Materiały do brioflory Polski północno-wschodniej. Mchy i wątrobowce rezerwatu „Stara Dębina” (Puszcza Knyszyńska).

The study presents data on the bryoflora of the “Stara Dębina” nature reserve, which is located within the Puszcza Knyszyńska Forest in north-eastern Poland. The study aimed to characterize the bryophytes in the reserve with a particular focus on rare, protected species and indicators of old-growth forests. Field studies were carried out in July 2022. A total of seven liverwort species and 46 moss species, including one variety, were documented. Five of these species had not previously been recorded in the Puszcza Knyszyńska Forest. Eleven of the species are protected, and seven are considered an indicator of old-growth forests. The ecological characteristics of all recorded species were analysed, with particular focus on their microhabitats, including soil, tree bark, and decomposing wood. The results indicate that the bryophyte flora of the reserve is relatively poor and dominated by mesophilous species that are typical of deciduous and mixed forests. The limited occurrence of old-growth indicator species highlights the need to preserve suitable microclimatic conditions within the forest. This study contributes to our knowledge of regional bryophyte diversity and emphasises the importance of conservation efforts in maintaining biodiversity.