山地视觉景观的GIS评价--以广东南昆山国家森林公园为例

视觉景观评价是指某一特定区域具有视觉价值的景观的量化评价。山地是旅游开发的重要区域,山地景观是山地资源价值和山地生态环境的重要体现之一。以广东南昆山为例,将视野总面积、水域空阔度、景观层作为七仙湖环湖地区视觉景观评价的三大因子。以基础地理数据结合DEM作为数据基础,借助ArcGIS软件作为具体实现平台,设计景观层分析和视通性分析模型,对最佳坡度、最佳坡向、水文、交通条件叠加分析后过滤的62个样地进行视觉景观定量分析,确定评价标准,最后得到8号、23号、50号、55号样地较其他样地在整体视野\,能见水域开阔和景观层次有明显优势。以此验证了将GIS空间分析技术应用于视觉景观评价的可行性,并为旅游观景点与度假村开发提供了科学依据。     

江西三清山优势种群钩锥-山蜡梅群落研究

对江西省三清山钩锥-山蜡梅群落进行了调查和分析.结果表明:(1)群落共有种子植物40科56属81种;其中热带属占63.04%,温带成分占36.96%.(2)群落多样性指数D=0.85,H′=2.77,PIE=0.85,Jsw=0.68,Jsi=0.86,Ea=0.37.(3)群落优势科组成主要为壳斗科、蜡梅科、樟科,而...     

江西省种子植物区系新资料

报道了江西省植物分布新记录3种,均发现于井冈山地区,分别为：肾萼金腰Chrysosplenium delavayi Franch.、圆苞山罗花Melampyrum laxum Miq.和窄叶马铃苣苔Oreocharis argyreia Chun ex K. Y. Pan var. angustifolia K. Y. Pan。     

Molecular phylogeny of Tornier's cat snake (Crotaphopeltis tornieri), endemic to East African mountain forests: biogeography, vicariance events and problematic species boundaries

Five isolated populations of the East African snake species Crotaphopeltis tornieri were investigated using mitochondrial sequence data from the genes cytochrome B and NADH2. The congeneric species Crotaphopeltis hotamboeia and three species of the closely related genera Dipsadoboa were used as outgroups. The results were analysed using unweighted parsimony and the reconstructed phylogeny revealed four well-defined evolutionarily significant units. Very high levels of genetic diversity was observed. The highest levels of divergence was observed between specimens from Mount Rungwe and the remaining populations. A similar pattern but with much lower divergence levels has been observed for the bird species Andropadus masukuensis . Together they indicate that Mt Rungwe is an important area for future conservation efforts. In the analysis of the combined data set C. tornieri appear as non-monophyletic with C. hotamboeia being the sister group to all C. tornieri populations except those on Mt Rungwe. The validity of C. tornieri and C. hotamboeia as species was thereby questioned by the data. However, the support for this is very weak and no nomenclatural consequences are suggested at present.     

Variations in the reproductive cycle of Bornean montane tree species along elevational gradients on ultrabasic and non-ultrabasic soils

Although lowland tree species in the ever-wet regions of Southeast Asia are characterized by the supra-annual cycle of reproduction, the reproductive phenology of montane tree species remains poorly understood. In this study, we investigated the reproductive phenology of montane tree species using litter samples that were collected every 2 weeks from six rainforest sites, consisting of three elevations (1700, 2700, and 3100 m), on Mount Kinabalu, Borneo. At each elevation, one site was on infertile ultrabasic soil and one was on relatively fertile non-ultrabasic soil. We used a composite sample from 10 or 20 litter traps per site and sorted it by species. Therefore, the obtained data captured reproductive phenology in the population of each species rather than in an individual tree. Ten-year time series of flower and fruit litterfall were obtained for 30 and 39 tree species, respectively. Fourier analysis was used to identify the dominant cycle of each time series. The most abundant cycle across species was supra-annual, followed by sub-annual, and annual cycles. Many species at higher elevations showed supra-annual cycles of flower litterfall, whereas species in the 1700 m sites often showed annual or sub-annual cycles regardless of soil types. No systematic differences were found among sites for fruit litterfall. Mechanisms underlying these elevational patterns in reproductive cycle remain unclear but may include more severe El Niño droughts, lower primary productivity, lower soil fertility, and the absence of some sub-annually or annually reproducing families at higher elevations.     

Vegetation recovery patterns in early volcanic succession

Permanently plots were monitored from 1983 to the present on Mount Usu after the eruptions of 1977–78 which destroyed the pre-eruption vegetation by 1–3 m thick accumulations of ash and pumice in order to clarify the processes and mechanisms of succession. Until now, 163 species were recorded in the summit area. Most of these species were derived from vegetative reproduction throughout the volcanic deposits. Vegetative reproduction plays a major role on increases in cover. Although long-distance seed-dispersal species could immigrate to the crater basin, their cover increase was slow. Seedbank species only established in gullies where the original topsoil was exposed by erosion. Most annuais were supplied by the seedbank in the original topsoil and woody species originated via immigration, suggesting that the source greatly determines the species composition of establishing vegetation. Annual seedlings showed low survival, while overwintering perennial seedlings steadily established. Ground surface movements strongly restricted increases in plant cover and the distance from source vegetation was the principal determinant of plant density. Due to differences in disturbance intensity, successional rates were higher in the stable substrates outside gullies and lower on the exposed original topsoil in some gullies. Recipient of the Botanical Society Award of Young Scientists, 1994     

The role of mycorrhizal fungi and microsites in primary succession on Mount St. Helens

This study was designed to examine the role of vesicular-arbuscular mycorrhizae (VAM) and microsites on the growth of pioneer species. Flat, rill, near-rock, and dead lupine microsites were created in plots in barren areas of the Pumice Plain of Mount St. Helens. VAM propagules were added to the soil in half of the plots. Six pioneer species were planted into both VAM and non-VAM inoculated microsites. Plants in dead lupine microsites were greater in biomass than those in flat, rill, and near-rock microsites. Significant effects of VAM on plant biomass did not occur. Microsites continue to be important to plant colonization on the Pumice Plain, but VAM do not yet appear to play an important role. This may be due to limited nutrient availability and the facultatively mycotrophic nature of the colonizing plant species. It is unlikely that VAM play an important role in successional processes in newly emplaced nutrient-poor surfaces.     

Determinants of diversity in afrotropical herbivorous insects (Lepidoptera: Geometridae): plant diversity,vegetation structure or abiotic factors?

Aim This study was conducted to investigate the potential of predicting alpha diversity and turnover rates of a highly diverse herbivorous insect family (Geometridae) based on vascular plant species richness and vegetation structure. Location The study was carried out on the south‐western slopes of Mount Kilimanjaro within a wide range of habitats between 1200 and 3150 m elevation. Methods The floristic and structural composition of the vegetation was recorded at 48 plots of 400 m². Geometrid moths were sampled manually at light sources located at the plot centres. Principal components analysis, redundancy analysis and multiple linear regression were used to explore how alpha diversity and species turnover of geometrid moths are related to vegetation structure and plant species richness. Results Alpha diversity of geometrid moths was significantly correlated with species diversity patterns in the most common vascular plant families (R² = 0.49) and with plant structural parameters (R² = 0.22), but not with overall floristic diversity. Species turnover of geometrid moths was strongly linked to diversity changes in a range of plant families (40% explained variance), less strongly to changes in vegetation physiognomy (25%), and only weakly to overall floristic diversity (5%). Changes in elevation were a better predictor of both alpha diversity and species turnover of geometrid moths than any principal component extracted from the vegetation data. Main conclusions Vegetation composition, diversity and structure all showed significant correlations with the diversity and species composition of geometrid moth assemblages. Nevertheless, in most cases relationships were indirect, via environmental parameters such as temperature and humidity, which influenced both vegetation and moth fauna. Possible direct links between geometrid diversity and potential food plants were much weaker. The lack of a significant correlation between overall plant species richness and geometrid diversity indicates that tropical geometrid moths may not be very selective in their food plant choice. Accordingly, a clear correlation between floral diversity and herbivore species richness must be regarded as overly simplistic, and the diversity of vascular plants cannot universally be used as a suitable biodiversity indicator for diverse insect taxa at higher trophic levels.