迁徙停歇期鸻鹬类在崇明东滩潮间带的食物分布

崇明东滩是鸻鹬类在东亚-澳大利西亚迁徙路线上重要的迁徙停歇地,滩涂上的底栖动物为迁徙的候鸟提供了丰富的食物来源。采用圆筒取样法对崇明东滩潮间带的大型底栖动物群落进行了研究。研究表明,该区域的大型底栖动物主要有腹足类、双壳类、甲壳类、多毛类环节动物及昆虫幼虫等类群。其中以腹足类密度最高（（2805±360）个/m^2）,约占底栖动物总密度的80%。其次为双壳类,密度为（320±31）个/m^2。双壳类的生物量（湿重）为（51.4±7.8）g/m^2,腹足类（38.7±5.1）g/m^2,两者占底栖动物总生物量的90%以上。不同类群的底栖动物在潮间带的空间分布上有显著差异。腹足类主要分布在海三棱藨草带,双壳类在海三棱藨草外带至光滩区域分布较多。从空间分布来看,腹足类在崇明东滩的北部区域分布较多,在南部区域则明显减少。双壳类在南北各条样线上的平均密度没有显著差异。除双壳类在秋季迁徙期的密度高于春季迁徙期外（P〈0.001）,其他类群的底栖动物在春季和秋季迁徙期的密度均无显著差异（P〉0.05）。     

Foraging strategies involved in habitat use of shorebirds at the intertidal area of Chongming Dongtan, China

Dense flocks of migratory shorebirds from diverse species often concentrate in the intertidal areas for stopover. Trophic structure, food partition, prey availability and selectivity, predation risk, and abiotic factors are often used to explain the differences in habitat use of coexisting shorebirds. We sampled the macrobenthos and surveyed the distribution of shorebird populations to study the effects of foraging strategies on the habitat use of shorebirds at Chongming Dongtan, an important stopover site for shorebirds on the East Asian–Australasian Flyway. Results show that the relative abundance of epifaunal macrobenthos in salt marshes was much higher than that in the bare flats, whereas the relative abundance of infaunal macrobenthos in salt marshes was much lower than that in bare flats. The relative abundance of two life forms of macrobenthos was similar in the transitional zones between the salt marshes and the bare flats. Shorebirds with different foraging strategies exhibited different habitat uses. Pause-travel shorebirds mainly utilized the salt-marsh fringes, while tactile continuous shorebirds relied heavily on the bare flats. There was no significant difference in habitat use for visual continuous shorebirds. The density of tactile continuous shorebirds was positively correlated with bivalve density, and that of visual continuous shorebirds positively with crustacean density. Meanwhile, the relative abundance of pause-travel foraging shorebirds was positively correlated with the relative abundance of epifaunal, but negatively with infaunal macrobenthos. In contrast, the relative abundance of tactile foraging shorebirds had a positive correlation with infaunal but a negative one with epifaunal life form. Therefore, foraging strategies may play important roles in shorebirds’ habitat use in intertidal areas.     

Carrying capacity for shorebirds during migratory seasons at the Jiuduansha Wetland, Yangtze River Estuary, China

The carrying capacity of food resources for migrating shorebirds was estimated at a stopover site in the Yangtze River Estuary during the two migratory sea-sons (spring and autumn). From March to May and September to November 2005, the macrobenthos resources of the Jiuduansha Wetland were investigated, and most of the macrobenthos species in the newly-formed shoal were found to be appropriate food for shorebirds. Biomass measurements showed that the total food resource was about 4541.20 kg AFDW (Ash-Free Dry Weight) in spring and about 2279.64 kg AFDW in autumn. Calculations were also done in the available habi-tats (intertidal bare mudflat and Scirpus x mariqueter/ Scirpus triqueter zones) for the shorebirds. The food resources in the available areas were about 3429.03 kg AFDW in spring and about 1700.92 kg AFDW in autumn. Based on the classification (by lean weight, basic metabolic rate and body length) of the shorebird community, and using the energy depletion model, it was theorized that all of the food resources in the Jiuduansha Wetland could support about 3.5 million shorebirds during spring season and 1.75 million shorebirds during autumn season. The shorebird carrying capacities in terms of the available food were about 2.6 million and 1.3 million birds during the two respective migration seasons. Considering the effect of intake rate, the potential carrying capacity was about 0.13-0.26 million shorebirds in the study area. The main factor restricting use of the area by shorebirds was the scarcity of available habitats for roosting at high tide rather than availability of food supply. We recommend restoring some wading pools in the dense Phragmites australis and Spartina alterniflora zones for shorebirds to roost in, to improve shorebirds' utilization efficiency of the resources in the Jiuduansha Wetland.     

长江口崇明东滩盐沼湿地围堤工程对底栖动物群落的影响

长江口崇明东滩盐沼湿地围堤工程是以清除入侵植物互花米草为目的而进行的生态修复工程。由于大型底栖动物可作为重要的环境指示生物,分析比较了围堤前后围堤工程内和工程外大型底栖动物群落结构及多样性的变化。结果表明,在2013年围堤工程前和2016年围堤工程后两次调查共采集到大型底栖动物29种,分别隶属于无针纲、多毛纲、腹足纲、双壳纲、甲壳纲和昆虫纲。在2013和2016年围堤外光滩生境分别采集到底栖动物21种和27种,并且所有样线都表现出物种数量增加或持平;然而在围堤内区域,两条全封闭样线(样线2和样线3)由围堤前的12种减少到围堤后的6种,而在保留进出水口的半封闭样线1围堤内由围堤前7种增加到围堤后12种。底栖动物平均密度在半封闭样线1围堤内由围堤前的(75±0)个/m^2增加到围堤后的(288±111)个/m^2(P=0.091),在全封闭的样线2(2013:(120±17)个/m^2;2016:(7±7)个/m^2)和样线3(2013:(359±20)个/m^2;2016:(93±93)个/m^2)围堤内都表现出围堤前显著高于围堤后(P<0.05);围堤外光滩区域所有样线虽然没有显著性差异,但是都表现出围堤后密度增加,总平均密度由围堤前的(410±83)个/m^2增加到2016年的(1184±393)个/m^2(P=0.072)。因此,在长江口盐沼湿地进行互花米草生态治理的围堤工程,保留进出水口保持围堤区域与外界自然水域的连通性对围堤内底栖动物结构及多样性有积极作用,而围堤外底栖动物结构及多样性在所有样点均处上升趋势。围堤工程主要对软体动物和多毛类影响较大,而同时这些物种还是鸟类或者鱼类的重要食物资源,从而对鸟类和鱼类等次级消费者造成影响。从底栖动物群落变化及其生境来看,建议应该采取保留进出水口的围堤方式,维持潮水的出入,恢复围堤内与围堤外的生境连通性。     

长江口潮间带底栖生物生态及变化趋势

基于长江口3个区域潮间带(崇明东滩、南汇边滩和嵊山岛)监测数据,对长江口区域潮间带底栖生物生态现状及变化趋势进行评价。结果表明,2019年长江口海域泥相和岩相潮间带共鉴定大型底栖生物9门57种,软体动物、甲壳类和多毛类构成主要类群。崇明东滩、南汇边滩两个泥相潮间带底栖生物平均栖息密度分别为96.4个/m~2和160.4个/m~2,平均生物量分别为68.42 g/m~2和45.71 g/m~2;嵊山岛岩相潮间带平均栖息密度和生物量分别为488.9个/m~2和763.72 g/m~2。各断面多样性、丰富度和均匀度指数分别位于1.36—3.24、0.75—2.88和0.48—0.77,泥相潮间带低潮区生物多样性优于中潮区和高潮区,岩相潮间带中潮区生物多样性最好。聚类分析可见长江口海域潮间带底栖生物分为泥相和岩相2个大组群,物种分布存在明显的分潮区现象,高潮区站位成群或与个别中潮区站位成群,低潮区站位成群或与个别中潮区站位成群,表明底质类型和潮汐是影响潮间带大型底栖生物群落结构的主要因子。近30年来,崇明东滩和南汇边滩底栖生物种类数存在一定波动,嵊山后陀湾断面生物种类数明显下降;3个区域潮间带...     

Wind conditions affect stopover decisions and fuel stores of shorebirds migrating through the south Yellow Sea

We assessed the effects of wind conditions on stopover decisions and fuel stores of migratory shorebirds at Chongming Dongtan in the south Yellow Sea along the East Asian–Australasian Flyway. In spring and autumn, wind directions differed among altitudes and wind speed generally increased with altitude. Numbers of shorebirds were related to wind effects at low altitudes (on the ground and at 300 and 800 m above the ground), wind effects at 300 m being the best predictor of shorebird numbers. In spring, total number of shorebirds and numbers of the four most abundant shorebird species were negatively related to wind assistance at low altitudes, more birds departing when tailwinds prevailed and more arriving when headwinds prevailed. In autumn, however, total number of shorebirds and numbers of the four most abundant species were positively related to wind assistance at low altitudes, more birds departing and more arriving with tailwinds than with headwinds. When tailwinds prevailed, the number of arriving birds was higher than the number of departing birds. The fuel stores of captured shorebirds, represented by their body mass, was related to wind effects and change in wind conditions between two consecutive days in both spring and autumn, captured birds being heavier when headwinds prevailed than in tailwind conditions, and when the wind conditions became less favourable for flight between two consecutive days. Our results suggest that wind conditions affect stopover decisions and fuel stores, and thus the optimal migration and fuel deposition strategies of migratory shorebirds.     

长江口新生湿地大型底栖动物群落时空变化格局

为了解长江口新生湿地大型底栖动物时空变化格局,2004年11月—2005年10月对九段沙湿地的3个沙洲以及各主要生境进行了调查。结果表明:九段沙湿地大型底栖动物密度和生物量均呈春季最高,夏、秋季下降,秋季末和冬季回升的趋势,整体生物多样性水平较低,分布不均匀。夏季上沙和中沙底栖动物密度存在显著差异,四季生物密度和生物量空间梯度为下沙>上沙>中沙。由物种组成分析可知,九段沙湿地大型底栖动物群落时空变化与优势种的消长有关。各季海三棱藨草带和藨草带底栖动物密度和生物量最高,芦苇和互花米草次之,光滩区域最低,且群落季节波动大。外来物种互花米草生境下底栖动物群落特征与土著种芦苇生境下无显著差异。     

崇明东滩鸻鹬类迁徙路线的环志分析

崇明东滩为东亚-澳大利西亚鸻鹬类迁徙路线上的重要迁徙停歇地.本文通过分析崇明东滩回收的异地环志鸻鹬类记录及异地回收的崇明东滩环志的鸻鹬类记录,研究崇明东滩鸻鹬类的迁徙路线.1979～2008年间,崇明东滩共回收到来自澳大利亚西北部、澳大利亚维多利亚、美国阿拉斯加及新西兰北岛等17个国家与地区环志的鸻鹬类265只,包括大滨鹬(Calidris tenuirostris)、斑尾塍鹬(Limosa lapponica)、红腹滨鹬(C.canutus)等16种鸟类,其中春季北迁期间的记录占总数的93%;2003～2008年间,澳大利亚西北部、新西兰南岛、中国大陆及新西兰北岛等10个国家与地区回收到崇明东滩环志的大滨鹬、斑尾塍鹬、红腹滨鹬等12种鸟类,共计164只.在所有与崇明东滩鸻鹬类存在迁徙连接的20个国家和地区中,澳大利亚西北部的回收记录占全部回收记录的55%.根据斑尾塍鹬和红腹滨鹬不同亚种的越冬地分布,崇明东滩回收的斑尾塍鹬有L.l.menzbieri与L.l.baueri两个亚种,红腹滨鹬有C.a.piersmai和C.a.rogersi两个亚种.     

Carrying capacity for shorebirds during migratory seasons at the Jiuduansha Wetland, Yangtze River Estuary, China

The carrying capacity of food resources for migrating shorebirds was estimated at a stopover site in the Yangtze River Estuary during the two migratory seasons (spring and autumn). From March to May and September to November 2005, the macrobenthos resources of the Jiuduansha Wetland were investigated, and most of the macrobenthos species in the newly-formed shoal were found to be appropriate food for shorebirds. Biomass measurements showed that the total food resource was about 4541.20 kg AFDW (Ash-Free Dry Weight) in spring and about 2279.64 kg AFDW in autumn. Calculations were also done in the available habitats (intertidal bare mudflat and Scirpus × mariqueter/Scirpus triqueter zones) for the shorebirds. The food resources in the available areas were about 3429.03 kg AFDW in spring and about 1700.92 kg AFDW in autumn. Based on the classification (by lean weight, basic metabolic rate and body length) of the shorebird community, and using the energy depletion model, it was theorized that all of the food resources in the Jiuduansha Wetland could support about 3.5 million shorebirds during spring season and 1.75 million shorebirds during autumn season. The shorebird carrying capacities in terms of the available food were about 2.6 million and 1.3 million birds during the two respective migration seasons. Considering the effect of intake rate, the potential carrying capacity was about 0.13–0.26 million shorebirds in the study area. The main factor restricting use of the area by shorebirds was the scarcity of available habitats for roosting at high tide rather than availability of food supply. We recommend restoring some wading pools in the dense Phragmites australis and Spartina alterniflora zones for shorebirds to roost in, to improve shorebirds’ utilization efficiency of the resources in the Jiuduansha Wetland. __________ Translated from Acta Ecologica Sinica, 2007, 27 (1): 90–96 [译自:生态学报]     

上海市潮滩湿地大型底栖动物的空间分布格局

通过对上海市6个典型潮滩湿地（崇明东滩、崇明北滩、九段沙、青草沙、南汇边滩和杭州湾北岸）的调查,共记录到大型底栖动物112种,甲壳动物、软体动物和环节动物分别占总物种数的51．8％、22．3％和18．8％。6个潮滩湿地中大型底栖动物生物量的空间分布呈现一致的规律,即高潮区〉中潮区〉低潮区;在生物量构成中,甲壳动物是最为重要的类群,其总体平均相对贡献率在51％～97％之间,软体动物的总体平均相对贡献率在2％～48％之间。大型底栖动物密度的空间分布在地点间存在较大差异,在崇明东滩、九段沙和杭州湾北岸湿地中,软体动物在数量上占优势;而在崇明北滩、青草沙和南汇边滩,甲壳动物却是优势类群。与20世纪80和90年代的调查资料相比,近20多年来上海市潮滩湿地中大型底栖动物生物量明显增加,但群落结构发生了根本改变,优势类群由个体较小的软体动物转变为平均体重较大的甲壳动物,这主要与人类活动（过度采捕、环境污染和生物促淤等因素）的强度干扰有关,也反映上海市潮滩湿地的环境质量和生态功能正在逐步下降。     

长江口九段沙湿地大型底栖动物群落结构的季节变化规律

2004年11月至2005年10月,调查了长江口九段沙湿地大型底栖动物群落特征的季节变化及其土壤因子影响,共调查到大型底栖动物30种,主要由甲壳动物、环节动物、软体动物及昆虫幼体组成,光滑狭口螺(Stenothyra glabra)、堇拟沼螺(Assiminea violacea)、焦河蓝蛤 (Potamocorbula ustulata)、中国绿螂 (Glaucomya chinensis)和谭氏泥蟹(Ilyrplax deschampsi)为优势种,且生物密度四季变化明显.春季大型底栖动物生物密度和生物量处于最高水平,多样性指数最高.夏季密度和生物量最低,物种多样性也较低,分布较不均匀.秋、冬季生物种类数与生物量差异不显著,生物密度冬季较秋季高.春、夏、秋季底栖动物种类数、密度和生物量均未与土壤因子达到显著相关水平.冬季土壤湿度与有机质含量与底栖动物密度显著相关.     

放牧对滩涂底栖动物的影响

于2005年5月（春季）和10月（秋季）,调查了放牧对上海市崇明东滩大型底栖动物的影响.调查采样设置3个样区,其中Ⅰ、Ⅱ样区在放牧区,Ⅲ样区在非放牧区,3个样区均在潮间带的中潮带,共计90个样方.采集到底栖动物13种,其中节肢动物7种,软体动物4种,环节动物2种.Ⅰ、Ⅱ和Ⅲ样区春季分别有6、8和10种,秋季6、8和12种.各样区秋季底栖动物的平均密度均高于春季,春、秋季各样区的平均密度又均以Ⅲ样区最高.生物量与密度变化大体相似,以Ⅲ样区最高.与Ⅰ、Ⅱ样区相比,Ⅲ样区的多样性指数、均匀度和丰富度均最高,说明放牧改变了底栖动物种类分布的格局,使底栖动物的密度、生物量均有不同程度的改变,且放牧对崇明东滩底栖动物的生物多样性产生了一定的负面影响.     

鸭绿江口湿地鸻鹬类停歇地的生物生态研究

鸭绿江口湿地是鸻鹬类在东亚一澳大利亚北迁路线上的最重要停歇地,潮间带上的双壳类、腹足类、多毛类等底栖动物为鸻鹬类提供了能量保障.2010年3月-2011年6月对鸭绿江口潮间带的生物生态进行了调查研究.研究结果表明,生物群落结构相对简单,主要以双壳类、腹足类和多毛类为主,优势种演替明显,系统具有低多样性低密度的特点.鸻鹬类能量补充来源相对匮乏,饵料生物量的更新速度较慢,所提供的能值也相对较低,江户明樱蛤、青蛤(幼体)和长吻沙蚕是鸻鹬类的主要食物来源.鸻鹬类主要集中在低潮带下区觅食,在北迁高峰期对低潮带下区饵料生物影响较显著,尤其对江户明樱蛤丰度影响最明显.泥螺作为优势种,生态位最宽,分布于整个调查断面和潮带,但因体表分泌一种毒性粘液而不被鸻鹬类取食.饵料生物的种群补充能力较强,在鸻鹬类迁徙高峰期之后,饵料丰度和生物量又会恢复到正常水平.虽然目前人类对鸻鹬类的威胁显现较小,但使人类一生态系统一滨鸟之间持续和谐统一,必须综合考量鸭绿江口湿地包括人类在内的生态系统各关键组分之间的生态关联,兼顾生态系统的完整性和人类社会经济发展的可持续性.     

洋山港潮间带大型底栖动物群落结构及多样性

2009-2010年在洋山港海域大洋山岛和圣姑礁进行四个季度潮间带大型底栖动物生态学研究。共采集到大型底栖动物61种,以广布种为主,部分为河口低盐种,其中软体动物22种,环节动物16种,节肢动物12种,苔藓动物5种,腔肠动物4种,星虫动物和棘皮动物各1种。优势种为短滨螺(Littorina brevicula)、多齿围沙蚕(Perinereis nuntia)、日本笠藤壶(Tetraclita japonica)、齿纹蜒螺(Nerita yoldii)和特异大权蟹(Macromedaeus distinguendus)。丰度和生物量在不同季节明显不同(P<0.05):丰度的最高值出现在春季,为(3204.9±837.84)个/m²,最低值出现在秋季,仅为(2213.2±731.27)个/m²;生物量的最高值则出现在夏季(2233.2±1493.42)g/m²,冬季最少,仅为(819.95±484.80) g/m²。大洋山岛和圣姑礁的丰度和生物量具有较大差异(P<0.05):年均丰度以大洋山断面较高,为(3090±742.74)个/m²,圣姑礁断面较低,为(2133±372.51)个/m²;而年均生物量则以圣姑礁断面较高,为(1711.1±1180.76) g/m²,大洋山断面较低,仅为(1028.5±627.61) g/m²。运用ABC曲线、等级聚类和MDS对大型底栖动物群落结构分析发现:大洋山潮带间大型底栖动物群落尚未受到干扰或干扰较轻,群落结构相对稳定;而圣姑礁断面的潮间带大型底栖动物群落受到了中度的干扰,群落结构稳定性下降。与15年前的研究相比,圣姑礁大型底栖动物的密度和生物量均有大幅度的降低,这与洋山港海域盐度的升高、生态环境变化和人为干扰强度增加等有关。     

Bio-energetic data show weak spatial but strong seasonal differences in wetland quality for waders in a Mediterranean migration bottleneck

1. Assessing the quality of wetlands as refuelling areas for migrating waterbirds based on resource distribution patterns is challenging. Resources in wetlands can vary both horizontally and vertically and may be differentially available to different bird species at different times of the year. Therefore, the extent to which wetland quality can be generalised across seasons and for a diversity of birds remains unresolved.
2. Spatiotemporal variation in abundance and quality of macrobenthos as food for migrating waders was studied in a set of wetland areas near a Mediterranean migration bottleneck in the Balkan peninsula, during both spring and autumn migration. Samples were subdivided into different depth layers to differentiate between parts of the sediment that are accessible to different groups of wader species. To quantify food availability and the resulting refuelling capacity in different wetland habitat types, abundance, wet weight, and lipid and protein content of invertebrate taxa were determined for each sample.
3. Invertebrate food availability and quality were markedly higher in spring than in autumn. Given the higher abundance and protein and lipid content of prey in spring, the total energy that could be harvested in spring (3.81 ± 0.79 kJ/m²) was about 7 times higher than in autumn (0.56 ± 0.12 kJ/m²). Most prey were found in the top layer of the sediment (0–22 mm depth), but about a third of the total energy was present in the deepest soil layer that only longer-billed species could reach (55–200 mm depth). Higher quality prey items such as larger-bodied and heavier polychaetes and bivalves were found in the deeper sediment layers.
4. For other taxa, there was no evident vertical pattern of increasing individual body size. Prey abundance differed between certain habitat types but, overall, food availability could not be linked to distinct habitats. In spring, redox potential tended to be higher, while pH, vegetation cover, conductivity, and temperature were lower than in autumn.
5. Different wetland habitat classes used in a conservation framework may provide similar food resources for waders. As a result, linking food availability to habitat classifications is not straightforward. Furthermore, seasonal variation in wetland quality requires a re-evaluation of the importance of wetland areas during spring and autumn migration. Finally, nutritional analyses are essential for determining the capacity of wetlands to support refuelling by migratory waterbirds.

     

上海崇明东滩震旦鸦雀冬季种群栖息地的生境选择

2008年11月-2009年3月,在崇明东滩对震旦鸦雀(Paradoxornis heudei)种群生态进行调查研究,并对震旦鸦雀种群和生境因子的相关性进行分析。运用单因素方差对互花米草(Spartina alterniflora)入侵和芦苇(Phragmites australis)收割造成的芦苇滩涂变化进行分析,并运用多元回归的方法对震旦鸦雀种群的密度和分布以及相关环境因子进行生境选择分析。结果表明,崇明东滩震旦鸦雀种群的密度为(5.08±3.11)只/hm2;震旦鸦雀种群的密度和芦苇直径呈极显著正相关,震旦鸦雀种群的分布和芦苇的高度、密度呈极显著正相关,和食物资源量呈显著正相关;互花米草和震旦鸦雀种群的密度和分布呈显著负相关;互花米草入侵和芦苇收割降低了震旦鸦雀越冬期的栖息地质量,保留一部分生长质量较好的芦苇可以缓解震旦鸦雀冬季种群的生存压力。     

Age structure and age‐related differences in molt status and fuel deposition of Dunlins during the nonbreeding season at Chongming Dongtan in east China

ABSTRACT Although most shorebirds exhibit deferred migration and deferred breeding during their first summer, Dunlins (Calidris alpina) migrate to breeding areas and breed during their first summer. First‐year and adult Dunlins should, therefore, have similar fueling and molt patterns if energetic and physiological constraints are responsible for deferred migration. From 2006 to 2008, we examined the age structure of Dunlins during the nonbreeding season at Chongming Dongtan, an estuarine wetland in the Yangtze River estuary in east China, and examined the effects of date, age, and molt status on fuel deposition during migration and during the winter. The Dunlin population at Chongming Dongtan was composed primarily of first‐year birds. Most adults and first‐year birds arrived together in late August. Regression analyses indicated that age, date, and molt status affected fuel deposition (as indicated by body mass) of Dunlins. Adults had significantly greater fuel deposits than first‐year Dunlins near the end of northward migration (May: adults 70.8 ± 6.4 g, first‐year 63.8 ± 8.0 g) and at the start of southward migration (September: adults 50.2 ± 6.1 g, first‐year 47.2 ± 4.9 g). Adults also had significantly higher fuel deposition rates than first‐year Dunlins during northward migration. Nonetheless, first‐year Dunlins migrate and breed in their first summer. Thus, other factors, such as migration distance and body size, may be more important in determining if first‐year shorebirds defer migration during their first spring and summer. During boreal spring and autumn, first‐year Dunlins in active body molt had greater body mass than those that had not initiated body molt or those in suspended molt, and premigratory fuel deposits for northward migration were greatest after prealternate molt was completed. These results suggest that body molt requires additional fuel deposits and imposes a constraint on fuel deposition for migratory flights.     

基于空间分带的崇明东滩水鸟适宜生境的时空动态分析

本文采用1990—2008年期间6期Landsat TM遥感影像的解译结果,基于ArcGIS空间分带方法并构建生境有利度指数,分析了崇明东滩水鸟适宜生境的时空动态。结果表明：（1）近20 a来,主要受自然湿地的围垦、堤内土地利用方式变化和堤外互花米草(Spartina alterniflora)入侵的影响,崇明东滩海三棱藨草(Scirpus mariqueter)群落（SMC）和养殖塘（AP）的数量特征变化较大,水鸟适宜生境的数量和结构经历了由自然生境到人工生境再到自然生境占支配地位的变化;（2）1990—2008年期间,SMC和AP生境有利度指数值的最高年份分别是1990和2003年,指数值的最低年份分别是2000和2008年;（3）1990s年代的大规模围垦以及互花米草的入侵,致使SMC生境的面积锐减,其主要分布范围从1990年的堤外1000—5000 m变为堤外0—3000 m处,导致SMC生境状况恶化;（4）大堤内AP生境是崇明东滩的重要水鸟生境类型,受堤内土地利用方式改变的影响,该生境2008年的生境有利度指数很低。崇明东滩鸟类生境的管理和保护不仅应重视自然湿地中的光滩与浅水区域,同时更应侧重于海三棱藨草群落和堤内养殖塘的管理和保护,其重点管理和保护范围可界定在堤外3000 m到堤内2000 m之间。崇明东滩水鸟生境的管理应实现多目标管理,维持各类适宜生境的足够面积和合理的空间布局,并在时间尺度上保持相对稳定,才能有效地保护各类水鸟种群及其生物多样性。     

长江口九段沙湿地不同生境中大型底栖动物群落结构特征分析

2004年10月至2005年1月对九段沙湿地大型底栖动物的群落分布特征及环境因子进行了调查。选取6种主要生境的57个样方,分析大型底栖动物的种类、密度、生物量、多样性指数及均匀度指数等群落特征。共记录到28种大型底栖动物,主要由甲壳动物、环节动物、软体动物及昆虫幼体组成,优势种为谭氏泥蟹(Ilyrplaxdeschampsi)、光滑狭口螺(Stenothyraglabra)、堇拟沼螺(Assimineaviolacea)、绯拟沼螺(A.latericea)和霍甫水丝蚓(Limnodriuhoffmeisteri)。6种生境类型中以低潮位光滩大型底栖动物种类最为丰富,但其密度最低;海三棱藨草(Scirpusmariqueter)带底栖动物密度最高,并且其均匀度与其他生境存在显著差异;互花米草(Spartinaalterniflora)带下底栖动物的种类组成与其他生境有一定差异,但种类数、密度和多样性处于平均水平,总体群落结构没有显著差异。     

A place to land: spatiotemporal drivers of stopover habitat use by migrating birds

Migrating birds require en route habitats to rest and refuel. Yet, habitat use has never been integrated with passage to understand the factors that determine where and when birds stopover during spring and autumn migration. Here, we introduce the stopover‐to‐passage ratio (SPR), the percentage of passage migrants that stop in an area, and use 8 years of data from 12 weather surveillance radars to estimate over 50% SPR during spring and autumn through the Gulf of Mexico and Atlantic coasts of the south‐eastern US, the most prominent corridor for North America’s migratory birds. During stopovers, birds concentrated close to the coast during spring and inland in forested landscapes during autumn, suggesting seasonal differences in habitat function and highlighting the vital role of stopover habitats in sustaining migratory communities. Beyond advancing understanding of migration ecology, SPR will facilitate conservation through identification of sites that are disproportionally selected for stopover by migrating birds.