This paper presents the results of the first short-term inventory of fungi species occurring in the Biebrza National Park, one of the biggest and best preserved protected areas of Poland. The paper is focused on a survey of microfungi. Fungi were collected in early autumn 2012, within the framework of a scientific project by the Polish Mycological Society. The results are published in two parts containing micro- and macromycetes, respectively. An annotated list of 188 identified taxa covers true fungi including 33 zygomycetes, 130 ascomycetes (including anamorphs) and 22 basidiomycetes, as well as two chromistan and one protozoan fungal analogues. The identified fungi taxa, inhabiting diverse ecological niches, represent a wide range of trophic groups including saprotrophs, biotrofic and necrotrophic parasites of plants, pathogens of arthropods, fungicolous fungi and species isolated from soil and organic matter. From 188 annotated taxa, 89% (167 species) have not been recorded in the Biebrza National Park until now and four species are newly reported for Poland (<em>Alternaria nobilis, Clonostachys solani, Mariannaea elegans, Metasphaeria cumana</em>). Data on the species richness and taxonomic diversity of the identified fungi are briefly commented in terms of micromycetes role in managing nature conservation.

The study is part of hydromycological investigations of man-affected water bodies in Olsztyn. Our results show that yeast-like fungi are permanent components in three selected lakes (lakes Tursko, Długie and Skanda). Their abundance and species composition depend on the trophic state of each lake.

Ecological information concerning 292 fungal taxa is reported as a result of two surverys in the Biebrza National Park. Most data presented come from the 5-day all-fungi inventory of the Polish Mycological Society in 2013, and 47 species were recorded during studies in the Biele Suchowolskie fen in 2008/2009. In total, 27 species of zygomycetes, 232 ascomycetes (including anamorphs) and 27 basidiomycetes (mainly Pucciniales). Additionaly some representatives of fungi-like organisms from Stramenopiles (4 species) and Dictyostelia (2) were identified. Fungal groups included were the same as in the previous survey in 2012: 190 taxa associated with plants, 15 with animals, 8 with fungi and 71 isolated from soil, plant debris and animal excrements. The most numerous were anamorphic ascomycetes (159 species). Nineteen species have not been previously known from Poland and 31 species are rare (1–3 localities). For the Biebrza National Park 197 species (67.5%) are new.

The paper presents mycological studies conducted jointly with ornithologists on the epidemiology of mycoses and the taxonomic diversity and prevalence of fungi that colonise the selected onthocenoses in healthy, wild migratory birds. Aquatic ecosystem populations of healthy birds include a percentage of carriers of potential zoo-and anthropopathogens, and this study's purpose was to determine the percentage. The studies were performed on swabs sampled in vivo (during spring and autumn migrations) from the beak and cloaca of nine species of Charadriiformes in two age categories. Macro-and microcultures of fungi were prepared according to the standards for diagnostic mycological laboratories. From the 450 birds examined, fungi were isolated from 130 (26.5%) individuals. The sampling yielded 272 yeast isolates: 170 (62.5%) from the beak and 102 (37.5%) from the cloaca. The isolates represented 23 species, among which C. albicans, C. neoformans, and R. rubra were predominant. In both onthocenoses in young and adult birds, more fungi were recorded in autumn than in spring. As many as 15 species are included in the biosafety level classification, of which seven are categorised as category 2 and one as category 3.

Differentiated responses of Erysiphe alphitoides and E. hypophylla in urban conditions are described. The influence of transport pollution on the morphology of the mycelium, chasmotecium development and individual stages of the developmental cycle is discussed.