THE CLONE ARCHITECTURE OF RUMEX-ALPINUS (POLYGONACEAE)

Rumex alpinus is a perennial species with a monopodial rhizome consisting of annual growth segments which are products of individual seasons. In nutrient-rich habitats R. alpinus is a strong dominant suppressing other species under its dense canopy. The rhizome pattern and dynamics of a stand of R. alpinus were studied in the Krkonose Mts, Czechoslovakia. Rhizomes of R. alpinus remain alive for 13.0 +/- 3.2 (mean +/- S.D.) yr. Segment width can be used as an estimate of shoot biomass since these variables are closely correlated. The long-term growth dynamics of R. alpinus stands was simulated by a stochastic model. This enabled prediction of a) the fate of individual ramets within the stand, b) the number of genets in the stand, c) successive changes in spatial pattern, and d) lateral extension of the stand. In the simulations, the survival of spatially isolated genets was much higher than that of genets in a closed-canopy stand where less than 30% of the original genets were alive after 30 yr. It is likely that most of the large stands of R. alpinus in the Krkonose Mts originated from a number of seedlings, and do not represent single clones. The spatial pattern of R. alpinus shoots is random in the field. The same pattern was reached in the simulations after 4 to 6 yr independent of the initial point pattern. The simulated lateral growth of a stand was 20-30 mm yr-1.