Effects of Different Human Disturbance on Niche of Dominant Arbor Species in Castanopsis carlesii Community

In 2022,the dominant tree species of the Castanopsis carlesii community were studied under both artificially promoted regeneration（human disturbance treatment） and natural regeneration at the State-owned Forest Farm in Youxi County, central Fujian Province.The Levins and Shannon niche width and Pianka niche overlap methods were used for quantitative analysis of the ecological niche.The results showed that the Castanopsis carlesii exhibited the highest importance value and niche breadth in both artificially promoted regeneration and natural regeneration stands.In naturally regenerated stands, species such as Castanopsis carlesii,Schima superba,Castanopsis eyrei and Machilus velutina showed increased niche breadth values in artificially promoted regeneration stands, with enhanced ecological dominance within the community.Conversely, species like Diospyros morrisiana,Elaeocarpus decipiens experienced reduced niche breadth values, accompanied by weakened resource utilization efficiency and environmental adaptability.The artificially promoted regeneration stands were categorized into three distinct combinations based on changes in niche breadth and total niche overlap values: the niche breadth values and the overall overlap values of Castanopsis carlesii,Schima superba,Machilus velutina,Castanopsis eyrei and other species both increased; the niche breadth values of Cunninghamia lanceolata,Daphniphyllum oldhamii,Castanopsis fargesii and other species increased, while the total overlap values decreased; the niche breadth values of Elaeocarpus decipiens,Elaeocarpus chinensis,Diospyros morrisiana and other species decreased, but their overall overlap values increased.In summary, the overall niche breadth of artificially promoted regeneration forests under human interference was higher than that of natural regeneration forests, indicating stronger resource utilization ability.The ecological niche overlap of the two forest stands was moderate, and the degree of competition between species was basically the same.The selection and allocation of tree species based on ecological niche selection, supplemented by artificial promotion of regeneration measures, is a better choice to achieve the protection of evergreen broad-leaved forests, sustainable forest management, and restoration of forest ecological functions.