Distribution and abundance of aquatic macrophytes in a forested stream: Case study in Kottawa Forest Reserve

Forest ecosystems have been studied for terrestrial components and other faunal assemblages while information on aquatic plants on this regard is scarce. Thus, present preliminary study was designed to study the abundance, distribution and factors influencing on aquatic plant distribution in forested stream selecting “Gong Gawwa Ela” locate in the Kottawa forest reserve. Six sites were selected along a stretch of the stream (~1 km). Those sites were visited once in every month for a period of three months. For each site, plant distribution was observed in a transect across the stream perpendicular to the river bank. Water quality, water flow velocity and sediment composition at each site were also monitored. Eleven aquatic plant species were found along the stream while the most common species were Lagenandra thwaitesii, Aponogeton rigidifolius and Adiantum sp. A significant difference in plant diversity among study sites was noticed where the highest plant diversity was found in the most downstream site. Irrespective to the species; distribution of above three species exhibited a significant positive correlation to the sediment composition. Further, diversity of aquatic plant was significantly correlated to the abundance of L. thawaitsii. There was no significant difference in dissolved oxygen, pH, temperature and biological oxygen demand among study sites. Present study revealed that sediment composition and the abundance of L. thawaitsii are two factors that decide the architecture of the aquatic plant communities along this stream.