Assessing the Contribution of Floating Vegetation Mats to Habitat Formation in Tropical Marshlands

Mats of floating vegetation are characteristic structural habitats within tropical marsh systems, where floating stems and leaves, along with submerged roots and entangled organic matter, give rise to a complex of microhabitats. The floating mats can serve as a refuge and source of food and substrata for aquatic invertebrates, as well as affecting the flow of water and processes of organic matter cycling in the vicinity. The role played by the structures could be affected if the mats are fragmented into isolated patches by drainage, changes in water level, physical disturbance, or invasive plant removal. In this paper, we will attempt to evaluate the contribution of floating vegetation to the creation of habitats, and establish an ecological context for the effects of fragmentation on the dispersal and colonization of aquatic invertebrates. Publications between 2014 and 2022 have been reviewed in the context of the structure of the vegetation, habitat heterogeneity, dispersal strategy, isolation of the patches, and wetland connectivity. Thus, fragmentation will have different impacts on different taxa, as aerial dispersal will be easier for mobile species than for taxa relying on aquatic transport or short-distance dispersal mechanisms. However, small patches may act as stepping stones when the appropriate distance, water flow, and habitat quality are available. The paper differentiates between theoretical expectations and experimental findings, and highlights the variables necessary to test the theoretical predictions, which include patch area, distance between patches, root abundance, water quality and invertebrate communities. The retention of a diverse but connected vegetation pattern in tropical marshes is suggested as a management principle.