Palynological records of mangrove degradation around Chilka Lake, Orissa, India

Abstract

The pear shaped Chilka Lake lying along the eastern coast of Orissa State, is one of the ecological and socioeconomical important wetlands of India. This open lagoon is identified as a nationally important and internationally renowned ecosystem, which harbours a range of marine, brackish and fresh water biodiversity. Palynological syntheses based on the results of investigated mid-late Holocene profiles (Balugaon, Rambha, Nalabana, Dangmal, Solari, Chandrapur, Geokhala, Bhowania) are compared with the upper part of core CHI-9 encompassing period of 13,000 years. It has been observed from the pollen record that tropical dense mangrove forest thriving luxuriantly during early Holocene has decreased considerably with the passage of time. The present mangrove ecosystem, though more restricted, is fairly stable with maintenance of conserved mangrove forests in protected prograding bays in Mahanadi delta and in estuaries kept open by adequate river flow. However, siltation, eutrophication and industrial development are major threatening factors affecting the sensitivity of lake resulting in shrinkage and total disappearance of surrounding vegetation. It has been indicated that certain metals, such as Co, Cr, Cu, Ni, V, Zn As, Pb, Cd are responsible for the environmental stress of the ecosystem which are continuously incorporated by the use of fertilizers and pesticides in agriculture. There should be an appeal and educational effort to stop the destruction and fragmentation of mangroves. The planned eco-friendly rehabilitation of mangroves, along with harmonious urban development and industrialization is required in order to restore the past glory of Chilka Lake.