A rising tide lifts all boats, but in a surprising twist, ascending sea levels launched a flotilla of rafts or canoes on voyages from China to Taiwan around 5,000 years ago, a new study suggests.

At a time when rice farming dominated in other regions, the inundation of the Fuzhou Basin in southeastern China starting about 9,000 years ago led to the creation of a maritime culture that eventually took to the seas, says a team led by archaeologist Barry Rolett of the University of Hawaii in Honolulu.

Analyses of sediment cores extracted from the Fuzhou Basin indicate that, at that time, the kind of marshy areas that are needed for rice paddies disappeared under rising waters. What are hilltops in the region today shrank to islands no more than one mile across.

Locals built outposts on newly minted islands starting around 5,500 years ago and honed their nautical skills, probably using wooden canoes or bamboo rafts to obtain fish and other aquatic food in a vast estuary, Rolett and his colleagues report in the April Quaternary Science Reviews. A largely rice-free, maritime lifestyle eventually enabled sea voyages of 130 kilometers to Taiwan, Rolett proposes. Farming villages first appeared on Taiwan 5,000 years ago.

Rolett’s findings challenge a popular scientific view that a transition to village life in northern China around 8,000 years ago triggered rice-fueled population growth that spread southward. In that scenario, shortages of marshy land suitable for rice paddies motivated sea crossings to Taiwan, possibly originating in the Yangtze Delta just north of the Fuzhou Basin, where researchers have found a 7,700-year-old canoe and three wooden paddles.

“People of the Fuzhou Basin lived on little islands in an estuary that favored maritime activities and seafaring,” Rolett says. “Rice farming was not part of the equation.” Small amounts of rice could have been tended on patches of dry land watered by rain, he holds.

Rolett’s evidence that fishing and seafaring dwarfed rice growing in a submerged section of southeastern China, possibly prompting Taiwan’s colonization, “is quite plausible,” comments archaeologist Robert Bettinger of the University of California, Davis.

Villages from around 5,000 years ago in Fuzhou Basin and on Taiwan contain similar types of pottery, supporting Rolett’s argument, remarks archaeobotanist Dorian Fuller of University College London. Excavations of early Taiwanese villages have yielded millet, a type of grain, as well as some rice. Experienced Fuzhou Basin mariners may have first explored and traded up and down China’s coast, acquiring millet where it grows along the northern coast before taking the grain to Taiwan, Fuller suggests.

Seafaring ignited by ancient flooding of the Fuzhou Basin may have been crucial for colonization of islands beyond Taiwan, Fuller says. Many linguists think that ancestral populations of Austronesian language speakers now inhabiting Southeast Asian and Pacific islands—from the Philippines to Fiji—likely came from Taiwan.

No remains of water craft have been recovered at early villages in southeastern China. Rolett suspects that ancient Fuzhou Basin residents used bamboo rafts much like those still used today to tool around the Min River. Bamboo rafts maintain excellent stability on water even with sails attached, Rolett says.

The notion of people sailing the open ocean thousands of years ago in small boats isn’t new. Some researchers contend that ancient Homo species sailed rafts across the Mediterranean Sea at least 130,000 years ago (SN: 1/30/10, p. 14) and from mainland Asia to Indonesian islands nearly 800,000 years ago (SN: 10/18/03, p. 248).

Rolett’s team analyzed four Fuzhou Basin sediment cores, including two extracted from marshes near a pair of ancient settlements. These villages, located 80 kilometers inland, lie on hills situated on opposite sides of the Min River. Work at these sites has produced artifacts from a Neolithic culture that has been dated to between 5,000 and 4,300 years ago. Investigations at one site indicate that it was occupied by 5,500 yeas ago.

Large amounts of shellfish debris, but only a few grains of rice, have been recovered at these sites. Many archaeologists assume that poor preservation of rice grains obscures extensive Neolithic rice cultivation in the Fuzhou Basin, Rolett says.

Radiocarbon measurements of wood and plant fragments in sediment cores allowed Rolett’s group to estimate when and for how long particular environmental conditions persisted in the Fuzhou Basin.

Peat layers, chemical composition of soil sections and other data indicate that flooding of the Fuzhou Basin began about 9,000 years ago, reached a peak by 7,000 years ago and remained stable until an abrupt sea level decline nearly 2,000 years ago. When Neolithic villagers lived in the basin, their island homes rose about 23 meters above the water’s surface, Rolett estimates.

The amount of grass pollen seen in Fuzhou Basin cores increases dramatically around 2,000 years ago, Rolett adds. Rice pollen is hard to distinguish from other types of grass pollen, but this general trend probably reflects a late shift from maritime pursuits to rice farming, in his view.

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