飞播马尾松林林下植被盖度与环境因子的关系

Relationships between understory vegetation coverage and environmental factors in Pinus massoniana plantations from aerial seeding

采用主成分分析、冗余分析和方差分解法研究飞播马尾松林林下植被盖度与环境因子的关系.结果表明:选取的环境因子共解释飞播马尾松林林下植被盖度信息的74.2%.在低海拔处,林分因子是影响林下植被盖度的主要因素.林分因子、土壤因子及地形因子对林下植被盖度的解释率分别为55.0%(包含29.1%的单独解释率和25.9%的交互作用)、38.9%(包含12.1%的单独解释率和26.8%的交互作用)和9.0%(包含5.6%的单独解释率和3.4%的交互作用).平均胸径和郁闭度对苔藓类、禾本类和灌木类盖度影响程度较大,且呈显著正相关,芒萁类盖度与非毛管孔隙度和土壤含水量呈显著正相关,与平均胸径、郁闭度、土壤养分及酶活性呈显著负相关.禾本类盖度、苔藓类盖度以及灌木类盖度三者紧密联系,相互促进,而芒萁类盖度与这3类林下植被盖度呈显著负相关.

The relationships between understory vegetation coverage and environmental factors in Pinus massoniana plantations from aerial seeding were studied by using principal component analy- sis, redundancy analysis and variation partitioning. The selected environmental factors in total ex- plained 74.2% variation of the understory vegetation coverage. At low altitude, stand characteristics were the key factor to influence the understory vegetation coverage. Stand characteristics, soil prop- erty and topographic factor were respectively explained 55.0% （including 29.1% for separateness and 25.9% for interaction with other factors）, 38.9% （including 12.1% for separateness and 26.8% for interaction with other factors） and 9.0% （including 5.6% for separateness and 3.4% for interaction with other factors） of the total variation. Average diameter at breast height and canopy density affected mostly and positively correlated with the coverage of bryophyta, graminoid and shurb groups at significant level. Noncapillary porosity and soil water content showed a highly signi- ficant positive correlation to dicranopteris coverage, whereas average diameter at breast height, can- opy density, soil nutrients and enzyme activity significantly negatively correlated with it. The cover- age of graminoid, bryophyta and shurb groups showed the positive correlations, which indicated the three groups could promote each other, while the dicranopteris coverage had significant negative correlation with the three groups mentioned above.