干旱区生态环境知识资源中心

Spatial self-organisation of plants and soils is a typical feature of many systems. Different mechanisms have been proposed to explain self-organised patterns, including scale-dependent feedbacks and disturbance recovery mechanisms. In semi-arid systems, there is limited evidence for the spatial self-organisation of leaf litter despite its obvious presence within self-organised vegetation patches. Here we provide field-based evidence for the spatial self-organisation of surface litter. We measured the cover, size distribution and spatial arrangement of perennial vegetation patches and surface litter patches in four vegetation communities in a semi-arid woodland, one of which had been cleared of trees 50 years previously. The effects of tree removal were still evident 50 years after clearing, with greater perennial patch cover and greater variability in surface litter arrangement in the cleared community than the uncleared analogue. Across all communities, we detected a high correlation between perennial patch cover and litter cover. We found no evidence to support scale-dependent feedbacks occurring between litter and perennial patches, with little relationship between perennial patch size and the strength of its association with litter. The distribution of litter patch sizes was consistent with a truncated power law relationship, suggesting that disturbance-recovery mechanisms may play an important role in the spatial self-organisation of litter, particularly through large-scale processes such as wind disturbance.