宁夏沿黄城市带湿地景观格局演变特征及驱动力

湿地作为全球生产力最高的生态系统之一,具有水净化、气候调节、碳汇等多种功能,但由于人类社会发展的胁迫和自然条件的改变,湿地流失尤为严重。为探究沿黄湿地景观格局演变规律,了解湿地资源的现状和动态变化,本研究以2000、2009、2018年3个时期Landsat卫星影像为数据源,选用景观指数、地理探测器等方法定量分析2000—2018年间宁夏沿黄城市带湿地景观格局演变特征及驱动力。结果表明: 2000—2018年,宁夏沿黄城市带湿地面积呈先增后减的趋势,湿地面积在研究前期增加了52.2 km²,增长率为8.2%,后期减少了26.8 km²,减少率为3.9%。湿地主要转出为建设用地和未利用地,转出面积分别为166.7、158.4 km²;新增湿地主要由未利用地和林草地转入,转入面积为543.1 km²。城市带湿地景观的破碎化程度呈上升趋势,但各类湿地均衡分布的态势逐渐增强,景观多样性也不断增加,景观优势种类逐渐弱化。自然要素和社会经济要素共同影响城市带湿地景观格局演变,其中,社会经济要素中的人口因素影响最显著,自然要素中的降水量、气温驱动作用明显,其他驱动力因子相对较弱但也不容忽视。

Characteristics and driving forces of wetland landscape pattern evolution of the city belt along the Yellow River in Ningxia,China

Wetlands are one of the most productive ecosystems in the world, with functions of water purification, climate regulation, and carbon sinks. Due to the stresses caused by human social development and changes of natural conditions, wetlands have been seriously damaged. We examined the evolutionary law of landscape pattern of wetland along the Yellow River, and acquainted the current situation of wetland resources and dynamic change. Based on satellite images of year 2000, 2009, and 2018 from Landsat, we used landscape indices and geographic detectors to quantitatively analyze the characteristics and driving forces of wetland landscape pattern evolution of the city belt along the Yellow River in Ningxia from 2000 to 2018. The results showed that the wetland area of the city belt along the Yellow River in Ningxia enlarged first and then decreased from 2000 to 2018. The wetland area increased by 52.2 km² in the early stage of the study with an increasing rate of 8.2%, and decreased by 26.8 km² with a reduction rate of 3.9% in the later stage. The wetland was mainly transformed to construction land and unused land, with transfer out area being 166.7 and 158.4 km² respectively. New wetland was mainly transformed from unused land, forest, and grassland, with an area of 543.1 km². The fragmentation degree of wetland landscape in city belt was increasing, the balanced distribution of all kinds of wetlands was gradually strengthened, the landscape diversity was increasing, and the dominant landscape types were gradually weakening. Natural factors and socio-economic factors jointly affected the evolution of wetland landscape pattern in city belt. Among all socio-economic factors population was the most important one. Among natural factors, precipitation and temperature were important. Other driving factors were relatively weak, but could not be ignored.