Freshwater crayfish distribution update and maps for Greece: combining literature and citizen-science data

Abstract

-Crayfish are charismatic creatures of high interest to humans, among others playing key roles in freshwater ecosystems. Considering the significance of indigenous crayfish species (ICS) as well as the risks posed by non-indigenous crayfish species (NICS) that may dissemite a crayfish plague pathogen Aphanomyces astaci, astacological research has advanced particularly in Europe. In this context, crayfish distribution patterns are of fundamental importance. Focused on all crayfish established in the Greek wild, we provide an updated distribution and maps, combining extensive review of existing literature as well as newly emerging sources, largely represented by increasingly important citizen-science data. Obtained results demonstrate that ICS, mainly the Astacus astacus and Austropotamobius torrentium, remain relatively well settled in the country. The last ICS, Astacus leptodactylus, was translocated in few places outside its native range, leading to the formation of new flourishing populations and at least in one case it sustains commercial exploitation. Concerning NICS, a single population of Pacifastacus leniusculus is also established in the artificial lake Agra (Region of Central Macedonia) and keeps spreading. Unfortunately, there are only few methods under a very narrow range of conditions making successful eradication of unwanted NICS populations feasible. This option is even more difficult as this population is commercially exploited and traded. Since further potentially problematic NICS are also pet-traded in the country, educating public and communicating highlighted issues are the most effective ways limiting their releases and consecutive establishment in the wild.Keywords: Astacidae / biogeography / indigenous species / invasive species / mapping Résumé -Mise à jour de la distribution des écrevisses d'eau douce et cartes pour la Grèce : combinaison de données de littérature et de données de la science citoyenne. L'écrevisse est une créature charismatique d'un grand intérêt pour les humains, entre autres, qui joue un rôle clé dans les écosystèmes d'eau douce. Compte tenu de l'importance des espèces indigènes d'écrevisses (ICS) et des risques que représentent les espèces non indigènes d'écrevisses (NICS) qui peuvent disséminer un agent pathogène de la peste des écrevisses Aphanomyces astaci, la recherche astacologique a progressé particulièrement en Europe. Dans ce contexte, les schémas de distribution des écrevisses sont d'importance fondamentale. Centré sur toutes les écrevisses établies dans les milieux naturels grecs, nous fournissons une distribution et des cartes mises à jour, combinant une revue approfondie de la littérature existante ainsi que de nouvelles sources émergentes, largement représentées par des données de plus en plus importantes de la science citoyenne. Les résultats obtenus montrent que les ICS, principalement Astacus astacus et Austropotamobius torrentium, restent relativement bien implantés dans le pays. Le dernier ICS, Astacus leptodactylus, a été transféré en quelqu...

Recent changes in distribution pattern of freshwater crayfish in Croatia − threats and perspectives

“…As for A. leptodactylus, the most robust European native species that shows some invasive characteristics (Holdich et al, 2009;Hudina et al, 2016;Perdikaris et al, 2017b), collected data indicated their spreading into new areas previously inhabited by A. astacus , and at the same time their disappearance due to NICS dispersal (this study, Hudina et al, 2013Hudina et al, , 2017Rebrina et al, 2015). Since A. leptodactylus is known to be moderately resistant to the pathogen A. astaci (Kokko et al, 2012;Svoboda et al, 2012), we may expect its further slow-paced disappearance in contact zones with NICS, mainly due to competitive exclusions (Hudina et al, 2016), and further spreading and replacement of other ICS in continental Croatia.…”

Phenology of overland dispersal in the invasive crayfish Faxonius immunis (Hagen) at the Upper Rhine River area

“…Collectively, citizen science studies show the potential to collect extensive data at low costs across large areas (Dickinson et al, 2010). For crayfish distribution, Perdikaris et al (2017) have shown that citizen science data could provide useful data on presence and distribution of species. In our project, we wanted to collect data on the so far badly known phenology of overland dispersal as well as new data on distribution of F. immunis.…”

An assessment of regulation, education practices and socio-economic perceptions of non-native aquatic species in the Balkans

“…Based on the results of this survey, countries with a coastline seem more focused on marine than freshwater environments. Citizen science initiatives on NNS are well developed in marine ecosystems in Greece (Perdikaris et al 2017, Zenetos 2017, Giovos et al 2019 and have begun in Albania (Tanduo et al 2020) and Turkey (Huseyinoglu et al 2021 The definition of NNS of Montenegro is regulated by policy acts and corresponds to the NNS definition stipulated in the policy acts of Croatia. However, in other Balkan countries, as in the EU Member States, there is no consistent definition of NNS (Boon et al 2020).…”