0000000001225471
AUTHOR
R. Chemello
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…
Bi- and three-dimensional fractal analysis of the brown seaweed Gongolaria montagnei and their relationship with gastropod molluscs assemblage
Habitat complexity is one of the main influences on biodiversity in marine environments, particularly in coastal areas where foundation seaweeds provide substrate for highly diverse communities. We studied the 2D and 3D fractal dimensions of Gongolaria montagnei (Fucales) over the vegetative season and examine their relationship with the abundance, species richness and morpho-functional groups of the gastropod associated. Overall, the 3D fractal analysis method used here better describes seaweeds structural complexity compared to the traditional 2D fractal analysis, as highlighted by the higher relationship with gastropod assemblage associated to the alga in terms of abundance, number of sp…
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…
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…
Settlement performance of the Mediterranean reef-builders Dendropoma cristatum (Biondi 1859) in response to natural bacterial films
The gastropod Dendropoma cristatum is a biogenic engineer of the central Mediterranean, forming reefs along the lower rocky intertidal fringe with a remarkable ecological role. To understand whether reef-associated biofilm cultivable bacterial and biofilm ageing may trigger the settlement of the juvenile snails, a combination of laboratory techniques and field experiments was used. Reef-associated biofilm cultivable bacteria were isolated, and a settlement-choice experiment was performed in situ on artificial biofilms composed of i) a mixture of six biofilm-forming selected isolates, ii) all the cultivable bacteria, and iii) 13-, 23-, 32-day old biofilms formed under naturalconditions. Overall,sett…
SPATIAL DISTRIBUTION OF DENDROPOMA CRISTATUM (MOLLUSCA, GASTROPODA) ADULT BIOMASS ON A VERMETID REEF
A spatial characterization of Dendropoma cristatum biomass was carried out on a Vermetid reef in north-western Sicily. Biomass distribution of adult specimens is not homogenous in the different areas of the reef, with an increasing trend from the inner edge to the outer edge, while the central pool supports intermediate values of vermetid biomass. Considering the entire reef area, the cuvette has the highest Dendropoma biomasses of the bioconstruction, even if the highest surface-biomass ratio is found in the outer edege.
Sea level rise in the Mediterranean Sea: High resolution constraints from vermetid reefs
The Mediterranean Sea (MS), is extremely sensitive to rising sea-levels (SL) as attested by drowned archeological remains from the Roman Period [2]. Due to the absence of coral reefs, evidence for recent and Holocene SL change has so far mainly been restricted to coastal cores [1] archeological remains [2] and submerged speleothem deposits. Vermetid reefs are an extremely sensitive high resolution carbonate archive [3,4] and they are mainly formed in the lower intertidal zone by gregarious and sessile gastropods belonging to the genus Dendropoma (family Vermetidae). Since their interval of growth is restricted to the tidal zone, they can be used as precise SL proxies (about ±0.1 m in low ra…
Finding of a living population of Panopea glycimeris (Von Born, 1778) (Bivalvia; Hiatellidae) in Eastern Sicily (Mediterranean Sea)
A consistent living population of Panopea glycimeris (von Born, 1778) was documented underwater along the eastern coast of Sicily. Twenty specimens were counted over an area of 1000 m(2), with an estimated total population of less than 300 individuals. The morphometric measurements of an adult specimen captured are provided. Proposals to adopt protection measures for this species are discussed.
COASTAL ACCESSIBILITY AS VULNERABILITY FACTOR FOR PATELLA ULYSSIPONENSIS GMELIN, 1791 IN A MEDITERRANEAN MPA
Average density of Patella ulyssiponensis Gmelin, 1791 was correlated with costal accessibility and tourists’ density. The results highlighted that the accessibility could have a greater weight than the MPA regulation, in absence of patrolling, on the vulnerability of this sensitive species.