A new species of the genus Cymindis Latreille, 1805 (Coleoptera: Carabidae: Lebiini) from the Tarim River basin, China

A new species of the genus Cymindis Latreille, 1805 (Carabidae: Har¬palinae) is described from the Tarim River basin, border to the Taklamakan Desert, Xinjiang-Uygur Autonomous Region of China. Cymindis (Tarsostinus) rolandi sp. n. is similar to C. (Tarsostinus) equestris Gebler, 1825, but differs from the latter in the shape of the pronotum and the glabrous eyes.

Variable fuzzy evaluation model for water resources carrying capacity in the Tarim River Basin, China

As one of the most serious water-shortage regions of China, the shortage of water resources and ecological deuteration of the Tarim River Basin has increasingly attracted attention, and management and sustainable utilization of water resources rely mostly on the understanding of their carrying capacity. In the present study, water resources carrying capacity of the Tarim River Basin was evaluated using a multi-dimensional perspective of nature, society and economy factors based on a variable fuzzy evaluation model for the 2018 hydroclimatic conditions. Evaluation model results rated Aksu, Kizilsu, Kashi and Hotan districts as grade 2, where water resources current use and overexploitation have reached a relatively high level combined with a limited water resources carrying capacity. Bazhou district, where the water resources carrying capacity is relatively higher was evaluated and rated as grade 1 by the model. It is urgent to put forward some strategies in order to protect and improve the water resources carrying capacity in the Tarim River Basin which include promoting more efficient utilization of water conservation schemes, strengthening the long-term investment in environmental protection, improving the ratio of industrial wastewater treatment and reducing the industrial water quota. The results of the present study are aimed to be a beneficial guide in the planning and management of the Tarim's River basin water resources and possibly for other similar river basins.

The effects of ecological rehabilitation projects on the resilience of an extremely drought-prone desert riparian forest ecosystem in the Tarim River Basin, Xinjiang, China

The Tarim River Basin in Xinjiang, China, has a typical desert riparian forest ecosystem. Analysis of the resilience of this type of ecosystem under extreme drought conditions and ecological rehabilitation projects could provide a theoretical basis for understanding ecosystem stability and resistance, and provide new ecological rehabilitation measures to improve ecosystem resilience. We employed a quantitative framework to assess net primary productivity (NPP) resilience, emphasizing four aspects of NPP dynamics: NPP, NPP stability, NPP resistance, and maximum NPP potential. We compared ecosystem resilience across four time periods: before the implementation of ecological rehabilitation projects (1990–2000), during construction and partial implementation of ecological rehabilitation projects (2001–2012), during the initial project stage of ecological rehabilitation (2013–2015), and during the late project stage of ecological rehabilitation (2016–2018). There are three main finding of this research. (1) Mean NPP was increased significantly from 2013 and was decreased from 2016, especially in the main stream of the Tarim River and in the basins of eight of its nine tributary rivers. (2) Ecosystem resilience in 2013–2018 was greater than in 1990–2012, with the greatest NPP stability, mean NPP and NPP resistance, especially in part one of the river basin (the Aksu River, the Weigan-Kuche River, the Dina River, the Kaidu-Konqi River, and the main stream of the Tarim River). Ecosystem resilience in 2001–2012 was lowest when compared to 1990–2000 and 2013–2018, with lowest mean NPP, NPP stability, NPP resistance and maximum NPP potential, particularly in part two of the river basin (the Kashigr River, the Yarkand River and the Hotan River basins). Therefore, part one was most affected by ecological restoration projects. When 2013–2018 was divided into two distinct stages, 2013–2015 and 2016–2018, resilience in the latter stage was the lowest, with lowest mean NPP, NPP resistance and maximum NPP potential, especially in the main stream of the Tarim River. This may be due to unreasonable water conveyance in 2014–2015. (3) Ecological resilience has increased significantly in 2013–2015 after the implementation of ecological water transfer projects, river regulation, and natural vegetation enclosure projects. Ecosystem resilience could continue to increase even more in the future with the continued implementation of reasonable ecological water transfer projects.

Analysis of Characteristics and Driving Factors of Land-Use Changes in the Tarim River Basin from 1990 to 2018

Land-use and cover change is an important indicator for exploring global change trends, with in-depth research on land use and its driving factors being of particular significance in forging ecologically sustainable development. The present work used the Tarim River Basin as the study area, while the land-use transfer matrix, normalized difference vegetation index (NDVI), regional center-of-gravity model, and night-time-light remote-sensing mutual correction method were employed to explore temporal and spatial characteristics of land-use change and its driving factors. The results show the following. (1) From 1990 to 2018, land-use types in the study area significantly changed, with the cultivated land increasing by 73.9% and grassland area decreasing at a rate of 6.38 × 104 hm2 per year. (2) Areas with a natural vegetation NDVI above 0.2 appeared to follow a growth trend, with an area growth of 259.12 × 104 hm2 at a rate of 14.39 × 104 hm2/a. Average annual temperature and precipitation showed a fluctuating upward trend. (3) The center of gravity of land-use type area moved significantly. The center of gravity of cultivated land was moving in the same direction as the GDP and population center of gravity, migrating to the northeast. The migration distance of the center of gravity of cultivated land area was 212.59 km, the center of gravity migration rate of GDP was 14.44 km/a, and the population center of gravity was 812.21 km. (4) During the study period, the brightness of night lights in the study area was distributed in a circular shape, with more in the northwest and less in the southeast. Brightness gradually increased and showed an expansion trend, increasing from 0.3% to 6.3%. Among the influencing factors of spatial change of land-use change, natural factors such as climate change were related to the process of land-use/-cover change in the Tarim River Basin. Overall, human activities had the most obvious impact on land-use change.

Genetic Diversity and Population Differentiation of Kashgarian Loach (Triplophysa yarkandensis) in Xinjiang Tarim River Basin

The distribution of Triplophysa yarkandensis is restricted to Xinjiang’s Tarim River basin. We collected 119 T. yarkandensis samples from nine geographic populations in the Tarim River basin and utilized the RAD-seq method for SNP genotyping. In this study, a total of 164.81 Gb bases were generated with the Illumina platform, and 129,873 candidate SNPs were obtained with the Stacks pipeline for population genetic analyses. High levels of genetic diversity were detected among nine populations. The AMOVA results showed that the majority of genetic variations originated from among populations (FST = 0.67), and the pairwise FST values ranged from 0.4579 to 0.8736, indicating high levels of genetic differentiation among these populations. The discriminate analysis of principal components (DAPCs) and neighbor joining (NJ) tree revealed that the nine populations could be separated into two clusters (i.e., south and north populations), and modest genetic differentiation between south and north populations was observed, while the individuals from several populations were not clustered together by geographical location. The evidence of two genetic boundaries between south and north populations (except TTM) was supported by barrier analysis. The Bayesian skyline plotting indicated that T. yarkandensis populations in the Tarim River basin had not experienced genetic bottlenecks, and the effective population size remained stable. This study first clarified the genetic diversity and differentiation of T. yarkandensis populations in the Tarim River basin, and it provided valuable molecular data for conservation and management of natural populations.

Temporal variations in reference evapotranspiration in the Tarim River basin, Central Asia

Reference evapotranspiration (ET0) is important for agricultural production and the hydrological cycle. Knowledge of ET0 can aid the appropriate allocation of irrigation water in arid regions. This study analyzed the trends in ET0 over different timescales in the Tarim River basin (TRB), Central Asia. ET0 was calculated by the Penman-Monteith method using data from 1960–2017 from 30 meteorological stations located in the TRB. The Mann-Kendall (MK) test with trend-free prewhitening and Sen’s slope estimator were applied to detect trends in ET0 variation. The results showed that the mean ET0 decreased at a rate of 0.49 mm·10 a-1 on an annual timescale. The mean ET0 exhibited a decreasing trend in summer and increasing trends in other seasons. The effects of climatic factors on ET0 were assessed by sensitivity analysis and contribution rate analysis. Maximum temperature (Tmax), relative humidity (RH) and wind speed (WS) showed important effects on ET0. However, WS, which decreased, was the key element that induced changes in ET0 in the TRB. This work provides an important baseline for the management of agricultural water resources and scientific planning in agriculture.