浙江天童常绿阔叶林林冠结构与群落物种组成的关系

The forest canopy structure can change the microclimate conditions under the forest and may form a spatial structure independent of the ground habitat, thus affecting the differences in community species composition. This study used airborne LiDAR to obtain high-precision canopy structure information of a 20 hm² evergreen broad-leaved forest plot in Tiantong, Zhejiang, and preliminarily explored the relationship between the canopy structure and the differences in community species composition. The results showed that: (1) When the canopy structure was not considered, the spatial structure independent of the ground habitat was an important influencing factor for the differences in community species composition in the Tiantong plot. At the quadrat scales of 100 m², 400 m², and 2,500 m², the interpretation rates for the differences in community species composition were 25.2%, 28.1%, and 8.0%, respectively. (2) After considering the canopy structure, the canopy structure reduced the interpretation rate of the spatial structure independent of the ground habitat for the differences in community species composition by about 1/3 (26.2% - 36.0%). (3) Among the canopy structure factors, the canopy height had the greatest impact on the differences in community species composition, followed by the internal structure of the canopy; as the quadrat scale increased, the impact of the canopy height on the differences in community species composition decreased, and the impact of the internal structure of the canopy gradually increased. The results of this study proved that the canopy structure is the main driving factor for the spatial structure independent of the ground habitat and has an important role that cannot be ignored in the differences in species composition of the Tiantong plant community. These results clarified the importance of the canopy height and internal structure among the canopy structure factors.

森林林冠结构能改变林下微气候条件,可能会形成独立于地面生境的空间结构,进而影响群落物种组成差异。该研究利用机载激光雷达获取浙江天童20 hm~2常绿阔叶林样地的高精度林冠结构信息,初步探讨了林冠结构与群落物种组成差异的关系,结果表明:(1)未考虑林冠结构时,独立于地面生境的空间结构是天童样地群落物种组成差异的重要影响因子,在100 m~2、400 m~2、2 500 m~2样方尺度上,其对群落物种组成差异的解释率分别为25.2%、28.1%、8.0%。(2)考虑林冠结构后,林冠结构使独立于地面生境的空间结构对群落物种组成差异的解释率降低了约1/3 (26.2%-36.0%)。(3)林冠结构因子中,林冠高度对群落物种组成差异影响最大,其次为林冠内部结构;随样方尺度增大,林冠高度对群落物种组成差异的影响降低,林冠内部结构的影响逐渐增加。该研究结果证明了林冠结构是独立于地面生境的空间结构的主要驱动因子,对天童植物群落物种组成差异具有不可忽视的重要作用。这些结果明晰了林冠结构因子中林冠高度和内部结构的重要性。