Evaluating Conservation Grazing Through Fine-Scale Vegetation Structure in Invaded Marsh Meadows

Active conservation management is widely applied in ecosystems affected by biological invasions, where outcomes depend primarily on how management regimes shape the vegetation structure. Grazing is a common tool in floodplain marsh meadows, but differences between grazing regimes are rarely assessed at spatial scales sensitive to internal community organization. Here, we compared the fine-scale structural diversity of two Amorpha fruticosa-invaded marsh meadows managed under contrasting conservation grazing regimes differing in livestock species, grazing intensity, and grazing dynamics. Vegetation was sampled using microcoenological methods along circular transects of contiguous 5 × 5 cm microquadrats. The fine-scale structure of the vegetation was quantified using the Juhász–Nagy spatial series framework, focusing on compositional diversity (CD) and associatum (AS), complemented by Shannon diversity. Differences between grazing regimes were evaluated using nonparametric tests complemented by effect size estimation. The patterns of species occurrence and Shannon diversity were similar between sites, indicating a similar species composition. In contrast, JNP-derived structural metrics showed consistent directional differences, with moderate to large effect sizes for selected structural indicators, despite nonsignificances. These results indicate that conservation grazing primarily influences fine-scale structural organization rather than species composition, highlighting the value of structure-oriented metrics in evaluating management effects in invaded marsh meadows.