PARENT SESSION
Oral Session #75: Plant Communities: Vegetation Analysis. Presiding: J. Fralish.
Friday, August 10, 2001. 8:00 AM to 12:00 PM. Hall of Ideas F.
Community and species responses to reciprocal transplants among four alpine habitats in northwestern Caucasus.
BLINNIKOV, MIKHAIL 1, ONIPCHENKO, VLADIMIR2, VOLKOVA, ELENA2, 1 2
ABSTRACT- Alpine communities are strongly controlled by abiotic factors (snowpack depth, growing season length, etc), but the degree of communities dependence on these factors must be experimentally assessed. We hypothesized that vegetation of moderate alpine habitats will show a strong negative response to an increase in habitat severity, while vegetation from the already severe habitats may show improved growth in the moderate habitats. Reciprocal transplants along a snowpack gradient provide a way to evaluate both direction and degree of communities and species response under such a scenario. One hundred and sixty 1-m sq. fragments from four alpine communities were reciprocally transplanted at 2800 m elevation in Teberda Reserve, northwestern Caucasus, Russia. Annual performance was monitored for ten years through species and shoot counts and biomass measurements. Overall, colonization rate of transplants was greater than the exclusion rate. As predicted, the severe tundra and snowbed habitats were the least favored with 0.65 species gain per plot on average, while the most favored was meadow habitat (three species gain). In terms of biomass and shoot counts, only about 48% of significant responses conformed to the predictions. Surprisingly, 30% of significant responses indicated preference for native habitat, even when those were severe ones. Also, we found that a few species actually preferred any non-native habitat to the parent one. We conclude that some biotic factors are involved in excluding such species from their optimal habitats.
KEY WORDS: abiotic factors, alpine communities, transplantation experiments, Teberda