Trees on sand dunes are more sensitive to environmental changes because sandy soils have extremely low water holding capacity and nutrient availability. We investigated the dynamics of soil respiration(Rs) for seconda...Trees on sand dunes are more sensitive to environmental changes because sandy soils have extremely low water holding capacity and nutrient availability. We investigated the dynamics of soil respiration(Rs) for secondary natural Litsea forest and plantations of casuarina,pine, acacia and eucalyptus. Results show that significant diurnal variations of Rsoccurred in autumn for the eucalyptus species and in summer for the pine species, with higher mean soil respiration at night. However, significant seasonal variations of Rswere found in all five forest stands. Rschanged exponentially with soil temperatures at the 10-cm depth; the models explain 43.3–77.0% of Rs variations. Positive relationships between seasonal Rsand soil moisture varied with stands. The correlations were significant only in the secondary forest, and the eucalyptus and pine plantations. The temperature sensitivity parameter(Q10 value) of Rsranged from 1.64 in casuarina plantation to 2.32 the in secondary forest; annual Rswas highest in the secondary forest and lowest in the pine plantation. The results indicate that soil temperatures and moisture are the primary environmental controls of soil respiration and mainly act through a direct influence on roots and microbial activity. Differences in root biomass, quality of litter,and soil properties(pH, total N, available P, and exchangeable Mg) were also significant factors.展开更多
Information on habitat use is critical in sizing protected areas for endangered reptile species. To investigate habitat use, home range, and hibernaculum of the endangered Mongolian Racerunner(Eremias argus), we radio...Information on habitat use is critical in sizing protected areas for endangered reptile species. To investigate habitat use, home range, and hibernaculum of the endangered Mongolian Racerunner(Eremias argus), we radio-tracked 40 specimens in a coastal sand dune in South Korea. Of the 163 locations recorded during the breeding season, 150(92.0%) were in grass sand dunes, and the rest(8.0%), all associated with the same lizard, were in shrub sand dunes. All of the 123 locations recorded during the non-breeding season were in grass sand dunes. No lizards were found in the grasslands abutting the dunes. The four lizards with identifiable hibernation sites were found under an average of 17.8 cm of sand and were all located in grass sand dunes. The lizards moved approximately 5 m daily and used 162 m2of home range(computed by minimum convex polygon, MCP) during the breeding season, and they moved approximately 2 m and used 68 m2of home range during the non-breeding season. However, the mean daily moved distances and MCP home ranges were not statistically significantly different between the seasons or between males and females. Our results suggest that in coastal sand dunes, E. argus uses grass sand dunes as its main habitat throughout the year. This finding could be used to determine the appropriate habitat size and to designate for the conservation of this endangered species.展开更多
Evaluation of 450 surface sterilized tissue segments of a seasonal wild legume, Sesbania bispinosa （Jacq.）, of coastal sand dunes and mangroves of southwest India yielded 546 isolates comprising 39 endophytic fungi ...Evaluation of 450 surface sterilized tissue segments of a seasonal wild legume, Sesbania bispinosa （Jacq.）, of coastal sand dunes and mangroves of southwest India yielded 546 isolates comprising 39 endophytic fungi with six dominant taxa （Aspergillus flavus, Aspergillus niger, Cladosporium tenuissimum, Fusarium moniliforme, Penicillium chrysogenum and morpho sp. 1）. A consortium of saprophytic, pathogenic and toxigenic fungi exists as endophytes in S. bispinosa. Number of segments colonized, number of isolates obtained, species richness and diversity were higher in S. bispinosa in mangroves compared to coastal sand dunes. Seeds yielded more fungal isolates, but species richness and diversity were low. In spite of low fungal colonization in root segments, the diversity was high. Up to 30-40 % endophytic fungi of S. bispinosa differed between coastal sand dunes and mangroves revealing partial host- and habitat-specificity. As S. bispi- nosa is extensively used as green manure and forage in southwest India, further studies especially on the bioactive compounds of its endophytic fungi might broaden its range of uses. In addition to conventional morphologicaltechniques, molecular tools would provide precise insight on the endophytic fungi of coastal sand dunes and mangroves.展开更多
Coastal dunes are among the most complex interfaces to study in the world. Improving the knowledge of their morphodynamics is essential to better understand the present evolutions and try to anticipate future. The rec...Coastal dunes are among the most complex interfaces to study in the world. Improving the knowledge of their morphodynamics is essential to better understand the present evolutions and try to anticipate future. The recent use of the new vectors that are drones, UAV and UAS, improves the temporal and spatial resolutions of geomatic data acquired on these environments. Many studies attempt to measure the sedimentary variations that occur from one date to another by the use of differential volumes. In particular, they make it possible to understand the roles of storms, sometimes erosive, as well as the possible morphological responses of associated reconstruction periods. One of the primary methods for calculating volume evolutions is the assessment of a vertical delimitation of the dune toe. However, it is difficult to limit mobile and variable environment, temporally and spatially, to a simple vertical topographic delimitation. This study was realized to estimate the error induced by the use of the vertical threshold method. In the examples that were done, this error was far from being negligible and might in some cases exceed the evolutions of measured volumes. In overcoming this problem, an alternative method was developed. It was the seemingly better adaptability to these mobile environments that are the coastal dunes.展开更多
Coastal dunes are a common geomorphic type in sandy coastal zones.They are a record of the coupled evolutionary processes of the wind and ocean waves.Many coastal dune fields have developed on the east coast of Fujian...Coastal dunes are a common geomorphic type in sandy coastal zones.They are a record of the coupled evolutionary processes of the wind and ocean waves.Many coastal dune fields have developed on the east coast of Fujian China and now occur as widespread typical coastal aeolian sand landforms on the Liuao Peninsula,Gulei Peninsula and Dongshan Island,but it is difficult to evaluate the dynamic geomorphologic process of sandy coast due to the lack of systematic and accurate chronological data.In this study,we selected the Hutoushan(HTS)aeolian dune on the Liuao Peninsula as the research object.Optical dating and grain-size analysis were applied to sand samples from the aeolian sequence of a profile of the HTS dune.The results show that the ages of seven samples of this profile were in the range of 37.8–0.19 ka from 4.0 to 0.2 m deep.These correspond to the Marine Isotope Stage 3(MIS3),abrupt climatic change events of 4.2 and 1.1 ka and the Little Ice Age(LIA),respectively.These samples displayed evidence of a longer-term climate trend in this area.The period of formation of this coastal aeolian dune corresponds to a cold and arid climate associated with the East Asia Winter Monsoon(EAWM).Periods of dune fixation and rubification are evidence of a hot and humid climate.Mobilization and stabilization of the aeolian dune is an important characteristic of the coastal evolution in South China since the late Pleistocene.展开更多
Rhynchostegium megapolitanum was observed during a study of the effects of the invasive nonnative Rosa rugosa in a sand dune. The vascular as well as the epiphytic and epigeic cryptogam vegetation was recorded., and s...Rhynchostegium megapolitanum was observed during a study of the effects of the invasive nonnative Rosa rugosa in a sand dune. The vascular as well as the epiphytic and epigeic cryptogam vegetation was recorded., and soil properties were measured. Epihytic lichens were abundant on dead or dying branches of Rosa rugosa scrubs, under which the stable substrate and high light exposure provided growth conditions for an epigeic community dominated by lichens and bryophytes. The occurrence of the rare bryophyte Rhynchostegium megapolitanum is discussed.展开更多
Ⅰ. INTRODUCTIONDune activity across northern Australia is currently the focus of a joint research project between the Australian National University and the Xi’an Laboratory of Loess and Quaternary Geology, Academia...Ⅰ. INTRODUCTIONDune activity across northern Australia is currently the focus of a joint research project between the Australian National University and the Xi’an Laboratory of Loess and Quaternary Geology, Academia Sinica. Although the project is not yet completed, there is sufficient data available to allow discussion of the general setting of the dune fields studied to date. These include the dune fields near Shelbume Bay and Cape Flattery, eastern Cape York, Cobourg Peninsula, Arnhemland, and Groote Eylandt, Gulf of Carpentaria(Fig. 1).展开更多
基金supported by the National Natural Science Foundation of China(31570604,41371269)The Basal Research Fund of Fujian provincial Public Scientific Research Institution support(2014R1011-7)the Casuarina Research Center of Engineering and Technology,and the Key Laboratory of Forest Culture and Forest Product Processing Utilization of Fujian Province
文摘Trees on sand dunes are more sensitive to environmental changes because sandy soils have extremely low water holding capacity and nutrient availability. We investigated the dynamics of soil respiration(Rs) for secondary natural Litsea forest and plantations of casuarina,pine, acacia and eucalyptus. Results show that significant diurnal variations of Rsoccurred in autumn for the eucalyptus species and in summer for the pine species, with higher mean soil respiration at night. However, significant seasonal variations of Rswere found in all five forest stands. Rschanged exponentially with soil temperatures at the 10-cm depth; the models explain 43.3–77.0% of Rs variations. Positive relationships between seasonal Rsand soil moisture varied with stands. The correlations were significant only in the secondary forest, and the eucalyptus and pine plantations. The temperature sensitivity parameter(Q10 value) of Rsranged from 1.64 in casuarina plantation to 2.32 the in secondary forest; annual Rswas highest in the secondary forest and lowest in the pine plantation. The results indicate that soil temperatures and moisture are the primary environmental controls of soil respiration and mainly act through a direct influence on roots and microbial activity. Differences in root biomass, quality of litter,and soil properties(pH, total N, available P, and exchangeable Mg) were also significant factors.
基金supported by the Korean Ministry of Environment as "The Eco-Technopia 21 Project (#052-091-080)"
文摘Information on habitat use is critical in sizing protected areas for endangered reptile species. To investigate habitat use, home range, and hibernaculum of the endangered Mongolian Racerunner(Eremias argus), we radio-tracked 40 specimens in a coastal sand dune in South Korea. Of the 163 locations recorded during the breeding season, 150(92.0%) were in grass sand dunes, and the rest(8.0%), all associated with the same lizard, were in shrub sand dunes. All of the 123 locations recorded during the non-breeding season were in grass sand dunes. No lizards were found in the grasslands abutting the dunes. The four lizards with identifiable hibernation sites were found under an average of 17.8 cm of sand and were all located in grass sand dunes. The lizards moved approximately 5 m daily and used 162 m2of home range(computed by minimum convex polygon, MCP) during the breeding season, and they moved approximately 2 m and used 68 m2of home range during the non-breeding season. However, the mean daily moved distances and MCP home ranges were not statistically significantly different between the seasons or between males and females. Our results suggest that in coastal sand dunes, E. argus uses grass sand dunes as its main habitat throughout the year. This finding could be used to determine the appropriate habitat size and to designate for the conservation of this endangered species.
文摘Evaluation of 450 surface sterilized tissue segments of a seasonal wild legume, Sesbania bispinosa （Jacq.）, of coastal sand dunes and mangroves of southwest India yielded 546 isolates comprising 39 endophytic fungi with six dominant taxa （Aspergillus flavus, Aspergillus niger, Cladosporium tenuissimum, Fusarium moniliforme, Penicillium chrysogenum and morpho sp. 1）. A consortium of saprophytic, pathogenic and toxigenic fungi exists as endophytes in S. bispinosa. Number of segments colonized, number of isolates obtained, species richness and diversity were higher in S. bispinosa in mangroves compared to coastal sand dunes. Seeds yielded more fungal isolates, but species richness and diversity were low. In spite of low fungal colonization in root segments, the diversity was high. Up to 30-40 % endophytic fungi of S. bispinosa differed between coastal sand dunes and mangroves revealing partial host- and habitat-specificity. As S. bispi- nosa is extensively used as green manure and forage in southwest India, further studies especially on the bioactive compounds of its endophytic fungi might broaden its range of uses. In addition to conventional morphologicaltechniques, molecular tools would provide precise insight on the endophytic fungi of coastal sand dunes and mangroves.
文摘Coastal dunes are among the most complex interfaces to study in the world. Improving the knowledge of their morphodynamics is essential to better understand the present evolutions and try to anticipate future. The recent use of the new vectors that are drones, UAV and UAS, improves the temporal and spatial resolutions of geomatic data acquired on these environments. Many studies attempt to measure the sedimentary variations that occur from one date to another by the use of differential volumes. In particular, they make it possible to understand the roles of storms, sometimes erosive, as well as the possible morphological responses of associated reconstruction periods. One of the primary methods for calculating volume evolutions is the assessment of a vertical delimitation of the dune toe. However, it is difficult to limit mobile and variable environment, temporally and spatially, to a simple vertical topographic delimitation. This study was realized to estimate the error induced by the use of the vertical threshold method. In the examples that were done, this error was far from being negligible and might in some cases exceed the evolutions of measured volumes. In overcoming this problem, an alternative method was developed. It was the seemingly better adaptability to these mobile environments that are the coastal dunes.
基金supported by National Natural Science Foundation of China (Grant Nos. 41301012, 41771020)Special Research of Public Welfare Scientific Research Institutes of Fujian Province, China (Grant No. 2018R1034-5)the Innovation Research Team Fund of Fujian Normal University (Grant No. IRTL1705)
文摘Coastal dunes are a common geomorphic type in sandy coastal zones.They are a record of the coupled evolutionary processes of the wind and ocean waves.Many coastal dune fields have developed on the east coast of Fujian China and now occur as widespread typical coastal aeolian sand landforms on the Liuao Peninsula,Gulei Peninsula and Dongshan Island,but it is difficult to evaluate the dynamic geomorphologic process of sandy coast due to the lack of systematic and accurate chronological data.In this study,we selected the Hutoushan(HTS)aeolian dune on the Liuao Peninsula as the research object.Optical dating and grain-size analysis were applied to sand samples from the aeolian sequence of a profile of the HTS dune.The results show that the ages of seven samples of this profile were in the range of 37.8–0.19 ka from 4.0 to 0.2 m deep.These correspond to the Marine Isotope Stage 3(MIS3),abrupt climatic change events of 4.2 and 1.1 ka and the Little Ice Age(LIA),respectively.These samples displayed evidence of a longer-term climate trend in this area.The period of formation of this coastal aeolian dune corresponds to a cold and arid climate associated with the East Asia Winter Monsoon(EAWM).Periods of dune fixation and rubification are evidence of a hot and humid climate.Mobilization and stabilization of the aeolian dune is an important characteristic of the coastal evolution in South China since the late Pleistocene.
文摘Rhynchostegium megapolitanum was observed during a study of the effects of the invasive nonnative Rosa rugosa in a sand dune. The vascular as well as the epiphytic and epigeic cryptogam vegetation was recorded., and soil properties were measured. Epihytic lichens were abundant on dead or dying branches of Rosa rugosa scrubs, under which the stable substrate and high light exposure provided growth conditions for an epigeic community dominated by lichens and bryophytes. The occurrence of the rare bryophyte Rhynchostegium megapolitanum is discussed.
文摘Ⅰ. INTRODUCTIONDune activity across northern Australia is currently the focus of a joint research project between the Australian National University and the Xi’an Laboratory of Loess and Quaternary Geology, Academia Sinica. Although the project is not yet completed, there is sufficient data available to allow discussion of the general setting of the dune fields studied to date. These include the dune fields near Shelbume Bay and Cape Flattery, eastern Cape York, Cobourg Peninsula, Arnhemland, and Groote Eylandt, Gulf of Carpentaria(Fig. 1).
