| Nature forests were cut down over-excessively, a large number of man-made forests were existed, ecological functions of forests were decreasing greatly, thus resulting from a series of serious ecological problems.Gap played an important role in population dynamic and succession in forest ecology system.Not only utilizing timber but also remaining and promoting forest ecological functions, which were the targets what learners persisted on.According to this, Middle Europe Countries promoted "Nature-ApproximatingForest", but they did not pay attention to gap regeneration.The present situation of gap research of the world was summarized, the niche and interspecific competition of main tree species in slope position , in slope shape, in altitude or in terrain resource space(including slope position, slope shape, altitude resource space of the three dimensions) of gaps and non-gaps were not reported.In different resource spaces, regardless of consideration of resource utilization ratio or not, the species which had a niche breadth value higher than mean niche breadth value belonged to broader niche breadth species; the species which had a niche breadth value lower than mean niche breadth value, belonged to narrower niche breadth species.The species counterpart which had a niche overlap value higher than mean niche overlap value belonged to higher niche overlap species counterpart! the species counterpart which had a niche overlap value lower than mean niche overlap value belonged to lower niche overlap species counterpart.According to these, this paper analyzed the niche characteristic of Castanopsis carlesii , Castanopsis nigrescens, Castanopsis fargesii and other nine main tree species population in these resource spaces in nature Castanopsis species stand in Wuyi Mountain by using different niche breadth and niche overlap formulas.The species competition potential was promoted to adjust the niche overlap to get interspecific competition coefficient so this paper analyzed the interspecific competition of three main tree species of Castanopsis carlesii and Castanopsis nigrescens and Castanopsis fargesii in these resource spaces by using Lotka-Volterra competition model, the results showed that:Different species had different ecological characteristics, considered resource utilization ratio, there was a large influence on niche breadth metrics.Whether Consideration resource utilization ratio or not, there were no changes of the niche breadth types of the same species in slope position , slope shape and altitude resource spaces in gaps and in non-gaps, but there were a large influence on the niche breadth type of the same species in terrain resource space in gaps and in non-gaps.In different resource space in gaps and in non-gaps, the niche characteristic type of different species and different species counterpart were different.Regardless of consideration of resource utilization ratio or not, the same population has a different niche breadth in different resource spaces between gaps and non-gaps also.Among the 12 main tree species populations, without consideration of resource availability, there were 8, 8, 8, 5 species had a higher niche breadth value than the mean niche breadth value in slope position, slope shape, altitude and terrain resource space of gaps respectively, and there were 7, 9,8,6 species had a higher niche breadth value than the mean niche breadth value in slope position, slope shape, altitude and terrain resource space of non-gaps respectively.With consideration of resource availability, there were 8, 8, 8, 7 species had a higher niche breadth value than the mean niche breadth value in slope position, slope shape, altitude and terrain resource space of gaps respectively, and there were 7, 9, 8, 7 species had a higher niche breadth value than the mean niche breadth value in slopeposition, slope shape, altitude and terrain resource space of non-gaps respectively. Among 66 species counterparts, there were 35, 39, 33, 31 species counterparts had a higher niche overlap val... |
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