Ecologi cal and Envi ronment al Si gni f i cance

Ecologi cal and Envi ronment al Si gni f i cance

Mang ro ves’ falling leaves, flo wers and fruits supply mo re than three kilo g rams o f o rg anic matter per square metre per year, to be dec o mpo sed by bac teria and fung i and returned to the fo o d c hain. The bio diversity o f the dense mang ro ve ro o t systems multiplies the available spac e fo r o ther o rg anisms and o ffering them a large number o f micro habitats in a c o nfined spac e. Co untless fish, c rustac eans and bivalves po pulate the water. The ro o ts o f the trees are c o lo nised by alg ae, barnac les, o ysters, spo nges and mo llusc s. In the free- flo wing c hannels, pisto l shrimps and

Crafting o f a traditio nal Ja- ko tu

Do o rmates made o f c o ir

fish abo und. Larg e numbers o f fiddler

c rabs are fo und o n the silt surfac es. The upper sto reys o f the mang ro ve fo rest o verhead are ho me to reptiles, birds and mammals. Sea c o ws head fo r the sheltered mang ro ves to c alve, and mo nkeys c atc h c rabs o nto the sho re.

Numero us water birds inc luding c o rmo rants, king fishers, ibises, hero ns and frig ate birds take advantag e o f the ric h pic king s, and nest in the treeto ps. The pro tec tive mang ro ve buffer zo ne helps to minimize damag e to pro perty and lo ss o f life fro m hurric anes and sto rms. In reg io ns where these c o astal fring e fo rests have been c leared, lo ss o f human life and pro perty c an o c c ur due to destruc tive sto rms. Additio nally serio us pro blems o f ero sio n and siltatio n have arisen after felling the mang ro ves.

A primary facto r o f the natural enviro nment that affects mangro ves o ver the lo ng term is sea level and its fluctuatio ns. Beside the abo ve inco mparable advantages mentio ned, mangro ves pro vide a natural pro tectio n fro m the stro ng Tsunami waves. Co astlines with existing fo rests were no ticeably less affected by the Sumatra- Tsunami. Fo r instance, 200 metres o f mangro ves are able to scale do wn the po wer o f a wave to 75 % .

Other sho rter- term fac to rs are air temperature, salinity, o c ean c urrents, sto rms, sho re slo pe, and so il substrate. Mang ro ves have also been useful in treating effluents, as the plants abso rb exc ess nitrates and pho sphates thereby preventing co ntaminatio n o f nearsho re waters.

Ecologi cal and envi ronment al values of mangroves

◆ The bio diversity o f the dense mang ro ve ro o t systems multiplies the available spac e fo r

o ther o rg anisms, o ffering them a larg e number o f mic ro habitats. ◆ Pro vide breeding g ro unds and feeding g ro unds fo r many c o astal fishspec ies and

c rustac e ans. ◆ Pro vide nutrients to the c o astal water bo dies and maintain ec o lo g ic al balanc e o f the

c o astal ec o systems. Vital c o ral reefs and sea g rass beds are also pro tec ted fro m damag ing siltatio n.

◆ Pro tec t the sho reline fro m wave ac tio n, c urrents, winds and prevent ero sio n by ac ting

as buffers and c atc h alluvial materials, thus stabilizing land elevatio n by sediment

ac c retio n that balanc es sediment lo ss. ◆ Serves as a natural water treatment plant by retaining heavy metals. ◆ Trap se dime nts. ◆ Valuable reso urc e fo r researc h and educ atio n.

( by Pro f. Jayamanne)