Markos Digenis

Ionian University | IONIO · Department of Environmental Sciences

Marine caves constitute vulnerable habitats with unique and diverse biocoenoses. Monitoring these habitats is still challenging, which hinders the ability to evaluate global and local pressures that threatens their ecological value. In this study, ecological quality is estimated in twenty-one marine caves distributed along the northern and southern...

Molecular methods such as DNA/eDNA metabarcoding have emerged as useful tools to document biodiversity of complex communities over large spatio-temporal scales. We established an international Marine Biodiversity Observation Network (ARMS-MBON) combining standardised sampling using autonomous reef monitoring structures (ARMS) with metabarcoding for...

Groundwater ecosystems are inhabited by unique assemblages of animals, often with restricted distributions and highly specialized traits. Those assemblages sustain ecosystem functioning and contribute to important ecosystem services. Knowledge of the species occurring in those habitats and the main ecological and historical drivers for their distri...

This Collective article presents 18 introduced taxa in the Mediterranean Sea, belonging to seven phyla and documented at 22 new locations and seven countries spanning from the Levantine to the western Mediterranean. These records include the first country records of the African mussel Perna perna (Syria), the sea slug species complex Elysia cf. mar...

This Collective Article presents information about 30 species with records in eight countries (Greece, Israel, Italy, Montenegro, Slovenia, Spain, Syria and Türkiye) and six ecoregions extending from the Alboran to the Levantine Seas. The recorded species belong to eight Phyla (4 Chlorophyta, 1 Rhodophyta, 1 Porifera, 3 Cnidaria, 2 Platyhelminthes,...

Marine and anchialine caves host specialized faunal communities with a variable degree of endemism and functional specialization. However, biodiversity assessments on this habitat are scarce, particularly in relation to small-sized cryptic fauna (such as amphipods), which often play a key role in benthic ecosystems. The present article compiles all...

To understand global shifting trends in marine biodiversity it is essential to apply cost-efficient biomonitoring approaches in a coordinated and standardized manner, to generate comparable data across geographical regions and countries. In this context, DNA metabarcoding is particularly useful to document biodiversity over larger spatiotemporal sc...

Τα μουσεία φυσικής ιστορίας, πέρα από εκθεσιακούς χώρους εκπαίδευσης και ψυχαγωγίας, φιλοξενούν αρχεία και ζωολογικές συλλογές μεγάλου ερευνητικού ενδιαφέροντος. Ειδικότερα, οι μικρές ιδιωτικές συλλογές συχνά συγκε- ντρώνουν δεδομένα βιοποικιλότητας και τοπικής γνώσης που παραμένουν αδημοσίευτα και μη προσβάσιμα για την ευρύτερη επιστημονική κοινότ...

Marine caves support rich biodiversity with sponges presenting an important functional role as ecosystem engineers and constituting the most representative colonizers of their darker interior. Although plenty of marine caves have been reported on the Croatian coastline, they are mostly qualitatively studied. In the current study, one semi-submerged...

This paper proposes a data-driven methodology framework to enrich existing biodiversity data by collecting crowd-sourced knowledge contributed by citizens in the form of photographs. The framework aims to provide the design of an easy-to-use web interface tool that clusters biodiversity images from multiple data sources. Through its design it will...

Octocoral forests created by the yellow sea fan Eunicella cavolini and the red sea fan Paramuricea clavata were studied at the National Marine Park of Alonissos Northern Sporades (Aegean Sea, Greece), between 30 and 45 m depth, in order to assess their conservation status and the occurrence of both natural and anthropogenic stressors. The area was...

To enrich spatio-temporal information on the distribution of alien, cryptogenic, and neonative species in the Mediterranean and the Black Sea, a collective effort by 173 marine scientists was made to provide unpublished records and make them open access to the scientific community. Through this effort, we collected and harmonized a dataset of 12,64...

This Collective Article presents information on 20 taxa belonging to five (5) Phyla: Cnidaria (2), Mollusca (8), Arthropoda (4), Echinodermata (1) and Chordata (5) recorded from the Alboran Sea to the Levantine Sea. These new records were found in seven (7) different ecoregions as follows: Alboran Sea: new record of the rare football octopus Ocytho...

Highlight Here we describe our mapping results, for the updated stratigraphy of the Plattenkalk unit, and the tectonic contacts in Small Trocharis Mountain at northeast Lefka Ori of the island of Crete. The most prominent finding is that in the northeast , close to the peak of Ag Pneuma Melidoniou the thin bedded marble with silex (upper Jurassic-E...

Brachiopods, though common in marine caves, have been so far rarely reported from caves of the Eastern Mediterranean Sea. Herein we present new records of brachiopods collected in eleven marine caves located on eight Greek islands (Kastelorizo, Rhodes, Crete, Samos, Agios Efstathios, Polyaigos, Pantieronissi and Skyros). Four species (60 individual...

Although Mediterranean marine caves have been characterized as biodiversity reservoirs and vulnerable habitats, little is known about the threats they may face. The invasive macroalgae Rugulopteryx okamurae is rapidly spreading along the Western Mediterranean Sea displacing native sessile competitors through space monopolization but also negatively...

Marinas receive a multitude of anthropogenic impacts such as marine pollution, high turbulence and biological invasions via transport-stowaway and can function as stepping stones for the dispersal of non-indigenous species (NIS). Although Greece has a high number of marinas, little is known about their benthic communities. The current study aims to...

Herein we present new records of brachiopods collected in eleven marine caves located on eight Greek islands (Kastelorizo, Rhodes, Crete, Polyaigos, Agios Efstathios, Pantieronissi, Samos and Skyros), spanning from the Levantine to the North Aegean Sea. None of these caves had been studied before for its brachiopod diversity. Qualitative samples (6...

The "Guide for Marine Habitat Mapping" is the outcome of the Green Fund project entitled "Development of common methodology and techniques for marine habitat mapping". This Guide aims to provide a synopsis of the diverse array of concepts and methods used to undertake the marine habitat mapping adapted to the marine environment of the Hellenic Seas...

Although Mediterranean marine caves have been characterized as biodiversity reservoirs and vulnerable habitats, little is known about the threats they may face. The invasive macroalgae Rugulopteryx okamurae is rapidly spreading along the Western Mediterranean Sea displacing native sessile competitors through space monopolization but also negatively...

The Sternes cave is located on the Lefka Ori massif of Crete at the altitude of 2095m. The cave was explored in the early nineties by GSO, but abandoned in 1992. Greek teams ‘rediscovered’ the cave in 2005 and until 2012, conducted numerous expeditions (some international), to clear the meander at ‐428m. The fact that the two deepest caves in Greec...

Although more than 600 marine caves have been recorded so far along the Greek coasts of the Aegean Sea (Eastern Mediterranean), only a few have been systematically studied for their biodiversity. In this study, the benthic communities of six marine caves within a Protected Area of South-Eastern Aegean were studied for the first time, both qualitati...

Although marine caves are considered as biodiversity reservoirs, little is known about their mobile inhabitants. Thus, in the framework of the research program ALAS, both the abundance and species richness of mobile fauna were recorded at 12 marine caves across the Aegean Sea. A total of 14 alien species were recorded with higher abundance at the s...

This Collective Article presents information about 27 taxa belonging to five Phyla (one Ochrophyta, one Cnidaria, three Arthropoda, two Mollusca and twenty Chordata) and extending from the Western Mediterranean Sea to the Levantine Sea and the Black Sea (Sea of Marmara). The new records were reported from 11 countries as follows: Algeria: occurrenc...

Intertidal ecosystems are key habitats that are being replaced by artificial hard substrates due to the increment of human activities in coastal areas. These new substrates host generally less biodiversity mainly due to differences in complexity and composition. It is a global phenomenon and has led to the development of strategies in the framework...

Data on the distribution and ecology of cryptobenthic fish of marine caves in the Mediterranean Sea are extremely scarce but necessary for scientists and marine managers alike in order to understand these fish’s ecological role and assess their conservation status. Broadscale surveys by implementing underwater visual census and photographic samplin...

Sea caves constitute underwater cavities of various forms mostly filled with sea water. From the first studies on marine caves in the early 1950’s, scientists recorded a rich biodiversity in their interior unveiling new information about this unique marine ecosystem. Marine caves were soon considered as a habitat of European interest (type 8330 in...

Urocaridella pulchella Yokeş & Galil, 2006 is a palaemonid cleaner-shrimp of Indo-Pacific origin that was first described from the Mediterranean Sea in 2006. However, limited information is available about its distribution and ecology due to the small size and cryptic habit of the species. We hereby report the first records of U. pulchella in marin...

This article includes 23 new records of alien and cryptogenic species in the Mediterranean Sea, belonging to 4 Phyla (Chordata, Echinodermata, Arthropoda and Mollusca), distributed from the Alboran to the Levantine Sea. Records are reported from eight countries listed from West to East as follows: Algeria: new records of the Atlantic blue crab Call...

Good datasets of geo-referenced records of alien species are a prerequisite for assessing the spatio-temporal dynamics of biological invasions, their invasive potential, and the magnitude of their impacts. However, with the exception of first records on a country level or wider regions, observations of species presence tend to remain unpublished, b...

Good datasets of geo-referenced records of alien species are a prerequisite for assessing the spatio-temporal dynamics of biological invasions, their invasive potential, and the magnitude of their impacts. However, with the exception of first records on a country level or wider regions, observations of species presence tend to remain unpublished, b...

The lobate ctenophore Leucothea multicornis (Quoy & Gaimard, 1824) was recorded off Kefalonia Island , Greece, in July 2019. This new record, in the Eastern Ionian Sea, fills distribution gaps between the central Mediterranean basin and the Levantine Sea.

The present BSc diploma thesis aims to study the macrobenthic marine biodiversity of the submerged Elephant Cave both qualitatively and quantitatively, using different methods. Futhermore, it aims to explore potential correlations of the spatial distribution patterns of biodiversity with that of certain environmental parameters related to water and...

Marine caves constitute unique biodiversity reservoirs of high conservation value. Nevertheless, marine caves of the Aegean Sea have been studied less intensively than those in other Mediterranean regions. In this study, benthic biodiversity and physicochemical parameters were investigated for the first time in the Elephant Cave of Crete (Greece),...

Two decades ago, a unique marine cave was discovered in Crete (Greece, Eastern Mediterranean). The so-called Elephant Cave was very soon meant to become one of the most iconic diving destinations in the island. It stands out for its aesthetic value with a variety of speleoforms and the remaining fossil bones of deers and a dwarf elephant which are...