10-Second Overview: Lanyu is the northern terminus of the Philippine volcanic arc, a waypoint for the Kuroshio Current, and the home of the Tao people—
as well as the most unfamiliar piece of Taiwan's ecological landscape.
The Island Brought by the Kuroshio
Sailing southeast from Taitung, after about 50 kilometers of travel, a powerful ocean current will sweep beneath your boat.
This is the Kuroshio Current—the world's second-largest ocean current. Originating from the Philippine Sea, it flows north along Taiwan's eastern coast before turning toward Japan. It carries warm, saline water and abundant plankton, delivering seeds, insects, and butterfly eggs all the way north.
Lanyu is a waypoint where the Kuroshio pauses on this journey.
With an area of only 45 square kilometers, this small island belongs geologically to the northernmost tip of the Philippine volcanic arc, separated from Taiwan by a deep-sea trench exceeding 3,000 meters in depth. No matter how much sea levels dropped during the Ice Age, this abyss never emerged as a land bridge. Lanyu has never been connected to Taiwan; instead, it maintains an eternal conveyor belt with the Batan Islands of the Philippines via the Kuroshio.
This explains why, when Japanese naturalist Tadao Shikano collected a species of weevil on Lanyu in 1927, he recognized it as a Philippine species rather than a Taiwanese one. The life on Lanyu has always arrived from the south.
(Further Reading: [Lanyu's Tropical Heritage: The Wallace Line and Tadao Shikano's Island Mystery])
Residents of the Tropical Frontier
Weevils: Walking Jewels
Lanyu is home to five species of Pachyrrhynchus (weevils). Their elytra are fused, meaning they cannot fly and can only crawl slowly through the forests. Because they cannot cross straits, they serve as the most reliable "living indicators" in biogeography—wherever they are found indicates a past connection between islands.
The metallic luster of their patterns serves as a warning color to predators: "I am unpalatable."
This strategy has worked for tens of
millions of years, yet it cannot withstand the pressure of human collection. Currently, all five species of Pachyrrhynchus on Lanyu are listed as protected species.
Common Birdwing: The Kuroshio's Messenger
Every spring, butterfly enthusiasts from Taitung wait on the forest paths of Lanyu for the appearance of a specific butterfly.
The Common Birdwing (Troides magellanus) is Taiwan's largest butterfly, with a wingspan of nearly 20 centimeters. The golden pearlescent sheen of its hindwings flows under the sunlight like flying amber.
Its distribution extends from northern the Philippines to Lanyu, carried by the air currents of the Kuroshio.
The larvae feed exclusively on Aristolochia (pipevine), and the adults have a brief lifespan, patrolling the forest at low altitudes. Due to habitat destruction and collection pressure, it is currently listed as a Class I protected species in Taiwan.
Lanyu Scops Owl: Guardian of the Night
After night falls, the forests of Lanyu belong to the Lanyu Scops Owl (Otus elegans botenteis).
This small owl is an endemic subspecies of Lanyu. Its call is low and rhythmic; the Tao people refer to it as a "ghost bird," with legends stating that if the scops owl cries on a rooftop, it signifies an impending death.
This taboo has inadvertently become an effective conservation mechanism. Out of reverence for the "ghost bird," the Tao people have not hunted scops owls for generations, allowing the population density on Lanyu to remain relatively stable to this day.
Coconut Crab: The Largest Land Arthropod
On forest paths at night, one might occasionally encounter a behemoth crossing the road—the Coconut Crab (Birgus latro). With a claw span of up to one meter, it is the largest land-living arthropod.
They can use their claws to crack coconuts, are capable of climbing trees, and can scent food from kilometers away.
While coconut crabs have become endangered on many Pacific islands due to overharvesting, populations still exist on Lanyu, partly because traditional Tao harvesting practices maintain a certain level of restraint.
The Logic of Flying Fish: Tao Ecological Wisdom
Every March, as the northeast monsoon weakens and the Kuroshio brings warm currents past the eastern coast of Lanyu, the elders of the Tao people observe the stars and ocean currents to announce the start of the flying fish season.
The tatala (plank boats) are launched, fishing fires are lit, and men head to sea at night, using lights to entice the flying fish to leap alongside the gunwales.
This is more than just fishing—it is an entire system of understanding and restraint regarding the ocean.
The Tao people maintain strict classifications and taboos regarding flying fish: which species can be fermented, which must be eaten immediately, which seasons require a fishing ban, and even which age groups of men are permitted to catch certain fish. This body of knowledge ensures the long-term stability of flying fish populations near Lanyu.
Modern marine ecologists studying the fishery resources around Lanyu have found that traditional Tao fishing seasons align highly with the migratory rhythms of the flying fish—this is no coincidence, but rather the accumulation of generations of Traditional Ecological Knowledge (TEK).
The Tao people's taboos regarding the Lanyu Scops Owl, their restraint in harvesting coconut crabs, and their reverence for sea turtles constitute an island ecosystem management system that, while not written in academic papers, has functioned effectively for hundreds of years.
Pressures on the Frontier
Lanyu is currently enduring pressures from several different directions.
Invasive species represent one of the most pressing issues. Lizards, domestic cats, and various plant seeds arriving in tourists' luggage expand rapidly in Lanyu's environment due to a lack of natural predators, compressing the habitat of native species.
Tourism pressure has intensified rapidly in recent years. Nighttime lighting brought by visitors disrupts the behavioral rhythms of scops owls and coconut crabs; road development fragments previously continuous forest habitats; and excessive snorkeling and trampling are damaging the coral reef ecosystems surrounding Luna.
Low-level radioactive waste storage: Since its activation in 1982, low-level nuclear waste has been stored long-term at the southern end of Lanyu. The Tao people's concerns regarding radiation leakage risks have never subsided, and the issue of relocation remains unresolved, becoming a heavy issue of justice beyond mere ecological conservation.
Climate change is the most long-term threat. Rising sea temperatures are causing coral bleaching in Lanyu's reefs, which serve as the foundation for the entire nearshore fishery. The Kuroshio brings life to Lanyu, but it may also take it away through warming waters.
A Frontier That Remains
The Tao people have a saying: Lanyu is called Ponso no Tao, "the Island of the People."
It is not a "nature reserve," nor is it a "tourist attraction"; it is a place where people live.
Within this naming lies an ecological philosophy: humans are part of the island ecosystem, neither its managers nor its mere observers. For centuries, the Tao people have shared this 45-square-kilometer volcanic island with weevils, Common Birdwings, flying fish, and scops owls, developing a logic of life unique to this place within the Kuroshio frontier.
That logic is currently being tested.
References
- Lin, Liang-kung, "Biogeographical Research on Mammals of Taiwan."
- Yu, Guang-hong & Dong, Sen-yong, Rituals and Seasonal Festivals of the Yami (Tao) Fishing Villages, Institute of Ethnology, Academia Sinica, 1998.
- Wang, C.-N. & Hsin, K.-T. (2013). "Between the Edge of the World: The Biogeographical Connection of Wallace," Taiwan Museum Quarterly, Issue 120.
- Lin, Chun-yi, "Current Status of Conservation for Endemic Species in Lanyu," Taiwan Biodiversity Research.
- Xia, Yu-jiu, "Tao Flying Fish Culture and Marine Ecological Conservation," Journal of Taiwan Indigenous Studies.