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111.
Escalating pressures caused by the combined effects of population growth, demographic shifts, economic development and global climate change pose unprecedented threats to sandy beach ecosystems worldwide. Conservation of beaches as functional ecosystems and protection of their unique biodiversity requires management interventions that not only mitigate threats to physical properties of sandy shores, but also include ecological dimensions. Yet, beach management remains overwhelmingly focused on engineering interventions. Here we summarise the key outcomes of several workshops, held during the 2006 Sandy Beach Ecology Symposium in Vigo, Spain, that addressed issues of climate change, beach management and sampling methodology. Because efficient communication between managers and ecologists is critical, we summarise the salient features of sandy beaches as functional ecosystems in 50 'key statements'; these provide a succinct synopsis of the main structural and functional characteristics of these highly dynamic systems. Key outcomes of the workshops include a set of recommendations on designs and methods for sampling the benthic infaunal communities of beaches, the identification of the main ecological effects caused by direct and indirect human interventions, the predicted consequence of climate change for beach ecosystems, and priority areas for future research.  相似文献   
112.
长江口邻近海域大型底栖生物群落结构分析   总被引:10,自引:0,他引:10  
2004年5月的调查共获大型底栖生物50种,种数和丰度的优势生物为多毛类动物,而底栖鱼类和螠虫的生物量占明显优势。长江口大型底栖生物平均生物量为17.57g/m2,平均丰度为150ind./m2。生物量和丰度密集区集中在盐度25度线附近海域。根据Bray-Curtis相似性系数聚类分析和多维排序尺度分析,长江口大型底栖生物可划分为四个群落:Ⅰ圆筒原盒螺-滩栖阳遂足-棘刺锚参-背蚓虫群落;Ⅱ圆筒原盒螺-钩虾群落;Ⅲ背蚓虫-奇异稚齿虫-不倒翁-尖叶长手沙蚕-近辐蛇尾群落;Ⅳ短叶索沙蚕-长吻沙蚕-纽虫群落。通过引入环境变量的二维MDS图分析,长江口大型底栖生物群落分布与底层盐度、有机物具有较大的相关性。生存环境短时间内的剧烈变化是导致群落Ⅱ和Ⅳ种群贫乏的重要原因之一。河口区悬浮粉砂颗粒的短期快速沉降现象可能也是导致群落Ⅱ和Ⅳ种群贫乏的另一重要原因。  相似文献   
113.
根据2016年5月和11月在日照潮下带海域进行的调查资料,分析了该海域大型底栖动物的群落结构特征,探讨了其与环境因子的关系。研究海域共鉴定大型底栖动物60种,其中环节动物门30种,节肢动物门16种,软体动物门8种,其他类群6种。春季优势种为巴氏钩毛虫(Sigambra bassi)、扇栉虫(Amphicteis gunneri)、小头虫(Capitella capitata)和醒目云母蛤(Yoldia notabilis);秋季优势种为绒螯近方蟹(Hemigrapsus penscillatus)、索沙蚕科(Lumbrineriiae)1种、哈氏美人虾(Callanssa harmandi)和长鳃树蛰虫(Pista branchia)。春、秋两季平均密度依次为96.83、112.63 ind./m2;平均生物量依次为6.21、14.75 g/m2;平均种类多样性指数依次为1.45、1.66;平均丰度指数依次为0.40、0.44。综合聚类分析和丰度/生物量曲线(ABC曲线)分析表明研究区域大型底栖动物春、秋两季均可划分为4个群落,且群落结构均已受到严重扰动。BIOENV分析表明影响群落结构的主要环境因子为水温、溶解氧、亚硝酸盐、油类和重金属砷;Pearson 相关分析表明影响生物量和密度的主要环境因子为水深、水温、pH、化学需氧量和重金属铜。受人类活动的影响,和历史调查资料相比,研究区域大型底栖动物总物种数目、平均生物量均呈下降趋势。  相似文献   
114.
为了解舟山附近海域大型底栖动物群落组成特点及其与环境因子的内在关联,在2019~2020年对舟山附近海域12个站位的大型底栖动物及环境因子进行了调查研究。采用丰度、生物量、相对重要性指数(IRI)、Cluster聚类以及PCoA分析和Pearson相关性分析等方法对该海域的大型底栖动物群落组成、主要影响环境因子进行了分析。结果表明,两个航次共在舟山海域采集到大型底栖动物56种,其中多毛类动物28种,甲壳动物8种,软体动物7种,棘皮动物6种,刺胞动物3种、纽形动物2种,星虫动物和脊索动物各1种;两年平均丰度和生物量分别为36.32ind./m2和5.59g/m2,纽虫(Nemertea)是丰度的最大贡献者,而星虫爱氏海葵(Edwardsia sipunculoides)和棘刺锚参(Protankyra bidentata)则是生物量的最大贡献者;2020年大型底栖动物的总物种数、丰富度指数和多样性指数高于2019年,且两年舟山海域大型底栖动物的总物种数、丰富度指数和多样性指数均高于舟山邻近海域。与舟山海域大型底栖动物群落最相关的环境因子是水深、底层水盐度和硝态氮(NO3),这三个环境因子彼此相关性显著,随着盐度的增加,水深逐渐增加而硝酸氮含量则显著降低,群落物种数、丰度和丰富度则显著增加。通过对舟山附近海域大型底栖动物群落组成特点及其与环境因子的内在关联的研究,有望为东海近岸海域大型底栖动物群落的演替规律研究提供基础数据和科学依据。  相似文献   
115.
To understand the characteristics of macrobenthic structures and the relationship between environment and benthic assemblages in jellyfish bloom, we studied the macrobenthos and related environmental factors in the coastal waters of the Yellow Sea and East China Sea. Data were collected during two seasonal cruises in April and August of 2011, and analyzed with multivariate statistical methods. Up to 306 macrobenthic species were registered from the research areas, including 115 species of Polychaeta, 78 of Crustacea, 61 of Mollusca, 30 of Echinodermata, and 22 of other groups. Nine polychaete species occurred at frequencies higher than 25% from the sampling stations: Lumbrineris longifolia, Notomastus latericeus, Nin6e palmata, Ophelina acuminata, Nephtys oligobranchia, Onuphis geophiliformis, Glycera chirori, Terebellides stroemii, and Aricidea fragilis. Both the average biomass and abundance of macrobenthos are higher in August (23.8 g/m^2 and 237.7 ind./m^2) than those in April (11.3 g/m^2 and 128 ind./m^2); the dissimilarity ofmacrobenthic structures among stations is as high as 70%. In terms of the dissimilarity values, we divided the stations into four clusters in spring and eight in summer. The ABC curve shows that the macrofauna communities in high jellyfish abundance were not changed. Canonical correspondence analysis showed that depth, temperature, median grain size, total organic carbon of sediment and total nitrogen in sediment were important factors affecting the macrozoobenthic community in the study area.  相似文献   
116.
The macrobenthic production of an estuarine system was evaluated over a 14-year study period in a seagrass bed and in a sandflat. Over this period, the estuary suffered severe eutrophication and extreme weather events with important impacts on the community, impairing system functioning and ultimately the goods and services provided by the estuary (decline in the seagrass bed, decreased community production and/or a boost in the production by opportunist species, such as Hydrobia ulvae). Following the anthropogenic impacts, management measures were introduced which allowed a gradual recovery of the seagrass bed and a new macrobenthic community structure manifested by production increases of slow-growing species, such as Scrobicularia plana and Hediste diversicolor. There was a gradual re-orientation of energy into population biomass instead of population density but this was not translated into higher community production, mainly due to the decreased production of opportunist species (H. ulvae and several polychaetes). Several weather extreme events occurred during this post-mitigation phase - floods, heatwaves and droughts, all of which had negative impacts on macrobenthic dynamics and production. The heatwaves led to the greatest decreases in macrobenthic production, mainly due to S. plana perhaps associated with its physiological intolerance of higher temperatures. The prolonged drought that followed the heatwaves maintained low levels of production by S. plana and H. ulvae. With climate change, the frequency and intensity of extreme weather events are likely to increase worldwide so that the recovery of impacted/disturbed systems from impacts such as eutrophication may be seriously affected by these additional stressors, compromising attempts to improve the ecological quality of estuarine ecosystems.  相似文献   
117.
118.
In early summer plaice (Pleuronectes platessa L.) in the Clyde Sea Area eat Tellina siphons and spionid palps. As they grow, they take progressively larger siphons, fragments of spionids and some crustaceans. In late summer they eat entire spionids and other sedentary polychaetes. There is no significant predation on fish. The common dab [Limanda limanda (L.)] took a wider range of prey species than the plaice, but also depended mainly on polychaetes, crustaceans and bivalves. Depth distribution may limit both intra- and interspecific competition between these fish and also influence the choice of prey. The results from the main nursery areas of Irvine and Ayr Bays were similar to those from the other bays throughout the Clyde Sea Area and support earlier work at Firemore Bay in north-west Scotland and in the Dutch Wadden Sea.The growth rate of the fish increases during the early summer and may be related to increasing food availability, feeding experience of the fish and longer day length. Growth rate between areas appeared to be correlated with benthic productivity. 0-group plaice in Irvine, Ayr and Firemore Bays grew to different mean lengths by the end of the summer growth season, being 82 mm, 73 mm and 61 mm, respectively, for the period 1972–1974. This agrees with the known differences in standing stocks of intertidal macrobenthos in these bays (17·0, 11·1 and 1·3 g m?2 dry weight, respectively). The significance of this in relation to survival is discussed. Offshore migration of the larger fish in the autumn may result in apparent slowing of growth rates prematurely in inshore areas. The year-class strength depends more on the food availability in the nursery areas than on the number of plaice that settle on the bottom.  相似文献   
119.
石岛海域大型底栖生物群落特征   总被引:2,自引:0,他引:2  
2008年8月~2009年5月分4个航次对石岛海域进行大型底栖生物调查,共发现大型底栖生物164种,整个调查海域内大型底栖生物的优势种明显;调查海域大型底栖生物平均密度和平均生物量分别为279个/m2和11.00 g/m2;调查海域大型底栖生物初步分为近岸的粗砂底质群落和离岸较远的泥沙底质群落。本调查结果与其他海域调查资料做了对比,并初步分析了与其他调查海域结果不同的原因。  相似文献   
120.
为揭示现阶段浙江檀头山岛周围海域大型底栖动物群落现状,于2013年7月、2013年11月对该海域进行了2航次的大型底栖动物生态调查,20个采样站位共获得大型底栖动物55种,其中甲壳动物最多,有18种(占32.73%),其次是底栖鱼类(17种,占30.91%)、软体动物(16种,占29.09%),腔肠动物3种(5.45%),环节动物最少,只有1种(1.82%)。2航次共鉴定大型底栖动物优势种14种,其中葛氏长臂虾Palaemon gravieri、细巧仿对虾Parapenaeopsis tenella为2航次共有优势种,其余均为单一航次优势种,夏、秋季间种类更替率较高,为51.85%。平均生物量、丰度,夏季航次均分别高于秋季航次,方差分析表明生物量、丰度两航次间均存在显著差异(P0.05),远近岸间均不存在显著差异(P0.05)。对檀头山岛周围海域夏季和秋季大型底栖动物群落结构进行聚类分析和n MDS排序分析,结果表明,夏季、秋季20个站位均可划分成2个主要聚类组,对各聚类组内平均相似度贡献较大的物种主要是广温、广盐性的甲壳类动物,如东方口虾蛄Oratosquilla oratoria、中国毛虾Acetes chinensis、细螯虾Leptochela gracilis、葛氏长臂虾Palaemon gravieri、中华管鞭虾Solenocera crassicornis、三疣梭子蟹Portunus trituberculatus等。ABC曲线和多样性指数分析表明,檀头山岛周围海域大型底栖动物群落在秋季受到重度扰动,夏季未受到扰动。粒径分析结果显示檀头山岛周围海域沉积物主要是由较细颗粒的黏土和粉砂组成。CCA分析结果表明温度、盐度、水深、溶解氧是对大型底栖动物影响程度较大的环境因子。  相似文献   
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