The species currently listed as rare plants are roughly divided into two types. The populations of one type of rare plants (including Pellionia minima Makino) have decreased due to habitat changes (e.g., from a wet environment to a dry environment) by human-driven development. The populations of the other type of rare plants (including disturbance-dependent species) have decreased because they are unmanaged. The former type of plants is stress tolerance-strategy or competition-strategy species, whereas the latter is only ruderal-strategy species. The stress tolerance-strategy or competition-strategy species do not need management after the protection period ends, but the ruderal-strategy species require adaptive management even after the protection period expires. The protection period of P. minima (a stress-tolerant competitor) is estimated to be approx. 1 year after transplant because P. minima have sufficient ecological adaptability and resilience, and growth in these plants is confirmed roughly 1 year after transplant.
