Population genetics, systematics, and habitat associations of chanterelles in the Pacific Northwest.

摘要

Balancing resource extraction with protection of Pacific Northwest forest ecosystems requires understanding the population biology of ectomycorrhizal fungi. Design of landscape-scale management and research strategies requires understanding genet size, habitat requirements, and dispersal capabilities. The purpose of this dissertation was to gain knowledge about the distribution of genetic variation, systematics, and habitat associations of chanterelles (Cantharellus sp.). Population genetic markers were required to complete this research. I developed and characterized five co-dominant microsatellite markers and used them to study Pacific golden chanterelle ( C. formosus) genet size and its relation to forest disturbance. Genetic data indicated that C. formosus collections included a cryptic chanterelle species. Small (4 m diameter) genets were characterized for both genetic types and there was no evidence that genet size differed across disturbance treatments. Three genetic and one morphological data set were collected to determine if the genetic variability observed during the genet study was indicative of species boundaries. These data were used in combination to characterize a new species of yellow chanterelle, C. cascadensis nom. prov. Microsatellite data provide evidence that C. subalbidus, C. cascadensis nom. prov., and C. formosus do not interbreed when they co-occur spatially. Morphological data indicate that pileus color and stipe shape can be used to separate fresh collections of C. formosus and C. cascadensis nom. prov. I also determined the habitat associations of three chanterelle species with respect to stand age. At the watershed scale stand age is a good predictor of the distribution of C. subalbidus and C. formosus , but is only marginally important for C. cascadensis nom. prov. To characterize chanterelle dispersal capabilities I used spatial autocorrelation analysis to examine the within-population genetic structure of C. formosus. Positive spatial autocorrelation was detected estimating a 200 m radius for genetically homogeneous patches for C. formosus indicating that limited spore dispersal possibly coupled with inbreeding works to maintain fine scale genetic structure in this species.