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Abstract The rocky shores in Chile have a wide invertebrate species diversity, that include species with marked abundances in determined regions. The aim of the present study is to analyse the spatial distribution pattern in different marine invertebrate species in rocky shore of Araucania region, considering if these species have random, uniform or associated patterns, and extrapolate if these patterns have Poisson, binomial or negative binomial distribution respectively. The results revealed the presence mainly of gastropods molluscs that would graze on benthic algae, these species have mainly aggregated pattern that has a robust negative binomial distribution pattern. The obtained results agree with observations for marine benthic fauna that mentioned the presence of aggregated pattern, has negative binomial distribution. Other ecological topics about spatial distribution were discussed.

The decapod fauna in the intertidal zone of the rocky shores of Chile is highly diverse, especially along the northern and central mainland coasts, where the influence of the cold Humboldt Current results in high productivity. One of the most abundant species in these ecosystems is the decapod Cyclograpsus cinereus Dana, 1851. The aim of the present study, carried out in the spring and summer seasons between 2018 and 2020, was to determine the spatial distribution patterns of the decapod C. cinereus in different sites along the rocky shores of Antofagasta bay, northern Chile, in order to establish probabilistic models that explain its distribution at each site. Individuals were counted in random quadrants in the intertidal zone. The data thus obtained were processed by application of the variance/mean ratio to determine whether the distribution of individuals was random, aggregated or uniform, associated with Poisson, negative binomial or positive binomial distributions, respectively. The data revealed aggregated (negative binomial) distribution in 15 sampling events, and uniform (positive binomial) distribution in 4 events. The sampling sites were located on rocky shores in four sectors of an urban zone, and two in a protected zone; no significant differences were found between the densities of the sites in the two zones. The results of the interpretative probabilistic models indicated aggregated distribution patterns, agreeing with previously reported interpretative probabilistic models for the distribution of decapods on the rocky shores of central and southern Chile.

Whether global latitudinal diversity gradients exist in rocky intertidal α-diversity and across functional groups remains unknown. Using literature data from 433 intertidal sites, we investigated α-diversity patterns across 155° of latitude, and whether local-scale or global-scale structuring processes control α-diversity. We, furthermore, investigated how the relative composition of functional groups changes with latitude. α-Diversity differed among hemispheres with a mid-latitudinal peak in the north, and a non-significant unimodal pattern in the south, but there was no support for a tropical-to-polar decrease in α-diversity. Although global-scale drivers had no discernible effect, the local-scale drivers significantly affected α-diversity, and our results reveal that latitudinal diversity gradients are outweighed by local processes. In contrast to α-diversity patterns, species richness of three functional groups (predators, grazers, and suspension feeders) declined with latitude, coinciding with an inverse gradient in algae. Polar and tropical intertidal data were sparse, and more sampling is required to improve knowledge of marine biodiversity.

The first representative of Tigriopus Norman, 1869 from the north-western Indian Ocean is described from rock pools on the Iranian coast. Tigriopus iranicus sp. nov. is distinguishable from its congeners by i) the possession of two maxillary endites, each with two setae; ii) a two-segmented mandibular endopod; iii) P1 enp-3 with one pinnate claw, a well-developed geniculate spine and a small seta; and iv) female P6 with two setae. Additionally, we present a complete redescription of Tigriopus raki Bradford, 1967 on the basis of paratype material and a key to the species of the genus. [ABSTRACT FROM AUTHOR]

Habitat characteristics and microhabitat of organisms pose a number of choices to foraging species, for example where and how to search for prey, which prey to select and what foraging technique to employ. Predators can enhance the profitability of foraging by adapting their strategies flexibly in relation to prey characteristics and environmental factors. To investigate the influence of rocky shore characteristics viz., condition of rock, position of limpet on the rock, stage of tide, and limpet opening technique of oystercatcher on the profitability of limpet foraging, a total of 193 attacks on limpets (Patella spp.) by Eurasian oystercatchers (Haematopus ostralegus) were made on Lundy Island, UK, using focal animal sampling. Multiple regression revealed that profitability was influenced by the condition of the rock and the limpet opening technique employed by oystercatchers. The profitability of the limpet opening technique appears to be associated with the condition of the rock. Oystercatchers forage by adapting their foraging strategy in accordance with the nature of the rocks i.e. wetness on which they are foraging. [ABSTRACT FROM AUTHOR]

In ecology, interaction networks allow the investigation of how interactions among species affect community structure and functioning. The structure of interaction networks can be nested and/or modular. Ecologically, the nested structure minimizes competition and increases the number of coexisting species, creating high diversity, while the modular structure occurs when there are non-overlapping groups of highly interacting consumer-resource species. Despite the importance of gastropod shells to hermit crabs, currently, few studies explored the structure of hermit crabs communities through a resource-usage perspective. Therefore, network analyses appear as an important tool to unveil how the use of empty shell as a resource rules hermit crabs communities through competition among species and rules hermit crabs populations through competition among distinct ontogenetic groups. This study investigated the resource usage pattern of empty gastropod shells by distinct ontogenetic stages of the hermit crab Calcinus tibicen from two different locations, using a network approach and the "Shell Adequacy Index" (SAI) analysis. The present results show that the interaction network between ontogenetic groups and gastropod shells was non-nested and modular and the SAI reflected the differences between males and ovigerous females in both locations, regarding shell size adequacy. We suggest that the modular structure may be a result of resource partitioning, which, in turn, is favored in habitats with a high degree of heterogeneity. The modular network structure may indicate habitat heterogeneity and resource partitioning. Future studies including other hermit crab species from the same areas should help determine how shells are partitioned interspecifically. [ABSTRACT FROM AUTHOR]

The acidification of samples for the simultaneous measurement of stable carbon (δ13C) and nitrogen (δ15N) isotopes represents an important methodological question still not clarified because the removal of calcium carbonate (CaCO3) from samples may affect the outcome of the stable-isotope analysis. We investigated the effect of acidification on samples of 25 different taxa of benthic marine organisms from a rocky shore, to determine whether acidification affects the isotopic values of δ13C and δ15N. After washing with distilled water and drying, each sample was divided into two parts; one part was acidified by adding 1 M HCl with a pipette, until no more CO2 was released, whereas the other part was retained as a non-acidified sample. Organisms with little CaCO3 showed no difference in carbon isotopic signatures after acidification, from those in the non-acidified part. Some organisms with a high CaCO3 content did show differences in carbon isotopic signatures after acidification. The nitrogen isotopic signature presented a significant difference; however, to what extent this difference is biologically important is discussed. Avoiding sampling parts containing a high concentration of carbonate is an efficient way to circumvent this problem. Acidification of samples as a pre-treatment for isotopic analysis is not useful for marine organisms without calcareous structures and is necessary only when the sampled parts contain significant amounts of carbonate. [ABSTRACT FROM AUTHOR]

Fossil bioerosion traces at a new site of Les Bez (Jura Department) and those already known from Verrières-de-Joux (Doubs Department) in the central French Jura record an ancient Miocene cliffed shoreline cut into Lower Cretaceous limestones. Both localities are at about 900 m above the present sea level. Caulostrepsis, Gastrochaenolites and Circolites are the ichnogenera identified at Les Bez, whereas only Gastrochaenolites is present at Verrières-de-Joux. This ichnoassociation identifies the Entobia ichnofacies, which corresponds to the upper infralittoral marine environment, biologically associated with the biocenosis of photophilic algae. By means of digital analysis of high-resolution field images, the percentage of the surface affected by the erosive activity of polychaete worms, bivalves and echinoids has been calculated. This information permits a better evaluation of their biological activity, thus complementing the data on the number of specimens per surface area. The cliff preserved at Les Bez was more affected, showing Gastrochaenolites with diameters smaller than those at Verrières. The Circolites–Caulostrepsis association is well developed at Les Bez, where polychaete borings are located within echinoid bowl-shaped pits with particular patterns, suggesting an ecological relationship between involved organisms. Moreover, the distribution of the borings along this outcrop is not uniform and digital analysis at three sections (A, B and C) suggests a lower and an upper zone developed on the outcrop under slightly different environmental conditions within the upper infralittoral. The exceptional preservation of the Les Bez fossil cliff-site demands protection in order to ensure its future existence and accessibility. [ABSTRACT FROM AUTHOR]

The role of habitat‐forming species in promoting biodiversity is widely acknowledged to vary across environmental gradients according to the extent to which they modify resources and environmental conditions. Population‐ and individual‐level traits of habitat‐forming species that influence species interactions may vary across gradients, but the importance of this indirect effect of environmental context is seldom considered. Here, we conducted surveys and field experiments to partition the effects of wave exposure on habitat‐provisioning for invertebrates by oysters into direct and indirect effects, arising from morphological variation of the oysters. A survey of nine sites with varying degrees of wave exposure in Port Jackson, Australia revealed a decline in oyster densities and surface area as wave energy increased. Correlated to declining oyster surface area was a decrease in the richness and abundance of associated invertebrates. By contrast, taxon diversity increased with increasing wave energy. Experimental deployments of oysters at high and low wave energy sites confirmed that variations in oyster morphology was a phenotypically plastic response to environmental conditions. Oyster recruitment was also lower at high as compared to low wave energy sites, further contributing to the variation in oyster habitat among sites. A colonisation experiment in which exposed and sheltered morphologies of oysters were deployed under high and low wave energy conditions in a fully orthogonal design found that invertebrate communities were influenced by both the wave energy of sites and by habitat structure. Our study suggests that in some instances the indirect effects of environment on habitat availability, arising from changes in habitat‐forming species density and morphology, may be as, or even more, important than the direct effects. Understanding how traits of habitat‐forming species respond to environmental conditions, and how intraspecific trait‐variation cascades to influence associated communities is critical to predicting when and where positive species interactions will be greatest. [ABSTRACT FROM AUTHOR]

Plastic pollution is an ever-increasing threat globally and poor waste management in South Africa has caused an increase in plastic leakage into the environment. Plastic waste in the environment are categorized according to size and plastic particles smaller than 5 mm in size are regarded as microplastics (MPs), and little to no research has been done on MPs pollution within the marine coastal environment and rocky shores in South Africa. Sampling was done in February 2020 at a rocky shore within Simon's Town Marina, Cape Town. MPs were extracted from collected water (n = 5), sediment (n = 5) and biota (n ≤ 30) samples. The extracted MPs were further classified based on shape, colour, size and an attenuated total reflectance Fourier-transform infrared (ATR-FTIR) instrument was utilized for polymer type identification The risks posed by MPs because of concentration at which they occurred and chemical composition were assessed in all the sample types. As expected, MPs were higher in sediment (38 ± 2 MP/kg) than in water (0.37 ± 0.06 MP/L) as the area has low water energy, allowing MP particles to settle within the sediment. Filter-feeding organisms had the lowest average MP particle concentrations (0.28 ± 0.04 MP/g) but displayed the highest variation of MP particle colours due to the non-selective feeding strategy, where other feeding strategies ingested mostly black/grey particles. The dominant MP size was between 100 μm and 500 μm in size for all samples combined, with the most abundant MP polymer type being nylon (27.27 %), polyethylene terephthalate (PET) (18.18 %) and natural MP particles such as cotton (18.18 %). The risk assessment indicated that polymer type poses a greater risk of MP pollution than MP concentrations., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 Published by Elsevier Ltd.)

The invasion history and current distribution of the alien marine mussel, the bisexual mussel Semimytilus algosus, on rocky shores of South Africa is described in this study. The eastern edge of its distribution has been monitored since 2014, and the most-recent observations were made between January and March of 2020, at 16 sites between Hondeklipbaai on the west coast and Nature's Valley on the south coast. From these 2020 records, the species ranged across approximately 840 km along the coast, from Hondeklipbaai to Hermanus. The species' invasion history and distribution suggests that this mussel has persisted on the west coast over the past decade, and spread along the coast in both northward and south–southeastward directions. Since 2010, the species has spread predominantly in a southerly and then easterly direction, extending its range by ∼270 km into the Agulhas ecoregion. In contrast, its spread has been slower to the north, with a range extension of only ∼75 km. Long-term, routine monitoring of the coast to track the spread of S. algosus and other invasive marine species, and to identify new incursions, is recommended to support evidence-based management of biological invasions. [ABSTRACT FROM AUTHOR]

Species, distribution, and adaptation of Nerita gastropods inhabiting a rocky shore ecosystem of Phuket Province were studied. The Nerites were recorded from 5 sampling sites; Pleumsuk beach, Nai yang beach, Por bay, Bangtao beach, and Yon bay. The sampling was done during October 2018 - January 2019. At each site, a line transect was set up perpendicularly to the coast. Three 50x50 cm quadrats were used to sample Nerites in every 2 m-long area along the line transect. Nerites were identified and counted, and their position was recorded. The present study identified 6 species of Nerita gastropods, namely N. albicilla, N. alveolus, N. chamealeon, N. costata, N. histrio and N. polita. The study site with the highest Shannon diversity index (H') was Nai yang beach (H' = 1.01), and the lowest was Pleumsuk beach (H' = 0.62). SØrensen similarity index (Cs) was highest between Nai yang beach and Pleumsuk beach. The species that showed widest distribution was N. chamealeon which was recorded at 5 sites, whereas N. histrio had the narrowest distribution and was recorded at only one site. At each site, N. alveolus inhabited locations closest to the highest tidal zone (0-16 meters), N. chamealeon and N. polita inhabited a lower zone (2-26 meters) (except for Por bay), and N. albicilla was mostly recorded far from the highest tidal zone (14 meters - the lowest tide). Other species were found in smaller numbers and no obvious distribution pattern was recognized. [ABSTRACT FROM AUTHOR]

Members of Clibanarius virescens show considerable intraspecific colour variation, including colouration of the second/third pereopods (green/white) and the dactyls of the second/third pereopods (with or without dark bands/patches). However, factors inducing these colour variations have not yet been elucidated. Here, we investigated the occurrence of colour variation in this species with particular emphasis on change of colouration associated with growth stage and region in specimens from tropical/subtropical to warm temperate areas in the Indo–West Pacific, including evidence from molecular phylogeny based on the cytochrome c oxidase subunit I (COI). We have, then, clarified that the colouration on the pereopod dactyls gradually changed from solid colour (yellow/white) to having dark-coloured area(s) or transverse band(s) as a result of the growth stage. The frequency of occurrence of the solid colour dactyls was higher than those of other colour types in tropical regions. Our results also indicated that the white ambulatory leg type was the colouration type that was frequently seen in juvenile stages. However, significant genetic differences were not detected between each colouration determined by molecular analysis of samples from 14 localities in the Indo-West Pacific region; in contrast, two genetically differentiated regional populations (North Australia; Phuket, Thailand; and Lombok, Indonesia) were detected. The present study, therefore, emphasizes the necessity for further study on the colour variation of marine animals focusing on growth stages and regional differences, with molecular data to facilitate the research on adaptation and/or speciation, especially in geographically widely distributed species. [ABSTRACT FROM AUTHOR]

The importance of herbivores and of plant diversity for community succession and recovery from disturbance is well documented. However, few studies have assessed the relative magnitude of, or potential interactions between, these factors. To determine the combined effect of herbivory and surrounding algal species richness on the recovery of a rocky intertidal community, we conducted a 27-month field experiment assessing algal recruitment and succession in cleared patches that mimic naturally forming gaps in the ambient community. We crossed two herbivore treatments, ambient and reduced abundance, with monocultures and polycultures of the four most common algal species in a mid-high rocky intertidal zone of northern California. We found that both the presence of herbivores and high surrounding algal richness increased recovery rates, and the effect of algal richness was twice the magnitude of that of herbivores. The increased recovery rate of patches containing herbivores was due to the consumption of fast-growing, early colonist species that preempt space from perennial, late-successional species. Mechanisms linking algal richness and recovery are more numerous. In polycultures, herbivore abundance and species composition is altered, desiccation rates are lower, and propagule recruitment, survival, and growth are higher compared to monocultures, all of which could contribute the observed effect of surrounding species richness. Herbivory and species richness should jointly accelerate recovery wherever palatable species inhibit late-successional, herbivore-resistant species and recruitment and survival of new colonists is promoted by local species richness. These appear to be common features of rocky-shore seaweed, and perhaps other, communities.

Background Dispersal is an important process affecting population dynamics and connectivity. For marine direct developers, both adults and juveniles may disperse. Although the distribution of juveniles can be initially constrained by their mothers’ choice, they may be able to leave the parental habitat and colonize other habitats. We investigated the effect of habitat quality, patch size and presence of conspecific adults on the colonization of novel habitats by juveniles of the tube-dwelling amphipod Cymadusa filosa associated with the macroalgal host Sargassum filipendula. Methods We tested the factors listed above on the colonization of juveniles by manipulating natural and artificial plants in both the field and laboratory. Results In the laboratory, juveniles selected high-quality habitats (i.e., natural alga), where both food and shelter are provided, when low-quality resources (i.e., artificial alga) were also available. In contrast, habitat quality and algal patch size did not affect the colonization by juveniles in the field. Finally, the presence of conspecific adults did not affect the colonization of juveniles under laboratory condition but had a weak effect in the field experiment. Our results suggest that C. filosa juveniles can select and colonize novel habitats, and that such process can be partially affected by habitat quality, but not by patch size. Also, the presence of conspecifics may affect the colonization by juveniles. Successful colonization by this specific developmental stage under different scenarios indicates that juveniles may act as a dispersal agent in this species.

Abstract Seaweed aggregates form secondary substrates on rocky shores, providing habitats for phytal organisms such as the spider crab Epialtus brasiliensis Dana, 1852. This species is one of the most abundant macroinvertebrate component from seaweed communities. Although the literature suggests that E. brasiliensis lives in many species of seaweed, their density has only been reported in communities of Sargassum spp. This study assessed the density of the spider crab E. brasiliensis associated with the seaweed Sargassum cymosum Agardh, 1820, Hypnea musciformis (Wulfen) Lamouroux and Acanthophora spicifera (Vahl) Borgesen. We expected to observe a higher density of E. brasiliensis in S. cymosum, which shows greater morphological complexity, followed by H. musciformis, with intermediate complexity, and then by A. spicifera, with low complexity. We found that the density of these crabs can be as abundant in H. musciformis as has been previously reported for S. cymosum, but in both species, the density was higher than in A. spicifera. Overall, our findings improve the knowledge of the phytal habitats used by E. brasiliensis in rocky shore environments.

Anticipatory changes in organismal responses, triggered by reliable environmental cues for future conditions, are key to species' persistence in temporally variable environments. Such responses were tested by measuring the physiological performance of a tropical high-shore oyster in tandem with the temporal predictability of environmental temperature. Heart rate of the oyster increased with environmental temperatures until body temperature reached ∼37°C, when a substantial depression occurred (∼60%) before recovery between ∼42° and 47°C, after which cardiac function collapsed. The sequential increase, depression, and recovery in cardiac performance aligned with temporal patterns in rock surface temperatures, where the risk of reaching temperatures close to the oysters' lethal limit accelerates if the rock heats up beyond ∼37°C, coinciding closely with the body temperature at which the oysters initiate metabolic depression. The increase in body temperature over a critical threshold serves as an early-warning cue to initiate anticipatory shifts in physiology and energy conservation before severe thermal stress occurs on the shore. Cross-correlating the onset of physiological mechanisms and temporal structures in environmental temperatures, therefore, reveals the potential role of reliable real-time environmental cues for future conditions in driving the evolution of anticipatory responses. [ABSTRACT FROM AUTHOR]

The rocky shores in Chile have a wide invertebrate species diversity, that include species with marked abundances in determined regions. The aim of the present study is to analyse the spatial distribution pattern in different marine invertebrate species in rocky shore of Araucania region, considering if these species have random, uniform or associated patterns, and extrapolate if these patterns have Poisson, binomial or negative binomial distribution respectively. The results revealed the presence mainly of gastropods molluscs that would graze on benthic algae, these species have mainly aggregated pattern that has a robust negative binomial distribution pattern. The obtained results agree with observations for marine benthic fauna that mentioned the presence of aggregated pattern, has negative binomial distribution. Other ecological topics about spatial distribution were discussed. As costas rochosas no Chile têm uma ampla diversidade de espécies de invertebrados, que incluem espécies com abundância marcada em determinadas regiões. O objetivo do presente estudo é analisar o padrão de distribuição espacial em diferentes espécies de invertebrados marinhos na costa rochosa da região de Araucanía, considerando se essas espécies possuem padrões aleatórios, uniformes ou associados, e extrapolar se esses padrões possuem distribuição binomial de Poisson, binomial ou negativa. respectivamente. Os resultados revelaram a presença principalmente de moluscos gastrópodes que pastam em algas bentônicas, estas espécies têm principalmente agregado padrão que tem um padrão robusto de distribuição binomial negativa, padrão agregado de grupos, e a fauna de água doce que apresenta distribuição binomial negativa. Outros tópicos ecológicos sobre distribuição espacial foram discutidos. [ABSTRACT FROM AUTHOR]

Polychaetes are one of the most important groups of macrobenthic organisms in coastal and marine environments, in terms of diversity and abundance, and play an important role in the functioning of ecosystem. This study aims to describe the structure and spatial distribution of polychaete communities along Essaouira's rocky shoreline (Atlantic coast of Morocco) in relation to the major environmental variables such as granulometry, salinity, temperature, pH, and intertidal range. Twelve sites from these intertidal rocky shores were sampled using a quadrat method during the summer 2016. A total of 4 435 individuals belonging to 34 taxa were recorded. Among the families, Sabellaridae (24%) and Nereididae (23%) were ranked first in terms of abundance of individuals. Sabellaria alveolata (24%) and Perinereis cultrifera (13%) were the dominant species. Diversity (H′) values varied from 2.28 to 3.95. Pielou's index (J′) varied between 0.62 and 0.89. This was essentially due to the low dominance of few species. Cluster analysis was used to characterise Essaouira's rocky shores on the basis of benthic polychaete communities. SIMPER analysis confirmed the presence of three distinct communities. According to canonical correspondence analysis, the structure and distribution of faunal assemblages of benthic polychaetes was mainly related to topographical complexity, water temperature, hydrodynamic conditions and upwelling. We conclude that these rocky shores show typically high benthic polychaete diversity compared to the taxonomic list of other rocky coasts. In addition, these results constitute a baseline data for the development of a sustainable network for long-term monitoring of benthic polychaete community changes due to ecological factor influences and anthropogenic activity impacts. [ABSTRACT FROM AUTHOR]

Limpets and barnacles are important components of intertidal assemblages worldwide. This study examines the effects of barnacles on the foraging behaviour of the limpet Patella vulgata , which is the main algal grazer in the North-west Atlantic. The behaviour of limpets on a vertical seawall on the Isle of Man (UK) was investigated using autonomous radio-telemetry, comparing their activity patterns on plots characterized by dense barnacle cover and plots from which the barnacles had been removed. Limpet behaviour was investigated at mid-shore level, but two different elevations were considered. This experiment revealed a significant effect of barnacle cover on the activity of P. vulgata. Limpets on smooth surfaces spent a greater proportion of total time active than did limpets on barnacles. Movement activity was also greater in areas that were lower down in the tidal range. In general, limpets were either predominantly active during diurnal high or nocturnal low tides and always avoided nocturnal high tides. Individuals on barnacles at the higher elevation concentrated their activity during nocturnal low water. All the other groups of limpets (smooth surfaces on the upper level and all individuals on the lower shore) had more excursions centred around daylight hours with an equal distribution of activity between periods of low and high water. Inter-individual variability was, however, pronounced. [ABSTRACT FROM AUTHOR]

This work shows evidence of complete encapsulated development of Onchidella marginata for the first time in South America. Recent common ancestry was suggested for geographically separated New Zealand sub-Antarctic and South American populations of Onchidella. This could be explained as driven by passive rafting mediated by circumpolar ocean currents. In samples from mussel- and algal-beds in intertidal rocky shores from the southern tip of South America (Tierra del Fuego Island, Argentina) we found both adults and egg masses, and crawling hatchlings were observed. [ABSTRACT FROM AUTHOR]

Paracentrotus lividus is a sea urchin widely distributed throughout Mediterranean basin and Atlantic coast, highly appreciated for its gonads. It is broadly distributed along the Portuguese coast and its exploitation has potential to grow. Nevertheless, fluctuations on nutritional composition and sensory traits of P. lividus according to each habitat and seasonality are still little understood. Stable isotopes analysis has been recognised as a powerful tool for exploring environmental-ecological-biological processes in aquatic systems. It is also useful to give indications on how to improve available diets for the aquaculture of this species, contributing to a sustainable rearing. Herein, such technique was used to assess temporal and spatial differences in isotopic composition of P. lividus' gonads and intestines and to evaluate its application as a management tool for the identification of the most suitable locations and periods of the year to collect organisms with high quality gonads. Sampling campaigns were carried out between 2019 and 2020 in five rocky shores along the Portuguese coast (Viana do Castelo, Figueira da Foz, Peniche, Sines and Guia). Three rock pools were selected in each shore, and five specimens were collected per pool. The gonadosomatic index (GSI, %) was calculated and carbon and nitrogen elemental and isotopic composition were determined in gonads and intestine using isotope ratio mass spectrometry. Significant spatial and temporal fluctuations were registered among urchins collected along Portuguese coast. Such variations may be associated with latitudinal gradients along the coast and variations of environmental and ecological conditions within each area, especially those affecting algal biomass, on which urchins primarily feed. More research must be pursued to maximise the use of stable isotopes analysis as a management tool for supporting sustainable exploitation of natural stocks or even to contribute to nutritional studies with new diets for sea urchin production that consider the feeding of these animals in the wild. [Display omitted] • Significant spatial and temporal fluctuations found. • A north to south pattern registered along the Portuguese coast. • Elemental/isotopic composition analysis as a quality indicator of commercialised sea urchins. [ABSTRACT FROM AUTHOR]

Examining changes in abundance and demographic rates at species distribution margins may provide the first signs of broader species responses to environmental change. Still, the joint impact of space and time have remained relatively unstudied in most marginal regions. In order to examine the influence of climate variability on mussel distribution patterns, we monitored three sublittoral and marginal blue mussel (Mytilus trossulus) populations, spaced along a salinity gradient. Densities and biomasses peaked toward the saltier parts of the study area and showed relatively larger variations toward the low saline edge. Temporally, the areas showed a consistent increase in abundance after a synchronized large-scale recruitment event, which was followed by a decline in population size, occurring much faster toward the very range edge. Salinity, temperature, winter severity, and wave exposure explained most of the spatiotemporal variation in mussel abundances and adults showed positive effects on recruit abundance. We show empirically that the dynamics of edge populations are not driven by large changes in climate variables but that small spatial and temporal changes in key environmental variables have large and non-linear population level effects. Our results also show that fluctuating recruitment is a key factor for population stability affecting the storage potential of marginal populations, which dramatically decrease toward the edge. Our study provides a window into future population patterns and processes that drive marginal mussel populations in an altered sea characterized by rising temperature and declining salinity.

How intertidal species survive their harsh environment and how best to evaluate and forecast range shifts in species distribution are two important and closely related questions for intertidal ecologists and global change biologists. Adaptive variation in responses of organisms to environmental change across all levels of biological organization - from behavior to molecular systems - is of key importance in setting distribution patterns, yet studies often neglect the interactions of diverse types of biological variation (e.g. differences in thermal optima owing to genetic and acclimation-induced effects) with environmental variation, notably at the scale of microhabitats. Intertidal species have to cope with extreme and frequently changing thermal stress, and have shown high variation in thermal sensitivities and adaptive responses at different levels of biological organization. Here, I review the physiological and biochemical adaptations of intertidal species to environmental temperature on multiple spatial and temporal scales. With fine-scale datasets for the thermal limits of individuals and for environmental temperature variation at the microhabitat scale, we can map the thermal sensitivity for each individual in different microhabitats, and then scale up the thermal sensitivity analysis to the population level and, finally, to the species level by incorporating physiological traits into species distribution models. These more refined mechanistic models that include consideration of physiological variations have higher predictive power than models that neglect these variations, and they will be crucial to answering the questions posed above concerning adaptive mechanisms and the roles they play in governing distribution patterns in a rapidly changing world., Competing Interests: Competing interests The author declares no competing or financial interests., (© 2023. Published by The Company of Biologists Ltd.)

The coastal marine ecosystems in Easter Island have been poorly studied, and the main studies were isolated species records based on scientific expeditions. The aim of the present study is to apply a spatial distribution analysis and niche sharing null model in published data on intertidal marine gastropods and decapods in rocky shore in Easter Island based in field works in 2010, and published information from CIMAR cruiser in 2004. The field data revealed the presence of decapods Planes minutus (Linnaeus, 1758) and Leptograpsus variegatus (Fabricius, 1793), whereas it was observed the gastropods Nodilittorina pyramidalis pascua Rosewater, 1970 and Nerita morio (G. B. Sowerby I., 1833). The available information revealed the presence of more species in data collected in 2004 in comparison to data collected in 2010, with one species markedly dominant in comparison to the other species. The spatial distribution of species reported in field works revealed that P. minutus and N. morio have aggregated pattern and negative binomial distribution, L. variegatus had uniform pattern with binomial distribution, and finally N. pyramidalis pascua, in spite of aggregated distribution pattern, had not negative binomial distribution. Finally, the results of null model revealed that the species reported did not share ecological niche due to competition absence. The results would agree with other similar information about littoral and sub-littoral fauna for Easter Island. [ABSTRACT FROM AUTHOR]

Many studies have already assessed how wave action may affect morphology of intertidal species among sites that vary in wave exposure, but few attempted to look to this issue in smaller scales. Using the most common limpet of the Brazilian coast, Lottia subrugosa , and assuming position on rocky boulders as a proxy for wave action at small scale, we tested the hypothesis that waves may also influence limpet morphology at a smaller spatial scale by investigating how individual size, foot area and shell shape vary between sheltered and exposed boulder sides on three shores in the coast of Ubatuba, Brazil. Limpets consistently showed a proportionally larger foot on exposed boulder sides for all shores, indicating that stronger attachment is an important mechanism to deal with wave action dislodgement at a smaller scale. Shell shape also varied in the scale investigated here, with more conical (dissipative) shells occurring in exposed boulder sides in one exposed shore across time and in the other exposed shore in one year. Shell shape did not vary regarding boulder sides across time in the most sheltered shore. Although we did not assess large spatial scale effects of wave action in this study, variations of the effect of waves at small spatial scale observed for shell shape suggest that it may be modulated by the local wave exposure regime. Our work highlights the importance of wave action at small spatial scales, and may help to understand the ecological variability of limpets inhabiting rocky shores. [ABSTRACT FROM AUTHOR]

• Rocky shores on the Navarino Island showed a higher taxa richness and wet biomass in summer than winter, but the significance of seasonal variations varied in each intertidal site. One of the main causes of these variations was due to the rapid growth of seasonal algae during summertime (Adenocystis utricularis). • The seasonal changes of taxa richness and wet biomass did not show significant differences in all sites and intertidal levels. This is likely caused by the abundance of temporally-persistent algae. • We propose that coupled factors such as light, nutrient availability, sea surface temperature, relative humidity and species composition would play a fundamental role in the productivity of the macroalgae assemblages on the rocky shores of high latitudes along the southern tip of South America. The Magellanic Sub-Antarctic Channels ecoregion supports one of the greatest number of macroalgae species in South America. In this ecoregion, the majority of macroalgae research has been associated with spatial ecology. In contrast, the temporal scale has received little attention. Here, we report the seasonal changes of taxa richness, wet biomass and assemblage structure for intertidal macroalgae in Robalo Bay (55 °S), situated within the Cape Horn Biosphere Reserve. Overall, forty-nine macroalgae taxa were identified. We found a higher taxa richness and wet biomass in the summer than in the winter, but the strength of seasonal variations varied spatially across intertidal sites and levels. A similar seasonal pattern was detected with multivariate analysis. The seasonal changes are explained by the rise of seasonal algae such as Adenocystis utricularis. In turn, we found temporally-persistent algae such as Ceramium virgatum and Nothogenia fastigiata which did not show sharp seasonal variation. In conclusion, we suggest that macroalgal seasonality might be strongly modulated by coupled factors such as light, nutrient availability, sea surface temperature, relative humidity, and species composition. These factors would support an increase of taxa richness and wet biomass in the summertime on the rocky shores in high latitudes of South America. [ABSTRACT FROM AUTHOR]

Species of hermit crabs in the genus Clibanarius Dana, 1852 have adapted to various environments in the intertidal areas, including hard substrates and soft sediments. These species often bear a close morphological resemblance to each other, therefore, the colouration on the pereopods can be one of the reliable characteristics to distinguish the species. However, the evolutionary relationships among species with different colour patterns and relationships between colour patterns and habitat adaptation have not previously been investigated. Therefore, we reconstructed the phylogenetic relationships among 19 species of Clibanarius based on mitochondrial [12S rRNA, 16S rRNA and cytochrome oxidase I] and nuclear [histone H3] DNA markers. The results suggest that the striped and solid colour elements have evolved multiple times independently, with the ancestral colour pattern potentially being scattered, bright colour spots with a bright colour band. Our findings also suggest that evolutionary adaptation from hard substrates to mudflats and soft sediments may have occurred at least twice. [ABSTRACT FROM AUTHOR]

Predicting the spread of invasive species in a warming world calls for a better understanding of the mechanisms behind the relative performance of both invasive and indigenous species as recipient communities can offer biotic resistance. A particularly important functional trait in this context is reproductive potential. The Mediterranean mussel Mytilus galloprovincialis is invasive world-wide and threatens the native brown mussel Perna perna on South African rocky shores. Where they co-exist, Mytilus dominates the high and Perna the low mussel zone, overlapping in the middle. Mytilus generally exhibits high individual reproductive output, but feeding time is reduced, physical conditions are stressful and adult densities are lower on the higher shore. We compared overall reproductive potential of populations of the two species using a 1-year data set for three sites, accounting for within-shore distribution and abundances. Despite the restriction of Mytilus to the more stressful upper-shore, its aggregate reproductive potential was comparable to that of Perna. We then used Dynamic Energy Budget modelling to test the effects of changing conditions by calculating aggregate reproductive potential under temperature conditions predicted for the end of the century by the International Panel on Climate Change. The results suggest increased aggregate reproductive potential for both species, but the effect was stronger for the native species at two of three sites, implying increased biotic resistance by Perna to the further spread of Mytilus. Combining ecological context and physiological performance elucidates how interactions between native and invasive species may alter. Such nuances are fundamental to anticipating winners or losers in a world where distribution shifts are increasingly common. [ABSTRACT FROM AUTHOR]

Hard bottoms can negatively affect the surrounding infauna by hosting predatory fauna and modifying local hydrodynamics and sedimentation rates. Considering that these effects depend on the distance to the hard bottoms, we expected that the infaunal structure and recolonization would change accordingly. We assessed whether the distance from a rocky shore alters infaunal recolonization in a subtropical tidal flat. Sediment was defaunated on sites near and far from a rocky shore and the subsequent faunal recolonization was followed for 40 days. The sites near and far from the rocky shore displayed different assemblage structures, which we attributed to local variation in hydrodynamic conditions. Both the total infaunal abundance and the abundance of the dominant species recovered faster at the near site. We indicate that changes in infaunal recolonization at varying distances from natural rocky shores are primarily driven by the availability of adults. Infaunal recovery took less than 2 weeks, but recolonization rates increased near the rocky shore, as a function of its naturally variable assemblage structure and relatively lower species richness and abundances. We suggest that models of infaunal distribution and recolonization should incorporate landscape features such as the presence and distance from rocky bottoms. [ABSTRACT FROM AUTHOR]

Dispersal and colonization processes are complex and affected by several factors in the marine realm. Understanding how and where individuals go can be challenging, particularly for marine invertebrates that do not have a sessile phase. We selected the amphipod-macroalga system to investigate if life stage and life style can influence colonization patterns from algal patches placed at different distances and having variable amounts of available substrate for colonization. Amphipods are key organisms connecting the benthonic and pelagic environments through food chains and our results bring important contributions for conservation and management of these systems in shallow marine areas. We ran field and laboratory experiments to compare the colonization of Sargassum fronds between adult and juvenile amphipods, as well as tube-dwelling and free-living species. We found three times more juveniles than adults colonizing the experimental patches, and both tube-dwelling and free-living juveniles occupied experimental patches across all distances in the field. In the laboratory, we observed the tube-dwelling Cymadusa filosa remaining in more proximal patches than the free-living Hyale niger. Juveniles occupied similarly small and large algal surface area patches both in the field and in the laboratory, while adults occupied primarily large algal surface area patches in the field. We did not observe differences regarding life style in the colonization of small or large algal surface area patches by juveniles in the field or in the laboratory. Our findings support the idea that juvenile amphipods may have higher dispersal potential by colonizing more distant areas and/or patches with variable amounts of available substrate when compared to adults. Amphipods life style may influence colonization distance during initial dispersal movements of juveniles due to the fact that tube-dweller juveniles stay closer to the site where they were released. • Juvenile amphipods may have higher dispersal potential • Amphipods life style may influence colonization distance • Variation on patterns of colonization of macroalgae by amphipods between life stage and life style [ABSTRACT FROM AUTHOR]

Aim: Climate change is predicted to alter the distribution and abundance of marine species, including canopy‐forming seaweeds which provide important ecosystem functions and services. We asked whether continued warming will affect the distribution of six common canopy‐forming species: mid‐intertidal fucoids (Ascophyllum nodosum,Fucus vesiculosus), low‐intertidal Irish moss (Chondrus crispus), subtidal laminarian kelps (Saccharina latissima,Laminaria digitata) and the invasive Codium fragile. Location: Northwest Atlantic. Methods: We used occurrence records and the correlative presence‐only species distribution model Maxent to determine present‐day distribution. This distribution was compared to each species' warm‐water physiological thresholds indicating areas of stable or reduced growth and mortality. Present‐day models were then projected to mid‐century (2040–2050) and end‐century (2090–2100) using two contrasting carbon emission scenarios (RCP2.6 and 8.5) and two global climate models from CMIP5 based on changes in ocean temperatures. Results: Projected range shifts were minimal under low emissions (RCP2.6), but substantial species‐specific range shifts were projected under high emissions (RCP8.5), with all species except C. fragile predicted to experience a northward shift in their southern (warm) edge of ≤406 km by the year 2100. Northward expansions outweighed southern extirpations for fucoids and C. crispus leading to overall range expansions, while range contractions were projected for kelps and C. fragile. Model projections generally agreed with physiological thresholds but were more conservative suggesting that range shifts for kelps may be underpredicted. Main conclusions: Our results highlight the benefits to be gained from strong climate change mitigation (RCP2.6), which would limit changes in rocky shore community distribution and composition. The business‐as‐usual RCP8.5 scenario projected major range shifts, seaweed community reorganization and transitions in dominant species south of Newfoundland by 2100 (~47°N). As canopy‐forming seaweeds provide essential habitat, carbon storage, nutrient cycling and commercial value, understanding their response to continued climate warming is critical to inform coastal management and conservation planning. [ABSTRACT FROM AUTHOR]

Loss of habitat is a global threat to biodiversity. Habitat-forming species in particular are shifting their distribution at local and regional scales, changing habitat aspect globally. In temperate intertidal rocky shores, this poleward shift of canopy-forming seaweeds is leading to a shift to mat- or turf-dominated communities. These changes and their consequences are poorly understood and can vary globally. Most studies, however, have focused on local and regional processes. Using rocky low intertidal algal-dominated systems, this study aims to understand the independent role of a rich understory vegetation layer formed by cespitose algae as community drivers. Moreover, the study aimed to understand whether the observed patterns can be consistent over spatial regions, thus three distinct regional zones of the North Atlantic (Eastern shores of Nova Scotia, Canada; the Poitou-Charentes coast, France; the Eastern shores of Northern Ireland, UK) were sampled as part of this study. From surveys, results showed that in the intertidal zone with low desiccation potential, canopies generally do not drive understory cespitose species richness or distribution. Cespitose algae on the other hand positively influenced richness in all regions. Community composition was also influenced by cespitose algal species, which increased the number of mobile epifauna species, while decreasing the number of encrusting epifauna species. This has wide implications: (i) understory species that are often overlooked may play a primary role as habitat formers; (ii) understory species may help maintain biodiversity in a changing world where primary species distribution is shifting. [ABSTRACT FROM AUTHOR]

1. Echthrodesis lamorali Masner, 1968 is the only known parasitoid of the eggs of the intertidal rocky shore spider Desis formidabilis O.P. Cambridge 1890 and is endemic to a small area of South Africa. 2. The abundance of spider nests and parasitoid presence were assessed in relation to their in‐ and between‐shore location at multiple sites within the distribution of E. lamorali along the Cape Peninsula (Western Cape, South Africa). 3. Desis formidabilis nests were more abundant in the mid‐shore zone than higher up or lower down the shore. Spider population sizes also differed between collection sites, with higher numbers recorded on the cooler western coast of the peninsula. 4. Evidence of parasitoid activity was recorded in 43.31% of the 127 nests and 13.85% of the 592 egg sacs they contained. 5. Where parasitoids gained entry to a spider egg sac, oviposition took place into all of the eggs present. 6. Incidence of wasp activity was positively correlated with spider nest concentration, not with height up the shore, suggesting that both the host and parasitoid are tolerant of salt‐water inundation. 7. These results should assist managers of the Table Mountain National Park, in which the full distribution of E. lamorali falls, to better understand this component of rocky shore community dynamics. Echthrodesis lamorali Masner, 1968 is the only known parasitoid of the eggs of the intertidal rocky shore spider Desis formidabilis O.P. Cambridge 1890 and is endemic to a small area of South Africa.Desis formidabilis nests were more abundant in the mid‐shore zone than higher or lower up the shore, as well as on the cooler western coast of the Cape Peninsula.Evidence of parasitoid activity was recorded in 43.31% of the 127 nests and 13.85% of the 592 egg sacs they contained, and parasitism showed a density‐dependent relationship with the host. [ABSTRACT FROM AUTHOR]

Warming, nutrient enrichment and biodiversity modification are among the most pervasive components of human‐induced global environmental change. We know little about their cumulative effects on ecosystems; however, even though this knowledge is fundamental to predicting and managing their consequences in a changing world. Here, we show that shifts in predator species composition can moderate both the individual and combined effects of warming and nutrient enrichment in marine systems. However, all three aspects of global change also acted independently to alter different functional groups in our flow‐through marine rock‐pool mesocosms. Specifically, warming reduced macroalgal biomass and assemblage productivity, whereas enrichment led to increased abundance of meso‐invertebrate consumers, and loss of predator species led to increased gastropod grazer biomass. This disparity in responses, both across trophic levels (macroalgae and intermediate consumers), and between detecting additive effects on aggregate measures of ecosystem functioning, yet interactive effects on community composition, illustrates that our forecasting ability depends strongly on the level of ecological complexity incorporated within global change experiments. We conclude that biodiversity change—and loss of predator species in particular—plays a critical and overarching role in determining how ecological communities respond to stressors. Warming, nutrient enrichment and biodiversity loss are among the most pervasive components of human‐induced global change, yet we know little about their cumulative effects on ecosystems. We show that biodiversity change, and loss of predators in particular, plays a critical and overarching role in determining how ecological communities respond to stressors. [ABSTRACT FROM AUTHOR]

Research on physical ecosystem engineering—i.e., the structural modification of environments by organisms—has flourished during the last two decades. At present, the importance of physical ecosystem engineers for the biodiversity and the functioning of ecosystems is well recognized by scientists. This Special Issue contains fifteen papers that illustrate the diversity of physical ecosystem engineering processes that occur in the world coastal habitats—from coastal dunes to the shallow subtidal zone. It includes 2 reviews comparing ecosystem engineering attributes and impacts across taxa and 13 case studies that inform our general understanding of the variation in engineering impacts, compound engineering effects, novel engineering interactions, and engineered structural legacies.