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.