Effects of structural complexity on epifaunal assemblages associated with two intertidal Mediterranean seaweeds

Brown foundation seaweeds are key elements increasing substrate heterogeneity and shaping the biodiversity in rocky coastal ecosystems. They are, however, vulnerable species that are declining due to multiple anthropogenic and climate change stressors, leading to a shift to less structural complex habitats. We investigate the role of structural attributes of two intertidal macroalgae, Ericaria amentacea and Laurencia obtusa, in shaping the abundance and diversity of their associated epifaunal assemblages. For this aim, we measured seaweeds’ biomass, thallus volume and length (used here as proxy of substrate complexity), and explored which seaweeds’ substrate attribute explained better varia…

A SMALL INVADER CONQUERS SICILY: AMPHISTEGINA LOBIFERA (FORAMINIFERA: AMPHISTEGINIDAE)

The highly invasive Amphistegina lobifera (Larsen, 1976), a benthic foraminiferal species native to the Red Sea, has colonized the Eastern Mediterranean through the Suez Canal and altered the native community structure. More recently, it has been reported from Malta and the Pelagian Islands within the Sicily channel. Here, we report new records from the southern coasts of Sicily, where we found it abundant both in the soft-bottom sediment and as epiphyt on algae. The occurrence of A. lobifera in Pantelleria and Favignana islands represents the Mediterranean westernmost record of this non-indigenous species.

Invasive Amphisteginids conquer the Sicily Channel and knock on the door of the Western Mediterranean Sea

This study reports an updated overview of the current distribution and establishment status of the invasive species Amphistegina lobifera Larsen, 1979 and of other non-indigenous foraminifera in the Sicily Channel. The dispersal of marine non-indigenous species (NIS) by human activities is redefining the biogeography of the oceans and is one aspect of global change. Understanding the role of NIS in altering the structure of marine communities requires accurate information on their temporal occurrence, spatial distribution and effect on native ecosystems. However many NIS, particularly those belonging to small-sized unicellular taxa, such as benthic foraminifera, are largely unrecognized and…

Structure and composition of intertidal biofilms which enhance the settlement of the central-Mediterranean reef builder Dendropoma cristatum (Biondi 1859).

Introduction Marine biofilms are complex matrix of microorganisms and mucopolysaccharide substances which develop on all submerged surfaces, providing a variety of physical-bio-chemical cues which affect the settlement of a wide range of benthic organisms. Biofilm community composition, 3-D structure and metabolic activity vary over time. Few studies report the biological and physical changes in marine biofilm development in relationship to their effects on benthic colonisation. Biofilm maturity has been reported to enhance the settlement rate of the central-Mediterranean Dendropoma cristatum (Biondi, 1859), an intertidal vermetid gastropod which builds up ecologically relevant reefs, subje…

Bioactive compounds from brown algae inhabiting the north-western Mediterranean Sea

Marine algae produce a great amount of secondary metabolites (e.g. terpenoids, fatty acids, steroids, polysaccharides and polyphenols) to face environmental stressors they are exposed to, but also to defend themselves from biological pressures such as competitors, pathogens, grazers and epiphytes. Over the last decade, secondary metabolites isolated from brown algae and phenolic compounds, in particular, are receiving increasing attention due to their putative ecological roles, and several biological properties. Brown fucoid algae of the genus Cystoseira sensu latu (Sargassaceae) and Dictyotaceae produce a wide variety of secondary metabolites which have been investigated mainly for their d…

Effetto dell’impatto antropico e geometria del substrato sulla distribuzione e struttura delle comunità bentoniche vegetali di fouling

How do non-indigenous species affect native species and habitats?

Biological invasions are a key driver of global change, affecting biodiversity and natural ecosystem functioning. Non-indigenous species (NIS) with significant established and expanding populations have the potential to become invasive, with serious environmental, socio-economic, and/or human health consequences. Mediterranean Islands (including Marine Protected Areas “MPAs”), important hotspots of biodiversity, are particularly vulnerable to NIS invasions. Understanding the effects of NIS species on biodiversity, as well as their current distribution and expansion trends, is therefore critical for creating effective conservation strategies. Here, we present three different case studies fro…

Marine macrophytes: diversity and applications

The research activity deals with several aspects of biology, systematics and ecology of marine macrophytes, with a special focus on macrophytes inhabiting the Mediterranean Sea. In particular, the research focuses on: 1) Marine alien macrophytes (e.g. Caulerpa, Asparagopsis, Halophila) and their interactions with autochthonous macrophytes, with particular attention to Marine Protected Areas. 2) Coralline red algae (Rhodoliths, Lithophyllum byssoides), characterized by a carbonate thallus, which form complex structures that increase the habitat biodiversity and are a key component in the cycle of carbonate budget. Thus, they are of high interest for conservation. 3) Brown algae belonging to …

Environmental quality assessment of the Sicilian coast using a multi-disciplinary approach

A multidisciplinary approach for the assessment of the environmental quality of the Sicilian coast is presented. This approach can be adopted for any Mediterranean coastline. The territory was divided into elementary areas and for each of them we reported the most important taxa, belonging to fauna and vascular, bryophytic and algal flora, from a biogeographic point of view in order to evaluate punctual and general levels of biodiversity conservation. The comparative analysis showed that the main circumsicilian islands and the carbonate promontories of the Tyrrhenian coast present the highest degree of biodiversity. The coastal lagoons located in the south-eastern Sicily, even though charac…

CAN HALOPHILA STIPULACEA OUTCOMPETE CYMODOCEA NODOSA? A CASE STUDY OF A MEDITERRANEAN SHALLOW WATER HABITAT

The tropical seagrass Halophila stipulacea (Forsskål) Ascherson entered the Mediterranean Sea through the Suez Canal more than 100 years ago. In the coastal-marine ecosystems the spatial niche of H. stipulacea is often overlapped with that of native Mediterranean Sea seagrasses and therefore it might out-compete them. On the basis of previous observations, we monitored for one year a Southern Mediterranean shallow water habitat (North-Western Sicily Island, Italy, Southern Mediterranean Sea), where H. stipulacea co-occurred with the native seagrass Cymodocea nodosa (Ucria) Ascherson. In this paper we compare sites with (impacted sites) and without H. stipulacea (non-impacted sites) to analy…