芦苇和白刺空间格局对青土湖生态输水的响应

石羊河尾闾湖——青土湖位于腾格里沙漠和巴丹吉林沙漠边缘,是阻隔两大沙漠合围的生态屏障。自2010年开始连续5年向青土湖进行生态输水并形成一定规模的水面,对促进区域植被恢复和保护民勤湖区绿洲具有重要的生态意义。本研究选用2008年、2010年、2011年、2012年、2013年、2014年的高分辨率遥感影像资料同时结合研究区的实地调查资料,对形成人工水面的面积和输水前后的芦苇(Phragmites australis)、白刺(Nitraria tangutorum)群落面积进行了统计分析和对比。结果表明,5年连续输水形成叠加效应,水面面积成倍增加,芦苇相对频度逐年增加和白刺相对频度逐年减少,芦苇群落(Form. P. australis)面积增加了8.43倍,临接水域和水域中的白刺群落(Form. N. tangutorum)消失,白刺面积减少了68.00%。人工输水促进了芦苇群落依水蔓延,镶嵌于水域成片分布;距水面50 m范围的白刺群落由连续成片成点状。输水促进了湿生植物生长,导致荒漠植物种退化。

Response of Form.Phragmites australis and Form.Nitraria tangutorum after ecological water delivery to Qingtu Lake

Qingtu Lake——the tail of Shiyang river, located in the edge of Badain Jaran Desert and Tengger Desert, is an ecological barrier to block two deserts encircling. Since 2010, Qingtu Lake has been delivered into ecological water for five years, and had formed certain scale water, which has ecological significance to promote regional vegetation restoration. In this study, the high resolution remote sensing data from 2008, 2010, 2011, 2012, 2013, and 2014 combining with field survey data were used and statistically analyzed to compare the water area and distribution of Phragmites australis, Nitraria tangutorum communities before and after ecological water delivery. The results showed that the water area doubled because of the additive effect by consecutive five-year water delivery additive effect; Relative frequency of Form. P. australis increased and Form. N. tangutorum communities decreased after water delivery; Area of Form. P. australis increased 8.43 times; Area of Form. N. tangutorum reduced about 68.00%, and Form. N. tangutorum distributed near water and in water disappeared. Water delivery has promoted Form. P. australis spreading by water, and Form. N. tangutorum scattered within 50 m distance to water margin. In conclusion, water delivery to Qingtu Lake promotes wetland plants growing and desert plants degradation.