Terrestrial Macrofungi of Illinois Old-Growth Prairie Groves

Article excerpt

ABSTRACT.-Macrofungi from two old-growth prairie grove remnants in the Midwestern United States (Brownfield and Trelease Woods, Champaign Co., IL ) were surveyed over two summer and fall fruiting periods. Communities of Ascomycetes, Basidiomycetes and Myxomycetes were sampled and compared using multivariate statistical analyses. Standard estimations of species richness were calculated for comparison with other studies of fungal diversity. Environmental factors (rainfall, humidity, air temperature and soil temperature at 10 cm depth) as well as leaf litter composition, and woody plant communities were surveyed to assess their impact on fungal communities. Fungal community structure was found to differ significantly both between and within Brownfield and Trelease Woods. Communities of terrestrial macrofungi were determined to be strongly influenced by seasonality, with soil temperature at 10 cm depth showing the strongest correlation to changes in community composition. Brownfield and Trelease Woods, formerly part of a contiguous prairie grove with likely a single fungal community, are shown to have developed significantly different fungal communities over a period of separation of more than 120 y.

INTRODUCTION

Fungi are integral components of terrestrial ecosystem function, responsible for much of the decomposition and recycling of nutrients. Fungi further influence terrestrial ecosystems through mycorrhizal and endophytic associations with vascular plants and by serving as parasites, food sources and natural biological controls (Dix and Webster, 1995; Wicklow and Carroll, 1992).

Hawksworth (1991, 2001) conservatively estimated the number of fungi existing in nature to be greater than 1.5 million species, of which fewer than 10% have been described. While interest in fungal biodiversity has grown in recent years, much of this interest has been centered on estimating the total number of fungal species in the world, rather than on understanding fungal diversity on a local scale (Schmit et al., 1999). In the northern hemisphere, stuthes of macrofungal diversity and species richness have been conducted in bodi Europe (Straatsma et al., 2001; Hering, 1966; Richardson, 1970; Ohenoja, 1984) and the United States (Bills et ai., 1986; Brunner and Pettini, 1992; Palmer et al, 1994; Schmit et al., 1999) ; however, the paucity of stuthes is widely recognized (Hawkswordi, 2001; Straatsma et al, 2001).

Owing to the current paucity of fungal diversity stuthes in North America and elsewhere Hawkswordi (2001) argues for increased sampling of fungal diversity at local levels and the establishment of reference communities. Accessible old-growdi forests with protected status are excellent choices for the establishment of fungal biodiversity reference communities. Such reference communities can be compared with other sites and for stuthes of community and ecosystem changes in response to local, regional and global impacts.

Fungi are highly integrated into the old-growth forest environment, playing key roles in food chains (Komonen et al, 2000), and nutrient cycling (Lindahl et al., 2002). Furthermore, fungi play an important role in the balance of the global carbon cycle and are the primary group driving CO2 release in old-growth forests (Rygiewicz and Andersen, 1994).

The purpose of this study was: (1) to provide initial characterization of fungal biodiversity at both Brownfield and Trelease Woods, including estimates of taxon richness; (2) to determine if fungal assemblages present both within and between Brownfield and Trelease Woods are significandy different; (3) to determine which taxa of macrofungi are most informative in characterizing macrofungal assemblages at bodi sites; (4) to evaluate the effects of seasonality on the fungal communities; (5) to determine which site-specific biotic factors correspond most strongly with the fungal assemblages at both sites; and (6) to compare the fungal communities at Brownfield and Trelease woods to other known stuthes of fungal diversity. …