Growth and competition of 14 herb species were investigated in the experimental microcoenosiums in laboratory under the following environmental factors and treatment levels: high and low fertility, clipping and un-cli...Growth and competition of 14 herb species were investigated in the experimental microcoenosiums in laboratory under the following environmental factors and treatment levels: high and low fertility, clipping and un-clipping, and with and without microbial infusion. The most intense competition and the biggest difference in biomass among the species were detected in the high fertility microcoenosiums subjected to no clipping disturbance. Clippings or low fertility reduced the growth of the competitors and resulted in more even biomass distribution among the species. Successive clippings reduced the total accumulative biomass of the microcoenosiums. Microbial infusion significantly increased the growth of legume species Lotus corniculatus L. and Trifolium pratense L. The growth of Alopecurus pratensis L. was also raised by microbial infusion, whereas Dactylis glomerata L. had more biomass in without-microbial-infusion microcoenosiums than in microbial infusion ones. Most of the 14 species were not obviously affected. The positive effect of microbial infusion was more marked in the low fertility microcoenosiums.展开更多
The vegetation of alpine tundra in the Changbai Mountains has experienced great changes in recent decades. Narrowleaf small reed(Deyeuxia angustifolia), a perennial herb from the birch forest zone had crossed the tree...The vegetation of alpine tundra in the Changbai Mountains has experienced great changes in recent decades. Narrowleaf small reed(Deyeuxia angustifolia), a perennial herb from the birch forest zone had crossed the tree line and invaded into the alpine tundra zone. To reveal the driven mechanism of D. angustifolia invasion, there is an urgent need to figure out the effective seed distribution pattern, which could tell us where the potential risk regions are and help us to interpret the invasion process. In this study, we focus on the locations of the seeds in the soil layer and mean to characterize the effective seed distribution pattern of D. angustifolia. The relationship between the environmental variables and the effective seed distribution pattern was also assessed by redundancy analysis. Results showed that seeds of D. angustifolia spread in the alpine tundra with a considerable number(mean value of 322 per m2). They were mainly distributed in the low elevation areas with no significant differences in different slope positions. Effective seed number(ESN) occurrences of D. angustifolia were different in various plant communities. Plant communities with lower canopy cover tended to have more seeds of D. angustifolia. Our research indicated reliable quantitative information on the extent to which habitats are susceptible to invasion.展开更多
文摘Growth and competition of 14 herb species were investigated in the experimental microcoenosiums in laboratory under the following environmental factors and treatment levels: high and low fertility, clipping and un-clipping, and with and without microbial infusion. The most intense competition and the biggest difference in biomass among the species were detected in the high fertility microcoenosiums subjected to no clipping disturbance. Clippings or low fertility reduced the growth of the competitors and resulted in more even biomass distribution among the species. Successive clippings reduced the total accumulative biomass of the microcoenosiums. Microbial infusion significantly increased the growth of legume species Lotus corniculatus L. and Trifolium pratense L. The growth of Alopecurus pratensis L. was also raised by microbial infusion, whereas Dactylis glomerata L. had more biomass in without-microbial-infusion microcoenosiums than in microbial infusion ones. Most of the 14 species were not obviously affected. The positive effect of microbial infusion was more marked in the low fertility microcoenosiums.
基金Special Fund of National Seismological Bureau,China(No.201208005)Doctorial Innovation Fund of Northeast Normal University(No.10SSXT133,2412013XS001)+1 种基金National Natural Science Foundation of China(No.41171038,41171072,41101523)Doctoral Fund of Ministry of Education of China(No.20120043110014)
文摘The vegetation of alpine tundra in the Changbai Mountains has experienced great changes in recent decades. Narrowleaf small reed(Deyeuxia angustifolia), a perennial herb from the birch forest zone had crossed the tree line and invaded into the alpine tundra zone. To reveal the driven mechanism of D. angustifolia invasion, there is an urgent need to figure out the effective seed distribution pattern, which could tell us where the potential risk regions are and help us to interpret the invasion process. In this study, we focus on the locations of the seeds in the soil layer and mean to characterize the effective seed distribution pattern of D. angustifolia. The relationship between the environmental variables and the effective seed distribution pattern was also assessed by redundancy analysis. Results showed that seeds of D. angustifolia spread in the alpine tundra with a considerable number(mean value of 322 per m2). They were mainly distributed in the low elevation areas with no significant differences in different slope positions. Effective seed number(ESN) occurrences of D. angustifolia were different in various plant communities. Plant communities with lower canopy cover tended to have more seeds of D. angustifolia. Our research indicated reliable quantitative information on the extent to which habitats are susceptible to invasion.
