Abstrakt
Although many studies have demonstrated great variation in the life histories of various perennial plants between years and habitats, current studies on sustainable harvesting of medicinal plants have only lasted two to four years. We explored the effects of harvesting on the survival of populations of highly used perennial medicinal plants (Rheum acuminatum and R. australe) that are endemic to the Himalayan region.
We collected data on recruitment, growth and survival in populations of R. acuminatum in open and forest habitats as well as R. australe in open habitats over six years in central Nepal. We used a matrix modelling approach to compare population growth and the effect of different harvesting regimes on population survival.
Although the population dynamics among the studied Rheum species in the two habitat types and among various years of the study were relatively similar and stable, there were significant differences in sensitivity to harvesting. The results of our study suggest that harvesting of both species can be considered sustainable under certain conditions.
Either selective (only vegetative or only flowering individuals) or rotational (once every five or more years) harvesting strategies should be adopted. Optimal management, however, partly differs between species and strongly depends on habitat conditions.
The conclusions of this study could also be applied to other commonly harvested alpine and perennial medicinal plants in the Himalayan region.