Niche Vs. Dispersal Limitation: What Drives Saprotrophic Fungal Community Structure?.

Much of the world’s terrestrial ecosystems depend upon the breakdown of plant tissue for the cycling of nutrients, which is mainly driven by diverse communities of saprotrophic fungi. These fungal communities utilize a complex suite of enzymes to perform these roles. Due to their important functions in the environment, understanding the factors that influence fungal diversity is paramount in our changing world. This study was performed to gain a better understanding of how the environment influences saprotrophic fungal communities in temperate ecosystems.

Nine sites, chosen from three ecosystem types, were selected for study in Manistee National Forest, Michigan. These ecosystems were differentiated based upon dominant over story tree cover. Leaves were sampled from each site in overlapping spatial networks to understand the impact of close proximity on community structure and functional traits (enzyme activity). Taxa were analyzed by using Terminal Restriction Fragment length Polymorphism (T-RFLP), a molecular fingerprinting method. Functional traits were analyzed via quantitative polymerase chain reaction (qPCR) and direct quantification of enzyme activity via MUB-Linked substrates. Leaf litter quality was characterized via chemical extraction of polar, nonpolar and nonacid hydrolysable compounds. Data collected in this study shows that neutral processes (dispersal limitation) explain more of the microbial community composition variability than do the niche processes (leaf type and biochemistry). On the other hand, community functional traits are much better explained by the environment of the organism. Future work will analyze other environmental factors including leaf moisture and depth.