Sixteen different vegetation types of grassland and shrubland were selected to study the component and diversity of plant species of riparian plant communities along main channel in the Three-Gorges areas. Species ric...Sixteen different vegetation types of grassland and shrubland were selected to study the component and diversity of plant species of riparian plant communities along main channel in the Three-Gorges areas. Species richness (s), Simpson index (D), and Shannon-Weiner index (H) were used to study the biodiversity and the hierarchical classification was carried out by the methods of TWINSPAN and DCA ordination. The results showed that the components of flora were complex and dominated by the temperate type in the riparian plant communities. Species diversity was not different between the communities, but Shannon-Weiner indexes of different layers in some grassland were significantly different. TWINSPAN and DCA indicated that riparian plant communities distributed along the gradient of moisture.展开更多
Reclamation of tidal flat is one of the main ways to get a dynamic balance of the total amount of plowland. With the development of social economy and the increasing demand for plowland, the contradiction between tida...Reclamation of tidal flat is one of the main ways to get a dynamic balance of the total amount of plowland. With the development of social economy and the increasing demand for plowland, the contradiction between tidal flat reclamation and environment protection becomes more and more outstanding. However, tidal flat reclamation should also follow the dynamic balance of total amount of tidal flat amount. The paper analyzed the history of reclamation and development of Jiangsu mud coast, and calculated the feasible rates of tidal flat reclamation on different stretches respectively, and pointed out that both the economic social benefits of reclamation and the natural erosion-accretion conditions of the coasts should be taken into consideration in deciding the intensity of tidal flat reclamation, so as to satisfy demands on both reclamation and protection of tidal flat resource.展开更多
Based on the combined hydraulic calculation for the eastern network region at the Pearl River estuary and several outlets to the Lingdingyang Bay, the sediment calculation modelling was introduced in the establishment...Based on the combined hydraulic calculation for the eastern network region at the Pearl River estuary and several outlets to the Lingdingyang Bay, the sediment calculation modelling was introduced in the establishment of the sediment mathematical model for Lingdingyang Bay and the eastern region with one and two dimensional flow calculation. Model adjustment and verification were performed in conjunction with field data. The simulated results coincide well with measured data.In addition the model is applied to predict the shore-line planning scheme of Lingdingyang Bay.The theoretical criterion is provided for the shore line plan in the model.And a new mathematical simulated method is put out to research the planning engineering concerned with one-dimensional net rivers and two-dimensional estuary.展开更多
Feiyantan was the discharge area of Diaokou River distributary of the Yellow River during the period of 1964 to 1976. The coastal erosion feature and morphological evolution at the Feiyantan coast are studied in the l...Feiyantan was the discharge area of Diaokou River distributary of the Yellow River during the period of 1964 to 1976. The coastal erosion feature and morphological evolution at the Feiyantan coast are studied in the light of the topography and section depth, and the corresponding dynamics of wave and current. Results indicate that the protruding topography left after the Diaokou River distributary was abandoned is the main cause of strong coastal erosion. Further research suggests that waves start up the sediment and the tidal current transports it, and the waves and tidal current are combined to be the dominant dynamic mechanism of coastal erosion, in which the tidal residual current takes and transports the sediment outward, thus causing the sediment to wane in the coast.展开更多
Due to the importance of riparian zone in maintaining and protecting regional biodiversity, increasingly more ecologists paid their attentions to riparian zone and had been aware of the important effects of riparian z...Due to the importance of riparian zone in maintaining and protecting regional biodiversity, increasingly more ecologists paid their attentions to riparian zone and had been aware of the important effects of riparian zone in basic study and practical management. In this study, 42 sampling belts (10 m?00 m) parallel to the bank of Xiangxi River at different elevations in Shennongjia Area were selected to investigate the riparian vegetation and rare plants. 14 species of rare plants were found distributing in riparian zone, accounting for 42.4% of the total rare plant species in Shennongjia Area. The main distribution range of the 14 rare plant species was the evergreen and deciduous mixed broadleaved forest at elevation of 1200-1800 m, where, species diversity of plant community was the maximum at the moderate elevation. The analysis of TWINSPAN divided the 14 rare species into 3 groups against the elevation, namely low elevation species group, moderate elevation species group, and high elevation species group. The analysis of DCA ordination showed similar results to that of TWINSPAN. In the paper, the authors discussed the reasons forming the distribution pattern of rare plant species, and pointed out that the important function of riparian zone on rare plant species protection.展开更多
This paper, with NOAA/AHHRR data for 2 years, discusses the expanding path and extent of suspended sediment from the Changjiang River, and the relationship between the suspended sediment expanding and coastal current ...This paper, with NOAA/AHHRR data for 2 years, discusses the expanding path and extent of suspended sediment from the Changjiang River, and the relationship between the suspended sediment expanding and coastal current systems by analyzing the thermal infrared imagery with the sediment imagery, which is acquired by correlating the atmosphere corrected AVHRR imagery with in-situ suspended sediment data. The coastal current systems affecting the sediment dispersal mainly include: the Taiwan Warm Current (TWC), the Huanghai Sea Mixed Water (HSMW), North Jiangsu near-shore current, and Zhejiang near-shore current etc. In winter, the current systems are stable. Their distribution affects the sediment from north Jiangsu expanding toward the Changjiang estuary in some degree .The front between Zhejiang coastal current and TWC blocks the expanding of sediment toward the sea. In the flood season, apart from the limitation by coastal current systems, the spatial and temporal distribution of suspended sediment is also affected by the runoff, which shows as the jet stream and fresh water. Spring and autumn are the transitional periods of the forming of expanding patterns of flood season and winter respectively. In addition, the re-suspended sediment caused by the wind wave may make the expanding range of near-shore sediment larger.展开更多
The restoration of the riparian vegetation disturbed by human activities is one of the hotspots of watershed ecology. Through interpreting the images of Remote Sensing in 1985 and 1999, the basic information of forest...The restoration of the riparian vegetation disturbed by human activities is one of the hotspots of watershed ecology. Through interpreting the images of Remote Sensing in 1985 and 1999, the basic information of forest resources of Lushuihe Forest Bureau, which is a typical forest area of Changbai Mountain, was obtained with support of GIS. By dividing Land covers of Lushuihe area into 10 types (water body, residential land, stump land, farming land, wetland, mature conifer forest, midlife conifer forest, mature broadleaf forest, midlife broadleaf forest, and man-made young forest) and dividing the riparian zone into four buffers (in turn, 1000, 2000, 3000, 4000 m away from the river), the changes of riparian forest resources during 1985-1999 were analyzed. The results showed that the deforestation intension has obviously decreased and the whole environment has been evidently improved, but the riparian ecosystem was still flimsy. In buffer 1, 2, 3, the area of midlife conifer forest increased largely, but the areas of other types of land covers all decreased. Midlife conifer forest had a comparatively good status in the three buffers. In buffer 4, midlife conifer forest, mature conifer forest, and mature broadleaf forest formed a forest-age rank that is helpful to stabilize the forest ecosystem and exert its functions. Area percentage of wetland decreased in buffer 1, buffer 2, and buffer 3, even in buffer 4 in which forest ecosystem rehabilitated comparatively well, so protecting and rehabilitating wetland is a very difficult task.展开更多
This study was conducted in Erdaobaihe River passing through the broadleaved and Korean pine forest located on the north slope of Changbai Mountain. In-stream large woody debris (LWD) in two segments of the river chan...This study was conducted in Erdaobaihe River passing through the broadleaved and Korean pine forest located on the north slope of Changbai Mountain. In-stream large woody debris (LWD) in two segments of the river channel was investigated with base diameter, top diameter, length, and decay class. To study relationship between in-stream LWD and adjacent riparian forest, species of each log of LWD in segment 1 was identified, and the riparian forest was examined by setting a 32m?4 m quadrat consisting of twelve 8m?m small quadrats. The results showed that, in segment 1, in-stream LWD loading was 1.733 m3/100m or 10.83 m3hm-2, and in segment 2, it was 1.709m3/100m or 21.36 m3hm-2. In-stream LWD in decay class III and IV were accounted for a high proportion, which was different from that in the broadleaved and Korean pine forest, and the possible reason might be different decomposing velocities due to different decomposing conditions. Logs of LWD in stream and living trees in riparian forest declined as diameter increased, and it was in a reverse J-shaped distribution except logs of LWD in segment 1 in the first diameter class. Volumes of LWD in stream and living trees in riparian forest increased as diameter increased, and it was in a typical J-shaped distribution. Loading and species component of in-stream LWD were correlative to status of riparian forest to a certain extent, and there also existed difference. Comparing the correlation and difference was helpful to study on dynamic of the riparian forest.展开更多
Characteristics of total soil seed banks and permanent soil seed banks in three microhabitats in a Mediterranean coastal sand dune were investigated by using natural germination method combined with physically scannin...Characteristics of total soil seed banks and permanent soil seed banks in three microhabitats in a Mediterranean coastal sand dune were investigated by using natural germination method combined with physically scanning separation method. The composition and structure of soil seed banks were analyzed between the microhabitats by using functional group method. The distribution patterns of soil seed bank were also analyzed between the microhabitats. We also analyzed the relationship between seed size and seed persistence in soil. The results show greatly spatial heterogeneity existed in soil seed bank of the Mediterranean coastal sand dune, even in the same microhabitats seed distribution was uneven. Sometimes a great difference occurred between them. Microhabitats significantly affected the distribution patterns of total soil seed banks and seed banks of the functional groups. The open area generally had the greater densities of seeds, but the seed densities under shrub and in trail were lower than that in the open area. Legumes seeds accounted for 76.0% total persistent seed banks. Annual and perennial grasses produced transient seed banks as no seeds were retrieved from the sieved soils. Seed persistence of legumes, umbeliferaes, perennial forbs, compositaes, annual forbs, crucifer decreased gradually. They were 50.1%, 45.6%, 40.6%, 6.3%, 5.6% and 0.6% respectively in the soil. There was a positive relationship between seed size and seed persistence. Bigger seeds had higher persistence, and vice versa.展开更多
基金This study was supported by the Chinese Academy of Sciences (A grant KZCX2-406) the National Natural Science Foundation of China (NSFC39970123) and Changbai Mountain Open Research Station.
文摘Sixteen different vegetation types of grassland and shrubland were selected to study the component and diversity of plant species of riparian plant communities along main channel in the Three-Gorges areas. Species richness (s), Simpson index (D), and Shannon-Weiner index (H) were used to study the biodiversity and the hierarchical classification was carried out by the methods of TWINSPAN and DCA ordination. The results showed that the components of flora were complex and dominated by the temperate type in the riparian plant communities. Species diversity was not different between the communities, but Shannon-Weiner indexes of different layers in some grassland were significantly different. TWINSPAN and DCA indicated that riparian plant communities distributed along the gradient of moisture.
文摘Reclamation of tidal flat is one of the main ways to get a dynamic balance of the total amount of plowland. With the development of social economy and the increasing demand for plowland, the contradiction between tidal flat reclamation and environment protection becomes more and more outstanding. However, tidal flat reclamation should also follow the dynamic balance of total amount of tidal flat amount. The paper analyzed the history of reclamation and development of Jiangsu mud coast, and calculated the feasible rates of tidal flat reclamation on different stretches respectively, and pointed out that both the economic social benefits of reclamation and the natural erosion-accretion conditions of the coasts should be taken into consideration in deciding the intensity of tidal flat reclamation, so as to satisfy demands on both reclamation and protection of tidal flat resource.
文摘Based on the combined hydraulic calculation for the eastern network region at the Pearl River estuary and several outlets to the Lingdingyang Bay, the sediment calculation modelling was introduced in the establishment of the sediment mathematical model for Lingdingyang Bay and the eastern region with one and two dimensional flow calculation. Model adjustment and verification were performed in conjunction with field data. The simulated results coincide well with measured data.In addition the model is applied to predict the shore-line planning scheme of Lingdingyang Bay.The theoretical criterion is provided for the shore line plan in the model.And a new mathematical simulated method is put out to research the planning engineering concerned with one-dimensional net rivers and two-dimensional estuary.
文摘Feiyantan was the discharge area of Diaokou River distributary of the Yellow River during the period of 1964 to 1976. The coastal erosion feature and morphological evolution at the Feiyantan coast are studied in the light of the topography and section depth, and the corresponding dynamics of wave and current. Results indicate that the protruding topography left after the Diaokou River distributary was abandoned is the main cause of strong coastal erosion. Further research suggests that waves start up the sediment and the tidal current transports it, and the waves and tidal current are combined to be the dominant dynamic mechanism of coastal erosion, in which the tidal residual current takes and transports the sediment outward, thus causing the sediment to wane in the coast.
基金This project was supported by National Natural Science Foundation of China (NSFC39970123) Changbai Mountain Open Research Station, Chinese Acedamy of Science.
文摘Due to the importance of riparian zone in maintaining and protecting regional biodiversity, increasingly more ecologists paid their attentions to riparian zone and had been aware of the important effects of riparian zone in basic study and practical management. In this study, 42 sampling belts (10 m?00 m) parallel to the bank of Xiangxi River at different elevations in Shennongjia Area were selected to investigate the riparian vegetation and rare plants. 14 species of rare plants were found distributing in riparian zone, accounting for 42.4% of the total rare plant species in Shennongjia Area. The main distribution range of the 14 rare plant species was the evergreen and deciduous mixed broadleaved forest at elevation of 1200-1800 m, where, species diversity of plant community was the maximum at the moderate elevation. The analysis of TWINSPAN divided the 14 rare species into 3 groups against the elevation, namely low elevation species group, moderate elevation species group, and high elevation species group. The analysis of DCA ordination showed similar results to that of TWINSPAN. In the paper, the authors discussed the reasons forming the distribution pattern of rare plant species, and pointed out that the important function of riparian zone on rare plant species protection.
文摘This paper, with NOAA/AHHRR data for 2 years, discusses the expanding path and extent of suspended sediment from the Changjiang River, and the relationship between the suspended sediment expanding and coastal current systems by analyzing the thermal infrared imagery with the sediment imagery, which is acquired by correlating the atmosphere corrected AVHRR imagery with in-situ suspended sediment data. The coastal current systems affecting the sediment dispersal mainly include: the Taiwan Warm Current (TWC), the Huanghai Sea Mixed Water (HSMW), North Jiangsu near-shore current, and Zhejiang near-shore current etc. In winter, the current systems are stable. Their distribution affects the sediment from north Jiangsu expanding toward the Changjiang estuary in some degree .The front between Zhejiang coastal current and TWC blocks the expanding of sediment toward the sea. In the flood season, apart from the limitation by coastal current systems, the spatial and temporal distribution of suspended sediment is also affected by the runoff, which shows as the jet stream and fresh water. Spring and autumn are the transitional periods of the forming of expanding patterns of flood season and winter respectively. In addition, the re-suspended sediment caused by the wind wave may make the expanding range of near-shore sediment larger.
基金This study is supported by major projects of Knowledge Innovation Program Chinese Academy of Sciences ( No. KZCX2-SW-320-3) and Institute of Applied Ecology (a grant SCXZD010-01)CAS
文摘The restoration of the riparian vegetation disturbed by human activities is one of the hotspots of watershed ecology. Through interpreting the images of Remote Sensing in 1985 and 1999, the basic information of forest resources of Lushuihe Forest Bureau, which is a typical forest area of Changbai Mountain, was obtained with support of GIS. By dividing Land covers of Lushuihe area into 10 types (water body, residential land, stump land, farming land, wetland, mature conifer forest, midlife conifer forest, mature broadleaf forest, midlife broadleaf forest, and man-made young forest) and dividing the riparian zone into four buffers (in turn, 1000, 2000, 3000, 4000 m away from the river), the changes of riparian forest resources during 1985-1999 were analyzed. The results showed that the deforestation intension has obviously decreased and the whole environment has been evidently improved, but the riparian ecosystem was still flimsy. In buffer 1, 2, 3, the area of midlife conifer forest increased largely, but the areas of other types of land covers all decreased. Midlife conifer forest had a comparatively good status in the three buffers. In buffer 4, midlife conifer forest, mature conifer forest, and mature broadleaf forest formed a forest-age rank that is helpful to stabilize the forest ecosystem and exert its functions. Area percentage of wetland decreased in buffer 1, buffer 2, and buffer 3, even in buffer 4 in which forest ecosystem rehabilitated comparatively well, so protecting and rehabilitating wetland is a very difficult task.
基金This paper was supported by the Chinese Academy of Sciences (KZCX2-406) and National Natural Science Foundation of China (NSFC39970123) and Changbai Mountain Open Research Station.
文摘This study was conducted in Erdaobaihe River passing through the broadleaved and Korean pine forest located on the north slope of Changbai Mountain. In-stream large woody debris (LWD) in two segments of the river channel was investigated with base diameter, top diameter, length, and decay class. To study relationship between in-stream LWD and adjacent riparian forest, species of each log of LWD in segment 1 was identified, and the riparian forest was examined by setting a 32m?4 m quadrat consisting of twelve 8m?m small quadrats. The results showed that, in segment 1, in-stream LWD loading was 1.733 m3/100m or 10.83 m3hm-2, and in segment 2, it was 1.709m3/100m or 21.36 m3hm-2. In-stream LWD in decay class III and IV were accounted for a high proportion, which was different from that in the broadleaved and Korean pine forest, and the possible reason might be different decomposing velocities due to different decomposing conditions. Logs of LWD in stream and living trees in riparian forest declined as diameter increased, and it was in a reverse J-shaped distribution except logs of LWD in segment 1 in the first diameter class. Volumes of LWD in stream and living trees in riparian forest increased as diameter increased, and it was in a typical J-shaped distribution. Loading and species component of in-stream LWD were correlative to status of riparian forest to a certain extent, and there also existed difference. Comparing the correlation and difference was helpful to study on dynamic of the riparian forest.
文摘Characteristics of total soil seed banks and permanent soil seed banks in three microhabitats in a Mediterranean coastal sand dune were investigated by using natural germination method combined with physically scanning separation method. The composition and structure of soil seed banks were analyzed between the microhabitats by using functional group method. The distribution patterns of soil seed bank were also analyzed between the microhabitats. We also analyzed the relationship between seed size and seed persistence in soil. The results show greatly spatial heterogeneity existed in soil seed bank of the Mediterranean coastal sand dune, even in the same microhabitats seed distribution was uneven. Sometimes a great difference occurred between them. Microhabitats significantly affected the distribution patterns of total soil seed banks and seed banks of the functional groups. The open area generally had the greater densities of seeds, but the seed densities under shrub and in trail were lower than that in the open area. Legumes seeds accounted for 76.0% total persistent seed banks. Annual and perennial grasses produced transient seed banks as no seeds were retrieved from the sieved soils. Seed persistence of legumes, umbeliferaes, perennial forbs, compositaes, annual forbs, crucifer decreased gradually. They were 50.1%, 45.6%, 40.6%, 6.3%, 5.6% and 0.6% respectively in the soil. There was a positive relationship between seed size and seed persistence. Bigger seeds had higher persistence, and vice versa.