Its fabulous nature even among Okinawa Islands, the subtropical islands. The whole island is registered as national park, covered with dense forest, more than 40 rivers run through like a network. Almost 70% of Japanese mangroves are said to be in Iriomote Island, and at the mouth of the river, you can see unique view. By trecking in the mangroves, you will be astonished by the mistery of mangrove plants and numerous animals living there.
500 million years has passed since living things born in the sea have come to land. Plants adapted to various environment by evolving and evolving, and they florished on different places as sea side, mountains, tropical zones or frigid zones. Florishing on land, plants went further and further from the sea. The salt of sea water is "poisonous" for plant on land because it destroys them. Even sea side plants will wither in sea water.
At the mouthes of the river or sea side areas where mangroves are, the environment changes dramatically from sea to land due to the tide every 6 hours. Additionally, the soil lack of oxigen which makes it difficult for plants to invade. Nevertheless, the plants drived for the sea again. Some among them could attain special forms or functions. Nowadays, we can see rich forest of mangrove at the intertidal zone, which suspends from the mouth of river to sea side and shelf of coral.
The database of International Society of Mangrove Ecosystems, 74 species 28 genus 17 families on the world are listed (April 2016). Species among them which live only in intertidal zone are called genuine mangroves, they form genuine stocks and evolve special forms or functions adapted to tideland environment. Species which can survive at other environments are called semi mangroves, and they include plants such as palms or ferns.
Iriomote Island, most species of mangrove exist and form rich colonies. Furthermore, rare species that cannot be seen in tropical zones exist. On Iriomote Island, 70% of Japanese mangrove is said to gather, and 6 species 6 genus 4 families of all Japanese genuine mangrove can be seen. Compared to tropical zone, the size or height of colony are compact, but Iriomote Island has its own charm.
The reason why mangrove can live in mouth of river or intertidal zone is being revealed little by little. Each species attain functions to convey oxigen to its roots in the soil lacking of oxigen and to discharge salt outside its body. Let's check it with your own eyes. There is a beautiful mangrove forest near Hoshidate, a traditional village of Iriomote Island. You can see 5 genuine mangrove species and fern mangroves which exist only here in this island. The size of mangrove in Iriomote Island is appropriate to compare different species or to observe deeply.
Let's go with an interpreter. Their mission is not only showing the way or telling the names. They know that the visitors' greatest happiness is to "discover on their own". So, they will give you tips or advices how to interpret the phenomenon in front of you or how to observe wild animals. Of course, they will tell you specialized knowledge or the life of habitants. By joining intepreters' programs, you will obtain nice companionship with the nature by encountering various species.
Mangrove tide is a heaven for living beings. At first it may seem to be simple, but you will find out that it is a puzzle of various environment. You will be able to find dancing crabs, wandering fishes or shellfishes climbing trees. You will aslo be able to listen to their misterious music.
They are interpreters who organize eco tours such as mangrove trecking. Their job is not showing the way or telling the names, but to support "discovery", which is the biggest pleasure in fieldwork. If needed, they can explain specific knowledge. They also have programs to create traditional tools using plants of the island.