基于生态水文最优性理论的河西内陆河流域植被覆盖模拟

Simulation of vegetation cover in the inland river basin of Hexi based on the theory of ecohydrological optimality

在生态恢复过程中,生态系统中植被所处状态对于生态平衡是否可持续至关重要,本研究以河西内陆河流域2000-2020年生长季气象和植被数据为基础,应用Eagleson生态水文最优性理论,模拟流域内生态水文平衡状态下的最优植被覆盖度Meq,植被覆盖度恢复阈值与当前现状植被覆盖度的差值即为植被恢复潜力。结果表明:1)模拟的多年平均最优植被覆盖度Meq与多年生长季平均实际植被覆盖度M的变化一致,但过渡更加平稳,呈现从东南向西北递减的趋势,流域内多年生长季平均实际植被覆盖度为0.163,模拟的多年平均最优植被覆盖度为0.166。2)流域内平均恢复潜力为0.003,植被覆盖度仍具有恢复潜力的面积占比为62.76%,分布在流域北部地区,3个流域内平均植被恢复潜力为石羊河流域>黑河流域>疏勒河流域。3)河西内陆河流域植被恢复潜力与区域干旱指数密切相关。森林的平均植被恢复潜力随着干旱等级增加呈减小的变化特征;而灌木植被覆盖度超过恢复潜力的程度随干旱指数增加呈先加剧后减轻的变化特征。

In the process of ecological restoration,the state of vegetation within the ecosystem system is crucial for the sustainability of ecological balance.This study utilizes meteorological and vegetation data during the growing seasons from 2000 to 2020 in the Hexi Inland River Basin as a basis.It applies the Eagleson’s ecological hydrological optimality theory to simulate the optimal vegetation cover(Meq)under the ecological hydrological balance in the basin.The difference between the vegetation cover recovery threshold and the current vegetation cover represents the potential for vegetation restoration.The results show that:1)The simulated average multi-year Meq is consistent with the multi-year growing season average actual vegetation cover M,but the transition is smoother,showing a decreasing trend from southeast to northwest.The multi-year average actual vegetation cover in the basin is 0.163,and the simulated average multi-year optimal vegetation cover is 0.166.2)The basin’s average restoration potential is 0.003 and the area with vegetation cover still had restoration potential accounted for 62.76%,primarily situated in the northern region of the basin.The average vegetation restoration potential across the three basins follows the order:Shiyang River Basin>Heihe River Basin>Shule River Basin.3)The potential for vegetation recovery in the Hexi Inland River Basin is closely related to the regional drought index.For the forest,the average potential for vegetation recovery decreases with rising drought degree,while the degree to which shrub vegetation cover exceeds the restoration potential initially worsens and then lessens as the drought index increases.