A. Kruk

Applicability of the abundance/biomass comparison method for detecting human impacts on fish populations in the Pilica River, Poland

In the Pilica River, a tributary of the Vistula, the abundance/biomass comparison method was employed for assessing the impact of stresses on fish populations. Generally, the method proved a useful tool for estimating disturbances in fish communities caused by point source sewage inputs and all impacts of a dam. A high correlation was recorded between the ABC index and Simpson and Shannon indices, which also negatively respond to the investigated stresses.

Factors shaping communities of pyrophilous macrofungi in microhabitats destroyed by illegal campfires

Pyrophilous macrofungi (PM) are a narrowly specialised group appearing exclusively in plant communities recently destroyed by fire. Their significance has hitherto been studied only for vegetation destroyed over large areas, while in small areas of fire, i.e., microhabitats they are viewed as independent components of the community linked only to the substratum. In the present work, the following hypotheses were tested: (1) species structures of PM in microhabitats depend on the type of plant community, (2) PM form communities on a small scale which are similar in structure and function to analogous large scale communities. We studied 20 surfaces destroyed by illegal campfires in four natural plant communities: oak-hornbeam forest Tilio-Carpinetum (TC), lowland acidophilus beech forest Luzulo pilosae-Fagetum (LF), suboceanic pine forest Leucobryo-Pinetum (LP), and an initial-phase xerothermic grassland community on a transitional habitat (MH). TC and LF habitats were conspicuously more favourable for PM than LP and MH. In TC and LF fire leads to significant loss of mycorrhizae in the upper layer of leaf litter. This provides a development opportunity for ectomycorrhizal PM species which, having little competition, substitute for the destroyed fragments of mycorrhizal networks. In LP and MH fire over a small surface does not destroy more deeply located mycorrhizal associations. Another important factor for PM influencing the quality of environment is the fertility of soil: highest in TC, intermediate in LF and lowest in LP and MH. The results casts doubt on the concept that PM are only synusia linked to the substratum (burnt wood). PM growing in microhabitats constitute an important group of organisms which facilitate rapid regeneration of plant community fragments destroyed by fire.