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Donja Dubrava
Donja Dubrava

Restored branches near Donja Dubrava, Legrad, and Gola were opened

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Donja Dubrava, March 14, 2024 – Activities for the restoration of Drava River branches within the project “DRAVA LIFE – Integrated River Management” have been completed in the areas of the municipalities Donja Dubrava, Legrad (rkm 238.2-241.4), and Gola (rkm 215-217). With the increase in water levels, the restored branches have become flowing again.

Through the opening and creation of new branches, the removal and adaptation of riverbanks and other water structures, as well as the preservation of floodplains and natural steep riverbanks, key natural features of the Drava River ecosystem, one of the last remaining natural European rivers, are restored. Sediments and barriers were removed from existing branch channel routes, ecological ponds and deep pools were constructed, and gabion barriers and transition ramps were reconstructed at several locations.

“After the restoration works, which began at the end of September 2023, the left bank branch near Donja Dubrava will be 1.56 km long, and the right bank branch will be 1.88 km long,” explained Igor Tošić, the project manager from the Croatian Waters. Both branches, which were overgrown and silted before the restoration works, will relieve pressure on existing water structures downstream, especially during flood events, by opening and diverting new inflow from the main river channel, thus protecting embankments and nearby settlements. This will reduce the need for repairs and construction of regulatory structures along those sections of the Drava, and specifically, with the restoration of the left bank branch in Donja Dubrava, it will increase embankment safety for flood protection.

Foto: Goran Šafarek

Additionally, in the left bank inundation from stations rkm 215+000 to 217+000 in the municipality of Gola, near the village of Novačka, works have been completed to open the first 100 meters of an existing non-flowing branch, approximately 1.3 km long.

Drava is known for its highest biological diversity of fish in Croatia and colonies of river birds.

“The habitats on the Drava include some of the most endangered in Europe, such as floodplain forests, wet meadows, gravel bars and sandy shores, branches, steep banks, dead arms, standing branches, abandoned channels, and meanders. Due to various adverse effects, with climate change leading the way, there are changes in hydrological conditions, often causing degradation and disappearance of these habitats, making them increasingly endangered, with their area reduced,” explained Željka Kolar, director of the Public Institution for the Management of Protected Nature Areas in the Koprivnica-Križevci County.

Sand martins and king fishers

In addition to the positive effects on flood defense and Drava’s hydromorphology, branch restoration activities will significantly contribute to increasing biodiversity. New river habitats will intensify along the banks, and new habitats for spawning, feeding, and resting of fish and amphibians will be created within the branches themselves. Drava is known for its highest biological diversity of fish in Croatia. Out of 70 recorded species, five are endemic to the Danube basin: Danube salmon (Hucho hucho), bleak (Rutilus pigus), monkey goby (Gymnocephalus baloni), racer goby (Gymnocephalus schraetser), and streber (Zingel streber)). Out of 70 recorded species, 38 are included in the Red Book of Freshwater Fish of Croatia. Positive effects will also extend to birds nesting on gravel and sandy bars and steep banks, such as the sand martin (Riparia riparia) and the kingfisher (Alcedo atthis).

After the recently opened new branch near Gabajeva Grede and the completion of works in the municipalities of Donja Dubrava, Legrad, and Gola, preparatory work for the branch near the Botovo bridge will continue until the end of March, followed by a break until September to prevent disturbance to river birds, such as sand martins (Riparia riparia), European bee-eaters (Merops apiaster), and kingfishers (Alcedo atthis) during the breeding season.

Intensive educational activities will be carried out during these months. Besides the restoration of the Drava River ecosystem, education on nature protection and Natura 2000 areas in local communities is an important part of the DRAVA LIFE project to increase awareness of the importance of natural and preserved rivers for humans and living beings dependent on them and to prevent human disturbance of birds during the breeding season through recreational activities such as fishing, paddling, and swimming.

In September, restoration works on the Drava will continue at the remaining planned locations in Varaždin and Virovitica-Podravina counties.

 

WWF Adria
German tamarisk

Conservation of German tamarisk

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At the end of April, we sent several plants of German tamarisks to the Botanical Garden in Klagenfurt so they could further develop. We hope we will be able to plant them one day in the natural habitats on the Drava River in Croatia, together with new plants.

Botanical Garden, Klagenfurt

Also, to determine the actual origin of German tamarisks that can be found near the Drava River, with the help of our colleague Dragica Purger, we extracted genetic material of German tamarisk from the gravel pit and drainage channel near HPP Dubrava. We can’t wait for the results and to finally have scientific evidence about the origin of the plants.

 

And the first batch of the dwarf cattail is ready! I prve sadnice su u zemlji! © A.Kuzmanić

World Water Day Marked by the Reintroduction of Dwarf Cattail on the Drava River

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LEGRAD – This year’s reintroduction of the dwarf cattail (Typha minima) was held on World Water Day (March 22nd) on several locations along the Drava River. Our expert associate Dragica Purger, PhD, mentioned that the Drava still displays characteristics of a natural, unregulated river.

However, Purger warned that human activity on the river, primarily the construction of hydroelectric power plants, excessive gravel and sand removal, and the construction of regulatory infrastructure, has resulted in major changes in hydromorphological dynamic processes and the ecological condition of the Drava River.

Purger notes that important indicators of negative changes include the disappearance of specific river habitats, gravel and sand banks, as well as the disappearance of key species that depend on these habitats. One of them is the dwarf cattail (Typha minima), which disappeared from the Croatian part of the Drava river in the last three decades. “The reintroduction of dwarf cattail in its natural habitat on the Drava River, implemented within the scope of the DRAVA LIFE project, has a practical and symbolic significance,” Purger said.

©WWF

©WWF

 

 

 

 

 

 

 

 

Dwarf cattail disappeared from this area more than 20 years ago. To be more precise, it was last recorded on gravel bars near Varaždin in 1994. Both the German tamarisk (Myricaria germanica) and the dwarf cattail (Typha minima) are pioneer species that grow on habitats such as sandbanks and river banks in freshwater ecosystems.

“Given that last year’s reintroduction of dwarf cattail was not completely successful due to extremely high water levels, we decided to reintroduce this extinct river plant once again, this time under the guidance of our expert associate Dragica Purger, PhD. We hope that we will have more luck this year and that the plants will grow well”, explained Branka Španiček from WWF Adria. Španiček added that the ultimate success of reintroduction and repopulation can only be ascertained once the seedlings are fully adapted to the new habitat and once they begin to reproduce.

©WWF

©WWF

 

 

 

 

 

 

 

“Successful reintroduction of this plant species will increase the biodiversity and improve the ecological function of river ecosystems, although the permanent establishment of these populations will depend on the implementation of river revitalization measures. It will also be an indicator of improving river conditions and increasing natural value of the Drava River”, concluded Purger. This year’s reintroduction wouldn’t be possible without help of DRAVA LIFE partners and associates from the Drava Federation (Hungary).

Reintrodukcija riječnih biljaka uz Dravu/Reintroduction of riverine plants within the Drava Life project
Reintrodukcija riječnih biljaka uz Dravu/Reintroduction of riverine plants within the Drava Life project

First reintroduction and repopulation of riverine plants in Croatia

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Legrad, Croatia – On Friday March 30, 2018, WWF has implemented the first reintroduction of two extinct riverine plants in Croatia on 3 sites along the Drava River in Koprivnica-Križevci County. This activity was done within the DRAVA LIFE project, funded through the LIFE program of the European Union.

The reintroduction is a process of returning the plant species to the area in nature where those species disappeared, but the conditions for their survival are still remaining. Both the german tamarisk (Myricaria germanica) and the dwarf cattail (Typha minima) are pioneer species that grow on new habitats such as sandbanks and river banks in freshwater ecosystems. Both plants` could be found on this kind of habitats along the Drava river in Croatia until the recent past, but today they are almost extinct from the area due to river regulation activities from the past.

reintrodukcija_kebraa_na_rijeci_dravi_2 Repopulation of German Tamarisk

 

 

 

 

 

 

 

“Appropriate habitats for these two species on the Drava river are still here, but these species have disappeared from them due to various anthropogenic influences and changes in the morphodynamics of the river. These species are considered to be indicators of the river that has natural hydromorphological dynamics and a shape of the riverbed that changes. Drava river is still one of them”, said Branka Španiček, DRAVA LIFE project officer in WWF Adria.

The german tamarisk and dwarf cattail are considered to be one of the most important indicators of healthy and natural rivers. Human impacts on rivers (e.g. channelization, construction of hydropower plants as well as gravel and sand extraction) alter vital hydro-morphological processes, reduce river gravel dynamics and affect natural floods, all being essential features for these natural ecosystems to develop and persist. Gravel and sand bars as pioneer habitat types have become very rare in Europe and they are among the most endangered ecosystems. Therefore, they are declared as priority habitats within the European Habitat Directive in the European Union.

The german tamarisk until recently could be found on only two sites at the confluence of the Drava and Mura, on two gravel pits and along the drainage channel near the hydropower plant Donja Dubrava. It is a statutorily protected species in Croatia and listed by the IUCN as critically endangered. Only 26 seedlings found in two gravel pits of German tamarisk were repopulated to 3 previously chosen locations near Legrad in Koprivnica-Križevci county.

Sadnja Patuljastog rogoza

Ušće Mure u Dravu

 

 

 

 

 

 

 

“Unfortunately just few young seedlings with well-developed root system have been found on those locations. Mostly adult plants of German tamarisk were dug out and planted on 3 different locations which are most suitable for their survival. Adult plants are still less susceptible to dryness and mechanical disruption than juvenile plants and therefore can be planted in various microhabitats. This method was chosen because it was verified and proven as the most successful method in the reintroduction of riverine plants in Austria, Germany and Switzerland”, said dr. Dragica Purger, a botanist and expert associate in the DRAVA LIFE project for the plants reintroduction and repopulation activity.

The dwarf cattail is on the European Bern Convention list for the Protection of Wild Species and Natural Habitats. The existence of dwarf cattail in Croatia could not been confirmed, and this species is unfortunately considered to be extinct from the territory of Croatia due to the human activities. Several hundreds of adult plants of dwarf cattail with developed roots system have been reintroducted to sand banks along the Drava river near Legrad as well. The plants were brought from Carinthia in Austria, from the Upper Drava ecosystem. Expert Dr. Gregory Egger has accompanied the removal and safe transport of the plants.

If the action turns out successful, German tamarisks and dwarf cattails will once again become indicators of an intact and healthy free flowing river and their reintroduction aims to directly improve the biodiversity of flora and fauna and the natural values ​​of Drava river’s ecosystem.

The event of reintroduction and repopulation of riverine plants was also supported by Ivan Sabolić, Mayor of Legrad and Marina Mihalec, Deputy Mayor of the Municipality of Đelekovec, who both helped plant a mother plant on an island in the Drava. Partners in the Drava life project from Croatian Waters, WWF, Public Institutions for the Management of Protected Areas of Nature in Koprivnica-Križevci County conducted the reintroduction together, with support from local fishermen and Rafting club Zeus.

German tamarisk/Kebrač Patuljasti rogoz/Dwarf cattail

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