Checklist of free-living nematode species in the transitional environment of Lake Varano (Southern Italy)

Dipto Di Scienze Della Terra, Della Vita E Dell’ambiente (Disteva), Univ Di Urbino, Italy ,F Semprucci,M Balsamo

doi:10.32800/amz.2015.13.0032

Abstract

This study documents for the first time the taxonomic composition of the nematode community and the number of free–living nematode species in Lake Varano, Southern Adriatic Sea, Italy. The nematode community was mainly composed of species typical of fine sediments that usually prevail in transitional environments (TEs). An overall high number of nematode species was recorded (55), belonging to 36 genera in 17 families. These values are highly comparable to those reported for other Italian TEs, but appear lower than those recorded in other European brackish–water systems, probably in relation to the low salinity range of Lake Varano. Forty taxa were identified up to species level, thus increasing the number of the nematode marine species known for the Italian coasts from 443 to 463, for the Adriatic basin from 310 to 313, and for the Southern Adriatic sector from 37 to 77. Considering the importance of this phylum in the assessment of ecological quality and the great vulnerability of the Adriatic Sea ecosystems, an intensification of sampling efforts should be planned, especially in the Central–Southern part of the basin. Such a plan would provide new insights into the biogeography of one of the most important components of the benthic domain and potentially yield new information about the climate warming effects on the Adriatic Sea.

Highlights

Transitional environments (TEs) are aquatic systems characterized by large fluctuations of physicochemical and geochemical variables that could greatly affect the benthos (Barnes et al, 2008; Frontalini & Coccioni, 2011)
Fifty–five nematode species belonging to 36 genera and 17 families were found at Lake Varano
Given its particular physico–chemical features, the Adriatic Sea is strongly influenced by meteorological conditions and river discharges, and it is sensitive to human impact and climatic changes (Occhipinti–Ambrogi et al, 2005; Balsamo et al, 2010; Fron talini et al, 2011)

Summary

Introduction

Transitional environments (TEs) are aquatic systems characterized by large fluctuations of physicochemical and geochemical variables that could greatly affect the benthos (Barnes et al, 2008; Frontalini & Coccioni, 2011). The Adriatic Sea coast, in particular, hosts a large amount of TEs, ranging from the largest and most studied Lagoon of Venice to wetlands, estuaries, embayments and ponds. All these habitats have been modified to meet human requirements for millennia and are currently under severe stress due to anthropogenic activities and climate change (Airoldi & Beck, 2007). The phylum Nematoda is the most diverse and numerically dominant component of the aquatic ecosystems (Balsamo et al, 2010; Appeltans et al, 2012). Nematodes are well recognized as a useful tool for biomonitoring assessment of marine ecosystems (Balsamo et al, 2012; Semprucci et al, 2015). Many studies of meiofaunal communities have been carried out in Italian TEs, but they generally concern a higher taxonomic level of identification (Colangelo & Ceccherelli, 1994; Colangelo et al, 1996; Guerrini et al, 1998; Fiordelmondo et al, 2003; Gambi et al, 2003; Fabbrocini et al, 2005; Pusceddu et al, 2007; Cibic et al, 2012)

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Conclusion