Beavers – nature’s ecosystem engineers – and interspecies cohabitation

19.06.2021 (Sat)
Leading: Agata Kowalewska and Roman Głodowski

On the hot morning of June 19, 2021, a group of 20 people gathered on the banks of the Warta, near Queen Jadwiga Bridge, to learn more about Poznań beavers during a canoeing workshop. The date was not a coincidence. It was supposed to be the last Saturday for the next weeks, or perhaps months, when it would be possible to complete the planned excursion in canoes, since the water levels were not too high. In the past, the so-called “St. John’s flood” – “a small flood” – usually struck every year around St. John’s Day in Poland, raising the water level. However, climate change had disturbed this regular cycle and we preferred not to take any risks (it turned out the following week that “St. John’s flood” struck this year, but the rainfall did not last for long). The aim of the workshop was twofold: in the first place, following the instructions of one of the organizers and experts, Roman Głodowski from the “Nasz Bóbr” [Our Beaver] Association, we looked for traces of beavers, learning about their behavior and biology as well as the history of the beaver reintroduction program in Poland. Then, back on the mainland, we talked about beavers and the possibility of living together, multispecies cohabitation, urban planning, and rebuilding cities.

Our group consisted of both experienced canoeists and novices. With the help of our instructor, we quickly mastered basic canoe strokes and set off down the river. It was a very hot day. Covered in sunscreen, wearing hats, and equipped with water bottles, we were carried by the current and watched the city from the river, discovering it from a completely new perspective. Already during our first stop, near the Old Port, it became clear that the water level was low. As we learned from our instructor, the exposed structural elements of the fortifications indicated that the water level should have been almost one meter higher. Poznań, and Poland in general, has been suffering from water shortages for years, mainly as a result of low rainfall and very poor water retention to which man-made modifications of riverbanks and a network of drainage channels contribute. Additionally, in cities, impermeable concrete and asphalt surfaces do not allow water to penetrate through. Hence, among others, our interest in beavers, which build dams and lodges and thus significantly improve local water retention, slow down erosion, and enrich soils, and, as a result, increase ecosystem biodiversity.

In 1950, only one wild beaver family was reported to live in Poland. It is estimated that there had been no beavers in Wielkopolska for 600 years. Thanks to the spectacular success of the reintroduction program, tens of thousands of beavers now live across Poland, and they are beginning to play an important role in mitigating the effects of anthropogenic environmental and climate changes. At the same time, they are undeniably charismatic. However, they are considered pests by many people, including government officials. It is said that there are too many beavers, which (sic!) poses a threat to the natural environment. For this reason, even though beavers are under partial protection, they might be exempt from it in some cases, e.g., when they are accused of flooding a field or gnawing on trees in an orchard or a garden. In such situations, dams and lodges are destroyed, and beavers, especially the young, often die. Conflicts between beavers and humans also take place in Poznań – beavers gnawed on the oaks in Rogalin and flooded the Wola Hippodrome. We talked about strategies for mitigating such conflicts in the areas where humans and beavers live together during the workshops.

During our trip, we entered a canal that was covered with lush greenery, which cut into Ostrów Tumski from the west. With the water level so low, our oars scraped the riverbed in some places. We stopped for a moment, hiding in the shade of a large tree, to talk about burrows. Entrances to burrows must always be under water – beavers know in advance what water level fluctuations will be like and can also adjust their mating season accordingly, anticipating a warm spring. They know in autumn whether the winter will be harsh and, depending on this, they gather winter food supply cache. We looked for beavers, but on the canal, just like on the entire section of the Warta we had passed through, we did not find any recent traces of beavers. We found them only on the Cybina, which we entered from the north. According to our beaver expert, Roman Głodowski, there were not many traces of beavers at all, less than we had anticipated. However, we saw some towards the end of our trip, so the search was successful, albeit not spectacularly successful. Then, we turned back and finished our trip in the Szeląg Garden. Sipping on cold drinks, we talked for a long time about beavers and interspecies cohabitation, which would be able to survive the increasingly hot and dry years to come.