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catastrophes. Such efforts should be made to enhance and promote ecologically and

environmentally sustainable integrated agriculture systems.
INTRODUCTION

Characterised by a unique blend of geographic, geologic, edaphic and climatic gradients, the
Western Ghats represent a distinct biogeographic zone in India and are known for their biotic

richness with a high incidence of endemism. The geological antiquity, evolutionary history
and biogeographic patterns, with special emphasis on the endemism of the flora and fauna of

the Western Ghats, have been discussed by several authors (Blasco,1970). This region

represents a primary or secondary centre of origin and diversification of wild progenitors and
wild relatives of several cultivated plants and domesticated animals. The region is rich, by

supporting about 145 wild relatives of crop plants belonging to 66 genera (Arora and Nayar,

1984).
A series of severe floods ravaged Kerala was considered to be the worst disaster in the state

in nearly a century .Ecosystems like aquatic, wetland etc. perform numerous valuable
environmental functions. They recycle nutrients, purify water, attenuate floods, augment and

maintain stream flow, recharge ground water, and provide habitat for wildlife and recreation
for people. Wetlands, one of the most productive ecosystems of the world, are rich in

floral and faunal biodiversity and harbor great number of species including several

endangered and threatened ones (Turner, 1991). Flooding results in excessive moisture in soil
which decreases oxygen levels. This impedes respiration in the roots leading to the build-up

of carbon dioxide, methane and nitrogen gases, leading to suffocation and death of the roots.
The deposition of soil and rocks onto plants during flooding can damage plants, as can the

exposure of roots to the air by the washing away of surrounding soil. Also, even after the
flood waters recede the damaged plants can be more vulnerable to other stresses. For

example, trees with substantial root damage are more likely to be uprooted in windy weather.

The damage caused to plants by flooding differs depending on the time of the year and the
age of the plants. Flooding can result in loss of plant-available nutrients through several

pathways: 1) surface-soil erosion can result in loss of valuable plant-available nutrients and

organic matter as runoff, 2) nutrients that are prone to leaching, like nitrate and potassium,
can be lost to groundwater and 3) gaseous losses of nitrogen can occur in water-saturated

soils through denitrification. Agronomic soil testing is recommended following flooding
events to assess soil plant-available nutrient contents. After periods of prolonged flooding,

phosphorus-deficiencies can occur even if soil-tests indicate adequate plant-available
phosphorus concentration, since flooding can reduce populations of soil microorganisms

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