Impact of The Three Gorges Project on Biodiversity
    null

    Default Latest Most Read
    Please wait a minute...
    For Selected: Toggle Thumbnails
      
    Effects of point source pollution from a phosphorus chemical factory on terrestrial plant communities in the Three Gorges Reservoir area
    Chuanlong Li, Zongqiang Xie, Changming Zhao, Gaoming Xiong, Li Zou
    Biodiv Sci    2007, 15 (5): 523-532.   DOI: 10.1360/biodiv.070083
    Abstract4294)      PDF (375KB)(3101)       Save
    In order to reveal the response of terrestrial plant communities to pollution in the Three Gorges Reservoir area, we selected 32 sampling sites with similar environmental factors but different distances from the pollution source, a phosphorus chemical factory. A total of 284 vascular plant species were recorded in these sites, belonging to 182 genera and 76 families, including 35 tree species, 139 shrub species and 110 herbage species. Species richness and Pielou evenness index were used to measure species diversity. Species richness in polluted area was 32–67, while in control area it was 47–82. Pielou evenness index of tree layer was 0.1161–0.8509, while those of shrub layer and herb layer were 0.1763–0.3249 and 0.0443–0.2601, respectively. The results showed that both species richness and Pielou evenness index were influenced by the point source pollution. Species importance values showed significant differences between polluted area and control area. Dominance of different species had changed, and some species even disappeared under the pressure of pollution, indicating a process of species replacement in plant communities. Such species replacement can provide a scientific basis for species selection for restoration of human-damaged ecosystem. The natural regeneration of Quercus variabilis was insensitive to pollution, while Cupressus funebris was effected seriously. Therefore, the results implied that point source pollution in the Three Gorges area had a strong negative effect on the composition and diversity of terrestrial plant communities. Further study needs to be carried out to study the long-term succession of the plant communities.
    Related Articles | Metrics
    Cited: CSCD(3)
      
    Spatial pattern of plant species diversity in the inundation and resettle- ment region of the Three Gorges Reservoir
    Changming Zhao, Weilie Chen, Handong Huang, Ziqiang Tian, Yue Chen, Zongqiang Xie
    Biodiv Sci    2007, 15 (5): 510-522.   DOI: 10.1360/biodiv.070084
    Abstract4601)      PDF (689KB)(3877)       Save
    To reveal the spatial pattern of plant species diversity in the inundation and resettlement region of the Three Gorges Reservoir, 129 plots were investigated along 14 sample belts. The sample belts were located at different aspects on both sides of Yangtze River, within the counties of Xietan, Wushan, Fengjie, Wanzhou, Fuling and Chongqing as well as the dam area. The investigated plots in each sample belt were taken at altitude intervals of approximately 50 m within an altitude range of 70–610 m above sea level. The spatial pattern along the altitude gradient was firstly examined by adopting the number of species and the Shannon-Wiener index based on coverage as species diversity indices. Secondly, DCCA (Detrended Canoni-cal Correspondence Analysis) was used to illustrate the relationship among environmental variables and spe-cies diversity indices to explore factors involved with spatial patterns of species diversity. The results indi-cated that the species diversity was higher on the southern side of Yangtze River than on the northern side. Species diversity increased but not so evidently with an increase of altitude. There was no evident correlation found between stream position (upstream or downstream) and species diversity, however it was found that the belts with the highest species diversity were located in the dam area and Wanzhou, while the lowest were in Chongqing and Wushan. DCCA revealed that the environmental variables most affecting species diversity was firstly the southern or northern location on the Yangtze River and secondly altitude. DCCA also revealed that the coverage of the canopy layer positively affected the species diversity, but the coverage of shrub layer affected it negatively. This suggests that the species diversity was determined by the characteristics of com-munity structure, especially the coverage of the arbor layer. It was concluded that the relationships between the spatial pattern of species diversity and environmental factors were altered by human disturbances, which are long-term and heterogeneous in space and intensity. The species diversity of the disturbed community was determined by characteristics of community structure, especially the coverage of the canopy layer.
    Related Articles | Metrics
    Cited: CSCD(15)
      
    Spatial and temporal pattern of seed rain of Abies fargesii in Shennongjia Nature Reserve, Hubei
    Li Zou, Zongqiang Xie, Qingmei Li, Changming Zhao, Chuanlong Li
    Biodiv Sci    2007, 15 (5): 500-509.   DOI: 10.1360/biodiv.060234
    Abstract4575)      PDF (345KB)(3827)       Save
    Abies fargesii is endemic to China and its distribution center is located in Qinling-Bashan Mountains. To study the spatial and temporal pattern of seed rain of Abies fargesii, we conducted experiments from 9 October to 24 November in Shennongjia Nature Reserve, Hubei in 2005. The results showed that patterns of Abies fargesii seed rain were different in three communities. In Abies fargesii–Fargesia nitida community, the average seed rain intensity was 167.93±111.14 seeds per m2, in which the proportion of viable seed was 22.31%; and the seed rain pattern mainly showed clump distribution which peaked in 27 October to 2 No-vember. In Abies fargesii–Skimmia reevesiana community the seed rain intensity was just 16.41±14.41 seeds per m2 in which viable seed only accounted for 3.05%. In Abies fargesii–Sorbus koehneana community, seed traps were set up in four lines at 90°intervals, of which two lines run directly up and down the hill slope. In this community, the seed rain intensity peaked from 15 October to 21 October. And the most quantity of seed rain was concentrated under the crown, which accounted for 87.95% of the total amount. One-Way ANOVA analysis showed that no significant differences existed among four directions but significant difference existed between 0–6 m and other distance from the center mother tree in terms of seed rain quantity. The distri-bution pattern of seed rain in Abies fargesii–Sorbus koehneana community fitted the equation y=ae–bx2. The result showed although Abies fargesii had high seed rain intensity, but inviable seeds accounted for a large proportion, and the dispersal distance of seed rain was limited. These characteristics would influence the pat-tern and regeneration of Abies fargesii population.
    Related Articles | Metrics
    Cited: CSCD(19)
      
    Ecophysiological responses of Buxus ichangensis to summer waterlogging
    Yanhong Xue, Fangqing Chen, Dayong Fan, Zongqiang Xie
    Biodiv Sci    2007, 15 (5): 542-547.   DOI: 10.1360/biodiv.060236
    Abstract3582)      PDF (393KB)(3848)       Save
    As a widely distributed shrub species on the hydro-fluctuation belt in the Three Gorges Area, Buxus ichangensis is of vital importance for conservation of soil and water, and recovery of vegetation in this area. To determine its tolerance to flooding, we performed simulated waterlogging on this plant and then examined its responses in photosynthesis, roots activity and pigment contents. Our experiment showed, all the B. ichangensis plants could survive after 60-day inundation treatment, partly because of morphological adapta-tion triggered by the waterlogging, such as development of lenticels and adventitious roots. However, the variables of net photosynthesis rate, stomatal conductance and root activity reduced to 19.24%, 24.04% and 4.78% of the control, respectively, and the decreasing amplitude varied in different flood periods, sig-nificantly decreasing primarily and resumed a little at the end of experiment. Chlorophyll A content signifi-cantly decreased along with waterlogging time, whereas chlorophyll B and carotenoid contents presented indistinctive changes after different waterlogged durations. Based on these, we concluded that B. ichangensis had strong tolerance to summer flooding. We provided some suggestions on how to utilize the species in the restoration of degraded riparian vegetation in reservoir area of hydroelectric project.
    Related Articles | Metrics
    Cited: CSCD(10)
      
    Vegetation and plant species richness on six pre-islands, the Three Gorges Reservoir
    Gaoming Xiong, Zongqiang Xie, Jiangshan Lai, Guozhen Shen, Changming Zhao
    Biodiv Sci    2007, 15 (5): 533-541.   DOI: 10.1360/biodiv.070085
    Abstract3725)      PDF (310KB)(2908)       Save
    We studied the vegetation on six pre-islands (land areas which will become islands as a result of flooding) in the Three Gorges Reservoir with a focus on plant species richness for each community. A total of 28 community types were found on these pre-islands, comprising of 12 hassocks, 7 shrubs, and 9 forests. The results showed that natural vegetation was characterized by intense degradation, implied low vegetation cov-erage, restricted distribution of forests, low community diversity and high ratio of ruderal community types. The species richness of wild vascular plants on the six pre-islands was 126, 157, 175, 189, 242, and 254, re-spectively. The average species richness was 42.9 for forest, 15.96 for shrub, and 17.89 for hassock commu-nities. In all hassock communities, species richness was high in ruderals but was low in typical degraded hassocks. Species richness was generally low in all shrub communities. In the process of secondary succes-sion from conifer-broadleaf forest to broadleaf forest, species richness fluctuated remarkably. Exotic plants significantly impacted the landscape, resulting in degradation of the natural vegetation. These pre-islands are valuable for scientific research, we suggest establishing some nature reserves on them.
    Related Articles | Metrics
    Cited: CSCD(8)
      
    Seed dormancy and germination characteristics of Manglietia patungen-sis, an endangered plant endemic to China
    Faju Chen, Hongwei Liang, Xu Wang, Zhengquan He, Fenglan Li
    Biodiv Sci    2007, 15 (5): 492-499.   DOI: 10.1360/biodiv.060238
    Abstract3909)      PDF (627KB)(3532)       Save
    Manglietia patungensis, an endangered tree species endemic to China, is listed in National Key Protected Species. To explore the underlying mechanisms relevant to the impediment in its sexual reproduction, we studied the morphological and physiological characteristics of seeds during its dormancy and after-ripening process. The results showed that the incomplete development of embryos was the main reason for seed dormancy. The immature embryos continued differentiating and developing during the after-ripening process. As the seed coat was permeable, it would not induce seed dormancy. Germination inhibitors existed in different parts of seeds, especially in the endosperm, which was believed to be a major factor for the ger-mination delay. Endogenous hormone ABA and IAA played an important role in the dormancy and germina-tion of seeds. ABA was the key factor for seeds dormancy while IAA benefited germination. Therefore, the change of IAA/ABA ratio was crucial to seed dormancy and germination. Only at a temperature as low as 4°C and in a humid environment, could M. patungensis seeds complete the morphological and physiological after-ripening process. In fact, it was observed that the after-ripening process of M. patungensis seeds oc-curred in autumn, a season characterized by low rainfall and drought in this area. Evidently, viability loss of seeds caused by water deficit during the after-ripening period may explain the poor regeneration of this spe-cies.
    Related Articles | Metrics
    Cited: CSCD(32)
      
    Allelopathic effects of Eupatorium adenophorum on five species of the family Gesneriaceae
    Yuanbo Li, Han Xu, Lei Shi, Zhenyu Li
    Biodiv Sci    2007, 15 (5): 486-491.   DOI: 10.1360/biodiv.060213
    Abstract4345)      PDF (244KB)(3744)       Save
    Eupatorium adenophorum (Compositae), a highly invasive plant in southwestern China, has increasingly invaded the habitats of the gesneriaceous plants. All species of Gesneriaceae in China have been listed in China’s Red List and some of them have been categorized as the National Key Protected Species. To examine the possible allelopathic effect of E. adenophorum on Gesneriaceae, five species in three genera of Gesneriaceae (Chirita spinulosa, C. heterotricha,C. liboensis, Aeschynanthus acuminatus, and Titanotrichum oldhamii) were treated with three parts of E. adenophorum, i.e., aqueous root, stem, and leaf extracts (8%), respectively. The results indicated that aqueous leaf extracts of E. adenophorum had very different impacts on C. spinulosa, C. liboensis and C. heterotricha, of which it was the most obvious on C. spinulosa. Seedling growth of C. spinulosa were totally inhibited when aqueous leaf extracts 2.4%, 3.2% and 4.0%. The aqueous stem extracts of E. adenophorum showed some impacts on T. oldhamii. Seedling growth of T. oldhamii were inhibited 40% when the stem extracts of E. adenophorum was 1.6% . Aqueous leaf and stem extracts of E. adenophorum had little effect on seedling growth of A. acuminatus. However, aqueous root extracts of E.adenophorum also had no significant suppression on these five species. Therefore, our experiments con-firmed allelopathy of E. adenophorum on Chirita and Titanotrichum but not so much on Aeschynanthus. The gesneriaceous species on rocks seemed more susceptible to allelopathy of E. adenophorum than their allied species on trees.
    Related Articles | Metrics
    Cited: CSCD(18)
      
    Growth trends of Crofton weed (Eupatorium adenophorum) seedlings in different habitats
    Aifang Li, Xianming Gao, Weiguang Dang, Jinfang Wang
    Biodiv Sci    2007, 15 (5): 479-485.   DOI: 10.1360/biodiv.060231
    Abstract3946)      PDF (356KB)(3192)       Save
    Crofton weed () seeds took a speculative strategy to germinate, and its seeds would germinate at any time all the year round as long as the conditions were suitable. The peak of the seeds’ germination occurred in the rainy season while few seeds germinated during the dry seasons. The un-flowering individuals of Crofton weed keep growing all year, and its growth rate would be influenced by the illumination intensity, humidity and temperature distinctly. The results showed that all of the growth pa-rameters of seedlings germinating during autumn changed slowly in the dry season. The optimum habitat was the sunny sites, then entirely shaded ones, and the shrub habitats were the last. The fastest growth of the seedlings period began in June and ended in October. Usually the seedling would flower and seed during the first dry season, but those germinated later or did not develop well would keep vegetative growth without flowering. The growth dynamic of un-flowering seedlings was similar to those flowering and seeding, but the life history periods between them were different: only those crossing two or enven more winters could the former seedlings bloom and fructify to finish their life history circle. The result of this study further indicated that reinforcement each other of both sexual reproduction and clone would promote the renewal and spread of their population increase of Crofton weed.
    Related Articles | Metrics
    Cited: CSCD(14)