Rehabilitation(amendment and vegetation establishment)on bauxite residue is viewed as a promising strategy to stabilize the surface and initiate soil development.However,such approaches are inhibited by high pH,high e...Rehabilitation(amendment and vegetation establishment)on bauxite residue is viewed as a promising strategy to stabilize the surface and initiate soil development.However,such approaches are inhibited by high pH,high exchangeable sodium(ESP)and poor nutrient status.Amendment with gypsum is effective in improving residue physical and chemical properties and promoting seed establishment and growth.Application of organics(e.g.compost)can address nutrient deficiencies but supplemental fertilizer additions may be required.A series of germination bioassays were performed on residue to determine candidate species and optimum rehabilitation application rates.Subsequent field trials assessed establishment of grassland species Holcus lanatus and Trifolium pratense as well as physical and chemical properties of amended residue.Follow up monitoring over five years assessed elemental content in grassland and species dynamics.With co-application of the amendments several grassland species can grow on the residue.Over time other plant species can invade the restored area and fast growing nutrient demanding grasses are replaced.Scrub species can establish within a 5 Yr period and there is evidence of nutrient cycling.High pH,sodicity and nutrient deficiencies are the major limiting factors to establishing grassland on residue.Following restoration several plant species can grow on amended residue.展开更多
The area around the oasis, lying between the oasis and the natural desert and encirclesthe oasis is different from ecotone of the oasis and the desert, because it is not the trans-forming area betwen them, but it is e...The area around the oasis, lying between the oasis and the natural desert and encirclesthe oasis is different from ecotone of the oasis and the desert, because it is not the trans-forming area betwen them, but it is ecological rift valley or ecological burst zone. The oasisbase will be shaked and the nature desert will be degenerative too. It is the crux of the envi-展开更多
Shrub-grass vegetation was established on the rocky slope of Longhui-Dongkou Section of Shaohuai Expressway (Shaoyang to Huaihua) by following the below procedures: ① According to regional climatic characteristics, g...Shrub-grass vegetation was established on the rocky slope of Longhui-Dongkou Section of Shaohuai Expressway (Shaoyang to Huaihua) by following the below procedures: ① According to regional climatic characteristics, grasses like Cynodon dactylon, Papalum natatum and Sorghum bicolor (L.) Moench can be applied as pioneering species, local shrubs with drought, cold and infertility resistance like Nerium ndicum Mill., Amorpha fruticosa, Pyracantha fortuneana, and Mycoplasma organism as constructive species, local arbors like Robinia pseudoacacia and Albizia kalkora as accompanying species; ② Slope should be treated first before the establishment of shrub-grass vegetation, then anchored, and covered with nets after the mortar solidified and hardened; after the base materials spraying which includes both substrate spraying and surface spraying, the slope should be promptly covered with non-woven fabrics. The results showed that green coverage ratio of shrub-grass vegetation achieved 90% or above, all quality indexes met the expected standards, which implied that the establishment of shrub-grass vegetation is a rapid and effective way for the vegetation restoration of rocky slopes along expressways, and worth of being promoted in similar climatic zones.展开更多
In Dynamic Global Vegetation Models （DGVMs）, the establishment of woody vegetation refers to flowering, fertiliza- tion, seed production, germination, and the growth of tree seedlings. It determines not only the pop...In Dynamic Global Vegetation Models （DGVMs）, the establishment of woody vegetation refers to flowering, fertiliza- tion, seed production, germination, and the growth of tree seedlings. It determines not only the population densities but also other important ecosystem structural variables. In current DGVMs, establishments of woody plant functional types （PFTs） are assumed to be either the same in the same grid cell, or largely stochastic. We investigated the uncertainties in the competition of establishment among coexisting woody PFTs from three aspects： the dependence of PFT establishments on vegetation states; background establishment; and relative establishment potentials of different PFTs. Sensitivity experi- ments showed that the dependence of establishment rate on the fractional coverage of a PFT favored the dominant PFT by increasing its share in establishment. While a small background establishment rate had little impact on equilibrium states of the ecosystem, it did change the timescale required for the establishment of alien species in pre-existing forest due to their disadvantage in seed competition during the early stage of invasion. Meanwhile, establishment purely fiom background （the scheme commonly used in current DGVMs） led to inconsistent behavior in response to the change in PFT specification （e.g., number of PFTs and their specification）. Furthermore, the results also indicated that trade-off between irtdividual growth and reproduction/colonization has significant influences on the competition of establishment. Hence, further development of es- tablishment parameterization in DGVMs is essential in reducing the uncertainties in simulations of both ecosystem structures and successions.展开更多
基金Projects(41877551,41842020)supported by the National Natural Science Foundation of ChinaProject supported by the Science Foundation Ireland 17/CDA/4778
文摘Rehabilitation(amendment and vegetation establishment)on bauxite residue is viewed as a promising strategy to stabilize the surface and initiate soil development.However,such approaches are inhibited by high pH,high exchangeable sodium(ESP)and poor nutrient status.Amendment with gypsum is effective in improving residue physical and chemical properties and promoting seed establishment and growth.Application of organics(e.g.compost)can address nutrient deficiencies but supplemental fertilizer additions may be required.A series of germination bioassays were performed on residue to determine candidate species and optimum rehabilitation application rates.Subsequent field trials assessed establishment of grassland species Holcus lanatus and Trifolium pratense as well as physical and chemical properties of amended residue.Follow up monitoring over five years assessed elemental content in grassland and species dynamics.With co-application of the amendments several grassland species can grow on the residue.Over time other plant species can invade the restored area and fast growing nutrient demanding grasses are replaced.Scrub species can establish within a 5 Yr period and there is evidence of nutrient cycling.High pH,sodicity and nutrient deficiencies are the major limiting factors to establishing grassland on residue.Following restoration several plant species can grow on amended residue.
文摘The area around the oasis, lying between the oasis and the natural desert and encirclesthe oasis is different from ecotone of the oasis and the desert, because it is not the trans-forming area betwen them, but it is ecological rift valley or ecological burst zone. The oasisbase will be shaked and the nature desert will be degenerative too. It is the crux of the envi-
基金Supported by 948 Key Projects of State Forestry Administration (2008-4-32)~~
文摘Shrub-grass vegetation was established on the rocky slope of Longhui-Dongkou Section of Shaohuai Expressway (Shaoyang to Huaihua) by following the below procedures: ① According to regional climatic characteristics, grasses like Cynodon dactylon, Papalum natatum and Sorghum bicolor (L.) Moench can be applied as pioneering species, local shrubs with drought, cold and infertility resistance like Nerium ndicum Mill., Amorpha fruticosa, Pyracantha fortuneana, and Mycoplasma organism as constructive species, local arbors like Robinia pseudoacacia and Albizia kalkora as accompanying species; ② Slope should be treated first before the establishment of shrub-grass vegetation, then anchored, and covered with nets after the mortar solidified and hardened; after the base materials spraying which includes both substrate spraying and surface spraying, the slope should be promptly covered with non-woven fabrics. The results showed that green coverage ratio of shrub-grass vegetation achieved 90% or above, all quality indexes met the expected standards, which implied that the establishment of shrub-grass vegetation is a rapid and effective way for the vegetation restoration of rocky slopes along expressways, and worth of being promoted in similar climatic zones.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA05110103)the State Key Project for Basic Research Program of China(Grant No.2010CB951801)the National High Technology Research and Development Program of China(863 Program)(Grant No.2009AA122105)
文摘In Dynamic Global Vegetation Models （DGVMs）, the establishment of woody vegetation refers to flowering, fertiliza- tion, seed production, germination, and the growth of tree seedlings. It determines not only the population densities but also other important ecosystem structural variables. In current DGVMs, establishments of woody plant functional types （PFTs） are assumed to be either the same in the same grid cell, or largely stochastic. We investigated the uncertainties in the competition of establishment among coexisting woody PFTs from three aspects： the dependence of PFT establishments on vegetation states; background establishment; and relative establishment potentials of different PFTs. Sensitivity experi- ments showed that the dependence of establishment rate on the fractional coverage of a PFT favored the dominant PFT by increasing its share in establishment. While a small background establishment rate had little impact on equilibrium states of the ecosystem, it did change the timescale required for the establishment of alien species in pre-existing forest due to their disadvantage in seed competition during the early stage of invasion. Meanwhile, establishment purely fiom background （the scheme commonly used in current DGVMs） led to inconsistent behavior in response to the change in PFT specification （e.g., number of PFTs and their specification）. Furthermore, the results also indicated that trade-off between irtdividual growth and reproduction/colonization has significant influences on the competition of establishment. Hence, further development of es- tablishment parameterization in DGVMs is essential in reducing the uncertainties in simulations of both ecosystem structures and successions.
