1999: 8 1837-1850
Community structure of ectomycorrhizal fungi in a Pinus
muricata forest: minimal overlap between the mature
forest and resistant propagule communities
D. Lee Taylor1
and Thomas D. Bruns2
Department of Ecology, Evolution and Marine Biology,
University of California, Santa Barbara, CA 93106, USA.
Correspondence: Dr D. Lee Taylor. Fax: +01-805-893-4724;
Department of Plant and Microbial Biology, 321 Koshland Hall,
University of California, Berkeley, California, 94720, USA
We have investigated colonization strategies by comparing the
abundance and frequency of ectomycorrhizal fungal species on
roots in a mature Pinus muricata forest with those
present as resistant propagules colonizing potted seedlings
grown in the same soil samples. Thirty-seven fungal species
were distinguished by internal transcribed spacer (ITS)
restriction fragment length polymorphisms (RFLPs); most were
identified to species level by sporocarp RFLP matches or to
genus/family level by using sequence databases for the
mitochondrial and nuclear large-subunit rRNA genes. The
below-ground fungal community found in the mature forest
contrasted markedly with the resistant propagule community,
as only four species were found in both communities. The
dominant species in the mature forest were members of the
Russulaceae, Thelephorales and Amanitaceae. In contrast, the
resistant propagule community was dominated by
Rhizopogon species and by species of the Ascomycota.
Only one species, Tomentella sublilacina
(Thelephorales), was common in both communities. The spatial
distribution of mycorrhizae on mature roots and propagules in
the soil differed among the dominant species. For example,
T. sublilacina mycorrhizae exhibited a unique bias
toward the organic horizons, Russula brevipes
mycorrhizae were denser and more clumped than those of other
species and Cenococcum propagules were localized,
whereas R. subcaerulescens propagules were evenly
distributed. We suggest that species differences in resource
preferences and colonization strategies, such as those
documented here, contribute to the maintenance of species
richness in the ectomycorrhizal community.
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