Leigh-Ann Smit, Janine B. Adams, Sarah A. Hawkes, Nasreen Peer, Gavin M. Rishworth
ABSTRACT: Salt marsh productivity has historically been viewed as being driven primarily by bottom-up processes, but recent studies in North America, Europe, Asia and South America have shown that top-down forces by grazers also structure marsh vegetation. This generality of grazing pressure has not been tested to date in African salt marshes. Here, we investigated whether dominant crabs in South Africa’s estuarine marshes consume live plants and whether that interaction has direct effects on the foundational species Spartina maritima. We employed natural surveys, lab feeding trials, diet analysis and field experiments. Although we found no significant relationships between crabs and marsh plant structure in surveys, gut contents and stable isotope analysis showed that S. maritima is present but not prominent in their diet. All S. maritima components were consumed. Manipulation of crab density and size structure in the field (crabs >5 mm excluded) revealed small effects on S. maritima stem density and aboveground biomass compared to controls. Combined, this research demonstrates that crabs in these South African marshes do indeed eat live cordgrass, and their effects appear to be density dependent. Top-down impacts on marsh plants were not detected by natural density correlations, probably due to the different scales at which data were collected compared to field experiments. These results establish that grazing of live foundational marsh plants is globally common. Future studies in these systems should manipulate crab density through addition experiments or predator exclusions to understand the impact of crabs at high densities and what forces regulate their populations.
摘要：盐沼的生产力历来被认为主要由自下而上的过程驱动，但最近在北美、欧洲、亚洲和南美洲进行的研究表明，食草动物自上而下的作用力也会影响沼泽植被的结构。迄今为止，这种放牧压力的普遍性尚未在非洲盐沼中得到验证。在这里，我们研究了南非河口沼泽中的优势螃蟹是否会吃活体植物，以及这种相互作用是否会对基础物种 Spartina maritima 产生直接影响。我们采用了自然调查、实验室喂食试验、饮食分析和野外实验等方法。虽然我们在调查中没有发现螃蟹与沼泽植物结构之间有明显的关系，但肠道内容物和稳定同位素分析表明，S. maritima存在于螃蟹的食物中，但并不突出。所有 S. maritima 成分都被吃掉了。与对照组相比，在野外操纵螃蟹密度和大小结构（不包括 5 毫米的螃蟹）对 S. maritima 茎干密度和地上生物量的影响较小。综合来看，这项研究表明，南非沼泽中的螃蟹确实吃活的灯心草，而且它们的影响似乎取决于密度。沼泽植物受到的自上而下的影响无法通过自然密度相关性检测出来，这可能是由于收集数据的尺度与野外实验不同。这些结果证明，全球范围内普遍存在放牧活体沼泽基础植物的现象。未来对这些系统的研究应通过添加实验或排除捕食者来控制螃蟹密度，以了解高密度螃蟹的影响以及是什么力量在调节它们的种群。
{"title":"Proportional top-down effects of grapsoid crabs on growth of Spartina maritima cordgrass in southern African salt marshes","authors":"Leigh-Ann Smit, Janine B. Adams, Sarah A. Hawkes, Nasreen Peer, Gavin M. Rishworth","doi":"10.3354/meps14612","DOIUrl":"https://doi.org/10.3354/meps14612","url":null,"abstract":"ABSTRACT: Salt marsh productivity has historically been viewed as being driven primarily by bottom-up processes, but recent studies in North America, Europe, Asia and South America have shown that top-down forces by grazers also structure marsh vegetation. This generality of grazing pressure has not been tested to date in African salt marshes. Here, we investigated whether dominant crabs in South Africa’s estuarine marshes consume live plants and whether that interaction has direct effects on the foundational species <i>Spartina maritima</i>. We employed natural surveys, lab feeding trials, diet analysis and field experiments. Although we found no significant relationships between crabs and marsh plant structure in surveys, gut contents and stable isotope analysis showed that <i>S. maritima</i> is present but not prominent in their diet. All <i>S. maritima</i> components were consumed. Manipulation of crab density and size structure in the field (crabs >5 mm excluded) revealed small effects on <i>S. maritima</i> stem density and aboveground biomass compared to controls. Combined, this research demonstrates that crabs in these South African marshes do indeed eat live cordgrass, and their effects appear to be density dependent. Top-down impacts on marsh plants were not detected by natural density correlations, probably due to the different scales at which data were collected compared to field experiments. These results establish that grazing of live foundational marsh plants is globally common. Future studies in these systems should manipulate crab density through addition experiments or predator exclusions to understand the impact of crabs at high densities and what forces regulate their populations.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"25 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141786196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Christophe Pampoulie, Aril Slotte, Guðmundur J. Óskarsson, Guðbjörg Ólafsdóttir, Jan Arge Jacobsen, Hóraldur Joensen, Sindri Karl Sigurðsson, Sæmundur Sveinsson, Leif Andersson, Anna Kristin Daníelsdóttir, Davíð Gíslason
ABSTRACT: Atlantic herring Clupea harengus feeding in the Norwegian Sea are assumed to consist of Norwegian spring spawners (NSSH), Icelandic summer spawners (ISSH) and North Sea autumn spawners (NSAH). Putative Norwegian autumn spawners (NASH), Faroese autumn (FASH) and spring (FSSH) spawners also feed in the area. However, until there is a method to discriminate between populations in mixed samples, fishery and survey data from the Norwegian Sea will be solely attributed to the predominating NSSH, ultimately causing biased stock assessments. Hence, we evaluated if a panel of 120 single nucleotide polymorphisms (SNPs) associated with spawning characteristics and salinity preferences would be an effective discrimination tool. The overall observed levels of genetic differentiation were high (FST = 0.57, p <0.001, 95% CI: 0.51-0.62). Spawners from stocks under current management (NSSH, NSAH and ISSH) were well separated, but the putative populations were not. Discriminant analysis of principal component as well as Structure runs confirmed the differentiation observed with FST. When the SNP panels were tested on commercial fishery samples of NSSH east of Iceland, up to 16% were assigned to ISSH. This implies that catch data are seriously biased and demonstrates the potential of SNP panels as a tool to solve the problem. However, work is needed to develop improved SNP panels that effectively separate the putative populations from the managed stocks. We recommend that such a tool should be established in regular sampling of fishery and surveys in the Norwegian Sea and accounted for in future stock assessments, advice and management.
摘要：在挪威海觅食的大西洋鲱鱼（Clupea harengus）假定由挪威春季产卵者（NSSH）、冰岛夏季产卵者（ISSH）和北海秋季产卵者（NSAH）组成。假定的挪威秋季产卵者（NASH）、法罗群岛秋季产卵者（FASH）和春季产卵者（FSSH）也在该地区觅食。然而，在找到区分混合样本中不同种群的方法之前，挪威海的渔业和调查数据将完全归因于占主导地位的NSSH，最终导致种群评估出现偏差。因此，我们评估了与产卵特征和盐度偏好相关的 120 个单核苷酸多态性（SNPs）是否是一种有效的区分工具。观察到的总体遗传分化水平较高（FST = 0.57，p <0.001，95% CI：0.51-0.62）。目前管理下的种群（NSSH、NSAH 和 ISSH）的产卵者分离得很好，但推定种群则不然。主成分和结构运行的判别分析证实了通过 FST 观察到的区分。在对冰岛以东的 NSSH 商业渔业样本进行 SNP 面板测试时，高达 16% 的样本被归入 ISSH。这意味着渔获量数据存在严重偏差，并证明了 SNP 面板作为解决这一问题的工具的潜力。不过，还需要努力开发改进的 SNP 面板，以有效区分假定种群与管理种群。我们建议在挪威海的定期渔业采样和调查中建立这样的工具，并在未来的种群评估、建议和管理中加以考虑。
{"title":"Discriminating populations of Atlantic herring mixing in the Norwegian Sea feeding ground using single nucleotide polymorphisms (SNPs)","authors":"Christophe Pampoulie, Aril Slotte, Guðmundur J. Óskarsson, Guðbjörg Ólafsdóttir, Jan Arge Jacobsen, Hóraldur Joensen, Sindri Karl Sigurðsson, Sæmundur Sveinsson, Leif Andersson, Anna Kristin Daníelsdóttir, Davíð Gíslason","doi":"10.3354/meps14619","DOIUrl":"https://doi.org/10.3354/meps14619","url":null,"abstract":"ABSTRACT: Atlantic herring <i>Clupea harengus</i> feeding in the Norwegian Sea are assumed to consist of Norwegian spring spawners (NSSH), Icelandic summer spawners (ISSH) and North Sea autumn spawners (NSAH). Putative Norwegian autumn spawners (NASH), Faroese autumn (FASH) and spring (FSSH) spawners also feed in the area. However, until there is a method to discriminate between populations in mixed samples, fishery and survey data from the Norwegian Sea will be solely attributed to the predominating NSSH, ultimately causing biased stock assessments. Hence, we evaluated if a panel of 120 single nucleotide polymorphisms (SNPs) associated with spawning characteristics and salinity preferences would be an effective discrimination tool. The overall observed levels of genetic differentiation were high (<i>F</i><sub>ST</sub> = 0.57, p <0.001, 95% CI: 0.51-0.62). Spawners from stocks under current management (NSSH, NSAH and ISSH) were well separated, but the putative populations were not. Discriminant analysis of principal component as well as Structure runs confirmed the differentiation observed with <i>F</i><sub>ST</sub>. When the SNP panels were tested on commercial fishery samples of NSSH east of Iceland, up to 16% were assigned to ISSH. This implies that catch data are seriously biased and demonstrates the potential of SNP panels as a tool to solve the problem. However, work is needed to develop improved SNP panels that effectively separate the putative populations from the managed stocks. We recommend that such a tool should be established in regular sampling of fishery and surveys in the Norwegian Sea and accounted for in future stock assessments, advice and management.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"111 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141785111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Morten D. Skogen, Johanna M. Aarflot, Luz María García-García, Rubao Ji, Manuel Ruiz-Villarreal, Elin Almroth-Rosell, Andrea Belgrano, Déborah Benkort, Ute Daewel, Moa Edman, René Friedland, Shuang Gao, Mariana Hill-Cruz, Solfrid Sætre Hjøllo, Martin Huret, Julie B. Kellner, Sonja van Leeuwen, Ane Lopez de Gamiz-Zearra, Marie Maar, Erik Askov Mousing, Myron A. Peck, Ane Pastor Rollan, Sévrine F. Sailley, Sofia Saraiva, Cassie Speakman, Tineke Troost, Veli Çağlar Yumruktepe
ABSTRACT: Our understanding of complex marine ecosystem dynamics is often hindered by significant uncertainties and issues of representativeness associated with models and observations. Both observations and models provide a limited view of real-world complexities depending on what is specifically measured or simulated. When used together, they provide the ability to gain a broader understanding of important ecological processes. How to properly integrate models and observations while utilizing the advantages of both approaches remains a challenge. In this paper, we draw attention to commonly overlooked limitations of both observations and models, and use examples to illustrate potential strategies to mitigate bias, properly interpret results, and help improve both models and observations. We emphasize that proper validation of all data sources (models and observations) is necessary in all marine ecosystem studies, with a careful assessment of the spatio-temporal scales that the data represent.
{"title":"Bridging the gap: integrating models and observations for better ecosystem understanding","authors":"Morten D. Skogen, Johanna M. Aarflot, Luz María García-García, Rubao Ji, Manuel Ruiz-Villarreal, Elin Almroth-Rosell, Andrea Belgrano, Déborah Benkort, Ute Daewel, Moa Edman, René Friedland, Shuang Gao, Mariana Hill-Cruz, Solfrid Sætre Hjøllo, Martin Huret, Julie B. Kellner, Sonja van Leeuwen, Ane Lopez de Gamiz-Zearra, Marie Maar, Erik Askov Mousing, Myron A. Peck, Ane Pastor Rollan, Sévrine F. Sailley, Sofia Saraiva, Cassie Speakman, Tineke Troost, Veli Çağlar Yumruktepe","doi":"10.3354/meps14616","DOIUrl":"https://doi.org/10.3354/meps14616","url":null,"abstract":"ABSTRACT: Our understanding of complex marine ecosystem dynamics is often hindered by significant uncertainties and issues of representativeness associated with models and observations. Both observations and models provide a limited view of real-world complexities depending on what is specifically measured or simulated. When used together, they provide the ability to gain a broader understanding of important ecological processes. How to properly integrate models and observations while utilizing the advantages of both approaches remains a challenge. In this paper, we draw attention to commonly overlooked limitations of both observations and models, and use examples to illustrate potential strategies to mitigate bias, properly interpret results, and help improve both models and observations. We emphasize that proper validation of all data sources (models and observations) is necessary in all marine ecosystem studies, with a careful assessment of the spatio-temporal scales that the data represent.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"47 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141786139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Emily S. Runnells, William A. Montevecchi, Gail K. Davoren
ABSTRACT: Little is known about the spatial and dietary overlap of seabird species during the non-breeding season, when scarce and patchy marine food resources could lead to interspecific competition. We aimed to quantify spatiotemporal and isotopic niche overlap among common murres Uria aalge, razorbills Alca torda, and Atlantic puffins Fratercula arctica outside the breeding season by combining data from geolocators and stable isotope ratios (δ15N, δ13C) of belly, secondary, and head feathers collected in 2017-2020 from birds breeding in coastal northeastern Newfoundland, Canada. Seasonal utilization distributions of each species indicated generally low spatial overlap during most of the non-breeding period, with exceptions immediately post-breeding and with variability in movement paths among puffins. Stable isotope analysis revealed a broader isotopic niche (1.5 to 3×) for puffins than other species, matching their greater spatial variation. There was no isotopic niche overlap among the 3 species, except during flight feather molt of razorbills and murres. Individual puffins located in the same area as razorbills or murres had lower δ15N values, suggesting a lower trophic position. The minimal overlap of these 3 alcid species during an understudied phase of their annual cycle suggests that they segregate spatially and partition resources, implying that different spatial planning and ecosystem conservation strategies should be applied to each of these 3 species.
{"title":"Spatiotemporal and isotopic niche overlap among Atlantic puffins, razorbills, and common murres during the non-breeding season in the Northwest Atlantic","authors":"Emily S. Runnells, William A. Montevecchi, Gail K. Davoren","doi":"10.3354/meps14614","DOIUrl":"https://doi.org/10.3354/meps14614","url":null,"abstract":"ABSTRACT: Little is known about the spatial and dietary overlap of seabird species during the non-breeding season, when scarce and patchy marine food resources could lead to interspecific competition. We aimed to quantify spatiotemporal and isotopic niche overlap among common murres <i>Uria aalge</i>, razorbills <i>Alca torda</i>, and Atlantic puffins <i>Fratercula arctica</i> outside the breeding season by combining data from geolocators and stable isotope ratios (δ<sup>15</sup>N, δ<sup>13</sup>C) of belly, secondary, and head feathers collected in 2017-2020 from birds breeding in coastal northeastern Newfoundland, Canada. Seasonal utilization distributions of each species indicated generally low spatial overlap during most of the non-breeding period, with exceptions immediately post-breeding and with variability in movement paths among puffins. Stable isotope analysis revealed a broader isotopic niche (1.5 to 3×) for puffins than other species, matching their greater spatial variation. There was no isotopic niche overlap among the 3 species, except during flight feather molt of razorbills and murres. Individual puffins located in the same area as razorbills or murres had lower δ<sup>15</sup>N values, suggesting a lower trophic position. The minimal overlap of these 3 alcid species during an understudied phase of their annual cycle suggests that they segregate spatially and partition resources, implying that different spatial planning and ecosystem conservation strategies should be applied to each of these 3 species.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"32 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141785038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kim E. Ludwig, Anja Singer, Ingrid Kröncke, Anne F. Sell
ABSTRACT: In marine ecosystems under ongoing long-term changes, reducing complex food webs to their functionally important properties enables systematic analysis of bottom-up/top-down regulations and species turnover. The assessment of feeding interactions in the form of predator and prey trait associations provides a better understanding of predators’ criteria for prey selection and thus is a promising approach to reduce complexity. Here, we tested RLQ ordination and fourth-corner analysis, complementary multivariate approaches, as tools to identify ecologically relevant associations between the traits of 8 demersal fish species in the southern North Sea and their fish or benthic prey. To scrutinize the trait-based results in their appropriateness to reflect selective feeding behaviour of the predator species, we compared them with a taxon-based electivity index, Chesson’s α. Among 7 predator traits investigated, body tissue composition represented by omega-3 polyunsaturated fatty acid content was significantly associated with prey traits, being positively correlated with energy density of the prey and negatively with prey of low mobility. Comparisons with the electivity indices showed that the prey preferred by predators corresponded relatively well with the identified prey trait preferences. The results of the tested analysis approach support its use when assessing the mutual dependences of predator and prey populations on a functional level. Provided the data availability and quality of feeding-related traits is sufficiently high, trait-based predator-prey analysis with RLQ and fourth-corner analyses offers new possibilities for understanding food web dynamics in the context of climate-change-induced species distribution shifts.
{"title":"Predator-prey trait associations and feeding preferences of demersal fishes in the southern North Sea","authors":"Kim E. Ludwig, Anja Singer, Ingrid Kröncke, Anne F. Sell","doi":"10.3354/meps14597","DOIUrl":"https://doi.org/10.3354/meps14597","url":null,"abstract":"ABSTRACT: In marine ecosystems under ongoing long-term changes, reducing complex food webs to their functionally important properties enables systematic analysis of bottom-up/top-down regulations and species turnover. The assessment of feeding interactions in the form of predator and prey trait associations provides a better understanding of predators’ criteria for prey selection and thus is a promising approach to reduce complexity. Here, we tested RLQ ordination and fourth-corner analysis, complementary multivariate approaches, as tools to identify ecologically relevant associations between the traits of 8 demersal fish species in the southern North Sea and their fish or benthic prey. To scrutinize the trait-based results in their appropriateness to reflect selective feeding behaviour of the predator species, we compared them with a taxon-based electivity index, Chesson’s α. Among 7 predator traits investigated, body tissue composition represented by omega-3 polyunsaturated fatty acid content was significantly associated with prey traits, being positively correlated with energy density of the prey and negatively with prey of low mobility. Comparisons with the electivity indices showed that the prey preferred by predators corresponded relatively well with the identified prey trait preferences. The results of the tested analysis approach support its use when assessing the mutual dependences of predator and prey populations on a functional level. Provided the data availability and quality of feeding-related traits is sufficiently high, trait-based predator-prey analysis with RLQ and fourth-corner analyses offers new possibilities for understanding food web dynamics in the context of climate-change-induced species distribution shifts.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"26 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141785041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Camila R. Barreto, Juan P. Quimbayo, Thiago C. Mendes, Cesar A. M. M. Cordeiro, Augusto A. V. Flores
ABSTRACT: Top-down and bottom-up processes can mediate the structuring of biological communities. Several studies have provided separate support for those processes in pelagic and benthic compartments of reef systems but studies focusing on whole-reef processes are less common. Here, we sampled 3 ‘reef compartments’ in the Alcatrazes Archipelago in Southeastern Brazil: benthic cover of colonial organisms, solitary organisms, and reef fish (i.e. pelagic) to identify the groups responsible for spatial community structure among reefs. A dynamic mosaic structure best defines the assemblages of each compartment, with substantial changes observed among sites over 2 consecutive years and at 2 depth strata, separated by a sharp thermocline. Changes in benthic cover of colonial organisms are largely due to the extent of the blooming of Sargassum canopies, algal turfs, and the zoanthid Palythoa caribaeorum. Solitary organisms show a consistent monotonic change in the abundance of sea urchins, ascidians, and snails. Fish assemblage structure differed among reefs; however, we observed that large invertivore fish tended to concentrate in warmer water above the thermocline and small fish of different feeding habits were found in deeper and colder water in all reefs. We observed a potential strong link between the reefscape and solitary organisms, with a negative relationship between the abundance of urchins and the cover of Sargassum spp. suggesting top-down control. A second link is indicated by a positive relationship between low-lying cover composed of articulated turf and P. caribaeorum and larger invertivorous fish, suggesting bottom-up control through the provision of favorable foraging grounds.
{"title":"Spatial structure and potential processes linking fish and benthic communities in a protected reef ecosystem in SE Brazil","authors":"Camila R. Barreto, Juan P. Quimbayo, Thiago C. Mendes, Cesar A. M. M. Cordeiro, Augusto A. V. Flores","doi":"10.3354/meps14589","DOIUrl":"https://doi.org/10.3354/meps14589","url":null,"abstract":"ABSTRACT: Top-down and bottom-up processes can mediate the structuring of biological communities. Several studies have provided separate support for those processes in pelagic and benthic compartments of reef systems but studies focusing on whole-reef processes are less common. Here, we sampled 3 ‘reef compartments’ in the Alcatrazes Archipelago in Southeastern Brazil: benthic cover of colonial organisms, solitary organisms, and reef fish (i.e. pelagic) to identify the groups responsible for spatial community structure among reefs. A dynamic mosaic structure best defines the assemblages of each compartment, with substantial changes observed among sites over 2 consecutive years and at 2 depth strata, separated by a sharp thermocline. Changes in benthic cover of colonial organisms are largely due to the extent of the blooming of <i>Sargassum</i> canopies, algal turfs, and the zoanthid <i>Palythoa caribaeorum</i>. Solitary organisms show a consistent monotonic change in the abundance of sea urchins, ascidians, and snails. Fish assemblage structure differed among reefs; however, we observed that large invertivore fish tended to concentrate in warmer water above the thermocline and small fish of different feeding habits were found in deeper and colder water in all reefs. We observed a potential strong link between the reefscape and solitary organisms, with a negative relationship between the abundance of urchins and the cover of <i>Sargassum</i> spp. suggesting top-down control. A second link is indicated by a positive relationship between low-lying cover composed of articulated turf and <i>P. caribaeorum</i> and larger invertivorous fish, suggesting bottom-up control through the provision of favorable foraging grounds.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"184 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141521388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT: Although knowledge of sandy beaches has increased recently, the benthic diversity of macrotidal sandy beaches in the northeastern Atlantic Ocean (more specifically, the western Channel and the northern Bay of Biscay) is poorly known. Here, we present a regional-scale account of the species diversity, both observed and estimated, of the macrobenthic fauna of Brittany based on an analysis of a species-level data set from 18 sandy beaches in Brittany that were sampled annually for 13 yr on the lower shore. In total, 526 species were identified, including 210 Annelida, 167 Arthropoda, 103 Mollusca, 19 Echinodermata and 27 species of other phyla. Four distinct habitats were distinguished based on their benthic communities and characterised using environmental variables. Sediment heterogeneity appeared to enhance diversity, as heterogeneous muddy sand harboured significantly more species than (muddy) fine sand. The role of environmental variables as structuring factors of benthic communities was investigated using redundancy analysis and variance partitioning. Beach morphodynamics and sediment structure explained most diversity variations (25.40 and 24.91%, respectively) followed by wave characteristics (13.46%). Finally, we offer some habitat-specific reference values regarding species richness and the Shannon index for M-AMBI computation during Water Framework Directive and Marine Strategy Directive evaluations for a more reliable characterisation of the ecological status of sandy beaches.
{"title":"Patterns in macrobenthic diversity in the lower shore of northeastern Atlantic macrotidal sandy beaches","authors":"Adeline Tauran, Nolwenn Quillien, Jacques Grall","doi":"10.3354/meps14599","DOIUrl":"https://doi.org/10.3354/meps14599","url":null,"abstract":"ABSTRACT: Although knowledge of sandy beaches has increased recently, the benthic diversity of macrotidal sandy beaches in the northeastern Atlantic Ocean (more specifically, the western Channel and the northern Bay of Biscay) is poorly known. Here, we present a regional-scale account of the species diversity, both observed and estimated, of the macrobenthic fauna of Brittany based on an analysis of a species-level data set from 18 sandy beaches in Brittany that were sampled annually for 13 yr on the lower shore. In total, 526 species were identified, including 210 Annelida, 167 Arthropoda, 103 Mollusca, 19 Echinodermata and 27 species of other phyla. Four distinct habitats were distinguished based on their benthic communities and characterised using environmental variables. Sediment heterogeneity appeared to enhance diversity, as heterogeneous muddy sand harboured significantly more species than (muddy) fine sand. The role of environmental variables as structuring factors of benthic communities was investigated using redundancy analysis and variance partitioning. Beach morphodynamics and sediment structure explained most diversity variations (25.40 and 24.91%, respectively) followed by wave characteristics (13.46%). Finally, we offer some habitat-specific reference values regarding species richness and the Shannon index for M-AMBI computation during Water Framework Directive and Marine Strategy Directive evaluations for a more reliable characterisation of the ecological status of sandy beaches.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"50 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141521389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT: Stable carbon (δ13C) and nitrogen (δ15N) isotope ratios are widely used in marine food web and habitat use studies. However, lipids are naturally depleted in 13C relative to proteins and are variable in content, biasing δ13C of bulk samples, with consequences for the accuracy of conclusions. This issue can be resolved either by extracting lipids from samples prior to analysis, a resource-intensive process that can also alter δ15N, or by estimating lipid-free δ13C using one of several equations that differ in degree of sophistication and generalization across taxa. Here, δ13C and δ15N were measured in bulk and lipid-extracted muscle samples from over 2000 specimens of 28 species of marine invertebrates, fishes, and mammals. Our objectives were to compare the effect of lipid extraction on δ13C and δ15N across taxa and evaluate the performance of 5 normalization models, overall and using subsets of species, to propose a model to revert lipid-extracted δ15N back to their bulk values and to identify the best approach for dealing with lipid-related biases. Lipid extraction caused an uneven enrichment in δ13C and δ15N across species. Model taxonomic specificity increased estimation accuracy for both isotopes. While models from Logan et al. (2008; J Anim Ecol 77:838-846) and McConnaughey & McRoy (1979; Mar Biol 53:257-262) were the best at predicting lipid-free δ13C, a linear model reliably estimated δ15N values of lipid-free samples using δ15N values of bulk samples. This study presents a method for reliably estimating δ13C and δ15N values of muscle tissue without resorting to duplicate analyses. This represents a major step toward the harmonization of data sets generated using bulk and lipid-extracted samples.
{"title":"Dealing with biases introduced by lipids in stable carbon and nitrogen isotope analyses: a solution based on 28 marine invertebrate, fish, and mammal species","authors":"Jean-François Ouellet, Jory Cabrol, Ève Rioux, Xavier Bordeleau, Véronique Lesage","doi":"10.3354/meps14595","DOIUrl":"https://doi.org/10.3354/meps14595","url":null,"abstract":"ABSTRACT: Stable carbon (δ<sup>13</sup>C) and nitrogen (δ<sup>15</sup>N) isotope ratios are widely used in marine food web and habitat use studies. However, lipids are naturally depleted in <sup>13</sup>C relative to proteins and are variable in content, biasing δ<sup>13</sup>C of bulk samples, with consequences for the accuracy of conclusions. This issue can be resolved either by extracting lipids from samples prior to analysis, a resource-intensive process that can also alter δ<sup>15</sup>N, or by estimating lipid-free δ<sup>13</sup>C using one of several equations that differ in degree of sophistication and generalization across taxa. Here, δ<sup>13</sup>C and δ<sup>15</sup>N were measured in bulk and lipid-extracted muscle samples from over 2000 specimens of 28 species of marine invertebrates, fishes, and mammals. Our objectives were to compare the effect of lipid extraction on δ<sup>13</sup>C and δ<sup>15</sup>N across taxa and evaluate the performance of 5 normalization models, overall and using subsets of species, to propose a model to revert lipid-extracted δ<sup>15</sup>N back to their bulk values and to identify the best approach for dealing with lipid-related biases. Lipid extraction caused an uneven enrichment in δ<sup>13</sup>C and δ<sup>15</sup>N across species. Model taxonomic specificity increased estimation accuracy for both isotopes. While models from Logan et al. (2008; J Anim Ecol 77:838-846) and McConnaughey & McRoy (1979; Mar Biol 53:257-262) were the best at predicting lipid-free δ<sup>13</sup>C, a linear model reliably estimated δ<sup>15</sup>N values of lipid-free samples using δ<sup>15</sup>N values of bulk samples. This study presents a method for reliably estimating δ<sup>13</sup>C and δ<sup>15</sup>N values of muscle tissue without resorting to duplicate analyses. This represents a major step toward the harmonization of data sets generated using bulk and lipid-extracted samples.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"154 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141531595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Andre Buchheister, Paul McElhany, Eric P. Bjorkstedt
ABSTRACT: Ocean acidification (OA) and ocean warming driven by climate change are important stressors for marine species and systems, but documenting and detecting their long-term impacts on biological responses outside of laboratory settings are challenging due to natural variability caused by complex processes and interactions. We used settlement of purple sea urchins Strongylocentrotus purpuratus in the Southern California Bight (USA) over 6 yr as an example data set to parameterize a simulation model for exploring the time needed to detect environmental effects on a biological response. A generalized linear model was used to describe an index of urchin settlement as functions of pH, sea surface temperature (SST), sea surface salinity (SSS), and spatio-temporal factors, demonstrating that settlement was negatively associated with pH (i.e. lower settlement at higher pH) and positively associated with SST and SSS. Monte Carlo simulations were developed from this base model under a variety of alternative scenarios to estimate the time to detect: (1) annual trends in pH and SST time series, (2) pH and SST effects on urchin settlement, and (3) annual trends in urchin settlement. Time to detect pH and SST effects was predominantly influenced by the underlying strength of the relationships and the model uncertainty. Time to detect annual trends in settlement was more sensitive to the severity of long-term OA and warming trends, which had cumulative (at times opposing) effects. This study highlights the variable time scales (2-60+ yr) that may be necessary to detect biological responses to OA and ocean warming and the sensitivity to different assumptions of the study system.
{"title":"Evaluating the time to detect biological effects of ocean acidification and warming: an example using simulations of purple sea urchin settlement","authors":"Andre Buchheister, Paul McElhany, Eric P. Bjorkstedt","doi":"10.3354/meps14598","DOIUrl":"https://doi.org/10.3354/meps14598","url":null,"abstract":"ABSTRACT: Ocean acidification (OA) and ocean warming driven by climate change are important stressors for marine species and systems, but documenting and detecting their long-term impacts on biological responses outside of laboratory settings are challenging due to natural variability caused by complex processes and interactions. We used settlement of purple sea urchins <i>Strongylocentrotus purpuratus</i> in the Southern California Bight (USA) over 6 yr as an example data set to parameterize a simulation model for exploring the time needed to detect environmental effects on a biological response. A generalized linear model was used to describe an index of urchin settlement as functions of pH, sea surface temperature (SST), sea surface salinity (SSS), and spatio-temporal factors, demonstrating that settlement was negatively associated with pH (i.e. lower settlement at higher pH) and positively associated with SST and SSS. Monte Carlo simulations were developed from this base model under a variety of alternative scenarios to estimate the time to detect: (1) annual trends in pH and SST time series, (2) pH and SST effects on urchin settlement, and (3) annual trends in urchin settlement. Time to detect pH and SST effects was predominantly influenced by the underlying strength of the relationships and the model uncertainty. Time to detect annual trends in settlement was more sensitive to the severity of long-term OA and warming trends, which had cumulative (at times opposing) effects. This study highlights the variable time scales (2-60+ yr) that may be necessary to detect biological responses to OA and ocean warming and the sensitivity to different assumptions of the study system.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"47 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141531596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Briggs, J. Alfaro-Shigueto, J. C. Mangel, Nicolas Acuña-Perales, Sergio Pingo, Astrid Jimenez, A. F. Johnson
ABSTRACT: The post-capture movements made by hawksbill sea turtles Eretmochelys imbricata in the southeast Pacific Ocean were monitored between 2014 and 2017. A total of 8 hawksbill turtles were fitted with satellite transmitters and released in Sechura Bay, northern Peru. All turtles were classified as juveniles (curved carapace length range: 34.7-47.5 cm) and were captured in a small-scale demersal set net fishery in Sechura Bay. Track durations ranged from 9 to 489 d. Six of the 8 turtles remained within the bay for the duration of their tracking, suggesting its importance as a long-term juvenile foraging site. Two turtles departed the bay and travelled over 1000 km, passing the Galapagos Islands, Ecuador. The satellite tracks of those turtles that remained within the bay showed a significant overlap with areas used by the demersal set net fishery operating there (mean overlap: 33%). The long residence times and high affinity for coastal areas observed in these tagged individuals make the turtles susceptible to multiple threats within the bay, including interactions with intensive small-scale fishing from the ports of Parachique, Puerto Rico, and Bayovar, as well as pollution and contamination from the communities that encompass the bay. More comprehensive measures are needed to quantify and characterize the threats faced by this endangered species in this unique habitat and to recommend practical conservation actions.
{"title":"Juvenile hawksbill turtle Eretmochelys imbricata movement patterns in Sechura Bay, Peru, assessed with satellite tracking","authors":"M. Briggs, J. Alfaro-Shigueto, J. C. Mangel, Nicolas Acuña-Perales, Sergio Pingo, Astrid Jimenez, A. F. Johnson","doi":"10.3354/meps14604","DOIUrl":"https://doi.org/10.3354/meps14604","url":null,"abstract":"ABSTRACT: The post-capture movements made by hawksbill sea turtles <i>Eretmochelys imbricata</i> in the southeast Pacific Ocean were monitored between 2014 and 2017. A total of 8 hawksbill turtles were fitted with satellite transmitters and released in Sechura Bay, northern Peru. All turtles were classified as juveniles (curved carapace length range: 34.7-47.5 cm) and were captured in a small-scale demersal set net fishery in Sechura Bay. Track durations ranged from 9 to 489 d. Six of the 8 turtles remained within the bay for the duration of their tracking, suggesting its importance as a long-term juvenile foraging site. Two turtles departed the bay and travelled over 1000 km, passing the Galapagos Islands, Ecuador. The satellite tracks of those turtles that remained within the bay showed a significant overlap with areas used by the demersal set net fishery operating there (mean overlap: 33%). The long residence times and high affinity for coastal areas observed in these tagged individuals make the turtles susceptible to multiple threats within the bay, including interactions with intensive small-scale fishing from the ports of Parachique, Puerto Rico, and Bayovar, as well as pollution and contamination from the communities that encompass the bay. More comprehensive measures are needed to quantify and characterize the threats faced by this endangered species in this unique habitat and to recommend practical conservation actions.","PeriodicalId":18193,"journal":{"name":"Marine Ecology Progress Series","volume":"49 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141528946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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