Plant species colonization in newly created road habitats of South Korea: Insights for more effective restoration

Abstract

Despite the advances in restoration methods for newly created road habitats such as roadcuts and embankments, implementation in different parts of the world is limited by high cost and lack of knowledge of naturally formed plant communities. However, a cheaper alternative is to relay in natural successional process in sites under optimal conditions. Thus, the first steps should focus on identifying plant species that colonize roadways and road habitats as well as optimal colonization sites. Our study aimed to describe species composition, exotic species presence, and diversity among four roadways (Jeongok-Youngjung, JG; Seolma-Gueup, SM; Singal, SG; and Samga-Daechon, DC) and three habitat types (embankments, plain areas, and roadcuts) in South Korean peninsula. The effect of some environmental factors on plant composition was also examined (soil type, soil slope, and surrounding landscape). Our results showed that established plant species composition was influenced by the interaction between roadways and habitats types, which was also the main interaction affecting plant richness and evenness. Surprisingly, environmental variables had no effect on plant species composition, with a residual amount of explained variation. A total of 48 plant species were described as indicator of different roadways and habitat types, and 50% of them were invasive or cultivated species. It appeared that different regional-dependent processes, such as northern vs. southern roadways, interact with local process in new-road habitats, producing complex patterns of plant species colonization and composition. Thus, ecological restoration solutions should be targeted at site-specific needs (local) while taking into consideration the differences between northern and southern roadways (regional). Here, regional-pool and local-constraints interaction controls plant composition and diversity during road construction in South Korea. Finally, new restoration actions should be based on plant species that have been established spontaneously in these degraded areas.