Biogenic Habitats Research Articles

Global patterns of kelp forest change over the past half-century

Kelp forests (Order Laminariales) form key biogenic habitats in coastal regions of temperate and Arctic seas worldwide, providing ecosystem services valued in the range of billions of dollars annually. Although local evidence suggests that kelp forests are increasingly threatened by a variety of stressors, no comprehensive global analysis of change in kelp abundances currently exists. Here, we build and analyze a global database of kelp time series spanning the past half-century to assess regional and global trends in kelp abundances. We detected a high degree of geographic variation in trends, with regional variability in the direction and magnitude of change far exceeding a small global average decline (instantaneous rate of change = -0.018 y-1). Our analysis identified declines in 38% of ecoregions for which there are data (-0.015 to -0.18 y-1), increases in 27% of ecoregions (0.015 to 0.11 y-1), and no detectable change in 35% of ecoregions. These spatially variable trajectories reflected regional differences in the drivers of change, uncertainty in some regions owing to poor spatial and temporal data coverage, and the dynamic nature of kelp populations. We conclude that although global drivers could be affecting kelp forests at multiple scales, local stressors and regional variation in the effects of these drivers dominate kelp dynamics, in contrast to many other marine and terrestrial foundation species.

Understory algae associations and predation risk influence broad-scale kelp habitat use in a temperate reef fish

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 559:147-158 (2016) - DOI: https://doi.org/10.3354/meps11892 Understory algae associations and predation risk influence broad-scale kelp habitat use in a temperate reef fish Alejandro Pérez-Matus1,*, Fernando Sánchez1, Juan C. González-But1, Robert W. Lamb2 1Subtidal Ecology Laboratory and Center for Marine Conservation, Estación Costera de Investigaciones Marinas, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile 2Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912, USA *Corresponding author: aperez@bio.puc.cl ABSTRACT: Habitat selection and predation are ecological processes that operate at small spatial scales. How these influence large-scale patterns in abundance and distribution of fauna remains to be resolved, especially in structurally complex systems such as kelp beds. In order to explain whether habitat selection, differential predation, or a combination of factors explain variation in fish abundance among sites, we conducted field surveys of abundance and microhabitat use of a temperate reef fish (Tripterygiidae, Helcogrammoides cunninghami Smitt, 1898) at sites of varying kelp cover and different understory algal assemblages. We observed variation in abundance among sites and, particularly, that sites with abundant kelp individuals have 4 times fewer fish. In order to explain these differences in habitat use and variation in abundance among sites, we conducted choice chamber experiments in the laboratory and tethering experiments in the field. In the laboratory, individuals tend to discriminate among options by selecting substrata with understory biogenic habitat (i.e. filamentous algae) and avoiding kelp. Finally, tethering experiments in the field evaluating H. cunninghami mortality rates in preferred habitat types compared to kelp beds confirmed an increase in predator richness and a 2-fold increase in predation rates inside kelp habitats. Together, these results suggest that multiple mechanisms that operate mainly at small spatial scales (predation and habitat selection) may influence the distribution and abundance of organisms over large areas. KEY WORDS: Reef fish · Kelp forest · Habitat selection · Mortality rates Full text in pdf format Supplementary material PreviousNextCite this article as: Pérez-Matus A, Sánchez F, González-But JC, Lamb RW (2016) Understory algae associations and predation risk influence broad-scale kelp habitat use in a temperate reef fish. Mar Ecol Prog Ser 559:147-158. https://doi.org/10.3354/meps11892 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 559. Online publication date: November 09, 2016 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2016 Inter-Research.

Seasonal variation in epifaunal communities associated with giant kelp (Macrocystis pyrifera) at an upwelling‐dominated site

AbstractKelp forests are highly productive and species‐rich benthic ecosystems in temperate regions that provide biogenic habitat for numerous associated species. Diverse epifaunal communities inhabit kelp sporophytes and are subject to variations in the physical environment and to changes experienced by the kelp habitat itself. We assessed seasonal variations in epifaunal invertebrate communities inhabiting giant kelps, Macrocystis pyrifera, and their effects on this seaweed. Six seasonal samplings were conducted over a year at an upwelling‐dominated site in northern‐central Chile where physical conditions are known to fluctuate temporally. More than 30 taxa were identified, among which peracarid crustaceans stood out in both diversity and abundance. Species richness and abundance differed among sporophyte sections (holdfast and fronds) and throughout the year. The frond community was dominated by two grazers (the amphipod Peramphithoe femorata and the isopod Amphoroidea typa), while suspension feeders, grazers, and omnivores (the amphipod Aora typica, the isopod Limnoria quadripunctata, and polychaetes) dominated the holdfasts. Abundances of the dominant species fluctuated throughout the year but patterns of variation differed among species. The most abundant grazer (P. femorata) had highest densities in summer, while the less abundant grazer (A. typa) reached its peak densities in winter. Interestingly, the area of kelp damaged by grazers was highest in autumn and early winter, suggesting that grazing impacts accumulate during periods of low kelp growth, which can thus be considered as ‘vestiges of herbivory past.’ Among the factors determining the observed seasonal patterns, strong variability of environmental conditions, reproductive cycles of associated fauna, and predation by fishes vary in importance. Our results suggest that during spring and early summer, bottom‐up processes shape the community structure of organisms inhabiting large perennial seaweeds, whereas during late summer and autumn, top‐down processes are more important.

The ecological legacy of 20th century acidification carried on by ecosystem engineers

AbstractAimsAcidification by airborne pollution strongly degraded terrestrial and aquatic ecosystems until the late 20th century. Although geochemical recovery has been observed since then, there has been little recovery of ecological communities, and the reasons are unclear. Positive feedbacks between anthropogenic acidification and ecosystem engineers are likely to contribute to this lag in recovery, but are under‐investigated so far. Here we hypothesize that positive feedbacks between past anthropogenic acidification and on‐going biogenic habitat modification by peat moss species (genus Sphagnum) will have long‐term effects on plant community composition of acidified spring fens.LocationSpring fens in forest landscapes of central Germany's siliceous mountain ranges impacted by anthropogenic acidification until the late 1980s, and with strong increases in abundance of Sphagnum during the last 25 yrs.MethodsVegetation surveys (vascular plants, mosses and liverworts) and hydro‐chemical water measurements of 54 spring fens over a study period of 25 yrs (1989–2013). Measurements of water pH and discharge were used, in combination with Ellenberg indicator values of the occurring plant species, to investigate the joint effects of anthropogenic acidification and biogenic habitat modification.ResultsChanging plant communities (excluding Sphagnum spp.) indicated significant increases in acidification of spring fens with high Sphagnum cover, although pH of the outpouring groundwater showed no temporal trends. Path analysis revealed significant enhancing effects of Sphagnum abundance on the community‐indicated acidity, which was independent of the abiotic acidity regime (water pH). With increasing species richness through time, community assembly became increasingly similar and shifted towards acid‐tolerant species. Characteristic plant species of non‐acidified spring fens like Chrysosplenium oppositifolium were replaced by generalist grass, sedge and tree species (e.g., Picea abies, Fagus sylvatica, Calamagrostis villosa and Carex remota).ConclusionsBased on long‐term monitoring data we show that biogenic habitat modification by ecosystem engineers can significantly change plant community composition on a decadal scale in a landscape where historic anthropogenic acidification heavily impacted ecosystem functioning. These complex functional legacies stress the importance of considering the history and memory of ecosystems in global change impact research.

Grazer diversity interacts with biogenic habitat heterogeneity to accelerate intertidal algal succession.

Environmental heterogeneity contributes to coexistence by allowing species with different traits to persist when different species perform best at different times or places. This interaction between niche differences and environmental variability may also help explain relationships between biodiversity and ecosystem functioning, but few data are available to rigorously evaluate this hypothesis. We assessed how a biologically relevant aspect of environmental heterogeneity interacts with species diversity to determine ecosystem processes in a natural rocky intertidal community. We used field removals to factorially manipulate biogenic habitat heterogeneity (barnacles, bare rock, and plots that were 50/50 mixes of the two habitat types) and gastropod grazer species richness and then tracked algal community succession and recovery over the course of 1yr. We found that herbivore diversity, substrate heterogeneity, and their interaction played unique roles in the peak abundance and timing of occurrence of different algal functional groups. Early successional microalgae were most heavily grazed in diverse herbivore assemblages and those with barnacles present, which was likely due to complementary feeding strategies among all three grazers. In contrast, late successional macroalgae were strongly influenced by the presence of a habitat generalist limpet. In this herbivore's absence, heterogeneous habitats (i.e., mixtures of bare rock and barnacles) experienced the greatest algal accumulation, which was partly a result of complementary habitat use by the remaining herbivores. The complex way habitat identity and heterogeneity altered grazer-algal interactions in our study suggests species' differences and environmental heterogeneity both separately and interactively contribute to the relationship between biodiversity and ecosystem functions.

Novel Indicators of Anthropogenic Influence on Marine and Coastal Ecosystems

Human populations are concentrated along coastal regions worldwide, placing a disproportionate stress on coastal marine ecosystems. Ironically, biogenic habitats may be adversely affected by human activities though they serve to attenuate the impacts of global change on coastal cities. Surprisingly, simple, coastwide indicators of anthropogenic influences in relation to the spatial distribution of biogenic habitats are relatively underdeveloped. In this paper, we introduce a spatially explicit index of coastal as well as upland riverine human population proximity, based on human population and river dynamics datasets on the West- and Gulf-Coasts of the US. We then examine the relationship between these indices and biogenic habitats (kelp and mangrove forests). Finally, we identify patterns of landscape-scale biodiversity with human populations, and explore occurrence of biogenic habitats within and outside of marine protected areas (MPAs). We found that biogenic habitats were negatively associated with human populations and that MPAs were generally placed away from people. Landscape-scale patterns of biodiversity did not differ within and outside kelp forests and MPAs on the West Coast, but had a negative association with mangroves and a positive association with MPAs on the Gulf Coast. This index can be used anywhere in the world, can project into the future using various human population growth forecasts, and can serve as an important method for conservation triage.

Drilling predation increased in response to changing environments in the Caribbean Neogene

AbstractChanges in the physical environment are major drivers of evolutionary change, either through direct effects on the distribution and abundance of species or more subtle shifts in the outcome of biological interactions. To investigate this phenomenon, we built a fossil data set of drilling gastropod predation on bivalve prey for the last 11 Myr to determine how the regional collapse in Caribbean upwelling and planktonic productivity affected predator–prey interactions. Contrary to theoretical expectations, predation increased nearly twofold after productivity declined, while the ratio of drilling predators to prey remained unchanged. This increase reflects a gradual, several-fold increase in the extent of shallow-water coral reefs and seagrass meadows in response to the drop in productivity that extended over several million years. Drilling predation is uniformly higher in biogenic habitats than in soft sediments. Thus, changes in predation intensity were driven by a shift in dominant habitats rather than a direct effect of decreased productivity. Most previous analyses of predation through time have not accounted for variations in environmental conditions, raising questions about the patterns observed. More fundamentally, however, the consequences of large-scale environmental perturbations may not be instantaneous, especially when changes in habitat and other aspects of local environmental conditions cause cascading series of effects.

Microspatial variability in community structure and photophysiology of calcified macroalgal microbiomes revealed by coupling of hyperspectral and high-resolution fluorescence imaging.

Calcifying coralline macroalgae provide biogenic habitats colonised by epiphytic microalgae that contribute significantly to community productivity. Georeferenced hyperspectral and high-resolution fluorescence imaging were coupled to microspatially mapped community composition and relative biomass of macroalgal host and epiphyte microalgal groups, and their weighted contributions to productivity within host fronds of Corallina officinalis on upper and lower zones of a rocky shore were determined. Lower shore epiphytes were dominated by filamentous diatoms (Bacillariophyta), confined to the apex of the frond structure, which were low light acclimated but retained a high capacity for photoprotective down regulation and contributed up to 51% of total community productivity. Upper shore epiphytes were dominated by green algae (Chlorophyta) and single-celled diatoms (principally Cocconeis spp.), which were high light acclimated but present at far lower relative biomass and contributed negligibly to productivity. The host, C. officinalis was the main primary producer. Variation in light environment resulting from differences in shore height and shading within the host macroalga, likely play a large role in determining patterns in epiphyte community structure, biomass and productivity observed. Additionally, microspatial gradients in photophysiological parameters along the host macroalga likely resulted from age-dependent variation in pigments as well as the gradient in light environment.

Does ecological redundancy maintain functioning of marine benthos on centennial to millennial time scales?

AbstractPredicting the ability of the biosphere to continue to deliver ecosystem services in the face of biodiversity loss and environmental change is a major challenge. The results of short‐term and small‐scale experimental studies are both equivocal and difficult to extrapolate from. In this study we use data on benthic palaeocommunities covering 4,000,000 years (in the Late Jurassic when temperate coastal seas in NW Europe experienced fluctuations in oxygenation). The biological traits associated with each species in the palaeocommunities were combined to index the delivery of ecological functions. Five ecosystem functions were examined: food for large mobile predators, biogenic habitat provision, nutrient recycling/regeneration, inorganic carbon sequestration and food‐web dynamics. In modern systems these ecological functions underpin ecosystem services that are important for human well‐being. Our results show that the supply of food for higher predators was remarkably constant during the 4,000,000 years, suggesting that redundancy amongst species in the assemblage drives the biodiversity–ecosystem function (BEF) relationship. By contrast, the provision of biogenic habitat varied with the occurrence of a relatively few taxa, a pattern consistent with a rivet type model of BEF. For nutrient regeneration, carbon sequestration and food‐web dynamics the patterns were complex and suggestive of an idiosyncratic model of BEF. To our knowledge this is the first study to quantify ecological functioning through deep time and demonstrates the utility of this approach to understanding long‐term patterns of BEF in both ancient and contemporary marine ecosystems. The delivery of all five ecological functions studied became increasingly variable as the regional climate became drier, thus modifying the supply of terrigenous nutrient inputs.

The use of multibeam backscatter and bathymetry as a means of identifying faunal assemblages in a deep-sea cold seep

Deep-sea ecosystems have attracted considerable commercial interest in recent years because of their potential to sustain a diverse range of mankind's industrial needs. If these systems are to be preserved or exploited in a sustainable manner, mapping habitats and species distributions is critical. As biodiversity at cold-seeps or other deep-sea ecosystems is driven by habitat heterogeneity, imagery is the obvious choice for characterizing these systems and has indeed proven extremely valuable towards mapping biogenic habitats formed by dense aggregations of large sized species, such as coral reefs, tubeworm bushes or bivalve beds. However, the acquisition of detailed images with resolution sufficient for reliable identification is extremely time consuming, labor intensive and highly susceptible to logistical issues. We developed a novel method for quickly mapping cold seep fauna and habitats over large areas, at the scale of squares of kilometers. Our method uses multibeam echosounder bathymetry and acoustic backscatter data, both segmented and reclassified based on topographical features and then combined to obtain a raster containing unique values incorporating both backscatter and bathymetry data. Two datasets, obtained from 30m and 8m above the seafloor were used and the results from the two datasets were compared. The method was applied to a cold seep community located in a pockmark in the deep Congo channel and we were able to ground truth the accuracy of our method against images of the area. The two datasets, obtained from different altitudes gave varying results: the 8m altitude dataset reliably predicted tubeworms and carbonate rock, while the 30m altitude dataset predicted tubeworms and vesicomyid clams. The 30m dataset was more accurate than the 8m altitude dataset in predicting distributions of tubeworms. Overall, all the predictions were quite accurate, with at least 90% of predictions being within 5m of real distributions.

Coralline red algae (Corallinales sensu lato) in the Atlantic Iberian Peninsula: current state of knowledge.

Event Abstract Back to Event Coralline red algae (Corallinales sensu lato) in the Atlantic Iberian Peninsula: current state of knowledge. Juan Lugilde1*, Viviana Peña1 and Ignacio Bárbara1 1 University of La Coruña, Animal Biology, Vegetal Biology & Ecology, Spain Coralline red algae (Corallinales sensu lato) are characterized by having cells walls composed of calcium carbonate. They have a worldwide distribution, and occur from the intertidal to 250 m depth. Moreover, their ecological role as ecosystem engineers promote and increase local diversity such as the biogenic habitats known as maerl beds and the Mediterranean coralligenous. This group exhibits a great morphological diversity although it was traditionally grouped under two broad morphologies: (a) articulated, with fronds alternating calcified and decalcified segments and (b) non-articulated, with thallus entirely calcified. From the systematic point of view, Corallinales sensu lato currently encompasses three orders (Corallinales, Hapalidiales and Sporolithales) containing 35 genera and 600 species recorded worldwide. However, at regional scale, the diversity of coralline red algae is little known mainly because the difficulty in overcoming the morphological plasticity of external features. In order to assess the current state of knowledge of Corallinales in the Atlantic Iberian Peninsula, and compare it with adjacent Atlantic and Mediterranean areas, we reviewed information compiled from more than 250 publications, grey data and herbarium collections. Our results pointed out that the Atlantic Iberian coralline algae was scarcely studied, and it showed the lowest diversity. From 129 coralline taxa recorded, Macaronesia is the most species-rich region (71% of the total), followed by the Iberian Mediterranean (52%), the British Isles-Atlantic France (48)%, and the Atlantic Iberian Peninsula (37%). In our region, 17 species occurred commonly (> 50% of the coastline), particularly those corresponding to the genera Lithophyllum, Jania, Amphiroa, Mesophyllum and Phymatolithon. By contrast, other genera occasionally reported (Hydrolithon, Leptophytum, Lithothamnion and Pneophyllum) were probably overlooked and susceptible to appear by their presence in remaining adjacent regions. Regarding growth-form and habitat preferences of coralline red algae, our review indicated that the epilithic habit was dominant, followed by the epiphytic, epizoic and the unattached (maerl/rodoliths). Besides, sciaphilous taxa were more abundant than photophilous species. Lower intertidal and shallow subtidal habitats as well as semi-exposed shores or with current action harbor a high diversity of coralline algae, while rocky subtidal coasts are poor in species and probably overlooked. The present study confirms that the Atlantic Iberian coralline algae are scarcely studied, and further research is required, especially in those genera and habitats barely known. To overcome this gap of knowledge, we are conducting an extensive study of this group in Galicia (NW Iberian Peninsula). Apart from improving the knowledge about this group in terms of diversity and systematics updating, we aimed to develop an illustrated and descriptive flora with species descriptions, habitat, distribution information, and keys to facilitate their identification by the Atlantic Iberian scientific community. Keywords: Coralline algae, diversity, habitat, review, Atlantic Iberian, Galicia. Conference: XIX Iberian Symposium on Marine Biology Studies, Porto, Portugal, 5 Sep - 9 Sep, 2016. Presentation Type: Poster Presentation Topic: 1. ECOLOGY, BIODIVERSITY AND VULNERABLE ECOSYSTEMS Citation: Lugilde J, Peña V and Bárbara I (2016). Coralline red algae (Corallinales sensu lato) in the Atlantic Iberian Peninsula: current state of knowledge.. Front. Mar. Sci. Conference Abstract: XIX Iberian Symposium on Marine Biology Studies. doi: 10.3389/conf.FMARS.2016.05.00136 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 26 Apr 2016; Published Online: 03 Sep 2016. * Correspondence: PhD. Juan Lugilde, University of La Coruña, Animal Biology, Vegetal Biology & Ecology, La Coruña, La Coruña, 15001, Spain, juan.lugilde@udc.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Juan Lugilde Viviana Peña Ignacio Bárbara Google Juan Lugilde Viviana Peña Ignacio Bárbara Google Scholar Juan Lugilde Viviana Peña Ignacio Bárbara PubMed Juan Lugilde Viviana Peña Ignacio Bárbara Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Regional- and local-scale variations in benthic megafaunal composition at the Arctic deep-sea observatory HAUSGARTEN

The Long-Term Ecological Research (LTER) observatory HAUSGARTEN, in the eastern Fram Strait, provides us the valuable ability to study the composition of benthic megafaunal communities through the analysis of seafloor photographs. This, in combination with extensive sampling campaigns, which have yielded a unique data set on faunal, bacterial, biogeochemical and geological properties, as well as on hydrography and sedimentation patterns, allows us to address the question of why variations in megafaunal community structure and species distribution exist within regional (60–110km) and local (<4km) scales.Here, we present first results from the latitudinal HAUSGARTEN gradient, consisting of three different stations (N3, HG-IV, S3) between 78°30′N and 79°45′N (2351–2788m depth), obtained via the analysis of images acquired by a towed camera (OFOS-Ocean Floor Observation System) in 2011. We assess variability in megafaunal densities, species composition and diversity as well as biotic and biogenic habitat features, which may cause the patterns observed. While there were significant regional-scale differences in megafaunal composition and densities between the stations (N3=26.74±0.63; HG-IV=11.21±0.25; S3=18.34±0.39 individuals m−2), significant local differences were only found at HG-IV.Regional-scale variations may be due to the significant differences in ice coverage at each station as well as the different quantities of protein available, whereas local-scale differences at HG-IV may be a result of variation in bottom topography or factors not yet identified.

The structure of biogenic habitat and epibiotic assemblages associated with the global invasive kelp Undaria pinnatifida in comparison to native macroalgae

Kelp forests dominate temperate and polar rocky coastlines and represent critical marine habitats because they support elevated rates of primary and secondary production and high biodiversity. A major threat to the stability of these ecosystems is the proliferation of non-native species, such as the Japanese kelp Undariapinnatifida (‘Wakame’), which has recently colonised natural habitats in the UK. We quantified the abundance and biomass of U. pinnatifida on a natural rocky reef habitat over 10 months to make comparisons with three native canopy-forming brown algae (Laminaria ochroleuca, Saccharina latissima, and Saccorhiza polyschides). We also examined the biogenic habitat structure provided by, and epibiotic assemblages associated with, U. pinnatifida in comparison to native macroalgae. Surveys conducted within the Plymouth Sound Special Area of Conservation indicated that U. pinnatifida is now a dominant and conspicuous member of kelp-dominated communities on natural substrata. Crucially, U. pinnatifida supported a structurally dissimilar and less diverse epibiotic assemblage than the native perennial kelp species. However, U. pinnatifida-associated assemblages were similar to those associated with Saccorhiza polyschides, which has a similar life history and growth strategy. Our results suggest that a shift towards U. pinnatifida dominated reefs could result in impoverished epibiotic assemblages and lower local biodiversity, although this could be offset, to some extent, by the climate-driven proliferation of L. ochroleuca at the poleward range edge, which provides complex biogenic habitat and harbours relatively high biodiversity. Clearly, greater understanding of the long-term dynamics and competitive interactions between these habitat-forming species is needed to accurately predict future biodiversity patterns.

Application of species distribution models to explain and predict the distribution, abundance and assemblage structure of nearshore temperate reef fishes

AbstractAimThe purpose of this study was to create predictive species distribution models (SDMs) for temperate reef‐associated fish species densities and fish assemblage diversity and richness to aid in marine conservation and spatial planning.LocationCalifornia, USA.MethodsUsing generalized additive models, we associated fish species densities and assemblage characteristics with seafloor structure, giant kelp biomass and wave climate and used these associations to predict the distribution and assemblage structure across the study area. We tested the accuracy of these predicted extrapolations using an independent data set. The SDMs were also used to estimate larger scale abundances to compare with other estimates of species abundance (uniform density extrapolation over rocky reef and density extrapolations taking into account variations in geomorphic structure).ResultsThe SDMs successfully modelled the species–habitat relationships of seven rocky reef‐associated fish species and showed that species’ densities differed in their relationships with environmental variables. The predictive accuracy of the SDMs ranged from 0.26 to 0.60 (Pearson's r correlation between observed and predicted density values). The SDMs created for the fish assemblage‐level variables had higher prediction accuracies with Pearson's r values of 0.61 for diversity and 0.71 for richness. The comparisons of the different methods for extrapolating species densities over a single marine protected area varied greatly in their abundance estimates with the uniform extrapolation (density values extrapolated evenly over the rocky reef) always estimating much greater abundances. The other two methods, which took into account variation in the geomorphic structure of the reef, provided much lower abundance estimates.Main conclusionsSpecies distribution models that combine geomorphic, oceanographic and biogenic habitat variables can reliably predict spatial patterns of species density and assemblage attributes of temperate reef fishes at spatial scales of 50 m. Thus, SDMs show great promise for informing spatial and ecosystem‐based approaches to conservation and fisheries management.

Impacts from Partial Removal of Decommissioned Oil and Gas Platforms on Fish Biomass and Production on the Remaining Platform Structure and Surrounding Shell Mounds.

When oil and gas platforms become obsolete they go through a decommissioning process. This may include partial removal (from the surface to 26 m depth) or complete removal of the platform structure. While complete removal would likely eliminate most of the existing fish biomass and associated secondary production, we find that the potential impacts of partial removal would likely be limited on all but one platform off the coast of California. On average 80% of fish biomass and 86% of secondary fish production would be retained after partial removal, with above 90% retention expected for both metrics on many platforms. Partial removal would likely result in the loss of fish biomass and production for species typically found residing in the shallow portions of the platform structure. However, these fishes generally represent a small proportion of the fishes associated with these platforms. More characteristic of platform fauna are the primarily deeper-dwelling rockfishes (genus Sebastes). “Shell mounds” are biogenic reefs that surround some of these platforms resulting from an accumulation of mollusk shells that have fallen from the shallow areas of the platforms mostly above the depth of partial removal. We found that shell mounds are moderately productive fish habitats, similar to or greater than natural rocky reefs in the region at comparable depths. The complexity and areal extent of these biogenic habitats, and the associated fish biomass and production, will likely be reduced after either partial or complete platform removal. Habitat augmentation by placing the partially removed platform superstructure or some other additional habitat enrichment material (e.g., rock boulders) on the seafloor adjacent to the base of partially removed platforms provides additional options to enhance fish production, potentially mitigating reductions in shell mound habitat.

The impacts of deep-sea fisheries on benthic communities: a review

AbstractDeep-sea fisheries operate globally throughout the world's oceans, chiefly targeting stocks on the upper and mid-continental slope and offshore seamounts. Major commercial fisheries occur, or have occurred, for species such as orange roughy, oreos, cardinalfish, grenadiers and alfonsino. Few deep fisheries have, however, been sustainable, with most deep-sea stocks having undergone rapid and substantial declines. Fishing in the deep sea not only harvests target species but can also cause unintended environmental harm, mostly from operating heavy bottom trawls and, to a lesser extent, bottom longlines. Bottom trawling over hard seabed (common on seamounts) routinely removes most of the benthic fauna, resulting in declines in faunal biodiversity, cover and abundance. Functionally, these impacts translate into loss of biogenic habitat from potentially large areas. Recent studies on longline fisheries show that their impact is much less than from trawl gear, but can still be significant. Benthic taxa, especially the dominant mega-faunal components of deep-sea systems such as corals and sponges, can be highly vulnerable to fishing impacts. Some taxa have natural resilience due to their size, shape, and structure, and some can survive in natural refuges inaccessible to trawls. However, many deep-sea invertebrates are exceptionally long-lived and grow extremely slowly: these biological attributes mean that the recovery capacity of the benthos is highly limited and prolonged, predicted to take decades to centuries after fishing has ceased. The low tolerance and protracted recovery of many deep-sea benthic communities has implications for managing environmental performance of deep-sea fisheries, including that (i) expectations for recovery and restoration of impacted areas may be unrealistic in acceptable time frames, (ii) the high vulnerability of deep-sea fauna makes spatial management—that includes strong and consistent conservation closures—an important priority, and (iii) biodiversity conservation should be &amp;gt; balanced with options for open areas that support sustainable fisheries.

A computerized database (CorMol) on the molluscan fauna from the Mediterranean reef ecosystems: Part I, the coralligenous formations

In the Mediterranean Sea, infralittoral and circalittoral rocky bottoms (from 15 to 120 m) are characterized by a biogenic habitat, named “coralligenous”, formed by the concretion of calcareous organisms, mainly algal thalli, and to a lesser extent by animal skeletons. This complex habitat is inhabited by a rich fauna that belongs to different taxonomic groups. Sponges, bryozoans, cnidarians and ascidians are the most common sessile organisms that inhabit the area, while crustacea and molluscs are the most common mobile organisms. Little information on the diversity of the molluscs that thrive in the coralligenous habitat is known, though this information is highly important for biodiversity management purposes. A database for the molluscs of the coralligenous habitat was compiled and a method implemented for the management of this information. More than 511 species of molluscs have been recorded so far from the coralligenous formations, the majority of which belong to the class Gastropoda (357 sp.) followed by Bivalvia (137 sp.), Polyplacophora (14 sp.), Cephalopoda (2 sp.) and Scaphopoda (1 sp.). Among these, the gastropod Luria lurida (Linnaeus, 1758) and Charonia lampas (Linnaeus, 1758), the endemic bivalve Pinna nobilis (Linnaeus, 1758) and the endolithic bivalve Lithophaga lithophaga (Linnaeus, 1758), are protected by international conventions.

Biodiversity on the Rocks: Macrofauna Inhabiting Authigenic Carbonate at Costa Rica Methane Seeps.

Carbonate communities: The activity of anaerobic methane oxidizing microbes facilitates precipitation of vast quantities of authigenic carbonate at methane seeps. Here we demonstrate the significant role of carbonate rocks in promoting diversity by providing unique habitat and food resources for macrofaunal assemblages at seeps on the Costa Rica margin (400–1850 m). The attendant fauna is surprisingly similar to that in rocky intertidal shores, with numerous grazing gastropods (limpets and snails) as dominant taxa. However, the community feeds upon seep-associated microbes. Macrofaunal density, composition, and diversity on carbonates vary as a function of seepage activity, biogenic habitat and location. The macrofaunal community of carbonates at non-seeping (inactive) sites is strongly related to the hydrography (depth, temperature, O2) of overlying water, whereas the fauna at sites of active seepage is not. Densities are highest on active rocks from tubeworm bushes and mussel beds, particularly at the Mound 12 location (1000 m). Species diversity is higher on rocks exposed to active seepage, with multiple species of gastropods and polychaetes dominant, while crustaceans, cnidarians, and ophiuroids were better represented on rocks at inactive sites. Macro-infauna (larger than 0.3 mm) from tube cores taken in nearby seep sediments at comparable depths exhibited densities similar to those on carbonate rocks, but had lower diversity and different taxonomic composition. Seep sediments had higher densities of ampharetid, dorvilleid, hesionid, cirratulid and lacydoniid polychaetes, whereas carbonates had more gastropods, as well as syllid, chrysopetalid and polynoid polychaetes. Stable isotope signatures and metrics: The stable isotope signatures of carbonates were heterogeneous, as were the food sources and nutrition used by the animals. Carbonate δ13Cinorg values (mean = -26.98‰) ranged from -53.3‰ to +10.0‰, and were significantly heavier than carbonate δ13Corg (mean = -33.83‰), which ranged from -74.4‰ to -20.6‰. Invertebrates on carbonates had average δ13C (per rock) = -31.0‰ (range -18.5‰ to -46.5‰) and δ15N = 5.7‰ (range -4.5‰ to +13.4‰). Average δ13C values did not differ between active and inactive sites; carbonate fauna from both settings depend on chemosynthesis-based nutrition. Community metrics reflecting trophic diversity (SEAc, total Hull Area, ranges of δ13C and δ15N) and species packing (mean distance to centroid, nearest neighbor distance) also did not vary as a function of seepage activity or site. However, distinct isotopic signatures were observed among related, co-occurring species of gastropods and polychaetes, reflecting intense microbial resource partitioning. Overall, the substrate and nutritional heterogeneity introduced by authigenic seep carbonates act to promote diverse, uniquely adapted assemblages, even after seepage ceases. The macrofauna in these ecosystems remain largely overlooked in most surveys, but are major contributors to biodiversity of chemosynthetic ecosystems and the deep sea in general.

The Enlargement of the Suez Canal and Introduction of Non‐Indigenous Species to the Mediterranean Sea

The Suez Canal is one of the most important waterways in the world – during the last year 17,148 ships passed through the Canal – reducing emissions, saving time, and operating costs to shippers. The rapid increase in ship size from the “Post-Suezmax” (> 12,000 TEU) to the latest container vessels (> 19,000 TEU) now requires enlargements of port facilities and canals. A project of this magnitude, and with potentially negative environmental outcomes, requires a transparent and scientifically sound “Environmental Impact Assessment” (EIA). An explicit obligation on Parties to the Convention on Biological Diversity (https://www.cbd.int/doc/ legal/cbd-en.pdf) was made to consider transboundary impacts on biodiversity, particularly those associated with invasive non-indigenous species. Although a nonbinding instrument, the “Rio Declaration on Environment and Development” sets forth important principles of international environmental law (UN 1992): States are responsible for ensuring that activities within their jurisdiction do not damage the environment of other States, and EIA, as a national instrument, shall be undertaken for proposed activities that are likely to have a significant adverse impact on the environment. To our knowledge, no Environmental Impact Assessment has been

New opportunities for conservation of a threatened biogenic habitat: a worldwide assessment of knowledge on bivalve-reef representation in marine and coastal Ramsar Sites

The present study draws attention to the current state of knowledge of bivalve reef, an important but historically overlooked habitat type. Recent interest has led to the explicit recognition of this habitat type under the Convention on Wetlands of International Importance (the Ramsar Convention), an international treaty that has widespread governmental and scientific involvement. To assess the state of knowledge, the Information Sheet on Ramsar Wetlands (RIS) for marine and coastal Sites was searched for evidence that bivalve-reef habitat is present in the site. We then examined the quality of this information using alternative data sources. These were public databases of geolocated species records at three spatial scales, local and regional experts, and a general web search. It was found that of the 893 marine and coastal Ramsar Sites considered, the RIS for 16 Sites provided strong evidence of bivalve-reef habitat and 99 had confirmed presence of reef-forming bivalves, a strikingly high number, given that it is not yet compulsory to include bivalve reef in RISs. However, the alternative information sources identified bivalve reefs or reef-forming bivalves in 142 further Sites. No one information source provided comprehensive information, highlighting the overall poor state of knowledge of this habitat type.