Fungal community structure in some alpine soils

Abstract

The community structure and interactions among the soil microfungi of three alpine sites were investigated using a factor analytical method. The sites were distributed along an elevation gradient, and the diversity and evenness of allotment of species were inversely related to altitude. Clusters of species having similar distributions were defined from factor analyses performed separately for each site. Within each site, differences among the soil horizons were primarily responsible for variation in the fungal community, and species groups were differentiated by their patterns of colonization of the soil profile. Changes in the mycoflora with depth were continuous, although the magnitude of these changes was greater near the surface of the soil. Seasonal changes also were most apparent in the surface horizons.In a grassland site at 1900 m, a species group dominated by Penicillium janthinellum was largely restricted to the surface horizons of the soil, and three other species groups were affected by seasonal changes in the environment. In an alpine meadow site (2530 m), the Penicillium steckii and Cylindrocarpon destructans groups occurred in the surface horizons, with the first group predominant in the spring and the second in the summer and fall. At a summit ridge site (2840 m), all taxa except the sterile fungi were essentially restricted to the surface horizons. Species groups dominated by sterile-dark fungi were predominant in the bottom horizons at all three sites.The most frequently occurring species usually had large communalities indicating a high degree of association with the other species, and probably reflecting their influence over the suitability of the environment for exploitation by other species. The communality structure also indicated a decrease in species interactions with increasing depth of soil.