Elements of the Structure of Macrophyte Metacommunities in Coastal Wetlands: Relationships With Limnological and Climatic Variables

ABSTRACT The Elements of Metacommunity Structure (EMS; coherence, turnover, and boundary clumping) framework allows the evaluation of species distribution patterns, including Clementsian patterns (discrete communities) and Gleasonian patterns (individualistic responses to environmental gradients). Quasi‐structures can also occur, representing intermediate patterns when results do not fully fit a specific model, such as stochastic species loss (quasi‐nested) or quasi‐Clementsian and quasi‐Gleasonian patterns. We applied the EMS to the total macrophyte metacommunity and to three functional groups (emergent, floating, and submerged) across 29 coastal wetlands in southern Brazil. We first hypothesized that the total metacommunity would show a Clementsian pattern driven by environmental heterogeneity and climate, with high turnover and well‐defined community boundaries. Our second hypothesis was that emergent species would form Clementsian communities, whereas floating and submerged groups would follow Gleasonian patterns driven by limnological gradients. After applying the EMS, we used regression trees to assess environmental influences on the observed patterns. The total metacommunity exhibited a Clementsian pattern, with clustered turnover and discrete boundaries influenced by mean annual temperature and total phosphorus. Emergent species also showed a Clementsian pattern shaped by temperature. Floating species, influenced by total phosphorus and altitude, exhibited a quasi‐nested, stochastic species loss structure, indicating a tendency toward nestedness without complete ordering. The submerged group, determined by temperature, exhibited a Gleasonian pattern with turnover and random distribution of species ranges. Our findings highlight the influence of environmental and climatic variables on macrophyte structure in wetlands, revealing distinct functional group responses and enhancing the understanding of species distribution in continental aquatic environments.