Reproductive responses of alpine plants to grassland degradation and artificial restoration in the Qinghai-Tibetan Plateau

Artificial grassland establishment has been implemented in the alpine region of Qinghai-Tibetan Plateau in China as a mitigation tool against grassland degradation, one of the major environmental problems in this region. We hypothesized that both grassland degradation and artificial restoration may alter the reproductive modes of the alpine vegetation at the levels of individual species as well as plant functional groups. By investigating a long-term field study of grassland degradation and artificial restoration experiments, we found that alpine plants can maintain a highly plastic relationship between sexual and asexual reproduction, that is, the alpine plants in degraded grasslands increased their efforts towards sexual reproduction while those in artificially restored grasslands promoted their efforts in vegetative reproduction with in the year after restoration. The high reproductive plasticity of the alpine plants can be regulated through a number of mechanisms, which include changing proportion of clonal species in the plant composition, altering number ratio of sexual and vegetative propagules, shifting biomass allocation for sexual and vegetative reproduction at both individual species and functional group levels. These conclusions demonstrate how crucial it is to consider manipulation of reproductive modes needed to restore the structure and stability of degraded alpine grasslands.