Marine Community Ecology

An error occurred in article "Technical mitigation measures for sharks and rays in fisheries for tuna and tuna-like species: turning possibility into reality" published in Volume 29, 402 (2016). The first name and last name of the author "Pascal Bach" were reversed in previous version. This correction notice provides the correct online file. Publisher apologizes for the inconvenience.

Knowledge of the ecology of the fish fauna associated with kelp (primarily Macrocystis pyrifera) forests in Southern Patagonia is scarce, especially in how abiotic and biotic variables influence their structure, diversity, and distribution. This information is important for the management and conservation of this unique ecosystem, which has minimal anthropogenic impacts at present. We analyzed data from 122 quantitative underwater transects conducted within kelp forests at 61 stations from Chile’s southern Patagonian fjords to the Cape Horn and Diego Ramirez archipelagos and the southern tip of Argentina, including the Mitre Peninsula and Isla de los Estados. In total, 25 fish species belonging to 13 families were observed. Multivariate analysis indicated that there are significant differences in fish assemblage structure among locations and wave exposures, which was driven primarily by Patagonotothen sima and Paranotothenia magellanica, which occurred on exposed and semi-exposed st...

Publicación online disponible en: http://www.icm.csic.es/scimar/index.php[EN] Erosion problems in coastal zones are increasingly threatening Mediterranean shores. In tourist areas such as the Catalan coast, there has been an increasing demand for the construction of low crested structures (LCS) to maintain beaches for recreational purposes. We studied the composition of the biota from three LCS and compared it with that of nearby natural rocky shores. Our purpose was to assess the composition of the communities growing on the LCS at a regional scale and to explore potential patterns of community composition in LCS in relation to the nature of the surrounding coast (i.e. sand or rocky shore), distance from natural hard-bottom communities and orientation of the blocks within the structure. The communities growing on the LCS were similar to those from nearby natural shores but the diversity and the number of taxa was always lower. Sixty to 95% of the species present on natural rocky sh...

Polyplacophorans are common herbivores on rocky shores, but basic aspects of their ecology remain scarcely studied and their role within communities could be more complex than previously considered. Such is the case of Acanthopleura echinata (Barnes), one of the largest and most conspicuous chitons in the world, and at the same time, one of the least known intertidal species in the southeastern Pacifi c. To improve the basic ecological knowledge of this potentially important intertidal consumer, we studied the diet of A. echinata and its variation among sites of varying levels of coastal upwelling spread over 1000 km along the coast of northern Chile. A seasonal evaluation of diet, body size distribution and density at sites expected to vary in overall nutrient loadings, benthic algal productivity and sea surface temperature, allowed us to examine plasticity in Acantholeura diet and body size. Overall, A. echinata consumed 85 items of algae (64.7 %, mainly fl eshy and calcifi ed encrusting thalli) and invertebrates (35.3 %, mainly barnacles). Diet was always dominated by encrusting corallines, although the proportion of algae increased with body size suggesting an ontogenetic variation in feeding habits. Although the number and occurrence frequency of dietary items varied signifi cantly in time and space, there were no consistent seasonal patterns and the dominant items in the diet remained the same at all places. The density of A. echinata showed no signifi cant spatial variation, but its body size and diet breadth correlated positively among sites and both tended to increase with latitude. Our results show that A. echinata is a generalist, polyphagous consumer with a high potential for affecting the space-occupancy dynamics in the intertidal system, and also that among site variation in diet bears no simple relationship with variation in sea surface temperature and upwelling intensity.

The biotope approach developed originally for use in Northern Europe has been used to describe and classify benthic marine assemblages in various parts o f the world, including the Laguna San Rafael National Park (LSRNP) in southern Chile and nearby protected areas. Given is a brief description o f how to identify, describe, classify and map marine biotopes. Some o f the more widely distributed rocky shore biotopes in the LSRNP area are briefly described. Full biotope descriptions are given for the most distinctive biotope within the fjords (Macrocystis pyrifera biotope) and two on the very wave-exposed open Pacific coast (Durvillaea antarctica, Lessonia nigrescens). All the biotopes recognised are regarded as provisional and require further testing and refinement. Once refined biotopes can be taken into account when making management and conservation decisions on seashore and seabed habitats within the LSRNP and surrounding nature reserves.

Shin, Y-J., and Shannon, L. J. 2010. Using indicators for evaluating, comparing and communicating the ecological status of exploited marine ecosystems. 1. The IndiSeas project. – ICES Journal of Marine Science, 67: 686–691. One of the challenges faced by the scientific community grappling with the ecosystem approach to fisheries is to propose a generic set of synthetic ecological indicators, which would accurately reflect the effects of fisheries on marine ecosystems, and could support sound communication and management practices. The IndiSeas Working Group was established in 2005 under the auspices of the Eur-Oceans Network of Excellence to develop methods to provide indicators-based assessments of the status of exploited marine ecosystems in a comparative framework. Here, we present the two main outputs of the first phase of the project: a suite of papers documenting a combination of indicator-based methods and results comparing the ecological status of the world's exploited m...

Kelps provide important habitat for a range of species, however they are suffering increasing levels of degradation. This has prompted efforts to restore these ecosystems, however, the trajectory of community establishment on artificial reefs has not being widely described. We examined the composition of the species and functional groups of invertebrates and fish in relation to the artificial reefs over soft-bottom and barren-ground habitats over a 10-month period. We evaluated the community structure based on species richness, biomass, species diversity, and dominance of species and functional groups. We assessed the trajectories of the ecological succession of artificial reefs planted with kelp on each bottom type and determined the changes in the dissimilarity of species and functional groups over time. We also analysed the relationship between the biogeny (of macroalgae) over time (months) and the changes in macrobenthic community structure. Successional development of reefs communities was similar across the two habitat types, macroalgae contributed most to the early stage, while invertebrates and fish were the groups that contributed the most during the middle and late successional stages. A positive relationship was found between the presence of artificial reefs with kelp seedlings and the biomass of specific species and functional groups. This study showed that new kelp habitats promote the construction of biogenic structures that increase the habitat complexity, promote biodiversity, and increase populations of commercially harvested species. In this sense, artificial reefs should be considered an important tool for restoring the function of degraded benthic ecosystems.

Mediterranean coastal areas are threatened by coastal development that modifies the coastline through the construction of buildings and infrastructures such as roads, railways, promenades and ports. The main consequences of this development are changes in the deposition processes and wave regime that lead to increasing erosion. In addition, the sea-level rise and increasing storminess due to climate change may also contribute to beach recession and flooding in coastal areas. Along the Catalan coast, beach tourism is one of the main resources of the local economy, and there has SCIENTIA MARINA 71(2)

Polyplacophorans are common herbivores on rocky shores, but basic aspects of their ecology remain scarcely studied and their role within communities could be more complex than previously considered. Such is the case of Acanthopleura echinata (Barnes), one of the largest and most conspicuous chitons in the world, and at the same time, one of the least known intertidal species in the southeastern Pacifi c. To improve the basic ecological knowledge of this potentially important intertidal consumer, we studied the diet of A. echinata and its variation among sites of varying levels of coastal upwelling spread over 1000 km along the coast of northern Chile. A seasonal evaluation of diet, body size distribution and density at sites expected to vary in overall nutrient loadings, benthic algal productivity and sea surface temperature, allowed us to examine plasticity in Acantholeura diet and body size. Overall, A. echinata consumed 85 items of algae (64.7 %, mainly fl eshy and calcifi ed encrusting thalli) and invertebrates (35.3 %, mainly barnacles). Diet was always dominated by encrusting corallines, although the proportion of algae increased with body size suggesting an ontogenetic variation in feeding habits. Although the number and occurrence frequency of dietary items varied signifi cantly in time and space, there were no consistent seasonal patterns and the dominant items in the diet remained the same at all places. The density of A. echinata showed no signifi cant spatial variation, but its body size and diet breadth correlated positively among sites and both tended to increase with latitude. Our results show that A. echinata is a generalist, polyphagous consumer with a high potential for affecting the space-occupancy dynamics in the intertidal system, and also that among site variation in diet bears no simple relationship with variation in sea surface temperature and upwelling intensity.

The biotope approach developed originally for use in Northern Europe has been used to describe and classify benthic marine assemblages in various parts o f the world, including the Laguna San Rafael National Park (LSRNP) in southern Chile and nearby protected areas. Given is a brief description o f how to identify, describe, classify and map marine biotopes. Some o f the more widely distributed rocky shore biotopes in the LSRNP area are briefly described. Full biotope descriptions are given for the most distinctive biotope within the fjords (Macrocystis pyrifera biotope) and two on the very wave-exposed open Pacific coast (Durvillaea antarctica, Lessonia nigrescens). All the biotopes recognised are regarded as provisional and require further testing and refinement. Once refined biotopes can be taken into account when making management and conservation decisions on seashore and seabed habitats within the LSRNP and surrounding nature reserves.

Gettysburg and Ormonde are two shallow peaks located on the Gorringe seamount about 200 and 240 km WSW off Cape St. Vincent (Portugal, NE Atlantic), within the Portuguese Economic Exclusive Zone. Despite the ecological importance of the biological assemblages on these peaks and the need to preserve seamounts as valuable habitats, no management plans have been yet implemented at this site, which only recently has been included in the list of Sites of Community Importance of Portugal. Video imagery collected using a ROV during the 2011 Oceana campaigns was used here to analyse qualitative and quantitative patterns of benthic assemblage composition at the summit of the seamount (between 30 and 230 m depth). The results suggest that Ormonde is a biologically important area made up of vulnerable marine ecosystem elements that change significantly with depth. These include: kelp beds, in the euphotic zone; encrusting coralline algal communities and solitary colonies or mixed associations of suspension-feeders (scleractinians, gorgonians, antipatharians, encrusting demosponges and ascidians), at the lower limit of the euphotic zone; mixed coral gardens and erect sponges, in the disphotic zone; and dense sponge aggregations, on the upper slope. These results were further used to propose amendments to the European Nature Information System habitat classification as a tool to work towards resolving the seamounts management issue. The results also provide information on taxa and habitats with high ecological value and classified as threatened or vulnerable, which is essential for the implementation of the cornerstones of Europe's biodiversity conservation policy, namely the OSPAR Convention and the EU Habitats Directive.

Both local and global stressors threaten coral reefs, putting the food security, cultural continuity, and livelihoods of millions of reef-dependent people at risk. Still, scientists lack an understanding of how climate-driven heat stress interacts with local stressors such as fishing and pollution to influence reef health. Coral reef communities in the Marshall Islands and Kiribati, both low-lying atoll nations in the central Pacific, offer an opportunity to examine these interactions. The Gilbert Islands of Kiribati, which straddle the equator, experience highly variable sea surface temperatures (SSTs) inter-annually due to El Niño / Southern Oscillation, driving coral bleaching events in 2004/2005 and 2009/2010, while the Marshall Islands further north of the equator experience more stable SSTs. Both nations are home to degraded reefs near their capitol atolls, which host over half of each country’s populations. I first analyzed the benthic trajectories of coral reefs in the Gilbert Islands from 2012, 2014, 2016, and 2018, across a gradient of local human disturbance after multiple stressors, including two heat stress events and an outbreak of the corallivorous Crown-of-Thorns (CoTs) starfish, finding that locally degraded reefs were more resistant to heat stress than less trafficked reefs because the former were home to hardier taxa. Next, comparing locally disturbed and undisturbed reefs in Kiribati to those in the Marshalls demonstrated that the interactions between local and global stressors were context-dependent; the taxa that were present dictated the interactions. Then, via a meta-analysis of 1,205 sites in the Indian and Pacific Oceans, I demonstrated that a proxy often used to assess the effects of local human disturbance on reef health, the percent cover of macroalgae, does not correlate with local human disturbance. Instead, different genera of macroalgae exhibited diverse and often opposing responses to various sources of local human disturbance. Finally, I used public archives from an email listserv popular among the coral conservation community to analyze the policy narratives used by participants when discussing local threats to reefs, the actors involved in the local threat, their distal drivers, and the proposed solutions, revealing underlying assumptions about reefs and local people, which could inadvertently undermine conservation.

This report summarizes the outcomes of an IndiSeas workshop aimed at using ecosystem indicators to evaluate the status of the world's exploited marine ecosystems in support of an ecosystem approach to fisheries, and global policy drivers such as the 2020 targets of the Convention on Biological Diversity. Key issues covered relate to the selection and integration of multidisciplinary indicators, including climate, biodiversity and human dimension indicators, and to the development of dataand model-based methods to test the performance of ecosystem indicators in providing support for fisheries management. To enhance the robustness of our crosssystem comparison, unprecedented effort was put in gathering regional experts from developed and developing countries, working together on multi-institutional survey datasets, and using the most up-to-date ecosystem models. Keywords Indicator Á Ecosystem approach to fisheries Á Ecosystem model Á Fisheries management Á Global comparison Please refer the ''Appendix'' section for the ''IndiSeas Working Group'' authors.

from the Harbor School also provided access to facilities and valuable feedback on the design and construction of surveying equipment. Thank you to volunteers Hillary Smith (fish food index), Alex Fox (fish food index), Dylan Adler (filming) and Colm Kelleher (Mathematica coding).

Integrating results from monitoring efforts conducted across diverse marine ecosystems provides opportunities to reveal novel biogeographic patterns at larger spatial scales and among multiple taxonomic groups. We investigated large-scale patterns of community similarity across major taxonomic groups (invertebrates, fishes or algae) from a range of marine ecosystems (rocky intertidal, sandy intertidal, kelp forest, shallow and deep soft-bottom subtidal) in southern California. Because monitoring sites

The reef crests of the Jardines de la Reina National Park are largely formed by Acropora palmata, but colonies of Acropora cervicornis and the hybrid Acropora prolifera are also present. This study shows spatial distribution of colonies, thickets and live fragments of these species in the fore reefs. Snorkeling was used to perform the direct observations. The maximum diameter of 4,399 colonies of A. palmata was measured and the health of 3,546 colonies was evaluated. The same was done to 168 colonies of A. cervicornis and 104 colonies of A. prolifera. The influence of the location and marine currents on a number of living colonies of A. palmata was analyzed. For such purpose, reef crests were divided into segments of 500 m. The marine park was divided into two sectors: East and West. The Caballones Channel was used as the reference dividing line. The park was also divided into five reserve zones. We counted 7,276 live colonies of Acropora spp. 1.4% was A. prolifera, 3.5% A. cervicor...

El caso particular de estudio corresponde al sitio Iglesia de Huanchaco, sector José Olaya. Las excavaciones realizadas durante los años 2017,2018,2019 y 2020 han demostrado una ocupación de características residenciales asociadas a ambientes y depósitos, así como también de carácter funerario con presencia de plataformas y cámaras funerarias de filiación Moche IV los cuales se superponen y disturban un anterior cementerio de filiación Virú. Finalmente se discutirá la presencia  Moche y su cronología en relación a su posible ocupación Tardía para este sector.

In a context of growing fishing pressures and recommendations for an ecosystem approach to fisheries, there is a need to monitor changes in fish communities over time. In this study, we analysed data from scientific trawl surveys carried out on the continental shelf off Guinea between 1985 and 2012. We performed factorial analyses and calculated biodiversity indices to characterise the changes in the structure and composition of fish communities that occurred over the 28-year period in this area, particularly given intensive fishing activities. We show that, over the study period, fish communities on the Guinean shelf were structured primarily according to spatial factors, with temporal changes being less pronounced than expected. However, a temporal analysis of biodiversity indices and species dominance showed that the intensification of fishing had significant effects on the general ecological features of the fish assemblages under study. There was a decrease in fish density and in mean trophic level. In addition, there were changes in species dominance, whereby large, slow-growing species with high commercial value were gradually replaced by smaller, fast-growing species of lesser commercial interest. These results from field observations are in line with some conclusions from previous modelling studies in the same geographical area, and provide further support for the hypothesis of a progressive 'ecosystem effect of fishing' occurring in Guinean waters.

Gaston, 2013). Particularly, urban infrastructure is often associated with enhanced thermal patterns, which can affect human health, and plant and animal distribution and abundance in terrestrial ecosystems (Larsen, 2015; Wilby & Perry, 2006). Thus, mapping the thermal mosaics found within urban environments such as cities and

Shin, Y-J., and Shannon, L. J. 2010. Using indicators for evaluating, comparing and communicating the ecological status of exploited marine ecosystems. 1. The IndiSeas project. – ICES Journal of Marine Science, 67: 686–691. One of the challenges faced by the scientific community grappling with the ecosystem approach to fisheries is to propose a generic set of synthetic ecological indicators, which would accurately reflect the effects of fisheries on marine ecosystems, and could support sound communication and management practices. The IndiSeas Working Group was established in 2005 under the auspices of the Eur-Oceans Network of Excellence to develop methods to provide indicators-based assessments of the status of exploited marine ecosystems in a comparative framework. Here, we present the two main outputs of the first phase of the project: a suite of papers documenting a combination of indicator-based methods and results comparing the ecological status of the world's exploited m...

IndiSeas ("Indicators for the Seas") is a collaborative international working group that was established in 2005 to evaluate the status of exploited marine ecosystems using a suite of indicators in a comparative framework. An initial shortlist of seven ecological indicators was selected to quantify the effects of fishing on the broader ecosystem using several criteria (i.e., ecological meaning, sensitivity to fishing, data availability, management objectives and public awareness). The suite comprised: (i) the inverse coefficient of variation of total biomass of surveyed species, (ii) mean fish length in the surveyed community, (iii) mean maximum life span of surveyed fish species, (iv) proportion of predatory fish in the surveyed community, (v) proportion of under and moderately exploited stocks, (vi) total biomass of surveyed species, and (vii) mean trophic level of the landed catch. In line with the Nagoya Strategic Plan of the Convention on Biological Diversity (2011-2020), we extended this suite to emphasize the broader biodiversity and conservation risks in exploited marine ecosystems. We selected a subset of indicators from a list of empirically based candidate biodiversity indicators initially established based on ecological significance to complement the original IndiSeas indicators. The additional selected indicators were: (viii) mean intrinsic vulnerability index of the fish landed catch, (ix) proportion of nondeclining exploited species in the surveyed community, (x) catch-based marine trophic index, and (xi) mean trophic level of the surveyed community. Despite the lack of data in some ecosystems, we also selected (xii) mean trophic level of the modelled community, and (xiii) proportion of discards in the fishery as extra indicators. These additional indicators were examined, along with the initial set of IndiSeas ecological indicators, to evaluate whether adding new biodiversity indicators provided useful additional information to refine our understanding of the status evaluation of 29 exploited marine ecosystems. We used state and trend analyses, and we performed correlation, redundancy and multivariate tests. Existing developments in ecosystem-based fisheries management have largely Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site. focused on exploited species. Our study, using mostly fisheries independent survey-based indicators, highlights that biodiversity and conservation-based indicators are complementary to ecological indicators of fishing pressure. Thus, they should be used to provide additional information to evaluate the overall impact of fishing on exploited marine ecosystems. ► We selected indicators to capture biodiversity and conservation risks in marine exploited ecosystems. ► We assessed if they provided useful additional information to refine the evaluation of marine exploited ecosystem status. ► We used state and trend analyses, performed correlation, redundancy and multivariate tests. ► Biodiversity and conservation-based indicators were complementary to evaluate the overall impact of fishing.

Ten years ago, we studied the distribution and status of Acropora palmata at archipelago Los Roques because the actual status of this species at Los Roques was unclear in this archipelago after its regional collapse. In that opportunity we aimed to produce a baseline study for this species in Los Roques combining population genetics with demographic data. At that time, our results suggested that this species had the potential to come back at least in 6 out of 10 surveyed sites. This conclusion was based upon high abundance, low disease prevalence, high genetic diversity and a dominance of sexual reproduction in these populations. However, we recognized that the potential of recovery could be hindered depending on local and regional threats. In 2014, the status of this species was re-evaluated by increasing the number of sites from 12 to 106 and by identifying and targeting local and global threats that may affect population recovery. The results from this new survey showed that A. p...

An error occurred in article "Technical mitigation measures for sharks and rays in fisheries for tuna and tuna-like species: turning possibility into reality" published in Volume 29, 402 (2016). The first name and last name of the author "Pascal Bach" were reversed in previous version. This correction notice provides the correct online file. Publisher apologizes for the inconvenience.

A first-ever effort to rank commercially-important mollusk species of Panay Island was conducted based on an extensive survey between March and April 2018. Ranking was based on the following criteria, namely: commercial value (40%), catch rates (20%), sources of threats (type of gear, processing plants, and number of fishers) (20%), frequency in the markets and source sites (10%), and literature available (10%), modified to a certain extent. A total of 90 mollusk species categorized into bivalves (49), gastropods (32), and cephalopods (9) were ranked. The comb pen shell Atrina pectinata (Pinnidae), Indian squid Uroteuthis duvaucelii (Loliginidae), and the scallop Mimachlamys sanguinea (formerly Chlamys senatoria) (Pectinidae) formed the top three species in the list strongly attributed to their high commercial value and thus catch rates. Squids, in general, are caught by trawls, whereas most of the other species are harvested primarily by gleaning and diving. The study highlights the high diversity of the malaco-fauna of Panay, as well as the multi-gear character of tropical fisheries. This ranked inventory can be used in prioritizing research on mollusks, by identifying target species for more in-depth studies useful for establishing their present status.

Background.Herbivores play a critical role in structuring benthic communities on tropical coral dominated reefs because they remove macro and microalgae, which might otherwise overgrow adult corals or prevent successful recruitment of juveniles. Reducing herbivory has been implicated in promoting phase shifts from coral dominance to other ecosystem states following acute disturbances. Turbidity and sedimentation are key physical processes that also structure coral reef communities because they limit light penetration and may interfere with biological processes such as heterotrophy. Singapore’s coral reefs have been heavily impacted by human activities for decades and experience very high levels of sedimentation and turbidity. Macroalgae, particularly Sargassum spp. are abundant on the reef flats, while adjacent reef slopes are dominated by diverse coral assemblages, yet nothing is known about the role of herbivory in structuring these heavily disturbed reefs. Methods. To gain a bett...

Herbivores play a critical role in structuring benthic communities on tropical coral dominated reefs by removing macroalgae. Reducing herbivory has been implicated in promoting phase shifts from coral dominance to other ecosystem states following disturbances. Turbidity and sedimentation are key physical processes that also structure coral reef communities because they limit light penetration and interfere with biological processes such as heterotrophy. Singapore’s coral reefs have been heavily impacted by human activities for decades and experience very high levels of sedimentation and turbidity. As a result, coral and algal growth is restricted to shallow reef flats and upper reef slopes. While macroalgae, particularly Sargassum spp., are abundant on the reef flats (0-2 m depth), adjacent upper reef slopes (3-4 m depth) are dominated by diverse hard coral assemblages composed primarily of sediment tolerant taxa. To gain a better understanding of the role of herbivore biomass and h...

A first-ever effort to rank commercially-important mollusk species of Panay Island was conducted based on an extensive survey between March and April 2018. Ranking was based on the following criteria, namely: commercial value (40%), catch rates (20%), sources of threats (type of gear, processing plants, and number of fishers) (20%), frequency in the markets and source sites (10%), and literature available (10%), modified to a certain extent. A total of 90 mollusk species categorized into bivalves (49), gastropods (32), and cephalopods (9) were ranked. The comb pen shell Atrina pectinata (Pinnidae), Indian squid Uroteuthis duvaucelii (Loliginidae), and the scallop Mimachlamys sanguinea (formerly Chlamys senatoria) (Pectinidae) formed the top three species in the list strongly attributed to their high commercial value and thus catch rates. Squids, in general, are caught by trawls, whereas most of the other species are harvested primarily by gleaning and diving. The study highlights the high diversity of the malaco-fauna of Panay, as well as the multi-gear character of tropical fisheries. This ranked inventory can be used in prioritizing research on mollusks, by identifying target species for more in-depth studies useful for establishing their present status.

Coral decline in the Caribbean is marked by the loss of habitat-forming corals, such as elkhorn coral (Acropora palmata). Elkhorn coral recovery has been isolated and patchy, but recently a "re-sheeting" phenomenon, in which elkhorn tissue grows over standing dead coral skeletons, was observed along the reefs in the Mexican Yucatán peninsula. Little is known about the ecological factors contributing to "re-sheeting," but it is hypothesized that grazing from herbivores provides top-down control of algal growth and promotes coral recovery. The purpose of this study was to evaluate the status of elkhorn populations in Akumal, Mexico and determine if Diadema urchins or parrotfish populations are associated with higher elkhorn abundance and lower algal cover. To achieve this objective, we surveyed 12 spur and groove reef sites in Akumal, where re-sheeting was recently observed, and measured elkhorn coral and herbivore population metrics. We found that both herbivore groups are associated with increasing elkhorn coral presence and cover, and lower macroalgal cover. Additionally, we tested for sampling bias in counting Diadema urchins and found that a significant difference in urchins counts between paired day and night transects on shallow, high complexity reefs. Our results suggest that historically important herbivore groups may be contributing to the recovery of elkhorn coral in Akumal by facilitating tissue re-sheeting.

Mass extinctions documented by the fossil record provide critical benchmarks for assessing changes through time in biodiversity and ecology. Efforts to compare biotic crises of the past and present, however, encounter difficulty because taxonomic and ecological changes are decoupled, and although various metrics exist for describing taxonomic turnover, no methods have yet been proposed to quantify the ecological impacts of extinction events. To address this issue, we apply a network-based approach to exploring the evolution of marine animal communities over the Phanerozoic Eon. Network analysis of fossil co-occurrence data enables us to identify nonrandom associations of interrelated paleocommunities. These associations, or evolutionary paleocommunities, dominated total diversity during successive intervals of relative community stasis. Community turnover occurred largely during mass extinctions and radiations, when ecological reorganization resulted in the decline of one associatio...

Mass extinctions documented by the fossil record provide critical benchmarks for assessing changes through time in biodiversity and ecology. Efforts to compare biotic crises of the past and present, however, encounter difficulty because taxonomic and ecological changes are decoupled, and although various metrics exist for describing taxonomic turnover, no methods have yet been proposed to quantify the ecological impacts of extinction events. To address this issue, we apply a network-based approach to exploring the evolution of marine animal communities over the Phanerozoic Eon. Network analysis of fossil co-occurrence data enables us to identify nonrandom associations of interrelated paleocommunities. These associations, or evolutionary paleocommunities, dominated total diversity during successive intervals of relative community stasis. Community turnover occurred largely during mass extinctions and radiations, when ecological reorganization resulted in the decline of one associatio...

This study summarises the diversity of living macroinvertebrates and seaweeds from the intertidal and subtidal rocky shores along Ecuadorian continental coast. Benthic macroinvertebrate communities and seaweeds were quantified over quadrants (50 × 50 cm) randomly placed on transects of 50 m length. A checklist of 612 species was generated: 479 species of macroinvertebrates and 133 species of seaweeds. Groups recorded were Mollusca (184 species), Cnidaria (70), Arthropoda (68), Annelida (60), Echinodermata (42), Chordata (18), Bryozoa (13), Porifera (22), Sipuncula (2), Brachiopoda and Platyhelminthes (only identified as morphotypes). The seaweeds were represented by Rhodophyta (78), Chlorophyta (37), Ochrophyta (13), Cyanobacteria (5) and 19 biotic complexes. Furthermore, 22 new taxa and six alien species were recorded from the intertidal zone. This study provides the first large scale report of benthic communities in different marine coastal ecosystems in mainland Ecuador, covering...

In the Aleutian Islands, Alaska, crustose coralline algae can be widespread in the low intertidal and shallow subtidal regions, and cover most available hard substrates. The longevity and slow growth-rate of coralline algae make them vulnerable to major disturbances, including anthropogenic disturbances and ocean acidification. Subtidal habitats dominated by crustose coralline algae are often associated with sea urchin-barren grounds and regarded as supporting limited invertebrate communities, especially compared with the adjacent kelp forests. Clathromorphum nereostratum is one of the most abundant crustose coralline algae found in the Aleutian Islands. Although the surface of this crustose alga exhibits little structural complexity, it can develop into crusts half-a-meter thick (2-10 cm in this study) that provide microhabitats for a variety of cryptic invertebrates. Despite the omnipresence of this alga throughout the nearshore Aleutians, very little is known about its associated faunal community. In the summers of 2006 and 2007, a benthic survey was conducted at 50 sites throughout the shallow (<20 m), nearshore Aleutian Islands as part of the Alaska Monitoring and Assessment Program. The habitat encountered at each site was categorized as soft sediment, macroalgae-dominated, or crustose corallinedominated. At each site, scuba divers sampled three 0.06-m 2 quadrats. Invertebrate communities associated with thick crustose coralline algae were compared with soft-sediment and macroalgae-dominated communities based on faunal abundance and diversity. Despite the depauperate appearance of crustose habitats, this study revealed that crustose environments support faunal communities as diverse and abundant as those found in rich macroalgal habitats. Keywords Crustose coralline algae. Kelp holdfast. Soft sediment. Urchin barren. Ocean acidification. Biodiversity This article belongs to the special issue "Marine Biodiversity under Change".

Formaldehyde runoff was an unintended impact of the anthrax decontamination procedure on the island of Gruinard. The death of intertidal organisms was observed where formaldehyde reached the shore during 1986. The extent to which shores on Gruinard have recovered was assessed with survey work in 2000. Recovery estimates were based on the hypothesis that the process of recolonization is partly dependent on species' dispersal capability. Underdevelopment of the assemblage of species lacking planktonic dispersal stages (direct developers) is therefore evidence that the process of recolonization is ongoing, rather than complete. A novel multivariate test showed that, when comparing quadrats from Gruinard and nearby mainland shores, assemblages of direct developing molluscs were significantly more distinct than assemblages of molluscs with planktonic dispersal stages. The average densities of species with direct development were generally lower on Gruinard than on mainland shores. While some species with direct development have similar densities on Gruinard and on the surrounding shores, the recovery of the overall assemblage was still incomplete after 14 years. In contrast, the harvested species, Littorina littorea, appeared to benefit from the absence of humans visiting Gruinard's shores. Populations of L. littorea on Gruinard contained significantly higher proportions of large individuals. Depending on the dispersal capabilities of different species, Gruinard is either still in recovery or acts as a reserve.

Mass extinctions documented by the fossil record provide critical benchmarks for assessing changes through time in biodiversity and ecology. Efforts to compare biotic crises of the past and present, however, encounter difficulty because taxonomic and ecological changes are decoupled, and although various metrics exist for describing taxonomic turnover, no methods have yet been proposed to quantify the ecological impacts of extinction events. To address this issue, we apply a network-based approach to exploring the evolution of marine animal communities over the Phanerozoic Eon. Network analysis of fossil co-occurrence data enables us to identify nonrandom associations of interrelated paleocommunities. These associations, or evolutionary paleocommunities, dominated total diversity during successive intervals of relative community stasis. Community turnover occurred largely during mass extinctions and radiations, when ecological reorganization resulted in the decline of one associatio...

We identiWed diVerent distributions of marine nonindigenous species (NIS) and native species on some artiWcial structures versus natural reefs and using experimental manipulations, revealed some possible causal mechanisms. In well-established subtidal assemblages, numbers of NIS were 1.5-2.5 times greater on pontoons or pilings than on rocky reefs, despite the local species pool of natives being up to 2.5 times greater than that of NIS. Conversely, on reefs and seawalls, numbers of native species were up to three times greater than numbers of NIS. DiVerential recruitment to diVerent positions and types of surfaces appeared to inXuence distribution patterns. NIS recruited well to most surfaces, particularly concrete surfaces near the surface of the water, whilst natives occurred infrequently on wooden surfaces. The position of rocky reefs and seawalls close to the shore and to the seabed appeared to make them favourable for the recruitment of natives, but this positioning alone does not hinder the recruitment of NIS. We argue that pontoons and pilings represent beachheads (i.e. entry points for invasion) for many nonindigenous epibiota and so enhance the spread and establishment of NIS in estuaries. Habitat creation in estuaries may, therefore, be a serious threat to native biodiversity.

Artificial hard substrates have been used to stabilize naturally soft bay shorelines for centuries. Despite the loss of over half of the natural shoreline in many bays, little attention has been paid to the communities inhabiting armored shorelines and to the ecological implications of armoring. The goal of the present study was to examine factors affecting spatial and temporal variation of intertidal, hard-substrate biota (emergent species and fishes), with emphases on the influence of exposure, distance from the open ocean, and similarity to open-coast, hard-substrate communities. We examined community composition at eight San Diego Bay (California, USA) sites (an exposed and a protected site at four bay locations) in June and November 2000 and two open-coast sites in August 2000. At all bay sites, the shore was armored with granite boulders, a form of shoreline stabilization referred to as ''riprap.'' Community structure was more variable spatially than temporally on the scales we studied, affected more by distance from the bay mouth and exposure to wave energy than by differences between June and November. Exposed sites near the bay mouth were more similar to natural open-coast sites, sharing about 45% of their species, than protected sites and sites farther from the mouth, which shared as few as 8%. Species richness was generally higher in exposed than protected bay sites. Species tended to occur higher in the intertidal zone at exposed than protected sites, and higher in November, when sea level was higher, than in June. Such results will be useful to shoreline managers who examine the ecological implications of hardening long stretches of coastline and may suggest ways to incorporate artificial structures into ecosystems in a more meaningful way.

The exchange of individuals among habitat patches (connectivity) has broad relevance for the conservation and management of marine metapopulations. Elemental fingerprinting-based research conducted over the past 12 years along the open coastline and bays of San Diego County in southern California evaluated connectivity patterns for seven species: one native and two invasive mussels, an oyster, a brachyuran crab, and two fishes. The studies spanned different years and seasons but overlapped considerably in space, allowing comparisons of dispersal patterns across species, and assessment of the relative importance of location, circulation, and intra-annual and inter-annual variability. We asked whether the species exhibited commonalities in directional transport, transport distances, sources and sinks, self-recruitment, and bay-ocean exchange. Linked connectivity-demographic analyses conducted for two species of mytilid mussels and two fishes allowed evaluation of the contributions of realized connectivity to metapopulation dynamics relative to other life-history attributes. Common trends across species include average along-shore dispersal distances of 15-35 km and seasonal changes in direction of dispersal that mirrored patterns of along-shore circulation. We observed greater isolation of back-bay populations, significant exchange from front bay to ocean, and high self-recruitment in locations on the northern, open coast, and in the southern bays. Connectivity was rarely the most influential driver of growth and persistence of metapopulations, but influenced the importance of other vital rates. Several locations served consistently as sources of larvae or as nurseries for multiple species, but there were few sites in common that were sinks. For the mussels, reproductive timing guided directional transport. These results imply that local management (e.g., habitat protection, opening of the mouths of lagoons, location of aquaculture farms) may be effective along this coastline. Regional, multi-species assessments of exchange of larvae should move us closer to ecosystem-based management.

Coral decline in the Caribbean is marked by the loss of habitat-forming corals, such as elkhorn coral (Acropora palmata). Elkhorn coral recovery has been isolated and patchy, but recently a "re-sheeting" phenomenon, in which elkhorn tissue grows over standing dead coral skeletons, was observed along the reefs in the Mexican Yucatán peninsula. Little is known about the ecological factors contributing to "re-sheeting," but it is hypothesized that grazing from herbivores provides top-down control of algal growth and promotes coral recovery. The purpose of this study was to evaluate the status of elkhorn populations in Akumal, Mexico and determine if Diadema urchins or parrotfish populations are associated with higher elkhorn abundance and lower algal cover. To achieve this objective, we surveyed 12 spur and groove reef sites in Akumal, where re-sheeting was recently observed, and measured elkhorn coral and herbivore population metrics. We found that both herbivore groups are associated with increasing elkhorn coral presence and cover, and lower macroalgal cover. Additionally, we tested for sampling bias in counting Diadema urchins and found that a significant difference in urchins counts between paired day and night transects on shallow, high complexity reefs. Our results suggest that historically important herbivore groups may be contributing to the recovery of elkhorn coral in Akumal by facilitating tissue re-sheeting.

Mass extinctions documented by the fossil record provide critical benchmarks for assessing changes through time in biodiversity and ecology. Efforts to compare biotic crises of the past and present, however, encounter difficulty because taxonomic and ecological changes are decoupled, and although various metrics exist for describing taxonomic turnover, no methods have yet been proposed to quantify the ecological impacts of extinction events. To address this issue, we apply a network-based approach to exploring the evolution of marine animal communities over the Phanerozoic Eon. Network analysis of fossil co-occurrence data enables us to identify nonrandom associations of interrelated paleocommunities. These associations, or evolutionary paleocommunities, dominated total diversity during successive intervals of relative community stasis. Community turnover occurred largely during mass extinctions and radiations, when ecological reorganization resulted in the decline of one association and the rise of another. Altogether, we identify five evolutionary paleocommunities at the generic and familial levels in addition to three ordinal associations that correspond to Sepkoski’s Cambrian, Paleozoic, and Modern evolutionary faunas. In this context, we quantify magnitudes of ecological change by measuring shifts in the representation of evolutionary paleocommunities over geologic time. Our work shows that the Great Ordovician Biodiversification Event had the largest effect on ecology, followed in descending order by the Permian–Triassic, Cretaceous–Paleogene, Devonian, and Triassic–Jurassic mass extinctions. Despite its taxonomic severity, the Ordovician extinction did not strongly affect co-occurrences of taxa, affirming its limited ecological impact. Network paleoecology offers promising approaches to exploring ecological consequences of extinctions and radiations.