The community characteristics of mangroves in the Futian Nature Reserve, Shenzhen, China are given based on surveying of 33 quadrats in 4 transects which stretch from the higher tidal zone to the lower tidal zone. The...The community characteristics of mangroves in the Futian Nature Reserve, Shenzhen, China are given based on surveying of 33 quadrats in 4 transects which stretch from the higher tidal zone to the lower tidal zone. The results show that there are 6 community types in this area: Kandelia candel association, Avicennia marina association, Aegiceras corniculatum association, Kandelia candel + Aegiceras corniculatum association, Aegiceras corniculatum + Kandelia candel association and Acanthus ilicifolius association. Kandelia candel, Aegiceras corniculatum and Avicennia marina dominate the typical quadrats. Kandelia candel can be seen at almost all quadrats, Aegiceras corniculatum distributes mostly toward the estuary and the higher tidal zone, Avicennia marina distributes mostly toward the bay and the lower tidal zone, Bruguiera gymnorrhiza occasionally occurs toward the Estuary with one or several individuals, Acanthus ilicifolius was common toward the higher tidal zone, as an accompanying species, Derris trifoliata was common in many mature quadrats. Totally, 6 species of mangrove plants and 3 species of semi-mangrove plants appear in this research area. From the higher tidal zone to the lower tidal zone, the average diameter and basal area of mangrove trees increase gradually. According to the results, the Avicennia marina dominates in average diameter and basal area, and the Aegiceras corniculatum trees are on the contrary. From the transect 1 to the transect 4, the importance value of Avicennia marina, Bruguiera gymnorrhiza and Kandelia candel decreases, and Aegiceras corniculatum increases. In this area, the Kandelia candel population and Aegiceras corniculatum population are developing populations with many seedlings and saplings, but the Avicennia marina population is in a mature stage with few seedlings and not so many total individuals. According to this research, we suppose that Aegiceras corniculatum should be developed toward the estuary and the Avicennia marina association should be protected.展开更多
Guizhou Province is an important karst area in the world and a fragile ecological area in China. Ecological risk assessment is very necessary to be conducted in this region. This study investigates different character...Guizhou Province is an important karst area in the world and a fragile ecological area in China. Ecological risk assessment is very necessary to be conducted in this region. This study investigates different characteristics of the spatial-temporal changes of vegetation cover in Guizhou Province of Southern China using the data set of SPOT VEGETATION(1999–2015) at spatial resolution of 1-km and temporal resolution of 10-day. The coefficient of variation, the Theil-Sen median trend analysis, and the Mann-Kendall test are used to investigate the spatial-temporal change of vegetation cover and its future trend. Results show that: 1) the spatial distribution pattern of vegetation cover in Guizhou Plateau is high in the east whereas low in the west. The average annual normalized difference vegetation index(NDVI) from west to east is higher than that from south to north. 2) Average annual NDVI improved obviously in the past 17 years. The growth rate of average annual NDVI is 0.028/10 yr, which is slower than that of vegetation in the country(0.048/10 yr) from 1998 to 2007. Average annual NDVI in karst area is lower than that in non-karst area. However, the growing rate of average annual NDVI in karst area(0.030/10 yr) is faster than that in non-karst area(0.023/10 yr), indicating that vegetation coverage increases more rapidly in karst area. 3) Vegetation coverage in the study area is stable overall, but fluctuates in the local scales. 4) Vegetation coverage presents a continuous increasing trend. The Hurst exponent of NDVI in different vegetation types has an obvious threshold in various elevations. 5) The proportion of vegetation cover with sustainable increase is higher than that of vegetation cover with sustainable decrease. The improvement in vegetation cover may expand to most parts of the study area.展开更多
This research,by use of RS image_simulating method,simulated apparent reflectance images at sensor level and ground_reflectance images of SPOT_HRV,CBERS_CCD,Landsat_TM and NOAA14_AVHRR’s corresponding bands.These ima...This research,by use of RS image_simulating method,simulated apparent reflectance images at sensor level and ground_reflectance images of SPOT_HRV,CBERS_CCD,Landsat_TM and NOAA14_AVHRR’s corresponding bands.These images were used to analyze sensor’s differences caused by spectral sensitivity and atmospheric impacts.The differences were analyzed on Normalized Difference Vegetation Index(NDVI).The results showed that the differences of sensors’ spectral characteristics cause changes of their NDVI and reflectance.When multiple sensors’ data are applied to digital analysis,the error should be taken into account.Atmospheric effect makes NDVI smaller,and atmospheric correction has the tendency of increasing NDVI values.The reflectance and their NDVIs of different sensors can be used to analyze the differences among sensor’s features.The spectral analysis method based on RS simulated images can provide a new way to design the spectral characteristics of new sensors.展开更多
We have examined the carotenoid contents of several dark green vegetables found to be associated with a lower risk of various epithelial cancers in our epidemiological study and animal study. Samples of these vegetabl...We have examined the carotenoid contents of several dark green vegetables found to be associated with a lower risk of various epithelial cancers in our epidemiological study and animal study. Samples of these vegetables were quantitatively examined by highperformance liquid chromatography (HPLC) on a C-18 reversed-phase column for individual carotenoid content. Pure reference compounds (alpha-carotene, beta-carotent, lycopene, canthaxanthin, and lutein) and internal standard (beta-Apo-8'-carotenal) were employed to quantify xanthophylls and carotenes in these vegetables. The results indicated that fresh, dark-green, leafy vegetables were high in beta-carotene (0.94-9.36 mg/100 g) and oxygenated carotenoids or xanthophylls, primarily lutein (0.94-7.39 mg/100 g),whereas lycopene and alpha-carotene were not prominent and canthaxanthin was non existent in these vegetables. These analyses suggest that consumption of carotenoids such as lutein in addition to beta-carotene may be associated with a lower risk of cancers展开更多
We studied variations in tree biomass and carbon sequestration rates of Chir Pine （Pinus roxburghii. Sarg.） forest in three categories of forest disturbance, protected, moderately disturbed, and highly disturbed. In...We studied variations in tree biomass and carbon sequestration rates of Chir Pine （Pinus roxburghii. Sarg.） forest in three categories of forest disturbance, protected, moderately disturbed, and highly disturbed. In the first year, total biomass was 14.7.t.ha-1 in highly disturbed site, 94.46 t.ha-1 in moderately disturbed forest, and 112.0 t.ha-1 in protected forest. The soil organic carbon in the top 20 cm of soil ranged from 0.63 to 1.2%. The total rate of carbon sequestration was 0.60 （t/ha）.a-lon the highly disturbed site, 1.03 （t/ha）a-1 on the moderately disturbed site, and 4.3 （t/ha）.a-1 on the protectedsite. Keywords： carbon sequestration, soil organic carbon （SOC）, disturbed forest, vegetation analysis, allometric equations展开更多
Forest and vegetation of particular ecosystem is generally influenced by external factors especially from development activities. Nepal has been endowed with an immense variety of forest resources with its unique biod...Forest and vegetation of particular ecosystem is generally influenced by external factors especially from development activities. Nepal has been endowed with an immense variety of forest resources with its unique biodiversity. The current study is conducted in the temperate forest of central Nepal to compare the state of vegetation recorded during 1995 with the present condition. To identify floristic composition, species distribution and diversity, same location and same size of quadrates were selected in natural forest and planted or regenerated area as in previous study. Measurement and analytical tools for forest and vegetation reveled a total of 19 species and 341 individuals in 0.14 ha regenerated area and 18 species, 17 genera and 260 individuals in 0.16 ha, natural forest areas. However, in 1995, total 31 individuals of 20 woody species, 18 genera and 15 families were recorded within the sampling plots of 0.16 ha of natural forest. Moreover, Alnus nepalensis is found dominating regenerated area and Caryopteris odorata in natural forests whereas in 1995, Litsea chartacea and Maesa chisia were recorded dominant. The Shannon’s diversity H’ = 2.908, E = 0.970 and Var H’ = -0.00 and Simpsons D = 0.027 recorded in 1995 is found to be with higher values when compared with the analysis of present study. Furthermore, in comparison to 1995 study, this study showed lower basal area and timber volume with declining species diversity. Although, the natural forest is found with higher species composition compared to rehabilitated forest, species of herbs and shrubs were found extensively growing.展开更多
To better ascertain leaf, stem and flower traits, and analyze aboveground allocation during the vegetation period, three sampling vegetation transects were settled and reed samples were collected at intervals to deter...To better ascertain leaf, stem and flower traits, and analyze aboveground allocation during the vegetation period, three sampling vegetation transects were settled and reed samples were collected at intervals to determine morphological parameters and dry and wet weights in Jiaozhou Bay wetland. Remote sensing data were also combined to evaluate regional biomass through EVI regression models. Results show that growth dynamics of leaves and stems changed during the vegetation period. Stem length increased rapidly and peaked in September（194.40 ± 23.89 cm）, whereas leaf width peaked in July. There was a significantly negative correlation between stem length and stem diameter with a value of-0.785. Stem biomass was higher than that of leaves, and the maximum value of aboveground biomass was 27.17 ± 3.56 g. F/C exhibited a tendency to increase and values ranged from 0.37–0.76. The aboveground biomass of sample plots reached a peak of 2356 ± 457 g/m^2 in September. EVI was 0.05–0.5; EVI and biomass had a better fitting effect using the power-exponent model compared with other models and its function was y = 4219.30 x^0.88（R^2 = 0.7810）. R^2 of the other three models ranked as linear function〉 polynomial function 〉exponent function, with the values being 0.7769, 0.7623 and 0.6963, respectively. EVI can be used to estimate vegetation biomass, and effectively solved the problems of the destructive effect to sample plots resulting from traditional harvest methods.展开更多
Plant growth contributes to mineral weathering, but this contribution remains poorly understood. Weathering rates in an aggrading forested watershed in subtropical China were studied by means of geochemical mass balan...Plant growth contributes to mineral weathering, but this contribution remains poorly understood. Weathering rates in an aggrading forested watershed in subtropical China were studied by means of geochemical mass balance. Rainfall, dry deposition, and streamwater were monitored from March 2007 to February 2012. Samples of vegetative components, rainfall, dry deposition, streamwater, representative soils, and parent rock were collected and determined for mass balance calculation and clarifying plant-driven weathering mechanisms stoichiometrically. Ignoring biomass, weathering rates of Ca^2＋, Mg^2＋, Na^＋, and Si were 25.6, 10.7, 2.8, and 51.0 kg ha^-1 year^-1, respectively. Taking biomass into consideration, weathering rates of Ca^2＋, Mg^2＋, and Si and the sum of weathering rates of Ca^2＋, Mg^2＋, Na^＋, K^＋, and Si were 2.6, 1.8, 1.2, and 1.5-fold higher than those ignoring biomass, respectively. This is attributed to plant-driven weathering due to the nutrient （e.g., Ca^2＋, Mg^2＋, and K^＋） absorption by vegetation and substantial proton production during assimilation of these nutrients, with the former acting as a pump for removing weathering products and the latter being a source of weathering agents solubilizing mineral components. The same pattern of weathering, i.e., higher rates of weathering with than without including biomass in mass balance calculation, was reported in previous studies; however, the extent to which plants drive weathering rates varied with vegetation types and climatic zones. The documented biological weathering driven by plants is expected to play a critical role in regulating nutrient cycling and material flows within the Earth＇s Critical Zone.展开更多
文摘The community characteristics of mangroves in the Futian Nature Reserve, Shenzhen, China are given based on surveying of 33 quadrats in 4 transects which stretch from the higher tidal zone to the lower tidal zone. The results show that there are 6 community types in this area: Kandelia candel association, Avicennia marina association, Aegiceras corniculatum association, Kandelia candel + Aegiceras corniculatum association, Aegiceras corniculatum + Kandelia candel association and Acanthus ilicifolius association. Kandelia candel, Aegiceras corniculatum and Avicennia marina dominate the typical quadrats. Kandelia candel can be seen at almost all quadrats, Aegiceras corniculatum distributes mostly toward the estuary and the higher tidal zone, Avicennia marina distributes mostly toward the bay and the lower tidal zone, Bruguiera gymnorrhiza occasionally occurs toward the Estuary with one or several individuals, Acanthus ilicifolius was common toward the higher tidal zone, as an accompanying species, Derris trifoliata was common in many mature quadrats. Totally, 6 species of mangrove plants and 3 species of semi-mangrove plants appear in this research area. From the higher tidal zone to the lower tidal zone, the average diameter and basal area of mangrove trees increase gradually. According to the results, the Avicennia marina dominates in average diameter and basal area, and the Aegiceras corniculatum trees are on the contrary. From the transect 1 to the transect 4, the importance value of Avicennia marina, Bruguiera gymnorrhiza and Kandelia candel decreases, and Aegiceras corniculatum increases. In this area, the Kandelia candel population and Aegiceras corniculatum population are developing populations with many seedlings and saplings, but the Avicennia marina population is in a mature stage with few seedlings and not so many total individuals. According to this research, we suppose that Aegiceras corniculatum should be developed toward the estuary and the Avicennia marina association should be protected.
基金Under the auspices of National Key Research Program of China(No.2016YFC0502300,2016YFC0502102,2014BAB03B00)National Key Research and Development Program(No.2014BAB03B02)+3 种基金Agricultural Science and Technology Key Project of Guizhou Province of China(No.2014-3039)Science and Technology Plan Projects of Guiyang Municipal Bureau of Science and Technology of China(No.2012-205)Science and Technology Plan of Guizhou Province of China(No.2012-6015)Guangxi Natural Science Foundation of China(No.2014GXNSFBA118221)
文摘Guizhou Province is an important karst area in the world and a fragile ecological area in China. Ecological risk assessment is very necessary to be conducted in this region. This study investigates different characteristics of the spatial-temporal changes of vegetation cover in Guizhou Province of Southern China using the data set of SPOT VEGETATION(1999–2015) at spatial resolution of 1-km and temporal resolution of 10-day. The coefficient of variation, the Theil-Sen median trend analysis, and the Mann-Kendall test are used to investigate the spatial-temporal change of vegetation cover and its future trend. Results show that: 1) the spatial distribution pattern of vegetation cover in Guizhou Plateau is high in the east whereas low in the west. The average annual normalized difference vegetation index(NDVI) from west to east is higher than that from south to north. 2) Average annual NDVI improved obviously in the past 17 years. The growth rate of average annual NDVI is 0.028/10 yr, which is slower than that of vegetation in the country(0.048/10 yr) from 1998 to 2007. Average annual NDVI in karst area is lower than that in non-karst area. However, the growing rate of average annual NDVI in karst area(0.030/10 yr) is faster than that in non-karst area(0.023/10 yr), indicating that vegetation coverage increases more rapidly in karst area. 3) Vegetation coverage in the study area is stable overall, but fluctuates in the local scales. 4) Vegetation coverage presents a continuous increasing trend. The Hurst exponent of NDVI in different vegetation types has an obvious threshold in various elevations. 5) The proportion of vegetation cover with sustainable increase is higher than that of vegetation cover with sustainable decrease. The improvement in vegetation cover may expand to most parts of the study area.
文摘This research,by use of RS image_simulating method,simulated apparent reflectance images at sensor level and ground_reflectance images of SPOT_HRV,CBERS_CCD,Landsat_TM and NOAA14_AVHRR’s corresponding bands.These images were used to analyze sensor’s differences caused by spectral sensitivity and atmospheric impacts.The differences were analyzed on Normalized Difference Vegetation Index(NDVI).The results showed that the differences of sensors’ spectral characteristics cause changes of their NDVI and reflectance.When multiple sensors’ data are applied to digital analysis,the error should be taken into account.Atmospheric effect makes NDVI smaller,and atmospheric correction has the tendency of increasing NDVI values.The reflectance and their NDVIs of different sensors can be used to analyze the differences among sensor’s features.The spectral analysis method based on RS simulated images can provide a new way to design the spectral characteristics of new sensors.
文摘We have examined the carotenoid contents of several dark green vegetables found to be associated with a lower risk of various epithelial cancers in our epidemiological study and animal study. Samples of these vegetables were quantitatively examined by highperformance liquid chromatography (HPLC) on a C-18 reversed-phase column for individual carotenoid content. Pure reference compounds (alpha-carotene, beta-carotent, lycopene, canthaxanthin, and lutein) and internal standard (beta-Apo-8'-carotenal) were employed to quantify xanthophylls and carotenes in these vegetables. The results indicated that fresh, dark-green, leafy vegetables were high in beta-carotene (0.94-9.36 mg/100 g) and oxygenated carotenoids or xanthophylls, primarily lutein (0.94-7.39 mg/100 g),whereas lycopene and alpha-carotene were not prominent and canthaxanthin was non existent in these vegetables. These analyses suggest that consumption of carotenoids such as lutein in addition to beta-carotene may be associated with a lower risk of cancers
文摘We studied variations in tree biomass and carbon sequestration rates of Chir Pine （Pinus roxburghii. Sarg.） forest in three categories of forest disturbance, protected, moderately disturbed, and highly disturbed. In the first year, total biomass was 14.7.t.ha-1 in highly disturbed site, 94.46 t.ha-1 in moderately disturbed forest, and 112.0 t.ha-1 in protected forest. The soil organic carbon in the top 20 cm of soil ranged from 0.63 to 1.2%. The total rate of carbon sequestration was 0.60 （t/ha）.a-lon the highly disturbed site, 1.03 （t/ha）a-1 on the moderately disturbed site, and 4.3 （t/ha）.a-1 on the protectedsite. Keywords： carbon sequestration, soil organic carbon （SOC）, disturbed forest, vegetation analysis, allometric equations
文摘Forest and vegetation of particular ecosystem is generally influenced by external factors especially from development activities. Nepal has been endowed with an immense variety of forest resources with its unique biodiversity. The current study is conducted in the temperate forest of central Nepal to compare the state of vegetation recorded during 1995 with the present condition. To identify floristic composition, species distribution and diversity, same location and same size of quadrates were selected in natural forest and planted or regenerated area as in previous study. Measurement and analytical tools for forest and vegetation reveled a total of 19 species and 341 individuals in 0.14 ha regenerated area and 18 species, 17 genera and 260 individuals in 0.16 ha, natural forest areas. However, in 1995, total 31 individuals of 20 woody species, 18 genera and 15 families were recorded within the sampling plots of 0.16 ha of natural forest. Moreover, Alnus nepalensis is found dominating regenerated area and Caryopteris odorata in natural forests whereas in 1995, Litsea chartacea and Maesa chisia were recorded dominant. The Shannon’s diversity H’ = 2.908, E = 0.970 and Var H’ = -0.00 and Simpsons D = 0.027 recorded in 1995 is found to be with higher values when compared with the analysis of present study. Furthermore, in comparison to 1995 study, this study showed lower basal area and timber volume with declining species diversity. Although, the natural forest is found with higher species composition compared to rehabilitated forest, species of herbs and shrubs were found extensively growing.
基金National Natural Science Foundation of China(41771098)Shandong Natural Science Foundation(ZR2014DQ028ZR2015DM004)
文摘To better ascertain leaf, stem and flower traits, and analyze aboveground allocation during the vegetation period, three sampling vegetation transects were settled and reed samples were collected at intervals to determine morphological parameters and dry and wet weights in Jiaozhou Bay wetland. Remote sensing data were also combined to evaluate regional biomass through EVI regression models. Results show that growth dynamics of leaves and stems changed during the vegetation period. Stem length increased rapidly and peaked in September（194.40 ± 23.89 cm）, whereas leaf width peaked in July. There was a significantly negative correlation between stem length and stem diameter with a value of-0.785. Stem biomass was higher than that of leaves, and the maximum value of aboveground biomass was 27.17 ± 3.56 g. F/C exhibited a tendency to increase and values ranged from 0.37–0.76. The aboveground biomass of sample plots reached a peak of 2356 ± 457 g/m^2 in September. EVI was 0.05–0.5; EVI and biomass had a better fitting effect using the power-exponent model compared with other models and its function was y = 4219.30 x^0.88（R^2 = 0.7810）. R^2 of the other three models ranked as linear function〉 polynomial function 〉exponent function, with the values being 0.7769, 0.7623 and 0.6963, respectively. EVI can be used to estimate vegetation biomass, and effectively solved the problems of the destructive effect to sample plots resulting from traditional harvest methods.
基金supported by the National Natural Science Foundation of China(Nos.41471176 and41130530)
文摘Plant growth contributes to mineral weathering, but this contribution remains poorly understood. Weathering rates in an aggrading forested watershed in subtropical China were studied by means of geochemical mass balance. Rainfall, dry deposition, and streamwater were monitored from March 2007 to February 2012. Samples of vegetative components, rainfall, dry deposition, streamwater, representative soils, and parent rock were collected and determined for mass balance calculation and clarifying plant-driven weathering mechanisms stoichiometrically. Ignoring biomass, weathering rates of Ca^2＋, Mg^2＋, Na^＋, and Si were 25.6, 10.7, 2.8, and 51.0 kg ha^-1 year^-1, respectively. Taking biomass into consideration, weathering rates of Ca^2＋, Mg^2＋, and Si and the sum of weathering rates of Ca^2＋, Mg^2＋, Na^＋, K^＋, and Si were 2.6, 1.8, 1.2, and 1.5-fold higher than those ignoring biomass, respectively. This is attributed to plant-driven weathering due to the nutrient （e.g., Ca^2＋, Mg^2＋, and K^＋） absorption by vegetation and substantial proton production during assimilation of these nutrients, with the former acting as a pump for removing weathering products and the latter being a source of weathering agents solubilizing mineral components. The same pattern of weathering, i.e., higher rates of weathering with than without including biomass in mass balance calculation, was reported in previous studies; however, the extent to which plants drive weathering rates varied with vegetation types and climatic zones. The documented biological weathering driven by plants is expected to play a critical role in regulating nutrient cycling and material flows within the Earth＇s Critical Zone.
