Does mycorrhizal specificity affect orchid decline and rarity?

Premise Of The Study: Orchids rely on mycorrhizal fungi for seed germination, and many species maintain associations during later stages in their life cycle. Because of the critical dependence of orchids on fungi it has been suggested that the degree of mycorrhizal specificity may be associated with rarity and long-term survival of orchid species, especially in highly degraded or fragmented landscapes. To test this hypothesis, we compared mycorrhizal communities in two species that differed significantly in decline in Belgium and other parts of Europe.

Variation in mycorrhizal associations with tulasnelloid fungi among populations of five Dactylorhiza species.

Background: Orchid species rely on mycorrhizal symbioses with fungi to complete their life cycle. Although there is mounting evidence that orchids can associate with several fungi from different clades or families, less is known about the actual geographic distribution of these fungi and how they are distributed across different orchid species within a genus.

Methodology/principal Findings: We investigated among-population variation in mycorrhizal associations in five species of the genus Dactylorhiza (D.