The Three-River Headwater Region（TRHR）, known as the ＂Water Tower of China＂, is an important ecological shelter for national security interests and regional sustainable development activities for many downstream r...The Three-River Headwater Region（TRHR）, known as the ＂Water Tower of China＂, is an important ecological shelter for national security interests and regional sustainable development activities for many downstream regions in China and a number of Southeast Asian countries. The TRHR is a high-elevation, cold environment with a unique, but typical alpine vegetation system. Net primary productivity（NPP） is a key vegetation parameter and ecological indicator that can reflect both natural environmental changes and carbon budget levels. Given the unique geographical environment and strategic location of the TRHR, many scholars have estimated NPP of the TRHR by using different methods; however, these estimates vary greatly for a number of reasons. To date, there is no paper that has reviewed and assessed NPP estimation studies conducted in the TRHR. Therefore, in this paper, we（1） summarized the related methods and results of NPP estimation in the TRHR in a systematic review of previous research;（2） discussed the suitability of existing methods for estimating NPP in the TRHR and highlighted the most significant challenges; and（3） assessed the estimated NPP results. Finally, developmental directions of NPP estimation in the TRHR were prospected.展开更多
This study aimed at using nine ecological parameters in evaluating the quality of the Tigris River for public usage, by choosing five sampling sites along the river in Baghdad area. These parameters included temperatu...This study aimed at using nine ecological parameters in evaluating the quality of the Tigris River for public usage, by choosing five sampling sites along the river in Baghdad area. These parameters included temperature, pH, the saturated ratio by dissolved oxygen (%sat), biological oxygen demand (BOD5), nitrate (NO3?1), phosphate (PO4?3), fecal coliform (FC) turbidity and total dissolved solids (TDS), and these parameters were used for calculating overall water quality index in the Tigris River at study area. The results showed high values of turbidity and TDS, as well as high count of FC in all study stations, while other studied parameters were within permissible limit defined by world health organization and Iraqi criteria. The results of the overall water quality index indicated that the Tigris River was in class medium, therefore the Tigris River water in study area is relatively not safe for direct domestic use in all seasons.展开更多
The ecological characteristics of four lizardfishes, Trachinocephalus myops, Saurida undosquamis, Saurida tumbil and Saurida elongata, were studied from specimens （910 T. myops, 454 S. un-dosquamis, 686 S. tumbil and...The ecological characteristics of four lizardfishes, Trachinocephalus myops, Saurida undosquamis, Saurida tumbil and Saurida elongata, were studied from specimens （910 T. myops, 454 S. un-dosquamis, 686 S. tumbil and 744 S. elongata） collected monthly in the southern Taiwan Straits from April 2005 to March 2006. The population dynamics of the four lizardfishes was also discussed by the comparison with the previous studies. All being composed of 7 a classes; the dominant group of T. myops and S. tumbil was 1–2 a, while S. undosquamis and S. elongate were 2–3 a. The total mortality coefficient Z and the fishing mortality F were at high as indicated by the exploitation ratio E（0.5）, and a large number of by-caught juvenile and young fishes showing that the stock of lizardfishes in this area was overexploited and the fishing gear was irrational. Compared with the previous studies, the maximum and mean fork length, body mass and age of the four lizard- fishes declined gradually, the lizardfishes populations were younger in age and smaller in size. The asymptotic fork length L ∞ decreased while increasing growth coefficient k, and age at the inflexion point of mass t r was younger compared with the previous studies. The declining of older ones has moderated the feeding competition and the younger ones grew faster. The larger mortality param-eters Z, M and F have revealed higher fishing pressure. The smaller change of the first mature fork length of female T . myops and the change from K selection pattern to r selection pattern of S. tumbil have indicated a more vulnerable fishery ecosystem in this area. The changes of ecological characteristics and population dynamics may be caused by over-exploitation of demersal fishes such as the lizardfishes, especially a large number of juvenile and young fishes by-catch by the current fishing gears and methods. Therefore, in addition to the traditional fishery management approach such as the minimum length-limit, ecosystem approach to fisheries management （EAF） 展开更多
The benthic ostracods of Red Sea of Egypt have received little attention in ecological studies. Temperature, depth, salinity, dissolved oxygen, pH, conductivity, and other environmental variables all have an impact on...The benthic ostracods of Red Sea of Egypt have received little attention in ecological studies. Temperature, depth, salinity, dissolved oxygen, pH, conductivity, and other environmental variables all have an impact on benthic ostracods. This study aimed to determine the influence of environmental parameters on the distribution of benthic ostracods by determining the similarity and dissimilarity between the eight collection sites, investigating the regional distribution form by accomplished Multidimensional Scaling (MDS), and recognizing the percentage of the influence of each species on the resemblances and variances within the clusters formed by SIMPER analysis, determining the relationships between depth and other factors by Spearman’s rank correlation coefficient. A total of 43 ostracod species had been identified. According to the frequency index, a single species was rare, six were common and the remaining species (36) were dominant. Seven ostracods species were found across all sites and Cytherelloidea sp. was found in two. The abundance and richness of ostracod species were correlated positively with water temperature, dissolved oxygen, organic matter, salinity, and calcium carbonate. The cold water is preferred by the ostracods Cylindroleberis vix and Prionotoleberis lux and the warm water is favored by podocopid ostracods. The findings of this study will aid in the identification of ostracod species, as well as understanding the characteristics and ecological variables in this zone of the Red Sea in Egypt. The current investigation is an attempt to shed the light on the features of ostracods that live on the east side of Safaga Island.展开更多
为了准确监测和客观评估稻纵卷叶螟对水稻生长发育和产量形成的危害,利用ASD Field Spec3地物波谱仪和SPAD-502叶绿素仪分别采集控制大田试验(2015年和2019年)和自然大田试验(2020年)在各生育期(拔节期、孕穗期、灌浆期、成熟期)水稻的...为了准确监测和客观评估稻纵卷叶螟对水稻生长发育和产量形成的危害,利用ASD Field Spec3地物波谱仪和SPAD-502叶绿素仪分别采集控制大田试验(2015年和2019年)和自然大田试验(2020年)在各生育期(拔节期、孕穗期、灌浆期、成熟期)水稻的冠层高光谱数据和SPAD值,调查采集样点的虫量和水稻卷叶率,对比分析两种试验中稻纵卷叶螟的虫害发生特征、水稻冠层光谱特征和水稻生理生态参数特征,建立基于高光谱参数的水稻受稻纵卷叶螟危害的生理生态参数估算模型。结果表明,(1)两种试验的水稻SPAD值和冠层的红边至近红外波段的反射率均随着稻纵卷叶螟虫害程度的加重而降低,而可见光波段的反射率则相反;(2)自然大田试验的SPAD值和红光至近红外波段的冠层反射率在水稻生长发育前期要显著低于控制大田试验,而到了后期则反而要略高于控制大田试验;(3)综合分析筛选出自然大田试验和控制大田试验中的多个虫害特征参数和植被指数分别构建出了SPAD的单因子和多因子估算模型,各模型均达到了较好的估算效果,在单因子模型中EVI的二项式函数模拟效果最好,而多因子线性回归估测模型的模拟效果优于所有的单因子模型;(4)通过2021年对这些模型的应用检验发现:这些模型中基于虫量、卷叶率、OSAVI、EVI和DVI的单因子估算模型的SPAD估算值与实测值拟合度很高,其Rv 2均超过了0.8,达到了比较理想的估算效果,这为稻纵卷叶螟危害下的水稻SPAD值估测提供了一种精度较高且可行的估算方法。展开更多
基金National Key Research and Development Program of China,No.2016YFC0500205National Basic Research Program of China(973 Program),No.2015CB954103,No.2015CB954101
文摘The Three-River Headwater Region（TRHR）, known as the ＂Water Tower of China＂, is an important ecological shelter for national security interests and regional sustainable development activities for many downstream regions in China and a number of Southeast Asian countries. The TRHR is a high-elevation, cold environment with a unique, but typical alpine vegetation system. Net primary productivity（NPP） is a key vegetation parameter and ecological indicator that can reflect both natural environmental changes and carbon budget levels. Given the unique geographical environment and strategic location of the TRHR, many scholars have estimated NPP of the TRHR by using different methods; however, these estimates vary greatly for a number of reasons. To date, there is no paper that has reviewed and assessed NPP estimation studies conducted in the TRHR. Therefore, in this paper, we（1） summarized the related methods and results of NPP estimation in the TRHR in a systematic review of previous research;（2） discussed the suitability of existing methods for estimating NPP in the TRHR and highlighted the most significant challenges; and（3） assessed the estimated NPP results. Finally, developmental directions of NPP estimation in the TRHR were prospected.
文摘This study aimed at using nine ecological parameters in evaluating the quality of the Tigris River for public usage, by choosing five sampling sites along the river in Baghdad area. These parameters included temperature, pH, the saturated ratio by dissolved oxygen (%sat), biological oxygen demand (BOD5), nitrate (NO3?1), phosphate (PO4?3), fecal coliform (FC) turbidity and total dissolved solids (TDS), and these parameters were used for calculating overall water quality index in the Tigris River at study area. The results showed high values of turbidity and TDS, as well as high count of FC in all study stations, while other studied parameters were within permissible limit defined by world health organization and Iraqi criteria. The results of the overall water quality index indicated that the Tigris River was in class medium, therefore the Tigris River water in study area is relatively not safe for direct domestic use in all seasons.
基金Marine Public Welfare Project of China under contract Nos 200805065,200905019-6,200705029 and 200805064Chinese Off shore Investigation and Assessment under contract No.908-02-04008+1 种基金the Scientific Research Foundation of the Third Institute of Oceanography,SOA under contract No.2011006Marine Science Foundation for Young Scientist under contract No.2011143
文摘The ecological characteristics of four lizardfishes, Trachinocephalus myops, Saurida undosquamis, Saurida tumbil and Saurida elongata, were studied from specimens （910 T. myops, 454 S. un-dosquamis, 686 S. tumbil and 744 S. elongata） collected monthly in the southern Taiwan Straits from April 2005 to March 2006. The population dynamics of the four lizardfishes was also discussed by the comparison with the previous studies. All being composed of 7 a classes; the dominant group of T. myops and S. tumbil was 1–2 a, while S. undosquamis and S. elongate were 2–3 a. The total mortality coefficient Z and the fishing mortality F were at high as indicated by the exploitation ratio E（0.5）, and a large number of by-caught juvenile and young fishes showing that the stock of lizardfishes in this area was overexploited and the fishing gear was irrational. Compared with the previous studies, the maximum and mean fork length, body mass and age of the four lizard- fishes declined gradually, the lizardfishes populations were younger in age and smaller in size. The asymptotic fork length L ∞ decreased while increasing growth coefficient k, and age at the inflexion point of mass t r was younger compared with the previous studies. The declining of older ones has moderated the feeding competition and the younger ones grew faster. The larger mortality param-eters Z, M and F have revealed higher fishing pressure. The smaller change of the first mature fork length of female T . myops and the change from K selection pattern to r selection pattern of S. tumbil have indicated a more vulnerable fishery ecosystem in this area. The changes of ecological characteristics and population dynamics may be caused by over-exploitation of demersal fishes such as the lizardfishes, especially a large number of juvenile and young fishes by-catch by the current fishing gears and methods. Therefore, in addition to the traditional fishery management approach such as the minimum length-limit, ecosystem approach to fisheries management （EAF）
文摘The benthic ostracods of Red Sea of Egypt have received little attention in ecological studies. Temperature, depth, salinity, dissolved oxygen, pH, conductivity, and other environmental variables all have an impact on benthic ostracods. This study aimed to determine the influence of environmental parameters on the distribution of benthic ostracods by determining the similarity and dissimilarity between the eight collection sites, investigating the regional distribution form by accomplished Multidimensional Scaling (MDS), and recognizing the percentage of the influence of each species on the resemblances and variances within the clusters formed by SIMPER analysis, determining the relationships between depth and other factors by Spearman’s rank correlation coefficient. A total of 43 ostracod species had been identified. According to the frequency index, a single species was rare, six were common and the remaining species (36) were dominant. Seven ostracods species were found across all sites and Cytherelloidea sp. was found in two. The abundance and richness of ostracod species were correlated positively with water temperature, dissolved oxygen, organic matter, salinity, and calcium carbonate. The cold water is preferred by the ostracods Cylindroleberis vix and Prionotoleberis lux and the warm water is favored by podocopid ostracods. The findings of this study will aid in the identification of ostracod species, as well as understanding the characteristics and ecological variables in this zone of the Red Sea in Egypt. The current investigation is an attempt to shed the light on the features of ostracods that live on the east side of Safaga Island.
文摘为了准确监测和客观评估稻纵卷叶螟对水稻生长发育和产量形成的危害,利用ASD Field Spec3地物波谱仪和SPAD-502叶绿素仪分别采集控制大田试验(2015年和2019年)和自然大田试验(2020年)在各生育期(拔节期、孕穗期、灌浆期、成熟期)水稻的冠层高光谱数据和SPAD值,调查采集样点的虫量和水稻卷叶率,对比分析两种试验中稻纵卷叶螟的虫害发生特征、水稻冠层光谱特征和水稻生理生态参数特征,建立基于高光谱参数的水稻受稻纵卷叶螟危害的生理生态参数估算模型。结果表明,(1)两种试验的水稻SPAD值和冠层的红边至近红外波段的反射率均随着稻纵卷叶螟虫害程度的加重而降低,而可见光波段的反射率则相反;(2)自然大田试验的SPAD值和红光至近红外波段的冠层反射率在水稻生长发育前期要显著低于控制大田试验,而到了后期则反而要略高于控制大田试验;(3)综合分析筛选出自然大田试验和控制大田试验中的多个虫害特征参数和植被指数分别构建出了SPAD的单因子和多因子估算模型,各模型均达到了较好的估算效果,在单因子模型中EVI的二项式函数模拟效果最好,而多因子线性回归估测模型的模拟效果优于所有的单因子模型;(4)通过2021年对这些模型的应用检验发现:这些模型中基于虫量、卷叶率、OSAVI、EVI和DVI的单因子估算模型的SPAD估算值与实测值拟合度很高,其Rv 2均超过了0.8,达到了比较理想的估算效果,这为稻纵卷叶螟危害下的水稻SPAD值估测提供了一种精度较高且可行的估算方法。
