Soil microorganisms are important components of soil ecosystem and play central roles in biogeochemical cycling such as organic matter decomposition, mineral nutrient release, and energy transformation. Along with the intensive comprehension of the importance of biodiversity and the rapid development of methodology, more and more studies have focused on soil microbial diversity. This review introduces the current development of methodology and affecting factors of soil microbial diversity. We also discussed the directions of future research on soil microbial diversity.
Tree mortality, usually resulting from interactions among multiple factors, is a crucial process in forest dynamics. Using two census datasets (2004 and 2009) from a 25 ha plot in the Changbai Mountains, we analyzed the composition, size class structure and spatial distribution of individual trees (DBH ≥ 1 cm) that died during the 5-year period. The number of species went from 52 in 2004 to 51 in 2009, with 3 species disappearing and 2 others appearing. The number of individuals changed from 36,908 to 34,926, with 4,030 dying and 2,048 being recruited. The number of dead individuals accounted for 10.9% of total individuals in 2004. Species with high mortality also tended to have high recruitment. Compared with tree species, shrub species had both higher mortality and recruitment rates. In addition, 44 species showed an increased mean DBH in 2009, while the mean DBH of 5 other species decreased. Mortality decreased as DBH increased. Size class distributions of dead dominant species in different vertical layers were similar in the two censuses. Spatial distributions of dead individuals were species-specific. Dead individuals from smaller size classes were spatially clumped at small scales and became randomly spaced at larger scales. However, dead individuals from larger size classes tended to show random distribution at various scales.
Evergreen broad-leaved forest (EBLF) is a typical vegetation type in low elevation regions in eastern China. The permanent plot-based approach to community analysis is fundamentally important for revealing mechanisms of biodiversity maintenance. In this study, community structure and species composition were investigated and analyzed using a 20-ha permanent plot in Tiantong National Forest Park, Zhejiang Province. Our results were as follows: (1) we counted a total of 94,603 individuals, belonging to 152 species, 94 genera and 51 families. The three most dominant families were Theaceae, Lauraceae and Fagaceae. The genera present were dominated by tropical (52.1% in total) and temperate (42.6% in total) floras; (2) species in the evergreen life form were dominant with a community importance value of 80.3%. The three most dominant species were Eurya loquaiana, Litsea elongata and Choerospondias axiliaris. Fifty five species were considered rare; (3) the size distribution of all trees followed a reverse “J” shape; and (4) evergreen species showed a greater resprouting ability than deciduous species. In conclusion, with rich species composition and a mature community structure, the EBLF in Tiantong region is typical of this vegetation type.
To explore the status of macrozoobenthic communities and their response to ecological changes in Lake Taihu, we carried out a quarterly investigation on macrozoobenthos between February 2007 and November 2008. We recorded 40 species from 19 families, 7 classes and 3 phyla. Mean density and biomass varied largely among the 30 sampling sites. The highest mean density of macrozoobenthos occurred in Meiliang Bay, Zhushan Bay and river mouth, and communities were dominated by Tubificidae. Mean biomass was highest in Gonghu Bay, Western region, East Taihu and East Bays, these sites were dominated by Mollusca. Limnodrilus hoffmeisteri, Rhyacodrilus sinicus, Corbicula fluminea, Bellamya aeruginosa, Tanypus chinensis and Gammarus sp. were the dominant species in Lake Taihu. Cluster analysis and one-way analysis of similarity (ANOSIM) classified the 30 sites into three groups with different macrozoobenthic communities (P < 0.05). K-dominance curves, Shannon-Wiener and Pielou indices indicated that species richness and evenness were highest in East Taihu and East Bays, dominated by Gastropods. Communities in Meiliang Bay, Zhushan Bay and river mouth had low species diversity and were dominated by L. hoffmeisteri and R. sinicus. Gonghu Bay, Central region and Western region contained intermediately diverse communities dominated by C. fluminea. Our results suggest that trophic status, habitat types and macrophytes are impor-tant factors regulating macrozoobenthic communities in Lake Taihu.
Biodiversity Committee, CAS
Botanical Society of China
Institute of Botany, CAS
Institute of Zoology, CAS
Institute of Microbiology, CAS
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