关键词: 圆叶乌桕, 蒸腾耗水, 喀斯特, 液流密度, 菜豆树

Abstract: The intervention of human activities on the oasis natural environment has caused a series of ecological and environmental problems. Combined with fieldwork verification, distribution of the oasis in Ganzhou District was extracted by 13 images which were acquired between 1963 and 2009 in this paper. To get the temporal and spatial change of the oasis, the single dynamic degree and bidirectional dynamic degree of the oasis were calculated. Additionally, 13 vector data about the distribution of the oasis were overlaid and landscape indices of oasis were analyzed successively. The development of oasis in Ganzhou District showed a trend of expansion in recent 50 years. Taking the year 1986 as a cutoff point, oasis development could be divided into two stages which were “wave expansion” in the early stage and “stable expansion” in the late stage. The main phenomenon of oasis change showed body stability and peripheral expansion; the secondary phenomenon was internal partial withdrawal and scattered wave. The stable oases were mainly distributed along the Heihe River and around the residential areas of the towns, while oases in fluctuation and atrophy were distributed at the periphery of stable oasis.

Key words: Karst, Radermachera sinica, Triadica rotundifolia, sap flow density, transpiration water consumption.