Drivers of macrophyte community structure in subtropical artificial rural ponds with contrasting land use intensity

Macrophyte communities play a key role in aquatic biodiversity, water quality, and biogeochemical processes. In this study, we assessed how land use intensity (LUI), landscape connectivity, and local pond characteristics influence macrophyte composition and community structure in 30 artificial rural ponds in Uruguay, organized into five pondscapes with contrasting grazing intensity. Although many species occurred under both LUI levels, LUI significantly affected beta diversity, mainly through species turnover. It emerged as the primary driver of macrophyte community structure, outweighing other factors such as connectivity. High-LUI ponds exhibited lower alpha diversity and were typically dominated by free-floating macrophytes in both cover and biomass. In contrast, low-LUI ponds showed higher taxonomic and functional richness, with a predominance of submerged macrophytes, likely due to greater light availability and lower concentrations of nutrients and suspended solids. Because free-floating and submerged macrophytes have contrasting effects on biodiversity, water quality, and carbon cycling, these findings highlight the importance of incorporating artificial rural ponds into monitoring and conservation strategies. Management efforts should prioritize local-scale actions that maintain environmental heterogeneity at the landscape level, thereby promoting biodiversity at both local and regional scales.