Community structure and temporal variability of ichthyoplankton in North Brazilian mangrove creeks

The species composition and dynamics of fish larvae in three mangrove creeks located in the Caeté Estuary (north Brazil) were studied monthly using a trap net during diurnal ebb tides. A total of 109 954 larvae, representing 25 families and 54 species, were collected from October 1996 to October 1997. The community was dominated numerically by a few species, a feature common for other estuarine fish populations. The most abundant taxa were estuarine species, namely the eleotrid Guavina guavina (46·7%) and the engraulid Anchovia clupeoides (14·9%). The sciaenid Cynoscion acoupa was the only marine species that used the mangroves extensively as a nursery site, occurring mainly at the postflexion stage. The size distribution of G. guavina did not produce shifting modes, indicating continuous transport out of the mangroves by tidal currents. Significantly lower species richness was observed in the late rainy season, primarily due to the emigration of marine species. Intermediate seasons were characterized by more complex larval fish assemblages. The temporal trends of the dominant species was influenced to a great degree by their life history strategy.     

雷州半岛红树林鱼类群落结构及其与人类活动强度的关系

水产养殖、城镇建设等引起的土地利用变化使红树林生态系统遭受严重破坏,是红树林生物多样性面临的主要威胁之一。了解雷州半岛红树林鱼类群落结构,探究人类活动强度对鱼类群落结构的影响,对红树林鱼类资源保护至关重要。基于2021—2022年雷州半岛7片红树林共21条潮沟的鱼类数据,结合周边土地利用数据,研究鱼类群落结构及其与土地利用类型的关系。结果显示,共采集鉴定鱼类49种,隶属于8目25科,鲈形目鱼类最多,共33种占总种类数的75.5%,其中,虾虎鱼科种数最多,共15种占30.6%;食性上,主要为杂食性和肉食性鱼类,分别为53.06%和44.90%;各红树林Shannon-Wiener多样性指数在秋冬春三季的变化范围均为0—2.5,Simpson多样性指数均为0—0.9;各红树林鱼类个体数、物种数和生物量均存在显著差异(P>0.05);除秋季北潭与流沙湾的鱼类群落无显著差异(P>0.05)外,其余红树林间的鱼类群落在三个季度均有显著差异(P<0.05);人类活动强度、红树林面积和东西岸对鱼类多样性指数、个体数、物种数和生物量均有显著的主效应和交互效应(P<0.05);青...     

Firefly distribution and abundance on mangrove vegetation assemblages in Sepetang estuary,Peninsular Malaysia

Pteroptyx fireflies are commonly reported to congregate in large numbers in mangroves. Not much is known about the relationships between firefly distribution and abundance with specific mangrove vegetation assemblages. We conducted a study to investigate the vegetation assemblages that structure the distribution and abundance of Pteroptyx tener in Peninsular Malaysia. The distribution and abundance of fireflies were assessed along an 8 km stretch of mangroves in Sepetang estuary using visual assessment. Statistical analysis was carried out to test the correlation between length of display section and percentage cover of P. tener colonies and the relationship between percentage cover of fireflies with different vegetation assemblages. Five distinct vegetation assemblages were identified comprising different combination of four mangrove species. It was found that shorter display sections had higher percentage cover of P. tener colonies. In addition, vegetation assemblage which consisting of mainly Sonneratia caseolaris and Nypa fruticans was the most preferred type. The results of this study point to the necessity to consider not only a single mangrove species but the entire vegetation assemblage for firefly conservation.     

福建沿岸红树林湿地多毛类生态分布

根据2009年至2012年在福建沿岸5块典型红树林湿地所作的调查资料,分析了福建沿岸红树林湿地多毛类的物种多样性、生态分布特点以及与环境因子的关系。研究区域春、秋两季共记录多毛类动物45种,其中沙蚕科、海稚虫科和小头虫科3个科种类最为丰富,种类属性为低盐或广盐性种类。多毛类平均密度和生物量分别为190个/m2和2.17 g/m2,样地×季节双因素方差分析表明,密度在不同样地间差异显著,密度和生物量的季节变化均为春季显著高于秋季。此外,林外光滩的多毛类数量要高于林内,不同样地的摄食群组成各异。红树林断面的平均种类数和多样性指数H'与沉积物粘土含量呈显著负相关,与多毛类类群的大尺度空间分布特征关联最为紧密的因子为地理纬度。     

广东电白人工红树林大型底栖动物群落的功能特征及其影响因子

随着人们对红树林生态价值的重视,近年来全球范围内陆续开展了红树林人工造林活动。以往对红树林造林成效的评价,主要集中在面积、成活率等数量指标上,很少针对红树林的生态功能进行评价。本研究对华南沿海水东湾人工红树林大型底栖动物群落的功能特征进行了调查,并分析其与环境参数的关联性。结果表明:通过1年的野外采样,共记录了5门6纲40种大型底栖动物,不同树种、林型的红树林中大型底栖动物群落的栖息密度、生物量以及功能多样性存在显著差异,无瓣海桑(Sonneratia apetala)人工林与白骨壤(Avicennia marina)天然林的生态功能较为接近。与拉关木(Laguncularia racemosa)人工纯林相比,人工混交林能满足更多功能特征底栖动物的生境利用需求。水土理化性质与某些大型底栖动物的功能性状存在显著的相关性,红树林定居后引起生境中环境参数的改变,是造成大型底栖动物群落多样化的主要原因。     

Altitudinal gradients in stream fish diversity and the prevalence of diadromy in the Sixaola River basin,Costa Rica

Landscape-scale patterns of freshwater fish diversity and assemblage structure remain poorly documented in many areas of Central America, while aquatic ecosystems throughout the region have been impacted by habitat degradation and hydrologic alterations. Diadromous fishes may be especially vulnerable to these changes, but there is currently very little information available regarding their distribution and abundance in Central American river systems. We sampled small streams at 20 sites in the Sixaola River basin in southeastern Costa Rica to examine altitudinal variation in the diversity and species composition of stream fish assemblages, with a particular focus on diadromous species. A set of environmental variables was also measured in the study sites to evaluate how changes in fish assemblage structure were related to gradients in stream habitat. Overall, fish diversity and abundance declined steeply with increasing elevation, with very limited species turnover. The contribution of diadromous fishes to local species richness and abundance increased significantly with elevation, and diadromous species dominated assemblages at the highest elevation sites. Ordination of the sampling sites based on fish species composition generally arranged sites by elevation, but also showed some clustering based on geographic proximity. The dominant gradient in fish community structure was strongly correlated with an altitudinal habitat gradient identified through ordination of the environmental variables. The variation we observed in stream fish assemblages over relatively small spatial scales has significant conservation implications and highlights the ecological importance of longitudinal connectivity in Central American river systems.     

Preliminary analysis of the fish species of the Pacific Central American Mangrove of Zancudo, Golfo Dulce, Costa Rica

The aim of the present paper is to provide first information on the mangrove fish community of the tropical fjord-like Golfo Dulce (GD), to study its importance for fish diversity and fisheries in the area and to give preliminary results on its spatial–temporal variation. Eighty-two species belonging to 30 families were identified. More than half of them belonged to the estuarine transient fish group and only 14 species were estuarine resident, highlighting the importance of the Zancudo mangrove as a transition area. The most diverse families were Sciaenidae, Carangidae and Haemulidae for both rainy and dry seasons. As much as 71% of the species captured were of first or second grade economic value and only 11% had no commercial value. Comparing our data with fisheries and scientific surveys inside and outside the gulf suggests the importance of the Zancudo mangrove for regional fisheries and fish diversity. Multidimensional scaling (MDS) indicated gradual changes in the fish community composition from the river mouth to the more internal sampling sites for rainy and dry seasons. Moreover, shifts in abundance and species composition between seasons were observed, mainly an increase in the differences between the boundaries and the central zones of the mangrove. These changes were attributed to the higher salinity differences between sites during the dry season forcing the occasional visitor fish downstream and freshwater fish taxa upstream. While the results contribute to initiatives for participative fisheries management in the region, further studies are needed to analyse the variations in detail.     

六种海桑属红树植物根际真菌特征及其影响因子

真菌多样性是植物根际生态系统的重要构成与植物健康稳定的重要指标。海桑属是红树林的先锋物种,采用真菌ITS1区高通量测序方法,分析了六种海桑属红树根际真菌的组成和多样性,结合土壤理化性质探讨影响不同植物根际真菌群落组成差异的因素。结果显示,根际真菌隶属于7门、96科、155属,子囊菌门作为优势菌门在海桑属不同红树中相对丰度无显著差异,都超过27%,但次优势的担子菌门丰度含量有差异;属水平上,优势菌属的丰度含量不同,曲霉属在卵叶海桑的丰度最高(29.57%),在海南海桑最低(3.47%)。六种红树植物根际存在特有的代表类群,如无瓣海桑的马拉色菌(9.31%)和毛腐菌属(10.05%),海南海桑中的Talaromyces(19.61%)和Acremonium(13.58%)。比较多样性指数Simpson和Shannon,发现拟海桑是六种植物中丰度最高的,卵叶海桑最低。RDA分析发现子囊菌门与全磷含量呈显著负相关,担子菌门与速效钾呈明显正相关。六种海桑属红树植物根际核心物种分析表明,优势真菌类群曲霉属和一些低丰度的真菌类群,通过降解有机质参与碳循环,对根际土壤生态系统的稳定起重要作用。六种海桑...     

Habitat Use by Fishes in Coral Reefs,Seagrass Beds and Mangrove Habitats in the Philippines

Understanding the interconnectivity of organisms among different habitats is a key requirement for generating effective management plans in coastal ecosystems, particularly when determining component habitat structures in marine protected areas. To elucidate the patterns of habitat use by fishes among coral, seagrass, and mangrove habitats, and between natural and transplanted mangroves, visual censuses were conducted semiannually at two sites in the Philippines during September and March 2010–2012. In total, 265 species and 15,930 individuals were recorded. Species richness and abundance of fishes were significantly higher in coral reefs (234 species, 12,306 individuals) than in seagrass (38 species, 1,198 individuals) and mangrove (47 species, 2,426 individuals) habitats. Similarity tests revealed a highly significant difference among the three habitats. Fishes exhibited two different strategies for habitat use, inhabiting either a single (85.6% of recorded species) or several habitats (14.4%). Some fish that utilized multiple habitats, such as Lutjanus monostigma and Parupeneus barberinus, showed possible ontogenetic habitat shifts from mangroves and/or seagrass habitats to coral reefs. Moreover, over 20% of commercial fish species used multiple habitats, highlighting the importance of including different habitat types within marine protected areas to achieve efficient and effective resource management. Neither species richness nor abundance of fishes significantly differed between natural and transplanted mangroves. In addition, 14 fish species were recorded in a 20-year-old transplanted mangrove area, and over 90% of these species used multiple habitats, further demonstrating the key role of transplanted mangroves as a reef fish habitat in this region.     

Restoration of Aegiceras corniculatum mangroves in Jiulongjiang Estuary changed macro-benthic faunal community

Macro-benthic faunal communities were compared between non-vegetation mudflat and Aegiceras corniculatum mangroves with different ages in Jiulongjiang Estuary, China. Faunal species number was highest in the mature mangrove and was higher in mangroves than in the mudflat, as snails and some crustaceans species were only collected in mangroves. The 5-year-old mangrove had the highest infaunal abundance and crustacean biomass. Snails had more abundance in the young mangroves. Uca arcuata was the dominant crab species in the non-vegetation mudflat and 5-year-old mangrove. Mangrove vegetation and sediment characteristics analyses indicated different habitats due to A. corniculatum mangrove restoration. However, overall poor correlations between faunal assemblage and sediment properties indicated that sediment properties were not the major factors influencing faunal distribution.     

Subtropical Brazilian mangroves as a refuge of crab (Decapoda: Brachyura) diversity

This study characterized seven mangrove areas of different sizes, located on the southeastern Brazilian coast, with respect to their sediment and vegetation features. We also estimated the richness and composition of the brachyuran assemblages in these mangroves. Crab, vegetation and sediment data were collected during low tide. The larger mangroves showed richer and complex forests, and may be more ecologically stable than smaller mangroves. Twenty-eight species of crabs were recorded, members of nine families: Panopeidae, Pinnotheridae, Gecarcinidae, Grapsidae, Sesarmidae, Varunidae, Ocypodidae, Ucididae, and Portunidae. Ocypodoidea predominated over Grapsoidea in the smaller mangrove areas in pioneer stages of forest establishment, whereas the opposite was recorded for larger and more stable mangroves, where the forest can reach advanced stage of development. Comprido is a small mangrove, but its crab assemblage was similar to the larger ones, probably because of other factors not investigated here (e.g., megalopa settling rate). This study provided basic knowledge for developing conservation strategies for vulnerable mangrove ecosystems.     

Biogeographic patterns in major marine realms: function not taxonomy unites fish assemblages in reef,seagrass and mangrove systems

We examine the effects of different biogeographic histories on assemblage composition in three major marine habitats in two biogeographically distinct marine realms. Specifically, we quantify the taxonomic and functional composition of fish assemblages that characterise coral reef, seagrass and mangrove habitats, to explore the potential effects of biogeographic history and environment on assemblage composition. The three habitats were surveyed in the Caribbean and on the Great Barrier Reef using a standardised underwater visual census method to record fish size and abundance data. The taxonomic composition of assemblages followed biogeographic expectations, with realm‐specific family‐level compositions. In marked contrast, the functional composition of assemblages separated habitats regardless of their biogeographic locations. In essence, taxonomy characterises biogeographic realms while functional groups characterise habitats. The Caribbean and Indo‐West Pacific have been separated for approximately 15 million years. The two realms have different taxonomic structures which reflect this extended separation, however, the three dominant shallow‐water marine habitats all retain distinct functional characteristics: seagrass fishes are functionally similar regardless of their taxonomic composition or biogeographic location. Likewise, for coral reefs and mangroves. The results emphasise the advantages and limitations of taxonomic vs. functional metrics in evaluating patterns. Taxonomy primarily reflects biogeographic and evolutionary history while functional characteristics may better reflect ecological constraints.     

Reef fish assemblages in north-western Sri Lanka: distribution patterns and influences of fishing practises

The distribution and abundance of reef fishes in relation to habitat structure were studied within Bar Reef Marine Sanctuary (BRMS) and on an adjacent reef, disturbed by destructive fishing techniques, in north-western Sri Lanka, by visually censusing 135 species groups using fifty metre belt-transects. Two types of continental shelf patch-reefs are found in the study area: coral reefs and sandstone reefs, which are divided into distinct habitats, four for the coral reef (shallow reef flat, shallow patch reef, deep reef flat and Porites domes) and two for the sandstone reef (structured sandstone-reef and flat sandstone-reef). Fish assemblages varied in structure between reef types and among habitats within reef types. Functional aspects of habitat structure and composition, such as available food and shelter, seemed to be important factors influencing distribution patterns. The strongest separation in the organisation of fish assemblages in BRMS was between reef types: 19% of all species were confined to the coral-reef patches while 22% were restricted to the sandstone reef patches and 59% were represented on both reef types. In terms of distribution among habitats, 21% of all species were restricted to one habitat while only 1.5% were present in all. The highest density of fish was in the coral reef habitats while highest species diversity was found in the most structurally complex habitat: the structured sandstone-reef. This habitat also had the highest proportion of species with restricted distribution. Planktivores were the most abundant trophic group in BRMS, and the species composition of the group varied among habitats. The comparison of the disturbed reef with BRMS suggested that habitat alteration caused by destructive fishing methods has strongly influenced the fish community. Within the fished area the structure of the fish assemblages was more heterogeneous, fish abundance was lower by an order of magnitude and species numbers were lower than in BRMS.     

Differences in root architecture influence attraction of fishes to mangroves: A field experiment mimicking roots of different length, orientation, and complexity

Benthic structure plays an important role as shelter and feeding habitat for demersal fauna. While many studies have investigated the relationship between structural complexity of aquatic vegetation and the number of species or abundance of motile organisms, little is known of the attractiveness of submerged mangrove roots. We tested the importance of various root attributes in attracting fish species in a field experiment using different artificial mangrove units (AMUs) with PVC pipes mimicking roots to exclude interaction with other environmental and biotic factors. We manipulated length, vertical orientation, and three-dimensional structural complexity of root mimics in the AMUs to explore their effects on the fish community variables: fish abundance, number of species and community composition. Pipe length and three-dimensional structure did not have an effect on fish community variables. Vertical pipe orientation had a significant effect and AMUs with standing pipes showed higher total fish abundances and number of species than AMUs with hanging pipes. Also community composition differed greatly between AMUs with standing versus hanging pipes. At species level, demersal fish species mainly occupied AMUs with standing pipes and occurred only at very low abundances when hanging pipes dominated in the AMUs; in contrast, the semi-pelagic swimmer Sphyraena barracuda showed a trend of higher abundance in AMUs with mainly hanging pipes. When analyzed across all AMUs, fish abundances of demersal as well as semi-pelagic species decreased significantly with increasing interspatial pipe distance among AMUs, suggesting that distance to refuge may be the underlying mechanism for the observed patterns. The above findings are important in the context of the worldwide degradation of mangroves, because human alteration to mangrove vegetation affects its structure and thus composition and size of fish communities.     

Denaturing gradient gel electrophoresis and barcoded pyrosequencing reveal unprecedented archaeal diversity in mangrove sediment and rhizosphere samples

Mangroves are complex ecosystems that regulate nutrient and sediment fluxes to the open sea. The importance of bacteria and fungi in regulating nutrient cycles has led to an interest in their diversity and composition in mangroves. However, very few studies have assessed Archaea in mangroves, and virtually nothing is known about whether mangrove rhizospheres affect archaeal diversity and composition. Here, we studied the diversity and composition of Archaea in mangrove bulk sediment and the rhizospheres of two mangrove trees, Rhizophora mangle and Laguncularia racemosa, using denaturing gradient gel electrophoresis (DGGE) and pyrosequencing of archaeal 16S rRNA genes with a nested-amplification approach. DGGE profiles revealed significant structural differences between bulk sediment and rhizosphere samples, suggesting that roots of both mangrove species influence the sediment archaeal community. Nearly all of the detected sequences obtained with pyrosequencing were identified as Archaea, but most were unclassified at the level of phylum or below. Archaeal richness was, furthermore, the highest in the L. racemosa rhizosphere, intermediate in bulk sediment, and the lowest in the R. mangle rhizosphere. This study shows that rhizosphere microhabitats of R. mangle and L. racemosa, common plants in subtropical mangroves located in Rio de Janeiro, Brazil, hosted distinct archaeal assemblages.     

春、夏季舟山渔场及其邻近海域鱼类群落格局

根据2006年8月和2007年4月在舟山渔场及其邻近海域渔业资源和环境调查所获得的数据,采用非线性多维标度（MDS）和典范对应分析（CCA）方法研究了该海域的鱼类群落种类组成及群落特征.结果表明： 春季该海域共捕获鱼类62种,隶属11目36科56属,主要优势种为六丝钝尾虾虎鱼（Amblychaeturichthys hexanema）和小黄鱼（Larimichthys polyactis）,两种丰度占总丰度的82.9%;夏季共捕获鱼类58种,隶属于11目38科51属,主要优势种为六丝钝尾虾虎鱼、短鳄齿鱼（Champsodon snyderi）、前肛鳗（Dysomma anguillaaris）和发光鲷（Acropoma japonicum）,其丰度占总丰度的60.8%.春、夏两季20个站位均可划分为3个组.春、夏季出现率大于5.0%的鱼类分别有26种和30种,并且分别相应形成2个和3个组群.     

Mangrove Habitat Use by Juvenile Reef Fish: Meta-Analysis Reveals that Tidal Regime Matters More than Biogeographic Region

Identification of critical life-stage habitats is key to successful conservation efforts. Juveniles of some species show great flexibility in habitat use while other species rely heavily on a restricted number of juvenile habitats for protection and food. Considering the rapid degradation of coastal marine habitats worldwide, it is important to evaluate which species are more susceptible to loss of juvenile nursery habitats and how this differs across large biogeographic regions. Here we used a meta-analysis approach to investigate habitat use by juvenile reef fish species in tropical coastal ecosystems across the globe. Densities of juvenile fish species were compared among mangrove, seagrass and coral reef habitats. In the Caribbean, the majority of species showed significantly higher juvenile densities in mangroves as compared to seagrass beds and coral reefs, while for the Indo-Pacific region seagrass beds harbored the highest overall densities. Further analysis indicated that differences in tidal amplitude, irrespective of biogeographic region, appeared to be the major driver for this phenomenon. In addition, juvenile reef fish use of mangroves increased with increasing water salinity. In the Caribbean, species of specific families (e.g. Lutjanidae, Haemulidae) showed a higher reliance on mangroves or seagrass beds as juvenile habitats than other species, whereas in the Indo-Pacific family-specific trends of juvenile habitat utilization were less apparent. The findings of this study highlight the importance of incorporating region-specific tidal inundation regimes into marine spatial conservation planning and ecosystem based management. Furthermore, the significant role of water salinity and tidal access as drivers of mangrove fish habitat use implies that changes in seawater level and rainfall due to climate change may have important effects on how juvenile reef fish use nearshore seascapes in the future.     

典型红树林生态系统藻类多样性及其在生态过程中的作用

藻类是红树林生态系统重要的生物类群, 根据生态习性可分为浮游植物、底栖微藻和大型藻类三个生态类群, 它们在红树林生态系统生物多样性、初级生产、元素循环等方面起着重要作用。但在红树林生态系统中, 关注重点多集中在红树植物和动物, 对其中的藻类重视不够, 且多数研究集中在近20年以及亚洲的红树林区。事实上, 红树林生态系统藻类非常丰富, 其多样性研究有助于深入揭示红树林生态系统的结构与功能。本文介绍了红树林生态系统藻类的组成类群及其重要性, 重点对红树林区浮游植物、底栖硅藻和大型海藻的种类组成、地理分布及其与初级生产力、水质污染、元素循环、碳库形成等生态过程中的作用的研究动态和进展等进行了总结。根据已有研究, 红树林区浮游植物和底栖硅藻的种类数一般为几十到上百种, 其中硅藻在种类和数量上都占绝对优势, 它们是重要的初级生产者、饵料生物和水质污染指示生物; 红树林区底栖大型藻类主要由红藻、绿藻、褐藻、蓝藻组成, 绿藻的种类较多, 红藻在数量上占优势; 藻类是红树林湿地碳库的重要贡献者, 在红树林湿地生态系统碳汇和碳循环中起重要作用。红树林生态系统是个高度动态和异质的系统, 今后应加强红树林藻类多样性的长周期、大尺度变化及不同生境藻类的综合研究, 关注大陆径流和潮汐对藻类多样性和蓝碳的影响, 借助沉积物藻类记录, 探明红树林区藻类的长周期变化, 反演气候变化和人类活动对红树林生态系统的影响过程和机制。     

Coexisting mangrove-coral habitat use by reef fishes in the Caribbean

We conducted visual fish surveys in coexisting mangrove-coral (CMC) habitats in Panama to analyze the effect of coral presence in mangrove habitats on the fish assemblage. Our study revealed that CMC habitats harbor distinct fish assemblages compared to mangrove habitats without coral, with greater species richness and increased herbivore abundance. Abstract in Spanish is available with online material.