RESPONSE OF DIODIA VIRGINIANA (RUBIACEAE) APPLIED TO DAM RESERVOIR SLOPES AS A COVER PLANT, JAPAN

Abstract

Reservoir slopes of dams are typically bare or sparsely vegetated due to their steep inclination,
long-term submergence, marked fluctuation of water levels and impact of waves, which promote soil erosion
and cause water turbidity, deterioration of the landscape, and disrupt ecosystem functioning. Using plants to
stabilize slopes and prevent erosion is difficult, and the introduction of plants for this purpose has been
extensively debated. This study examined the effectiveness of Virginia buttonweed (Rubiaceae: Diodia
virginiana L.) for stabilizing the exposed slopes of the Matsubara Dam in western Japan- Diodia virginiana
was originally introduced to a 0.1-hectare experimental area on the dam slopes from 1994 to 1997. Since that
time, D. virginiana flourished; in 2008 it was widespread around the dam, growing in harsh environments
such as steep slopes and shoreline, and by 2016, the distribution and density of the species increased. These
characteristics of D. virginiana growth mean that the species is well suited for use as a cover plant for
preventing erosion on dam reservoir slopes.