论文部分内容阅读
云南松(Pinus yunnanensis)林是我国西南地区最为广布的针叶林。火烧是云南松林常见的一种自然(或人为)干扰,但对云南松林火后更新群落的物种多样性特征很少研究。该研究以云南禄丰县勤丰镇2013年“4.13”火灾后云南松混交林火烧迹地更新早期群落草本层为研究对象,设置了47条1 000 m2样带进行群落和环境因子调查,探讨火烧后更新早期群落草本层的物种构成与丰富度的空间格局及其影响因素。结果表明:火后更新草本层按物种构成可分为4个群落类型;草本层物种丰富度受地形和火前群落冠层的影响显著,与立木生物量和地形坡度正相关,而与坡位和海拔负相关,但与火烧强度没有显著的相关性。样带内草本群落β多样性与火前立木胸面积及火烧强度显著正相关,而与海拔和坡位负相关。总体上,生境地形特征、火前冠层和火烧强度构成了火烧后早期群落草本层物种构成与丰富度变化的主要控制因子。此外,一年生和多年生草本物种的更新格局及其对环境的响应存在显著差异。
Pinus yunnanensis forest is the most widely distributed coniferous forest in southwest China. Fire is a kind of natural (or man-made) disturbance common in Pinus yunnanensis forest. However, the characteristics of species diversity in Pinus yunnanensis forest after fire are rarely studied. In this study, 47 grassland samples of 1 000 m 2 were set up for investigation of the regeneration of the early-stage herb layer of the Pinus yunnanensis mixed forest after the “4.13” fire in Qinfeng Town, Lufeng County, Yunnan Province, China Spatial pattern and influencing factors of species composition and abundance of early herb community after fire burning. The results showed that the herbaceous layer could be divided into four community types according to the species composition. The species richness of the herb layer was significantly affected by the topography and canopy fire crown community, positively correlated with the stand biomass and terrain slope, Negatively correlated with altitude, but not with fire intensity. The β diversity of herbaceous communities in sample zone was significantly and positively correlated with the area of chestnuts and the burning intensity of firewood, but negatively with altitude and slope position. In general, the habitat topography, pre-fire canopy and fire intensity constitute the main controlling factors for the composition and richness of species in the early herb layer after fire. In addition, there are significant differences in the updated pattern of annual and perennial herbaceous species and their response to the environment.