The effects of the growth of grassland plants which flower in the spring compared to the difference of the long-term mowing management of semi-natural grasslands in the Hokuso region of Chiba Prefecture in Japan

Abstract

In this study, we aimed to investigate the habitat of grassland plants which flower in the spring, compared to the difference of the long-term mowing management of semi-natural grasslands in the Shimousa plateau in the Chiba Prefecture of Japan. In grassland plants which flower in the spring, Ranunculus japonicus and Lathyrus quinquenervius were found in the section mowed 1 time per year according to the May survey. However, the appearance frequency and presence of Potentilla freyniana, Potentilla fragarioides，and Polygonatum odoratum were high in the sections mowed 3 ～ 4 times per year. We considered that in Ranunculus japonicus and Lathyrus quinquenervius, their germination and growth are suppressed gradually, their roots decline, and plants will not grow soon. Potentilla freyniana, Potentilla fragarioides，and Polygonatum odoratum have grown under good sunshine with low-medium herbaceous conditions, and have adapted repeating seed dispersal and vegetative propagation in the environment of mowing 3 ～ 4 times per year for more than 20 years. Many Luzula capitata and Ixeris dentate were found in the environment that conducted excessive mowing of 10 times or more per year for more than 10 years. These species have developed repeating seed dispersal and vegetative propagation under the environment of intense mowing pressure for a long time, not being suppressed. On the other hand, Pteridium aquilinum, Potentilla fragarioides, Potentilla freyniana, Chaenomeles japonica, and Imperata cylindrica have grown, adapting to the cover of tall herbs. We considered that the appearance of grassland plants which flower in the spring has been affected by the differences of continuous mowing frequency for a long time and the presence or absence of the inhibition of high-stem herbaceous plants by mowing frequency after blooming and fruitage.