Karst rocky desertification is a geo-ecological problem in Southwest China. The rocky desertification risk zone delineation could be used as a guide for the regional and hierarchical rocky desertification management a...Karst rocky desertification is a geo-ecological problem in Southwest China. The rocky desertification risk zone delineation could be used as a guide for the regional and hierarchical rocky desertification management and prevention. We chose the middle and lower reaches of the Houzhai underground basin on the karst plateau in Puding County, Guizhou Province, China as the study area and selected land use type, elevation, slope, aspect, lithology and settlement buffer as the main driving factors of the rocky desertification. The potential risk of rocky desertification was quantifed with the factor-weights union method and statistical analysis method. Five grades of rocky desertification risk were delineated based on Geographic Information System. The extremely low, low, moderate, high and extremely high rocky desertification risk zones accounted for 5.01%, 44.17%, 33.92%, 15.59% and 1.30%, respectively. As a whole, the rocky desertification risk level was moderate because the area of low and moderate rocky desertification risk zones occupied 78.09% of the study area. However, more than half of the area （about 50.81%） was predicted to have moderate rocky desertification risk and above, indicating that the study area was subject to rocky desertification. Rocky desertification risk was higher in the southeast and lower in the northwest of the study area. Distinct differences in the distribution of rocky desertification risk zones corresponding to different factors have been found.展开更多
The anthropogenic managements of forest have created a network of roads resulting in the loss and alternation of habitat. To better understand road′s impact on animal habitats, we assessed the habitat pattern of sabl...The anthropogenic managements of forest have created a network of roads resulting in the loss and alternation of habitat. To better understand road′s impact on animal habitats, we assessed the habitat pattern of sables(Martes zibellina), one of rodents within national first-class protected species, when roads are considered in Huzhong area in Da Hinggan Mountains, northeastern China. Employing published literatures about behavior ecology, aerial photographs and forest stand maps, we classified the study area into three habitat types including best-suitable, suitable and unsuitable habitats based on sable habitat requirements at the landscape scale including four variables derived from forest source map with attribute database. Results indicated the loss and significant fragmentation of best-suitable habitat and home range habitat when roads, especially 150 m avoidance distance of roads, were considered. The roads reduced and fragmented highly suitable habitats more significantly during earlier development period than the later development period. Additionally, the suitable area percentage increased with increasing distance to roads. This study helped to identify the suitable area for sables and location of sable population. Also, this study suggested the passage construction and road management involving road closure and removal will reduce the fragmentation functionally and benefit the sable population.展开更多
Alfisols are important soils in China.They occupy about 1.25 million km^(2),or about 13%of the land area.In the current Chinese system of soil classification,burozem,yellow-brown earths,Baijiang(Planosol)soils and par...Alfisols are important soils in China.They occupy about 1.25 million km^(2),or about 13%of the land area.In the current Chinese system of soil classification,burozem,yellow-brown earths,Baijiang(Planosol)soils and parts of drab soils.They are mostly forested soils with an estimated 5-13 t/ha·yr of organic matter returned to the soils from temperate mixed conifer and broad-leaved forest.In terms of elemental bio-cycling,Ca is prominent.In a comparison of 30 profiles the average ratio of clay(B/A)was 1.47 for Cryoboralfs and Eutroboralfs;1.88 for Hapludaifs and 2.53 for Paleudalfs.From Eutroboralfs to Paleudalfs the average gain(or loss)in clay during soil development is about a factor of seven.The moisture regimes vary considerably between Hapludaifs,Cryoboralfs,and associated Cryaquepts,but the amount of water is always enough to cause significant leaching.In the weathering,and pedogenesis processes TiO_(2),MgO and Fe_(2)O_(3) are accumulated,respectively,in both A and BA horizons;but SiO_(2) and Al_(2)O_(3) tend to be leached from the solum.展开更多
Application scope of geostatistics has been gradually extended from original geologic field to soil science and ecological field, etc. and its successful application results have been widely demonstrated. But little i...Application scope of geostatistics has been gradually extended from original geologic field to soil science and ecological field, etc. and its successful application results have been widely demonstrated. But little information is reported as to the direct use of geostatistical method to work out the distribu- tion map of groundwater characteristics. In this paper the semivariogram of geostatistics, in combina- tion with GIS, was used to quantitatively study the spatial variation characteristics of groundwater table depth and mineralization degree and their relation to the landuse changes. F test of the used spherical model reached a very significant level, and the theoretical model can well reflect the spatial structural characteristics of groundwater table depth and mineralization degree and achieve an ideal result. This shows that the application of the method in the dynamical simulation of groundwater is feasible. And this paper also provides useful reference for the application of geostatistics in the study of the dy- namical variations of groundwater resources in the oasis.展开更多
基金Under the auspices of Major Basic Reseach Development Program of China (973 Program) (No. 2006CB403201)
文摘Karst rocky desertification is a geo-ecological problem in Southwest China. The rocky desertification risk zone delineation could be used as a guide for the regional and hierarchical rocky desertification management and prevention. We chose the middle and lower reaches of the Houzhai underground basin on the karst plateau in Puding County, Guizhou Province, China as the study area and selected land use type, elevation, slope, aspect, lithology and settlement buffer as the main driving factors of the rocky desertification. The potential risk of rocky desertification was quantifed with the factor-weights union method and statistical analysis method. Five grades of rocky desertification risk were delineated based on Geographic Information System. The extremely low, low, moderate, high and extremely high rocky desertification risk zones accounted for 5.01%, 44.17%, 33.92%, 15.59% and 1.30%, respectively. As a whole, the rocky desertification risk level was moderate because the area of low and moderate rocky desertification risk zones occupied 78.09% of the study area. However, more than half of the area （about 50.81%） was predicted to have moderate rocky desertification risk and above, indicating that the study area was subject to rocky desertification. Rocky desertification risk was higher in the southeast and lower in the northwest of the study area. Distinct differences in the distribution of rocky desertification risk zones corresponding to different factors have been found.
基金Under the auspices of National Natural Science Foundation of China(No.41271201,31070422,41201185)
文摘The anthropogenic managements of forest have created a network of roads resulting in the loss and alternation of habitat. To better understand road′s impact on animal habitats, we assessed the habitat pattern of sables(Martes zibellina), one of rodents within national first-class protected species, when roads are considered in Huzhong area in Da Hinggan Mountains, northeastern China. Employing published literatures about behavior ecology, aerial photographs and forest stand maps, we classified the study area into three habitat types including best-suitable, suitable and unsuitable habitats based on sable habitat requirements at the landscape scale including four variables derived from forest source map with attribute database. Results indicated the loss and significant fragmentation of best-suitable habitat and home range habitat when roads, especially 150 m avoidance distance of roads, were considered. The roads reduced and fragmented highly suitable habitats more significantly during earlier development period than the later development period. Additionally, the suitable area percentage increased with increasing distance to roads. This study helped to identify the suitable area for sables and location of sable population. Also, this study suggested the passage construction and road management involving road closure and removal will reduce the fragmentation functionally and benefit the sable population.
文摘Alfisols are important soils in China.They occupy about 1.25 million km^(2),or about 13%of the land area.In the current Chinese system of soil classification,burozem,yellow-brown earths,Baijiang(Planosol)soils and parts of drab soils.They are mostly forested soils with an estimated 5-13 t/ha·yr of organic matter returned to the soils from temperate mixed conifer and broad-leaved forest.In terms of elemental bio-cycling,Ca is prominent.In a comparison of 30 profiles the average ratio of clay(B/A)was 1.47 for Cryoboralfs and Eutroboralfs;1.88 for Hapludaifs and 2.53 for Paleudalfs.From Eutroboralfs to Paleudalfs the average gain(or loss)in clay during soil development is about a factor of seven.The moisture regimes vary considerably between Hapludaifs,Cryoboralfs,and associated Cryaquepts,but the amount of water is always enough to cause significant leaching.In the weathering,and pedogenesis processes TiO_(2),MgO and Fe_(2)O_(3) are accumulated,respectively,in both A and BA horizons;but SiO_(2) and Al_(2)O_(3) tend to be leached from the solum.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 90102004 and 40501068).
文摘Application scope of geostatistics has been gradually extended from original geologic field to soil science and ecological field, etc. and its successful application results have been widely demonstrated. But little information is reported as to the direct use of geostatistical method to work out the distribu- tion map of groundwater characteristics. In this paper the semivariogram of geostatistics, in combina- tion with GIS, was used to quantitatively study the spatial variation characteristics of groundwater table depth and mineralization degree and their relation to the landuse changes. F test of the used spherical model reached a very significant level, and the theoretical model can well reflect the spatial structural characteristics of groundwater table depth and mineralization degree and achieve an ideal result. This shows that the application of the method in the dynamical simulation of groundwater is feasible. And this paper also provides useful reference for the application of geostatistics in the study of the dy- namical variations of groundwater resources in the oasis.
