A self-assembling ecosystem
The floating islands of Indawgyi Lake are buoyant mats of vegetation and peat that drift across the water surface. These formations, known scientifically as sudds, begin with aquatic plants like water hyacinth (Eichhornia crassipes), water lettuce (Pistia stratiotes), and water fern (Salvinia cucullata) colonizing the lake. Their roots and rhizomes weave together, trapping sediment and decomposing organic matter. Over many years, this process builds up a thick layer of peat, a soil-like material with high organic content.
The buoyancy of these islands comes from their physical structure. The porous peat traps gases, such as methane, released during the decomposition of plant material deep within the mat. This trapped gas acts like a life preserver, keeping the entire mass afloat. The islands are substantial enough to support a succession of larger plants, starting with grasses and eventually including shrubs and trees like teak (Tectona grandis) and various Dipterocarpus species. These larger plants anchor themselves in the dense peat, creating a stable, mobile ecosystem. The entire Indawgyi Biosphere Reserve, which includes the 260-square-kilometer lake, was designated a UNESCO site in 2017.