The East China Sea(ECS)off the Coast of Zhoushan Archipelago,Zhejiang(ECS-CZA)is home to abundant fishery resources and an important spawning,feeding,and nursing ground for a variety of fish species.Due to long-term o...The East China Sea(ECS)off the Coast of Zhoushan Archipelago,Zhejiang(ECS-CZA)is home to abundant fishery resources and an important spawning,feeding,and nursing ground for a variety of fish species.Due to long-term overfishing,the ichthyoplankton structure has been dramatically altered.Understanding the species composition and distribution of fish eggs and larvae is one of the most essential tasks to accurately regulate fishery resources and formulate effective management policies;however,little is known about the ichthyoplankton in this region.In this study,an integrated strategy of morphology identification(MI)and mitochondrial COI DNA barcoding was used to identify species of fish eggs and larvae collected from the ECSCZA.MI revealed 15 fish egg species belonging to 12 families and 12 fish larva species belonging to 12 families;in contrast,DNA barcoding altogether identified 30 species,including 18 fish egg species and 13 fish larva species.One species was shared between the egg and larva samples.Our study offers useful tools and critical scientific information for further understanding the diversity,distribution,and conservation management of various ichthyoplankton species in the marine environment.展开更多
Nestedness is one of the important patterns in island biogeography,community ecology and conservation biology.However,most previous nestedness studies focus on the taxonomic dimension while neglecting the functional a...Nestedness is one of the important patterns in island biogeography,community ecology and conservation biology.However,most previous nestedness studies focus on the taxonomic dimension while neglecting the functional and phylogenetic processes in generating nestedness.Moreover,few studies have examined the seasonal change of the nestedness and underlying processes.Here,we examined the seasonal nestedness of bird assemblages in taxonomic,functional,and phylogenetic dimensions,and determined the underlying processes of nestedness patterns in the Zhoushan Archipelago,China.We surveyed the occurrence, abundance,and habitats of birds on 40 islands.We calculated taxonomic,functional,and phylogenetic nestedness using WNODF and treeNODF.We determined the processes underlying nestedness by relating nestedness ranks to island characteristics and species traits.The WNODF analyses showed that bird assemblages in winter and summer were both significantly nested.The habitat-by-site matrix was also significantly nested.The nestedness of bird assemblages was significantly correlated with island area,habitat diversity,habitat specificity,minimum area requirement,habitat specificity and hand-wing index(HWI) of birds in both seasons.While the distance to the nearest mainland(DTM) exerted the influence on nestedness in summer,the distance to the nearest larger island(DTNL)affected nestedness only in winter.However,the nestedness of bird assemblages was not caused by passive sampling or human disturbance.The results of treeNODF analyses illustrated that bird assemblages were functionally and phylogenetically nested in summer and winter,but the exact mechanisms were somewhat different in these two seasons.Overall,our results supported the habitat nestedness hypothesis,selective extinction hypothesis,and selective colonization hypothesis in both seasons.From a conservation viewpoint,we should protect islands with large area and diverse habitats,islands close to the mainland,and species with large area requirement and high habitat specificity to prevent local extinction.展开更多
Macrobenthic organisms are commonly employed as biomonitors for environmental risk assessment.In this study,we aimed to investigate the spatial and temporal patterns of the macrobenthic community,which is influenced b...Macrobenthic organisms are commonly employed as biomonitors for environmental risk assessment.In this study,we aimed to investigate the spatial and temporal patterns of the macrobenthic community,which is influenced by environmental factors of sediments and bottom water layer.We sampled a total of 12,11,10,and 11 stations in the Shengsi Archipelago during June 2010,August 2010,November 2020,and April 2021 respectively.A total of 124 species of macrobenthos were identified,with polychaetes being the dominant group.The abundance,biomass,and diversity indices exhibited no significant temporal differences.Similarly,biodiversity did not exhibit a clear spatial gradient,likely due to the small study area and the absence of significant differences in key factors such as depth.However,the stations with the lowest biodiversity values consistently appeared in the southwest region,possibly due to the impact of human activities.Significant differences in the macrobenthic community were observed between all months except between June and August,and mollusk Endopleura lubrica and polychaete Sigambra hanaokai were important contributors to these differences according to the results of the Similarity Percentages analysis.Suspended particulate matter(SPM)was identified as the primary driving factors of macrobenthic variability.In summary,the community structure underwent temporal changes influenced by complex current patterns,while biodiversity remained relatively stable.This study contributes to our understanding of the key environmental factors affecting macrobenthic communities and biodiversity.It also provides valuable data support for the long-term monitoring of macrobenthos and the environment in the Shengsi Archipelago.展开更多
Studying coexistence mechanisms is practically important for understanding and conserving marine biodiversity and community structure. Tropical marine ecosystems may exhibit higher competition between top predators du...Studying coexistence mechanisms is practically important for understanding and conserving marine biodiversity and community structure. Tropical marine ecosystems may exhibit higher competition between top predators due to generally low primary productivity and pronounced seasonal fluctuation in food availability. Consequentially, niche segregation in sympatric breeding seabirds is expected to occur as a mechanism to maintain species coexistence. However, a single-dimensional study on seabird niche segregation might result in unclear niche overlap. Here, we investigated multi-dimensional niche segregation of tropical seabirds during field expeditions to the Xisha Archipelago, China, in 2023. We reconfirmed the breeding status of six species of terns and noddy, and further revealed the multi-dimensional niche segregation among Black-naped (Sterna sumatrana), Bridled (Onychoprion anaethetus) and Roseate (Sterna dougallii) Terns. Spatially, these three species utilized nest sites that differentiated by vegetation and distance to sea. Temporally, Black-naped Terns bred earlier and for a longer period, while Bridled and Roseate Terns had more restricted breeding seasons. Furthermore, the daily foraging activity patterns of these species also differed, with Bridled Terns potentially having a longer foraging time at noon. In terms of diet, Bridled Terns were opportunists that fed on fishes, squids and insects, such as migratory fruit-piercing moths, while Roseate Terns were primarily piscivorous, especially feeding on Exocoetidae (flying fishes). Seabirds play a crucial role in marine ecosystems and are globally threatened. Our findings shed light on the complex mechanisms facilitating the coexistence of sympatric seabird species in China. Further research is needed to examine other ecological interactions and to develop effective conservation strategies for protecting these valuable seabird populations.展开更多
Nested subset pattern(nestedness)is an important part of the theoretical framework of island biogeography and community ecology.However,most previous studies often used nestedness metrics or randomization algorithms t...Nested subset pattern(nestedness)is an important part of the theoretical framework of island biogeography and community ecology.However,most previous studies often used nestedness metrics or randomization algorithms that are vulnerable to type I error.In this study,we inves-tigated the nestedness of lizard assemblages on 37 islands in the Zhoushan Archipelago,China.We used the line-transect method to survey species occurrence,abundance,and habitat types of lizards on 37 islands during 2 breeding seasons in 2021 and 2022.We applied the nested metric WNODF and the conservative rc null model to control for type I error and quantify the significance of nestedness.Spearman rank cor relations were used to evaluate the role of 4 habitat variables(island area,2 isolation indices,and habitat diversity)and 4 ecological traits(body size,geographic range size,clutch size,and minimum area requirement)in generating nestedness.The results of WNODF analyses showed that lizard assemblages were significantly nested.The habitat-by-site matrix estimated by the program NODF was also significantly nested,support-ing the habitat nestedness hypothesis.The nestedness of lizard assemblages were significantly correlated with island area,habitat diversity.clutch size,and minimum area requirement.Overall,our results suggest that selective extinction and habitat nestedness were the main drivers of lizard nestedness in our system.In contrast,the nestedness of lizard assemblages was not due to passive sampling or selective colonization.To maximize the number of species preserved,our results indicate that we should protect both large islands with diverse habitats and species with largearea requirement and clutch size.展开更多
Nestedness is an important part of the theoretical framework of island biogeography and community ecology.However,most previous studies focused on taxonomic dimension and overlooked functional and phylogenetic nestedn...Nestedness is an important part of the theoretical framework of island biogeography and community ecology.However,most previous studies focused on taxonomic dimension and overlooked functional and phylogenetic nestedness.Here,we simultaneously investigated taxonomic,functional,and phylogenetic nestedness of terrestrial mammals on 39 land-bridge islands in the Zhoushan Archipelago,China.As mammals’response to the environment may depend on their body size,we performed analyses for three mammal assemblages separately:overall species,large and medium-sized species,and small species.The taxonomic nestedness was quantified by organizing the species incidence matrix,while the functional and phylogenetic nestedness were estimated by combining the similarity of their ecological traits and phylogeny.Island characteristics(island area,three isolation indices,land use intensity,and habitat diversity)and species traits(body size,litter size,habitat specificity,geographic range size,and minimum area requirement)were used as predictors of nestedness.Overall and small species were significantly nested in 3 facets of nestedness,and results supported the selective extinction,selective colonization,and habitat nestedness hypotheses.Large and medium-sized species were functionally and phylogenetically nested when matrices were ordered by increasing distance to mainland,supporting the selective colonization hypothesis.Overall,differences in nestedness and its underlying mechanisms were detected not only in 3 facets of nestedness but also in the 3 mammal assemblages.Therefore,frameworks that incorporate taxonomic,phylogenetic,and functional nestedness can contribute to a more comprehensive understanding of nestedness processes.Additionally,it also improves our ability to understand the divergent responses of mammal assemblages to the insular environment.展开更多
The archipelagic waters system is stipulated in the United Nations Convention on the Law of the Sea. It is closely related to China＇s marine legislation and maritime law enforcement. It is not only related to the int...The archipelagic waters system is stipulated in the United Nations Convention on the Law of the Sea. It is closely related to China＇s marine legislation and maritime law enforcement. It is not only related to the integrity of our country＇s national sovereignty, but also to the maintenance of our maritime rights and interests. However, there is no comprehensive fundamental law governing the overall situation of marine development in our country, also no relevant legal code on the archipelagic waters system. Therefore, we should learn from the world＇s marine legislation and practice which the archipelagic waters system was written into China＇s marine legislation.展开更多
Fourteen isolated drowned reefs have been identified around the Xisha Uplift by multibeam and seismic data. The drowning processes of these reefs can be divided into three different stages, which correspond to three d...Fourteen isolated drowned reefs have been identified around the Xisha Uplift by multibeam and seismic data. The drowning processes of these reefs can be divided into three different stages, which correspond to three different accelerated tectonic subsidence periods. The drowning of the Xisha reefs is the result of the combined action of tectonic subsidence and sea level fluctuations, and the tectonic subsidence rate had to remain above 0.2 mm yr^(-1 )for a long time. Three abrupt accelerated tectonic subsidence events that occurred in the late Miocene, Pliocene and early Quaternary in the Xisha Uplift were closely related to the thermal subsidence processes after three stages of post-rifting magmatism. The magmatism of the middle Miocene and the following thermal subsidence resulted in the drowning of reefs in the northwestern Xisha uplift(Zone A). During the early Pliocene, massive magmatic intrusions and volcanic eruptions occurred in the Xisha Uplift. Then, the subsequent thermal subsidence started the drowning process of reefs in the northeastern and western regions of the Xisha Uplift(Zone B and C). During the early Quaternary, large-scale magmatism also occurred in the Xisha Uplift. The subsequent thermal subsidence resulted in a new rapid tectonic subsidence, which caused the reefs in the southern and southeastern regions of the Xisha Uplift to drown(Zone D and E).展开更多
The community structure of intertidal macrobenthos in Changdao Archipelago(north of Shandong Peninsula,between Bohai Bay and the northern Yellow Sea) was examined based on samples collected from 14 stations in five tr...The community structure of intertidal macrobenthos in Changdao Archipelago(north of Shandong Peninsula,between Bohai Bay and the northern Yellow Sea) was examined based on samples collected from 14 stations in five transects in June 2007.Three stations corresponding to high,medium and low tidal areas were set up for each transect.A total of 68 macrobenthic species were found in the research region,most of which belonged to Mollusca and Crustacea.The average abundance and biomass of the macrobenthos was 1 383 ind./m2 and 372.41 g/m2,respectively.The use of an arbitrary similarity level of 20% resulted in identification of five groups among the 14 stations in the research region.There were remarkable differences in the biomass,abundance and Shannon-Wiener diversity index of the different sediments.Specifically,the order of biomass was rocky shores > gravel > mud-sand > coarse sand > stiff mud,while the order of abundance was rocky shores > coarse sand > mud-sand > gravel > stiff mud,and that of the diversity index was mud-sand > gravel > stiff mud > rocky shores > coarse sand.The above results revealed that the sediment type was the most important factor affecting the structure of the macrobenthic community of the intertidal zone.展开更多
The transport mechanism and settlement characteristics of suspended sediments are analyzed in this article on the basis of measured data. Results indicate that the concentration and flux of suspended sediments decreas...The transport mechanism and settlement characteristics of suspended sediments are analyzed in this article on the basis of measured data. Results indicate that the concentration and flux of suspended sediments decrease sharply from Hangzhou Bay to the offshore area. Suspended sediment transport is mainly controlled by advection transport and gravitational circulation transport. The settling velocity of suspended sediments gradually decreases from Hangzhou Bay to the offshore area. The settlement of suspended sediments mainly takes place during the turning phase of the tidal currents.展开更多
The modern landscape patterns of islands usually show obvious spatial heterogeneity and complex ecological effects due to the vulnerability of ecosystems with natural characteristics under increasing human activities....The modern landscape patterns of islands usually show obvious spatial heterogeneity and complex ecological effects due to the vulnerability of ecosystems with natural characteristics under increasing human activities.In this work,we studied the variation in landscape pattern of the Miaodao Archipelago in Bohai Sea,North China,from 1990 to 2019,and an evaluation index system was established to explore the impacts of natural conditions and human disturbances on the ecological effects in the pressure-state-response(PSR)framework.Empirical analysis was conducted on the natural conditions,human disturbances,and ecological effects.The results show that forest was the main component of the landscape pattern in the archipelago.Both of the areas offorest and construction land were increasing,and the areas of cropland and grassland were declining.Other landscape types changed slightly,and the landscape fragmentation was increasing.The natural condition exhibited positive effects while human disturbance showed negative effects on the local ecology.Human disturbances come mainly from shoreline use while the natural conditions were mainly from the elevation change.The ecological effects were resulted mainly from the net primary productivity and water yield.展开更多
To study the water quality influenced by the anthropogenic activities and its impact on the phytoplankton diversity in the surface waters of Miaodao Archipelago, the spatiotemporal variations in phytoplankton communit...To study the water quality influenced by the anthropogenic activities and its impact on the phytoplankton diversity in the surface waters of Miaodao Archipelago, the spatiotemporal variations in phytoplankton communities and the environmental properties of the surface waters surrounding the Five Southern Islands of Miaodao Archipelago were investigated, based on seasonal field survey conducted from November 2012 to August 2013. During the survey, a total of 109 phytoplankton species from 3 groups were identified in the southern waters of Miaodao Archipelago, of which 77 were diatoms, 29 were dinoflagellates, and 3 were chrysophytes. Species number was higher in winter（73）, moderate in autumn（70）, but lower in summer（31） and spring（27）. The species richness index in autumn（5.92） and winter（4.28） was higher than that in summer（2.83） and spring（1.41）.The Shannon-Wiener diversity index was high in autumn（2.82）, followed by winter（1.99） and summer（1.92）, and low in spring（0.07）. The species evenness index in autumn（0.46） and summer（0.39） was higher than that in winter（0.32） and spring（0.02）. On the basis of principal component analysis（PCA） and redundancy analysis（RDA）, we found that dissolved inorganic nitrogen（DIN） and chemical oxygen demand（COD） in spring, COD in summer, p H in autumn, and salinity and oil pollutant in winter, respectively, showed the strongest association with the distribution of phytoplankton diversity. The spatial heterogeneity of the southern waters of Miaodao Archipelago was quite obvious, and three zones, i.e., northeastern, southwestern and inter-island water area, were identified by cluster analysis（CA） based on key environmental variables.展开更多
Ground Penetrating Radar （GPR） measurements of sea ice thickness including undeformed ice and ridged ice were carried out in the central north Canadian Archipelago in spring 2010. Results have shown a significant sp...Ground Penetrating Radar （GPR） measurements of sea ice thickness including undeformed ice and ridged ice were carried out in the central north Canadian Archipelago in spring 2010. Results have shown a significant spatial heterogeneity of sea ice thickness across the shelf. The undeformed multi-year fast ice of （2.05±0.09） m thick was investigated southern inshore zone of Borden island located at middle of the observational section, which was the observed maximum thickness in the field work. The less thick sea ice was sampled across a flaw lead with the thicknesses of （1.05±0.11） m for the pack ice and （1.24±0.13） m for the fast ice. At the northernmost spot of the section, the undeformed multi-year pack ice was （1.54±0.22） m thick with a ridged ice of 2.5 to 3 m, comparing to the multi-year fast ice with the thickness of （1.67±0.16） m at the southernmost station in the Prince Gustaf Adolf Sea.展开更多
Research on carrying capacity, aiming at maintaining the limited ability of the Earth＇s life supporting system to sustain human development, requires a comprehensive and ecosystem-based approach to monitor and assess...Research on carrying capacity, aiming at maintaining the limited ability of the Earth＇s life supporting system to sustain human development, requires a comprehensive and ecosystem-based approach to monitor and assess the localized sustainability of coupled social and ecological systems. A definition termed the ecosystem-based carrying capacity of island（EBCCI） was developed in this paper of which the indices of fundamental and realized carrying capacities of island（FCCI and RCCI） were highlighted to emphasize the inter-dependencies between social systems and ecological systems. In order to avoid the difficulties and uncertainties of direct assessment, the related assessment model was established on the basis of synthetic evaluation of inherent and external factors affecting the EBCCI. The southern Miaodao Archipelago（SMA） located in the intersection of the Bohai Sea and the Yellow Sea, China, was taken as a typical example to acquire integrated recognition of the island ecosystem and its carrying capacity so as to discuss its sustainable development. The index scores of FCCI and RCCI in the SMA were 0.818 5 and 0.712 9 out of 1.0, respectively, with acceptable uncertainties. The results showed a relatively well capacity to sustain progress and relatively well realization of the carrying capacity of island ecosystem, owing to a well capacity of ecologically regulating, general performance of both ecologically supporting and resource provisioning, and a relatively high level of social supporting system. The study implied that it was critical to optimize the inter-dependencies and to sustain the relative balance between social systems and ecological systems so as to improve the RCCI and further facilitate the sustainability of SMA. The approach proposed in this paper provides a powerful tool which is well applicative to the regional level of an oceanic island or archipelago to study the sustainable development and can be further popularized to the coastal zone.展开更多
Several significant events of a geological nature occurred approximately 800 ka before the present: (1) Australasian tektite fall (AA), (2) Brunhes-Matuyama geomagnetic reversal (BMR), (3) mid-Pleistocene changes in i...Several significant events of a geological nature occurred approximately 800 ka before the present: (1) Australasian tektite fall (AA), (2) Brunhes-Matuyama geomagnetic reversal (BMR), (3) mid-Pleistocene changes in ice age cycles. Add to these the undated fault system (4) in the South-West (SW) of the South China Sea (SCS). Here we offer a unified cause for all four of these in (5), an impact in the SCS of a large, massive cosmic object, likely a comet, obliquely coming from the SW at an extremely shallow angle, striking the Sunda shelf yet unexploded with the shock of its compressed air bow wave, and causing the continual shelf and slope to collapse, resulting in the fault system (4), then traveling almost tangentially to the surface, exploding at impact with the sea surface, ejecting the tektites (1), creating the formation underlying the later atolls of Spratlies Archipelago (6), Nansha Islands in Chinese, & causing the BMR (2). An explanation of event (3) was Richard Muller’s hypothesis of planet Earth passing through an interplanetary dust cloud periodically due to ecliptic precession. Here we hypothesize this cloud actually is a belt of Australasian tektites ejected into space at super-orbital velocities that Earth encounters about every 100 ka.展开更多
Based on the general and concrete principles of index system of marine economy and the choices of the evaluation index, this paper analyzes the index importance by means of AHP and establishes a set of the evaluation ...Based on the general and concrete principles of index system of marine economy and the choices of the evaluation index, this paper analyzes the index importance by means of AHP and establishes a set of the evaluation index system of marine economy in the Zhoushan Archipelago New District, to which an overall analysis and appraisal is given. The main factors that have limited the sustainable development of marine economy, in combination with the factors that influence its development, are put forward in accordance with its connotation of sustainable development of marine economy and sustainable development strategy based on marine tourism development.展开更多
Knowledge of the sediment flux derived from different sources is critical for interpreting the sedimentary records associated with large river sedimentary systems. For the Changjiang River system, previous studies har...Knowledge of the sediment flux derived from different sources is critical for interpreting the sedimentary records associated with large river sedimentary systems. For the Changjiang River system, previous studies hardly focused on the sediment load from the adjacent Zhoushan Archipelago(ZA). Based on four prediction models, aiming to improve the understanding of the sediment load from the ZA during the Holocene, we show that the predicted sediment flux of the ZA ranges from ~0.7 to 26.5 Mt·yr^(-1), with an average value of 10.7 Mt·yr^(-1), and the islands with a relatively large area or high relief contribute greatly to the total flux. This sediment load is an order of magnitude lower than that of the Changjiang River, but it is similar to those of the local small rivers. Located in the core area of the southward dispersal path of the Changjiang River plume, the ZA also influences the sediment transport into Hangzhou Bay and over the Zhejiang-Fujian coastal seas. On the Holocene temporal scale, e.g., for the period from 6 ka BP to 2 ka BP, the sediments discharged from the ZA had a considerable effect on the shelf sedimentary system. This study provides evidence for an important role an archipelago can play in terms of sediment supply and transport in coastal and inner continental shelf regions.展开更多
The Court finds that the process of decolonization of Mauritius was not lawfully completed when that country acceded to independence and that the United Kingdom is under an obligation to bring to an end its administra...The Court finds that the process of decolonization of Mauritius was not lawfully completed when that country acceded to independence and that the United Kingdom is under an obligation to bring to an end its administration of the Chagos Archipelago as rapidly as possible THE HAGUE, 25 February 2019.展开更多
In undertaking regular surveys on those waterbirds appearing on Fujian coast and on offshore islands,people of Xiamen Bird-watching Society had observed,for five times during 2007-2009,three marked individuals of the ...In undertaking regular surveys on those waterbirds appearing on Fujian coast and on offshore islands,people of Xiamen Bird-watching Society had observed,for five times during 2007-2009,three marked individuals of the Roseate Tern (Sterna dougallii) on Caiyu Archipelago of south Fujian offshore; it is now quite certain that the leg-flags were marked on birds by people of the Australasian Wader Studies Group (AWSG) and at least one of those leg-flagged terns is already over six or seven years old by the time of re-sighting; this record might be useful and helpful for further estimating the life circle as well as the length of generation of those gulls and terns appearing and breeding along the SE Chinese coast,such as the Black-tailed Gull (Larus crassirostris),the Great Crested Tern (Sterna bergii),the Chinese Crested Tern (S.bernsteini),etc.展开更多
文摘The East China Sea(ECS)off the Coast of Zhoushan Archipelago,Zhejiang(ECS-CZA)is home to abundant fishery resources and an important spawning,feeding,and nursing ground for a variety of fish species.Due to long-term overfishing,the ichthyoplankton structure has been dramatically altered.Understanding the species composition and distribution of fish eggs and larvae is one of the most essential tasks to accurately regulate fishery resources and formulate effective management policies;however,little is known about the ichthyoplankton in this region.In this study,an integrated strategy of morphology identification(MI)and mitochondrial COI DNA barcoding was used to identify species of fish eggs and larvae collected from the ECSCZA.MI revealed 15 fish egg species belonging to 12 families and 12 fish larva species belonging to 12 families;in contrast,DNA barcoding altogether identified 30 species,including 18 fish egg species and 13 fish larva species.One species was shared between the egg and larva samples.Our study offers useful tools and critical scientific information for further understanding the diversity,distribution,and conservation management of various ichthyoplankton species in the marine environment.
基金supported by the National Natural Science Foundation of China (32271734)。
文摘Nestedness is one of the important patterns in island biogeography,community ecology and conservation biology.However,most previous nestedness studies focus on the taxonomic dimension while neglecting the functional and phylogenetic processes in generating nestedness.Moreover,few studies have examined the seasonal change of the nestedness and underlying processes.Here,we examined the seasonal nestedness of bird assemblages in taxonomic,functional,and phylogenetic dimensions,and determined the underlying processes of nestedness patterns in the Zhoushan Archipelago,China.We surveyed the occurrence, abundance,and habitats of birds on 40 islands.We calculated taxonomic,functional,and phylogenetic nestedness using WNODF and treeNODF.We determined the processes underlying nestedness by relating nestedness ranks to island characteristics and species traits.The WNODF analyses showed that bird assemblages in winter and summer were both significantly nested.The habitat-by-site matrix was also significantly nested.The nestedness of bird assemblages was significantly correlated with island area,habitat diversity,habitat specificity,minimum area requirement,habitat specificity and hand-wing index(HWI) of birds in both seasons.While the distance to the nearest mainland(DTM) exerted the influence on nestedness in summer,the distance to the nearest larger island(DTNL)affected nestedness only in winter.However,the nestedness of bird assemblages was not caused by passive sampling or human disturbance.The results of treeNODF analyses illustrated that bird assemblages were functionally and phylogenetically nested in summer and winter,but the exact mechanisms were somewhat different in these two seasons.Overall,our results supported the habitat nestedness hypothesis,selective extinction hypothesis,and selective colonization hypothesis in both seasons.From a conservation viewpoint,we should protect islands with large area and diverse habitats,islands close to the mainland,and species with large area requirement and high habitat specificity to prevent local extinction.
基金The Scientific Research Fund of the Second Institute of Oceanography,Ministry of Natural Resources,China under contract Nos SZ2302 and JG2209.
文摘Macrobenthic organisms are commonly employed as biomonitors for environmental risk assessment.In this study,we aimed to investigate the spatial and temporal patterns of the macrobenthic community,which is influenced by environmental factors of sediments and bottom water layer.We sampled a total of 12,11,10,and 11 stations in the Shengsi Archipelago during June 2010,August 2010,November 2020,and April 2021 respectively.A total of 124 species of macrobenthos were identified,with polychaetes being the dominant group.The abundance,biomass,and diversity indices exhibited no significant temporal differences.Similarly,biodiversity did not exhibit a clear spatial gradient,likely due to the small study area and the absence of significant differences in key factors such as depth.However,the stations with the lowest biodiversity values consistently appeared in the southwest region,possibly due to the impact of human activities.Significant differences in the macrobenthic community were observed between all months except between June and August,and mollusk Endopleura lubrica and polychaete Sigambra hanaokai were important contributors to these differences according to the results of the Similarity Percentages analysis.Suspended particulate matter(SPM)was identified as the primary driving factors of macrobenthic variability.In summary,the community structure underwent temporal changes influenced by complex current patterns,while biodiversity remained relatively stable.This study contributes to our understanding of the key environmental factors affecting macrobenthic communities and biodiversity.It also provides valuable data support for the long-term monitoring of macrobenthos and the environment in the Shengsi Archipelago.
基金founded by National Natural Science Foundation of China (Grant Number:32370545)Marine Protected Area Administration of Sansha City (Monitoring seabird spatial-temporal dynamic project in Sansha City)Science and Technology Planning Projects of Guangdong Province, Grant Number:2021B1212110002
文摘Studying coexistence mechanisms is practically important for understanding and conserving marine biodiversity and community structure. Tropical marine ecosystems may exhibit higher competition between top predators due to generally low primary productivity and pronounced seasonal fluctuation in food availability. Consequentially, niche segregation in sympatric breeding seabirds is expected to occur as a mechanism to maintain species coexistence. However, a single-dimensional study on seabird niche segregation might result in unclear niche overlap. Here, we investigated multi-dimensional niche segregation of tropical seabirds during field expeditions to the Xisha Archipelago, China, in 2023. We reconfirmed the breeding status of six species of terns and noddy, and further revealed the multi-dimensional niche segregation among Black-naped (Sterna sumatrana), Bridled (Onychoprion anaethetus) and Roseate (Sterna dougallii) Terns. Spatially, these three species utilized nest sites that differentiated by vegetation and distance to sea. Temporally, Black-naped Terns bred earlier and for a longer period, while Bridled and Roseate Terns had more restricted breeding seasons. Furthermore, the daily foraging activity patterns of these species also differed, with Bridled Terns potentially having a longer foraging time at noon. In terms of diet, Bridled Terns were opportunists that fed on fishes, squids and insects, such as migratory fruit-piercing moths, while Roseate Terns were primarily piscivorous, especially feeding on Exocoetidae (flying fishes). Seabirds play a crucial role in marine ecosystems and are globally threatened. Our findings shed light on the complex mechanisms facilitating the coexistence of sympatric seabird species in China. Further research is needed to examine other ecological interactions and to develop effective conservation strategies for protecting these valuable seabird populations.
基金supported by the National Natural Science Foundation of China(31971545 and 32271734).
文摘Nested subset pattern(nestedness)is an important part of the theoretical framework of island biogeography and community ecology.However,most previous studies often used nestedness metrics or randomization algorithms that are vulnerable to type I error.In this study,we inves-tigated the nestedness of lizard assemblages on 37 islands in the Zhoushan Archipelago,China.We used the line-transect method to survey species occurrence,abundance,and habitat types of lizards on 37 islands during 2 breeding seasons in 2021 and 2022.We applied the nested metric WNODF and the conservative rc null model to control for type I error and quantify the significance of nestedness.Spearman rank cor relations were used to evaluate the role of 4 habitat variables(island area,2 isolation indices,and habitat diversity)and 4 ecological traits(body size,geographic range size,clutch size,and minimum area requirement)in generating nestedness.The results of WNODF analyses showed that lizard assemblages were significantly nested.The habitat-by-site matrix estimated by the program NODF was also significantly nested,support-ing the habitat nestedness hypothesis.The nestedness of lizard assemblages were significantly correlated with island area,habitat diversity.clutch size,and minimum area requirement.Overall,our results suggest that selective extinction and habitat nestedness were the main drivers of lizard nestedness in our system.In contrast,the nestedness of lizard assemblages was not due to passive sampling or selective colonization.To maximize the number of species preserved,our results indicate that we should protect both large islands with diverse habitats and species with largearea requirement and clutch size.
基金supported by the National Natural Science Foundation of China(32271734 and 31971545).
文摘Nestedness is an important part of the theoretical framework of island biogeography and community ecology.However,most previous studies focused on taxonomic dimension and overlooked functional and phylogenetic nestedness.Here,we simultaneously investigated taxonomic,functional,and phylogenetic nestedness of terrestrial mammals on 39 land-bridge islands in the Zhoushan Archipelago,China.As mammals’response to the environment may depend on their body size,we performed analyses for three mammal assemblages separately:overall species,large and medium-sized species,and small species.The taxonomic nestedness was quantified by organizing the species incidence matrix,while the functional and phylogenetic nestedness were estimated by combining the similarity of their ecological traits and phylogeny.Island characteristics(island area,three isolation indices,land use intensity,and habitat diversity)and species traits(body size,litter size,habitat specificity,geographic range size,and minimum area requirement)were used as predictors of nestedness.Overall and small species were significantly nested in 3 facets of nestedness,and results supported the selective extinction,selective colonization,and habitat nestedness hypotheses.Large and medium-sized species were functionally and phylogenetically nested when matrices were ordered by increasing distance to mainland,supporting the selective colonization hypothesis.Overall,differences in nestedness and its underlying mechanisms were detected not only in 3 facets of nestedness but also in the 3 mammal assemblages.Therefore,frameworks that incorporate taxonomic,phylogenetic,and functional nestedness can contribute to a more comprehensive understanding of nestedness processes.Additionally,it also improves our ability to understand the divergent responses of mammal assemblages to the insular environment.
文摘The archipelagic waters system is stipulated in the United Nations Convention on the Law of the Sea. It is closely related to China＇s marine legislation and maritime law enforcement. It is not only related to the integrity of our country＇s national sovereignty, but also to the maintenance of our maritime rights and interests. However, there is no comprehensive fundamental law governing the overall situation of marine development in our country, also no relevant legal code on the archipelagic waters system. Therefore, we should learn from the world＇s marine legislation and practice which the archipelagic waters system was written into China＇s marine legislation.
基金financially supported by the ongoing South China Sea deepwater project of Petrochinathe National Natural Science Foundation of China (Nos. 91228208, 41106064)+1 种基金the International Project of Science and Technology Bureau of Hainan Province (No. ZDYF2016215)the NSFC-Shandong Joint Fund for Marine Science Research Centers (No. U1606401)
文摘Fourteen isolated drowned reefs have been identified around the Xisha Uplift by multibeam and seismic data. The drowning processes of these reefs can be divided into three different stages, which correspond to three different accelerated tectonic subsidence periods. The drowning of the Xisha reefs is the result of the combined action of tectonic subsidence and sea level fluctuations, and the tectonic subsidence rate had to remain above 0.2 mm yr^(-1 )for a long time. Three abrupt accelerated tectonic subsidence events that occurred in the late Miocene, Pliocene and early Quaternary in the Xisha Uplift were closely related to the thermal subsidence processes after three stages of post-rifting magmatism. The magmatism of the middle Miocene and the following thermal subsidence resulted in the drowning of reefs in the northwestern Xisha uplift(Zone A). During the early Pliocene, massive magmatic intrusions and volcanic eruptions occurred in the Xisha Uplift. Then, the subsequent thermal subsidence started the drowning process of reefs in the northeastern and western regions of the Xisha Uplift(Zone B and C). During the early Quaternary, large-scale magmatism also occurred in the Xisha Uplift. The subsequent thermal subsidence resulted in a new rapid tectonic subsidence, which caused the reefs in the southern and southeastern regions of the Xisha Uplift to drown(Zone D and E).
基金Supported by Shandong 908 Project for Islands Investigationthe Knowledge Innovation Program of Chinese Academy of Sciences (No 072715)
文摘The community structure of intertidal macrobenthos in Changdao Archipelago(north of Shandong Peninsula,between Bohai Bay and the northern Yellow Sea) was examined based on samples collected from 14 stations in five transects in June 2007.Three stations corresponding to high,medium and low tidal areas were set up for each transect.A total of 68 macrobenthic species were found in the research region,most of which belonged to Mollusca and Crustacea.The average abundance and biomass of the macrobenthos was 1 383 ind./m2 and 372.41 g/m2,respectively.The use of an arbitrary similarity level of 20% resulted in identification of five groups among the 14 stations in the research region.There were remarkable differences in the biomass,abundance and Shannon-Wiener diversity index of the different sediments.Specifically,the order of biomass was rocky shores > gravel > mud-sand > coarse sand > stiff mud,while the order of abundance was rocky shores > coarse sand > mud-sand > gravel > stiff mud,and that of the diversity index was mud-sand > gravel > stiff mud > rocky shores > coarse sand.The above results revealed that the sediment type was the most important factor affecting the structure of the macrobenthic community of the intertidal zone.
文摘The transport mechanism and settlement characteristics of suspended sediments are analyzed in this article on the basis of measured data. Results indicate that the concentration and flux of suspended sediments decrease sharply from Hangzhou Bay to the offshore area. Suspended sediment transport is mainly controlled by advection transport and gravitational circulation transport. The settling velocity of suspended sediments gradually decreases from Hangzhou Bay to the offshore area. The settlement of suspended sediments mainly takes place during the turning phase of the tidal currents.
基金Supported by the National Key R&D Program of China(No.2018YFD0900806)the National Natural Science Foundation of China(No.U1806214)the landscape pattern analysis and remote sensing interpretation work were supported by the Shandong Ocean Special Fund“Ocean Health”Key Science and Technology Innovation Project(No.2018SDKJ05)。
文摘The modern landscape patterns of islands usually show obvious spatial heterogeneity and complex ecological effects due to the vulnerability of ecosystems with natural characteristics under increasing human activities.In this work,we studied the variation in landscape pattern of the Miaodao Archipelago in Bohai Sea,North China,from 1990 to 2019,and an evaluation index system was established to explore the impacts of natural conditions and human disturbances on the ecological effects in the pressure-state-response(PSR)framework.Empirical analysis was conducted on the natural conditions,human disturbances,and ecological effects.The results show that forest was the main component of the landscape pattern in the archipelago.Both of the areas offorest and construction land were increasing,and the areas of cropland and grassland were declining.Other landscape types changed slightly,and the landscape fragmentation was increasing.The natural condition exhibited positive effects while human disturbance showed negative effects on the local ecology.Human disturbances come mainly from shoreline use while the natural conditions were mainly from the elevation change.The ecological effects were resulted mainly from the net primary productivity and water yield.
基金The Special Project of Science and Technology Fundamental Work from the Ministry of Science and Technology of China under contract No.2012FY112500the National Natural Science Foundation of China under contract Nos 41206111 and 41206112
文摘To study the water quality influenced by the anthropogenic activities and its impact on the phytoplankton diversity in the surface waters of Miaodao Archipelago, the spatiotemporal variations in phytoplankton communities and the environmental properties of the surface waters surrounding the Five Southern Islands of Miaodao Archipelago were investigated, based on seasonal field survey conducted from November 2012 to August 2013. During the survey, a total of 109 phytoplankton species from 3 groups were identified in the southern waters of Miaodao Archipelago, of which 77 were diatoms, 29 were dinoflagellates, and 3 were chrysophytes. Species number was higher in winter（73）, moderate in autumn（70）, but lower in summer（31） and spring（27）. The species richness index in autumn（5.92） and winter（4.28） was higher than that in summer（2.83） and spring（1.41）.The Shannon-Wiener diversity index was high in autumn（2.82）, followed by winter（1.99） and summer（1.92）, and low in spring（0.07）. The species evenness index in autumn（0.46） and summer（0.39） was higher than that in winter（0.32） and spring（0.02）. On the basis of principal component analysis（PCA） and redundancy analysis（RDA）, we found that dissolved inorganic nitrogen（DIN） and chemical oxygen demand（COD） in spring, COD in summer, p H in autumn, and salinity and oil pollutant in winter, respectively, showed the strongest association with the distribution of phytoplankton diversity. The spatial heterogeneity of the southern waters of Miaodao Archipelago was quite obvious, and three zones, i.e., northeastern, southwestern and inter-island water area, were identified by cluster analysis（CA） based on key environmental variables.
基金The National Natural Science Foundation of China under contract No.41206174China Postdoctoral Science Foundation under contract No.2012M511546the Key Project of Chinese National Science Fundation under contract No.41330960
文摘Ground Penetrating Radar （GPR） measurements of sea ice thickness including undeformed ice and ridged ice were carried out in the central north Canadian Archipelago in spring 2010. Results have shown a significant spatial heterogeneity of sea ice thickness across the shelf. The undeformed multi-year fast ice of （2.05±0.09） m thick was investigated southern inshore zone of Borden island located at middle of the observational section, which was the observed maximum thickness in the field work. The less thick sea ice was sampled across a flaw lead with the thicknesses of （1.05±0.11） m for the pack ice and （1.24±0.13） m for the fast ice. At the northernmost spot of the section, the undeformed multi-year pack ice was （1.54±0.22） m thick with a ridged ice of 2.5 to 3 m, comparing to the multi-year fast ice with the thickness of （1.67±0.16） m at the southernmost station in the Prince Gustaf Adolf Sea.
基金The Special Project of Science and Technology Fundamental Work from the Ministry of Science and Technology of China under contract No.2012FY112500the National Natural Science Foundation of China under contract No.41206111
文摘Research on carrying capacity, aiming at maintaining the limited ability of the Earth＇s life supporting system to sustain human development, requires a comprehensive and ecosystem-based approach to monitor and assess the localized sustainability of coupled social and ecological systems. A definition termed the ecosystem-based carrying capacity of island（EBCCI） was developed in this paper of which the indices of fundamental and realized carrying capacities of island（FCCI and RCCI） were highlighted to emphasize the inter-dependencies between social systems and ecological systems. In order to avoid the difficulties and uncertainties of direct assessment, the related assessment model was established on the basis of synthetic evaluation of inherent and external factors affecting the EBCCI. The southern Miaodao Archipelago（SMA） located in the intersection of the Bohai Sea and the Yellow Sea, China, was taken as a typical example to acquire integrated recognition of the island ecosystem and its carrying capacity so as to discuss its sustainable development. The index scores of FCCI and RCCI in the SMA were 0.818 5 and 0.712 9 out of 1.0, respectively, with acceptable uncertainties. The results showed a relatively well capacity to sustain progress and relatively well realization of the carrying capacity of island ecosystem, owing to a well capacity of ecologically regulating, general performance of both ecologically supporting and resource provisioning, and a relatively high level of social supporting system. The study implied that it was critical to optimize the inter-dependencies and to sustain the relative balance between social systems and ecological systems so as to improve the RCCI and further facilitate the sustainability of SMA. The approach proposed in this paper provides a powerful tool which is well applicative to the regional level of an oceanic island or archipelago to study the sustainable development and can be further popularized to the coastal zone.
文摘Several significant events of a geological nature occurred approximately 800 ka before the present: (1) Australasian tektite fall (AA), (2) Brunhes-Matuyama geomagnetic reversal (BMR), (3) mid-Pleistocene changes in ice age cycles. Add to these the undated fault system (4) in the South-West (SW) of the South China Sea (SCS). Here we offer a unified cause for all four of these in (5), an impact in the SCS of a large, massive cosmic object, likely a comet, obliquely coming from the SW at an extremely shallow angle, striking the Sunda shelf yet unexploded with the shock of its compressed air bow wave, and causing the continual shelf and slope to collapse, resulting in the fault system (4), then traveling almost tangentially to the surface, exploding at impact with the sea surface, ejecting the tektites (1), creating the formation underlying the later atolls of Spratlies Archipelago (6), Nansha Islands in Chinese, & causing the BMR (2). An explanation of event (3) was Richard Muller’s hypothesis of planet Earth passing through an interplanetary dust cloud periodically due to ecliptic precession. Here we hypothesize this cloud actually is a belt of Australasian tektites ejected into space at super-orbital velocities that Earth encounters about every 100 ka.
文摘Based on the general and concrete principles of index system of marine economy and the choices of the evaluation index, this paper analyzes the index importance by means of AHP and establishes a set of the evaluation index system of marine economy in the Zhoushan Archipelago New District, to which an overall analysis and appraisal is given. The main factors that have limited the sustainable development of marine economy, in combination with the factors that influence its development, are put forward in accordance with its connotation of sustainable development of marine economy and sustainable development strategy based on marine tourism development.
基金National Natural Science Foundation of China,No.41530962,No.41625021The National Basic Research Program of China,No.2013CB956500Natural Science Foundation of Jiangsu Province,No.BK20130056
文摘Knowledge of the sediment flux derived from different sources is critical for interpreting the sedimentary records associated with large river sedimentary systems. For the Changjiang River system, previous studies hardly focused on the sediment load from the adjacent Zhoushan Archipelago(ZA). Based on four prediction models, aiming to improve the understanding of the sediment load from the ZA during the Holocene, we show that the predicted sediment flux of the ZA ranges from ~0.7 to 26.5 Mt·yr^(-1), with an average value of 10.7 Mt·yr^(-1), and the islands with a relatively large area or high relief contribute greatly to the total flux. This sediment load is an order of magnitude lower than that of the Changjiang River, but it is similar to those of the local small rivers. Located in the core area of the southward dispersal path of the Changjiang River plume, the ZA also influences the sediment transport into Hangzhou Bay and over the Zhejiang-Fujian coastal seas. On the Holocene temporal scale, e.g., for the period from 6 ka BP to 2 ka BP, the sediments discharged from the ZA had a considerable effect on the shelf sedimentary system. This study provides evidence for an important role an archipelago can play in terms of sediment supply and transport in coastal and inner continental shelf regions.
文摘The Court finds that the process of decolonization of Mauritius was not lawfully completed when that country acceded to independence and that the United Kingdom is under an obligation to bring to an end its administration of the Chagos Archipelago as rapidly as possible THE HAGUE, 25 February 2019.
文摘In undertaking regular surveys on those waterbirds appearing on Fujian coast and on offshore islands,people of Xiamen Bird-watching Society had observed,for five times during 2007-2009,three marked individuals of the Roseate Tern (Sterna dougallii) on Caiyu Archipelago of south Fujian offshore; it is now quite certain that the leg-flags were marked on birds by people of the Australasian Wader Studies Group (AWSG) and at least one of those leg-flagged terns is already over six or seven years old by the time of re-sighting; this record might be useful and helpful for further estimating the life circle as well as the length of generation of those gulls and terns appearing and breeding along the SE Chinese coast,such as the Black-tailed Gull (Larus crassirostris),the Great Crested Tern (Sterna bergii),the Chinese Crested Tern (S.bernsteini),etc.
