Desert riparian vegetation and groundwater in the lower reaches of the Tarim River basin

AbstractThe Green Corridor in the lower reaches of Tarim River in northwestern China has an extreme hot and dry climate. Vegetation here, consisting of arbor, shrub and grass, relies on groundwater exceedingly. However, the increasing anthropogenic activities of large-scale agricultural reclamation and unreasonable water utilization in the upper and middle reaches caused the 321-km riverway in the lower reaches to dry up completely in 1972 and resulted in the sharp decline of groundwater, followed by the ruin of desert riparian vegetation on a large scale. The Green Corridor is on the verge of shrinking. Water has a key role in maintaining ecological balance and socioeconomic development. This paper, focused on the relationship between vegetation and groundwater, discusses (1) the change of groundwater table caused by the ecological water delivery carried out in the lower reaches of Tarim River; (2) the appropriate groundwater depth meeting the vegetation’s survival; (3) the minimum ecological flux and ecological water requirement for the growth of natural vegetation. It was shown that (1) based on the analysis of the monitoring data from the groundwater level of ten times water delivery, such an extensive artificial watering takes positive effect on raising the groundwater level along the two sides of the river; (2) a groundwater table depth of 2–4 m is probably the appropriate ecological water table level for the lower reaches of the Tarim River, and 6 m is the threshold for the local vegetation; (3) at the lower Tarim River, 1.157 × 108 m3 of water flow is needed for itself. The longer the duration of water releases, the greater would be the groundwater rise and the larger the range of vegetation influenced. It was found that the duration and volume of water delivery was closely related to restoration of vegetation in the lower reaches of the Tarim River. The goal of this paper is to offer scientific evidences for water delivery in the rigorous areas to maintain an ecological balance.

[1]  P. Cook,et al.  Groundwater use by vegetation in a tropical savanna riparian zone (Daly River, Australia) , 2005 .

[2]  A. Grootjans,et al.  Groundwater variables and vegetation in dune slacks , 2001 .

[3]  Claude E. Shannon,et al.  The Mathematical Theory of Communication , 1950 .

[4]  Yaning Chen,et al.  Response of groundwater chemistry to water deliveries in the lower reaches of Tarim River, Northwest China , 2008 .

[5]  Chen Yaning,et al.  The Influence of Groundwater on Vegetation in the Lower Reaches of Tarim River,China , 2003 .

[6]  Xiangjun Tian,et al.  Prediction of water table depths under soil water-groundwater interaction and stream water conveyance , 2011 .

[7]  Donald L. Tennant.  Instream Flow Regimens for Fish, Wildlife, Recreation and Related Environmental Resources , 1976 .

[8]  Yaning Chen,et al.  Physiological Responses of Three Contrasting Plant Species to Groundwater Level Changes in an Arid Environment , 2006 .

[9]  M. Hill,et al.  Reciprocal Averaging : an eigenvector method of ordination , 1973 .

[10]  Paul A. Racey,et al.  Large‐scale processes in ecology and hydrology , 2000 .

[11]  Brad R. Murray,et al.  A functional methodology for determining the groundwater regime needed to maintain the health of groundwater-dependent vegetation , 2006 .

[12]  Rauno V. Alatalo,et al.  Problems in the measurement of evenness in ecology , 1981 .

[13]  Juan Wu,et al.  The influence of water conveyances on restoration of vegetation to the lower reaches of Tarim River , 2010 .

[14]  Robert K. Colwell,et al.  On the Measurement of Niche Breadth and Overlap. , 1971, Ecology.

[15]  J. C. Muñoz-Reinoso.  Vegetation changes and groundwater abstraction in SW Doñana, Spain , 2001 .

[16]  G. Patil,et al.  Diversity as a Concept and its Measurement , 1982 .

[17]  E. Pianka,et al.  Niche overlap and diffuse competition. , 1974, Proceedings of the National Academy of Sciences of the United States of America.

[18]  Yaning Chen,et al.  Indicating appropriate groundwater tables for desert river-bank forest at the Tarim River, Xinjiang, China , 2009, Environmental monitoring and assessment.

[19]  W. Romme,et al.  FIRE AND LANDSCAPE DIVERSITY IN SUBALPINE FORESTS OF YELLOWSTONE NATIONAL PARK , 1982 .

[20]  Yaning Chen,et al.  Physiological response of natural plants to the change of groundwater level in the lower reaches of Tarim River, Xinjiang , 2004 .

[21]  Yaning Chen,et al.  Response of the accumulation of proline in the bodies ofPopulus euphratica to the change of groundwater level at the lower reaches of Tarim River , 2003 .

[22]  C. Simmons,et al.  Spatial relationships between vegetation cover and irrigation-induced groundwater discharge on a semi-arid floodplain, Australia , 2006 .

[23]  Yaning Chen,et al.  Desiccation of the Tarim River, Xinjiang, China, and mitigation strategy , 2011 .

[24]  J. Turner,et al.  Influence of groundwater depth on the seasonal sources of water accessed by Banksia tree species on a shallow, sandy coastal aquifer , 2002, Oecologia.

[25]  Richard Law,et al.  Large niche overlaps among coexisting plant species in a limestone grassland community , 1989 .

[26]  L. Weihong.  The Driving Forces of Environmental Change during the Last 50 Years in the Tarim River Basin , 2006 .

[27]  Francine M. R. Hughes,et al.  Managing river flows to restore floodplain forests , 2005 .

[28]  Yaning Chen,et al.  Physiological response of riparian plants to watering in hyper-arid areas of Tarim River, China , 2007, Frontiers of Biology in China.

[29]  Yaning Chen,et al.  The Natural Vegetation Responses to the Groundwater Change Resulting from Ecological Water Conveyances to the Lower Tarim River , 2007, Environmental monitoring and assessment.

[30]  Yaning Chen,et al.  Analysis on the ecological benefits of the stream water conveyance to the dried-up river of the lower reaches of Tarim River, China , 2004 .

[31]  Yaning Chen,et al.  Degradation of Populus euphratica community in the lower reaches of the Tarim River, Xinjiang, China. , 2005, Journal of environmental sciences.

[32]  F. Bernáldez,et al.  Vegetation of groundwater discharge sites in the Douro basin, central Spain , 1990 .

[33]  Jianhua Xu,et al.  Statistical analysis of groundwater chemistry of the Tarim River lower reaches, Northwest China , 2012, Environmental Earth Sciences.

[34]  Benjamin Smith,et al.  LIFE HISTORY DIFFERENCES AND TREE SPECIES COEXISTENCE IN AN OLD-GROWTH NEW ZEALAND RAIN FOREST , 1998 .

[35]  Zhang Yu-shu.  Desertified Soil Characteristics and Fractal Feature in Lower Reaches of Tarim River , 2004 .

[36]  Yaning Chen,et al.  The threshold of soil moisture and salinity influencing the growth of Populus euphratica and Tamarix ramosissima in the extremely arid region , 2012, Environmental Earth Sciences.

[37]  Yaning Chen,et al.  Ground-water level affects plant species diversity along the lower reaches of the Tarim River, Western China , 2006 .

[38]  R. Mata-González,et al.  Phreatophytic Vegetation and Groundwater Fluctuations: A Review of Current Research and Application of Ecosystem Response Modeling with an Emphasis on Great Basin Vegetation , 2005, Environmental management.

[39]  Fan ZiLi,et al.  Research of Eco-water Table and Rational Depth of Groundwater of Tarim River Drainage Basin , 2004 .

[40]  Some Recent Developments in Plant Community Ecology , 1987 .

[41]  Yaning Chen,et al.  Effect of the ecological water conveyance project on environment in the Lower Tarim River, Xinjiang, China , 2009, Environmental monitoring and assessment.

[42]  S. Hart,et al.  Hydraulic lift: a potentially important ecosystem process. , 1998, Trends in ecology & evolution.

[43]  Chen Yaning,et al.  Utilization of Water Resources and Ecological Protection in the Tarim River , 2003 .

[44]  Fu Ai-hong.  Study on Net Groundwater Recharge after Ecological Water Conveyance in the Lower Reaches of Tarim River , 2009 .

[45]  P. Abrams.  SOME COMMENTS ON MEASURING NICHE OVERLAP , 1980 .

[46]  J. Stromberg,et al.  Importance of low-flow and high-flow characteristics to restoration of riparian vegetation along rivers in arid south-western United States , 2007 .

[47]  W. Qiang,et al.  Physiological response of riparian plants to watering in hyper-arid areas of Tarim River, China , 2007 .

[48]  P. Chesson,et al.  A need for niches? , 1991, Trends in ecology & evolution.

[49]  Zhenghui Xie,et al.  Prediction of water table under stream–aquifer interactions over an arid region , 2009 .

[50]  Song Yudong,et al.  Influence of groundwater level change on vegetation coverage and their spatial variation in arid regions , 2004 .

[51]  J. Stromberg,et al.  Effects of Groundwater Decline on Riparian Vegetation of Semiarid Regions: The San Pedro, Arizona , 1996 .