Erica Keppel

Biodiversity and distribution of polychaetes and molluscs along the Dese estuary (Lagoon of Venice, Italy)

Mollusc and polychaete distribution in the mud flats along the Dese estuary (lagoon of Venice, Italy) was analysed in May, August and October to evaluate taxonomic biodiversity and zonation pattern of soft macrobenthos in an area of the lagoon hardly known from this point of view. Throughout the studied area most of the species were polychaetes, particularly Streblospio shrubsolii (Buchanan), which showed greater abundance from May to October. Molluscs and polychaetes showed a zonation of marine species which colonize brackish environments in the outer and intermediate areas of the estuary and of brackish water species in the inner one. In the outer area different assemblages were attributed to different sediment types. This distribution pattern, put in relation to the distance from the sea, was evident in May and partly blurred in August and October: the assemblages of the inner area of the estuary invaded the intermediated area in August and affected outer area in October because of spreading of the brackish water species S. shrubsolii, which became dominant. The distribution pattern of molluscs and polychaetes can be explained in terms of confinement as the leading factor influencing water quality and dynamics of the ecosystem. It is also needed to be taken into consideration the role played by competition due to different degree of opportunism of the most abundant species.

M-AMBI revisited: looking inside a widely-used benthic index

M-AMBI is a multimetric index for assessing the ecological quality status of marine and transitional waters. It is based on benthic macroinvertebrates and integrates AMBI, a biotic index based on species sensitivity/tolerance, with diversity and richness, making it compliant with the European Water Framework Directive. The success of AMBI paved the way for the introduction of M-AMBI, which was subsequently incorporated into the regulations of several European countries. The M-AMBI algorithm integrates the metrics by means of factor analysis (FA). In this paper, we first reproduced the algorithm using the open source R software. This enabled us to point out that FA is not functional to M-AMBI, and its omission does not appreciably change the results. We then enhanced the applicability of the index, making it independent of the number of samples. In this way, M-AMBI is closely approximated by the simple mean of the normalised metrics with no need for multivariate techniques. Finally, we further simplified the approach, presenting a bivariate version that is still highly correlated with M-AMBI, in which the constitutive metrics are reduced to a diversity measure and a species sensitivity index. The properties of this bivariate version include simplicity, transparency, robustness, and openness.

A new geographical record of Polycera hedgpethi Er. Marcus, 1964 (Nudibranchia: Polyceridae) and evidence of its established presence in the Mediterranean Sea, with a review of its geographical distribution

Abstract This article reports the first record of the Nudibranch Polycera hedgpethi in the Lagoon of Venice (Italy), as well as its established presence in the Mediterranean Sea after its first record in 1986 in lake Fusaro (Naples). In less than 50 years P. hedgpethi has spread throughout the worlds temperate and subtropical waters, preferring protected coastal environments and other semi-enclosed coastal water bodies such as ports, harbours and lagoons. Shipping is the most likely vector. The species distribution shows a temperate–subtropical range, at about 7–45° of latitude both North and South. Polycera hedgpethi was collected during a survey in 2009 and its presence confirmed for the following two years. All individuals collected were found attached to the bryozoan Bugula neritina, to which it is linked trophically, suggesting a determined pattern of distribution. The present finding is the northernmost record for the species.

Open Nomenclature in the biodiversity era

Summary The uncertainty or the provisional status of a taxonomic identification can be expressed by a set of terms and abbreviations known as Open Nomenclature (ON) qualifiers. This approach is widely applied across biological disciplines, and a high amount of biodiversity data left in ON can be found in literature and data bases. However, there is no consensus about ON qualifiers and their meaning. The use of ON qualifiers has been reviewed in order to provide a summary and guide to current practice in zoology. Some recommendation is given to avoid inconsistencies or vagueness. A flow chart is proposed to clarify the sources of uncertainties during identification and to facilitate the application of ON qualifiers. This review provides a guide for taxonomists and ecologists currently involved in biomonitoring and biodiversity programmes, as well as for researchers dealing with biodiversity data infrastructures and tools, offering a starting point for a methodological harmonization.

The non-indigenous Paranthura japonica Richardson, 1909 (Isopoda: Anthuroidea: Paranthuridae) from the Mar Piccolo lagoon, Taranto (Italy, Mediterranean Sea).

Several individuals of Paranthura japonica, a non-indigenous isopod species, recently recorded on Italian coasts, have been collected from the Mar Piccolo basin, Taranto (Italy). This finding extends the distributional range of the species southwards in the Mediterranean, including a semi-enclosed coastal basin, which is considered the second Italian hotspot for the introduction of alien species. The characteristics of the place reinforce the hypothesis that its introduction is linked to shellfish trade and farming. Remarks on the morphology and ecology are included.

High resolution multibeam and hydrodynamic datasets of tidal channels and inlets of the Venice Lagoon

Tidal channels are crucial for the functioning of wetlands, though their morphological properties, which are relevant for seafloor habitats and flow, have been understudied so far. Here, we release a dataset composed of Digital Terrain Models (DTMs) extracted from a total of 2,500 linear kilometres of high-resolution multibeam echosounder (MBES) data collected in 2013 covering the entire network of tidal channels and inlets of the Venice Lagoon, Italy. The dataset comprises also the backscatter (BS) data, which reflect the acoustic properties of the seafloor, and the tidal current fields simulated by means of a high-resolution three-dimensional unstructured hydrodynamic model. The DTMs and the current fields help define how morphological and benthic properties of tidal channels are affected by the action of currents. These data are of potential broad interest not only to geomorphologists, oceanographers and ecologists studying the morphology, hydrodynamics, sediment transport and benthic habitats of tidal environments, but also to coastal engineers and stakeholders for cost-effective monitoring and sustainable management of this peculiar shallow coastal system.

Clarifying the taxonomic status of the alien species Branchiomma bairdi and Branchiomma boholense (Annelida: Sabellidae) using molecular and morphological evidence

This study was performed to analyse the genetic and morphological diversity of the sabellid annelid genus Branchiomma, with special emphasis on a taxon so far identified as Branchiomma bairdi. This species, originally described from Bermuda, has frequently been reported as an invader in the Mediterranean, the Atlantic and the Eastern Pacific, but recent observations have raised some taxonomic questions. Samples of this taxon were collected from five sites in the Mediterranean Sea, two sites in the original distribution area of B. bairdi in the Gulf of Mexico and four localities in the east Pacific and Atlantic Oceans where B. bairdi has been reported as invasive. The molecular results revealed a conspicuous genetic divergence (18.5% K2P) between the sampled Mediterranean populations and all the other ones that led to a re-evaluation of their morphological characters. The latter showed that the Mediterranean and extra-Mediterranean populations also differ in some discrete morphological and reproductive features. Consequently, the Mediterranean samples were re-designated as B. boholense, another non-indigenous species originally described from Philippines. Branchiomma bairdi and B. boholense differ in body size, development and shape of micro and macrostylodes, size of radiolar eyes and body pigmentation. Genetic diversity was high in B. boholense from the Mediterranean as well as in B. bairdi from the Gulf of Mexico, but low in B. bairdi populations outside their native range. The phylogenetic analysis revealed the presence of connections between the Mediterranean localities as well as between native and introduced B. bairdi populations that focus the attention on the Panama Canal as important passage for the introduction of the species from the Gulf of Mexico to the north-east Pacific Ocean.