陕北榆林地区植被好转背景下面临的生态环境新挑战

Ecological Risk of Yulin Area in Northern Shaanxi Under the Condition of Vegetation Coverage Improving

近几十年来,随着退耕还林还草等政策的实施,榆林地区植被覆盖度明显提高,生态环境明显好转。但与此同时,河流流量减少,地下水位下降等问题也逐渐凸显,对其进行梳理总结并提出针对性的对策建议对榆林地区可持续发展具有重要意义。笔者在充分收集前人资料的基础上,全面梳理了榆林地区近年来出现的各种问题,并分析了可能的原因,最后提出对策建议。通过研究发现,近20年以来榆林地区植被指数呈现明显增加的趋势,林草地面积大幅度增加,荒漠化土地面积显著减少。同时,榆林地区较大的河流径流量近50年来普遍减少,尤其以无定河、秃尾河、窟野河最为明显。区域地下水位普遍下降,降幅2~10 m不等。近年来,在西北部毛乌素沙地,出现了大规模开垦耕地的现象。针对前述的问题,建议榆林地区坚决落实以水定产的政策,加强区内水资源优化配置,加大矿井水和黄河水的利用,以灌木林和草本为主进行植被恢复,加强耕地开垦区地下水位和土地沙化的监测。研究榆林地区在新时期出现的生态环境问题及对策建议对于黄河中游生态脆弱区的资源型城市的可持续发展有一定的借鉴意义。

In recent decades,with the mega-eco-environmental projects,such as“Grain for Green Project”performed,the vegetation coverage in Yulin area has increased notably and the ecological environment has improved significantly.At the same time,the river discharge decreased,the groundwater level dropped,has become more prominent.Summarize these possible risks and put forward some pertinence countermeasures are of great significance for the sustainable development of Yulin area.Based on existing data,the article sort out various problems that occurred in recent years in Yulin area.And then analyzed the possible reasons,and finally put forward some suggestions.The results show that the average annual NDVI of Yulin City increased obviously,grassland and forest increased rapidly,and the desertification land reduced clearly in last 20 years.But in the mean time,the discharge of larger rivers in Yulin area has decreased obviously in the past 50 years,especially the Wuding River,Tuwei River,and Kuye River.The groundwater level in the whole area of Yulin dropped about 2-10 m.In recent years,Yulin City began to reclaim cultivated land in the sandy land on a large scale by using the cropland balance policy.In view of the problems occurred in resent years are mostly related to water,so the Yulin area should resolutely implement the policy of water-based production,strengthen the optimal allocation of water resources,increase the utilization of mine water and the water of Yellow River.Vegetation restoration should mainly dominated by shrubs and herbs.The ecological environment problems occurred in resents years,and countermeasures and suggestions of the Yulin can provide reference materials for the sustainable development of resource-based cities in the ecologically fragile area of the middle reaches of the Yellow River.