Diversity of woodland communities and plant species along an altitudinal gradient in the Guancen Mountains, China.

Study on plant diversity is the base of woodland conservation. The Guancen Mountains are the northern end of Luliang mountain range in North China. Fifty-three quadrats of 10 m × 20 m of woodland communities were randomly established along an altitudinal gradient. Data for species composition and environmental variables were measured and recorded in each quadrat. To investigate the variation of woodland communities, a Two-Way Indicator Species Analysis (TWINSPAN) and a Canonical Correspondence Analysis (CCA) were conducted, while species diversity indices were used to analyse the relationships between species diversity and environmental variables in this study. The results showed that there were eight communities of woodland vegetation; each of them had their own characteristics in composition, structure, and environment. The variation of woodland communities was significantly related to elevation and also related to slope, slope aspect, and litter thickness. The cumulative percentage variance of species-environment relation for the first three CCA axes was 93.5%. Elevation was revealed as the factor which most influenced community distribution and species diversity. Species diversity was negatively correlated with elevation, slope aspect, and litter thickness, but positively with slope. Species richness and heterogeneity increased first and then decreased but evenness decreased significantly with increasing elevation. Species diversity was correlated with slope, slope aspect, and litter thickness.

Effects of tourism and topography on vegetation diversity in the subalpine meadows of the Dongling Mountains of Beijing, China.

Subalpine meadows in the Dongling Mountains (located at E115º26'-115º40', N40º00'-40º05') of Beijing, China are important for tourism and the provision of ecosystem services. However, because of poor management serious degradation has occurred on these subalpine meadows. The aim of this paper is to present a quantitative analysis of effects of tourism disturbance and topography on the status and diversity of montane meadow communities and to provide direction for improved management. Sixty quadrats of 2 × 2 m(2) along 10 transects were set up to collect data on site characteristics and vegetation status. The relationships between community composition and structure, species diversity, and tourism disturbance and topographic variables were analyzed by multivariate methods (TWINSPAN and CCA). The results showed that eight meadow communities were identified by TWINSPAN. Most of them were seriously degraded. The first CCA axis identified an elevation and tourism disturbance intensity gradient, which illustrated that tourism disturbance and elevation were most important factors influencing meadow types, composition and structure. Some resistant species and response species to tourism disturbance were identified and can be used as indicator species of tourism disturbance. Species richness, heterogeneity and evenness were closely related to tourism disturbance and elevation. It is concluded that tourism disturbance must be controlled to enable grassland rehabilitation to occur in the meadows. Measures of effective management of the meadows were discussed.

[Niche analysis of dominant species of forest community in Xiaowutai Mountain, China]. / 小五台山森林群落优势种的生态位分析.

This paper analyzed the niche breadth and niche overlap of dominant species of forest community in Xiaowutai Mountain, and fitted the response patterns of dominant species to the environment gradients by generalized additive models. The results showed that a total of 392 species of vascular plants, belonging to 222 genera, 75 families were recorded in 148 quadrats. A total of 36 dominant species were selected from the tree layer, shrub layer and herb layer by importance va-lues. Betula albosinensis, Betula platyphylla, Larix principis-rupprechtii, Pinus tabuliformis at the tree layer, Spiraea pubescens, Abelia biflora, Rosa bella, Corylus mandshurica at the shrub layer, Carex breviculmis, Deyeuxia arundinacea, Sanguisorba officinalis, Carex siderosticta at the herb la-yer had higher niche breadth, and these species had greater competitiveness and stronger environmental adaptability. In the same layer, niche overlap index was high indicating that species had similar habitats, and there was competitive relationship between them. Although Acer momo and Quercus wutaishanica had high niche overlap, their competition was not strong in the condition of rich resources. There was niche overlap between B. platyphylla and a variety of mixed tree species including A. momo, Q. wutaishanica, Sorbus alnifolia, and limited resources leaded to strong competition in these communities. The adaptability of each species to environmental factors was diffe-rent. The response of most dominant species to altitude showed a single peak curve, and they distri-buted within a certain altitude range. The response of some dominant species to altitude was linearly increased or decreased, and concentrated at high altitudes or low altitudes. The response of dominant species to slope position was similar to altitude. The dominant species showed a linear change along the slope, showed significantly positive correlation with soil temperature, and showed the cha-racteristics of shade-requiring or sunny-requiring. The response of B. albosinensis, A. biflora, H. bretschneideri, C. breviculmis, C. dahurica to litter layer thickness and soil thickness showed linearly increased. The response of L. principis-rupprechtii, B. albosinensis, P. fruticosa, D. arundinacea to soil moisture showed linearly increased, while linearly decreased to soil electrical conductivity. Most dominant species to soil pH and environmental disturbance showed a single peak curve, and the others showed linearly decreased.

Relationship between tourism development and vegetated landscapes in Luya Mountain Nature Reserve, Shanxi, China.

The relationship between tourism development and vegetated landscapes is analyzed for the Luya Mountain Nature Reserve (LMNR), Shanxi, China, in this study. Indices such as Sensitive Level (SL), Landscape Importance Value (LIV), information index of biodiversity (H'), Shade-tolerant Species Proportion (SSP), and Tourism Influencing Index (TII) are used to characterize vegetated landscapes, the impact of tourism, and their relationship. Their relationship is studied by Two-Way Indicator Species Analysis (TWINSPAN) and Detrended Correspondence Analysis (DCA). TWINSPAN gives correct and rapid partition to the classification, and DCA ordination shows the changing tendency of all vegetation types based on tourism development. These results reflect the ecological relationship between tourism development and vegetated landscapes. In Luya Mountain Nature Reserve, most plant communities are in good or medium condition, which shows that these vegetated landscapes can support more tourism. However, the occurrence of the bad condition shows that there is a severe contradiction between tourism development and vegetated landscapes.