Analysis Of Forest Canopy Sturcture And Herbaceous Plant Communties In Lingkong Mountain, Shanxi

This study investigates the forest vegetation-environment relationship in Lingkong Mountain of Shanxi, with primary focus on the effects of canopy structure and site on the composition and diversity of herbaceous plant communities on forestfloor. The spatial pattern of vegetation and canopy structure was determined with QuickBird remote sensing imagery analysis, and then the effects of canopy patches on the composition and distribution of herbaceous plant communities on forestfloor were studied by establishing and surveying standard plots within representative forest stands. The purpose of the study was to gain scientific understanding on the controls of distribution and diversity of herbaceous plants on forestfloor under warm temperate climate and to provide some basic guiding principles for devising forest management strategies compromising biodiversity conservation.Firstly, the community characteristics of herbaceous plants on forestfloor were investigated in a typical catchment within the study area-the Xiaoshegou (the little snake creek), by establishing standard plots and surveying plant species. Based on the methods of two-way indicator species analysis (TW1NSPAN), canonical correspondence analysis (CCA), and partitioning of variance of habitat and biotic factors, the relationship between herb-layer plant distribution and canopy structure in the Xiaoshegou was examined. Then at a landscape scale, the community composition, species distribution, and diversity of herbaceous plants on forestfloor were compared among stands of constrasting canopy patch types. The canopy patch types were differeantiated as Pinus tabidifonnis Carr (pine stand), Quercus wutaishanica Mayr (broadleaf stand), and P. tabuliformis-Q. wutaishanica mixture (mixed-wood stand). By incorporating topographic and biotic factors, the effects of canopy structures on herbaceous plant communities were examined with methods of multi-response permutation procedure (MRPP), indicator species analysis (ISA), and CCA ordination.Major results are summarized as follows:1. The spatial heterogeneity of canopy directly determines the composition of herbaceous plant communities; whereas topography exerts an important effect on the distribution of herbaceous plants.2. At small level, forest types, soil fertility and slope position are the most important environmental factors explaining the spatial variations in the occurrence of herbaceous plants on foretfloor. Among the factors affecting distribution of herbaceous plants, habitat conditions in terms of topography and soil fertility explain more variances in the spatial pattern of herbaceous plants than biotic factors in terms of canopy openness and forest types.3. At landscape scale, canopy structure is the most important determinant of community composition and species distribution of the herb-layer. There are distinct differences in herbaceous plant community among forests of the three contrasting canopy patch types. Pinus tabidifonnis stand and P. tabuliformis-Q. wtttaishanica stand support similar herbaceous plant communities and contain the same indicator species; whereas Q. wutaishanica stand differs with other two canopy patch types in herb-layer community. Litter mass, aspect and canopy openness are most important in explaining species composition and diversity of herb-layer at landscape scale.4. Pinus labulifonnis-Q. wutaishanica stand is found to have highest species richness and lowest Whittaker’s measure of inter-site variability in species composition (i.e. β-diversity) in the herb-layer among the three forest patch types, highlighting the ecological significance of the mixed-wood forest in maintaining biodiversity and community stability in warm temperate forest ecosystems.