Please wait a minute...
Table of Content
    Volume 12 Issue 6
    20 November 2004
    Genetic structure of Xiuning population of Isoetes sinensis, a critically endangered species in China
    CHEN Yuan-Yuan, YE Qi-Gang, LI Zuo-Zhou, HUANG Hong-Wen
    Biodiv Sci. 2004, 12 (6):  564-571.  doi:10.17520/biods.2004071
    Abstract ( 3296 )   PDF (677KB) ( 2409 )   Save
    Related Articles | Metrics
    Allozymic variation and genetic structure of five subpopulations of Isoetes sinensis sampled from Xiuning, Anhui Province were investigated using isoelectric focusing in thin-layer polyacrylamid slab gels. Eighteen loci of 10 enzyme systems were examined and used for the analysis of population genetic parameters. A high genetic diversity was observed in the population, with mean number of alleles per loci (A)=1.7, mean percentage of polymorphic loci(P)=55.56 %, and average expected heterozygosity (He) =0.201. These parameters of genetic diversity were much higher than the average values in fern species. Excess fixed heterozygotes “aabb” found in the population were greatly responsible for deviation from Hardy-Weinberg equilibrium at some polymorphic loci. No significant difference in genetic variation was found among the five subpopulations. Partitioning the genetic diversity indicated that 94.27% of the genetic variation was within subpopulations and only 5.73% existed between subpopulations, which was explained by a genetic bottleneck or founder effect, as well as by the clonal reproduction of this species and “fixed heterozygosity”. Mean gene flow among subpopulations (Nm) was 4.5062 and genetic identities among subpopulations ranged from 0.960 to 0.999, which is suggestive evidence that the Xiuning population is panmictic in its current habitat. Furthermore, the sampled population with a total of 75 individuals consists of only 13 multi-locus genotypes, suggesting a high genetic uniformity within and among subpopulations. Finally, we discuss the risk of extinction of this species in the wild driven by population genetic factors, and conservation strategies.
    Ecophysiological characteristics of seed germination of the relict plant Metasequoia glyptostroboides
    XIN Xia, JING XinMing, SUN HongMei, LIN Jian, WANG XiaoFeng
    Biodiv Sci. 2004, 12 (6):  572-577.  doi:10.17520/biods.2004072
    Abstract ( 3406 )   PDF (590KB) ( 2406 )   Save
    Related Articles | Metrics
    Metasequoia glyptostroboides, known as a “living fossil”that was once widely distributed in the Northern Hemisphere, is now only found in a few restricted places in China. Many researches have been done on this species, but few on its seeds. Seed, as a key phase of spermatophyte life cycle, is important for regeneration and dispersal. Seed germination, which can be considered the initiation of the spermatophyte life cycle, is easily affected by environment.We studied the effects of temperature and light on ecophysiological characteristics of seed germination of M. glyptostroboides. Seed samples were collected from Lichuan City, Hubei Province, and stored at -20℃ before the experiment. A temperature gradient from 10℃ to 35℃ was used to study the effect of temperature on seed germination. Germination percentage, vigor index, and activities of dehydrogenase and antioxidant enzymes were used as a measure of seed vigor and stress resistance. The results indicated that temperature had a strong effect on seed vigor and activities of antioxidant enzymes. The germination rate, vigor index,and activities of dehydrogenase and antioxidant enzymes of M. glyptostroboides seeds were higher when temperature ranged from 19℃ to 28℃, whereas seed vigor declined greatly when the temperature was above 32℃ or below 19℃, and little germination was observed below 10℃. Our results imply that a temperature ranging from 19℃ to 28℃ is suitable for seed germination, with an optimum of 24℃. Seed germination was greatly inhibited by light (65μmol·m-2·s-1, 12 h/d), which implied that the germination of M. glyptostroboides seeds requires dark conditions. The seeds were of poor quality with the percentage of empty seed over 90%. The unsuitable temperature in the original habitat of M. glyptostroboides, together with the poor seed quality might be important factors limiting the regeneration of the species, and this might explain the lack of seedlings and saplings in M. glyptostroboides populations.
    Establishment of a core collection of Changjiang spring sowing soybean
    WANG Li-Xia, LI Ying-Hui, LI Wei, ZHU Li, GUAN Yuan, NING Xue-Cheng, GUAN Rong-Xia, LIU Zhang-Xiong, CHANG Ru-Zhen, QIU Li-Juan
    Biodiv Sci. 2004, 12 (6):  578-585.  doi:10.17520/biods.2004073
    Abstract ( 3149 )   PDF (557KB) ( 2417 )   Save
    Related Articles | Metrics
    Sampling strategy is very important for core collection establishment. In this study, different methods to construct a core collection of Changjiang spring sowing soybean were performed based on data of SSR(simple sequence repeat) markers and agronomic traits in order to optimize the sampling strategy for core collection. The results showed that, based on cluster analysis of SSR data, each of the three methods, i.e., random sampling within each group, sampling by genetic similarity coefficient within each group and sampling by genetic similarity coefficient, could be used to construct a soybean core collection. When SSR allelic reserving ratios were maintained at 90% and 80%, the core collections had higher genetic diversity indices of SSR alleles than if maintained at 70%. Core collections could also be constructed by agronomic and other basic data if there was no molecular data; however, SSR allelic reserving ratio might be decreased, which suggested that assessment of genetic diversity by SSR data was not always consistent with assessment by agronomic data. We found that core collections were heterogeneous, either when created with different sampling methods or with the same sampling method in different repeats, because randomicity always existed in selecting individuals. This indicated that the germplasm to form a core collection was variable, so optimal sampling strategies should be chosen to establish core collections based on different data according to practical or scientific objectives. Integrating phenotypic and genotypic data together would be better for improving the representativeness of core collections.
    Genetic diversity in seven Chinese indigenous sheep breeds based on microsatellite analysis
    YANG Yan, MA Yue-Hui, LU Shen-Jin, ZHANG Ying-Han
    Biodiv Sci. 2004, 12 (6):  586-593.  doi:10.17520/biods.2004074
    Abstract ( 3608 )   PDF (581KB) ( 2614 )   Save
    Related Articles | Metrics
    Genetic diversity in seven Chinese indigenous sheep breeds was estimated using 26 microsatellite markers. The allele frequency, mean heterozygosity, polymorphism information content, effective number of alleles, genetic distance,and dendrogram analysis were used to assess the genetic variability and genetic relationships among the seven breeds. A total of 278 alleles were detected, and the 26 loci were highly polymorphic. The effective number of alleles ranged from 2.1288 to 13.3924, mean heterozygosity of loci from 0.0629 to 0.5903, mean heterozygosity of breeds from 0.3633 to 0.4489, and polymorphism information content from 0.6628 to 0.8712. In the Neighbor-Joining tree based on Nei′s standard genetic distance, the seven sheep breeds formed two groups: Hazake sheep, Altay Fat-rumped sheep and Bayinbuluke sheep were closely related, then clustered with Baizang sheep and Heizang sheep; and the second group consisted of Hu sheep and Jinzhong sheep. The dendrogram relationship between different sheep breeds was generally in accordance with their origins, breeding history and localities.
    An ecological study on the benthos of the rocky intertidal zone in Quanzhou Bay.Ⅰ.Species diversity and its distribution
    ZHENG Cheng-Xing, LI Rong-Guan, JIANG Jin-Xiang, ZHENG Feng-Wu, WANG Jian-Jun, HUANG Xin-Guang, LIN Jun-Hui
    Biodiv Sci. 2004, 12 (6):  594-610.  doi:10.17520/biods.2004075
    Abstract ( 3124 )   PDF (766KB) ( 2348 )   Save
    Related Articles | Metrics
    A survey on four rocky intertidal transects in Quanzhou Bay was carried out from November 2001 to August 2002. A total of 6687 specimens in 216 sampling frames were collected, which yielded 324 species. These include 17 algae, 102 annelids, 96 molluscs, 62 arthropods, 11 echinoderms and 36 other animals. The results suggest that, affected by currents and waves, the number of species in horizontal distribution declines in order from Fushan (206), Xiayang (197), Dazhuidao Island (193) to Antou (166). The vertical distribution of species is affected mainly by tides and waves. A common characteristic of the transects in different intertidal areas is that the middle intertidal area has the greatest number of species (129-156 species), while the high tidal zone has the smallest number of species (9-20 species). The low tidal zone is intermediate, with 87 to 116 species. The number of species varies with change of seasons, demonstrating the adaptability of marine organisms to the temperature of water. The number of species range in a declining order from summer(190), spring(164), autumn(158) to winter(150).
    Species composition and diversity of fig wasps and figs in Yunnan
    YANG Da-Rong, XU Lei, PENG Yan-Qiong, WEI Zuo-Dong, DUAN Zhu-Biao
    Biodiv Sci. 2004, 12 (6):  611-617.  doi:10.17520/biods.2004076
    Abstract ( 3499 )   PDF (591KB) ( 2546 )   Save
    Related Articles | Metrics
    Hymenoptera of the family Agaonidae (fig wasps) are the obligate pollinating insects of fig trees (Ficus spp.), and fig syconium is the only host of fig wasp. For the pollination of their flowers, fig trees are dependent upon fig wasps. For their reproduction and growth, fig wasps are dependent upon the gall (ovaries) of the figs, in which their larvae develop. Thus, the two groups share a symbiotic relationship. Species diversity and richness of fig and fig wasp are highest in Yunnan among all the provinces of China. Our study shows that the fig wasps collected from Yunnan include 50 species of 12 genera, which are mainly distributed in the tropics and south sub-tropics below an altitude of 1600 m. Both figs and fig wasps decrease in species number with increasing altitude. Above an altitude of 3700 m, no natural fig tress were found, except for cultivated species. Species diversity increased in the following order: northwestern Yunnan (H′= 0.6902), northeastern Yunnan (H′= 0.6976), central Yunnan (H′= 0.9211), southeastern Yunnan (H′=1.2164), western Yunnan (H′=1.5017), and southern Yunnan (H′=1.6441).
    Evaluation of amphibian species diversity in Fujian
    GENG Bao-Rong
    Biodiv Sci. 2004, 12 (6):  618-625.  doi:10.17520/biods.2004077
    Abstract ( 3676 )   PDF (594KB) ( 2159 )   Save
    Related Articles | Metrics
    Evaluation of regional species diversity is an important component in studying global biodiversity. In this paper, amphibian species diversity (ASD) in Fujian Province was evaluated using the G-F index and cluster analysis with chord distance (CRD) to measure between-groups linkages. The analysis was conducted on the amphibian compositions in 22 county or city areas and five zoogeographic divisions. Differences between counties or cities were significant. For the G-index of ASD, Wuyishan scored the highest value (2.465) among the counties or cities; and central Fujian zoogeographic division scored 2.534, the highest value of the five divisions. The G-index, F-index and G-F index of the entire Fujian ASD are 2.978, 4.863 and 0.388, respectively. The cluster analysis based on CRD showed that the northern, eastern, and western Fujian zoogeographic divisions, located in Central China Zoogeographic Region, formed a group, which successively clustered with the central and the southern zoogeographic divisions in the South China Zoogeographic Region. The linkage pattern based on counties or cities is similar to that based on zoogeographic divisions. The author suggests that Datian County, though located in central Fujian, should be placed in the western Fujian zoogeographic division.
    Special Issue
    The distribution and introduction pathway of alien invasive species in China
    XU Hai-Gen, QIANG Sheng, HAN Zheng-Min, GUO Jian-Ying, HUANG Zong-Guo, SUN Hong-Ying, 6, HE Shun-Ping, 7, DING Hui, WU Hai-Rong, WAN Fang-Hao
    Biodiv Sci. 2004, 12 (6):  626-638.  doi:10.17520/biods.2004078
    Abstract ( 4583 )   PDF (777KB) ( 4233 )   Save
    Related Articles | Metrics
    Alien invasive species have become a serious environmental issue throughout the world. It is necessary to launch a nationwide investigation on alien invasive species, so as to obtain baseline data, identify causes of invasion, and put forward effective control strategies and measures. Data on classification, origin, pathway and environmental impacts of alien invasive micro-organisms, invertebrates, amphibians and reptiles, fish, birds, mammals, weeds, trees in terrestrial and aquatic ecosystems and alien invasive species in marine ecosystems of China were analyzed, based on literature research, field survey and consultation. 283 alien invasive species have been identified in China, and the number of species of alien invasive micro-organisms, aquatic plants, terrestrial plants, aquatic invertebrates, terrestrial invertebrates, amphibians and reptiles, fish, and mammals were 19, 18, 170, 25, 33, 3, 10, and 5, respectively. The proportion of alien invasive species originating from America, Europe, Asia, Africa and Oceania were 55.1%, 21.7%, 9.9%, 8.1% and 0.6%, respectively. Many institutions and individuals in China lack adequate knowledge of ecological and environmental consequences caused by alien invasive species, with some blindness in the introduction of alien species. For instance, 50.0% of alien invasive plants were intentionally introduced as pasture, feed stock, ornamental plants, textile plants, medicinal plants, vegetables, or lawn plants. 25% of alien invasive animals were intentionally introduced for cultivation, recreation, or biological control. In addition, much effort has been made on introduction of alien species, and little attention has been paid to the management of introduced alien species, which may allow their escape into natural environments and potential threats to the environment. There are also gaps in the quarantine system in China. All invasive micro-organisms were unintentionally introduced, through timber, seedlings, flowerpots, or soil. 76.3% of alien invasive animals invaded through commodity or transportation facilities because of the failure of quarantine. It is recommended that quarantine measures should be strictly implemented. At the same time, the intentional introduction of alien species should be strictly managed and a system of risk assessment should be implemented.
    Local people′s responses to policies in Wolong Nature Reserve, Sichuan
    XU Jian-Ying, CHEN Li-Ding, LU Yi-He, FU Bo-Jie, YANG Shuang
    Biodiv Sci. 2004, 12 (6):  639-645.  doi:10.17520/biods.2004079
    Abstract ( 2778 )   PDF (609KB) ( 2026 )   Save
    Related Articles | Metrics
    To sustain long-term coexistence, it is important to avoid conflicts between protected area management and local people′s needs. Management policies implemented in protected areas play an important role in shaping their relationships with local people. To assess local people′s responses towards policies is a crucial step in information collection for decision-making. Based on a questionnaire survey and cross-tabulation analysis, we conducted a comprehensive investigation of local people′s responses to current policies, developmental conditions and policy scenarios in Wolong Nature Reserve, aiming to determine the factors affecting conflict mitigation between the reserve management and local people. Our results showed two potential conflicts existed threatening the biodiversity conservation and reserve management by the comprehensive analysis of current policies such as the “Grain for Green” Project, the Natural Forest Protection Project and the Substitute Electricity for Fuelwood Program. One conflict was that between the decrease of cropland holdings and overstocking of the labor force. The other was between the increase of electricity prices and the decrease of subsidies from the Natural Forest Protection Project. Local people′s responses were closely related to their personal characteristics such as gender and educational level, while responses to policy scenarios of relocation were associated with their residential place and educational level. We propose some measures to mitigate potential conflicts and modify management policies, including strengthening public participation, improving educational levels of and providing employment chances for local people, establishing reasonable prices for electricity and implementing a relocation policy.

  • wechat:swdyx_wx