Surveys Between the end of World War II and 1970, Part 2 (1970, 1971: University of the Ryukyus)

(1) Flora of Uotsuri Island, Kitakojima Island, Minamikojima Island, and Kuba Island (1970, 1971)
An academic survey was conducted by the University of the Ryukyus between September 29 and October 7, 1970, and between March 29 and April 10, 1971, the results of which are summarized in the Senkaku Islands Academic Survey Report. Niiro worked along with Tamaki Shoei, Shinjo Kazuharu, and Miyagi Yasukazu to report in detail on the flora of Minamikojima Island, Kitakojima Island, Uotsuri Island, and Kuba Island.

 

Uotsuri Island: Plant life is plentiful in the mountain range, which rises to an elevation above 300 meters. Interesting plants are distributed near the summits, including Daphne kiusiana Miquel, terihanogiku (Aster taiwanensis), and one species of the Hypericaceae family. The Hypericaceae was a newly identified species, which he named senkaku otogiri (Hypericum senkakuinsulare). Around the middle of the north slope is the most forested region of the island, a virgin forest that includes tabu (Machilus thundergii), benjamin tree, otaniwatari (Asplenium antiquum), shima otaniwatari (Asplenium nidus), ryukyu sekkoku orchids (Eria ovate), and iriomote ran (Trichoglottis ionosma). The area near the summit is very humid due to being frequently shrouded in mist, with plants such as Trichoglottis ionosma, ryukyu sekkoku orchids, mamezuta kazura (Lemmaphyllum microphyllum var. obovatum), kusukusuyokuran (Oberonia anthropophpra var. arisanensis), and uchiwagoke (Crepidomanes minutum) growing as high as 1 meter from the rhizosphere. Niiro notes that the island displays a character unseen elsewhere in the Ryukyu Islands, with 297 species (higher plants, including variants). Uotsuri Island has the most plant resources in the Senkakus, with healthy growth of woody plants and others. There is little human interference, and the environment remains very natural. (Ref. 1)

 

Kuba Island: This island has a mere 87 plant species (higher plants including ferns), with a healthy forest near the volcanic crater that includes osanboku (Pisonia umbellifera), obagi (Macaranga tanarius), benjamin tree, ryukyu gaki (Diospyros maritima), urajiroenoki (Trema orientalis), Machilus thundergii, and Livistona subglobosa. Forest floor plants such as grasses and ferns are scarce. Along with sugarcane and sweet potatoes that grow wild in the crater, there is secondary vegetation including ramie, tsurusoba (Polygonum chinense), and kikeman (Corydalis heterocarpa var. japonica). On the slopes near the middle of the mountain is a grassy field of Japanese dock, hosoba wadan (Crepidiastrum lanceolatum), easter lily, and danchiku (Arundo donax), Niiro reports. This island has seen the most human interference in the Senkaku Islands. (Ref. 1)

 

Minamikojima Island/Kitakojima Island: These islands are weak in flora, with only 51 species (higher plants including ferns) on Minamikojima Island and 24 species (higher plants including ferns) on Kitakojima Island. There is no forest growth, with the only woody plants being benjamin tree, beach naupaka, and monpanoki (Heliotropium foertherianum) seen near the ocean shore. Niiro reports that the main plants on the two islands are hamadaikon (Raphanus sativus var. hortensis f. raphanistroides), hamabossu (Lysimachia mauritiana), Japanese dock, hama mannengusa (Sedum formosanum), kinuge mehishiba (Digitaria sericea), nogetainubie (Echinochloa oryzoides), kikeman (Corydalis heterocarpa var. japonica), and ohamaguruma (Wedelia robusta). (Ref. 1)

He indicates that overall, species common with Taiwan Island are the most prevalent, implying that the islands are closely linked. By calculating the rate of naturalization (1.8%) among vascular plant species (327 species), he demonstrates that the natural state has been well preserved, and that the plant life of these islands is close to its natural state, with Uotsuri Island's rate (1%) being of particular note. (Ref. 1)

 

(2) Land animals of Uotsuri Island, Kitakojima Island, Minamikojima Island, and Kuba Island (1971) Ikehara Sadao (University of the Ryukyus Faculty of Science and Engineering) and Shimojana Matsuei (Ryukyu Governmental Futenma High School) reported the results of their 1971 survey of land animals found on Uotsuri Island, Kitakojima Island, Minamikojima Island, and Kuba Island in the aforementioned 1971 University of the Ryukyus Senkaku Islands Academic Survey Report. In particular, they observed a total of 12 short-tailed albatrosses on Minamikojima Island, which was the first time in 71 years since Miyajima's 1900 report observed the birds residing on the island. (Ref. 2)

In this survey 126 families and 260 species of land animal were observed, with the majority of those being newly identified. Almost all of the invertebrates observed on Kuba Island were newly recorded species. Two species of mammal were identified, black rats and cats, both believed to have been transplanted by humans. Land birds were plentiful on Uotsuri Island (although there were few species), and the main habitats for sea birds were Minamikojima Island, Kitakojima Island, and Kuba Island. On Kuba Island a pronounced phenomena of habitat separation between the brown booby and the streaked shearwater was observed. No amphibians were observed, and the king ratsnake was the only snake recorded, residing on Minamikojima Island, Kitakojima Island, and Uotsuri Island. A total of 56 families and 102 species of insect were collected, with beetles and moths most common. This was thought to be due to their higher survivability in typhoons. Arachnids (all newly recorded), myriapods (11 families, 17 species), and land snails (6 families, 10 species) were also observed. Ikehara and Shimojana concluded by saying that the fauna of the Senkaku Islands were strongly affected by factors including the islands' land area, geographic proximity, geology and soil, water volume and quality, vegetation, and human action. (Ref. 2)

 

(3) Coastal invertebrates of Uotsuri Island, Kitakojima Island, and Minamikojima Island (1971) Nakasone Yukio (University of the Ryukyus Faculty of Liberal Arts) and Nagahama Katsushige (University of the Ryukyus Faculty of Education) reported the results of their 1971 survey of coastal invertebrates in the 1971 University of the Ryukyus Senkaku Islands Academic Survey Report. In the survey they observed 141 species; since there had been almost no prior survey of coastal invertebrates in the Senkakus, they were almost all newly recorded. However, there were no particular newly observed organisms for the Ryukyu Islands, with the overall fauna quite similar to that of Okinawa Island, Amamioshima Island, and the Ogasawara Islands. The survey catalog lists: I. Porifera phyla (Haliclona cinerea and three other species), II. Coelenterate phyla (Solanderia secunda and 19 other species), III. Mollusca phyla (Rhyssoplax kurodai and 67 other species), IV. Arthropod phyla (Capitulum mitella and 37 other species), and V. Echinoderm phyla (acanthaster planci and 15 other species). (Ref. 3)

 

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Ref.1 :Niiro Yoshima, Tamaki Shoei, Shinjo Kazuharu, and Miyagi Yasukazu, "Senkaku Retto no shokubutsu" (Flora of the Senkaku Islands), in Senkaku Retto gakujutsu chosa hokoku (The Senkaku Islands Academic Survey Report) (Okinawa: University of the Ryukyus, July 1971), p. 37.

Ref.2 :Ikehara Sadao and Shimojana Matsuei, "Senkaku Retto no rikusei shokubutsu" (Land Animals of the Senkaku Islands), in Senkaku Retto gakujutsu chosa hokoku (Senkaku Islands Academic Survey Report) (Okinawa: University of the Ryukyus, July 1971), p. 85.

Ref.3 :Nakasone Yukio and Nagahama Katsushige, "Senkaku Retto no kaigan musekitsui dobutsu" (Coastal Invertebrates of the Senkaku Islands), in Senkaku Retto gakujutsu chosa hokoku (The Senkaku Islands Academic Survey Report) (Okinawa: University of the Ryukyus, July 1971), p. 115.

 

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