卧龙自然保护区针阔混交林林隙更新规律

GAP-PHASE REGENERATION RULES OF CONIFER-BROADLEAVED MIXED FOREST IN WOLONG NATURE RESERVE, CHINA

卧龙自然保护区五一棚大熊猫野外观测站周围的针阔混交林由于历史原因破坏严重,长期以来自然恢复较差。为调查该区林隙更新的现状及其影响因素,作者采用林隙样线调查方法研究了该区针阔混交林林隙更新规律。结果显示,历史上的自然干扰与人为干扰共同影响着该区林隙更新的格局和特征,林隙天然更新受环境因素制约,更新规律表现为:更新幼苗的种类较形成木的种类丰富,更新乔木幼苗的优势度排序与形成木不同;林隙主要树种的更新受各类环境因子的影响而存在差异,桦木(Betula spp.)更新受地形影响较大,岷江冷杉(Abies faxoniana)受土壤因素影响显著,杜鹃(Rhododendron spp.)更新则受地形因子和林隙形成木的特征影响显著;更新物种的多样性指数均表现出受土壤因子的影响显著。由此推测,林隙大小并非影响该区林隙更新的关键因素,而土壤因素可能是制约优势树种天然更新和更新物种多样性的重要原因之一。

Aims Wolong Nature Reserve is the largest reserve for the endangered wild panda. Owing to historical factors, much of the forest has been disturbed and poorly restored, even in many sections of the core protection area. The relative importance of determinants for species recruitment after disturbance is poorly known. We investigated factors affecting regeneration of conifer-broadleaved mixed forest in forest gaps near Wuyipeng, an observation station for pandas. Methods We examined environmental factors, gap characteristics and recruitment of new individuals in every forest gap along three line transects and analyzed the data using principal component analysis and correlation analysis in SPSS. Important findings A range of natural and human disturbances influenced the pattern and characteristics of forest gaps in this area. Richness was higher for seedlings than for gap makers, but the ranking of species dominance was different between seedlings and gap makers. The establishment success of dominant species was affected by a variety of factors. For instance, the establishment of Betula spp. was correlated significantly with topographic factors, while that of Abies faxoniana was affected heavily by soil characteristics and that of Rhododendron spp. was correlated significantly with topographic factors and gap-maker characteristics. Moreover, all biodiversity indexes of regenerating seedlings were significantly correlated to principal components mostly reflecting soil characteristics. Therefore, soil characteristics appear to be the most important factor influencing regeneration of dominant species and seedling richness following gap disturbance.