干旱区生态环境知识资源中心

Catastrophic soil erosion has resulted in the desertification of vast areas in Iceland. Barren lands are revegetated on a large scale by aerial broadcasting of commercial grass seed of Festuca rubra cv. Leik (red fescue) and subsequent regular fertilizer application for five years. Vegetation cover following aerial seeding of F. rubra was recorded in three reclaimed sites, which were two, ten and 25 years old, in an inland area in southern Iceland. As a comparison, vegetation cover was also recorded on barren land. Plant succession was inferred from these records. Vegetation cover was recorded using the point-intercept method. Spores of arbuscular mycorrhizae fungi (AMF) were recorded from each site. Barren lands have characteristically low (< 5%) vegetation cover. The highest cover of F. rubra was found two years after revegetation was initiated. Non-dependent AMF forbs also colonized and increased their cover rapidly in the second year due to fertilizer application, but after a decade their cover declined. Ten years after the aerial seeding, F. rubra disappeared and the area was dominated by the native grass Agrostis stolonifera (creeping bent grass). A cover of mosses and plant litter was also recorded on the ten-year-old site. AMF spores were low in all studied sites, and colonization of AMF was only found in the roots of A. stolonifera. After 25 years, it appeared that the cover of native forbs started to increase again and salix bushes were established. Aerial seeding of F. rubra failed to create a long-lasting cover to facilitate natural rapid succession. Alternative revegetation practices, taking into consideration the dynamics of the mutualistic microorganisms (Rhizobium and AMF)/plant association, are suggested for a better and more economic management of reclamation strategies. Copyright (C) 1999 John Wiley & Sons, Ltd.