Lower Tarim River Research Articles

The influence of 10 years of water conveyances on groundwater and juvenile Populus euphratica of the lower Tarim River

The changes in the depth of groundwater were studied from the period before water conveyance through 2010, and the TDS of groundwater was analyzed in the lower reaches of the Tarim River during the period 2001–2010. Besides, the numbers of juvenile P. euphratica were investigated in the lower reaches of the Tarim River during the period 2001–2010. The findings indicate that: (1) the hydrological environment of the lower reaches has slowly deteriorated again; and (2) few juvenile P. euphratica were observed along the channel. These results show that the positive influence of the ecological water conveyance project on the ecosystem of the lower Tarim River should be beneficial in the long term; however, the long-term stability of the ecosystem cannot be achieved by the current water diversion scheme.

Groundwater circulation relative to water quality and vegetation in an arid transitional zone linking oasis, desert and river

In groundwater-dependent ecosystems, groundwater circulation controls the overall water quality and ecosystem dynamics. Groundwater and vegetation across a 30-km groundwater transect linking oasis, desert and river in an extremely arid area were investigated with a series of soil profiles drilled into the unsaturated zone to understand groundwater circulation and its control on groundwater quality and surface vegetation in the extremely arid Lower Tarim River, NW China. Measurements have included water-table depth, water chemistry and water isotopes (2H, 18O, 3H) for 15 water samples, soil moisture and chloride content for 11 soil profiles, and vegetation investigation. Results show that the groundwater in desert zone is characterized by slow recharge rate (pre-modern water), great water-table depth (6.17–9.43 m) and high salinity (15.32–26.50 g/L), while that in oasis (uncultivated land) and riparian zone is characterized by relatively fast recharge rate (modern water), small groundwater-table depth (3.56–8.36 m) and low salinity (1.25–1.95 g/L). Stable isotopes show that secondary evaporation takes place during irrigation in oasis. The vegetation characteristics (coverage, richness, evenness and number of plants) are closely related to soil moisture and water-table depth. Groundwater recharge from irrigation in oasis and from river in riparian zone sustains a better ecosystem than that in the desert area, where lateral and vertical groundwater recharge is limited. The more evapotranspirative enrichment may occur in the vegetated and water-rich riparian zone as compared to desert. This study also demonstrates the effectiveness of environmental tracers in studying ecohydrological processes in arid regions.

漫溢干扰过程中微地形对幼苗定居的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 漫溢干扰过程中微地形对幼苗定居的影响 DOI: 10.5846/stxb201105170646 作者: 作者单位: 中国科学院 新疆生态与地理研究所,中国科学院 新疆生态与地理研究所,新疆师范大学地理科学与旅游学院,新疆师范大学地理科学与旅游学院,新疆师范大学地理科学与旅游学院,中国科学院 新疆生态与地理研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目(30970549,40971284);自治区高校青年教师培育基金项目(XJEDU2008S41) Effects of the microhabitats on the seedling emergence during the flooding disturbance Author: Affiliation: Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Geography Science and Tourism Department of Xinjiang National University,Geography Science and Tourism Department of Xinjiang National University,Geography Science and Tourism Department of Xinjiang National University,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:通过对比漫溢干扰后边坡、坡中和坡底幼苗的物种组成、密度、幼苗周边的环境条件及土壤种子库的差异来分析漫溢干扰过程中,微地形对幼苗定居的影响。结果表明:(1)微地形对幼苗物种组成和生物多样性指数的影响很大。漫溢干扰后,位于边坡、坡中和坡底幼苗的Simpson多样性指数和Mcintosh均匀度指数在0.01的水平上差异极显著,Margalef丰富度指数在0.05的水平上差异显著。(2)微地形对土壤盐分含量影响很大。方差分析的结果表明,除HCO3-和K+外,边坡、坡中和坡底的pH值、CO32-、SO42-、Ca2+和Mg2+各指标在0.01的水平上差异极显著;全盐、总盐、Cl-和Na+各指标均在0.05的水平上差异显著。(3)微地形通过改变幼苗定居的环境条件,进而影响幼苗库的物种组成、密度和生物多样性指数。微地形中,幼苗库的各种生态指标均小于对应的土壤种子库的生态指标,从坡底到坡中到边坡,除单位面积上的植被密度外,土壤种子库和幼苗库的各项生态指标的变化趋势均不同。 Abstract:The Tarim River is the longest continental river in China and charactered by its fragile ecosystem in the word. The ecological processes of the Tarim River basin have undergone great changes due to the irrational human activities over the past 50 years, especially in the lower reaches of Tarim River. Therefore, the ecological water conveyance project(EWCP) has been implemented since 2000. The EWCP is an emergency plan for conserving the natural vegetation, controlling the desertification and improving the environment in the lower reaches of Tarim River. It transfers water from the Bosten Lake, to Daxihaizi Reservoir, and finally to Taitema Lake along the water channel. There have been 12 times of watering to the lower Tarim River during the period from 2000 to 2011. After the EWCP,the natural vegetation has obvious response to the water condition change. The studies on the soil seed bank in the region are very important to restoring the degraded ecosystem in lower reaches.Soil seed bank is the potential plant population or plant community. It plays an important role in occurrence, succession, and recovery process of vegetation. The germinated species and germinated seed number in soil seed bank determine the species composition and species number of seedlings in a certain degree. Meanwhile, the topography condition in the study areas is also an important factor on influencing germination ability of soil seed bank. Micro-topography impacts the seedling species composition and distribution pattern through the spatial differences in germination ability of soil seed bank, light, water and salt conditions. This paper takes the EWCP as a case study to analyze the effects of micro-topography on the seedling emergence during the flooding disturbance by the method of variance analysis. The species composition, seedling density, environmental condition and soil seed bank in three micro-topography type of the side slope, hillside and base of slope are compared after river flooding disturbance. The study results revealed that: (1) Species composition and diversity indices of the seedling were significantly influenced by different types of the micro-topography. After overflowing disturbance, Simpson index and Mcintosh index of seedling species in three types of micro-topography are aloes highly significant at the level of 0.01, and Margalef index is significantly different at the level of 0.05.(2) There is also a great effect on soil salt in the different micro-topography. The variance analysis showed that: except for the HCO3- and K+, the value of pH, CO32-, SO42-, Ca2+ and Mg2+ in three types of micro-topography are all significantly different at the level of 0.01, and the value to total salt, soluble salt, Cl- and Na+ are significantly different at the level of 0.05. (3) Micro-topography can affect the species composition, density and diversity indices of the seedling by changing the resided seedling's microhabitat. Under the condition of the micro-topography, the values of the ecological indicators in the seedling bank were less than those in the soil seed bank. From the base slope, hillside slope to side slope, the changing trends of the ecological indicators were different between the soil seed bank and seedling bank expect for the indicator of the vegetative density..The results can better reveal the impact mechanism of river flooding on compose and construction of the plant community, which has an important significance on the degraded ecosystem restoration. Furthermore, the results have a practical reference on protecting and recovering of the natural vegetation in the study region after river flooding interference. 参考文献 相似文献 引证文献

Land Resources Information Acquisition Based on Multi-Temporal TM Images

Selected the lower Tarim River in 2000 and 2010 TM / ETM data source, the use of human - machine interaction visual interpretation of data obtained by two interpretation map, interpret the results based on two data LUCC trends in variation analysis, the results show that: in the past 10 years, the Tarim River increased 28735 ha cultivated land (hm2), the natural increase of 25846 hectares of vegetation (hm2). Forest land was slowly decreasing trend, the decrease in the main area into open woodland and urban settlements; high, shrub and grass cover showed a degree of degradation. Conclusion: The study area in recent years has woodland, open forest land reduction and degradation shows the degradation of habitat area, with the increase of human reclamation area, the regional water consumption will significantly increase, which is lower Tarim river water to a certain pressure.

Multiple methods for calculating minimum ecological flux of the desiccated Lower Tarim River, Western China

ABSTRACTWe estimated the minimum ecological influx in the lower Tarim River via the wetted perimeter method using the curvature technique. Calculations were based on river geomorphology data during the fifth and sixth ecological water conveyances. Results showed that the minimum ecological influx of the three control sections of the river (Yinsu, Alagan, and Yiganbjima) were 2.85, 3.76, and 1.76 m3/s, which accounted for 9.7%, 14%, and 6.9% of the multi‐year average annual discharges, respectively. Except for the dry season, annual ecological water demand of the river was 0.79 × 108 m3, excluding evaporation and leakage. Multiple methods were used to prove the rationality of the results. It is by using the Tennant method that the percentage of minimum ecological influx accounting for multi‐year average flux varied from 6.9% to 14% (average 10.2%), which is considered normal for the maintenance of river habitat. It is by using the R2Cross method that the minimum ecological influx of the lower Tarim River was 2.935 m3/s. These calculation results mirror the actual situation and serve as the base of water‐source distribution in lower Tarim River. Further research is required to validate and adjust the results according to long‐term hydrographic observations. Copyright © 2012 John Wiley & Sons, Ltd.

Simulation and Evaluation of Ecohydrological Effect of Water Transfers at Alagan in Lower Tarim River

The riparian vegetation is highly dependent on the groundwater which is recharged by the river in arid regions. Water is the most important limiting factor for riparian vegetation in arid regions. From 1970s to 2000, the lower Tarim River almost dried up and the groundwater table fell down obviously. The riparian vegetation degraded seriously due to the low groundwater table. From 2000 to 2006, water transfers were implemented in the lower Tarim River to restore the ecological environment. Although the observation of groundwater and vegetation was carried out along lower Tarim River, the dynamics of the groundwater and vegetation along the cross section of the river were unknown. Ecohydrological evolution model on Riparian Vegetation in hyper-arid regions (ERV model) is a distributed ecohydrological model and has been validated at Yingsu in lower Tarim River. In this paper, the ERV model is applied to analyze the ecohydrological effect of water transfers at Alagan in lower Tarim River. At the same time, the ERV model is further validated. The simulation result is validated by observed groundwater table and vegetation coverage computed from remote sensing data. The result shows that the average groundwater table at Alagan increased by 4.74m from 2000 to 2006 and the average groundwater depth reached 6.36m. The average vegetation coverage increased from 0.130 to 0.194. In order to recover the green corridor, the further water transfers are required. The results are helpful for the ecohydrological research and water resources management in lower Tarim River.

On the relationship between historical land‐use change and water availability: the case of the lower Tarim River region in northwestern China

AbstractNatural ecosystems in the region of the lower Tarim River in northwestern China strongly deteriorated since the 1950s due to an expanding desertification. As a result, the downstream Tarim River reaches became permanently dry land. This historical evolution in land‐use change is typically the result of the anthropogenic impact on natural ecosystems. On the basis of a spatially distributed hydrological catchment model bidirectionally linked with a fully hydrodynamic MIKE11 river model, land‐use changes characterized by historical changes in leaf area index (LAI) of vegetation, as well as the evolution of irrigated surface areas, can be causally related to changes in water resources (groundwater storage and surface water resources). An increased surface area of irrigated (agricultural) land, together with a majority of inefficient irrigation methods, did lead to a strong increase of water resources consumption of the farmlands located in the upper Tarim River area. Evidently, this evolution influenced available water resources downstream in the Tarim basin. As a result, farmland has been gradually relocated to the upstream regions. This has led to reduced flows from the upper Tarim stream, which subsequently accelerated the dropping of the groundwater level downstream in the basin. This study moreover demonstrates that land surface biomass changes (cumulative LAI) along the lower Tarim River are strongly related to the changes in groundwater storage. Copyright © 2012 John Wiley & Sons, Ltd.

Ecohydrological evolution model on riparian vegetation in hyperarid regions and its validation in the lower reach of Tarim River

AbstractThe evolution of the ecohydrological system driven by external climatic forcing and internal feedbacks between vegetation and hydrology, which is more remarkable in arid and semiarid regions, has attracted substantial research attention in recent years. To examine critically the state‐of‐the‐art assumptions and dynamic equations used in the evolution study of an ecohydrological system, the rule of proceeding from simplicity to complexity should be followed. The riparian vegetation ecohydrological system in hyperarid regions (e.g. the lower Tarim River) can serve as a starting point given its simplicity, which has been seldom examined before in terms of system evolution. Further, the water transfer practice from 2000 to 2006 in the lower Tarim River serves as a valuable prototype experiment for model validation. This is because the remarkable changes in groundwater and vegetation in the area have taken place within a shorter period and thus can be easily observed. In the present study, the ecohydrological evolution model on riparian vegetation (ERV model) in hyperarid regions was proposed by coupling groundwater movement and vegetation dynamics. In the ERV model, the groundwater table serves as a critical feedback variable that determines the vegetation dynamics (colonization and mortality) and is determined by vegetation transpiration other than groundwater movement. The monitored groundwater table by wells and satellite‐observed vegetation coverage from the Moderate Resolution Imaging Spectroradiometer are used for model validation. The simulation results show the good performance of the ERV model with uncalibrated parameters. It was also calibrated manually using a multiobjective method, and the fine‐tuned parameters are close to the uncalibrated ones, indicating the robustness of the model. The analysis shows further that the increased evapotranspiration is substantially due to the water transfer and thus the vegetation growth, which implies the importance of ecohydrological coupling for long‐term hydrological modelling. Copyright © 2011 John Wiley & Sons, Ltd.

The variation in soil moisture and the appropriate groundwater table for desert riparian forest along the Lower Tarim River

Based on data collected over five years of monitoring the Lower Tarim River, we analyzed the variability of soil moisture content (SMC) and the relationship between SMC, groundwater table depth (GWD) and vegetation by using the methods of coefficient of variation (Cv), Pearson correlation and regression. The results of the variability of SMC indicate that it rose with increase in depth of soil layer — SMC in the soil layer of 0–60 cm was relatively small compared to SMC in the soil layer of 100–260 cm which showed a significant increase in variability. SMC and GWD before and after ecological water diversions exhibited significant differences at the site of the Yingsu transect and its vicinity of the watercourse, especially SMC in the soil layer of 100–260 cm increased significantly with a significant rise of GWD and reached maximum values at a GWD of about 4 m. Plant coverage and species diversity significantly improved with increases in SMC in the soil layer of 100–260 cm, both of them approached the maximum values and 92.3% of major plant species were able to grow when SMC was > 10%. To restore the ecosystem of desert riparian forest along the Lower Tarim River, the GWD must be maintained at < 4 m in the vicinity of the watercourse and at about 4 m for the rest of this arid region.

Evaluation of ecological restoration through vegetation patterns in the lower Tarim River, China with MODIS NDVI data

The lower Tarim River had dried up nearly 30 years before an ecological water diversion project (EWDP) for ecological restoration was implemented in 2000. Since then, eight intermittent water deliveries have been carried out for restoring this seriously degraded riparian ecosystem. To evaluate the efficacy and effectiveness of these operations, the Normalized Difference Vegetation Index (NDVI) data set derived from bands 1 and 2 of the MODerate -resolution Imaging Spectroradiometer (MODIS) on board NASA's Terra satellite was applied to identify the spatial and temporal variations of vegetation cover along the river corridor with about 320 km in length. The goal of this study is thus to generate seasonally integrated NDVI (SINDVI) in growing seasons between April and October so as to investigate a general vegetation patterns as well as examine the inter-annual SINDVI for discerning the status of ecosystem restoration. The spatiotemporal variations of vegetation cover were further characterized based on those inter-annual SINDVI data with the aid of Coefficient of Variation (CoV). Research findings indicate that ecosystem integrity was strengthened after a series of water diversion efforts and groundwater table control in the past few years. As the degree of ecosystem restoration is in progress, continuous operation of water diversion is still necessary in response to the needs for restoration of dense vegetation in the riparian buffer within this arid or semi-arid region.

Patch-level based vegetation change and environmental drivers in Tarim River drainage area of West China

Information on vegetation-related land cover change and the principle drivers is critical for environmental management and assessment of desertification processes in arid environments. In this study, we investigated patch-level based changes in vegetation and other major land cover types in lower Tarim River drainage area in Xinjiang, West China, and examined the impacts of environmental factors on those changes. Patterns of land cover change were analyzed for the time sequence of 1987-1999-2004 based on satellite-derived land classification maps, and their relationships with environmental factors were determined using Redundancy Analysis (RDA). Environmental variables used in the analysis included altitude, slope, aspect, patch shape index (fractal dimension), patch area, distance to water body, distance to settlements, and distance to main roads. We found that during the study period, 26% of the land experienced cover changes, much of which were the types from the natural riparian and upland vegetation to other land covers. The natural riparian and upland vegetation patches were transformed mostly to desert and some to farmlands, indicating expanding desertification processes of the region. A significant fraction of the natural riparian and upland vegetation experienced a phase of alkalinity before becoming desert, suggesting that drought is not the exclusive environmental driver of desertification in the study area. Overall, only a small proportion of the variance in vegetation-related land cover change is explainable by environmental variables included in this study, especially during 1987-1999, indicating that patch-level based vegetation change in this region is partly attributable to environmental perturbations. The apparent transformation from the natural riparian and upland vegetation to desert indicates an on-going process of desertification in the region.

Changes in groundwater induced by water diversion in the Lower Tarim River, Xinjiang Uygur, NW China: Evidence from environmental isotopes and water chemistry

summary The Lower Tarim River in NW China is under severe ecosystem degradation due to stopped stream flow and diminished groundwater recharge. Since year 2000, eight water diversions from the upper stream and from the neighboring Kaidu–Kongque River have been implemented to alleviate the ecosystem disaster. In order to assess the effectiveness of the water diversion project and to identify proper tracers of groundwater dynamics, we sampled the riparian groundwater system in 2007 and 2008 along the 350 km-long river channel through the 40 monitoring wells situated along nine transects perpendicular to the river and three soil profiles. Measurements on the samples have included environmental isotopes ( 18 O, 2 H, 3 H) and water chemistry. The results show that remarkable changes have been induced by the water diversions. The observed response of riparian groundwater system includes general decrease in total dissolved solid (TDS) and rise of water table. Scope with greater than 1 m rise in water table is within �700 m from the riverbank in the upper segments and �300 m in the lower ones. Greater rise of water table occurs near the river bank. Tritium data show that the extent of modern recharge (since 1960s), including that from the diverted water, is limited to 600 m from the riverbank at the upper segments and 200 m at the lower ones. Stable isotopes show that groundwaters, regardless of modern or pre-modern, are enriched in heavy isotopes and are plotted in parallel to the meteoric water line in the d–d plot, attributed to evaporation during recharge. Groundwater is generally of Na–Mg–Cl–SO4 type and is formed by dissolution of minerals, such as halite, sulfate, and carbonates, based on component correlation matrices analysis. The salinity of groundwater is mainly affected by that of the diverted water and of the local antecedent groundwater, salts in the unsaturated zone, evapotranspiration during recharge. As the zone of smaller groundwater depth (less than 5 m) suitable for the most existing Populus euphratica and Tamarix ramosissima, the main species targeted by the rescue effort, restricts to 200 m from the riverbank, and narrows down towards downstream, long-term stability of the ecosystem cannot be achieved by the current water diversion scheme and regulating/saving water in source-streams and the Upper/Middle Tarim River is crucial for continuing water diversion.

Ecological water demand of natural vegetation in the lower Tarim River

We have appraised the relationships between soil moisture, groundwater depth, and plant species diversity in the lower reaches of the Tarim River in western China, by analyzing field data from 25 monitoring wells across eight study sites and 25 permanent vegetation survey plots. It is noted that groundwater depth, soil moisture and plant species diversity are closely related. It has been proven that the critical phreatic water depth is five meters in the lower reaches of the Tarim River. We acquired the mean phreatic evaporation of different groundwater levels every month by averaging the two results of phreatic evaporation using the Qunk and Averyanov formulas. Based on different vegetation types and acreage with different groundwater depth, the total ecological water demand (EWD) of natural vegetation in 2005 was 2.4×108 m3 in the lower reaches of the Tarim River. Analyzing the monthly EWD, we found that the EWD in the growth season (from April to September) is 81% of the year’s total EWD. The EWD in May, June and July was 47% of the year’s total EWD, which indicates the best time for dispensing artificial water. This research aims at realizing the sustainable development of water resources and provides a scientific basis for water resource management and sound collocation of the Tarim River Basin.

Vegetation response to Ecological Water Diversion in the lower Tarim River, Xinjiang, China

Vegetation response to Ecological Water Diversion in the lower Tarim River, Xinjiang, China

Groundwater fluctuations induced by ecological water conveyance in the lower Tarim River, Xinjiang, China

Data from 40 monitoring wells across 9 sections of the lower Tarim River from 2000 to 2006 were analyzed to investigate the relationship between the transmission loss per unit river length and the change in groundwater depth. The relationship between the rise of the groundwater table (y) and the distance from the main river reach (x) was then assessed through regression analysis. We concluded that the maximum affected area was 1933 m away from the main river reach in the Alagan section, and the minimum affected area was 576 m away in the Kaogan section. In addition, after 8 water deliveries, the volume for recharging the groundwater was 78 248.7 × 10 4 m 3. Using the Yingsu section as an example, we found that the volume for recharging the groundwater decreased with additional periods of delivery except after the second and sixth water delivery The results revealed that the beneficial effect of an ecological water conveyance project on the ecosystem in the lower Tarim River is a long-term process. These findings may be useful for guiding studies on instream flow requirements and provide a scientific basis for implementing similar ecological projects in other areas.

The ecological characteristics of the riparian vegetation affected by river overflowing disturbance in the lower Tarim River

Based on data obtained from field investigations, this paper aims to analyze the influence of the river overflow on the desert riparian vegetation and discuss the function of the river overflow on the vegetation restoration at the lower Tarim River. The results show that (1) there are only 17 species, 13 genera and 9 families in the study areas before river overflow, while there are 34 species, 26 genera and 12 families after the overflowing in which 18 species emerged newly; (2) judging by the biodiversity indices, the species diversity and species richness in the river overflowed area increase more significantly than those in the un-overflow area; (3) judging by the importance of different species after years of river overflowing, the annual herbs germinate quickly at first, while the perennial herbs with deep roots or root clones become dominant in the plant community; (4) after several times of river overflowing, some arbors and shrubs such as Populus euphratica and Tamarix ramosissima germinate easily and can dominate gradually in the plant community. The results indicate that the river overflowing restores the severely degraded ecosystem in the lower Tarim River and the function is connected with restoration of eco-hydrological processes in the study areas. The results suggest that experimental overflowing has initiated a process of restoring ecosystem function within the riparian forest.

Effect of the ecological water conveyance project on environment in the Lower Tarim River, Xinjiang, China

The dynamic response of groundwater level is examined in traverse and lengthways directions. Take the Yinsu section for an example, we have simulated groundwater levels before and after water-conveyance every time and calculated the incidence of groundwater on the both sides of the river. It is noted that the effect keeps growing with the water-delivery times increasing, from 570 m after the first times to 3,334 m after the eighth times. In addition, this paper involves the temporal response of the natural vegetation to water conveyance, vegetation coverage, planted-species number, dominant position and species diversity from 2002 to 2006. The findings indicate that the positive influence of ecological water conveyance project (EWCP) on the ecosystem in the Lower Tarim River is a long-term process. In this paper, we try to calculate water required for recovery of damaged ecosystem by using data available. This project is likely the base of research on water demand and the reference of measures for research on ecological water conveyance effect.

The water transfer effects on agricultural development in the lower Tarim River, Xinjiang of China

The ecological process in the Tarim River, Xinjiang, northwest China, has undergone great changes due to human disturbance over the past 50 years. Most notably, alteration in the spatial-temporal pattern of water resources has resulted in a damaged or degraded vegetative ecosystem in the lower reaches of Tarim River, a condition that restricts local economical development. However, after raising the water level by watering to the lower Tarim River, such ecological degradation was obviously reversed within a certain region of the water channel. Both agricultural production and animal husbandry improved greatly as well. Taking the 35th state farm as an example, the areas utilized or available for farming increased greatly; furthermore, the total value of agricultural production is 1293.13 × 10 4 US$, increased by 128% (the rate between the increased production and the original one) after adoption of new management of water. Livestock population has experienced a growth trend as a result of water transfer compared before water transfer. The results of this investigation suggest that the reversible state of the eco-environment following watering has had a positive effect on local agricultural development. In addition, we analyzed the relationship between ecological change and agricultural development and discuss water resource management and its ecological significance.

Saving the "Green Corridor": Recharging Groundwater to Restore Riparian Forest Along the Lower Tarim River, China

Saving the "Green Corridor": Recharging Groundwater to Restore Riparian Forest Along the Lower Tarim River, China

The Natural Vegetation Responses to the Groundwater Change Resulting from Ecological Water Conveyances to the Lower Tarim River

This paper takes the ecological water conveyance project (EWCP) that transfers water from the Bosten Lake, to Daxihaizi Reservoir, and finally to the Taitema Lake as a case study to analyze the dynamic change of the groundwater depth, the vegetation responses to the elevation of the groundwater depth as well as the relationship between the groundwater depth and the natural vegetation. The results from many years' monitoring in field indicate: (1) the groundwater depth has been elevating gradually with the increase in the times of watering and the elevation range has been expanding continuously in the lower reaches of Tarim River. Correspondingly, the natural vegetation has a favorable response to the elevation of the groundwater depth. The change of the natural vegetation has accordance with that of the groundwater depth. Such facts not only show that groundwater is a key factor to the growth of the native vegetation but also prove it is feasible that the degraded ecosystem can be restored and protected by the EWCP; (2) the results of analysis of the spatial-temporal response of the natural vegetation to watering reveals that the beneficial influence of the EWCP on the ecosystem in the lower Tarim River is a long-term process; (3) in terms of the function and structure of ecosystem after watering in the lower reaches of Tarim River, the EWCP does not still reach the goal of ecological restoration at a large spatial scale at present. Based on such monitoring results, some countermeasures and suggestions for the future restoration strategy are proposed so as to provide a theoretical basis for restoring and protecting the ecosystem in Tarim River, and meanwhile it can also provide some scientific references for implementing the similar ecological projects in other areas.