Search

Dictyostelid cellular slime molds are a ubiquitous component of most soils, where they feed upon bacteria and other microbes and thus play an essential role in the soil ecosystem. Herein we review the available literature on dictyostelid cellular slime molds in China, especially their diversity and ecology. The patterns of distribution for these organisms in relation to the different habitats with which they are associated are analyzed and discussed. In addition, the assemblages of dictyostelids reported from China and the United States were compared. The CC value obtained (0.48) indicates that China and the United States are perhaps less similar than might be expected. Our data point out the need for further studies to characterize more completely the assemblages of dictyostelids associated with particular vegetation types or particular regions throughout the world. • The diversity and ecology of dictyostelids in China were analyzed. • The assemblages of dictyostelds reported from China and the United States are compared and discussed. [ABSTRACT FROM AUTHOR]

Earthworms contribute to a wide range of ecosystem services provided by the soil. Nevertheless, synecology of these organisms is still not properly elucidated especially in terms of species interactions. The aim of the present study was to determine the effects of anecic earthworm species interactions on their individual biomass. These effects were measured using three epi-anecic species, Lumbricus rubellus rubellus (Hoffmeister, 1843), Lumbricus centralis (Bouché, 1972), Lumbricus terrestris (Linné 1758), and three strict-anecic species, Aporrectodea caliginosa meridionalis (Bouché, 1972), Aporrectodea nocturna (Evans, 1946), Aporrectodea giardi (Savigny, 1826). Twenty-one pairs of individuals were established following five assemblages: monospecific pairwise assemblages of epi- and strict-anecic earthworms (2 × 3 treatments), bispecific pairwise assemblages within epi- and within strict-anecic earthworms (2 × 3 treatments) and bispecific pairwise assemblages with one epi- and one strict-anecic earthworm (3 × 3 treatments). Treatments were maintained in mesocosms for 30 days under controlled conditions (food provided at the soil surface at the beginning of the experiment) and changes in the earthworm individual biomass were measured. Strict-anecic earthworms in monospecific or bispecific assemblages maintained their initial biomass. In contrast, epi-anecic earthworms exhibited an increase of 12.4% and 23.7% of their biomass in monospecific and bispecific assemblages, respectively. In bispecific assemblages combining one epi- and one strict-anecic earthworm, epi-anecic earthworms solely gained biomass leading to a total increase of a 6.9%. Surprisingly, the biomass' changes were not homogenous within the two sub-categories as the six earthworm species exhibited species-specific responses. The greatest increases in individual biomass were recorded for epi-anecic earthworms in the bispecific assemblages. This study provides further evidence for the distinction between the two anecic sub-categories, as it indicates that species interactions is positive only for epi-anecic earthworm biomass. • Effects of anecic earthworm interactions on individual biomass were investigated. • Epi-anecic earthworms gained biomass in mono (12%) and bi-specific (24%) assemblages. • Strict-anecic earthworms maintained their initial biomass. • Epi-anecic earthworm species interactions enhanced their gain of biomass. [ABSTRACT FROM AUTHOR]

Abstract Host species has an important influence on the distribution of epiphytic lichens in forests. However, the importance of non-dominant trees in shaping lichen communities has been poorly studied owing to the relative rarity of individuals. The importance of dominant and non-dominant trees for distribution of epiphytic lichens was determined in eight subtropical forests in southwestern China. Dominant trees supported more abundant total and exclusive lichen species only in secondary forests. The occurrence of non-dominant trees promoted lichen diversity within forest types and influenced lichen communities on both tree groups. The effects of total tree species on lichen distribution largely resulted from the presence of non-dominant trees. Dominant and non-dominant trees supported distinct lichen assemblages within forest types, and ordination analyses showed a clear separation. Our study, therefore, reinforces the importance of non-dominant trees for conserving epiphytic lichens, and highlights that lichen assemblages are shaped by both dominant and non-dominant trees. Highlights • The importance of dominant and non-dominant trees on epiphytic lichens was studied. • Dominant and non-dominant trees supported distinct lichen assemblages within stands. • The occurrence of non-dominant trees enhanced epiphytic lichen diversity. • Dominant trees were not always more important for lichen species. [ABSTRACT FROM AUTHOR]

In December 2007, approximately 10,900 tons of oil from a crude carrier spread rapidly onto the coast of South Korea. We studied the effects of oil on meiofauna by comparing two contaminated intertidal sites with an uncontaminated site. During 2008–2009, the density of meiofauna fluctuated among the contaminated sites but did not vary by season. Seasonal changes in density were observed at contaminated sites 3 years after the oil accident. Meiofauna appeared to be more sensitive to oil pollution stress at the more heavily contaminated site than at the less contaminated site. CLUSTER analysis showed that meiofauna communities in the 3 years immediately following the accident significantly differed from those sampled later. A non-metric multidimensional scaling analysis showed that nematode species composition in the first month after the accident significantly differed from those sampled later. Long-term monitoring is needed to assess the effects of oil on the meiofaunal community. [ABSTRACT FROM AUTHOR]

In alpine environments facilitator species buffer environmental extremes while building up soil resources above that of open areas. These modulating effects are critical for the persistence of species out of their optimal range and contribute to increase community-level plant species richness and phylogenetic diversity. We analyzed the effects of seven potential facilitator species with contrasting morphologies on subordinate plant species along a crossed environmental gradient, linking such effects to canopy effects. We also used these patches consisting of multiple shrub species to evaluate the effects of the whole shrub community on species richness and phylogenetic diversity, and whether such shrub community effects differed along the gradient. We used ecological and phylogenetic data of alpine plant communities along two altitudinal gradients on opposing aspects of the Sierra Nevada Mountains (Spain). As expected, shrubs buffered harsh abiotic conditions by decreasing mean temperatures and increasing relative humidity with regard to open areas. Composition of subordinate plant communities differed among shrubs and among sites, and correlated with relative humidity along the gradient pointing to the dependence of subordinate species on micro-environments created by shrubs. There were a variety of shrub effects on overall plant abundance and richness depending on shrub identity. In the most extreme sites we recorded generally positive effects of the shrub community, which promoted whole-community species richness and phylogenetic diversity despite species-specific effects ranging from clearly negative to positive. Our data therefore show that the effect of different shrub species on plant community richness and phylogenetic diversity is not redundant, as every shrub species may host unique communities, thereby affecting the structure and composition of the whole community. [ABSTRACT FROM AUTHOR]

The multidisciplinary IDEADOS project funded by the Spanish Government was developed between 2009 and 2012 aiming to determine the relationships between environmental conditions and the nekto-benthic slope communities in two areas of the western Mediterranean, north and south of the Balearic Islands, with different geomorphologic and hydrodynamic characteristics. In this paper we describe the background and goals of this project, its study area and the sampling strategy applied, as well as the main conclusions reached in a final workshop. This volume is a compendium of the main contributions presented at this workshop, which have been peer-reviewed and can represent the state of the art of the complex interactions between the pelagic domain and the slope benthic communities, within the context of the hydrodynamics and oligotrophy of the Balearic Islands, and considering different temporal scales and organization levels. [ABSTRACT FROM AUTHOR]

The diel vertical distribution of fish larvae off the Balearic Islands during late autumn and summer was analysed in relation to the environmental conditions. Four fixed sampling stations, located in the outer shelf and slope zones, were sampled during both the day and night by means of oblique hauls at different water depths. In autumn the first 60 m were characterised by vertical mixing and relatively higher fluorescence values, while summer was characterised by strong near-surface stratification and the presence of a Deep Fluorescence Maximum (DFM). The fish larval community was dominated by mesopelagic species, myctophiforms and stomiiforms, with some differences in species composition and their relative contribution between periods. A higher number of species was observed to reproduce in summer. The diel vertical distribution patterns differed among species and, within species, some differences were detected between the day and night. Although their relative depth preferences were similar between surveys, seasonal comparisons for the most abundant species showed that in autumn larvae presented both a shallower distribution during the day and a deeper distribution during the night than in the summer period. The larvae of all species, except for Argyropelecus hemigymnus , were absent from layers below 200 m. In these deeper layers, only A . hemigymnus larvae and juvenile stages of myctophiforms and stomiiforms were found. Another group of species, including Hygophum benoiti, Ceratoscopelus maderensis, Cyclothone braueri and Lampanyctus crocodilus , characterised the surface assemblage, mainly appearing in the first 50 m during the day, while at night their distribution was wider, extending to deeper layers. Benthosema glaciale , Symbolophorus veranyi and Myctophum punctatum were located at intermediate levels (mostly 50–100 m). Larval size stratification was evident for the most abundant species, with younger stages being found at shallower depths in the water column, while postflexion stages presented a wide distribution at night, undergoing vertical displacement to the near-surface layers during the day. The roles of the position of the thermocline, the availability of food and light intensity as factors modulating these differences are discussed. [ABSTRACT FROM AUTHOR]

Although much work has been done on factors which influence the patterning of species and species trait assemblages in a variety of groups such as plants, vertebrates and invertebrates, few studies have been realized at a broad geographic scale. We analyzed patterns of relationships between species, species trait distribution/assembly, and environmental variables from the west of Europe to Slovakia, Poland and Sweden. We created a database by compiling traits and occurrence data of European collembolan species, using literature and personal field studies embracing a large range of environmental gradients (vertical stratification, habitat closure, humus form, soil acidity and moisture, temperature, rainfall, altitude) over which Collembola are supposed to be distributed. Occurrences of the 58 best-documented species, environmental variables and species traits allowed us to (i) show which environmental variables impact the distribution of the 58 species at broad scale and (ii) document to what extent environmental variables and species trait assemblages are related and which trends could be found in trait/environment relationships. The impact of vertical stratification, habitat closure, humus form, soil acidity, soil moisture, temperature, and to a lesser extent rainfall and altitude on species distribution, firstly revealed by indirect gradient analysis (correspondence analysis, CA), was further shown to be significant by direct gradient analysis (canonical correspondence analysis, CCA). RLQ analyses were performed to find linear combination of variables of table R (environmental variables) and linear combinations of the variables of table Q (species traits) of maximum covariance weighted by species occurrence data contained in table L. RLQ followed by permutation tests showed that all tested environmental variables apparently contributed significantly to the assemblages of the twelve species traits studied. A convergence was observed between traits related to vertical stratification and those related to habitat closure/aperture. Well-developed locomotory organs (furcula, legs), presence of sensorial organs sensitive to air movements and light (e.g. trichobothria and eye spots), spherical body, large body size, pigmentation (UV protection and signaling) and sexual reproduction largely occur in epigeic and open habitats, while most of woodland and edaphic habitats are characterized by short locomotory appendages, small body size, high number of defense organs (pseudocelli), presence of post-antennal organs and parthenogenesis. Climate and especially temperature exert an effect on the assemblage of traits that are mostly present above-ground and in open habitats. The contribution of combinations of some environmental variables to the occurrence of each species trait was tested by linear, logistic or multinomial regression (Generalized Linear Models). Vertical stratification, followed by temperature, played a dominant role in the variation of the twelve studied traits. Relationships between traits and environment tested here shows that it is possible to use some traits as proxies to identify potential ecological preferences or tolerances of invertebrate species. However, a significant part of species distribution remained unexplained, probably partly because some traits, like ecophysiological ones, or traits involved in biotic interactions (e.g. competition) were unavailable. The present work is thus a first step towards the creation of models predicting changes in collembolan communities. Further studies are required to inform ecophysiological traits, in order to complete such models. Moreover the niche width of species will have to be determined. [ABSTRACT FROM AUTHOR]

Highlights: [•] We studied beetles and plants in forest of a native vs. introduced tree in Sweden. [•] We compared the introduced lodgepole pine with the native Scots pine. [•] Epigaeic beetle abundance was much lower under lodgepole pine than Scots pine. [•] Assemblage structure in beetles and vegetation differed between the two pines. [•] Using introduced tree species in boreal forestry may affect understory biodiversity. [ABSTRACT FROM AUTHOR]

Abstract: The mesopelagic fish community of the western Mediterranean was studied during two cruises carried out in December 2009 and July 2010 in the shelf and slope zones around the Balearic Islands. Much of what was previously known about this deep water group of fishes in the Mediterranean Sea came from studies performed using planktonic and small midwater nets. This study was the first attempt to use large pelagic trawls and small nets combined with information about the main sound scattering layers to analyse mesopelagic fish composition, diversity and species assemblages. This community is characterised by a relatively low diversity compared to other oceanic regions of the world, with Myctophiformes and Stomiiformes being the main contributors. Bathymetry and the level of the water column were the most important factors structuring the investigated fish assemblages, and similar vertical patterns were observed for the different species collected during the two study periods. A shelf assemblage composed of a few species of myctophids, with Notoscopelus elongatus being the main contributor, was distinguished. The slope assemblage included both Myctophiformes and Stomiiformes that showed differences in their day–night main location along the water column. In terms of species behaviour, two important groups were detected. The first was non-migrant or weakly migrant species, with the paradigmatic example being the gonostomatid Cyclothone braueri, which occurred at a depth of 400–600m; this species is partly responsible for the permanent acoustic (38kHz) response at this depth. The second group, near-surface migrants at night, was represented by most of the juvenile and adult myctophids, exemplified by Ceratoscopelus maderensis, with the exception of just a few of the largest size classes of some species, such as Lampanyctus crocodilus and N. elongatus that remain near the bottom. [Copyright &y& Elsevier]

• Small mammals' taxonomic and functional composition vary with landscape pattern. • Species assemblages tend to be simpler in anthropogenic landscapes. • Seminatural and anthropogenic landscapes influence functional composition. • Understanding community assembly could help prioritise conservation actions. Mediterranean landscapes constitute a biodiversity hotspot where species distribution and composition have been shaped by a long history of traditional land use. In this work, we investigated the effects of landscape patterns on community composition and the functional, morphological, and ecological traits of 21 small mammal species in the Mediterranean region. We extracted species abundance and trait data from 86 georeferenced Common Barn-owl pellet sites collected in Central Italy, covering 33,000 km2, and stored in the OpenMICE database. Additionally, we measured 12 landscape metrics on land cover maps produced at intervals coeval with pellet collection dates. We explored the variation in species composition against landscape pattern metrics using canonical correspondence analysis (CCA). Moreover, we analysed the relationships among small mammals' occurrence, their life history traits, and landscape pattern metrics using the fourth-corner model approach. Our results highlighted the key role of landscape composition and configuration in shaping small mammal species composition and their functional traits. Species and trait composition varied along two main landscape gradients, with a simplification of species assemblage towards increasing human pressure (i.e., artificial surfaces and agricultural areas) and decreasing cover of seminatural areas. The observed variability of species assemblages and functional traits across Mediterranean landscape gradients highlights the need to preserve diverse ecosystems and land cover types to maintain small mammal biodiversity and related ecosystem functioning. [ABSTRACT FROM AUTHOR]

Abstract: A living organism is part of a perceived “spatial configuration” (i.e., an eco-field) when it changes the properties of the medium in which it lives. This happens because species evolve strategies to tackle ecological constraints; these strategies appear as species traits (physiology, morphology, behavior), and species traits affect environmental features. On the basis of species traits, data on carabid beetles from different habitats in two widely separated regions of Italy were analyzed in order to test the eco-field idea. The results revealed that the underlying environmental factors influencing the distribution of species traits over different habitats are anthropogenic disturbance, and stable vs. unstable stages of ecological succession. This approach, based on eco-field and species traits, has potential power in studies in which it is more important to emphasize ecological similarity than taxonomical heterogeneity. [Copyright &y& Elsevier]

Abstract: Riparian zones are complex disturbance-mediated systems that are highly susceptible to invasion by alien plants. They are prioritized in most alien-plant management initiatives in South Africa. The current practice for the restoration of cleared riparian areas relies largely on the unaided recovery of native species from residual individuals and regeneration from soil-stored seed banks. Little is known about the factors that determine the effectiveness of this approach. We need to know how seed banks of native species in riparian ecosystems are affected by invasion, and the potential for cleared riparian areas to recover unaided after clearing operations. Study sites were selected on four river systems in the Western Cape: the Berg, Eerste, Molenaars and Wit Rivers. Plots were selected in both invaded (>75% Invasive Alien Plant (IAP) canopy cover) and un-invaded (also termed reference, with <25% IAP canopy cover) sections of the rivers. Replicate plots were established at two elevations (mountain stream and foothill) and in three moisture regimes (dry, wet and transitional bank zones). Soil samples were taken, surveys were done of the aboveground vegetation, and comparisons were made between invaded and non-invaded sites. Seed bank communities were clearly defined by the state of the river (reference or invaded) and moisture regimes (wet and dry bank zones). Comparisons at a landscape scale showed no clear pattern, as the composition of both aboveground and seed bank species assemblages were strongly influenced by site history, especially the extent of invasion and fire frequency. Even after heavy and extensive invasion, riparian seed banks have the potential to initiate the restoration process. However, not all riparian species are represented in the seed bank. Based on these results, restoration recommendations are outlined for alien-invaded riparian zones. [Copyright &y& Elsevier]

Comparison of the two flagship species of British bumblebee conservation (Bombus distinguendus and B. sylvarum) with a widespread, common, and more stable species (B. pascuorum) shows (1) that the two rarer and range-declining species in Britain had narrower (more specialized) climatic niches in western Europe even before their most severe declines, and (2) that the areas where they persist in Britain from 2000 onwards are closer climatically to the centres of their pre-decline west-European climatic niches than the areas from which they have been lost. Although data are available for few bumblebee species at present and further tests are needed, the first result supports earlier suggestions that it is bumblebee species with narrower climatic niches that are most vulnerable to decline. The second result supports the suggestion that it is in areas nearer the edges of their climatic niches where these species are most vulnerable to decline, although this can be ameliorated locally by higher food-resource levels. This is not to say that all patterns of bumblebee decline have been influenced by climatic niche, particularly in North America. Nonetheless, in Britain we find that even without climatic change, an interaction between climatic niche and food-plant reductions from land-use change retains the potential to explain at least some of the broader patterns of which species have declined, where they have declined, and how they have declined. [Copyright &y& Elsevier]

Abstract: Our objective was to understand how marine birds respond to oceanographic variability across the Southern Indian Ocean using data collected during an 16-day cruise (4–21 January 2003). We quantified concurrent water mass distributions, ocean productivity patterns, and seabird distributions across a heterogeneous pelagic ecosystem from subtropical to sub-Antarctic waters. We surveyed 5155km and sighted 15,606 birds from 51 species, and used these data to investigate how seabirds respond to spatial variability in the structure and productivity of the ocean. We addressed two spatial scales: the structure of seabird communities across macro-mega scale (1000skm) biogeographic domains, and their coarse-scale (10skm) aggregation at hydrographic and bathymetric gradients. Both seabird density and species composition changed with latitudinal and onshore–offshore gradients in depth, water temperature, and chlorophyll-a concentration. The average seabird density increased across the subtropical convergence (STC) from 2.4 birdskm−2 in subtropical waters to 23.8 birdskm−2 in sub-Antarctic waters. The composition of the avifauna also differed across biogeographic domains. Prions (Pachyptila spp.) accounted for 57% of all sub-Antarctic birds, wedge-tailed shearwaters (Puffinus pacificus) accounted for 46% of all subtropical birds, and Indian Ocean yellow-nosed albatross (Thallasarche carteri) accounted for 32% of all birds in the STC. While surface feeders were the most abundant foraging guild across the study area, divers were disproportionately more numerous in the sub-Antarctic domain, and plungers were disproportionately more abundant in subtropical waters. Seabird densities were also higher within shallow shelf-slope regions, especially in sub-Antarctic waters, where large numbers of breeding seabirds concentrated. However, we did not find elevated seabird densities along the STC, suggesting that this broad frontal region is not a site of enhanced aggregation. [Copyright &y& Elsevier]

Copyright of Basic & Applied Ecology is the property of Urban & Fischer Verlag and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: The composition and richness of woody species were experimentally tested in assemblages that were put together in order to evaluate – 18 months later – the combination that impacts several variables of woody community development the most and thus, its value on cloud forest rehabilitation. The experiment was conducted in an area of eastern Mexico characterized by cloud forest that had been severely damaged by plant cover removal and erosion as well as soil mixing and compacting caused by heavy machinery. Ten, 1-year-old, native woody species were employed to construct the assemblages. All species used in the experiment are native to eastern Mexican cloud forest, and each was included in at least two assemblages. More than half of the individuals that made up each assemblage succeeded in establishing and growing despite the dire condition of the study area; this was also true for 8 of the 10 species that made up assemblages. No evidence was found to suggest that assemblages affect development or survival at plot level, nor did the richness and composition of assemblages seem important in terms of community organization. However, in five species, assemblages were noted to influence some of the developmental variables analyzed, as the best performance came from the richest assemblage. The relative success of all assemblages and most individual species shows that it is possible to accelerate secondary succession in cloud forest by establishing assemblages of woody species juveniles. The results suggest that in this forest rehabilitation, any assemblage can be employed. Given the effects on each species, it is advisable to include the ones which exhibit the best survival and response under altered conditions in terms of crown size and height (Quercus, Carpinus, and Ulmus). [Copyright &y& Elsevier]

Recent studies of British bumblebees have proposed a seemingly simple explanation for the decline in some species: that greater dietary specialization among the rarer species has put them at greater risk. However, comparisons of dietary specialization require: (1) that bees have access to the same dietary options among which to make their choices; (2) that the differing relative breadths of dietary choices made are not obscured by the differing sample sizes among bee species. Using one of the few suitable data sets, I find no evidence for a relationship between, on the one hand, rarity or declines in British bumblebees and, on the other, their dietary breadths, the strengths of their dietary preferences, or their proboscis lengths (which influence dietary choices). In contrast, there is support for a relationship between rarity or declines within Britain and the sizes of species’ European ranges, particularly when these measures are adjusted to represent their ranges near sea level. Adjusted range sizes may reflect overall niche breadth and perhaps climatic and habitat specialization. This is not to say that climate change is the driving factor for declines or that changing food-plant availability is unimportant, but that climatic and habitat specialization may be a better indicator of risk of decline, which deserves further study. [Copyright &y& Elsevier]

The faunal composition and species abundance indices, according to data collected during 1996–2000 within the framework of the Mediterranean International Trawling Survey Program (MEDITS) at 65 sampling sites in North Aegean Sea and its surrounding coastal basins, were used to determine fish species assemblages, their geographical distribution and temporal variation. A principal component analysis (PCA) was applied to detect fish species associations and 11 principal axes were extracted, accounting for the 67.1% of system’s variance. According to these fish assemblages, three main geographical areas were distinguished in the North Aegean Sea: the Thracian Sea, Thermaikos gulf and the southern part of the sampled area, between the coast of Asian Minor and the Eastern coast of the Greek peninsula. These areas could be used for future multi-species fishery management purposes, related to the particular environmental conditions prevailing in each unit. [Copyright &y& Elsevier]

Offshore Onna Village, Okinawa Island, Japan, there is a large and densely covered coral assemblage of free-living mushroom corals (Scleractinia: Fungiidae) on a reef slope at depths from 20 m to 32 m, covering an area of approximately 350 × 40 m2. From previous research, it is known that migration distances of mushroom corals may depend on coral shapes, coral sizes, substrate, and bottom inclination. However, until now there have been no published examples of regular Fungiidae movement and behavior from typhoon-exposed coastlines, such as those in the western Pacific Ocean. Our surveys across three years offshore Onna Village show that mushroom corals always move in down-slope direction from shallow to deeper reef zones. The results indicated that mushroom corals migrated faster in autumn than in other seasons, and that oval-elongate fungiids, and particularly those with a smooth underside, migrated more quickly than species with other shapes. Surprisingly, we observed a negative relationship between the presence of typhoons and migration rates. We also observed active migration by fungiid individuals to escape situations in which they were threatened to become overgrown by Acropora corals, or when they needed to escape from burial underneath coral debris. • Individual mushroom coral movements were monitored across three years offshore of Okinawa Island. • Free-living mushroom corals (Fungiidae) moved in a down-slope direction. • Mushroom corals migrated faster in autumn; oval-elongate shaped species moved faster than other ones. • Most species-specific shapes, as well as sizes, and most seasons had no significant effect on migration rates. • Observed active migration by mushroom corals appeared to avoid burial in rubble or overgrowth. [ABSTRACT FROM AUTHOR]

The bamboo coral Isidella elongata is a key structuring species on deep muddy bottoms, which has suffered severe consequences from bottom-fishing activities, as it often co-occurs with precious fishery resources such as red shrimps. A five-year series of data collected during a scientific trawl survey was used to localize the presence and to characterize the associated megafauna over a wide spatial scale in the Western and Central Mediterranean (Sardinia, South-Central Tyrrhenian, Western Ionian and Southern Adriatic). In addition, the overlap of I. elongata hotspots with nursery and spawning areas of three selected species (Aristaeomorpha foliacea, Aristeus antennatus and Galeus melastomus) was analysed. The sizes of the colonies were analysed in the South-Central Tyrrhenian and the Southern Adriatic. No significant variation over time was observed in the former, while in the latter, the colonies were bigger but showed a decreasing trend over time. • The distribution of Isidella elongata in the Central-Western Mediterranean was studied. • The species diversity associated with I. elongata gardens is significantly higher. • Species assemblages associated with I. elongata differ from unassociated ones. • Colonies in the Adriatic are bigger than in the Tyrrhenian but are diminishing. • Isidella presence overlaps with nursery and/or spawning areas of some species. [ABSTRACT FROM AUTHOR]

The present study deals with benthic community structures of mussel beds (Mytilus galloprovincialis) in the Sea of Marmara, including the Çanakkale and İstanbul Straits. The Sea of Marmara's mussel beds were mainly formed by small-sized mussel individuals (shell length <4 cm). Macrobenthic species associated with the mussels support high diversity in the region, comprising 184 species belonging to 11 taxonomic groups. The annelids (38% of total number of species) were the most diverse group and arthropods (48% of total number of individuals) the most abundant. Motile species numerically dominated mussel beds at stations, while epibiont fauna were relatively low in terms of number of species and abundance. Five different species assemblages were identified in the region, which appeared to be mainly influenced by some biotic (e.g. mussel biomass, alien species) and abiotic (e.g. salinity) factors. The assemblages were mainly characterized by having high abundances of three crustacean (Jassa marmorata , Hyale schmidti and Melita palmata) and one polychaete (Platynereis dumerilii) species. Seven alien species were found at stations, of which the small-sized anthozoon Diadumene cincta accounted for 86% of total number of individuals of alien species. • The Marmara Sea's mussel beds were mainly composed of small-sized mussels. • The mussel beds had a diverse associated fauna. • Different species assemblages occurred in the region. • The community structures were mainly affected by salinity and mussel biomass • Invasive alien species occurred in mussel beds. [ABSTRACT FROM AUTHOR]

• Macroplankton and micronekton communities of the Central Ligurian Sea were described. • Vertical distribution of twenty-three species is reported. • The dissolved oxygen and salinity affects the distribution of zooplankton community. Changes in the composition and biomass distribution of deep-living zooplankton over wide gradients of depth (0–1300 m) have been analyzed in the Central Ligurian Basin (Northwestern Mediterranean Sea), seeking the environmental variables responsible for these changes. Spring vertical distribution (early May 2013) and diel vertical migration (DVM) of some key species of macroplankton and micronekton communities were studied every 6 h during a 24 h cycle. The hauls, performed with the multiple opening/closing 230 µm BIONESS net system, made possible a detailed description of the vertical distribution of twenty-three species: one siphonophore, one pyrosomid, one salp, three pteropods, four amphipods, one mysid, eight euphausiids, two decapods, two fishes. Cluster analysis performed on major species of macroplankton and micronekton community assemblage mainly highlighted the presence of four well defined assemblages, based on the depth range in the water column: 0–60 m, 60–100 m, 100–600 m and from 600 to 1300 m. During daytime, vertical distributions of biomass exhibited similar profiles, with maxima in the 0–60 m layer. Highest abundances were recorded between 20–40 and 40–60 m depth, at midnight and in the morning. The highest values of both biodiversity and number of species were found in a deeper layer comprised between 400 and 600 m. Most of the species showed similar distributions throughout the sampled area, either with typical non-diel-migrating characters such as the euphausiid Stylocheiron longicorne and the fishes Cyclothone braueri and C. pygmaea , or with clear diel-migrant behaviour (e.g. the siphonophore Chelophyes appendiculata and the euphausiid Euphausia krohni). Some species (e.g. Vibilia armata, Phronima sedentaria, Scina crassicornis, Salpa fusiformis, Cavolinia inflexa, Gennadas elegans) exhibited a bimodal vertical distribution that could be attributed to different causes able to influence and modify their vertical migration. The lower values of chlorophyll a concentrations found in the present studyinthe month of May corresponds to the transition period from a mesotrophic system to a rather oligotrophic one. Temperature and chlorophyll were the variables that principally influenced the distinction between shallow (0–60 m) and deep communities. Below 60 m depth, the dissolved oxygen and salinity become the most important variables affecting the zooplankton community. [ABSTRACT FROM AUTHOR]

The overexploitation of marine resources has led to a decrease in species abundance over time in many marine ecosystems worldwide. But as new fishers arise throughout the years, the perception of local abundance changes which might result in a "shifting baselines syndrome". We investigated how the perception of fishers about species abundance changed through time (from 1970 to 2016) and space (five ports), through questionnaires in the small-scale/artisanal fisheries of Murcia, Spain. Two major results emerged, firstly species catches significantly decreased between the decades 1970–1990 and 2000–2016, possibly due to overfishing and habitat degradation. Catches of species with some particular functional traits decreased (96%) possibly due to lower plasticity or to a "fishing down the food web" effect. Secondly, some functional trait categories (very large size, deep water depth, large yearly displacements and very vagile) were the highest in the northern ports of San Pedro del Pinatar and Cartagena while Cabo de Palos had the highest values in species with solitary and territorial behaviour and vagile or sedentary mobility. Fishers' perception of catch trends of commercial species seemed aligned with other sources of information for this area and might be key information in the absence of more quantitative information. • Fishers identified a decrease in abundance through time (from 1970 to 2016) especially before and after 1990. • Over 80% of species reported by fishers decreased in abundance through time (from 1970 to 2016) in the study area. • Over 90% of functional groups reported by fishers decreased in abundance through time (from 1970 to 2016) in the study area. • Species with certain traits decreased more abruptly through time (from 1970 to 2016) in the study area. [ABSTRACT FROM AUTHOR]