Rainforest In Xishuangbanna Research Articles

Six new species of the genus Opopaea Simon, 1891 from Xishuangbanna Rainforest, southwestern China (Araneae: Oonopidae).

Seven species of the genus Opopaea Simon, 1891 from Xishuangbanna Rainforest, Yunnan, China are recognized, including six new species: Opopaea auriforma sp. nov. (male, female), Opopaea cornuta Yin & Wang, 1984, Opopaea flabellata sp. nov. (female), Opopaea macula sp. nov. (male, female), Opopaea rigidula sp. nov. (male, female), Opopaea semilunata sp. nov. (female), and Opopaea zhengi sp. nov. (male, female). Morphological descriptions and illustrations of all the six new species are given. All the types are deposited in the Institute of Zoology, Chinese Academy of Sciences in Beijing (IZCAS).

Comb-footed spiders (Araneae: Theridiidae) in the tropical rainforest of Xishuangbanna, Southwest China

Comb-footed spiders (Araneae: Theridiidae) in the tropical rainforest of Xishuangbanna, Southwest China

Spider diversity in canopies of Xishuangbanna rainforest (China) indicates an alarming juggernaut effect of rubber plantations

We were interested in how forest type and complexity of vegetation influence the diversity of canopy spiders in the rainforest of Xishuangbanna, southwestern China. We sampled spiders by fogging tree canopies in four replicate sites of five different forest types once in the middle of the rainy season, forest types were tropical seasonal rainforest; monsoon forest; mountain rainforest; Aporusa yunnanensis forest; and rubber plantation. From a total of 20 sites and 1000m2 projected area we collected 4999 adult spiders of 472 species. Vegetational structure (number of plant forms, such as herbs, shrubs, trees, epiphytes and lianas), tree coverage, shrub coverage, grass coverage, tree height and elevation characterize the environmental conditions in different types of forest. Species richness and mean abundance differed significantly between rubber plantations and natural habitats. Rubber plantations harbored only 42.6–50% of the spider species in the natural forests, and 63.8% of the species in the A.yunnanensis forests. Spider guild composition also differed among forest types. Sheet-line weavers dominated the spider assemblages in natural forests with complex vegetational structure, such as tropical seasonal rainforests and monsoon forests. In contrast, cursorial hunters dominated forests with a more simple structure, such as rubber plantations and A.yunnanensis forest. These results show that intensive management practices in rubber plantations decrease the complexity of the vegetation and, so, strongly influence the diversity and composition of canopy spider assemblages. A lower intensity of management and the restoration of native vegetation may help balance the opposing needs of economic development and biodiversity conservation in this region.

Direct effects of litter decomposition on soil dissolved organic carbon and nitrogen in a tropical rainforest

To clarify how litter decomposition processes affect soil dissolved organic carbon (DOC) and soil dissolved nitrogen (DN) dynamics, we conducted a field experiment on leaf litter and collected DOC and DN from the underlying soil in a tropical rainforest in Xishuangbanna, southwest China. Principal components analysis (PCA) showed the first PCA axis (corresponding to degraded litter quantity and quality) explained 61.3% and 71.2% of variation in DOC and DN concentrations, respectively. Stepwise linear regression analysis indicated that litter carbon mass controlled DOC and hemicellulose mass controlled DN concentrations. Litter decomposition was the predominant factor controlling surface-soil DOC and DN dynamics in this tropical rainforest.

Seasonal dynamics in photosynthesis of woody plants at the northern limit of Asian tropics: potential role of fog in maintaining tropical rainforests and agriculture in Southwest China.

The lowland tropical rainforests in Xishuangbanna, Southwest (SW) China, mark the northern limit of Asian tropics. Fog has been hypothesized to play a role in maintaining rainforests and tropical crop production in this region, but the physiological mechanism has not been studied. The goals of this study were to characterize the seasonal dynamics in photosynthesis and to assess the potential for fog to mitigate chilling-induced photodamage for tropical trees and crops in Xishuangbanna. We measured seasonal dynamics in light-saturated net photosynthetic rate (Aa), stomatal conductance (gs), intercellular CO2 concentration, quantum yield of Photosystem II (Fv/Fm) and maximum P700 changes (Pm; indicates the amount of active PSI complex), as well as chilling resistance and fog (light/shading) effects on low temperature-induced decline in Fv/Fm and Pm for native tree and introduced lower latitude tree or woody shrub species grown in a tropical botanical garden. Despite significant decreases in Aa, gs, Pm and Fv/Fm, most species maintained considerably high Aa during the cool season (2.51-14.6 μmol m(-2) s(-1)). Shaded leaves exposed to seasonal low temperatures had higher Fv/Fm than sun-exposed leaves in the cool season. All species could tolerate 1.4 °C in the dark, whereas a combined treatment of low temperature and high light caused a distinctly faster decline in Pm and Fv/Fm compared with low temperature treatment alone. Because fog persistence avoids or shortens the duration of high light condition in the morning when the temperatures are still low, our results provide support for the hypothesis that fog reduces chilling damage to tropical plants in this region and thus plays a role in maintaining tropical rainforests and agriculture in SW China.

Diversity and aboveground biomass of lianas in the tropical seasonal rain forests of Xishuangbanna, SW China

Lianas are important components of tropical forests and have significant impacts on the diversity, structure and dynamics of tropical forests. The present study documented the liana flora in a Chinese tropical region. Species richness, abundance, size-class distribution and spatial patterns of lianas were investigated in three 1-ha plots in tropical seasonal rain forests in Xishuangbanna, SW China. All lianas with > or = 2 cm diameter at breast height (dbh) were measured, tagged and identified. A total of 458 liana stems belonging to 95 species (ranging from 38 to 50 species/ha), 59 genera and 32 families were recorded in the three plots. The most well-represented families were Loganiaceae, Annonceae, Papilionaceae, Apocynaceae and Rhamnaceae. Papilionaceae (14 species recorded) was the most important family in the study forests. The population density, basal area and importance value index (IVI) varied greatly across the three plots. Strychnos cathayensis, Byttneria grandifolia and Bousigonia mekongensis were the dominant species in terms of IVI across the three plots. The mean aboveground biomass of lianas (3 396 kg/ha) accounted for 1.4% of the total community above-ground biomass. The abundance, diversity and biomass of lianas in Xishuangbanna tropical seasonal rain forests are lower than those in tropical moist and wet forests, but higher than those in tropical dry forests. This study provides new data on lianas from a geographical region that has been little-studied. Our findings emphasize that other factors beyond the amount and seasonality of precipitation should be included when considering the liana abundance patterns across scales.

Dry‐season water utilization by trees growing on thin karst soils in a seasonal tropical rainforest of Xishuangbanna, Southwest China

ABSTRACTStable isotopes were used to evaluate water utilization for three tree species (Cleistanthus sumatranus, Lasiococca comberi var. pseudoverticillata and Celtis wightii) growing on karst soils in the seasonal tropical rainforest of Xishuangbanna, Southwest China. The soil on the site is only 40 cm thick but was underlain by thick limestone bedrock with large water storage capacity. Dense radiational fog occurred frequently during the pronounced dry season. Isotope composition of water in xylem, soil and fog were analysed, and soil and stem porous water content were measured concurrently to determine the proportion of water deriving from fog, soil and bedrock by adult trees and seedlings at the peak of the dry season. Results indicated that C. wightii seedlings suffered stronger water stress and greatly relied on available moisture from fog (23.8% on average). This suggests that fog water was an important source for seedling growth during the pronounced dry season. In contrast, adult trees had little or negligible water uptake from fog moisture (3–7% on average) but derived around 63–85% of their water from bedrock sources. Water held within bedrock was essential for meeting plant transpiration requirements over the dry season drought. Copyright © 2013 John Wiley & Sons, Ltd.

4种高大树木的叶片性状及WUE随树高的变化

PDF HTML阅读 XML下载 导出引用 引用提醒 4种高大树木的叶片性状及WUE随树高的变化 DOI: 10.5846/stxb201304020586 作者: 作者单位: 中国林业科学研究院林业研究所,华南农业大学林学院,中国林业科学研究院林业研究所 作者简介: 通讯作者: 中图分类号: Q945.79 基金项目: 教育部博士点基金资助项目(20124404110007);中国林科院林业所所长基金资助项目(RIF2013-08) Changes of leaf traits and WUE with crown height of four tall tree species Author: Affiliation: State Key Laboratory of Tree Genetics and Breeding,Research Institute of Forestry,Chinese Academy of Forest,Beijing,College of Forestry,South China Agricultural University,Guangzhou,State Key Laboratory of Tree Genetics and Breeding,Research Institute of Forestry,Chinese Academy of Forest,Beijing Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为了解西双版纳北热带雨林高大树木树顶叶片性状对通道阻力增长引起的水力限制增强及高光和季节性干旱等气候条件的响应,对该区乔木浆果乌桕(Sapium baccatum Roxb)、思茅木姜子(Litsea pierrei var. szemois liou)、小叶藤黄(Garcinia cowa Roxb)及共生木质藤本黑风藤(Fissisfigma polyanthum (Hook. f. et Thoms.)Merr.)的叶片形态解剖结构、光合色素、水分利用效率(WUE)等随冠层高度的变化及种间差异进行了研究。结果表明:小叶藤黄和思茅木姜子的叶片(310.14、319.73 μm)和角质层(6.06、5.13 μm)都较厚、细胞较大(21.48、27.09 μm),光合色素含量则较低;黑风藤栅栏组织所占的比例最大、光合色素含量也最高,但叶片薄、WUE最低;浆果乌桕的WUE最高。随着冠层高度的增加,4种树木的叶厚、栅栏组织及角质层厚度、LMA、P/S和TPM/LT均增加、细胞变小,其中黑风藤的变幅最大。4树种的叶绿素和类胡萝卜素含量均随冠层的增高而减少,δ13C和WUE则随树冠增高而增大(黑风藤的变幅小于3种乔木);Δ则相反。上述结果表明4种树木冠层上部叶片偏向旱生结构和水分利用效率增加,暗示树顶叶片可能受到了水分胁迫,从而在结构上偏向于减少水分散失、功能上提高对水分的利用效率以适应水分亏缺;同时,随冠层增加光合色素含量减少,暗示其光合碳同化能力也降低。上述结果支持了水力限制假说中由于通道阻力增大引起树顶水力限制增强,大树可能会通过减少光和碳的获得而减慢树高生长的假设。 Abstract:Leaves as the main photosynthetic organs are sensitive to exterior environments. Generally the structure and physiological characteristics of leaves are influenced by water deficiency significantly. In the northern rainforest of Xishuangbanna in China, strong radiation and seasonal drought occur frequently. With the increasing of tree height, the xylem pathways increase, resulting in the increasing of water gravity and pathway resistance. In the rainforest, tree is higher and is liable to be influenced by hydraulic limitation. The response of treetop leaves to hydraulic limitation and seasonal drought in higher trees is particularly important to the study of seasonal rainforest. In order to understand the adaptation strategies of rainforest trees, the changes of leaf anatomical structure, pigment content, and water use efficiency (WUE) under varied tree heights of a liana plant Fissisfigma polyanthum (Hook. f. et Thoms.)Merr. and three co-existing arbors of Sapium baccatum Roxb, Litsea pierrei var. szemois liou and Garcinia cowa Roxb were studied in the rainforest of Xishuangbanna, China. Differences in leaf structure, pigment content and WUE were compared among the four tree species. The results showed that the G. cowa and L. pierrei have thicker leaf (310.14, 319.73 μm), thicker cuticle (6.06, 5.13 μm) and bigger cells (21.48,27.09 μm). In addition, their photosynthetic pigments content were lower compared to the other two species. The palisade tissue occupied larger proportion of the leaf transverse section, and the pigments content were higher in the F. polyanthum than three arbor species. However, the F. polyanthum had thinner leaf (147.67 μm) and lowest WUE, and the S. baccatum had the highest WUE. The leaf thickness, palisade tissue and cuticle thickness, LMA, P/S, and TPM/LT of measured four tree species increased with the increasing of crown height, and the F. polyanthum had the largest increasing. Meanwhile, the leaf chlorophyll and carotenoid content of four tree species reduced with the increasing of crown height. The leaf δ13C value and WUE of four tree species increased with the tree height, where the △ value has an opposite trend. The WUE of F. polyanthum had a small change along tree height than the arbor species. The above results showed that the upper crown leaves of four tree species exhibited xeromorphic structure and high WUE. These xeromorphic structure and physiological characters suggests that the trees may suffer from water stress. In order to reduce the influences of relative water shortage, the water loss of treetop leaves was minimized through reducing stomatal conductance, and the WUE was increased resultantly. Simultaneously, the reduced stomatal conductance led to the decreasing of photosynthesis. The fact of low photosynthetic pigment contents in the upper crown leaves indicates the reduced ability of photosynthetic carbon assimilation in treetop leaves. Xeromorphic structure may limit cell division and expansion, then the gas exchange and carbon assimilation capability are restricted resultantly. However, respiration consumption increases with the spread of tree crown. The nutrient shortage limits carbon investment on new leaf growth, and the tree growth is limited ultimately. These findings support the hypothesis of hydraulic limitation that the height growth of big trees slowed down through reduced absorption of irradiance and carbon, which is caused by the hydraulic limitation at treetop arising from increased pathway resistance. 参考文献 相似文献 引证文献

Diversity of Cultivable Actinomycetes in Tropical Rainy Forest of Xishuangbanna, China

In order to obtain much more un-known actinomycetes for discovering new drug lead, one hundred soil samples were collected from five national natural protection areas of tropical rain forests, Mengla, Menglun, Mandian, Xiaomengyang and Guanping, in Xishuangbanna, Yunnan, China. 1652 purified cultures of actinobacteria were isolated from these samples by using 5 media. The 16S rRNA gene sequences of 388 selected strains were analyzed, and the phylogenetic analysis was carried out. 35 genera which belong to 8 orders and 14 families of the Class actinobacteria were identified. It is showed from research results that actinomycete diversity in tropical rain forest of Xishuangbanna is the highest comparing with all areas studied in our laboratories before. Selective isolation methods for un-known actinomycetes from soil samples, including medium and inhibitors are discussed in this paper.

Bird conservation in extremely small tropical rainforest patches in southwest China

Tropical forests support high levels of avian diversity but these areas have been impacted by extensive deforestation. The lowland tropical rainforest of Xishuangbanna in southwest China is one such impacted hotspot. In this region, rubber (Hevea brasiliensis) plantations have replaced most of the original forest, but numerous small fragments of forest remain. To assess the value of these fragments to avian diversity, we classified the fifteen selected remnant forest patches into three size categories, <1ha, 1–3ha, and 3–6ha, and conducted avifauna surveys. We found that 97 bird species inhabit the fragments and that bird diversity increases with patch area. The resident species composition similarity index was low among forest patches, both within and across size categories, and also low between the wet and dry seasons. Ground insectivores, frugivores and large bird species were the most vulnerable to habitat fragmentation. Our study encouragingly shows that fragments can play an important role in bird conservation in regions that now lack large tracts of natural forest; however, current patches are too small to support stable annual populations of some species, while others are more tolerant of fragmentation. We discuss these findings and provide conservation strategies to improve bird conservation within rubber plantations in southern China.

Tree species diversity of a 20-ha plot in a tropical seasonal rainforest in Xishuangbanna, southwest China

We censused all free-standing trees ≥1 cm diameter at breast height (dbh) in a 20-ha plot established in a tropical seasonal rainforest in Xishuangbanna National Nature Reserve, southwest China. A total of 95,834 free-standing trees ≥1 cm dbh were recorded, and 95,498 individuals (accounting for 99.65% of the total), including 468 morphospecies in 213 genera and 70 families, were identified. Thirteen of 468 species (2.78%) had more than 1,000 individual ≥1 cm dbh, which represented 56.36% individuals of the total. On the other hand, 230 of 468 species (49.14%) had a mean density of ≤1 tree per ha, and 69 of 468 species (14.74%) were singletons in the 20-ha plot. The mean species richness, density and basal area per ha were 216.50 species, 4,791.70 stems and 42.34 m2, respectively. Pittosporopsis kerrii (20,918 stems, ≥1 cm dbh) of Icacinaceae and Parashorea chinensis (7,919 stems, ≥1 cm dbh) of Dipterocarpaceae were the two most abundant species dominating the emergent layer and treelet layer, respectively. Compared with other 50-ha plots established in other equatorial regions, tree species richness per ha and tree abundance per ha of the plot were at the moderate level.

Spatial distribution and interspecific associations of tree species in a tropical seasonal rain forest of China.

Studying the spatial pattern and interspecific associations of plant species may provide valuable insights into processes and mechanisms that maintain species coexistence. Point pattern analysis was used to analyze the spatial distribution patterns of twenty dominant tree species, their interspecific spatial associations and changes across life stages in a 20-ha permanent plot of seasonal tropical rainforest in Xishuangbanna, China, to test mechanisms maintaining species coexistence. Torus-translation tests were used to quantify positive or negative associations of the species to topographic habitats. The results showed: (1) fourteen of the twenty tree species were negatively (or positively) associated with one or two of the topographic variables, which evidences that the niche contributes to the spatial pattern of these species. (2) Most saplings of the study species showed a significantly clumped distribution at small scales (0–10 m) which was lost at larger scales (10–30 m). (3) The degree of spatial clumping deceases from saplings, to poles, to adults indicates that density-dependent mortality of the offspring is ubiquitous in species. (4) It is notable that a high number of positive small-scale interactions were found among the twenty species. For saplings, 42.6% of all combinations of species pairs showed positive associations at neighborhood scales up to five meters, but only 38.4% were negative. For poles and adults, positive associations at these distances still made up 45.5% and 29.5%, respectively. In conclusion, there is considerable evidence for the presence of positive interactions among the tree species, which suggests that species herd protection may occur in our plot. In addition, niche assembly and limited dispersal (likely) contribute to the spatial patterns of tree species in the tropical seasonal rain forest in Xishuangbanna, China.

Buttress trees in a 20-hectare tropical dipterocarp rainforest in Xishuangbanna, SW China

Buttresses are prevalent and are important to many ecological processes in tropical rainforests but are overlooked in many rainforest studies. Based on a buttress survey in a 20-hectare plot, this study aims to answer the following questions: (I) Is buttress forming a fixed species characteristic? (ii) Is there any phylogenetic signal for buttress forming across a broad taxonomic scale? (iii) Is buttress forming an inherent feature or simply induced by environmental factors, and how is this relevant to the size of the tree? We surveyed buttresses for all 95940 trees with diameter at breast height (DBH) 10mm in a 20-ha tropical dipterocarp rainforest in Xishuangbanna, SW China. The occurrence of buttresses was compared across different taxa and across different tree-size classes. A phylogenetic analysis was conducted among buttressed and non-buttressed species in order to understand the evolutionary background of buttress formation. This preliminary study showed that buttress trees are very abundant (making up 32% of trees with 100mm DBH) in this 20-ha tropical rainforest situated at the northern edge of the tropics. Fifty-one percent of the 468 tree species in the plot had stems that produced buttresses. Large trees were more likely to develop buttresses than smaller ones. We found that although buttress formation is not a fixed species characteristic, there is a strong phylogenetic signal for buttress formation in larger species.

Abundant and diverse endophytic actinobacteria associated with medicinal plant Maytenus austroyunnanensis in Xishuangbanna tropical rainforest revealed by culture‐dependent and culture‐independent methods

Endophytes are now considered as an important component of biodiversity. However, the diversity of endophytic actinobacteria associated with tropical rainforest native medicinal plants is essentially unknown. In this study, the diversity of endophytic actinobacteria residing in root, stem and leaf tissues of medicinal plant Maytenus austroyunnanensis collected from tropical rainforest in Xishuangbanna, China was investigated with a combination of cultivation and culture-independent analysis on the basis of 16S rRNA gene sequencing. By using different selective isolation media and methods, a total of 312 actinobacteria were obtained, and they were affiliated with the order Actinomycetales (distributed into 21 genera). Based on a protocol for endophytes enrichment, three 16S rRNA gene clone libraries were constructed and 84 distinct operational taxonomic units were identified and they distributed among the orders Actinomycetales and Acidimicrobiales, including eight suborders and at least 38 genera with a number of rare actinobacteria genera. Phylogenetic analysis showed that 32% of the clones in the libraries had lower than 97% similarities with related type strains. Interestingly, six genera from the order Actinomycetales and uncultured clones from Acidimicrobiales have not, to our knowledge, been previously reported as endophytes. Our study confirms abundant endophytic actinobacterial consortium in tropical rainforest native plant and suggests that this special habitat represents an underexplored reservoir of diverse and novel actinobacteria of potential interest for bioactive compounds discovery.

Evaluating the models of stomatal conductance response to humidity in a tropical rain forest of Xishuangbanna, southwest China

The ecosystem-level fluxes of water vapour and carbon dioxide were measured from 2003 to 2006 at a tropical rain forest in Xishuangbanna, southwest China, using the eddy covariance (EC) technique. These flux measurements allowed the canopy-level evaluation of stomatal conductance (g) response to humidity models. The results showed that both the BWB model and the Leuning model discussed here underestimated g at high humidity and overestimated g at the mid-to-low range of humidity. In contrast, the Wang models discussed here (model-ha and model-Da) perfectly described the relationship of g response to humidity. The model comparison results also demonstrated high consistency over all the observation years. The good performance of the Wang model-ha and model-Da indicated that stomatal conductance responds more sensitively to humidity deficit or water vapour pressure deficit than to relative humidity itself at canopy level.

Comparison of carbon content and carbon density of four typical zonal forest ecosystems

Based on the location observation data of the tropical seasonal rain forest in Xishuangbanna, the subtropical evergreen broadleaved forest in Dinghu Mountain, the moist evergreen broad-leaved forest in Ailao Mountain and the broad-leaved Korean pine forest in Changbai Mountain, this paper analyzed and compared the spatial distribution patterns of carbon content and carbon density in four forest ecosystems. The results showed that the carbon contents of vegetation in Ailao Mountain and Changbai Mountain were higher than those in Xishuangbanna and Dinghu Mountain, the carbon contents of different layers in four forest ecosystems were ordered from larger to little as tree, shrub and herbage. The total carbon density was 250.78 t/hm2 in Xishuangbanna, 248.72 t/hm2 in Dinghushan Mountain, 530.13 t/hm2 in Ailao Mountain and 254.67 t/hm2 in Changbai Mountain. The carbon densities of vegetation in Xishuangbanna, Dinghu Mountain and Changbai Mountain were higher than those of soil, but it was opposite in Ailao Mountain.

Evapotranspiration of a tropical rain forest in Xishuangbanna, southwest China

AbstractThe eddy covariance flux measurements from 2003 to 2006 at a tropical rain forest site in Xishuangbanna, southwest China, were used to study the ecosystem evapotranspiration (ET). During the four study years, the mean annual precipitation and air temperature were slightly lower than their long‐term averages (1322 vs 1487 mm and 20·1 vs 21·7 °C, respectively). Mean annual ET in the four study years was estimated at 1029 mm, accounted for 78% of the corresponding annual precipitation. Mean daily ecosystem ET was 2·6 mm day−1 during the dry season from November to April and was 3·1 mm day−1 during the rainy season from May to October. The ET diurnal variations in the cool‐dry season (from November to February), the hot‐dry season (March and April) and the rainy season had similar maximum values, although the soil water content, leaf area index (LAI) and climate conditions differed greatly. ET was mainly controlled by soil water availability in the hot‐dry season, by LAI in the early rainy season (May and June) and by atmospheric conditions in the mid‐to‐late rainy season (from July to October) and the cool‐dry season. The total ET was substantially higher than the corresponding precipitation in the dry season. The extra amount of water evapotranspirated in the dry season was mainly due to the depletion of soil water stored in the previous rainy season. Fog deposition during the dry season also played a role in providing water for ET. Our results indicated the importance of interannual interactions of water balance in the seasonal distribution of ecosystem ET at this site. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Structure and composition of the understory treelets in a non-dipterocarp forest of tropical Asia

Species richness, floristic composition, and structure of understory treelets were investigated in three 1-ha plots, distributed in the undisturbed tropical seasonal rain forest of Xishuangbanna, SW China. We investigated all the woody species except lianas in these plots, compared the differences of species diversity of trees and treelets in these plots and the differences of understory structure between this forest and the typical dipterocarp forests in SE Asia. We found 5089 individuals belonging to 356 species, 189 genera, and 63 families in the three plots. The five most important families were Rubiaceae, Euphorbiaceae, Lauraceae, Meliaceae, and Annonacae. The treelet layer was much more diverse than the tree layer, indicating that result based only on trees may be not an appropriate representation of the diversity status of a particular tropical forest type. The three plots were more similar when the treelet layer was considered than when tree layer was considered. In contrast with the dipterocarp forests in SE Asia, the understory of tropical seasonal rain forest was mainly composed of the trees with small and middle stature at maturity classes. These results indicate that the structure of tropical forest understory may differ not only among continents but also within continent.

First report on mass aggregation of opiliones in China

Gregariousness is a widespread behavior among harvestmen, with reports for species from South and North America, Europe and India. The present note reports an enormous aggregation (300,000 individuals) of the harvestman Pseudogagrella sp. (Sclerosomatidae: Gagrellinae) in the tropical rain forest of Xishuangbanna, southern prefecture of Yunnan Province, China. The aggregation was found during winter months, from November to March, in five adjacent, but clearly defined patches ranging from 1 to 6 m2. Females comprised the greater part of the aggregation and only a few males were found in the patches. With the rise in temperature, the density of individuals reduced considerably, and most of them accumulated in a single patch and finally disappeared by the end of April

New Coelotine spiders from Xishuangbanna Rainforest, Southwestern China (Araneae: Amaurobiidae)

Four new species of coelotine species from Xishuangbanna Rainforest, Yunnan, China are described: Coelotes forficatus sp. nov., Draconarius bannaensis sp. nov., Draconarius exiguus sp. nov. and Draconarius turriformis sp. nov. Morphological descriptions and illustrations of all the four new species are given. The type specimens are deposited in the Institute of Zoology, Chinese Academy of Sciences in Beijing.