Białowieża National Park

ABSTRACT The highly pathogenic avian influenza virus (HPAIV) A(H5N1) has caused the most extensive and severe epizootic event affecting both poultry and wild birds globally. This study investigated the impact of HPAIV on the breeding population of the Black-headed Gull Chroicocephalus ridibundus, the most abundant gull species in Poland. During the 2023 outbreak, this species was reported as the most frequently infected in the country. A higher-than-natural adult mortality rate (greater than 1.5% of the breeding individuals) was observed in 114 surveyed colonies across all regions of Poland. Laboratory tests confirmed the presence of HPAIV in all 17 colonies sampled, with average adult mortality estimated at 26.1%, and ranging from 1.7% to 77.8%. The estimated mortality rate across all surveyed colonies was 22.2%. Extrapolations across the entire Polish breeding population (at least 115,000 pairs according to the national census) indicated that approximately 51,000 adult Black-headed Gulls might have perished due to HPAIV in 2023. The number of adults found dead was positively correlated with colony size (r = 0.733, P < 0.001). The deaths were associated with a single HPAIV genotype (BB) across all confirmed cases. Understanding the spread and severity of HPAIV in colonially breeding waterbirds, such as gulls, is essential for assessing the full extent of the threats this virus poses to wild bird populations.

In winter 2021/2022, a wolf population in the primeval Białowieża Forest in Poland was struck by an outbreak of severe mange caused by mixed infestations of Sarcoptes and Demodex mites. We present an epidemiological analysis of this mange which caused significant morbidity and mortality. Ten sites known for wolf activity were monitored by camera trapping. A diagnostic necropsy and testing of a young wolf was performed to determine the causes of death. Five young wolves with severe alopecia of the entire body and some other individuals with minor to medium mange lesions were identified by the camera surveillance. The necropsy of the carcass revealed emaciation, dehydration and anaemia with starvation as the cause of death, likely attributable to severe infestation with Sarcoptes scabiei and Demodex sp. mites. Rabies and infections with Borreliella sp., Anaplasma sp., Ehrlichia sp., Francisella tularensis, Babesia sp. and tick-borne encephalitis virus were excluded by specific tests. The described analysis is the first documented co-infestation of this kind in wolves. The outbreak coincided with very mild winter conditions with a high average minimum temperature, which may have favoured mite survival outside the host, and light snowfall, which may have influenced the wolves' ability to hunt. Other potential drivers of the outbreak could be the large proportion of wetland terrain, increasing number of wolves in the area and anthropogenic pressure on their habitats including the migration crisis at the Polish-Belarusian border and the increased presence of military and border forces, even despite the relief from the anthropogenic pressure from tourism due to the COVID-19 lockdown.

This study assessed the operational efficiency of a hybrid constructed wetland in its first year of use. The test facility was put into operation in September 2022 and has since been utilized to treat 0.4 m3/d of wastewater discharged from a forester's lodge located in the Polesie National Park in Poland. The treatment plant consists of a two-chamber primary settling tank integrated with a pumping station, and a system of two beds – a vertical flow (VF) reed bed and a horizontal flow (HF) willow bed. During the research period (October 2022 to December 2023), 14 test runs were performed during which 56 sewage samples were collected for physico-chemical and microbiological assays. The results of these tests were used to determine the pollutant removal efficiency of the CW. The composition of treated wastewater was compared against the current Polish requirements for this type of facilities. The study also included measurements of influent and effluent volumes and the amount of rainwater entering the treatment plant. It was shown that precipitation in each month of the study accounted for between 6–34% of influent volume. The volume of wastewater discharged from the treatment plant during the study period was 11% lower than the volume of incoming wastewater combined with rainwater. It was found that the CW removed an average of over 90% of total suspended solids, BOD5, COD, Escherichia coli bacteria and fecal enterococci from wastewater. Slightly lower removal efficiencies were achieved in the case of total nitrogen and total phosphorus (60–74%). Already during the start-up period, the composition of treated wastewater discharged from the CW met the requirements set out in the current Polish legal regulations. The present study shows that hybrid VF-HF constructed wetlands can be recommended for use in protected areas for wastewater treatment and protection of water against eutrophication.

Global change has accelerated local species extinctions and colonizations, often resulting in losses and gains of evolutionary lineages with unique features. Do these losses and gains occur randomly across the phylogeny? We quantified: temporal changes in plant phylogenetic diversity (PD); and the phylogenetic relatedness (PR) of lost and gained species in 2672 semi-permanent vegetation plots in European temperate forest understories resurveyed over an average period of 40 yr. Controlling for differences in species richness, PD increased slightly over time and across plots. Moreover, lost species within plots exhibited a higher degree of PR than gained species. This implies that gained species originated from a more diverse set of evolutionary lineages than lost species. Certain lineages also lost and gained more species than expected by chance, with Ericaceae, Fabaceae, and Orchidaceae experiencing losses and Amaranthaceae, Cyperaceae, and Rosaceae showing gains. Species losses and gains displayed no significant phylogenetic signal in response to changes in macroclimatic conditions and nitrogen deposition. As anthropogenic global change intensifies, temperate forest understories experience losses and gains in specific phylogenetic branches and ecological strategies, while the overall mean PD remains relatively stable.

Forests are a substantial terrestrial carbon sink, but anthropogenic changes in land use and climate have considerably reduced the scale of this system1. Remote-sensing estimates to quantify carbon losses from global forests2–5 are characterized by considerable uncertainty and we lack a comprehensive ground-sourced evaluation to benchmark these estimates. Here we combine several ground-sourced6 and satellite-derived approaches2,7,8 to evaluate the scale of the global forest carbon potential outside agricultural and urban lands. Despite regional variation, the predictions demonstrated remarkable consistency at a global scale, with only a 12% difference between the ground-sourced and satellite-derived estimates. At present, global forest carbon storage is markedly under the natural potential, with a total deficit of 226 Gt (model range = 151–363 Gt) in areas with low human footprint. Most (61%, 139 Gt C) of this potential is in areas with existing forests, in which ecosystem protection can allow forests to recover to maturity. The remaining 39% (87 Gt C) of potential lies in regions in which forests have been removed or fragmented. Although forests cannot be a substitute for emissions reductions, our results support the idea2,3,9 that the conservation, restoration and sustainable management of diverse forests offer valuable contributions to meeting global climate and biodiversity targets.

Mutualistic interactions are by definition beneficial for each contributing partner. However, it is insufficiently understood how mutualistic interactions influence partners throughout their lives. Here, we used animal species-explicit, microhabitat-structured integral projection models to quantify the effect of seed dispersal by 20 animal species on the full life cycle of the tree Frangula alnus in Białowieża Forest, Eastern Poland. Our analysis showed that animal seed dispersal increased population growth by 2.5%. The effectiveness of animals as seed dispersers was strongly related to the interaction frequency but not the quality of seed dispersal. Consequently, the projected population decline due to simulated species extinction was driven by the loss of common rather than rare mutualist species. Our results support the notion that frequently interacting mutualists contribute most to the persistence of the populations of their partners, underscoring the role of common species for ecosystem functioning and nature conservation.

Drivers of bird niche separation in temperate primeval forests have not yet been determined, due to the low number of intact forest sites. Here, we analyzed the general patterns of niche usage on trees by birds’ assemblages. We tested how tree species affect the sharing of space in an assemblage of birds and their level of specialization. We conducted our study in the Białowieża primeval forest (NE Poland). During two breeding seasons, we observed bird positions on trees, divided into three vertical and six horizontal zones in 768 observation points. Based on the interaction networks framework we calculated the Kullback-Leibler distance d′ as a metric of species specialization and the resource range RR index, which estimates the species’ specificity based on the fraction of space utilized with a non-zero performance. The d′ index was the highest in the lower understory for all parts of the tree on the basis of the position from the trunk. The RR index was the highest in the lower understory for all parts based on the position from the trunk. Regarding the tree species, the lowest d′ index was observed in all tree species together, and hornbeam, whereas the highest in oak. At the tree species level, the RR index was the lowest for hornbeam. We show tree species importance in forest space sharing in the case of bird assemblages. Hornbeam, alder, and spruce are universal species that were used by birds almost entirely. In contrast, oak, lime, and maple were only partially used. Tree species with less complex structures could shape bird assemblages, as they could offer birds much fewer niches to realize. Therefore, we showed that high specialization and niche separation are drivers of high bird diversity. Consequently maintaining a diverse stand structure is crucial for biodiversity conservation.

The results of bryological research on the Chęciny Hills (southern part of the Świętokrzyskie Mountains) are presented. In the area of Góra Rzepka Mt. and Góra Zamkowa Mt. 124 of bryophytes – 12 of liverworts and 112 of mosses were noted. The occurrence of protected, threatened and mountain species as well as ecological diversity of bryoflora are discussed.

Grassland breeding waders have been steadily declining across Europe. Recent studies indicating a dramatic decline in grassland invertebrates' abundance and biomass, the key food of most grassland wader chicks, suggest a likely driver of the demise of waders. While agricultural intensification is generally inferred as the main cause for arthropod decline there is surprisingly little information on the relationship between land use intensity and total arthropod abundance in grasslands. Here, we explored those relationships across several key wader breeding habitats by surveying ground-active, aerial and soil-dwelling invertebrate communities in five European countries that range from natural undisturbed bogs to intensively managed grasslands. Using maximum vegetation growth and soil moisture content we investigated how they shape the size of the invertebrate community within and across different countries. We found predominantly positive relationships between grassland invertebrate abundance, biomass and body weight with increasing vegetation growth and soil moisture. Maximum vegetation growth was strongly positively related to ground-active invertebrate abundance and biomass and abundance of soil dwelling invertebrates (mainly earthworms). Body weight of aerial invertebrates furthermore increased with increasing maximum vegetation growth. Our results provide little support for the hypothesis that agricultural practices associated with intensification of grassland management result in an abundance decline of invertebrate prey for wader chicks. Conservation practices aiming to enhance wader chick survival require a careful balancing act between maintaining habitat productivity to secure high prey abundance, and keeping productivity low enough to maintain open swards that do not need to be cut before chicks have fledged.