Spatial priorities for freshwater biodiversity conservation in light of catchment protection and connectivity in Europe

Abstract

Freshwater ecosystems host disproportionately high numbers of species relative to their surface area yet are poorly protected globally. We used data on the distribution of 1631 species of aquatic plant, mollusc, odonate and fish in 18,816 river and lake catchments in Europe to establish spatial conservation priorities based on the occurrence of threatened, range-restricted and endemic species using the Marxan systematic conservation planning tool. We found that priorities were highest for rivers and ancient lakes in S Europe, large rivers and lakes in E and N Europe, smaller lakes in NW Europe and karst/limestone areas in the Balkans, S France and central Europe. The a priori inclusion of well-protected catchments resulted in geographically more balanced priorities and better coverage of threatened (critically endangered, endangered and vulnerable) species. The a priori exclusion of well-protected catchments showed that priority areas that need further conservation interventions are in S and E Europe. We developed three ways to evaluate the correspondence between conservation priority and current protection by assessing whether a cathment has more (or less) priority given its protection level relative to all other catchments. Each method found that priority relative to protection was high in S and E Europe and generally low in NW Europe. The inclusion of hydrological connectivity had little influence on these patterns but decreased the coverage of threatened species, indicating a trade-off between connectivity and conservation of threatened species. Our results suggest that catchments in S and E Europe need urgent conservation attention (protected areas, restoration, management, species protection) in the face of imminent threats such as river regulation, dam construction, hydropower development and climate change. Our study presents continental-scale conservation priorities for freshwater ecosystems in ecologically meaningful planning units and will thus be important in freshwater biodiversity conservation policy and practice, and water management in Europe.

Integrating environmental DNA monitoring to inform eel (Anguilla anguilla) status in freshwaters at their easternmost range—A case study in Cyprus

“…Our results are reflective of wider pressures on freshwater catchments in south and east Europe, where conservation action is required due to growing threats from river regulation, dam construction, hydropower and climate change (Szabolcs et al, 2022). Steps to identify eel priority sites, improve connectivity to water supply dams where possible, and consider eel passability in the design for future dams during the construction phase could be of benefit here.…”

Integrating environmental DNA monitoring to inform eel (Anguilla anguilla) status in freshwaters at their easternmost range - A case study in Cyprus

“…Our results are reflective of wider pressures on freshwater catchments in south and east Europe, where conservation action is required due to growing threats from river regulation, dam construction, hydropower and climate change (Szabolcs et al, 2022).…”

Monitoring for Anguillicoloides crassus, Anguillid herpesvirus 1, aquabirnavirus EVE and rhabdovirus EVEX in the European eel population of southern Spain

“…The high infection prevalence and intensity of L3 and L4 gives evidence to the fact that A. crassus has adapted to Andalusian river and lagoon habitats, where there is abundance of intermediate and paratenic hosts, mainly copepods (Dangel et al, 2015), amphibians, small fish (Haenen & Van Banning, 1990), some of them harbouring acanthocephalans as internal parasites (Hohenadler et al, 2018; Weclawski et al, 2013), are an important part of the eel diet. This high biodiversity (Szabolcs et al, 2022), together with the fact that eels are predators of a wide variety of prey (Tesch, 2003), is the reason why A. crassus has been able to adapt to fluvial and lagoon ecosystems of Andalusia.…”

“…The high infection prevalence and intensity of L3 and L4 gives evidence to the fact that A. crassus has adapted to Andalusian river and lagoon habitats, where there is abundance of intermediate and paratenic hosts, mainly copepods (Dangel et al, 2015), amphibians, small fish (Haenen & Van Banning, 1990), some of them harbouring acanthocephalans as internal parasites (Hohenadler et al, 2018;Weclawski et al, 2013), are an important part of the eel diet. This high biodiversity (Szabolcs et al, 2022), together with the fact that eels are predators of a wide variety of prey (Tesch, 2003), is the rea- authors (Costa-Dias et al, 2010;Kirk et al, 2000;Nielsen, 1997), water salinity has not been found to be a determining factor for the prevalence and intensity of infection with A. crassus in the rivers analysed. A. crassus was more prevalent in eels captured in summer and autumn than in other months, which contrasts with many studies not registering any infection seasonality (Kennedy & Fitch, 1990;Möller et al, 1991;Molnár et al, 1994;Thomas & Ollevier, 1992;Würtz et al, 1998).…”