Ectomycorrhizal fungal succession in mixed temperate forests.
Ectomycorrhizal (ECM) fungal communities of Douglas-fir (Pseudotsuga menziesii) and paper birch (Betula papyrifera) were studied along a chronosequence of forest development after stand-replacing disturbance. Previous studies of ECM succession did not use molecular techniques for fungal identification or lacked replication, and none examined different host species. Four age classes of mixed forests were sampled: 5-, 26-, 65-, and 100-yr-old, including wildfire-origin stands from all four classes and stands of clearcut origin from the youngest two classes. Morphotyping and DNA sequences were used to identify fungi on ECM root tips. ECM fungal diversities were lower in 5-yr-old than in older stands on Douglas-fir, but were similar among age classes on paper birch. Host-specific fungi dominated in 5-yr-old stands, but host generalists were dominant in the oldest two age classes. ECM fungal community compositions were similar in 65- and 100-yr-old stands but differed among all other pairs of age classes. Within the age range studied, site-level ECM fungal diversity reached a plateau by the 26-yr-old age class, while community composition stabilized by the 65-yr-old class. Simple categories such as 'early stage', 'multi stage', and 'late stage' were insufficient to describe fungal species' successional patterns. Rather, ECM fungal succession may be best described in the context of stand development.
Twieg
Brendan D
BD
Department of Biology and Physical Geography, University of British Columbia Okanagan, 3333 University Way, Kelowna, British Columbia V1V 1V7 Canada.
Durall
Daniel M
DM
Department of Biology and Physical Geography, University of British Columbia Okanagan, 3333 University Way, Kelowna, British Columbia V1V 1V7 Canada.
Simard
Suzanne W
SW
Department of Forest Sciences, University of British Columbia Vancouver, 2424 Main Mall, Vancouver, British Columbia V6T 1Z4 Canada.
D029662:Betula / Q000382:microbiology*; D044822:Biodiversity; D038821:Mycorrhizae / Q000145:classification / Q000235:genetics / Q000254:growth & development*; D018517:Plant Roots / Q000382:microbiology; D028224:Pseudotsuga / Q000382:microbiology*; D036226:Seedlings / Q000382:microbiology; D013045:Species Specificity