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1.
重庆中梁山海石公园石灰岩山地植物多样性研究   总被引：1，自引：0，他引：1  
以25个5 m×5 m的样方为基础,研究了海石公园20 a无干扰的石灰岩山地灌丛植被情况.运用重要值、丰富度指数、均匀度指数和多样性指数分析了该区植物组成与多样性,并与云阳人工柏木林和缙云山草珊瑚群落对比.结果表明:在625 m~2样地中有维管束植物78种,群落各层次的丰富度大小格局依次为灌木层,草本层,藤本植物;多样性大小格局依次为灌木层,草本层或等于藤本植物;均匀度大小格局依次为藤本植物,灌木层,草本层.相对于云阳人工柏木林和缙云山草珊瑚群落,本群落的多样性指数较高.
Abstract：
The species composition and diversity of plants on the Haishi Park limestone shrubland without anthropogenic disturbance for 20 years were studied based on data from 25 5 m×5 m plots. Important value index, richness index, species diversity index and evenness index were used to analyze the species composition and diversity of plants in the region and a comparison was made between the results of the study with the Cupressus funebris forest in Yunyang and the Sarcandra glabra communities in the Jinyun Mountains. A total of 78 species of vascular plants were found in the 625 m~2 plots. Richness index was in the order of shrub layer ＞ herb layer ＞ liana layer; species diversity index in the order of shrub layer ＞herb layer ≥ liana layer and evenness index in the order of liana layer ＞ shrub layer ＞ herb layer. Species diversity index in Haishi. Park was higher than that in C. funebris forest in Yunyang and S. glabra communities in the Jinyun Mountains.  相似文献   

2.
Bemisia tabaci is a cryptic species complex, causing significant loss on many agriculturally important crops worldwide. Knowledge on species composition and diversity within B. tabaci complex is critical for evolving sustainable pest management strategies. Here we investigate the whitefly species complex in soybean in major soybean growing states of India. The mitochondrial cytochrome oxidase gene subunit-1(mt COI) based phylogenetic relationships established using Bayesian methods indicated the existence of three cryptic species namely AsiaⅠ, AsiaⅡ1, and AsiaⅡ7. All the haplotypes detected in the study could be assigned to these three cryptic species following the species demarcation criteria of 3.5% divergence threshold. Of these, AsiaⅡ1 was found to be predominant with wide spread distribution across the surveyed regions from cool temperate zones to hot and humid tropical plains. On the contrary, cryptic species AsiaⅡ7 showed localized distribution. The AsiaⅡ1 exhibited the highest haplotype diversity and AsiaⅠ showed high level of nucleotide diversity. There was a significantly high genetic differentiation among these three cryptic species. The MEAM 1, a dreadful invasive species was not detected in the specimens tested in the current study. The diversity and distribution of three cryptic species is discussed in the light of current knowledge on distribution of whitefly species in India and yellow mosaic disease observed during sampling survey.  相似文献   

3.
Based on data from systematic investigation of 3 outdoor st ored bulk grain masses in Jingmen City, Hubei Province (112°07′E, 30°02′N) i n 1992, insects of 37 species were identified with two classes, seven or ders, twent y-six families. Twenty-six beetles are main species accounting for 64.7% of t h e community. Superiority index estimation indicated that the Crptolestes ferru gineu s(Stephens), Cryptolestes minutus（Oliver) and Rhizopertha dominica Fa b. were the most destructive pest in outdoor stored bulk grain mass. In spring, the spe c ies diversity, abundance, evenness and the population size in the community incr ease. In July, however, the species diversity and evenness maximize. The insect communitvy is low in stability and diversity in the surface layer. In the bottom layer, however, species diversity and stability is higher.  相似文献   

4.
Nutrient addition can affect the structure and diversity of grassland plant communities, thus alter the grassland productivity. Studies on grassland plant community composition, structure and diversity in response to nutrient addition have an important theoretical and practical significance for the scientific management of grassland, protection of plant diversity and the recovery of degraded grassland. A randomized block design experiment was conducted with six blocks of eight treatments each: control(no nutrient addition) and K, P, N, PK, NK, NP, and NPK addition. We evaluated plant composition, height, coverage, density, and aboveground biomass to estimate primary productivity and plant diversity. Results showed that all treatments increased primary productivity significantly(P0.05) with the exception of the K and the NPK treatments had the greatest effect, increasing aboveground biomass 2.46 times compared with the control(P0.05). One-way ANOVA and factorial analysis were used for the species richness, Shannon-Wiener index, Pielou index and aboveground biomass, and the relationships between the diversity indices and aboveground biomass were determined through linear regression. We found that fertilization altered the community structure; N(but not P or K) addition increased the proportion of perennial rhizome grasses and significantly reduced that of perennial forbs(P0.05), thus it presented a trend of decrease in species richness, Shannon-Wiener and Pielou indexex, respectively. Only the main effects of N had significant impacts on both the diversity indices and the aboveground biomass(P0.05), and the interactions between N-P, N-K, P-K and N-P-K could be neglected. With fertilization, plant diversity(correlation coefficient, –0.61), species richness(–0.49), and species evenness(–0.51) were all negatively linearly correlated with primary productivity. The correlations were all significant(P0.01). Scientific nutrient management is an effective way to improve grassland productivity, protect the plant diversity as well as recover the degraded grassland.  相似文献   

5.
The red imported fire ant, Solenopsis invicta, is a problematic invasive species in China since at least 2003. Over the past 15 years, a numerous studies were published on the impacts of this species on flora, fauna, and ecosystem function in natural and agricultural systems. We reviewed the literature on S. invicta invasion biology and impacts on biodiversity in South China. Both monogyne and polygyne colonies of S. invicta were introduced to China and polygyne colony is the dominant type. The range expansion rate of S. invicta may reach 26.5–48.1 km yr–1 in China. S. invicta forage activities occur year-round, peaking in the summer and fall in South China and show a preference for insects and plant seeds. We describe the ecological impacts of S. invicta on various habitats in South China, including arthropod community structure disruption and decreases in diversity and abundance of native ant species. S. invicta can replace the role of native ants in mutualisms between ants and honeydew-producing Hemiptera, which results in loss of important food resources for native ants and natural enemies of hemipterans. Further research is required to assess the complex ecosystem-level impacts of S. invicta in introduced areas.  相似文献   

6.
Avocado is one of the most important crops in the world, and Mexico is the largest producer of this fruit. Several insect pests affect its production, and thrips are amongst the most important. A key step in the design of control methods is accurate species identification. Despite this, formal reports on species diversity of thrips in Mexico are very scarce. Morphological identification can sometimes be time-consuming and inconclusive. Therefore, we explored the species diversity of thrips in Mexican avocado orchards(Michoacan state) based on partial sequences of the mitochondrial gene cytochrome oxidase subunit Ⅰ(COⅠ). Forty-four specimens were analysed, which represented approximately 8% of all individuals collected from five localities distributed in three Municipalities. All specimens were analysed using the COⅠ marker, and specimens within the genera Frankliniella were also analysed using a marker within the D2 domain of the 28 S(28 SD2) nuclear ribosomal DNA. Molecular identifications were confirmed using morphological taxonomy. Overall, six genera were found(Neohydatothrips, Scirtothrips, Frankliniella, Arorathrips, Caliothrips and Leptothrips). All genera contained only one species, except Frankliniella, for which there were six species. Data from the two molecular markers suggest the existence of cryptic species within Mexican F. occidentalis populations.  相似文献   

7.
[Objective] Study on the genetic diversity in wild populations of Poacynum hendersonii.[Method] Random amplified polymorphic DNA(RAPD)technique was employed to analyze the genetic diversity in five wild populations of P.hendersonii sampled from Xinjiang,Gansu and Qinghai provinces.[Result] Totally 165 clear and repeatable bands were generated in RAPD reaction by using 20 primers screened from 80 primers,of which 110 were polymorphic,accounting for 66.67%.At species level,Nei’s gene diversity index(H),Shannon’s information index(I)and genetic differentiation coefficient(Gst)were 0.220 5,0.304 7 and 0.908 2,respectively.P.hendersonii germplasm resources share a high level of genetic diversity,and genetic differentiation mainly exists among the populations.Results from genetic distances and cluster analysis showed that relationships among P.hendersonii populations were to some extent related with their geographical and climatic characters.[Conclusion] This study suggests that the conservation of P.hendersonii should focus on the protection of many populations,particularly the Qinghai population.  相似文献   

8.
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9.
[Objective] Study on the genetic diversity in wild populations of Poacynum hendersonii.[Method] Random amplified polymorphic DNA(RAPD)technique was employed to analyze the genetic diversity in five wild populations of P.hendersonii sampled from Xinjiang,Gansu and Qinghai provinces.[Result] Totally 165 clear and repeatable bands were generated in RAPD reaction by using 20 primers screened from 80 primers,of which 110 were polymorphic,accounting for 66.67%.At species level,Nei's gene diversity index(H),Shannon's information index(I)and genetic differentiation coefficient(Gst)were 0.220 5,0.304 7 and 0.908 2,respectively.P.hendersonii germplasm resources share a high level of genetic diversity,and genetic differentiation mainly exists among the populations.Results from genetic distances and cluster analysis showed that relationships among P.hendersonii populations were to some extent related with their geographical and climatic characters.[Conclusion] This study suggests that the conservation of P.hendersonii should focus on the protection of many populations,particularly the Qinghai population.  相似文献   

10.
[Objective] Study on the genetic diversity in wild populations of Poacynum hendersonii.[Method] Random amplified polymorphic DNA(RAPD)technique was employed to analyze the genetic diversity in five wild populations of P.hendersonii sampled from Xinjiang,Gansu and Qinghai provinces.[Result] Totally 165 clear and repeatable bands were generated in RAPD reaction by using 20 primers screened from 80 primers,of which 110 were polymorphic,accounting for 66.67%.At species level,Nei's gene diversity index(H),Shannon's information index(I)and genetic differentiation coefficient(Gst)were 0.220 5,0.304 7 and 0.908 2,respectively.P.hendersonii germplasm resources share a high level of genetic diversity,and genetic differentiation mainly exists among the populations.Results from genetic distances and cluster analysis showed that relationships among P.hendersonii populations were to some extent related with their geographical and climatic characters.[Conclusion] This study suggests that the conservation of P.hendersonii should focus on the protection of many populations,particularly the Qinghai population.  相似文献   

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