The structure and dynamics of alpine plant communities in the Teberda Reserve, the Northwestern Caucasus

Abstract

Results of long-term ecological investigations in four different alpine communities are discussed The structure differs considerably between communities within the alpine zone. Meadows and grasslands with moderate snow depth have the highest vascular plant biomass and annual production. Plant productivity decreases in snow free communities (alpine lichen heaths) as well as in snow bed communities.
Populations of most of the alpine species consist of groups of all ontogenetic stages Soil seed banks in meadows and snow bed communities are greater than in grasslands and lichen heaths. Most of the alpine species (77%) have myconhiza. Vesicular-arbuscular mycorrhiza is most common. Seasonal dynamics, year-to-year fluctuations and long-term successions are discussed. Alpine lichen heaths have a specific spatial structure: lichen patches alternate with patches of vascular plants. The following hypothesis was put forward as an explanation of the structure: In poor shallow soils, the roots of vascular plants occupy larger area than their above-ground shoots do. Thust some vacant space becomes available for fruticose lichens as there is no significant competition for nutrients with vascular plants Several experiments (removal of lichens, fertilization, root cutting) was carried out to prove the hypothesis. Most of the alpine species were sensitive to the light deficit. Evergreen species were relatively tolerant of an artificial shading.