Light, temperature, rainfall and wind all have a strong influence on the mangroveecosystem. Apart from playing a significant role in the development of plants andanimals, they also cause changes in other physical factors such as soil and water.LightLight is vital for photosynthesis and growth processes of green plants. It also affkctsthe respiration, transpiration, physiology and physical structk of the plants. Lightintensity, quality and duration are factors known to be important to plants. Ingeneral, mangrove plants are long-day plants and require high intensity of fullsunlight (Macnae, 1968; Du, 1962). This makes tropical coastal zones an idealhabitat. The range of light intensity which is optimal for the growth of mangrovespecies, is 3,000-3,800 Kcavm?/day. ‘Ibis is determined according to the variationsof light intensity recorded in different areas, from 3,000 Kcal/m2/day in mangroves .of Rookery Bay in Florida,,USA (Lug0 and Snedaker, 1974) to 3,800 Kcal/m2/dayin mangroves of southern Vietnam (National Academy of Science, 1974).IClarke and Hannori (1971) observed that long hours of shade harm seedlings whileinadequate light exposure impedes plant growth and increases the death rate.Soohhuae (1978), by planting some mangrove species in heavy shade andAksomkoae (1975), by planting some mangrove species in unsheltered areas,revealed that Rhtiophora mucronata, Rhizophora apicdata and Brugtderu spp.grown in shaded areas showed slower growth rates and a higher death rate. Undershelter, the annual height growth rate for Rhizophora mucronata was 28 cm,Rhizophora apicdata was 38 cm and Bnguiera spp. was 39 cm, wmpared withcorresponding figures of 66 cm, 67 cm and 60 cm, respectively, under fkll sunlight.In contrast, death rates of these 3 ‘species were very high under shelter : 18%, 8 1%and 80%, compared with only 4%, 5% and 9% respectively, for those in the openarea. Light also afiects the flowering and germination of mangrove species. Thosegrowing in outer fkinges of the plantation
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