Macrofungi in the secondary succession on the abandoned farmland near the Białowieża old-growth forest

Abstract

The paper deals with the succession of basidiomycete macrofungi on abandoned farmland. The research was carried out in the unique complex of old fields of different age located on the southwest edge of the Białowieża old-growth forest (NE Poland). These lands undergo spontaneous secondary succession leading to formation of a continental fresh pine forest. Regular observations of basidiomata in 16 permanent plots (11 plots of 1000 m2, 5 plots of 400 m2) representing initial, optimal and terminal stage of vegetation development from psammophilous grassland to a pine forest with 100-year-old tree stand were conducted for three years. Soil and vegetation analyses were also carried out as well as quantitative examination of ectomycorrhizae in root samples. The series yielded 300 species of macromycetes (including 6 collective taxa) found in permanent plots plus 18 species outside the plots. The species composition, spatial distribution of sporocarps, and quantitative structure of fungal communities changed along the successional gradient. Increasing diversity of fungi resulted from persistence of species typical of open areas and species associated with younger trees, as well as accumulation of species associated with older trees and more developed stands. Some species typical of younger phases were replaced with species arriving later in the chronosequence. Species usually occurred long before and after attaining maximum abundance and frequency. Species associated with certain periods of vegetation development could be distinguished, as well as species accompanying the phytocoenoses regardless of their developmental stage. Patterns in structural changes of the fungal community, e.g., in number of species, abundance, frequency and production of carpophores, could also be recognised. They were different in ectomycorrhizal and in saprotrophic fungi. The occurrence of the former was influenced mainly by the presence of symbiotic trees and their age, stand structure and soil properties, while occurrence of the latter was affected by microclimatic factors and by diversity of accessible substrates. Changes in fungal communities were consistent with vegetation changes, but were also specific to this group of organisms.