislocation factors are mainly the comprehensive utilization rate of general solid waste, exhaust gas emission, dust removal amount, etc., which mostly originate from the ecological environment system. Full article

Natural disasters, including collapse, landslides, and debris flows, commonly occur in the Yili River Valley as a result of its distinctive terrain and climate. A large proportion of these are loess landslides. Hence, studying the mechanism of their occurrence is crucial. The loess in the Yili River Valley has a high mica content. By using freeze-thaw (FT) cycling tests, unconsolidated and undrained triaxial shear tests, and FT cycling experiments, the study clarifies the impact of mica content on the mechanical properties of the loess in the Yili River Valley under FT cycling conditions. The findings demonstrated that the loess’s shear strength was negatively impacted by both the mica content and freeze-thaw cycles (FTCs). Under the same FT cycle conditions, the shear strength of the Yili Valley loess decreased with an increase in the mica content, particularly during the first ten cycles. Cohesion represented the impact of the mica content on the shear strength parameters. The cohesion decreases as the mica content increases. After ten cycles, the values of the cohesion tended to become stable, while the internal friction angle showed the opposite trend. For the same mica content, the shear strength of the Yili valley loess decreased with the increase in the number of FTCs, while the cohesion decreased, and the internal friction angle first increased and then decreased. The study’s findings might offer a theoretical foundation for preventing and reducing loess landslides in the Yili River Valley caused by FTCs and high mica content. Full article

Loess landslides caused by the dry-wet cycling processes are the most common geological disasters in the Yili region of China and have caused significant economic loss and casualties. Therefore, there is an urgency to study the mechanism of landslide disasters. However, research on loess landslide disasters under dry-wet cycling conditions in the Yili River Valley is still underdeveloped, and the research foundations are relatively weak. Based on the characteristics of high and stable mica content in Yili loess, this research probed the changes in shear strength and microstructure of loess with different mica contents (0%, 5%, 10%, and 15%) after different dry-wet cycles (0, 1, 3, 5, 7, 10, 15, and 20) using direct shear testing and a scanning electron microscopy. The results showed that the mica content had a negative relationship with the shear strength of loess. For the same number of dry-wet cycles, the higher the mica content was, the lower the loess’ shear strength, especially in the first five dry-wet cycles. The influence of mica content on shear strength parameters was not similar. The impact was more significant for cohesion. With increased mica content, cohesion gradually decreased. The effect was minor with the internal friction angle. With the rise in mica content, the angle slightly increased with slight variations. Under certain dry-wet cycling conditions, micro-particle content in the loess decreased continuously, the average reduction can reach 11.25%, the content of small and medium particles tends to increase, the average increments were 6.21% and 3.1%, and volatility changes in large particle content. However, the overall increasing trend remains. Accordingly, the number of micropores and small pores decreased, the average reduction was 7.63% and 5.48%, the number of medium pores and large pores increased, and the average increments were 6.13% and 6.99%, respectively. All these changes were more evident in the first three dry-wet cycles and when the mica content increased from 0% to 5%. This study will be beneficial as a reference for the occurrence mechanisms of loess landslide under dry-wet cycling conditions in the Yili area. Full article

Environmental managers and policymakers increasingly discuss trade-offs between ecosystem services (ESs). However, few studies have used nonlinear models to provide scenario-specific land-use planning. This study determined the effects of different future land use/land cover (LULC) scenarios on ESs in the Yili River Valley, China, and analyzed the trade-offs and synergistic response characteristics. We simulated land-use changes in the Yili River Valley during 2020–2030 under three different scenarios using a patch-generating land-use simulation (PLUS) model—business as usual (BAU), economic development (ED), and ecological conservation (EC). Subsequently, we evaluated the water yield (WY), carbon storage (CS), soil retention (SR), and nutrient export (NE) ESs by combining the PLUS and integrated valuation of ecosystem services and trade-offs (InVEST) models, thus exploring multiple trade-offs among these four ESs at a regional scale. For the BAU scenario, there are some synergistic effects between WY and SR in the Yili River Valley, in addition to significant trade-off effects between CS and NE. For the ED scenario, the rapid expansion of cropland and constructed land is at the expense of forested grassland, leading to a significant decline in ESs. For the EC scenario, the model predicted that the cumulative regional net future carbon storage, cumulative water retention, and cumulative soil conservation would all increase due to ecological engineering and the revegetation of riparian zones and that formerly steep agricultural land can be effective in improving ESs. Meanwhile, the trade-off effect would be significantly weakened between CS and NE. These results can inform decision makers on specific sites where ecological engineering is implemented. Our findings can enhance stakeholders’ understanding of the interactions between ESs indicators in different scenarios. Full article