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Table of Content
    Volume 16 Issue 1
    27 January 2008

    Hopea chinensis (Dipterocarpaceae) is an endangered tropical species which has been listed in National Key Protected Species of China. It is only found in Shiwandashan of Guangxi now. Research showed that habitat loss caused by human activities and the biological and ecological traits of H. chinensis have led to its endangerment. For details see pages 15–23 of this issue. (Photographed by Shixun Huang)

    Original article
    Effects of island area on plant species distribution and conservation implications in the Thousand Island Lake region
    Que Sun, Jianbo Lu, Jianguo Wu, Fengfeng Zhang
    Biodiv Sci. 2008, 16 (1):  1-7.  doi:10.3724/SP.J.1003.2008.07168
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    Numerous human activities have resulted in landscape fragmentation, and dam construction is one of them that often leads to drastic changes in biodiversity and ecosystem functioning on local and regional scales. In this study, we investigated how island area size affected the distribution of plant species in the Thousand Island Lake region. Also, we compared several conservation scenarios for maximizing plant species diversity. We found 56 tree species and 79 shrub species in 74 islands that were surveyed. These islands and the tree and shrub species they contained were tabulated by island size and analyzed consequently. Our results showed that 11 tree species were affected by island area while 15 were not, and 30 in between being affected and unaffected. For shrubs, 24 species were unaffected, 16 were affected, and 39 species were in between being affected and unaffected to variability in island size. Comparing the cumulative numbers of tree, shrub, and all species in different scenarios of aggregating individual islands by small, medium, large, and mixed categories, respectively, we were able to examine how species richness changed with the increasing total area of habitat and which combination gave rise to the highest species richness. Our analysis revealed that, for a given total area of island habitat, mixing islands of different sizes gave rise to the highest cumulative plant species richness in terms of tree, shrub, or total species richness. The agglomeration of smaller islands resulted in the second highest species richness whereas large islands supported the lowest species richness for the same total area of habitat. Thus, our results suggest that islands of all sizes need to be considered for biodiversity conservation in the Thousand Island Lake region.

    Species and dynamics of floating weed seeds in paddy field
    Ranling Zuo, Sheng Qiang
    Biodiv Sci. 2008, 16 (1):  8-14.  doi:10.3724/SP.J.1003.2008.07094
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    In order to explore effective methods for weed control in paddy fields, we investigated the dynamics of weed seeds in Nanjing from June to November of 2005. A total of 24 weed species representing 15 families were found before seedling transplanting and at late growth stage of rice, while during irrigation stage, 26 species of 17 families were identified from floating weed seeds. The two stages shared 18 weed species, accounting for 56.25% of the total weeds. Most of them belonged to Gramineae, Polygonaceae, Ranunculaceae, Primulaceae, Cyperaceae, Compositae, and Pontederiaceae. There were more weed seeds and more species floating at the edge than in the middle of the paddy field. Some weed seeds could float longer, such as Beckmannia syzigachne, Lysimachia candida, Ranunculus chinensis, Rumex dentatus, Cnidium monnieri, and Alopecurus aequalis. Many floating weed seeds aggregated around rice stubble. In general, seeds began to sink abruptly after floating for two days, and most of them fell to the bottom after eight days. It is obvious that weeds in paddy fields can disperse through floating. Therefore, to filtrate water or clean floating weed seeds can help to reduce the seed weed amount so as to control weeds in paddy fields.

    Biological and ecological characteristics ofHopea chinensis, a plant endemic to Guangxi
    Shixun Huang, Hong Chen, Wenxiu Tang, Wenhua Luo, Yan Wang
    Biodiv Sci. 2008, 16 (1):  15-23.  doi:10.3724/SP.J.1003.2008.07145
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    Hopea chinensis, an important species of seasonal rainforests, is well-known for its timber quality and has a scattered distribution only in Shiwandashan Mountain of Guangxi. To obtain basic information of H. chinensis, we carried out field surveys on the geographic distribution, population structure, and biological characteristics related to phenology. Meanwhile, seeds of H. chinensis were collected for germination and growth experiments. In addition, we briefly discussed the factors causing this species to be endangered and put forward likely conservation strategies. The results indicated that H. chinensis showed a population growth form in general, but being stable in some studied sites. The size distribution of the natural population presented a clumped pattern and shifted to a random pattern with the increase of size classes. The competition in seedlings and saplings ofH. chinensis was more intensive than that in adults. And intraspecific competition contributed higher to the total competition index (CI) than interspecific competition. The seedlings of H. chinensis growed slowly and the fast growth rate occurred in the rainy season. Moreover, the onset for seedlings to begin flower and set fruits was different in different cultivated sites. Seeds ofH. chinensis are not easily to be preserved because of germination in a short time after maturity. We concluded that suitable habitat loss and accordingly decrease of the population size and scale resulted from human activity were the main factors responsible for the endangerment of H. chinensis. Intensively, short seed life span and slow growth could account for low restoration rate of H. chinensis once degraded.

    Spatial distribution pattern of mosquito diversity in residential area along Lancang River in a natural protected territory, “Three Parallel River Region” of Yunnan Province, China
    Junqi Ge, Xiaohong Sun, Zhengda Gong, Guodong Liang, Jinghui Li, Xingming Feng, Liyun Zhang, Bin Li, Shihong Fu
    Biodiv Sci. 2008, 16 (1):  24-33.  doi:10.3724/SP.J.1003.2008.07128
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    The Three Parallel River Region is an epicentre of Chinese biodiversity, which is reputed as one of the world’s 25 major “biodiversity hotspots”. However, few study has been done on the notorious mosquitoes in this area. We surveyed the mosquitoes in relation to latitude and elevation along the Lancang River (24°-30°N, 1,000-3,500 m asl). Adult mosquito samples were captured using UV light traps from July to September 2005 in the mountainous residential areas. A total of 76,458 adult mosquitoes were collected and identified as 36 species of 5 genera in 2 subfamilies. The results showed: (1) species richness gradually decreased with the increasing latitude but showed a single-peak curve pattern along the altitudinal gradient; (2) α diversity decreased first and then increased slightly along the increasing latitude, showing a wave-like curve along the altitudinal gradient; (3) β diversity (Cody index) was higher in the transitional climate zones, and the same pattern was found along the altitudinal gradient, which reflected the influence of geographical environment and climate on the species composition, fauna and diversity distribution pattern of mosquitoes; (4) Mosquito species were classified into three main ecological types by cluster analysis, namely Oriental fauna, Palaearctic fauna, and the transitional fauna between them; and (5) the result from canonical correspondence analysis indicated that precipitation is the key factor influencing spatial distribution pattern of mosquito diversity in the study area.

    Seed predation and dispersal of Ardisia solanacea in habitats with different degree of disturbance
    Jin Zhao, Jin Chen, Shaobin Ma
    Biodiv Sci. 2008, 16 (1):  34-43.  doi:10.3724/SP.J.1003.2008.07231
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    Effective dispersal is one essential course for invasive species on their process of invasion, while study on the effectiveness of seed dispersal was often neglected when predicting species’ invasion. Native to Tropical Asia,Ardisia elliptica is an invasive species in North America. A. solanacea is a tree naturally distributed in southern Yunnan with biological characteristics similar to A. elliptica. In this study, we conducted observation on seed dispersal and seed predation of A. solanacea in two habitats with different degree of disturbance: the Wild Elephant Valley (WEV) with few disturbances and the Xishuangbanna Tropical Botanical Garden (XTBG) with high disturbances. The aim of the study was to understand how disturbances affect seed dispersal and seed predation of A. solanacea.In both habitats, three frugivorous birds were the main seed dispersers, i.e., Alophoixus pallidus, Pycnonotus melanicterus and Iole propinqua. However, the visiting frequency and feeding behaviour differed in the two habitats. In WEV, the visiting frequency of the three birds was 25%, 32% and 26%, respectively; while in XTBG, it was 67%, 8% and 5%, respectively. Only 4% of the birds got first stop far than 10 m away from the fruiting tree after feeding in WEV, but 26% in XTBG. Seed placement experiment indicated that rodents were the major predators to the seeds on ground. The predation rate in both habitats were rather low (2-6%) while seed predation rate in WEV was significantly higher than that in XTBG. In WEV, larvae of Curculionidae were another seed predator, which caused 17.9±3.5% (n = 512) of seeds parasitized. In contrast, no seeds was found to be parasitized by the larvae (n = 489) in XTBG. Disturbance significantly affect the composition and behaviour of animals inhabited. Consequently, those changes may influence seed dispersal and seed predation of related plants, and indirectly, affect the population recruitment of plants.

    Species diversity and distribution of freshwater fishes at Mt. Yinggeling, Hainan Island, China
    Bosco Pui Lok Chan, Xianglin Chen
    Biodiv Sci. 2008, 16 (1):  44-52.  doi:10.3724/SP.J.1003.2008.07021
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    Recent fish surveys at Mt. Yinggeling in the interior of Hainan Island recorded 62 species, including 23 new to the area. Together with literature records, a total of 75 species or subspecies in 59 genera, 20 families and seven orders are now known from the Yinggeling area, representing 70.8% of the known freshwater ichthyofauna and 80.0% of the known endemic fish species of the island. The fish fauna was dominated by rheophilic hillstream species. The northern slope (Nandujiang catchment) and the southern slope (Changhuajiang catchment) shared 42 species in 36 genera (60.0% of total species), but the Nandujiang supports more species characteristic of floodplain while the Changhuajiang is dominated by hillstream species. Various diversity indices revealed that the Nankai River of the Nandujiang catchment and tributaries of the Wanchong section of the Changhuajiang are the best preserved sites with high fish diversity. Fishes concentrated in low- to mid-altitude streams and were rarely encountered above 600 m asl; none was found above 900 m asl. Yinggeling has recently been designated as a nature reserve, and it is crucial to identify sites of high conservation value based on current diversity and distribution patterns, and implement effective conservation measures for the long-term survival of its rich fish fauna.

    Genetic relationships of domestic sheep and goats in the lower reaches of the Yellow River based on microsatellite analysis
    Jianmin Wang, Wenbin Yue
    Biodiv Sci. 2008, 16 (1):  53-62.  doi:10.3724/SP.J.1003.2008.07050
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    We assessed the genetic structure and phylogenic relationships of domestic native sheep and goat breeds from the lower reaches of the Yellow River using 13 microsatellite loci. The results showed that most of these loci were in Hardy-Weinberg disequilibrium (P< 0.01), and about 61.53% of the loci were neutral, indicating that evolutionary forces such as artificial selection and migration might have effect on these breeds. We compared the total and effective number of alleles, gene diversity, polymorphism information content (PIC), Shannon's information index, observed and expected heterozygosities of the breeds. The results showed that genetic diversity was higher in sheep (P< 0.01 orP< 0.05) than in goat. However, the differential effects in different loci were different. Some extent of inbreeding existed in the two genera (He > Ho, FIS > 0). We also analyzed genetic differentiation, genetic distance and population phylogenic topology structure. The results showed that the genetic divergence time of sheep populations was later than that of goat populations from same ancestors. The genetic distance between the two genera was 1.0708-1.5927. The time difference of genetic divergence was between 19,807 and 28,955 years. The degree of genetic differentiation ( FST < 0.05) and genetic distance (0.2185-0.3396) among sheep breeds were lower than those among goat breeds ( FST > 0.15 and 0.3708-0.9868, respectively). The time of genetic divergence was between 3,972 and 5,725 years of the former, and between 6,743 and 17,940 years of the latter. This paper revealed that artificial selection had a profound effect on the shaping of genetic diversity among domestic animals and their genetic differentiation.

    Composition of endophytic fungi in Azadirachta indica from Yuanjiang County of Yunnan
    Shicheng Shao, Shaohua Wu, Youwei Chen, Lidong Wang, Liyuan Yang, Shaolan Li, Zhiying Li
    Biodiv Sci. 2008, 16 (1):  63-67.  doi:10.3724/SP.J.1003.2008.07200
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    In order to explore the endophytic fungi diversity inAzadirachta indica and discover new species and bioactive strains, we studied the composition, quantity, and distribution of endophytic fungi in A. indica from Yuanjiang County of Yunnan, which had been introduced from four different germplasm sources of India (ma, ku, ka and ck). A total of 372 endophytic fungi strains were isolated from the stem and fruits of A. indica. Of these, Colletotrichum (25.54%) was the most prevalent genus, followed by Alternaria (11.56%) and Xylaria(7.80%). The most dominant fungi appeared in the stems from ka (19.89%), ck (19.62%) and ma (18.82%), while the least appeared in the fruits from ka (5.11%) and ku (6.18%). The fungi from ma had the highest richness (29 genera) whereas those from ku had the lowest (23 genera). More species and strains were isolated from the stems than from the fruits. Species composition of endophytic fungi showed no significant difference among different germplasm sources. Some endophytic fungi were host- and tissue-specific. Rich endophytic fungi in A. indica may be an important source of bioactive secondary metabolites, especially the azadirachtins and related tetranortriterpenoids associated with the host plant.

    The economic impact of tourism on local residents in Wolong Nature Reserve
    Yang Liu, Yihe Lü
    Biodiv Sci. 2008, 16 (1):  68-74.  doi:10.3724/SP.J.1003.2008.07089
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    Theoretically, tourism can generate economic benefits for local residents, while whether the benefits can come true in reality is a crucial issue. To obtain the actual direct economic impact that tourism have on local residents, a questionnaire survey was conducted in Wolong Nature Reserve (WNR). Total income generated by tourism, employment opportunities for local participants, and income distributions were included in the questionnaire. The results showed that there’s a considerable gap between actual effects and theoretical expectations from tourism in WNR: the total income generated by tourism was small; the employment opportunities were limited; and the income was unevenly distributed among local participants as well as among local people and outsiders. Measures, including developing new tourism items, establishing educational projects, providing special funds, and implementing a relocation policy, were proposed to improve the effectiveness of tourism as integrated tool for development and conservation.

    Elevational diversity patterns of orchids in Nanling National Nature Reserve, northern Guangdong Province
    Huaizhen Tian, Fuwu Xing
    Biodiv Sci. 2008, 16 (1):  75-82.  doi:10.3724/SP.J.1003.2008.07081
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    Abstract: To determine orchid diversity along an elevation gradient, we conducted a four-year investigation at five management districts (Ruyang, Dadongshan, Chengjia, Longtanjiao and Tianjingshan) in Nanling National Nature Reserve, northern Guangdong Province. The orchid species and individual number, their life forms and habitat conditions were surveyed. Then we analyzed their floristic components and evaluated their endangerment degree according to the IUCN Red List Categories and Criteria (IUCN, 2001). To study the altitudinal distribution of orchids, we divided the study area from 230 m to 1,902 m into nine equal belts at 200-m intervals. We recorded 70 orchid species of 38 genera in total, of which 63 species were recorded in Ruyang. Most of these species had small populations. The orchid diversity presented a hump-shaped pattern along the elevational gradient with a peak at mid-elevations (600-800 m), of which terrestrial, epiphytic, and saprophytic orchids showed the same trend. The endangered species were mainly distributed at 600-1,000 m, where there were better habitats and less human disturbance. The most abundant floristic components were found at 800-1,000 m. The tropical orchids mainly distributed below 1,600 m. There was a higher similarity index between the neighbouring elevational belts. It was concluded that the abundant orchid species at mid-elevation resulted from better thermal and humidity condition, while the conspicuous decline of species richness at low elevation is a result of human disturbance.

    Characteristics ofAlsophila podophylla population and its community in the tropical rainforest in Wuzhi Mountains
    Wenxing Long, Xiaobo Yang, Qingshu Wu, Donghai Li, Tao Guo
    Biodiv Sci. 2008, 16 (1):  83-90.  doi:10.3724/SP.J.1003.2008.07107
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    Alsophila podophyllais a second-class state-protected plant species. After surveying the populations and communities ofA. podophylla in the lowland rainforest and the montane rainforest of Wuzhi Mountains, Hainan Island, we analysed the population characteristics including age structures, spatial patterns and quantities, and the community characteristics including structures and species diversity. The findings showed that A. podophylla population age-structures in the montane rainforest demonstrated a stable type while in the lowland rainforest it was growth-oriented, but the spatial patterns of both were clumped. The average population density of A. podophylla in the lowland rainforest was as 1.7 times as that in the montane rainforest. The soil pH value had negative effects on the average population density, and total P content in soil had positive effects on it. The soil pH value was high and the total P content was low in the montane rainforest, while the case was reverse in the lowland rainforest, hence the discrepancy of pH value and total P content between the montane rainforest and the lowland rainforest accounted for their quantity discrepancy of A. podophylla populations. Besides, according to their path coefficients, the effect that pH value caused to A. podophylla population density was as 2.5 times as that total P content did, thus it meant that soil pH value was the major factor that affected A. podophylla population density. All the community structures were vertically divided into three tree layers, two shrub layers and one herb layer. The Simpson index, Shannon-Wiener index and evenness of the communities were 0.957, 5.305, and 0.811, respectively in the montane rainforest, while in the lowland rainforest they were respectively 0.937, 5.484, and 0.804. In conclusion, A. podophylla population of montane rainforest is different from that of lowland rainforest in characteristics including age-structures, spatial patterns and quantities, and in tropical forest of Wuzhi Mountains A. podophylla community structures are complex and species diversities are rich.

    Culturable bacterial diversity in rhizosphere ofBashania fangiana
    Min Liu, Lubin Li, Kai Yang, Jigang Han, Baocheng Zhu, Zhenhua Peng
    Biodiv Sci. 2008, 16 (1):  91-95.  doi:10.1360/biodiv.070239
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    In order to understand the diversity of culturable bacteria, we collected Bashania fangiana rhizosphere soil in Wolong Nature Reserve in May 2006. Then we isolated and cultured 50 bacteria strains with different morphological character of colonies from the soil. Phylogenetic analysis based on the partial 16S rDNA sequences indicated that the 50 strains were clustered into ten genera: 27 strains of Gammaproteobacteria (42.3%), nine strains of Firmicutes (26.9%), four strains of Actinobacteria (15.4%), six strains of Betaproteobacteria (7.7%), three strains of Alphaproteobacteria (3.9%), one strain closely related to the genus Pedobacter.The dominant bacteria were Pseudomonasand Bacillus. Additionally, we found two potential novel species. The result shows that the bacterial population diversity is abundant in B. fangiana rhizosphere soil.

    Design and implementation of PSDS system, a software for predicting the potential distribution of species
    Hao Deng, Liqiang Ji
    Biodiv Sci. 2008, 16 (1):  96-102.  doi:10.3724/SP.J.1003.2008.07123
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    It is a critical problem in conservation biology to model the geographic distribution of a given species. Potential Species’ Distribution System (PSDS), a new GIS-based system, has been designed and implemented to predict the potential distribution of species by using presence data only. The result, normally overpredicted by traditional Environment Envelope Model, is improved by using hierarchical cluster arithmetic that can reduce the influence caused by outliers. The PSDS system provides functions of data input and output, displaying GIS maps, analyzing the ecological factors of habitat and predicting potential distribution of species, etc. This system is user-friendly and easy to use. As an example, the paper predicts the potential distribution ofSyrmaticus reevesii which is one of the endangered species in china by using presence-only data of four provinces, and gets a good result.

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