The distribution characteristics of heavy metals such as Cu, Zn, Pb, Cd, Hg. As in seawater, superficail sediments and several marine organisms of Dongzhai Harbor in Hainan were analyzed. Index methods of the single f...The distribution characteristics of heavy metals such as Cu, Zn, Pb, Cd, Hg. As in seawater, superficail sediments and several marine organisms of Dongzhai Harbor in Hainan were analyzed. Index methods of the single factor and geo-accumulation were used to assess the pollution degree of heavy metals. The results showed that the heavy metal levels in the seawater of Dongzhai Harbor accorded with the first category of the seawater except Pb, and were much lower than the fishery water quality standard; the concentration of the heavy metal in surface sediments did not exceed the national benchmark of the first-class of marine sediment quality basically, and the superficial sediments were essentially uncontaminated; the heavy metal content in wetland sediments was slightly higher than those in other typical mangrove wetland island of Hainan and marine sediments in Dongzhai Haibor, which indicated this area might has been affected by land-based pollution influence, and this should cause the attention of related departments; the heavy metal concentrations in marine organisms were up to the first category. All were not beyond the standard of non-environmental pollution aquatic products.展开更多
Taking Dongzhai Town in Ningwu County of Shanxi Province as example, this essay explores the spatial structure of towns and villages system from the following perspectives: scale structure, function structure, structu...Taking Dongzhai Town in Ningwu County of Shanxi Province as example, this essay explores the spatial structure of towns and villages system from the following perspectives: scale structure, function structure, structural characteristics of village land-use, and spatial distribution characteristics of Dongzhai villages. There are 5 grades of villages according to their scales, that is, villages have a population over 1 000, between 500 and 1 000, between 100 and 500, less than 100, less than 50. The function structure of Dongzhai Town is divided into 3 grades, Grade 1 (core village), is village with such functions as tourist service, transportation and distribution function. Grade 2 (characteristic village), is agricultural settlement with functions such as industrial function, transportation service, tourist service, and forestry function. Grade 3 (general village), is agricultural settlements with prominent agricultural functions (dry farming). This essay also predicts the change and responses of this town based on the population forecast models. It is predicted that the population of Jiancheng District will reach 4 750 in 2010, 6 400 in 2015, 8 700 in 2020. Returning farmland to forests in Fenhe River valley can ensure the conservation of water resources and the development of tourist service. The proportion of forest land, especially bushes land, and proportion of grassland, especially artificial grass will increase dramatically. The number of slope land will be down a bit. The Lands for settlement and transportation will increase with the development of ecological migration and tourist service. Specialized land such as water area and places of interest will skyrocket. Village patterns and spatial distribution under the system of towns and villages will be improved as well.展开更多
Background:The Hair-crested Drongo(Dicrurus hottentottus) exhibits a unique nest-dismantling behavior after the fledging of the young.One hypothesis explaining this behavior is dismantling one's own nest may reduc...Background:The Hair-crested Drongo(Dicrurus hottentottus) exhibits a unique nest-dismantling behavior after the fledging of the young.One hypothesis explaining this behavior is dismantling one's own nest may reduce potential competition for nest sites in the following breeding season because suitable breeding habitat might be limited,and sites are often reused.Methods:By comparing the habitat features at nest and random locations,we determined the nest habitat preference of the Hair-crested Drongo within Dongzhai National Nature Reserve,Henan,China.We also compared habitat features with nesting success to determine if any trends could be detected.Results:We found that nest tree height,diameter at breast height,live crown ratio,tree rank,and presence of overstory were significantly higher at nesting locations than random locations;slope,leaf litter cover percentage and depth,presence of understory and midstory,and number of trees per hectare were significantly lower at nest sites than random sites.Drongos preferred to use some tree species,such as Metasequoia glyptostroboides,Castanea mollissima,and Pterocarya stenoptera for nesting.Failed nests were often associated with habitat with higher percentage of leaf litter on the ground.Conclusion:Our data support that selection of nest sites does occur for this species at this site and therefore support the hypothesis that breeding habitat limitation could be one of the driving forces for the development of the nestdismantling behavior in this species.展开更多
文摘The distribution characteristics of heavy metals such as Cu, Zn, Pb, Cd, Hg. As in seawater, superficail sediments and several marine organisms of Dongzhai Harbor in Hainan were analyzed. Index methods of the single factor and geo-accumulation were used to assess the pollution degree of heavy metals. The results showed that the heavy metal levels in the seawater of Dongzhai Harbor accorded with the first category of the seawater except Pb, and were much lower than the fishery water quality standard; the concentration of the heavy metal in surface sediments did not exceed the national benchmark of the first-class of marine sediment quality basically, and the superficial sediments were essentially uncontaminated; the heavy metal content in wetland sediments was slightly higher than those in other typical mangrove wetland island of Hainan and marine sediments in Dongzhai Haibor, which indicated this area might has been affected by land-based pollution influence, and this should cause the attention of related departments; the heavy metal concentrations in marine organisms were up to the first category. All were not beyond the standard of non-environmental pollution aquatic products.
基金Supported by Soft Science Research Project of Shanxi Province(2008041034-02 )Institutions and Enterprises Entrusted Project(0908045+1 种基金 0908046 0908043)~~
文摘Taking Dongzhai Town in Ningwu County of Shanxi Province as example, this essay explores the spatial structure of towns and villages system from the following perspectives: scale structure, function structure, structural characteristics of village land-use, and spatial distribution characteristics of Dongzhai villages. There are 5 grades of villages according to their scales, that is, villages have a population over 1 000, between 500 and 1 000, between 100 and 500, less than 100, less than 50. The function structure of Dongzhai Town is divided into 3 grades, Grade 1 (core village), is village with such functions as tourist service, transportation and distribution function. Grade 2 (characteristic village), is agricultural settlement with functions such as industrial function, transportation service, tourist service, and forestry function. Grade 3 (general village), is agricultural settlements with prominent agricultural functions (dry farming). This essay also predicts the change and responses of this town based on the population forecast models. It is predicted that the population of Jiancheng District will reach 4 750 in 2010, 6 400 in 2015, 8 700 in 2020. Returning farmland to forests in Fenhe River valley can ensure the conservation of water resources and the development of tourist service. The proportion of forest land, especially bushes land, and proportion of grassland, especially artificial grass will increase dramatically. The number of slope land will be down a bit. The Lands for settlement and transportation will increase with the development of ecological migration and tourist service. Specialized land such as water area and places of interest will skyrocket. Village patterns and spatial distribution under the system of towns and villages will be improved as well.
基金support by Dongzhai National Nature Reserve for conducting this studyFunding and support was provided by National Science Foundation East Asia Pacific Summer Institute (EAPSI)+2 种基金Chinese Ministry of Science and TechnologyChina Science and Technology Exchange Center Further funding and support was provided by Alabama A&M University and Beijing Normal University
文摘Background:The Hair-crested Drongo(Dicrurus hottentottus) exhibits a unique nest-dismantling behavior after the fledging of the young.One hypothesis explaining this behavior is dismantling one's own nest may reduce potential competition for nest sites in the following breeding season because suitable breeding habitat might be limited,and sites are often reused.Methods:By comparing the habitat features at nest and random locations,we determined the nest habitat preference of the Hair-crested Drongo within Dongzhai National Nature Reserve,Henan,China.We also compared habitat features with nesting success to determine if any trends could be detected.Results:We found that nest tree height,diameter at breast height,live crown ratio,tree rank,and presence of overstory were significantly higher at nesting locations than random locations;slope,leaf litter cover percentage and depth,presence of understory and midstory,and number of trees per hectare were significantly lower at nest sites than random sites.Drongos preferred to use some tree species,such as Metasequoia glyptostroboides,Castanea mollissima,and Pterocarya stenoptera for nesting.Failed nests were often associated with habitat with higher percentage of leaf litter on the ground.Conclusion:Our data support that selection of nest sites does occur for this species at this site and therefore support the hypothesis that breeding habitat limitation could be one of the driving forces for the development of the nestdismantling behavior in this species.
