Abstract: Seasonally waterlogged grasslands are colloquially called vayals. These vayals in addition to providing various ecological services are valuable habitat and food source for many insects, amphibians , reptiles , aves and herbivore mammals. Due to high soil fertility this habitat is much sought after for agriculture . Most of the natural vayals have been converted into farmland resulting in loss of not only the valuable ecological services but also the invaluable biodiversity. What little of this habitat is left undisturbed is only in the wildlife protected areas. The status of the vayals inside Mudumalai Tiger reserve was evaluated by mapping the vayal area, documenting the area occupied by invasive and tracing the hydrological path. The study revealed that invasion of exotic species like Lantana camara and Chromolaena odorata into these vayals are a threat to the very existence of this ecosystem. Without proper conservation and management these wetlands would be lost for ever. A closer look at the complexity of these vayals may help us put proper management tools in place to ensure the conservation of these fragile ecosystems, before it is too late.