ABSTRACT
With the increase in severity and intensity of anthropogenic disturbances, the freshwater ecosystem is facing an unprecedented threat. Degraded water quality causes habitat shifts for most of the aquatic flora and fauna, causing enormous interruptions in the aquatic food chain and whole ecological processes. Lakes and wetlands along with their macrophyte assemblages provide aesthetic appeal, landscape diversity and recreational opportunities. Aquatic macrophytes contribute to the structuring and complexity of aquatic habitats, improve their richness and play a key role in sustaining their physical structure. Algae and macrophytes are used as bioindicators as they show a rapid shift in their diversity, richness and abundance with increasing trophic state and pollution threats, resulting in decrease in species diversity and increase in species evenness. Catchment-level stresses such as land use modifications also cause extinction of sensitive and native species of algae and macrophytes. For proper management of freshwater resources, an integrated approach should be followed, which includes assessment of water, pelagic, benthic and riparian biodiversity along with assessment of the ecological condition of lakes by combining hydro-morphological, ecological, and physicochemical aspects. All aspects of a freshwater ecosystem should be considered for management, restoration and conservation by policy makers and the government. This chapter will be helpful in understanding the concept of bioindicators and pressure–response relationships and various stressors that alter the trophic states of lakes. The assessment could further help in bridging the most important gap between restoration policy and practice, and also in making pragmatic management plans for freshwater ecosystems.
