水源圈研究进展

在干旱、半干旱区草场上，由于饮水的需求导致牲畜经常性地集中在水源点周围，从而使草地生态系统以水源点为中心呈梯度退化，形成水源圈.按照放牧影响程度的大小，以水源点为中心由内向外可将水源圈划分为“牺牲带”、过渡带和自然带3部分，水源圈内的植被、土壤等对放牧的响应也呈梯度变化.由于水源圈内存在着“天然的放牧梯度”，使其成为研究放牧对植被、土壤的影响和自然资源保护及其可持续利用的绝佳场所.本文对水源圈的概念、研究的发展历程和研究方法等进行了综述，并对国内研究现状进行了评述，以促进干旱、半干旱区草场的科学管理和可持续利用.

Research progress on piosphere

On the grassland of arid and semiarid regions, livestock due to its water demand often concentrated at the vicinity of water point. The intensive graz
ing and trampling of the livestock often result in the radial degradation of grassland ecosystem along a gradient from the water point, and the formation of piosphere. According to the impacting degree of the grazing and trampling, piosphere can be divided into three concentric zones, i.e., sacrificial” core, transitional zone, and peripheral zone, radiating outward from the water point. Accordingly, the responses of vegetation and soil within the piosphere also exhibit a radial gradient from the water point to the margin. Piosphere provides an ideal context for the studies on the impact patterns of grazing on vegetation and soil, and the countermeasures for the conservation and sustainable utilization of natural resources in a degrading area because of the existence of an impacting gradient of grazing and trampling from the core to its peripheral zone.  This paper tried to provide a full picture about the concepts, approaches, and research progress of piosphere, aimed to benefit the efficient management and sustainable utilization of natural resources of grassland in arid and semiarid regions.