Mycorrhiza, vegetative mobility and responses to disturbance of alpine plants in the Northwestern Caucasus

The hypothesis of a trade-off between vegetative mobility and mycorrhizal i nfection has been examined. The rate of root arbuscular-mycorrhizal (AM) in fection and the extent of vegetative mobility (clonal with annual mobility more than 2 cm, clonal with annual mobility less than 2 cm, and non-clonal) was determined for 77 species in four alpine grassland communities in the Teberda Nature Reserve, the Northwest Caucasus, Russia. The percentage of A M species was similar (74-77%) in all four communities. The mean rate of AM root infection did not differ significantly between four communities. It w as shown that vegetatively mobile species (annual mobility > 2 cm) had on a verage a lower rate of root AM infection than species with low or no vegeta tive mobility. Our results conform with the mycorrhizal infection-vegetativ e mobility trade-off hypothesis. Gap-prefening species in a highly disturbed alpine meadow (burrowing activi ty of small and large mammals) had lower rate of root AM infection than spe cies preferring undisturbed microsites. This pattern was also found within two larger families, viz. Poaceae and Asteraceae.