关帝山云杉次生林不同生活型物种与生境相关性

Correlation between different life-form species and habitat in secondary Picea forest

以关帝山庞泉沟自然保护区4 hm^2云杉次生林固定监测样地调查数据为基础,采用方差分解(RDA)分析了地形和土壤与不同生活型物种分布的关系,并对两生境因子进行主成分分析(PCA),通过广义可加模型(GAM)拟合了乔木、小乔木、灌木中优势物种分布与主成分分析中各主分量的关系。结果表明:(1)地形和土壤共解释了乔木、小乔木、灌木分布的53.34%、55.65%和45.83%,其中地形因子独立解释了8.36%、5.06%和5.48%,土壤因子独立解释了31.12%、44.22%和32.04%,两因子共同解释的部分为13.86%、6.37%和8.31%;(2)对13个生境指标进行主成分分析表明,前4个主分量分别代表了38.76%、25.73%、19.41%和8.93%,累计贡献率达92.56%;(3)GAM拟合结果显示,不同生活型及同一生活型不同物种分布与生境4个主分量相关程度均不同。模型可解释的偏差分别为:乔木层介于0.76%~29.00%,小乔木层介于0~20.30%,灌木层介于0.10%~23.50%。各物种及各生活型物种普遍与PC1相关程度较大,海拔、坡向、有效K、有效N、有效Mg对物种分布具有重要作用。研究结果表明,地形、土壤等生境因子对不同物种及不同生活型物种分布的影响有差异,这种差异有利于关帝山云杉次生林物种共存和多样性维持。

Based on the survey data of a 4-hm2 fixed monitoring plot in Pangquangou Nature Re- serve on Guandi Mountain, we analyzed correlation between different life-form species distribution and two habitat factors-terrain and soil in a secondary Picea forest using variance decomposi- tion （RDA） and fitted relationships between the dominant species of trees, small trees and shrubs and principal components of habitat factors by generalized additive model （GAM）. The results showed that： （1） Terrain and soil together explained the distribution of trees （53.34%）, small trees （55.65%） and shrubs （45.83%）, including an independent explanation by terrain （8.36%, 5.06% and 5.48%, respectively） , an independent explanation by soil （ 31.12%, 44.22% and 32.04%, respectively）, and a joint part explanation （ 13.86%, 6.37% and 8.31%, respectively） ; （2） The principal component analysis of 13 habitat indexes showed that the first four principal components represented 38.76%, 25.73%, 19.41% and 8.93%, respectively, with a cumulative contribution rate of 92.83%; （3） For different species and life-form species, the degree of correlation between their distribution and the four principal components was differ- ent by GAM fitting. The deviations explained by the model were 0.76%-29.00% for tree layer, 0-20.30% for small tree layer and 0.10%-23.50% for shrub layer. Each species and life form were better associated with PC1, and altitude, aspect, available K, N and Mg played an impor- tant role in species distribution. The result indicated that the effects of habitat factors such as ter- rain and soil on the different life-form species distribution were different, which promoted the coex- istence and biodiversity maintaining of species in the secondary Picea forest on Guandi Mountain.