2018 Volume 43 Issue 3 Pages 484-498
In order to understand a tendency of the vegetation formed by natural plant invasion method, we surveyed the vegetation formed on green slopes, number of months after the construction, climate factors, constructional factors, and conditions of the plant community in 129 sites in 68 study regions from Aomori to Okinawa prefectures. As a result of classifying the vegetation formed on the green slopes by two-way indicator species analysis, the plant community is grouped into 7 types and they are also grouped into warm-temperate zone and cold-temperate zone. In the warm-temperate zone with small rainfall, as for the embankment slopes and the cut slopes whose periods after the constructions are shorter, the former have formed a crabgrass community and the latter have formed a horseweed community while slopes whose period after the construction in the same region is longer have formed a Japanese sumac community and the grounds of gravelly soil and soft rock have formed a Japanese red pine community. Also, it has formed a Japanese mallotus community in the same region with large rainfall. In the cold-temperate zone with large rainfall, the grounds of loam have formed a weigela community while the grounds of soft rock have formed a pussy willow community in the same region with small rainfall. As for number of appearance of species and percentage of vegetational covers, both show increase tendencies over the passage of the periods after the construction and show low values on surveyed slopes in the pussy willow community and in a part of the red pine community but an erosion of the slopes has not been observed.While herbaceous species which generated a lot in early times after the construction show a decrease tendency over the passage of the periods, arbor species show an increasing tendency over the passage of the periods and show a high percentage of vegetational cover with an increasing an establishment of arboreous buried soil seeds after the construction, and they indicate a continuous transition to arbor community.
