Introduction

Coastal ecosystems are transitional zones where the land meets the sea, and where diverse environmental factors such as tidal cycles, salinity, moisture conditions, and soil characteristics intersect to form unique vegetation structures and functions (Bertness & Shumway, 1993; Lee & Ihm, 2004). Among these, salt marshes, reclaimed lands, freshwater wetlands, and sand dunes are subject to different intensities of disturbance and stress, and such differences provide key insights for understanding the distribution and ecological strategies of plant communities in these habitats (Álvarez-Rogel et al., 2007; Lee & Kim, 2018).

Grime’s CSR theory (Grime, 1974) explains plant survival strategies along three axes: Competitor (C), Stress-tolerator (S), and Ruderal (R). With the subsequent establishment of quantitative procedures by Hodgson et al. (1999) and Pierce et al. (2007; 2013), the CSR model has become widely applied as a methodological framework to interpret the functional responses of plant communities to environmental stress gradients (Negreiros et al., 2014).

In Korea, several studies have applied the CSR model to various coastal habitats. Son et al. (2020) analyzed soil factors and plant functional traits in salt marshes on the southwestern coast and showed that many halophytes adopted CR or SC strategies. Yang et al. (2021) confirmed the dominance of R and CR strategies in the early successional vegetation of the Saemangeum reclaimed land. Park et al. (2025) compared freshwater wetlands, sand dunes, salt marshes, and reclaimed lands in Muan, identifying distinct CSR strategies by habitat type and reporting that R/CR strategies were particularly prominent in freshwater wetlands. Choi (2022) performed canonical correspondence analysis (CCA) on tidal flats and salt marshes in the southwest coast, demonstrating close correlations between soil factors such as salinity, nitrogen, and organic carbon and plant strategies, and confirmed the prevalence of CR strategies in many species. Recently, Choi et al. (2024) further explored the habitat gradient–plant trait relationships, emphasizing the need for expanded studies across coastal–inland transitional zones.

However, most previous studies have focused on individual habitats, and few have provided integrated comparative analyses of multiple coastal habitats in Korea from the perspective of habitat connectivity (continuum). In other words, comprehensive understanding has not yet been fully established regarding how the stress adaptation of salt marshes, disturbance responses of reclaimed lands, rapid expansion of freshwater wetlands, and intermediate strategies of sand dunes are interconnected along a single environmental gradient.

Based on previous findings, the present study aims to analyze the species composition and functional traits of salt marshes, reclaimed lands, freshwater wetlands, and sand dunes along the southwestern coast of Korea in an integrated manner, and to compare the distribution of CSR strategies. Through this, we seek to identify the functional adaptations of plant communities along disturbance and stress gradients, and to provide foundational data for the conservation and restoration of coastal and inland transitional ecosystems.

Materials and Methods

This study analyzed and utilized the results of previous works by Choi et al. (2024), Lee et al. (2020), Park et al. (2025), Son et al. (2020), Yang et al. (2021).

Results

Discussion

This study examined species composition and functional traits of plant communities across salt marshes, reclaimed land, sand dunes, and freshwater wetlands along the southwestern coast of Korea, applying Grime’s (1974) CSR theory to compare adaptive strategies among habitats. The findings revealed that distinct community structures and functional traits were closely associated with habitat-specific environmental drivers, including salinity, disturbance, water availability, and nutrient conditions.

In salt marshes, elevated salinity and tidal flooding promoted the dominance of halophytes such as S. japonica and S. europaea, which exhibited stress-tolerant or CR/SC strategies. Reclaimed land, shaped by unstable salinity and intense anthropogenic disturbance, was dominated by ruderal and naturalized species, primarily expressing R/CR strategies. Freshwater wetlands, under low-salinity, high-moisture, and nutrient-enriched conditions, supported large aquatic plants capable of rapid growth and dispersal, also reflecting R/CR strategies. In contrast, sand dunes, characterized by arid, oligotrophic conditions and sand mobility, favored dune specialists such as C. kobomugi and C. soldanella, which adopted intermediate CR/CSR strategies.

Overall, these results underscore the pivotal role of stress and disturbance gradients in shaping habitat-specific CSR strategies and functional traits. Furthermore, the coexistence of diverse adaptive strategies across the coastal–inland transition zone illustrates a critical ecological mechanism that sustains species diversity and functional stability in dynamic coastal ecosystems.

Conclusion

Overall, the findings highlight the pivotal role of stress and disturbance gradients in shaping habitat-specific CSR strategies and functional traits. The coexistence of diverse adaptive strategies across the coastal–inland transition zone illustrates a fundamental ecological mechanism that underpins species diversity and functional stability in dynamic coastal ecosystems.

This study thus provides a comprehensive comparison of habitats along the southwestern coast of Korea, revealing distinct species compositions and CSR strategies associated with specific environmental conditions. These results offer valuable insights into how transitional ecosystems sustain themselves through functional adaptation under accelerating climate change and anthropogenic disturbance.

In particular, CSR strategies exhibited a directional shift along the habitat continuum-from stress tolerance to disturbance adaptation, and further toward intermediate forms integrating competition, stress, and disturbance. This pattern underscores the importance of designing restoration and management strategies that are tailored to local environmental gradients and the functional traits of resident plant communities.

Future research should incorporate long-term monitoring and advanced quantitative approaches such as RLQ and fourth-corner analyses to refine our understanding of the linkages among environment, plant traits, and species composition. Such efforts will not only enhance ecological knowledge of the southwestern coast of Korea but also provide a robust scientific foundation for the conservation and restoration of transitional ecosystems worldwide.