Biota of Uotsurishima   スペイン語クラス

Uotsurishima's biota is rich in endemicity. Its best-known endemic species is the Senkaku Mole (Mogera uchidai) whose existence is endangered by domestic goats (Capra aegarus) that were intentionally brought to the Island by a private party in 1977.
Four goats (one male, one female and two young) were observed at 1979 (Ikehara and Abe 1980; Shiraishi and Arai 1980). By 1991, about 300 goats were observed on the southern slope of the Uotsuri-jima Island from a ship (Yokota 1998).

Caught between a rock and a hard place...

RED LIST of Threatened Species

The single existing specimen of the Ryukyu mole was captured in 1979, but it was not until 1991 that scientists described it and recognised a number of unique morphological features, in particular characters of the skull and dentition, that distinguished it from other Japanese moles (3) (4). The Ryukyu mole has dark greyish-brown fur, which is paler on the underparts (2), a relatively short tail, and nostrils that are directed outwards (5). Whilst some believe the Ryukyu mole should be placed in its own genus, Nesoscaptor, others believe it is more closely related to Mogera insularis (insular mole) from Taiwan (4), and thus should be called Mogera uchidai (5).

In the same year, the Japanese government finally gave permission to Tatsushiro Koga to develop the islands, although he had already gone ahead and made his workers collect feathers of ahō-dori without official mandate. However, the governmental support only served to spur Tatsushiro's high-flying ambitions. In 1897, he had his workers relocate to Uotsurishima (魚釣島), and in 1898 to Kubashima (久場島), to capture 150,000-160,000 albatrosses, dramatically slashing their population.

Of the terrestrial flora in the Uotsuri-jima Island, some researchers have performed investigation repeatedly. For example, Niiro et al.(1971) recorded 298 species or variations including two endemic species and an endemic variation from the Island, which is mostly covered with subtropical forests dominated by Livistona chinensis var. subglobosa. Furthermore, Niiro and Shinjo (1980) recorded 339 species of 103 families of vascular

The uninhabited island is about four square kilometres and home to 15 native plants and animals, such as the Senkaku mole and the Senkaku-kanaoi, a kind of wild ginger, both of which are on the Japan’s environment ministry’s list of endangered species. There also are about 20 species of rare animals.

The goat population has exploded since a Japanese political group released a pair on Uotsurishima in 1978. According to a 1991 report, about 300 goats were confirmed along slopes on the south side of the island, but the number has now grown to over 1,000.
“Urgent Appeal for the Conservation of Natural Environment in Uotsuri-jima Island in Senkaku Islands, Japan” Yasushi YOKOHATA

At least 34 species of terrestrial birds, seven species of reptiles and no amphibians are known in the Uotsuri-jima Island (Masaki 1941; Takara 1954; Ikehara and Shimojana 1971; Ikehara and Abe 1980; Ota et al. 1993; Ota 1998).

Japanese Goat Problems

Twelve goats were observed on Uotsurishima when the team's vessel circled the islet, and inspectors said damage done by the animals to local flora was easy to see. For example, Ikehara and Shimojana (1971) found 135 species of arthropods, including 63 insects and 41 arachnids, and eight gastropods in this island.

plants from this island. The rate of introduced plants was lowest here (only three species, ca. 1 %) among the four islands in the Senkaku Islands (up to 4.6 %; Niiro et al. 1971). Of all the endemic plants in the Uotsuri-jima Island, two species (Asarum senkakuinsulare, Hypericum senkakuinsulare and Limonium senkakuense) and two variants (Rhododendron simsii var. tawadae and Oplismenus compositus var. purpurascens) have so far been described. Other than these, at least two undescribed endemic variants distribute in this island (Dr. M. Yokota, pers. comm.)

1970: A survey on geology, biota, seabirds, marine life, and insects by a joint team comprised of researchers from Kyushu University and Nagasaki University.

1950 – 1970: Five ecological surveys by Ryukyu University
1968: A survey on subsurface resources, water quality, seabirds, and vegetation by a joint research team comprised of researchers from General Administrative Agency of the Cabinet (Japan), University of Ryukyu, and the Government of Ryukyu.
1969 and 1970: Surveys on marine geology by the first and second academic research teams from General Administrative Agency of the Cabinet (Japan)


Title: The Herpetofauna of the Senkaku Group, Ryukyu Archipelago 
Author: Ota, Hidetoshi; Sakaguchi, Noriaki; Ikehara, Sadao; Hikida, Tsutomu
Date: 1993-07
Publisher: University of Hawaii Press
Citation: Ota H, Sakaguchi N, Ikehara S, Hikida T. 1993. The herpetofauna of the Senkaku Group, Ryukyu Archipelago. Pac Sci 47(3): 248-255.
Abstract: The herpetofauna of the Senkaku Group, western Ryukyus, was reviewed on the basis of recent fieldwork, as well as museum specimens and
literature records. As a result, six species of reptiles were recorded from the islands. They are Gekko hokouensis Pope, Eumeces elegans Boulenger, Scincella sp., Ramphotyphlops braminus (Daudin), Elaphe carinata carinata (Gunther), and Dinodon rufozonatus rufozonatus (Cantor). No amphibian species were recorded. The herpetofauna of the Senkaku Group is distinct from that of other parts of the Ryukyu Archipelago and is more similar to that of Taiwan and eastern continental China. These conclusions conform with paleogeographical evidence indicating that most islands of the Senkaku Group and Taiwan were connected to the eastern margin of the continent during the most recent glacial period, when the remaining Ryukyu Islands were never connected by dry land with the continent.
ISSN: 0030-8870
Goats threatening Uotsurishima environment
OSAKA--Goats overgrazing on grasses and other plants are being blamed for landslides and other environmental destruction that could push indigenous plants and animals to extinction on Uotsurishima island of the Senkaku Islands in Okinawa Prefecture, it was learned Monday. The overpopulation of goats, which eat plants root and all, is thought responsible for the landslides and the...