Inland wetlands in Abu Dhabi Emirate are wintering and stopover sites for migratory birds of prey. We conducted long-term regular monitoring surveys in Al Wathba Wetland Reserve (AWWR) from January 1995 to December 20...Inland wetlands in Abu Dhabi Emirate are wintering and stopover sites for migratory birds of prey. We conducted long-term regular monitoring surveys in Al Wathba Wetland Reserve (AWWR) from January 1995 to December 2022. Both diurnal and occasionally nocturnal surveys were undertaken to record the migratory raptors and owls in the Wetland Reserve. During the study, a total of 1282 regular monitoring visits were undertaken and 27 species of diurnal raptors and owls representing five families and three orders were detected. These represent 57% of the total species of birds of prey recorded in the UAE. Overall, 63% of all the species that we observed were Accipitriformes followed by 26% Falconiformes and 11% Strigiformes. We found that changes in mean daily temperature have a positive effect on raptor species diversity and abundance in the Wetland Reserve. The species encounter rate was higher in low temperature as compared to high temperature and overall regression equation was statistically significant F (4, 1126) = 8.49), p = 0.00). However, the numbers of raptors did not vary significantly across the years (p = 0.51). Western Marsh-harrier (Circus aeruginosus) and Greater Spotted Eagle (Clanga clanga) were recorded to be the most abundant species in the wetland reserve followed by Common Kestrel (Falco tinnunculus). However, the encounter rate of globally threatened Greater Spotted Eagle was detected to have significantly decreased since 2016. Moreover, 63% of the species detected were uncommon and rarely recorded such as 1) Saker Falcon 2) Lanner Falcon 3) Long-eared Owl & Merlin, which were the rare records from the wetland reserve. Furthermore, 27 years of regular monitoring in the wetland have yielded diverse diurnal raptors and owl fauna (H) = 0.83, (E) = 1.43 (Shannon Diversity Index). The results demonstrate that long-term monitoring surveys in arid environments are essential to determine the trends in the raptor populations and to document rare and globally important species.展开更多
Soil carbon(C), nitrogen(N) and phosphorus(P) concentrations and stoichiometries can be used to evaluate the success indicators to the effects of wetland restoration and reflect ecosystem function. Restoration of inla...Soil carbon(C), nitrogen(N) and phosphorus(P) concentrations and stoichiometries can be used to evaluate the success indicators to the effects of wetland restoration and reflect ecosystem function. Restoration of inland soda saline-alkali wetlands is widespread, however, the soil nutrition changes that follow restoration are unclear. We quantified the recovery trajectories of soil physicochemical properties, including soil organic carbon(SOC), total nitrogen(TN), and total phosphorus(TP) pools, for a chronosequence of three restored wetlands(7 yr, 12 yr and 21 yr) and compared these properties to those of degraded and natural wetlands in the western Songnen Plain, Northeast China. Wetland degradation lead to the loss of soil nutrients. Relative to natural wetlands, the mean reductions of in SOC, TN, and TP concentrations were 89.6%, 65.5% and 52.5%, respectively. Nutrients recovered as years passed after restoration. The SOC, TN, and TP concentrations increased by 2.36 times, 1.15 times, and 0.83 times, respectively in degraded wetlands that had been restored for 21 yr, but remained 29.2%, 17.3%, and 12.8% lower, respectively, than those in natural wetlands. The soil C∶N(RC N), C∶P(R CP), and N∶P(R NP) ratios increased from 5.92 to 8.81, 45.36 to 79.19, and 7.67 to 8.71, respectively in the wetland that had been restored for 12 yr. These results were similar to those from the natural wetland and the wetland that had been restored for 21 yr(P > 0.05). Soil nutrients changes occurred mainly in the upper layers(≤ 30 cm), and no significant differences were found in deeper soils(> 30 cm). Based on this, we inferred that it would take at least 34 yr for SOC, TN, and TP concentrations and 12 yr for RC N, R CP, and RN P in the top soils of degraded wetlands to recover to levels of natural wetlands. Soil salinity negatively influenced SOC(r =-0.704, P < 0.01), TN(r =-0.722, P < 0.01), and TP(r =-0.882, P < 0.01) concentrations during wetland restoration, which indicates that reducing salinity is beneficial to SOC展开更多
湿地生态系统是吸收全球大气二氧化碳(CO_(2))的汇,同时土壤厌氧环境造成其是大气甲烷(CH_(4))的源。尽管有证据表明,湿地生态系统CH_(4)排放部分抵消其对大气CO_(2)的净吸收,但目前未见全球尺度湿地CH_(4)排放对其净生态系统CO_(2)交换...湿地生态系统是吸收全球大气二氧化碳(CO_(2))的汇,同时土壤厌氧环境造成其是大气甲烷(CH_(4))的源。尽管有证据表明,湿地生态系统CH_(4)排放部分抵消其对大气CO_(2)的净吸收,但目前未见全球尺度湿地CH_(4)排放对其净生态系统CO_(2)交换(NEE)抵消效应的研究。本研究分析了全球内陆湿地(泥炭湿地和非泥炭湿地)以及滨海湿地(海草床、盐沼和红树林)中同时测定湿地NEE和CH_(4)排放通量的数据。结果表明:各类型湿地生态系统均为大气CO_(2)的汇,NEE值排序为红树林(-2011.0 g CO_(2)·m^(-2)·a^(-1))<盐沼(-1636.6 g CO_(2)·m^(-2)·a^(-1))<非泥炭地(-870.8 g CO_(2)·m^(-2)·a^(-1))<泥炭地(-510.7 g CO_(2)·m^(-2)·a^(-1))<海草床(-61.6 g CO_(2)·m^(-2)·a^(-1))。基于100年尺度CH_(4)全球变暖潜势将CH_(4)排放通量转换成CO_(2)当量通量(CO_(2)-eq flux)发现,CH_(4)排放分别抵消海草床、盐沼、红树林、非泥炭地和泥炭地生态系统净CO_(2)吸收的19.4%、14.0%、36.1%、64.9%和60.1%,而在未来20年尺度上,它们分别抵消CO_(2)吸收的57.3%、41.4%、107.0%、192.0%和177.3%,部分红树林、泥炭地和非泥炭地是净CO_(2)当量源。100年尺度各类湿地生态系统净温室气体平衡仍为负值,说明即使考虑CH_(4)排放,在100年尺度各类湿地生态系统仍为碳汇。明晰湿地生态系统CH_(4)排放主要调控机制并提出合理的减排对策,对于维系湿地生态系统碳汇功能,减缓气候变暖至关重要。展开更多
Taking a typical inland wetland of Honghe National Nature Reserve (HNNR), Northeast China, as the study area, this paper studied the application of L-band Synthetic Aperture Radar (SAR) image in extracting eco-hydrolo...Taking a typical inland wetland of Honghe National Nature Reserve (HNNR), Northeast China, as the study area, this paper studied the application of L-band Synthetic Aperture Radar (SAR) image in extracting eco-hydrological information of inland wetland. Landsat-5 TM and ALOS PALSAR HH backscatter images were first fused by using the wavelet-IHS method. Based on the fused image data, the classification method of support vector machines was used to map the wetland in the study area. The overall mapping accuracy is 77.5%. Then, the wet and dry aboveground biomass estimation models, including statistical models and a Rice Cloudy model, were established. Optimal parameters for the Rice Cloudy model were calculated in MATLAB by using the least squares method. Based on the validation results, it was found that the Rice Cloudy model produced higher accuracy for both wet and dry aboveground biomass estimation compared to the statistical models. Finally, subcanopy water boundary information was extracted from the HH backscatter image by threshold method. Compared to the actual water borderline result, the extracted result from L-band SAR image is reliable. In this paper, the HH-HV phase difference was proved to be valueless for extracting subcanopy water boundary information.展开更多
文摘Inland wetlands in Abu Dhabi Emirate are wintering and stopover sites for migratory birds of prey. We conducted long-term regular monitoring surveys in Al Wathba Wetland Reserve (AWWR) from January 1995 to December 2022. Both diurnal and occasionally nocturnal surveys were undertaken to record the migratory raptors and owls in the Wetland Reserve. During the study, a total of 1282 regular monitoring visits were undertaken and 27 species of diurnal raptors and owls representing five families and three orders were detected. These represent 57% of the total species of birds of prey recorded in the UAE. Overall, 63% of all the species that we observed were Accipitriformes followed by 26% Falconiformes and 11% Strigiformes. We found that changes in mean daily temperature have a positive effect on raptor species diversity and abundance in the Wetland Reserve. The species encounter rate was higher in low temperature as compared to high temperature and overall regression equation was statistically significant F (4, 1126) = 8.49), p = 0.00). However, the numbers of raptors did not vary significantly across the years (p = 0.51). Western Marsh-harrier (Circus aeruginosus) and Greater Spotted Eagle (Clanga clanga) were recorded to be the most abundant species in the wetland reserve followed by Common Kestrel (Falco tinnunculus). However, the encounter rate of globally threatened Greater Spotted Eagle was detected to have significantly decreased since 2016. Moreover, 63% of the species detected were uncommon and rarely recorded such as 1) Saker Falcon 2) Lanner Falcon 3) Long-eared Owl & Merlin, which were the rare records from the wetland reserve. Furthermore, 27 years of regular monitoring in the wetland have yielded diverse diurnal raptors and owl fauna (H) = 0.83, (E) = 1.43 (Shannon Diversity Index). The results demonstrate that long-term monitoring surveys in arid environments are essential to determine the trends in the raptor populations and to document rare and globally important species.
基金the auspices of National Key Research and Development Program of China(No.2016YFC05004)National Project of China(No.41971140)Science Foundation for Excellent Youth Scholars of Jilin Province(No.20180520097JH)。
文摘Soil carbon(C), nitrogen(N) and phosphorus(P) concentrations and stoichiometries can be used to evaluate the success indicators to the effects of wetland restoration and reflect ecosystem function. Restoration of inland soda saline-alkali wetlands is widespread, however, the soil nutrition changes that follow restoration are unclear. We quantified the recovery trajectories of soil physicochemical properties, including soil organic carbon(SOC), total nitrogen(TN), and total phosphorus(TP) pools, for a chronosequence of three restored wetlands(7 yr, 12 yr and 21 yr) and compared these properties to those of degraded and natural wetlands in the western Songnen Plain, Northeast China. Wetland degradation lead to the loss of soil nutrients. Relative to natural wetlands, the mean reductions of in SOC, TN, and TP concentrations were 89.6%, 65.5% and 52.5%, respectively. Nutrients recovered as years passed after restoration. The SOC, TN, and TP concentrations increased by 2.36 times, 1.15 times, and 0.83 times, respectively in degraded wetlands that had been restored for 21 yr, but remained 29.2%, 17.3%, and 12.8% lower, respectively, than those in natural wetlands. The soil C∶N(RC N), C∶P(R CP), and N∶P(R NP) ratios increased from 5.92 to 8.81, 45.36 to 79.19, and 7.67 to 8.71, respectively in the wetland that had been restored for 12 yr. These results were similar to those from the natural wetland and the wetland that had been restored for 21 yr(P > 0.05). Soil nutrients changes occurred mainly in the upper layers(≤ 30 cm), and no significant differences were found in deeper soils(> 30 cm). Based on this, we inferred that it would take at least 34 yr for SOC, TN, and TP concentrations and 12 yr for RC N, R CP, and RN P in the top soils of degraded wetlands to recover to levels of natural wetlands. Soil salinity negatively influenced SOC(r =-0.704, P < 0.01), TN(r =-0.722, P < 0.01), and TP(r =-0.882, P < 0.01) concentrations during wetland restoration, which indicates that reducing salinity is beneficial to SOC
文摘湿地生态系统是吸收全球大气二氧化碳(CO_(2))的汇,同时土壤厌氧环境造成其是大气甲烷(CH_(4))的源。尽管有证据表明,湿地生态系统CH_(4)排放部分抵消其对大气CO_(2)的净吸收,但目前未见全球尺度湿地CH_(4)排放对其净生态系统CO_(2)交换(NEE)抵消效应的研究。本研究分析了全球内陆湿地(泥炭湿地和非泥炭湿地)以及滨海湿地(海草床、盐沼和红树林)中同时测定湿地NEE和CH_(4)排放通量的数据。结果表明:各类型湿地生态系统均为大气CO_(2)的汇,NEE值排序为红树林(-2011.0 g CO_(2)·m^(-2)·a^(-1))<盐沼(-1636.6 g CO_(2)·m^(-2)·a^(-1))<非泥炭地(-870.8 g CO_(2)·m^(-2)·a^(-1))<泥炭地(-510.7 g CO_(2)·m^(-2)·a^(-1))<海草床(-61.6 g CO_(2)·m^(-2)·a^(-1))。基于100年尺度CH_(4)全球变暖潜势将CH_(4)排放通量转换成CO_(2)当量通量(CO_(2)-eq flux)发现,CH_(4)排放分别抵消海草床、盐沼、红树林、非泥炭地和泥炭地生态系统净CO_(2)吸收的19.4%、14.0%、36.1%、64.9%和60.1%,而在未来20年尺度上,它们分别抵消CO_(2)吸收的57.3%、41.4%、107.0%、192.0%和177.3%,部分红树林、泥炭地和非泥炭地是净CO_(2)当量源。100年尺度各类湿地生态系统净温室气体平衡仍为负值,说明即使考虑CH_(4)排放,在100年尺度各类湿地生态系统仍为碳汇。明晰湿地生态系统CH_(4)排放主要调控机制并提出合理的减排对策,对于维系湿地生态系统碳汇功能,减缓气候变暖至关重要。
基金Under the auspices of National High Technology Research and Development Program of China (No. 2007AA12Z176)National Natural Science Foundation of China (No. 40771170)Natural Science Foundation of Beijing (No. 8082010)
文摘Taking a typical inland wetland of Honghe National Nature Reserve (HNNR), Northeast China, as the study area, this paper studied the application of L-band Synthetic Aperture Radar (SAR) image in extracting eco-hydrological information of inland wetland. Landsat-5 TM and ALOS PALSAR HH backscatter images were first fused by using the wavelet-IHS method. Based on the fused image data, the classification method of support vector machines was used to map the wetland in the study area. The overall mapping accuracy is 77.5%. Then, the wet and dry aboveground biomass estimation models, including statistical models and a Rice Cloudy model, were established. Optimal parameters for the Rice Cloudy model were calculated in MATLAB by using the least squares method. Based on the validation results, it was found that the Rice Cloudy model produced higher accuracy for both wet and dry aboveground biomass estimation compared to the statistical models. Finally, subcanopy water boundary information was extracted from the HH backscatter image by threshold method. Compared to the actual water borderline result, the extracted result from L-band SAR image is reliable. In this paper, the HH-HV phase difference was proved to be valueless for extracting subcanopy water boundary information.
