GEOGRAPHICAL RESEARCH ›› 2010, Vol. 29 ›› Issue (5): 899-908.doi: 10.11821/yj2010050014

• Earth Surface Processes • Previous Articles     Next Articles

easonal landscape pattern change and its driving forces of the Napahai Wetland

HU Jin-ming, LI Jie, DONG Yun-xia, YUAN Han   

  1. Asian International Rivers Center, Yunnan University, Kunming 650091, China
  • Received:2009-09-13 Revised:2010-03-14 Online:2010-05-20 Published:2010-05-20

Abstract:

Seasonal hydro-ecological and landscape change are one of the important characteristics of wetlands within monsoonal climate area. This study selected two phases of high-resolution RS images, i.e., SPOT-5 image in December of 2008 and Landsat ETM+ image in May of 2009, to reveal the seasonal landscape changes within the Napahai Wetland, northwest Yunnan Province. Visual interpretation of the RS images was based on the software of Erdas and Arc-GIS, corrected with the information of regional plant investigation and hydrological survey. Hierarchy of the landscape classification for the Napahai Wetland area included system and subsystem. There are 8 landscape types at system level and 13 landscape subtypes at subsystem level. From December of 2008 to May of 2009, there happened dramatic conversion among different landscape types (subtypes) in the Napahai Wetland area, indicating a significantly seasonal shrinkage of all subtypes of wetlands except the stream. Large area of most wetland subtypes was converted into mesophytic meadow subtype, driven by the significant decrease of seasonal precipitation from December of 2008 to May 2009. Meanwhile, under the influence of regional livestock (especially the crossbred pig) grazing, about 15.74% of the Napahai Wetland area was transformed into destroyed land and the patches of the destroyed land extensively dispersed within the whole Napahai Wetland area. Local livestock grazing had the most direct threat to the Napahai Wetland. For the Napahai Wetland, climate condition in spring and early summer, combined with the local livestock grazing and other human disturbances, has the determinant influences upon the hydro-ecological process and the landscape changes of the wetland. This case study showed coordination between wetland conservation and local livestock, and suitable regional water resource management to mitigate the negative impacts from extremely seasonal climate, will be the key to Napahai Wetland conservation.

Key words: Napahai Wetland, landscape pattern, seasonal change, driving forces