In the medieval period, beavers were widespread throughout Poland. In the 13th century, the number of animals began to decline. After the Second World War, it was assumed that Eurasian beavers were no longer present in Poland. In 1974, the programme “Active protection of European beavers in Poland” was launched. Reintroduction was a very important element of the active protection of beavers. According to an inventory carried out in 1977, there were estimated to be over 1000 individuals. Long-term reintroduction efforts by hunters and scientists have caused beavers to be present throughout Poland. In recent years, the beaver population has increased significantly. This situation has created conflicts between farmers, foresters and beavers. In Poland, the beaver is considered a partly protected species. This manuscript discusses the dynamics of the beaver population in Poland and needed actions for future sustainable management.

One effect of global warming is the increasing risk of drought. The shortage of water in the soil has a direct impact on crop plants. It can therefore be expected that drought stress will negatively affect forests. The aim of this study was to determine the length of the drought in the forests of Poland in 2015. Calculations were carried out using data from 21 meteorological stations for the conditions prevailing in the reference stand, which was determined to be a middle-aged pine stand growing on poor sandy soils classified as Dystric Arenosol. Drought was treated as the state when the soil water available to plants is depleted up to a depth of one meter. Daily changes in soil water storage were measured on the basis of the balance of water inflow-outflow. Climatic water balance was also determined. The calculations of the soil water storage deficit for the conditions of the reference forest ecosystem showed that in 2015 drought soil occurred in almost all of the forests of Poland. Wielkopolska was affected by the earliest-starting and longest-lasting drought. To a lesser extent, however, it extended throughout all of central Poland, from the west to the eastern border of the country. This is where one could expect to see the negative effects of the lack of water available to trees, which can be manifested as a smaller increase in growth, a decrease in health status, and – in particularly unfavorable conditions – dying trees. The climatic water balance showed that the annual water deficit in Wielkopolska exceeded 100 mm.

The Eurasian beaver is currently found in at least 32 European countries, with many of these populations being established in the 1960s. In most European countries, the beaver is under protection, however, when the population is strong, the beaver becomes a game species. In Poland, the beaver is partially protected despite the species having a strong population. In this study we aimed to compare the development trends of Eurasian beaver populations in two management regimes, in Poland (protected) and Belarus (hunted), between 2004 and 2019. We compared beaver population trends in both countries, and analyzed the factors that could impact population growth. In Poland, during this period the population increased 3.5 times, while in Belarus it was only 20%. Distinct differences in the rate of population numbers increase were also observed between regions in Poland, but a stable, slight increase similar in all regions in Belarus. Our study did not show that precipitation or the density of this species influenced the rate of population development in Poland. During this period, hunting and wolf density significantly and negatively impacted beaver population growth in Belarus, but in the long-term analysis, hunting had a lower impact on beaver population growth. We concluded that we can expect a further increase in this population in Poland. Long-term hunting at a level of 13,7% (based on the analysis of population dynamics and hunting bags for Belarus) of the annual population seems to be a safe value for the beaver population. Nevertheless more detailed analysis should be carried out in the face of the large differences between regions.

Management for sustainable river valleys requires balancing their natural values against the need for agricultural and recreational development on surrounding lands. The Southern Całowanie Peatland near the city of Warsaw sits on a sandy terrace and has well preserved Carex and Molinia stands existing in part of the area, especially where water tables are less than 1.5 m below the surface. The existing drainage network in this southern part has been poorly maintained and could be reestablished to help raise water levels for restoration of the peatland. Modflow was used to look at influence of drainage channel water levels on the overall water table height in the area. By raising water levels in the drainage system by 0.5 m it was found that 29% of the area would become suitable for increasing Carex and Molinia communities.

Groundwater is the primary water source for ecosystems, and so changes in groundwater levels, if directional and constant, can cause changes in vegetation and habitat characters. In Białowieża National Park, a significant decline in the water table was observed at the beginning of the 20th century. The question therefore arose as to whether the changes that occurred at that time were permanent. A second question was whether the negative trend would continue so clearly in the following years. The study is based on measurements from 1985 to 2005 and 2022 to 2023 taken in the same monitoring wells. Complete data were collected from 21 monitoring wells. An analysis of groundwater levels between 1985 and 2005 showed an average decline of 0.08 m/10 years in swamp habitats, 0.11 m/10 years in moist habitats, and 0.21 m/10 years in fresh habitats. The measurements in 2022 and 2023 showed that the trend of falling water levels had slowed down in almost the entire study area, with water levels in recent years being similar to those at the beginning of the century. This was also confirmed by comparing years with similar precipitation: 2022 with 1986, and 2002, 2004, and 2023 with 1999. This was due to the higher precipitation after 2005. In the period of 2006–2023, precipitation in the hydrological years was on average 60 mm higher than in the period of 1985–2005. Despite the clear trend toward rising air temperatures, the higher precipitation compensated for the higher evapotranspiration. However, one area showed a systematic decrease in water levels. This occurred at the watershed of the two largest rivers in the Białowieża Forest. The findings indicate that watershed areas are most vulnerable to lowering the groundwater level due to climatic warming.