Abstract
A study on macrobenthos of Acquatina Lake, a transitional water basin, was performed in order to evaluate its present status and detect any faunistic changes after the digging of a larger connection with the open sea that has improved the hydrological conditions. A total of 5029 individuals belonging to 51 taxa were collected. Molluscs were taxonomically the richest group, but polychaetes were the most abundant due to the high abundance of Heteromastus filiformis . The sites representing two extremes of the biotope in terms of both the salinity gradient and the distance from the sea had the most variable assemblages, while the central area showed a more homogeneous faunal composition. This was due to the different distribution patterns of molluscs and polychaetes: the former seemed to be more influenced by salinity, while the latter were also influenced by oxygen saturation. The comparison between the present and historical data showed the increase of polychaete diversity, the change in the dominant taxa (from Naineris laevigata to H. filiformis ) and the disappearance of some opportunistic forms (e.g. Capitella capitata ). Changes in the salinity gradient and the improvement of trophic conditions, possibly enhanced by biotic interactions (e.g. possible competition between the two capitellids H. filiformis and Notomastus latericeus ), may have led the polychaete assemblage towards the new equilibrium.
Highlights
At temperate latitudes, brackish-water benthic assemblages often undergo drastic fluctuations in both species abundance and richness due to physical-chemical variability (Arvanitidis et al, 1999), which can be cyclic or episodic (Boero, 1996; Giangrande and Fraschetti, 1996)
Modifications requiring decades in more stable marine communities can happen in only a few years in transitional water environments (Nicoletti et al, 2006)
The present paper describes the soft-bottom benthic assemblages of the Acquatina Lake, a typical xeroMediterranean biotope (Bianchi and Zurlini, 1984) located in the Salento peninsula along the Southern Adriatic coast
Summary
Brackish-water benthic assemblages often undergo drastic fluctuations in both species abundance and richness due to physical-chemical variability (Arvanitidis et al, 1999), which can be cyclic (predictable, e.g. seasonal) or episodic (unpredictable) (Boero, 1996; Giangrande and Fraschetti, 1996). Species colonising these environments are highly adapted to extreme conditions, 236 R. The difficulty in obtaining long-term data limits studies of this type of change (Gray and Christie, 1983; Salen-Picard and Arlhac, 2002) In this context, brackish-water environments might be ideal models for assessing directional changes in the assemblages’ structure. Modifications requiring decades in more stable marine communities can happen in only a few years in transitional water environments (Nicoletti et al, 2006)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
