New Alien Mediterranean Biodiversity Records (August 2022)

In this Collective Article on alien and cryptogenic diversity in the Mediterranean Sea we report a total of 19 species belonging to nine Phyla and coming from nine countries. Several of these records concern fish species, and of particular interest are the first records of: Terapon puta for Italian waters; Pteragopus trispilus from Malta; Plotosus lineatus from Cyprus; and the northernmost Mediterranean record of Lagocephalus sceleratus. The northernmost Mediterranean record was also reported for the sea urchin Diadema setosum. The portunid crab Thalamita poissonii was recorded for the first time in Libya. The copepod Pseudodiaptomus marinus was recorded for the first time in the Marmara Sea. The polychaete Branchiomma luctuosum was recorded for the first time from the Mediterranean coast of France. The alien anemone Diadumene lineata was recorded for the first time from Slovenia. The macroalgae Sargassum furcatum was recorded for the first time from Italy. The new Mediterranean records here reported help tracing abundance and distribution of alien and cryptic species in the Mediterranean Sea

Unpublished Mediterranean and Black Sea records of marine alien, cryptogenic, and neonative species

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species in the Mediterranean and the Black Sea, a collective effort by 173 marine scientists was made to provide unpublished records and make them open access to the scientific community.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 12,649 records. It includes 247 taxa, of which 217 are Animalia, 25 Plantae and 5 Chromista, from 23 countries surrounding the Mediterranean and the Black Sea. Chordata was the most abundant taxonomic group, followed by Arthropoda, Mollusca, and Annelida. In terms of species records, Siganus luridus, Siganus rivulatus, Saurida lessepsianus, Pterois miles, Upeneus moluccensis, Charybdis (Archias) longicollis, and Caulerpa cylindracea were the most numerous. The temporal distribution of the records ranges from 1973 to 2022, with 44% of the records in 2020–2021. Lethrinus borbonicus is reported for the first time in the Mediterranean Sea, while Pomatoschistus quagga, Caulerpa cylindracea, Grateloupia turuturu, and Misophria pallida are first records for the Black Sea; Kapraunia schneideri is recorded for the second time in the Mediterranean and for the first time in Israel; Prionospio depauperata and Pseudonereis anomala are reported for the first time from the Sea of Marmara. Many first country records are also included, namely: Amathia verticillata (Montenegro), Ampithoe valida (Italy), Antithamnion amphigeneum (Greece), Clavelina oblonga (Tunisia and Slovenia), Dendostrea cf. folium (Syria), Epinephelus fasciatus (Tunisia), Ganonema farinosum (Montenegro), Macrorhynchia philippina (Tunisia), Marenzelleria neglecta (Romania), Paratapes textilis (Tunisia), and Botrylloides diegensis (Tunisia).peer-reviewe

Ecological and population status of european ground squirrel (Spermophilus citellus Linnaeus, 1766) in Greece

The European ground squirrel is an endangered semifossorial squirrel-like rodent of the European grassland ecosystems. In recent decades its population has been declining throughout its range. Greek populations represent the southernmost limit, whereas the knowledge of their status is limited. The aim of this PhD thesis is to study the population, ecology, genetics, and ethology of the species in Greece. From field visits during 2019-2020 in Western and Central Macedonia and Thrace, data on occurrence, biological tissue and vigilance behaviour were collected. Data were analyzed using computational tools for population density analysis, habitat clustering, maximum entropy models of suitable and available habitats, genetic diversity indices, phylogenetic relations, and statistical likelihood ratio testing. The results revealed that: (a) The results showed that: (a) the existing colonies had a low average density and number of individuals. Most colonies were located on small agricultural and artificial surfaces in the lowlands of Central Macedonia and Thrace. The populations of Western Macedonia were distinguished due to the different topographical and climatic conditions; (b) both anthropogenic and bioclimatic factors have contributed to the pattern of population distribution, with available habitat being scarce compared to suitable habitat. In addition, a 39% - 94.3% decline in habitat suitability was predicted due to climate change over the next 40 years; (c) the genetic diversity of Greek populations was not correlated with latitude after comparison with Serbian populations. Considering all the samples from the European distribution, it appeared that the earlier populations of the species were located in southeastern Bulgaria and European Turkey and during the post-glacial period they rapidly expanded towards Greece, namely from Thrace to Central and Western Macedonia; (d) adult individuals were more vigilant, following a different vigilance strategy depending on life cycle and habitat conditions, while young individuals were more risky due to high energy needs and lack of experience. In conclusion, conservation actions are proposed to protect the species' populations in Greece, identifying three in situ climatic refugia that could be a priority for future reintroductions and habitat improvement.Ο ευρωπαϊκός λαγόγυρος είναι ένα κινδυνεύον με εξαφάνιση εδαφόβιο σκιουροειδές τρωκτικό των χορτολιβαδικών οικοσυστημάτων της Ευρώπης. Τις τελευταίες δεκαετίες ο πληθυσμός του παρουσιάζει πτωτική τάση σε όλο το εύρος εξάπλωσης. Οι ελληνικοί πληθυσμοί αντιπροσωπεύουν το νοτιότερο όριο, ενώ η γνώση της κατάστασής τους είναι περιορισμένη. Σκοπός της παρούσας διδακτορικής διατριβής είναι η μελέτη του πληθυσμού, της οικολογίας, της γενετικής και της ηθολογίας του είδους στην Ελλάδα. Από επιτόπιες επισκέψεις μεταξύ 2019-2020 σε Δυτική και Κεντρική Μακεδονία και Θράκη συλλέχθηκαν δεδομένα παρουσίας, βιολογικού ιστού και επαγρύπνησης. Τα δεδομένα αναλύθηκαν με υπολογιστικά μέσα ανάλυσης της πληθυσμιακής πυκνότητας, ομαδοποίησης των ενδιαιτημάτων, μοντέλα μέγιστης εντροπίας κατάλληλων και διαθέσιμων ενδιαιτημάτων, δεικτών γενετικής ποικιλότητας, φυλογενετικών σχέσεων και στατιστικού ελέγχου του λόγου των πιθανοτήτων. Τα αποτελέσματα έδειξαν ότι: (α) οι υφιστάμενες αποικίες είχαν μικρή μέση πυκνότητα και αριθμό ατόμων. Η πλειονότητα των αποικιών εντοπίστηκε σε αγροτικές και τεχνητές επιφάνειες μικρής έκτασης στα πεδινά της Κεντρικής Μακεδονίας και Θράκης. Οι πληθυσμοί της Δυτικής Μακεδονίας ξεχώρισαν λόγω των διαφορετικών τοπογραφικών και κλιματικών συνθηκών· (β) τόσο ανθρωπογενείς όσο και βιοκλιματικοί παράγοντες συνέβαλαν στο πρότυπο εξάπλωσης των πληθυσμών, με τα διαθέσιμα ενδιαιτήματα να είναι ελάχιστα σε σχέση με τα κατάλληλα. Επιπλέον, προβλέφθηκε μείωση της καταλληλότητας των ενδιαιτημάτων κατά 39% – 94,3%, εξαιτίας της κλιματικής αλλαγής της επόμενης 40ετίας· (γ) η γενετική ποικιλότητα των ελληνικών πληθυσμών δε συσχετίστηκε με το γεωγραφικό πλάτος έπειτα από τη σύγκριση με σέρβικους πληθυσμούς. Λαμβάνοντας υπόψη το σύνολο των δειγμάτων από την ευρωπαϊκή εξάπλωση, φάνηκε ότι οι προγενέστεροι πληθυσμοί του είδους βρίσκονταν στη νοτιοανατολική Βουλγαρία και την Ευρωπαϊκή Τουρκία και κατά τη μεταπαγετώδη περίοδο επεκτάθηκαν ταχύτατα προς την Ελλάδα και συγκεκριμένα από τη Θράκη στην Κεντρική και Δυτική Μακεδονία· (δ) τα ενήλικα άτομα ήταν πιο επιφυλακτικά ακολουθώντας διαφορετική στρατηγική επαγρύπνησης ανάλογα με τον κύκλο ζωής και τις συνθήκες της περιοχής, ενώ τα νεαρά διακινδυνεύαν περισσότερο εξαιτίας των υψηλών ενεργειακών αναγκών και της απειρίας. Συμπερασματικά, προτείνονται δράσεις διατήρησης για την προστασία των πληθυσμών του είδους στην Ελλάδα, προσδιορίζοντας τρία in situ κλιματικά καταφύγια που θα μπορούσαν να αποτελέσουν προτεραιότητα για μελλοντικές επανεισαγωγές και βελτίωση των ενδιαιτημάτων

Distribution, Population Size, and Habitat Characteristics of the Endangered European Ground Squirrel (Spermophilus citellus, Rodentia, Mammalia) in Its Southernmost Range

The European ground squirrel (Spermophilus citellus) is an endangered species, endemic to Central and Southeastern Europe, inhabiting burrow colonies in grassland and agricultural ecosystems. In recent years, agricultural land-use changes and increased urbanization have largely contributed to a severe population decline across its range, particularly in its southernmost edge. Assessing the population and habitat status of this species is essential for prioritizing appropriate conservation actions. The present study aims to track population size changes and identify habitat characteristics of the species in Greece via a literature search, questionnaires, and fieldwork for assessing trends in population size as well as spatial K-means analysis for estimating its relation to specific habitat attributes. We found that both distribution size (grid number) and colony numbers of the species decreased in the last decades (by 62.4% and 74.6%, respectively). The remaining colonies are isolated and characterized by low density (mean = 7.4 ± 8.6 ind/ha) and low number of animals (mean = 13 ± 16 individuals). Most of the colonies are situated in lowlands and did not relate to specific habitat attributes. Habitat aspect and system productivity (NDVI) were the main factors contributing mostly to the clustering of the existing colonies. These results demonstrate that the species is confined to small, isolated anthropogenic habitats. Specific conservation actions such as population reinforcement, habitat improvement, and specific common agricultural policy measures could effectively improve agroecological zones that are suitable for the maintenance and protection of existing and potential habitats for populations of the species

Rise and fall: Results of a multidisciplinary study and 5-year long monitoring of conservation translocation of the European ground squirrel

The current publication gives a detailed assessment of the results from a population reinforcement of a European ground squirrel's (Spermophilus citellus) colony in south-eastern Bulgaria. The reinforcement was planned and implemented along with multidisciplinary research of the adaptation process (including radiotelemetry, parasitological study and assessment of the stress in the animals) and regular monitoring (yearly burrow counting). Although the donor and recipient populations were genetically similar, morphometrical data indicated variations in the body size probably due to the difference in population densities in the two sites. The monitoring revealed that the burrows were aggregated and there was a positive correlation in the spatial distribution of the ground squirrels’ burrow holes and the colonies of Harting's vole (Microtus hartingi) - another social ground-digging rodent that co-inhabits the study area. The first results showed successful reinforcement according to the three classical evaluation criteria: the individuals survived the translocation process, they successfully reproduced and an initial population growth was observed, based on the burrow entrances’ count - from 36 in 2017 to 280 in 2020. In 2021, however, a considerable decline in the abundance of the population was recorded - 58.5% decline in the burrow number and 36% decline in the colony area. A decrease was also observed in the abundance of the Harting's voles' colonies. A review of all the collected information suggests it is unlikely that the decrease is due to helminth parasites, translocation stress or other behaviour issues. The most probable explanation is the bad weather conditions - unusually high rainfalls combined with relatively high temperatures in January 2021. In conclusion, we strongly emphasise the need for detailed and long-term monitoring after conservation translocation and careful evaluation of all the influencing factors before, during and after such actions

European Ground Squirrels at the Edge: Current Distribution Status and Anticipated Impact of Climate on Europe’s Southernmost Population

The European ground squirrel (Spermophilus citellus) is an endangered semifossorial small mammal of grassland/agricultural ecosystems. In the last few decades, the species’ population has declined throughout its range in Europe. The Greek populations represent the southernmost limit of the species’ range and are notably small, scattered, and located mainly in human-modified areas. The goal of the present research is to understand the environmental and anthropogenic variables associated with its distribution in the Mediterranean habitats, assess possible drivers of observed local extinctions, and propose conservation and land-use management actions in light of near-future climate change scenarios. We used presence records since 2000 across all known populations (107 colonies) and maximum entropy conditional probability models (MaxEnt) to calculate both the habitat suitability (bioclimatic variables) and habitat availability (anthropogenic/land-use variables) within the European ground squirrel’s historical range in northern Greece. We report a projected 39% to 94.3% decrease in habitat suitability by 2040–2060 due to climate change. Based on our findings, we provide guidance by proposing nascent conservation actions to protect the few existing colonies in Greece via improved land management practices and identify in situ climate refugia that could be prioritized as sites for future reintroductions

European Ground Squirrels at the Edge: Current Distribution Status and Anticipated Impact of Climate on Europe’s Southernmost Population

The European ground squirrel (Spermophilus citellus) is an endangered semifossorial small mammal of grassland/agricultural ecosystems. In the last few decades, the species’ population has declined throughout its range in Europe. The Greek populations represent the southernmost limit of the species’ range and are notably small, scattered, and located mainly in human-modified areas. The goal of the present research is to understand the environmental and anthropogenic variables associated with its distribution in the Mediterranean habitats, assess possible drivers of observed local extinctions, and propose conservation and land-use management actions in light of near-future climate change scenarios. We used presence records since 2000 across all known populations (107 colonies) and maximum entropy conditional probability models (MaxEnt) to calculate both the habitat suitability (bioclimatic variables) and habitat availability (anthropogenic/land-use variables) within the European ground squirrel’s historical range in northern Greece. We report a projected 39% to 94.3% decrease in habitat suitability by 2040–2060 due to climate change. Based on our findings, we provide guidance by proposing nascent conservation actions to protect the few existing colonies in Greece via improved land management practices and identify in situ climate refugia that could be prioritized as sites for future reintroductions

New Alien Mediterranean Biodiversity Records (August 2022)

In this Collective Article on alien and cryptogenic diversity in the Mediterranean Sea we report a total of 19 species belonging to nine Phyla and coming from nine countries. Several of these records concern fish species, and of particular interest are the first records of: Terapon puta for Italian waters; Pteragopus trispilus from Malta; Plotosus lineatus from Cyprus; and the northernmost Mediterranean record of Lagocephalus sceleratus. The northernmost Mediterranean record was also reported for the sea urchin Diadema setosum. The portunid crab Thalamita poissonii was recorded for the first time in Libya. The copepod Pseudodiaptomus marinus was recorded for the first time in the Marmara Sea. The polychaete Branchiomma luctuosum was recorded for the first time from the Mediterranean coast of France. The alien anemone Diadumene lineata was recorded for the first time from Slovenia. The macroalgae Sargassum furcatum was recorded for the first time from Italy. The new Mediterranean records here reported help tracing abundance and distribution of alien and cryptic species in the Mediterranean Sea

Unpublished Mediterranean and Black Sea records of marine alien, cryptogenic, and neonative species

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 12,649 records. It includes 247 taxa, of which 217 are Animalia, 25 Plantae and 5 Chromista, from 23 countries surrounding the Mediterranean and the Black Sea. Chordata was the most abundant taxonomic group, followed by Arthropoda, Mollusca, and Annelida. In terms of species records, Siganus luridus, Siganus rivulatus, Saurida lessepsianus, Pterois miles, Upeneus moluccensis, Charybdis (Archias) longicollis, and Caulerpa cylindracea were the most numerous. The temporal distribution of the records ranges from 1973 to 2022, with 44% of the records in 2020–2021. Lethrinus borbonicus is reported for the first time in the Mediterranean Sea, while Pomatoschistus quagga, Caulerpa cylindracea, Grateloupia turuturu, and Misophria pallida are first records for the Black Sea; Kapraunia schneideri is recorded for the second time in the Mediterranean and for the first time in Israel; Prionospio depauperata and Pseudonereis anomala are reported for the first time from the Sea of Marmara. Many first country records are also included, namely: Amathia verticillata (Montenegro), Ampithoe valida (Italy), Antithamnion amphigeneum (Greece), Clavelina oblonga (Tunisia and Slovenia), Dendostrea cf. folium (Syria), Epinephelus fasciatus (Tunisia), Ganonema farinosum (Montenegro), Macrorhynchia philippina (Tunisia), Marenzelleria neglecta (Romania), Paratapes textilis (Tunisia), and Botrylloides diegensis (Tunisia)