Yakushima has been isolated from the mainland since the last ice age 10,000 years ago. Although the flora and fauna that crossed the landbridge at that time are limited, the climate ranges from subtropical at the coasts to subalpine at the summits, and the resulting echosystem is truly unique.
They say that Yakushima is representative of all the biomes in Japan, with Okinawa-esque tree ferns, banyan trees, and even mangroves near sea level, and a harsher climate similar to Hokkaido in the central mountains. They say Yakushima has a vertical distrubution of flora, which played a large factor in selection for world heritage.
Particularly noteworthy is the mixed broadleaf evergreen forests at lower elevations. These forests contain laurels and ilex and quercus and castinopsis and a host of other species, so that they look a bit like a patchwork of broccoli when viewed from a distance. Such forests used to cover much of Asia, from east Napal to Tokyo. But, particularly in the 20th century, and especially visible in China, broadleaf evergreen forests have been all but completely cleared to make room for more profit-generating trees. Yakushima's broadleaf evergreen forest is now one of the largest remaining in this part of the world.
Higher up the forests are dominated by conifers: The famous cryptomeria called Yakusugi, as well as giant fir, spruce, and Japanese cypress trees. Even higher up the trees give way to bamboo grass and Yakushima Rhododendrons. These rhododendrons are considered sacred, and branches brought back by the semiannual pilgrimages are passed around the villages. They have also been selected as the world's top rhododendron by the Rhododendron Group of the British Royal Horticultural Society.
At all elevations, there are endemic species and subspecies as well as endangered flora with distributions restricted to southern Kyushu. These range from the white pine tree--found only in Yakushima and Tanegashima and traditionally used for dug-out canoes--to the Yakushima gentians that grow only on the highest rock faces of the central mountains.
However, certain flora--beech trees--are blatently absent. It is hypothesized that if beech trees had made it as far south as Yakushima during the ice age, they would dominate the forests today because they grow so well in dim conditions created by the thick canopy.
Down on the coastal plains, an assortment of crops can be raised in the warm climate, but farmers must work against rocky soil and typhoons. Major crops include yams, tangerines, tea, and turmeric, but you'll also find passion fruits, papayas, rice, and the occassional sugarcane patch.
Like the flora, certain animals are remarkably absent: Yakushima has never known large predators like bears or wolves. And although there are venomous pit vipers, the dreaded Habu snake of the Amami Islands and Okinawa is also absent. I often find that birders come here with high hopes, but more often than not leave disappointed by the species they are able to spot. However there are so many deer and monkeys that they are culled, and a trip to Yakushima is hardly complete without seeing at least one deer or monkey. From just before the rainy season until early summer, sea turtles come to lay their eggs, with the hatchlings scampering down the beach from July through late summer. In the summer months, both children and insect collectors are also out with their nets, searching for stag beetles as well as rarer endemic beetles.
- Do not collect plants.
- Please do not take back leaves and plants (dead or alive) from along popular trails. If you want a living souvenir, visit the "Comprehensive Nature Park" (the nursery) in Miyanoura.
- Try tropical fruits!
- To enjoy tropical fruits, visit roadside stands, (Prices start at 100 yen for unmarked produce.) or the Fruit Garden "agriforest" in the southwest town of Nakama. Be warery of the "monstara" if you don't know how to eat it!
- Hike at different elevations.
- If you're on the island for several days, go on hikes at different elevations.
- Don't start fights with monkeys.
- Be careful not to startle the monkeys, and avoid holding eye contact with them. If they feel threatened, they may charge you, but this is mostly a bluff.
- Don't corner animals.
- In areas where they are not hunted, deer and monkeys are likely to go about their business even when they know humans are close by. Some may even tolerate being approached. However, if you encroach to closely or suddenly, or if the animal feels trapped, it may act defensively.
- Do not allow the animals access to human food.
- That's a sure way to convert charming wildlife into pesky brats.
- Give sea turtles their distance
- They need their space and artificial lights can disorient them easily. If there is a guide or volunteer present, they will let you know when you can approach safely.