Polychaete assemblages along a rocky shore on the South Adriatic coast (Mediterranean Sea): patterns of spatial distribution (original) (raw)
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The knowledge on the hard bottom polychaete assemblages in the Northern Adriatic Sea, a Mediterranean region strongly affected by environmental pressures, is scarce and outdated. The objective of this paper was to update the information on polychaete diversity and depict their patterns of natural spatial variation, in relation to changes in algal coverage at increasing depth. Hard bottom benthos was quantitatively sampled by scraping off the substrate from three stations at Sveti Ivan Island (North Adriatic) at three depths (1.5 m, 5 m and 25 m). Polychaete fauna comprised 107 taxa (the majority of them identified at species level) belonging to 22 families, with the family Syllidae ranking first in terms of number of species, followed by Sabellidae, Nereididae, Eunicidae and Serpulidae. Considering the number of polychaete species and their identity, the present data differed considerably from previous studies carried out in the area. Two alien species, Lepidonotus tenuisetosus, whi...
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In the different mesophotic bioconstructions recently found along the Southeastern Italian coast, polychaetes have been proved to show high species richness and diversity, hitherto never investigated. In the present study, the species composition and functional role of polychaete assemblages were analysed; the updated key to identification of the Mediterranean species of genus Eunice was presented and some taxonomic issues were also discussed. On the total of 70 species Serpulidae and Eunicida were the dominant polychaetes. Facing similar levels of α-diversity, the polychaete assemblages showed a high turnover of species along the north-south gradient, clearly according to the current circulation pattern, as well as to the different bioconstructors as biological determinants. Indeed, Serpulidae were dominant on the mesophotic bioconstructions primarily formed by the deep-sea oyster Neopycnodonte cochlear, while the Eunicida prevailed on the mesophotic bioconstructions mainly built b...
Deep Sea Research Part I: Oceanographic Research Papers, 2019
Knowledge of the diversity of deep-sea polychaetes in the Mediterranean Sea is still scarce and fragmentary, due to the absence of comprehensive taxonomic revisions of several families, with the majority of recent works relying on higher level taxonomy. In the present work samples were collected with a box-corer along the Sardinian Slope, a bathyal escarpment area located in the western Mediterranean Sea, at seven depth levels separated from each other by a 300 m interval, ranging from 600 to 2400 m. Samples were sifted with a 0.3 mm mesh, and polychaetes were identified at the lowest taxonomic level and characterised from the biogeographic and tropho-functional point of view. Ninety-seven taxa were recorded, 60 of which identified at the species level; eight taxa are likely to be undescribed species, possibly endemic to the Mediterranean Sea, whereas another seven are reported for the first time for the Mediterranean Sea. The majority of taxa shows an Atlantic-Mediterranean or strictly Mediterranean distribution, thus confirming the similarity between Atlantic and Mediterranean deep-sea assemblages, but also the unicity of the latter. Conversely, cosmopolitan taxa, usually considered common in deep-sea assemblages, represented a minor component. The trophic guild composition of the assemblage varied along the slope, with shallower assemblages (600-900 m) including a relatively high percentage of predators and microphagous omnivores, while deeper assemblages (1500-1800 m) showed a > 90% percentage of deposit-and filter-feeders, with the 1200 m assemblage characterised by intermediate features. This outcome suggests that in the presently investigated area, the environmental conditions of shallower samples allow the stable occurrence of at least two trophic levels, whereas deeper assemblages depend mainly on organic matter coming from shallower levels and from the water column. The examined polychaete assemblages are characterised by low density and a complete absence of dominance, with the evenness index J' ranging from 0.72 to 1; the wide ranges of the H' index (0.50-2.67) and of Hill's N1 (1.65-14.65) suggest a high variability at low spatial scale. If compared to Atlantic deep-sea polychaete assemblages the assemblage studied shows an almost tenfold lower organism abundance, but species diversity is only two-to four-fold lower, suggesting that biodiversity in Mediterranean deep-sea environments is possibly underestimated. Diversity of polychaete assemblages in the deep Mediterranean Sea is likely to be underestimated due to their low density, and adequate sampling strategies should be planned to have a better insight into the functioning and diversity of these communities.
Ecology and spatial distribution of selected polychaete species from the Italian continental shelf
Italian Journal of Zoology, 2011
Data from several research and monitoring projects carried out between 1999 and 2009, for a total of 26 study areas located along the Italian continental shelf (Mediterranean Sea), were extracted from ISPRA's data set, to revise and update the existing information on the ecology and spatial distribution of 20 selected soft-sediment polychaete species. The species were selected taking into account their spatial distribution and ecological role in the benthic assemblages and the existence of voucher specimens deposited in ISPRA's reference collection. Samplings were taken at 872 stations on soft sediments, at depths ranging from 1 to 155 m. Surface sediment composition data were available at each site. The number of specimens from the selected species was extracted at each site, and relative abundance (%)calculated. The spatial distribution of each species was investigated according to the biogeographical zones identified in the Italian Seas. The distribution of five species (Aponuphis bilineata, A. brementi, A. fauveli, Nothria conchylega, and Onuphis eremita) was updated. Several species that were previously considered to be characteristic of a specific biocenosis, sensu Pérès & Picard (1964), e.g. Diopatra neapolitana, Ditrupa arietina, Notria conchylega and Sternaspis scutata, were found to be distributed over a wider bathymetric and granulometric range of surface sediments. Indicator Species Analysis highlights that the distribution of 17 selected species depends on definite granulometric characteristics of the sediment. This new relevant information outlines the important contribution of environmental monitoring programmes to scientific knowledge.
Sardá, R., Serrano, L., Labrune, C., Gil, J., March, D., Amouroux, J.M., Taboada, S., Bonifácio, P. and Grémare, A. 2014. Shallow-water polychaete assemblages in the northwestern Mediterranean Sea and its possible use in the evaluation of good environmental state. Memoirs of Museum Victoria 71: 289-301.
Marine Ecology, 1993
Biological wnation in brackish habitats is usually related to lhe gradients of several factors. of which salinity is often taken as the most important . In oontrast. rc«nt pape rs, mainly on Mediterra nean lagoons. have emphasized the role of other factors such as water movement and trophic Slams. In this paper. lhe distribution of polychaetcs in the Orbctello lagoon (a poIyhypcrhaline pond on the northern Tyrrhenian coast) is oompared with the gradients of a number of environmental parameters. Polychaete distribution turned out to be under the control ofa variety of highly interrelated factors. lbe study of biotic zonation as a function of a single driving factor is thus overly simpli~tic even when dealing with '~imple' envil"Qnmen ts. as lagoons arc often defined. Several factors and their synergistie effects must always be taken into account.
Non-indigenous polychaetes along the coasts of Italy: a critical review
Mediterranean Marine Science, 2020
Non-indigenous species (NIS) represent one of the most relevant threats to biodiversity, ecosystem functioning and human activities, and their occurrence and spread have been the subject of numerous works and revisions. However, the information available is rather confused for several taxa, including polychaetes, which are characterised by having a high number of cryptogenic and questionable species. This work aims at providing a revised checklist of alien polychaetes occurring along the coasts of Italy, based on the examination of newly collected and deposited material and on the critical analysis of published and gray literature, and whenever possible on the re-examination of historical material. Of the 86 polychaete species reported as NIS in Italian waters, 25 are confirmed as alien species, while 3 are cryptogenic, and 40 should be considered questionable. Finally, 18 species were excluded from non-indigenous species checklists, either because they are native, or because they r...
Zoosymposia
The artificial reef of Fregene, Italy, was built in 1981 as a multipurpose structure with the intent of protecting the coastal environment from illegal trawling and also improving fishery production. It is located at 10–14 m depth on a sandy-silty seabed in the Tyrrhenian Sea, 5 nmi north of the outlet of the Tevere River (Latium, Italy) and 1.5 nmi offshore the town of Fregene (Latium, Italy). The development of the polychaete community on the reef was studied from May 1981 to December 2001 in order to examine long-term community dynamics and verify to what extent changes in polychaete assemblage could depict the development of the benthic assemblage. At each sampling time, two standard surfaces of 400 cm2 were scraped from the vertical walls of the same block. Temporal changes in the development of the polychaete community were detected by univariate (S, N, ExpH', 1/Simpson, J') and multivariate (CLUSTER, nMDS) analysis of the faunal data. Functional structure of the comm...