page_title: Rhizopogon salebrosus
hierarchical_section_title: Rhizopogon salebrosus
caption_attribution_description: English: Rhizopogon sp. from Sierra de Valdemeca, Cuenca, Spain.
context_page_description: Rhizopogon salebrosus is a mushroom species within the Rhizopogon sub-genus Amylopogon. R. salebrosus is a monotropoid mycorrhiza that is of vital importance to the ecology of conifer forests, especially in the Pacific Northwest region of North America. Although it is native to North America, R. salebrosus has been found in Europe and it's range is generally limited to mountainous regions with sufficient precipitation. The mycoheterotrophic plant, Pterospora andromedea is often found in an obligate association with R. salebrosus in western parts of the U.S. Eastern populations of P. andromedea are typically symbiotic with another Rhizopogon sub species, R. kretzerae.
  Species that form these mycoheterotrophic relationships like P. andromedea and R. salebrosus benefit one other by sharing essential nutrients. For example, ectomychorrizal plants contribute up to 30% of their fixed carbon in exchange for nitrogen that their host fungi absorb from the soil. Mycoheterotrophic plants can only be found in the tropics, though several members from Ericaceae and Orchidaceae do occur in temperate forests.
context_section_description: Rhizopogon salebrosus is a mushroom species within the Rhizopogon sub-genus Amylopogon. R. salebrosus is a monotropoid mycorrhiza that is of vital importance to the ecology of conifer forests, especially in the Pacific Northwest region of North America. Although it is native to North America, R. salebrosus has been found in Europe and it's range is generally limited to mountainous regions with sufficient precipitation. The mycoheterotrophic plant, Pterospora andromedea is often found in an obligate association with R. salebrosus in western parts of the U.S. Eastern populations of P. andromedea are typically symbiotic with another Rhizopogon sub species, R. kretzerae.
  Species that form these mycoheterotrophic relationships like P. andromedea and R. salebrosus benefit one other by sharing essential nutrients. For example, ectomychorrizal plants contribute up to 30% of their fixed carbon in exchange for nitrogen that their host fungi absorb from the soil. Mycoheterotrophic plants can only be found in the tropics, though several members from Ericaceae and Orchidaceae do occur in temperate forests. These unique mycoheterotrophic associations are thought to have evolved due to low light availability on the forest floor.
  Competition among ectomycorrhizal species plays an influential role in the composition and distribution of Rhizopogon species and the plants they associate with. Abiotic factors such as soil chemistry and soil moisture affect ectomychorrizal assemblages, however much less is known about the biotic factors that determine their composition other than host specificity. One study compared the competitive advantage between Rhizopogon salebrosus and Rhizopogon occidentalis. Each Rhizopogon species was introduced to Pinus muricata seedlings and the root tip biomass of each species was determined every few months. This was possible because a number of seedlings were planted in microcosms with only R. salebrosus, only R. occidentalis, or both R. salebrosus and R. occidentalis and grown under the same conditions. Some seedlings were then harvested every 2 months, the soil was rinsed from the root mass, and then the percentage of fungal occupation of their roots was determined using molecular sequencing. They found that R. occidentalis had similar root tip biomass when grown alone or in the presence of R. salebrosus. However, R. salebrosus had significantly less root tip biomass when grown in the presence of R. occidentalis than when grown alone, indicating it as a competitive inferior. Another study involving the same two Rhizopogon species examined the beneficial effects they imparted to their host plant. They found no significant difference in growth, survival, or percentage leaf nitrogen of seedlings colonized with either R. salebrosus or R. occidentalis. However, plants inoculated with both ectomychorrizal species showed significantly higher growth and percent leaf nitrogen compared to seedlings without ectomychorrizal fungus. Another interesting aspect of ectomycorrhizal competition are the strategies used to persist over long periods and colonize during unfavorable conditions such as drought or wildfire. Fungi are able to disperse and propagate with the help of spores and sclerotia which are able to remain dormant in the soil for some time, although their longevity is not well understood. In one a study the viability of fungal propagules was tested by collecting soil samples from the forest and aging them for six years. While the colonization rate was low, R. salebrosus was identified as a species able to survive in the soil for at least six years.
  Distribution of species is a prevalent topic, especially as climate change continues to alter forest ecosystems. Within the Deschutes National Forest, Oregon, USA, the historic range of Pinus contorta is steadily changing due to increasing temperatures and drought, declines in winter precipitation and snowpack. These environmental changes may have facilitated the migration of Pinus ponderosa into P. contorta territory. Observations such as these have led to studies exami
caption: Rhizopogon sp. from Sierra de Valdemeca, Cuenca, Spain
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