Abstract: Wetlands provide immense environmental, economic, and social, benefits. Some of the wetland functions are surface water storage,
groundwater recharge, storm water retention, flood control, shoreline stabilization, erosion control, and retention of carbon, nutrients,
sediments and pollutants. According to the IPCC Second Assessment Report, changes in climate will lead to an alteration of the
hydrological cycle and could have major impacts on regional water resources. Climate change may also lead to shifts in the geographical
distribution of wetlands. Thus, the projected changes in climate are likely to affect wetlands, in their spatial extent as well as distribution
and function. Wetland responses to climate change are yet to be understood thoroughly and are often not included in global models of the
impact of climate change. India has a wide spectrum of wetlands ranging from high altitude alpine lakes, littoral swamps in the form of
mangroves, corals and numerous types of inland wetlands. To understand the impact of climate change on wetlands, the first step is to have
a spatial data base of existing wetlands. This paper highlights the wetland types and distribution in India created at 1: 250,000 scale using
Resourcesat-1 (Indian Remote sensing Satellite-P6) Advanced Wide Field Sensor (AWiFS) data of 2004-05. A two step hierarchical
classification was used to map the wetlands and categorise them into 25 classes. The total area under various wetland categories was
estimated as 11.69 Mha. Since a wide range of wetland types exist, it is difficult to accurately predict whether they will continue to
function as hydrological buffers for extreme events or provide other important ecological, social, and economic services. Therefore, only a
general assessment of the relationships between wetlands and climate change is addressed in this paper. Increasing temperatures globally
are likely to result in a warming of water temperatures in lakes and rivers. The greatest effect would be at high altitudes where biological
productivity would increase. India has some of the very unique high altitude lakes spread across the Himalayas. Rare and endangered plant
and animal species sensitive to small changes in temperature often have no alternative habitat, especially in isolated areas such as those in
montane and alpine wetlands. On the other hand many coastal wetlands will have impact of salinity and change the homeostasis of
ecosystem. The coral reefs are vulnerable to bleaching from sustained increase in Sea Surface Temperature (SST).

Abstract: Available evidences drawn from biosystematics, evolutionary biology, biogeography, archaeology, history, anthropology, paleo-geology and paleo-meteorology are pooled to reconstruct the series of events that led to the cosmopolitan cultivation of the Asian cultivated rice (O. sativa) and the regionalized planting of the African cultigen (O. glaberrima) in West Africa. The genus Oryza originated in the Gondwanaland continents and, following the fracture of the supercontinent, became widely distributed in the humid tropics of Africa, South America, South and Southeast Asia, and Oceania. The two cultivated species have had a common progenitor in the distant past. Parallel and independent evolutionary processes occurred in Africa and in Asia, following the sequence of: wild perennial?wild annual?cultivated annual. The weed races also contributed to the differentiation of the cultivated annuals. The corresponding members of the above series are O. longistaminataChev. et Roehr., O. barthiiA. Chev., O. glaberrimaSteud., and the 'stapfii' forms of O. glaberrima in Africa; O. rufipogonGriff., O. nivaraSharma et Shastry, O. sativa L., and the 'spontanea' forms of O. sativa in Asia. The differentiation and diversification of the annuals in South Asia were accelerated by marked climatic changes following the last glacial age, dispersal of plants over latitude or altitude, human selection, and manipulation of the cultural environment. Cultivation of rice began in many parts of South and Southeast Asia, probably first in Ancient India. Cultural techniques such as puddling and transplanting were first developed in north and central China and later transmitted to Southeast Asia. Wetland culture preceded dryland culture in China, but in hilly areas of Southeast Asia, dryland cultivation is older than lowland culture. The planting method progressed from shifting cultivation to direct sowing in permanent fields, then to transplanting in bunded fields. Widespread dispersal of the Asian cultigen led to the formation of three eco-geographic races (Indica. Sinica or Japonica, and Javanica) and distinct cultural types in monsoon Asia (upland, lowland, and deep water). Varietal types changed readily within the span of a millenium, largely due to cultivators' preferences, socio-religious traditions, and population pressure. Genetic differentiation developed parallel to the ecologic diversification process. The African cultigen developed later than the Asian cultigen and has undergone less diversification. The wild races in South America and Oceania retain their primitive features mainly due to lack of cultivation pressure or dispersal. Both the African and Asian rices are still undergoing evolutionary changes at habitats where the wild, weed, and cultivated races co-exist. © 1976 H. Veenman en Zonen B.V.