by Marija Smederevac, WP3 Leader (River ecosystems)
In 2024, we had an exciting year focused on the biological aspect of the Danube4All project. We kicked off the year by hosting workshops in schools where we had the opportunity to introduce students and teachers to our project's goals. Through group activities with the children, we helped them understand the importance of restoring river ecosystems. We also created a draft report, marking a key milestone in our work, where we highlighted gaps in current research and the application of knowledge in practice. Alongside these efforts, we worked hard to spread the word about our project in the media, with articles published in two magazines and live TV appearances on two channels, including YouTube. Through our collaboration with NGOs and the Faculty of Architecture, we are also working on protecting the floodplain area of the Danube in Belgrade, our Synergy site.
In 2024, we developed a new database for fish species occurrence, thanks to the data collected by our partners at the national level. We successfully applied a new data cleaning method (specleanr) to 79,477 records from nine countries. Using these cleaned records, we applied a Species Distribution Model (SDM) to predict the occurrence probabilities of 58 fish species, based on 59,612 occurrence records and environmental variables. We produced habitat suitability maps, which were shared at scientific conferences, and we plan to publish most of the fish occurrence data in an open-access journal.
To gather more insights, we developed questionnaires in seven languages, distributing them to over 800 experts and stakeholders from Danube countries. These questionnaires helped us identify issues related to fish biodiversity, monitoring, conservation, and restoration in the Danube River. Reaching 800 experts was a significant step in spreading awareness about our project. We received 140 valid responses, which will be incorporated into our report on the ecological status and biodiversity deficits in the Danube River.
Looking ahead, we are preparing for the transnational biodiversity monitoring scheme (JDS5), scheduled for the summer of 2025. The D4all team is contributing significantly to this effort, which will address the gaps identified through the SDM and questionnaire. We’ve also drafted a document coordinating abiotic and biotic monitoring at our demonstration sites, which has been shared with case study leaders.
We’ve already begun monitoring at our demonstration sites:
Upper Danube (Paradise Island): We’re removing about 800 meters of rip-rap and lowering groyne roots in winter to create a secondary flow channel and natural shoreline behind Paradise Island. Our goal is to increase the abundance of juvenile fish by 50% along the restored banks.
Middle Danube (Tahitótfalu): Here, we’re opening groynes to create a new side channel with higher flow velocity. We aim to increase fish biomass in the modified groyne sections.
Lower Danube (Danube Delta): In the Razelm Sinoe Lagoon, we’re reconnecting the river, lagoon, and sea to improve hydrological connectivity, water renewal, biodiversity, and socio-economic conditions. Our goal is to increase fish species richness in the reconnected lagoon.
Through these activities, we are steadily progressing toward a healthier and more connected Danube River.