干旱区生态环境知识资源中心

A study of 26 burnt mulga (Acacia aneura) stands was conducted from 2003 to 2012 in the Gibson Desert and eastern Gascoyne-Murchison region of Western Australia to assess the effect of fire interval on seedling regeneration. Tree-ring analysis and Landsat satellite imagery identified mulga stands with fire intervals ranging from 3 to 52 years. Results show fire-return intervals less than 20 years produce 2-3-year-old seedling regeneration lower than 50% of the original adult stand population (average juvenile-to-adult ratio=0.49). In total, 6 of the 26 stands sampled had reburnt within 3 to 10 years of the previous burn, a consequence of increased plant growth associated with higher rainfall. For all fires, summer fires were larger and more frequent (24 of 35 fires recorded, median fire size=150km(2)) than spring fires (median fire size=91km(2)). This study emphasises the important role of fire in maintaining the diversity and vigour of the mulga-Triodia ecosystem but indicates a minimum fire-return interval of 26 years to maintain mulga populations.