Spatial zonation of macrobenthic fauna in Zhanjiang Mangrove Nature Reserve, Guangdong, China

The spatial zonation of macrobenthic fauna in the core region of Zhanjiang Mangrove Nature Reserve was studied with two transects vertical to the shoreline. The first transect was near Deyao Village where three faunal zones of the mangrove swamp could be divided into the following types from the high tide part to the low tide part: the Assiminea lutea-Uca arcuata-Paracleistostoma crassipilum zone, the Cleistostoma dilatatum-Macrophthalmus erato-Littoraria melanostoma zone, and the Paracleistostoma depressum-Cerithidae cingulata zone. Mollusck and crustacean exhibited the highest individual density in this transect. Mollusck mainly influenced the dynamics of community biomass as well as the species diversity index. In the second transect near Hongzhai Village, the following four faunal zones could be determined: the Littoraria melanostoma-Pseudoringicula sinensis-Ceratonereis burmensis zone, the Assiminea lutea-Cleistostoma dilatatum zone with a dominant species belonging to the Ellobiidae, Upogebia sp.-Paracleistostoma depressum zone, and the Metaplax sheni-Cerithidae cingulata zone. The crustacean showed the highest individual density in this transect. Similar to the Deyao transect, dynamics of community biomass and the species diversity index of the Hongzhai transect were mainly influenced by mollusck. By hierarchical clustering and nonmetric multidimensional scaling, the macrobenthic fauna communities could be divided into three and four groups in the Deyao and Hongzhai transects, respectively. These groups corresponded to different types of vegetation of the mangrove swamp. Taken together, our observations indicated that the spatial zonation of the macrobenthic fauna was mainly affected by the characteristics of the mangrove community, sediment characteristics and the tidal line.     

广东湛江红树林保护区大型底栖动物群落的空间分带

用生态样带研究了广东湛江红树林保护区高桥镇核心区大型底栖动物的空间分带。结果表明：德耀村红树剖面中出现的大型底栖动物优势种类为琵琶拟沼螺、悦目大眼蟹、扁平拟闭口蟹、宽身闭口蟹、黑口滨螺、等齿角沙蚕、弧边招潮和中华伪露齿螺。该剖面大型底栖动物从高潮位到低潮位可分为3个分布带：琵琶拟沼螺-弧边招潮-浓毛拟闭口蟹带；宽身闭口蟹．悦目大眼蟹．黑口滨螺带；扁平拟闭口蟹-珠带拟蟹手螺带。群落生物量的变化主要由软体动物所主导，栖息密度的变化主要由软体动物和甲壳动物所主导，多样性指数变化主要由软体动物所主导。红寨村红树剖面中出现的大型底栖动物优势种类为琵琶拟沼螺、蝼姑虾、扁平拟闭口蟹、宽身闭口蟹、耳螺科的一种、黑口滨螺、中华伪露齿螺、哈氏仿对虾、弧边招潮和等齿角沙蚕。该剖面大型底栖动物也可分为4个分布带：黑口滨螺-中华伪露齿螺-等齿角沙蚕带；琵琶拟沼螺-宽身闭口蟹-耳螺科的一种带；蝼蛄虾．扁平拟闭口蟹带；沈氏长方蟹-珠带拟蟹守螺带。群落生物量的变化也主要由软体动物所主导，栖息密度的变化主要由甲壳动物所主导，多样性指数变化主要由软体动物所主导。底栖动物群落的等级聚类和非参数多变量标序显示，大型底栖动物分带与红树植物群落类型相一致。大型底栖动物分带受红树植物群落类型影响的主要原因是不同红树植物群落间的群落特征、沉积物性质和所处潮位线存在差异。     

深圳福田红树林区底栖大型动物群落的空间分带及灌污的可能影响

本文自１９９１年４月至１９９３年１月对深圳福田红树林中底栖大型动物的空间分带及灌污的可能影响进行了研究。结果表明,该红树林湿地中主要出现的底栖动物为拟沼螺科,黑螺科,汇螺科,沙蟹科,方蟹科和弹涂鱼科种类。红树区内底栖动物从高潮位到低潮位可分为３个群落分布带：亮泽拟沼螺带;拟黑螺－褶痕相手蟹带;弧边招潮－印尼拟蟹守螺－刻纹拟沼螺带。群落的分带可能主要由潮位线,食物适应性及底质结构因素决定。林前泥滩底栖动物种类多样性最大,生物量最高。林内动物群落则表现出低种类多样性,高种群个体数的特点。群落总栖息密度的变化基本上由软体动物所主导。生活污水排灌对红树林中底栖大型动物的影响不明显,仅在排污口端引起少数污水动物种类的出现及群落总生物量轻微的升高。     

福建洛阳江口红树林湿地大型底栖动物多样性及季节变化

基于2013-2014年福建洛阳江口红树林湿地的周年调查资料, 研究了该湿地大型底栖动物的物种多样性现状、季节变化以及红树林恢复对底栖动物群落的影响。本次调查共鉴定大型底栖动物7门78种, 环节动物和节肢动物种类最为丰富, 节肢动物对总生物量贡献最大, 短拟沼螺(Assiminea brevicula)为本区第一优势种。林区底栖动物的密度和生物量明显低于光滩, 部分优势种仅在林区出现, 此外, 林区群落与光滩有显著差异。本区底栖动物的密度高值出现在冬、春季, 生物量高值出现在春、夏季, 群落结构季节变化明显。本区底栖动物种类组成特点反映出洛阳江口红树林处在年轻期, 群落的季节变化可能跟优势种的繁殖特点有关。研究结果也表明红树林植被会影响底栖动物群落结构, 林区群落已然不同于光滩, 与2009年调查结果相比, 林区底栖动物密度虽明显下降, 但褶痕拟相手蟹(Parasesarma plicata)数量增加, 是优势种之一。洛阳江口红树林和光滩支撑着不同的生物组成, 因此, 红树林恢复应当保持栖息地的多样性/异质性。     

Changes in the functional feeding groups of macrobenthic fauna during mangrove forest succession in Zhanjiang,China

Understanding the relationships between mangrove forest succession and the functional diversity of mangrove fauna could facilitate the restoration of mangrove ecosystems, which have been severely damaged in recent decades. The current report describes changes in macrobenthic functional diversity in a mangrove chronosequence that included a primary community (unvegetated shoal), an early community (Avicennia marina), a middle community (Aegiceras corniculatum), and a late community (Bruguiera gymnorrhiza?+?Rhizophora stylosa) in Zhanjiang, China. Phytophages were the dominant macrobenthic functional feeding group regardless of mangrove succession stage, sampling season, or macrobenthic faunal parameter (species richness, abundance, and biomass). As mangrove succession progressed, the proportions of macrobenthic species richness, abundance, or biomass represented by omnivores significantly increased (except for biomass and in the late stage; ranged from 0.065 to 0.230 and 0.033 to 0.368, respectively in wet season, and 0.000 to 0.192 and 0.000 to 0.396, respectively in dry season), while the proportions significantly decreased for detritivores during the dry season (ranged from 0.156 to 0.056, 0.107 to 0.019, and 0.066 to 0.005, respectively). Non-metric multi-dimensional scaling and PERMANOVA also indicated that the structure of macrobenthic faunal functional feeding groups was significantly affected by mangrove succession. Further analyses indicated that the changes in the relative dominance among macrobenthic faunal functional feeding groups during mangrove succession were mainly associated with changes in plant density, coverage/canopy density, and total nitrogen content of sediment, i.e., they were mostly associated with changes in food sources. The results increase our understanding of the relationship between benthic functional diversity and mangrove succession and could help guide mangrove restoration in China and around the world.     

厦门凤林红树林湿地大型底栖动物群落

为摸清厦门集美凤林红树林湿地的大型底栖动物群落结构及其多样性现状,2002年1、4、7和10月在厦门集美凤林红树林区进行大型底栖动物调查,4个季度共获得大型底栖动物42种。生物量优势种是软体动物门的珠带拟蟹守螺(Cerithideacingulata)和节肢动物门的弧边招潮(Ucaarcuata)。密度优势种是软体动物门的短拟沼螺(Assimineabrevicula)和环节动物门的沼蚓(Limnodriloidessp.)。集美凤林红树林区大型底栖动物年平均密度和年平均生物量分别为1,990ind./m2和139.0g/m2。密度的季节变化是:1月>4月>10月>7月,生物量的季节变化是1月>10月>4月>7月。聚类分析和数量分布表明,优势种珠带拟蟹守螺、短拟沼螺、弧边招潮和沼蚓的季节变化各不相同。与2002年10月深圳湾福田红树林区大型底栖动物群落的物种多样性指数平均值(0.56)比较,厦门凤林红树林区的平均值较高(2.66)。文中分析了影响大型底栖动物多样性的环境因素。     

乐清湾红树林和光滩大型底栖动物群落比较研究

2004年5月,对浙江乐清西门岛的人工红树林及周边滩涂进行大型底栖动物调查,共发现大型底栖动物18种,隶属6门7纲15科;主要是软体动物,节肢动物和环节动物.底上生活类群(groupofsurface,GS)种类数少于底内生活类群(group of surface below,GSB)种类数.通过在红树林、幼红树林和光滩三种生境的调查发现,幼红树林群落结构组成介于红树林和光滩之间,三种生境的大型底栖动物密度分别为452ind·m^-2,310ind·m^-2,620ind·m^-2,生物量分别为40.53g·m^-2,44.80g·m^-2和42.75g·m^-2.红树林区底栖动物的优势种为可口革囊星虫Phascolosoma esculenta和难解不等蛤Enigmonia aenigmatica.三种生境中,红树林的生物多样性和均匀度最高,优势度最小,造成这个现象的原因可能与红树林生境的复杂化有关.     

海南岛西海岸红树林软体动物多样性

为了掌握海南岛西海岸红树林软体动物多样性状况, 本文于2015-2016年对海南岛西海岸6个主要红树林分布区软体动物的种类组成、物种多样性和群落结构的时空变化进行了研究。共采集到软体动物57科201种, 主要优势种有珠带拟蟹守螺(Cerithidea cingulata)、绯拟沼螺(Assiminea latericea)、圆胖樱蛤(Pinguitellina cycladiformis)和斜肋齿蜷(Sermyla riqueti)等。年平均密度与平均生物量分别为324.13 ind./m²和142.88 g/m², 物种数、密度和生物量均高于北部湾沿岸的其他红树林。海南岛西海岸各红树林软体动物的密度和生物量均未呈现明显的季节变化, 软体动物密度存在空间上的显著差异。聚类分析结果显示, 在盐度、土壤结构和红树林群落存在差异的不同红树林, 软体动物种类组成相似度低。多因子AZTI海洋生物指数(M-AMBI)结果表明海南岛西海岸红树林软体动物群落未受明显扰动, 生态环境质量介于一般和优良之间, 但仍受到人类活动与外来植物入侵威胁, 因其在候鸟迁徙中的重要作用, 亟需加强管理与保护。     

Zonation of mangrove flora and fauna in a subtropical estuarine wetland based on surface elevation

In the context of sea‐level rise (SLR), an understanding of the spatial distributions of mangrove flora and fauna is required for effective ecosystem management and conservation. These distributions are greatly affected by tidal inundation, and surface elevation is a reliable quantitative indicator of the effects of tidal inundation. Most recent studies have focused exclusively on the quantitative relationships between mangrove‐plant zonation and surface elevation, neglecting mangrove fauna. Here, we measured surface elevation along six transects through the mangrove forests of a subtropical estuarine wetland in Zhenzhu Bay (Guangxi, China), using a real‐time kinematic global positioning system. We identified the mangrove plants along each transect and investigated the spatial distributions of arboreal, epifaunal, and infaunal molluscs, as well as infaunal crabs, using traditional quadrats. Our results indicated that almost all mangrove forests in the bay were distributed within the 400–750 m intertidal zone, between the local mean sea level and mean high water (119 cm above mean sea level). Mangrove plants exhibited obvious zonation patterns, and different species tended to inhabit different niches along the elevation gradient: Aegiceras corniculatum dominated in seaward locations while Lumnitzera racemosa dominated in landward areas. Mangrove molluscs also showed distinct patterns of spatial zonation related to surface elevation, independent of life‐form and season. The spatial distributions of some molluscs were correlated to the relative abundances of certain mangrove plants. In contrast, the spatial distributions of crabs were not related to surface elevation. To the best of our knowledge, this is the first study to explicitly quantify the influences of surface elevation on the spatial distributions of mangrove fauna. This characterization of the vertical ranges of various flora and fauna in mangrove forests provides a basic framework for future studies aimed at predicting changes in the structure and functions of mangrove forests in response to SLR.     

广东湛江保护区红树林种群的生物量及其分布格局

本文研究了广东湛江红树林自然保护区高桥镇红寨村及德耀村海滩红树植物的种群分布格局与生物量。结果表明：５年生桐花树群落、白骨壤群落、秋茄群落、１０年生木榄群落、３０年生红海榄群落的总生物量分别为５５４７５ｇ／ｍ２、１６３７０１ｇ／ｍ２、６２６４４８ｇ／ｍ２、４１３８４３ｇ／ｍ２、９６１０２０ｇ／ｍ２;其中地下部分生物量占总生物量的比例依次为３２２８％、４５４５％、４１３１％、２９８５％和２８２９％。计算得Ｓｈａｎｎｏｎ－Ｗｉｅｎｅｒ物种多样性指数为２２３２。种群的分布格局中桐花树、白骨壤、红海榄和秋茄种群为集群分布,而木榄种群为随机分布。     

Differences in macrobenthic faunal communities in mangrove wetland habitats (Zhanjiang,China) invaded and non-invaded by exotic cordgrass <Emphasis Type="Italic">Spartina alterniflora</Emphasis>

Mangroves are essential for maintaining local biodiversity and human well-being, and mangrove structure and functioning depend on the macrobenthos. Although exotic cordgrass, Spartina alterniflora, is an increasing threat to the mangrove wetlands (including the associated unvegetated shoals) of China, its effects on the macrobenthic fauna in such wetlands is poorly understood. The macrobenthic faunal communities were compared in (1) an Avicennia marina monoculture vs. an S. alterniflora-invaded A. marina stand (a mixture of A. marina and S. alterniflora) and in (2) an unvegetated shoal vs. an S. alterniflora-invaded shoal that had rapidly become an S. alterniflora monoculture in Zhanjiang, China. S. alterniflora invasion significantly increased plant density regardless of invaded habitat but significantly increased the contents of total carbon, organic matter, and total sulfur in the sediment only in the unvegetated shoal. The presence of S. alterniflora had little influence on indices of the macrobenthic faunal community in the A. marina monoculture, but significantly decreased the density and biomass of macrobenthic faunal community in the unvegetated shoal. These results indicate that the effects of S. alterniflora on the macrobenthic faunal community depend on which type of mangrove habitat is invaded. The composition of the macrobenthic faunal community was more similar between the invaded and non-invaded A. marina stand than between the invaded and non-invaded unvegetated shoal. Overall, the differences in the macrobenthic faunal community between invaded and non-invaded habitats were associated with increases in the sediment organic matter content and plant density.     

珠江口及邻近海域大型底栖动物多样性随盐度、水深的变化趋势

利用2006年7-8月(夏季)、2007年4-5月(春季)和2007年10-12月(秋季)珠江丰水期、平水期和枯水期3个航次在南中国海北部珠江口附近海域4条由河口、近岸到深水区调查断面的数据, 研究大型底栖动物多样性由河口-近岸-深水的变化趋势及与环境因子的关系。春季、夏季和秋季分别获得大型底栖动物273、256和148种, 各季节均以环节动物种类最多, 节肢动物次之。大型底栖动物种类数、丰度、生物量和Shannon-Wiener多样性指数均由河口向近岸海域升高, 再由近岸向外海深水区降低。Pielou均匀度深水区最高, 其次为近岸。河口和深水区大型底栖动物k-优势度曲线位于近岸浅水域曲线之上, 表明生物多样性由河口向近岸升高, 而由近岸向深水则降低。大型底栖动物与环境因子Pearson相关性分析表明, 春、秋季大型底栖动物种类数、丰度和生物量与水深呈显著的负相关, 秋季种类多样性指数和均匀度也与水深呈显著的负相关性, 而夏季仅生物量与水深呈显著的负相关; 春、秋季大型底栖动物种类数、生物量、丰度、多样性指数和种类均匀度与盐度的相关性不显著, 但是夏季大型底栖动物种类数、丰度、多样性指数和种类均匀度与盐度呈显著正相关。单位面积(0.2 m²)内, 珠江口及邻近海域大型底栖动物在近岸浅水区较深水区和河口生物多样性高, 且生物量丰富。     

A mangrove community in the New Hebrides, south-west Pacific

A general survey of the mangal at Port Stanley, Malekula, New Hebrides, the most extensive mangal in the archipelago, was conducted over an 11-day period in September/October 1971. Seventeen species of true mangrove tree and mangrove associates were recorded. As is characteristic of mangal, this flora was distributed in a zonal pattern, four zones being recognized. Certain anomalies in zonation were attributed to a recent episode of crustal uplift. The aquatic component of the fauna was dominated by molluscs (26 species) and Crustacea (20 species). The terrestrial vertebrate fauna consisted of 4 species of reptiles, 21 birds and 5 mammals.
The mangrove community at Port Stanley is an integral part of that of the Indo-West Pacific region. However it is much restricted in number of species, and reasons for this are suggested: distance from Malesia, lack of fresh water, and shallow soils with little silt deposition. Faunal impoverishment is clearly associated with floral impoverishment.     

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.     

Macrobenthos ofPotamogeton andMyriophyllum beds in the upper reaches of Canal de Mira (Ria de Aveiro,NW Portugal): Community structure and environmental factors

The community structure of the macrobenthic fauna (>0.5 mm) ofPotamogeton andMyriophyllum beds of the upper reaches of Canal de Mira (0.5–2) and of macrofauna density (369, 240 ind m^–2).Potamopyrgus jenkinsi, Corophium multisetosum andLimnodrilus hoffmeisteri are dominant species in the study area. The community of station 1 includes an important set of taxa usually associated to freshwater habitats (oligochaetes, leeches and insect larvae) whilst in station 3 typically estuarine species (Cyathura carinata, Leptocheirus pilosus, Nereis diversicolor, Streblospio shrubsolii) occur. A succession of peak densities of different taxonomic groups during the year indicates seasonal variation in the community structure. The faunal assemblage of the study area is compared with similar ones in NE Atlantic and Mediterranean coastal systems.     

Variations spatiales et saisonnières de la structure de groupements macrobenthiques littoraux en climat froid

Spatio-temporal variations of macrobenthic community structure were studied in the littoral zone of the Saint-Lawrence River (Québec). Its thermal regime is characterized by steep seasonal gradients from April to November and by a long ice-cover period with formation of an icefoot. Six sites were sampled each season for one year. Temporal variations are less important than spatial variations. They are mainly seasonal and depend on emergence and recruitment periods and on migrations but there are also long-term variations. An increase of the mean diversity index of sites corresponds to an increase of seasonal variations of community profile and to a decrease of seasonal variations of organism abundance; it is explained by a better exploitation of benthic resources rather than by environment stability. Spatial variations of community structure depend mainly on vegetation abundance. There is no faunal zonation corresponding to the icefoot action. In sites where Gastropods are abundant, icefoot does not change community profile but it explains diminutions of density and of species diversity. Chironomids are little affected by this phenomenon.     

Altitudinal species turnover in southern Tanzania shown by anurans: Some zoogeographical considerations

A transect was used to investigate the pattern of altitudinal species turnover shown by the rich fauna of frogs and toads in southeastern Tanzania, and to compare the pattern with those shown by transects taken further south. The transect, taken from the Udzungwa range to the southeastern coast, was divided into 50 m intervals. As with the southern transects, there appears to be a major grouping into lowland and highland sets, with opposing and overlapping subtraction margins that form a replacement‐transition zone. A distributionally complex assemblage of species occurs in this zone. When a similarity value (the Dice‐S?rensen index, expressed as a percentage) taken between the montane ridge and lowland faunas was compared with those of the southern transects, a markedly higher species turnover (low similarity value) is shown in Tanzania. Both lowland and highland faunas have more species than equivalent faunas to the south; the highland fauna is particularly rich in genera not known to occur further south. Yet overall, the pattern of altitudinal turnover shown in the Tanzanian transect is in agreement with the pattern shown in the southern transects. The transects discussed in this paper, combined with other evidence, suggest a need for re‐evaluating the common practice of including all sub‐Saharan Africa in a single so‐called Afrotropical Region.     

Distribution and structure of macrobenthic fauna in the eastern Laptev Sea in relation to environmental factors

The Laptev Sea still ranks among the less known regions of the world’s ocean. Here, we describe the distribution and composition of macrobenthic communities of the eastern shelf and identify key environmental control factors. Samples were collected from dredge catches carried out at 11 stations at depths between 17 and 44 m in August/September 1993 during the TRANSDRIFT I cruise of the Russian R/V “Ivan Kireev.” A total of 265 species were identified from the samples, mostly crustaceans (94). Species numbers per station ranged from 30 to 104. Macrobenthic community distribution clearly showed a depth zonation, consisting of a “Shallow” zone (<20 m), dominated by the crustaceans Mysis oculata (Mysidacea) and Saduria entomon (Isopoda) as well as molluscs, an “Intermediate” zone (20–30 m), characterised by a clear dominance of the bivalve Portlandia arctica, and a “Deep” zone (>30 m) with bivalves P. arctica and Nuculoma bellotii as well as brittle stars Ophiocten sericeum and Ophiura sarsi being most abundant. According to a correlation analysis between faunal and environmental data a combination of duration of ice cover and water depth, respectively, showed the highest affinity to macrobenthic distribution. We conclude that the food input to the benthos, which is largely related to ice-cover regime, and the stress due to the pronounced seasonal salinity variability, which is primarily related to water depth, are prime determinants of macrobenthic community distribution and major causes of the prominent depth zonation in the Laptev Sea. Within the depth zones, sediment composition seems to be most significant in controlling the patterns in the distribution of the benthic fauna.     

中街山列岛岩相潮间带大型底栖动物的群落格局

于2006年9月和2007年7月在中街山列岛4个有居民海岛岩相潮间带设立8个断面,对大型底栖动物的群落结构进行了调查。共获得大型底栖动物34种,其中腔肠动物1种,环节动物3种,甲壳动物10种,软体动物20种。优势种有日本笠藤壶(Tetraclita japonica)、紫贻贝(Mytilus edulis)和节蝾螺(Turb articulatus)等4种。以季节和站位为因子对多样性指数进行双因素方差分析,结果表明只有夏、秋季丰富度指数(P=0.028)存在显著差异,其他指数的方差分析没有显著差异(P>0.05)。3个潮带4个岛屿共12个站位的聚类分析和MDS标序分析表明,12个群落可分为3组(Ⅰ、Ⅱ和Ⅲ组)。大型底栖动物ABC曲线分析表明底栖动物群落尚未受到干扰。     

海南清澜港红树林滩涂大型底栖动物初步研究

对海南清澜港红树林滩涂大型底栖动物进行了定性及定量调查,记录到大型底栖动物４５种,隶属于４个门,２６个科。其中软体动物３１种,占记录到物种数的６８９％;甲壳动物１０种,占记录到物种数的２２２％。优势种是珠带拟蟹手螺（ＣｅｒｉｔｈｉｄｅａｃｉｎｇｕｌａｔａＧｍｅｌｉｎ）、古氏滩栖螺（ＢａｔｉｌａｒｉａｃｕｍｉｎｇｉＣｒｏｓｅ）、中国紫蛤（ＨｉａｔｕｌａｃｈｉｎｅｎｓｉｓＭｏｒｃｈ）及奥莱彩螺（ＣｌｉｔｈｏｎｏｕａｌａｎｉｅｎｓｉｓＬｅｓｏｎ）。大型底栖动物的生物量平均１９８５ｇ／ｍ２、栖息密度３５２４个／ｍ２。软体动物的生物量占到９９％,这可能与取样设在中、低潮区有关。