A research group from Kobe University, the University of Tsukuba, and the University of Toyama has reported that it takes at least 75 years for grasslands regenerated from forests to recover plant and insect diversity to the same level as older grasslands.
Grasslands are valuable habitats for plants and the insects that feed on them. However, unlike natural grasslands that can exist without human management, semi-natural grasslands that have been maintained through human management will quickly turn into forests once management is no longer in place. Due to the decline in grassland use and abandonment of management associated with modernization, grasslands are rapidly being lost, and grassland flora and fauna are at risk of extinction. For this reason, efforts are underway to reintroduce management to former grassland sites that have become forests, and to regenerate grasslands.
In this study, we focused on grasslands that are managed and maintained as ski resorts, and investigated the flowers and insects that visit the flowers in newly constructed ski resorts (regenerated grasslands) and ski resorts that use old grasslands as they are (old grasslands).
As a result, it was found that regenerated grasslands had fewer plant species than old grasslands, and that the number of flowering plant species increased as the grassland continued for a longer period. In addition, there were more flies in the regenerated grasslands, which help pollinate plants, and the number of bees and butterflies increased as the grassland continued for a longer period. It was shown that the diversity of these plants and pollinators was equivalent to that of old grasslands in regenerated grasslands maintained for approximately 75 years.
On the other hand, the degree of specialization (the higher the degree, the more specialized the relationship between plants and pollinators) was also lower in the restored grasslands, and the longer the grassland continued, the greater the recovery. However, even after 75 years, the level of the old grasslands had not yet been reached. This suggests that it will take an enormous amount of time to restore the grassland ecosystem to the level of the old grasslands.
In the future, it will be necessary to prioritize the conservation of the remaining ancient grasslands, and it is hoped that effective management approaches will be identified to restore grasslands teeming with life.
Paper information:[Journal of Applied Ecology] Long-term management is required for the recovery of pollination networks and function in restored grasslands
