An investigation was conducted on distribution pattern, site condition and population structure of yew Taxus cuspidata Sieb. et Zucc. in Muling Forest Bureau of Heilongjiang Province, China in April, 2005. Results sho...An investigation was conducted on distribution pattern, site condition and population structure of yew Taxus cuspidata Sieb. et Zucc. in Muling Forest Bureau of Heilongjiang Province, China in April, 2005. Results showed that yew is mainly distributed under the main storey of natural mixed forest of conifer and broadleaf, the soil moisture content of the yew site is high （40%-60%）, the pH value of soil is relatively lower （4.7-5.5）, and that the population structure of wild yew is not rational, belonging to the degeneration population, which is one of the reasons leading to the population decline. Although the site conditions of Muling area are suitable for the growth of wild yew, the population of wild yew shows a decline tendency, due to the fact that the middle-sized adult yew trees have been cut, young yews are often grazed by wildlife, and that the trunks of adult yew tend to be hollow.展开更多
Understanding population structure provides basic ecological data related to species and ecosystems.Our objective was to understand the mechanisms involved in the maintenance of Quercus aquifolioides populations.Using...Understanding population structure provides basic ecological data related to species and ecosystems.Our objective was to understand the mechanisms involved in the maintenance of Quercus aquifolioides populations.Using a 1 ha permanent sample plot data for Q.aquifolioides on Sejila Mountain,Tibet Autonomous Region(Tibet),China,we analyzed the population structure of Q.aquifolioides by combining data for diameter class,static life table and survival curve.Simultaneously,the spatial distribution of Q.aquifolioides was studied using Ripley’s L Function in point pattern analysis.The results showed:(1) Individuals in Q.aquifolioides populations were mainly aggregated in the youngest age classes,that accounted for94.3% of the individuals; the older age classes had much smaller populations.Although the youngest age classes(ClassesⅠ and Ⅱ) had fewer individuals than Class Ⅲ,the total number of individuals in classes Ⅰ and Ⅱ was also greater than in classes Ⅳ to Ⅸ.In terms of tree height,fewsaplings,more medium-sized saplings and few large-sized trees were found.The diameter class structure of Q.aquifolioides populations formed an atypical ‘pyramid’type; the population was expanding,but growth was limited,tending toward a stable population.(2) Mortality of Q.aquifolioides increased continuously with age; life expectancy decreased over time,and the survivorship curve was close to a Deevey I curve.(3) The spatial distribution pattern of Q.aquifolioides varied widely across different developmental stages.Saplings and medium-sized tree showed aggregated distributions at the scales of 0–33 m and 0–29 m,respectively.The aggregation intensities of saplings and medium-sized trees at small scales were significantly stronger than that of large-sized trees.However,large-sized trees showed a random distribution at most scales.(4) No correlation was observed among saplings,medium-and large-sized trees at small scales,while a significant and negative association was observed as the scale increased.Strong competition was found among saplings,medium-and large-sized trees,while no significant association was observed between medium-and largesized trees at all scales.Biotic interactions and local ecological characteristics influenced the spatial distribution pattern of Q.aquifolioides populations most strongly.展开更多
Direction-dependence,or anisotropy,of spatial distribution patterns of vegetation is rarely explored due to neglect of this ecological phenomenon and the paucity of methods dealing with this issue.This paper proposes ...Direction-dependence,or anisotropy,of spatial distribution patterns of vegetation is rarely explored due to neglect of this ecological phenomenon and the paucity of methods dealing with this issue.This paper proposes a new approach to anisotropy analysis of spatial distribution patterns of plant populations on the basis of the data resam-pling technique(DRT)combined with Ripley’s L index.Using the ArcView Geographic Information System(GIS)platform,a case study was carried out by selecting the popula-tion of Pinus massoniana from a needle-and broad-leaved mixed forest community in the Heishiding Nature Reserve,Guangdong Province.Results showed that the spatial pattern of the P.massoniana population was typically anisotropic with different patterns in different directions.The DRT was found to be an effective approach to the anisotropy analysis of spatial patterns of plant populations.By employing resam-pling sub-datasets from the original dataset in different direc-tions,we could overcome the difficulty in the direct use of current non-angular methods of pattern analysis.展开更多
The population size class structure, survival curve, height class structure and population distribution patterns of Ilex cornuta in Longgan Lake National Nature Preserve, Hubei Province, were investigated by using the...The population size class structure, survival curve, height class structure and population distribution patterns of Ilex cornuta in Longgan Lake National Nature Preserve, Hubei Province, were investigated by using the adjacent grid method. The result showed that the population age structure of I. cornuta was of middle-aging type, in the vertical space of population individuals, most of them lived in the shrub layer, and a small number of individuals entered the arborous layer. The distribution pattern of I. cornuta was analyzed by variance /mean ratio method, and the results showed that the distribution pattern of the population was the cluster type. This study can provide references for the further protection, research and development and utilization of I. cornuta .展开更多
文摘An investigation was conducted on distribution pattern, site condition and population structure of yew Taxus cuspidata Sieb. et Zucc. in Muling Forest Bureau of Heilongjiang Province, China in April, 2005. Results showed that yew is mainly distributed under the main storey of natural mixed forest of conifer and broadleaf, the soil moisture content of the yew site is high （40%-60%）, the pH value of soil is relatively lower （4.7-5.5）, and that the population structure of wild yew is not rational, belonging to the degeneration population, which is one of the reasons leading to the population decline. Although the site conditions of Muling area are suitable for the growth of wild yew, the population of wild yew shows a decline tendency, due to the fact that the middle-sized adult yew trees have been cut, young yews are often grazed by wildlife, and that the trunks of adult yew tend to be hollow.
基金financially supported by the National Key Technology Support Program(Grant No.2013BAC04B01)the National Natural Science Foundation of China(Grant No.31460200)
文摘Understanding population structure provides basic ecological data related to species and ecosystems.Our objective was to understand the mechanisms involved in the maintenance of Quercus aquifolioides populations.Using a 1 ha permanent sample plot data for Q.aquifolioides on Sejila Mountain,Tibet Autonomous Region(Tibet),China,we analyzed the population structure of Q.aquifolioides by combining data for diameter class,static life table and survival curve.Simultaneously,the spatial distribution of Q.aquifolioides was studied using Ripley’s L Function in point pattern analysis.The results showed:(1) Individuals in Q.aquifolioides populations were mainly aggregated in the youngest age classes,that accounted for94.3% of the individuals; the older age classes had much smaller populations.Although the youngest age classes(ClassesⅠ and Ⅱ) had fewer individuals than Class Ⅲ,the total number of individuals in classes Ⅰ and Ⅱ was also greater than in classes Ⅳ to Ⅸ.In terms of tree height,fewsaplings,more medium-sized saplings and few large-sized trees were found.The diameter class structure of Q.aquifolioides populations formed an atypical ‘pyramid’type; the population was expanding,but growth was limited,tending toward a stable population.(2) Mortality of Q.aquifolioides increased continuously with age; life expectancy decreased over time,and the survivorship curve was close to a Deevey I curve.(3) The spatial distribution pattern of Q.aquifolioides varied widely across different developmental stages.Saplings and medium-sized tree showed aggregated distributions at the scales of 0–33 m and 0–29 m,respectively.The aggregation intensities of saplings and medium-sized trees at small scales were significantly stronger than that of large-sized trees.However,large-sized trees showed a random distribution at most scales.(4) No correlation was observed among saplings,medium-and large-sized trees at small scales,while a significant and negative association was observed as the scale increased.Strong competition was found among saplings,medium-and large-sized trees,while no significant association was observed between medium-and largesized trees at all scales.Biotic interactions and local ecological characteristics influenced the spatial distribution pattern of Q.aquifolioides populations most strongly.
基金This paper was supported by the National Natural Science Foundation of China(Grant No.30370254).
文摘Direction-dependence,or anisotropy,of spatial distribution patterns of vegetation is rarely explored due to neglect of this ecological phenomenon and the paucity of methods dealing with this issue.This paper proposes a new approach to anisotropy analysis of spatial distribution patterns of plant populations on the basis of the data resam-pling technique(DRT)combined with Ripley’s L index.Using the ArcView Geographic Information System(GIS)platform,a case study was carried out by selecting the popula-tion of Pinus massoniana from a needle-and broad-leaved mixed forest community in the Heishiding Nature Reserve,Guangdong Province.Results showed that the spatial pattern of the P.massoniana population was typically anisotropic with different patterns in different directions.The DRT was found to be an effective approach to the anisotropy analysis of spatial patterns of plant populations.By employing resam-pling sub-datasets from the original dataset in different direc-tions,we could overcome the difficulty in the direct use of current non-angular methods of pattern analysis.
基金Supported by the Team Project of Hubei Collaborative Innovation Center for the Characteristic Resources Exploitation of Dabie Mountains(2015TD06)
文摘The population size class structure, survival curve, height class structure and population distribution patterns of Ilex cornuta in Longgan Lake National Nature Preserve, Hubei Province, were investigated by using the adjacent grid method. The result showed that the population age structure of I. cornuta was of middle-aging type, in the vertical space of population individuals, most of them lived in the shrub layer, and a small number of individuals entered the arborous layer. The distribution pattern of I. cornuta was analyzed by variance /mean ratio method, and the results showed that the distribution pattern of the population was the cluster type. This study can provide references for the further protection, research and development and utilization of I. cornuta .
