ZONATION OF SPECIES AND MICROHABITATS IN MANGROVES OF NEGOMBO LAGOON

Abstract

Mangroves are an extremely important coastal resource both economically and environmentally. In most o f natural mangrove areas (large and undisturbed mangrove areas) it is observed that there is distribution pattern. The zonation pattern affects for generate the microhabitats within the mangroves such as fungi, algae, epifauna in root system, as well as macro benthos, soil macro fauna and etc. Objectives o f this project were to identify the major factors that affect of zonation pattern in mangroves and study the functional inhabition in microhabitats in various zones of Kadokele mangrove reservoir o f Negombo lagoon.Physical and chemical factors affecting for the zonation was studied in three major zones such as Avicennia, Lumnitzera and Rhizophora.Microhabitats for infauna (macro benthos) and epifauna (crabs) were studied in all three zones and attempts were made to get a relationship between diversity o f microhabitats and faunal density. Minimum pH was 4.54 - 4.77 which was observed in the water front zone of the Avicennia zone. Maximum pH was observed in the inland location of the Lumnitzera zone (6.56 — 7.00).Minimum salinity was observed Lumnitzera zone while maximum salinity was observed in Avicennia zone. Maximum carbon content was observed in the location II of the Avicennia zone and minimum carbon content was observed in the location I of the Lumnitzera zone more 'tidal inundation was experienced in Avicennia zone. Most diverse microhabitats were recorded in the water front zone of Avicennia for both epi fauna and infauna. Major factors affecting zonation of mangroves of Kadolkele mangrove reservoir of Negombo lagoon are soil salinity, soil pH, soil texture and tidal influence. Water front location of Avicennia zone provides more microhabitats for macro benthos while epifauna such as crabs were much prominent in both Avicennia and Lumnitzera zones. Microhabitats for such epifuanal species have being created according to the behavioral patterns o f the same animals.