Shore Communities Research Articles

Anthropogenic stressors and rocky shore communities along Atlantic Patagonia: The need of including coastal biodiversity in marine protected areas planning

Abstract The conservation of marine ecosystems depends on the establishment and functioning of marine protected areas (MPAs). These areas are not exempt from the effects generated by a variety of anthropogenic stressors. Coastal biodiversity can provide key information of MPAs health; however, it is not usually considered in MPAs planning process, particularly in the Southwestern Atlantic. In this work, we provide an analysis and discussion of the anthropogenic stressors and the rocky intertidal biodiversity parameters occurring along 10 latitudinal degrees within the major MPAs of the continental Patagonia (Argentina). Specifically, we studied the intensity of 10 social, economic and environmental marine‐related anthropogenic stressors and characterized the intertidal biodiversity (biomass, density and size of scorched mussels and its associated communities) in the mid intertidal rocky shore. We found that most of the anthropogenic stressors studied had some level of intensity at all MPAs in Patagonia. In addition, each MPA has unique biodiversity assemblages. Total anthropogenic stress was not directly correlated with the mussel bed parameters or the richness of the associated fauna. Artisanal fisheries, tourism, invasive species and trampling were found to have the highest intensity on the MPAs. Moreover, a negative relation between artisanal fisheries, tourism and invasive species and the biomass and size of mussels was found, along with a negative relation between tourism and density. Furthermore, three MPAs registered the greatest anthropogenic pressure. Our study evidence that although Argentina has significantly advanced in the creation of MPAs in the last decades, the objectives for the conservation of the ecosystems are still narrow. Our results highlight that globally, MPAs need to include the perspective of coastal intertidal biodiversity and their stressors in their management strategies. By doing this, it will contribute to have a more holistic approach and thus it will improve MPAs conservation efforts.

Investigating the interactive effects of habitat type and light intensity on rocky shores

Light availability and habitat complexity are two key drivers of community assembly. Urbanisation has been shown to affect both, with important consequences to ecological communities. On the intertidal, for instance, studies have shown that light intensity is greater on natural rocky shores than on less complex artificial habitats (seawalls), though different habitats can also experience similar light intensities, for example when shaded by urban structures. Understanding therefore how these factors individually, and combined, affect communities is important to understand the mechanisms driving changes in community structure, and consequently provide solutions to tackle the increasing homogenisation of habitats and lightscapes in urbanised spaces through smart infrastructure designs. Here, we assessed how different light levels affect the recruitment of communities in rock pools and on emergent rock on an intertidal rocky shore. We cleared 30 patches of emergent rock and 30 rock pools and manipulated light using shades with different light transmissions (full light, procedural control, 75%, 35%, and 15% light transmission, full shade) and assessed mobile and sessile communities monthly for 6 months. Effects of reducing light levels were generally stronger on rock than in pools. Fully shaded plots supported double the amount of mobile organisms than plots in full sunlight, in both habitats. Algal cover was higher in pools compared to rock, and at intermediate light levels, but effects varied with site. This study highlights the importance of variable light conditions and different habitats for rocky shore communities, which should be considered in future coastal developments to retain natural biodiversity.

Predicted ecological consequences of wave energy extraction and climate-related changes in wave exposure on rocky shore communities

Abstract Wave energy has the potential to contribute in the transition to decarbonized electricity generation. Extracting wave energy might be expected to have ecological impacts on rocky shore intertidal communities where exposure is one of the most important factors determining species structure and composition. With global climatic change, coastal exposure is predicted to increase with greater significant wave height. The wave-exposed west coast of Orkney, Scotland, UK, is the site of pre-commercial wave device testing. Surveys of 39 rocky shore sites along this coast identified key species and abundances, and quantified exposure-modifying topographic variables. A spectral wave model was constructed to compare baseline, wave extraction, climate change, and combined scenarios. Generalized additive modelling was used to describe the relationship between species, topography, and exposure. Results show that individual species differentially respond to exposure changes with ‘winners’ and ‘losers’ at site level. Overall, community responses are expected to be far greater following predicted climatic change than to industrial-scale wave energy extraction, depending on spatial scale. In combination, energy extraction may reduce the effects of climate-change-related increases in wave exposure of rocky shores. Predicting how location-specific biotic assemblages respond to changes in wave energy as a result of long-term forcing agents provides a valuable marine resource management tool.

Environmental factors have stronger effects than biotic processes in patterns of intertidal populations along the southeast coast of Brazil

Rocky shore communities are shaped by complex interactions among environmental drivers and a range of biological processes. Here, we investigated the importance of abiotic and biotic drivers on the population structure of key rocky intertidal species at 62 sites, spanning ∼50% of the Brazilian rocky shoreline (i.e., ∼500 km). Large-scale population patterns were generally explained by differences in ocean temperature and wave exposure. For the gastropod species Lottia subrugosa, differences at smaller scales (i.e., 0.1–1 km) were better explained by other abiotic influences such as freshwater discharge and substrate roughness. Based on the general population patterns of intertidal species identified, three main oceanographic groups were observed: a cold-oligotrophic grouping at northern sites (Lakes sub-region), a eutrophic group associated with large estuaries and urban zones (Santos and Guanabara bays); and a transitional warm-water group found between the two more productive areas. Larger individuals of Stramonita brasiliensis, L. subrugosa and Echinolittorina lineolata were generally found in the cold-oligotrophic system (i.e., upwelling region), while small suspension feeders dominate the warm-eutrophic systems. Evidence of bottom-up regulation was not observed, and top-down regulation effects were only observed between the whelk S. brasiliensis and its mussel prey Pernaperna. Environmental drivers as compared to biotic interactions, therefore, play a key role determining the population structure of multiple intertidal species, across a range of spatial scales along the SW Atlantic shores.

Species contributions to ecosystem stability change with disturbance type

Simultaneous exposure to multiple stressors complicates the challenge of predicting ecological responses to global environmental change. Here, we show that the contributions of individual species and functional groups to the overall stability of ecosystems can be modified by the presence of different stressors, both individually and in combination. By disturbing natural rocky shore communities with nutrients and sediments and simulating extinction of predatory whelks and grazers, we also found that consumers can simultaneously stabilise and destabilise communities along different stability dimensions, irrespective of their trophic position. Our results suggest that our experimental disturbances influenced consumer contributions to stability indirectly by modifying the interactions between consumers and macroalgae in different ways. These findings merit further exploration in different systems exposed to a range of different stressors to better understand how perturbations of different kinds can modify the multifaceted contributions of species to the overall stability of ecosystems.

Effects of harvesting and an invasive mussel on intertidal rocky shore communities based on historical and spatial comparisons.

Intertidal rocky shores are the most accessible marine habitats and therefore heavily impacted by harvesting. In recent years, they have also been increasingly invaded by alien species, which compounds the effects of harvesting on rocky shore community composition and functioning. Recent survey data, combined with historical data from 1970, were used to assess temporal changes over the intervening period in rocky shore communities at two sites (Wireless Point and Wireless Island). Three kinds of changes emerged: (1) the appearance of alien species; (2) the effects of increased harvesting pressure; and (3) the direct and indirect effects of these changes on other species. A striking result was transformation of mid-shore zones on exposed shores by the appearance of the invasive Mediterranean mussel Mytilus galloprovincialis, and the indirect effects of this on the demography and vertical zonation patterns of the granular limpet Scutellastra granularis. Adult limpets have become excluded by the mussel, whereas juveniles find a secondary home on the shells of the mussel and their abundance has increased. To further disentangle the effects of harvesting from those of alien invasions, a spatial comparison was made between two currently unharvested no-take sites (Scarborough South and Scarborough North) and two regularly harvested sites (Kommetjie and Wireless Point). Harvesting has substantially depleted the granite limpet Cymbula granatina and Argenville's limpet Scutellastra argenvillei. This has led to the proliferation of opportunistic seaweeds, such as Ulva spp. The dual effects of alien invasive species and over-harvesting have major ecosystem effects but do not necessarily diminish biodiversity because the alternative habitats that have developed provide opportunities for colonisation by additional species.

Stabilizing effects of spatially heterogeneous disturbance via reduced spatial synchrony on a rocky shore community.

Understanding how synchronous species fluctuations affect community stability is a main research topic in ecology. Yet experimental studies evaluating how changes in disturbance regimes affect the synchrony and stability of populations and communities remain rare. We hypothesized that spatially heterogeneous disturbances of moderate intensity would promote metacommunity stability by decreasing the spatial synchrony of species fluctuations. To test this hypothesis, we exposed rocky shore communities of algae and invertebrates to homogeneous and gradient-like spatial patterns of disturbance at two levels of intensity for 4 years and used synchrony networks to characterize community responses to these disturbances. The gradient-like disturbance at low intensity enhanced spatial β diversity compared to the other treatments and produced the most heterogeneous and least synchronized network, which was also the most stable in terms of population and community fluctuations. In contrast, homogeneous disturbance destabilized the community, enhancing spatial synchronization. Intense disturbances always reduced spatial β diversity, indicating that strong perturbations could destabilize communities via biotic homogenization regardless of their spatial structure. Our findings corroborated theoretical predictions, emphasizing the importance of spatially heterogeneous disturbances in promoting stability by amplifying asynchronous spatial and temporal fluctuations in population and community abundance. In contrast to other networks, synchrony networks are vulnerable to the removal of most peripheral nodes, which are less synchronized, but may contribute more to stability than other nodes by dampening large fluctuations in species abundance. Our findings suggest that climate change and direct anthropogenic disturbance can compromise the stability of ecological communities through combined effects on diversity and synchrony, as well as further affecting ecosystems through habitat loss.

A facultative mutualism between habitat-forming species enhances the resistance of rocky shore communities to heat waves

Heat waves have increased in frequency, duration, and magnitude in recent decades, causing mass mortality events in terrestrial and aquatic ecosystems. Arguably, mass mortalities of habitat-forming organisms – i.e., dominant sessile organisms that define habitats via their own physical structure – would be amongst the most dramatic impact of heat waves because of their negative, cascading consequences on their associated biodiversity. However, the resistance of habitat-forming organisms to heat waves can be enhanced if they associate with secondary habitat formers able to tolerate and modulate extreme heat levels. Here we show that a seaweed of the Porphyra/Pyropia (P/P) clade can shield primary habitat-forming mussels, Brachidontes rodriguezii, from the impacts of extreme temperatures in a southwestern Atlantic rocky intertidal shore. By means of P/P removal experiments and surveys, we illustrate that P/P cover (a) buffers temperatures in the understory mussel beds during daytime air exposure periods in the summer, (b) reduces mussel mortality and leads to increased mussel body condition during warm summer periods, and (c) can prevent mass mortality of mussels during the course of a heat wave. Additionally, by means of a mussel removal experiment we illustrate that mussel cover is critical for P/P establishment, which is in consonance with the remarkably higher P/P densities and cover observed in mussel beds relative to exposed rock surfaces across a ~70 km coastal range. Collectively, these findings reveal a facultative mutualism where mussels provide a favorable substrate for P/P colonization and P/P attenuates heat mediated mortality on mussels. The ability of P/P to enhance the resistance of mussel beds to extreme heat events and the occurrence of similar P/P-mussel associations during spring-summer at globally dispersed sites suggests a widespread importance of P/P for the stability of mussel beds and their associated communities under warming climates.

Diel activity patterns of rocky shore macroinvertebrates in the northern Baltic Sea

Marine invertebrates on rocky shores form dynamic communities in time and space. Invertebrates constitute important links in the food chain and in biogeochemical cycles and are thus essential for functioning ecosystems. Species can be diurnal or nocturnal, and adaptions can be explained by predation pressure and resource availability. Contrary to terrestrial species, marine invertebrates are less specialised in single hosts and can, when needed, switch habitats, a trait that favours survival, growth, and reproduction.Variation in movement patterns of macroinvertebrates was studied on the northwestern Åland Islands (Åland Sea) to assess changes in activity on a diel timescale along the summer season. Two methods were used to collect representative samples of both swimming and non-swimming species. The pool of macroinvertebrate taxa in the study area was controlled for by sampling ambient macroalgae-associated fauna. Results show that all swimming and epifaunal mobile macroinvertebrate taxa move actively either in the free water body or along the sea floor within a 24-h period. A preference towards nocturnal activity could be observed as the total abundance of macroinvertebrates was higher during the night. Mean taxonomic richness was somewhat higher at night for the swimming macroinvertebrates. The community structure of mobile macroinvertebrates changed within a 24-h period as, e.g. Palaemon spp. and P. ulvae were more prevalent, and larger individuals were generally more active at night. The methods used were suitable for describing the activity patterns of macroinvertebrates on shallow rocky shores, and the results are essential for understanding the temporal dynamics of complex littoral rocky shore communities.

Making Way for Ships: Displacement, Religion and Urban Space-Making in India’s Southwest Littoral

This article foregrounds the interlinkages between the urban space-making of Kochi, religion and the displacement of shore communities in the decades after the Independence of India in 1947. I analyse the happenings and narratives around post-Independent India’s development initiatives as a site to understand space, land and sea as crucial resources in relation to the development of the city and the displacement of the shore communities. Specifically, I examine how the establishment of the Cochin Shipyard, a public-sector company which builds and repairs ships, is entangled with displacement and religion in the development history of Kochi, a comparatively small port city on the south-western coast of the Indian subcontinent. I also trace the refiguring of the displaced people’s land as the place of ‘revengeful ghosts’ in vernacular literature, which, I argue, shows anxieties about the unjust treatment of the evicted communities. I use a diverse range of sources including newspaper reports, biographical notes, ethnographic accounts, myths and literature to recreate this forgotten chapter in the development of Kochi.

Building Back Better: Transportation Recovery Challenges From the 2018 Kaua`i Flooding Disaster

This study describes and analyzes the recovery of transportation systems damaged by flooding and landslides in 2018 on the island of Kaua’i, Hawai’i. Following describing the record-setting rainfall and massive landslides that closed the major highway connecting the North Shore communities with the rest of the island, the challenges of “building back better” are investigated. While there was an urgency to finish the roadway repairs as quickly as possible, there was also a need to reduce future risks from flooding and landslides. Strong leadership, coordination, communications, and resource sharing helped improve pre-existing traffic, congestion, parking, and accessibility concerns for residents and tourists. There are important lessons learned concerning the need for timely, accurate data and information. Mitigation and adaptation projects that go beyond simply replacing and repairing assets before the storm are also analyzed. Opportunities to utilize greener, nature-based, and context-sensitive design, engineering, and planning solutions to mitigate and adapt highways to climate-induced extreme events remain challenging even in a community known for scenic beauty, pristine natural areas, and rich cultural heritage. While the community-led efforts to implement improvements to the State park at the end of the road were exemplary, there are still ongoing challenges of increased climate threats and inflexible, limited systems for funding—not just in disaster recovery but also investments in community resilience.

Evidence for Carbonate System Mediated Shape Shift in an Intertidal Predatory Gastropod

Phenotypic plasticity represents an important first-line organism response to newly introduced or changing environmental constraints. Knowledge about structural responses to environmental stressors could thus be an essential measure to predict species and ecosystem responses to a world in change. In this study, we combined morphometric analyses with environmental modelling to identify direct shape responses of the predatory gastropod Nucella lapillus to large-scale variability in sea surface temperature and the carbonate system. Our models suggest that the state of the carbonate system and, more specifically, the substrate inhibitor ratio ([HCO3−][H+]−1) (SIR) has a dominant effect on the shell shape of this intertidal muricid. Populations in regions with a lower SIR tend to form narrower shells with a higher spire to body whorl ratio, whereas populations in areas with a higher SIR form wider shells with a much lower spire to body whorl ratio. These results indicate that a widespread phenotypic response of N. lapillus to continuing ocean acidification can be expected, potentially altering the phenotypic response pattern to predator or wave exposure regimes with profound implications for North Atlantic rocky shore communities.

Independent Effects of Species Removal and Asynchrony on Invariability of an Intertidal Rocky Shore Community

Ecological stability depends on interactions between different levels of biological organization. The insurance effects occur when increasing species diversity leads to more temporally invariable (i.e., more stable) community-level properties, due in part to asynchronous population-level fluctuations. While the study of insurance effects has received considerable attention, the role of dominant species that contribute with particular functional traits across different level of organizations is less understood. Using a field-based manipulative experiment, we investigated how species richness and different types of parameters at the population level, such as the invariability of dominants, population invariability, and population asynchrony, influence the community invariability. The experiment involved the repetitive removal of the canopy forming algaMazzaella laminarioides(hereafter “Mazzaella”) during 32 months in two rocky intertidal sites of northern-central Chile. We predicted that the invariability of dominants enhances community invariability, that the effect of multispecies population-level parameters on community invariability are dependent on species richness, and that subdominant algae are unable to fully compensate the loss of canopies of the dominant species. Biomass of algae and mobile invertebrates was quantified over time. We observed independent effects ofMazzaellaremoval and community-wide asynchrony on community invariability. While canopy removal reduced community invariability, population asynchrony boosted community invariability regardless of the presence of canopies. In addition, filamentous and foliose algae were unable to compensate the loss of biomass triggered by the experimental removal ofMazzaella. Canopy removal led to a severe decrement in the biomass of macrograzers, while, at the same time, increased the biomass of mesograzers. Asynchrony stemmed from compensatory trophic responses of mesograzers to increased abundances of opportunistic algae. Thus, further work on consumer-resource interactions will improve our understanding of the links between population- and community-level aspects of stability.

Anthropogenic pressures enhance the deleterious effects of extreme storms on rocky shore communities

Climate change is not only changing the mean values of environmental parameters that modulate ecosystems, but also the regime of disturbances. Among them, extreme events have a key role in structuring biological communities. Ecosystems are frequently suffering multiple anthropogenic pressures which can cause effects that are not additive. Thus, the effects of extreme events need to be studied in combination with other pressures to adequately evaluate their consequences. We performed a manipulative approach in two rocky shores in the Mediterranean with contrasting levels of anthropogenic pressure (mainly eutrophication) simulating storms with different disturbance regimes in the intertidal and subtidal zones. In the short-term, an extreme storm had a greater impact on the species assemblage than other disturbance regimes, being especially notable in the area suffering from a high anthropogenic pressure. In this area, the species assemblages that suffered from an extreme storm took a longer time to recover than the ones affected by other disturbance regimes and were generally more affected after the disturbance. The intertidal zone, having more variable environmental conditions than the subtidal zone, was more resistant and able to recover from extreme storms. Our results suggest that the effects of extreme events on biological communities could be strengthened when co-occurring with anthropogenic pressures, especially ecosystems adapted to less variable environmental conditions. Thus, limiting other anthropogenic pressures that ecosystems are suffering is crucial to maintain the natural resistance and recovery capacity of ecosystems towards extreme events such as storms.

Temperature-buffering by oyster habitat provides temporal stability for rocky shore communities

Intertidal rocky shores are considered among the most thermally stressful marine ecosystems, where many species live close to their upper thermal limit and depend on access to cool microclimates to persist through heat events. In such environments, the provision of cool microclimates by habitat-forming species enables persistence of associated species during high temperature events. We assessed whether, by maintaining cool microclimates through heat events, habitat formed by rock oysters (Saccostrea cucullata) provides temporal stability to associated invertebrate communities over periods of extreme temperatures. On three tropical rocky shores of Hong Kong, which experiences a monsoonal climate, we compared changes in microclimates and invertebrate communities associated with oyster and bare rock habitats between the cool and hot seasons. Oyster habitats were, across both seasons, consistently characterised by lower maximum temperatures and greater thermal stability than bare rock habitats. Invertebrate communities in the bare rock habitat were less diverse and abundant in the hot than the cool season, but communities in the cooler habitats provided by oysters did not display temporal change. These results demonstrate that microclimates formed by oysters provide temporal stability to associated communities across periods of temperature change and are key determinants of species distributions in thermally stressful environments. The conservation and restoration of oyster habitats may, therefore, build resilience in associated ecological communities subject to ongoing environmental change.

Biogeographic drivers of distribution and abundance in an alien ecosystem engineer: Transboundary range expansion, barriers to spread, and spatial structure

AbstractAimBiogeographic boundaries can act as either weak or strong barriers to the spread of species undergoing distributional change. Once a novel species spreads across a boundary, it can have a substantial impact on the ecosystem, for instance by competing with local species, and, over the long‐term, re‐engineer the ecosystem. Marine biogeographic regions are clearly defined on the coast of southern Africa and we tested the influence of their boundaries on the spread and spatial structure of an alien ecosystem engineer.LocationSouthern Africa.TaxonAn invasive mussel, Mytilus galloprovincialis.MethodsRecords of M. galloprovincialis were compiled into a database to determine its decadal patterns of spread across multiple bioregions. Distribution and abundance (estimated using density and semi‐quantitative abundance scale [ACFOR]) of this mussel were surveyed to determine patterns in spatial structure across bioregions. In addition, we compared the size structure of populations at the eastern margins of its range with those of larger populations nearer the range centre.ResultsInitial breaching of biogeographic boundaries was associated with rapid spread, but other boundaries encountered decades later acted as barriers to further spread. Across >2,800 km of coast, spatial autocorrelation was observed in densities (low and mid shore levels) and in ACFOR abundances. Repeating spatial patterns in densities and ACFOR abundance were detected at scales of 120–160 km and of 400–990 km. Considerable effort was required to detect populations at the absolute eastern limits of its distribution.Main conclusionDetection of spatial structures at multiple scales suggests that ecologically determined processes regulate abundance at both intra‐bioregional and inter‐bioregional scales, which may help tease apart the historic and contemporary consequences of interspecific interactions on the structure of rocky shore communities. This study demonstrates the influence of biogeography in driving temporal patterns of spread and spatial structure on the distribution and abundance of an invasive species.

The Use of Cultural Competency in Decreasing Diabetes Outcomes Disparities in a Community Health Care Setting

In the United States, the prevalence of diabetes in the Latnix population is roughly 70% higher than in non-Latinx whites. Along with this, many studies have shown that the rate of complications, both macro- and microvascular, in this population is also disproportionately higher. Given that complication rates mirror glycemic control, as evidenced by studies such as the DCCT and UKPDS, the increased rate of poor glycemic control is likely one of the most important factors contributing to this. Most efforts at controlling diabetes in a population have aimed at a heterogeneous cohort in terms of race and ethnicity, yet poor control disproportionately affects the Latinx groups. North Shore Community Health Center is a Federally Qualified Health Center located around the communities of Salem, Peabody, and Gloucester, MA. These areas are ethnically diverse, and the vast majority of the Latinx population are Dominican. In fact, roughly 50% of the clinic population is Latinx. After prioritizing glycemic control as a goal for 2019, we utilized a population health strategy to identify patients with A1c >9% (poor control as defined by UDS measurements). These patients were given an appointment with the only endocrinologist in the clinic, who, through a Dominican Spanish translator and using joint decision making, decided on appropriate medication. They were then followed at least weekly at first by a nurse who also was Dominican and lived in the community. She counseled patients on culturally-appropriate diet recommendations, activity, screening, monitoring, and provided access to other specialties (e.g. podiatry, ophthalmology) as needed. The rate of A1c >9% in the clinic had been 35–40% prior 2019. At the end of 2019, the rate was 27%, with a disproportionaltly lower rate in the Latinx population (23%). Our conclusion is that a culturally sensitive diabetes program will eliminate these health disparities

Discursive practices of territorial stigmatization: how newspapers frame violence and crime in a Chicago community

ABSTRACT This article deciphers the discursive practices through which Chicago’s two major newspapers, the Chicago Tribune and the Chicago Sun-Times, stigmatize the South Shore community on Chicago’s South Side. Through a Critical Discourse Analysis (CDA), this article provides an in-depth linguistic analysis of the causation of territorial stigmatization through press coverage. It demonstrates that the two newspapers not only stigmatize South Shore through practices of hyperbolic naming, but that territorial stigmatization also flows from the transitivity of newspaper articles itself. By focusing on the transitivity of newspaper articles and their role in the production of territorial stigma, this article broadens our understanding of how territorial stigma is produced through symbolic defamation and denigration of spaces. It is argued that the two newspapers normalize and naturalize violence and crime as commonsense characteristics of everyday life in South Shore, thereby producing an image of South Shore as a space determined and indelibly shaped by violence and crime.

Ecology and genetics of Mytilus galloprovincialis: A threat to bivalve aquaculture in southern Brazil

The commercial mussel Mytilus galloprovincialis is invasive in the Southern Hemisphere having a large impact on rocky shore communities. It recently appeared in the state of Santa Catarina (SC) which is the most important shellfish aquacultural region in Brazil. Whether this introduction was intentional or accidental is unclear. We used single nucleotide polymorphisms (SNPs) to study population genetics of four introduced populations within at most 70 km from one another in SC; strong similarity among these populations suggests a single introduction event. The Mediterranean Sea is the most probable origin. We monitored recruitment of the invasive Mytilus in the site most affected by the invasion and compare it with Perna perna, the local commercial species. Results reveal that both species have similar seasonal recruitment trends along the year, which makes it impossible to control the invasive species by recruitment management. We recommended the suppression of Perna perna production in the most affected site for at least one year, beginning prior to the reproductive season, followed by cleaning all mussel fouling on submerged and floating structures. This study provides baseline data of an invasive process at its beginning and adds ecological and genetic information for one of the 100 most invasive species worldwide. This information, and continued study will help us understand the evolutionary process of invasion, and the rate of and degree to which M. galloprovincialis adapts to a new, warm environment in the southern hemisphere.

Habitat-Diversity Relations between Sessile Macrobenthos and Benthic Copepods in the Rocky Shores of a Marine Protected Area

In rocky shore systems, sessile macrobenthic assemblages may act as “ecosystem engineers” for many smaller benthic organisms. Thus, the influence of macrobenthic coverage on the diversity and assemblage structure of the harpacticoid copepod fauna was investigated in the rocky shores of a Marine Protect Area (MPA) in the Ligurian Sea (NW, Mediterranean Sea). Two sampling sites were investigated in two seasons at three different depths on both sub-vertical and inclined reefs. A total of 61 species of copepods mainly represented by Miraciidae, Laophontidae, Longipediidae and Thalestridae were found. The complex micro-topography of these substrata provided a wide variety of niches for many species with different lifestyles that suggests the important role of rocky shores to ensure the functioning of coastal ecosystems. The harpacticoid assemblage structure seemed mainly influenced by season and depth. The temporal spread observed is likely one of the underlying mechanisms of niche segregation that allows many species to co-occur in this specific environment along with a subordinate spatial segregation corresponding to the depth gradient. The results seem to support the hypothesis that the different species composition of the “ecosystem engineer” (and consequently its structure changes) are relevant in structuring the copepod assemblages. The comparison with previous data on general meiofauna underlines that higher surrogacy of the taxonomic identification could be used to study rocky shore communities, but the rich diversity that these systems host can only be understood at the lower taxonomic levels. The same holds for future evaluations of impact of environmental changes (including MPA regulations) on meiofaunal assemblages.