Kawai, K., Terada, R. and Kuwahara, S. (eds): The Islands of Kagoshima University Research Center for the Pacific Islands, 15 March 2013

Chapter 22 Biodiversity in the Islands of Kagoshima Takahiro OKANO

1. Introduction ference in temperature. The average temperature he plane leaves from Kagoshima Airport head- in Isa City (average value from 1981 to 2010, the Ting south, with Mt. Sakura-jima smoldering same shall apply hereinafter) is 15.3 ˚C, 18.6 ˚C below. Is. comes into view. Also known in Kagoshima City, 21.6 ˚C in Amami City Naze, as a “Floating Alps,” the mountains of Yakushima and 22.4 ˚C in Okinoerabujima Is. Furthermore, the Is. rise almost 2,000 m out of the ocean surrounded annual average temperature of Is. to the by the Kuroshio Current. Yakushima Is. is a world south was 22.8 ˚C from 2001 to 2010. The tempera- heritage site famous for its Japanese cedar, some of ture difference of lowland north to south is 7 ˚C, which are more than 1,000 years old. To the side, and is classified as warm-temperate and subtropical long and flat Tanegashima Is., with its rocket base, climate zones. can be seen. While gazing at the chain of Tokara The highest mountain of , as Islands, the plane begins to descend. Welcomed by well as all of Kyushu, is Mt. Miyauranodake (1,936 m). coral reefs, white sandy beaches, and the beautiful Also in mainland Kyushu, Mt. Karakunidake of blue ocean, the plane lands in Amami-Oshima Is. Kirishima mountains soars 1,700 m high. As eleva- As you get off the plane, you notice the difference tion increases, temperature decreases. In winter, air in temperature. Depending on the season, there can temperature near the mountain top drops below zero even be a 10 ˚C difference. Amami-Oshima Is. is and snow can be seen, and the area belongs to the a semitropical island. Even the appearance of its cool-temperature zone. forest differs from that of mainland Kyushu. In the Due to the world's largest warm current, dense subtropical evergreen forests of the Amami Kuroshio, rainfall in Kagoshima Prefecture is abun- Islands, many plants and are found which dant. Rainfall is especially heavy during the rainy do not exist anywhere else on earth, such as the en- and typhoon seasons. Average rainfall in Isa City demic Amami rabbit. (average value from 1981 to 2010, the same shall Kagoshima Prefecture, with its chain of unique apply hereinafter) is 2,057 mm, 2,265.7 mm in islands stretched out 600 km north to south, is a Kagoshima City, 2,837.7 mm in Amami City Naze, prefecture rich in biodiversity. This biodiversity is 1,836 mm in Okinoerabujima Is., and 1,740.9 mm supported by the wide diversity of the environment. in Yoronjima Is. Especially Yakushima Is. is known This article introduces the characteristics of the var- for its abundant rain. Average rainfall in the seaside ious environments and their biodiversity, and major areas is 4,477.2 mm, and 8,000-10,000 mm falls in of the islands. the mountainous areas.

2. Environmental diversity 2.2. Two biogeographic areas 2.1. Three climate zones and abundant rainfall Kagoshima Prefecture stretches across two biogeo- eographically, Kagoshima Prefecture stretch- graphic areas, reflecting long north to south- geo Ges over 600 km north to south, with a latitude graphic characteristics, and island formations of the width of five degrees, from Shishijima Is. rising Ryukyu arc from southern Kyushu to . from Yatsushiro Bay at 32˚ N to Yoronjima at 27˚ A biogeographic area divides the earth into N. This difference in latitude is reflected in the dif- geographical distribution patterns of plants and

136 The Islands of Kagoshima animals. Geographical distribution is determined by animals is assumed to have been blocked, and thus terrain which blocks migration, such as an ocean or formed a border line. For instance, Habu, a poison- mountain chain, history of connection and separa- ous , does not live north of the Tokara Straits. tion of the continent and island, etc. Based on this, Looking at the seafloor topography of the the earth is largely divided to six zoogeographic Ryukyu arc, there is another 1,000 m + deep trench. provinces and six floristic kingdoms. Kagoshima This is the Kerama Straits, located south of the Prefecture is classified in the Palearctic and Oriental Kerama Islands. This is also a borderline for land an- zoogeographic provinces and in the Boreal and imals. Regarding Habu , Habu are distributed Paleotropical floristic kingdoms. Kagoshima Pre- north of the Kerama Strait, but the Sakishima habu fecture is the only prefecture in which is in- is distributed south of Kerama Strait. Hence, when cluded in two geographical regions. considering biodiversity of the , the The border line between the Palearctic region area north of the Tokara Strait is referred to as North and the Oriental region for land animals such as Ryukyu, and the area between the Tokara Straits and mammals, terrestrial , and amphibians, is the the Kerama Straits as Middle Ryukyu, and the area Tokara Straits located between Is. and south of Kerama Straits as South Ryukyu. Is. of the . This border In contrast, the straits between Yakushima Is. and line is called the “Watase line” (Fig. 1). mainland Kyushu, as well as between Tanegashima During the glacial period, water was stored in Is. and mainland Kyushu, are no deeper than 100 m. the continental glaciers as the earth cooled, and Consequently, these areas are assumed to have been ocean water levels are estimated to be more than connected to mainland Kyushu with the 120-140 m 100 m lower. However, the Tokara Straits still ex- drop in sea level during the latest glacial period about isted as water straits because the water depth was 20,000 years ago, allowing land animals such as more than 1,000 m. As a result, migration of land deer and monkeys macaques migrated freely be-

Fig. 1. Map of the island-chain of Kagoshima and Okinawa Prefectures, southern Japan, showing Satsunan and Ryukyu Islands.

137 Kagoshima University Research Center for the Pacific Islands tween. As a result, the biota of Yakushima Is. is very 3. Characteristics of biodiversity in Kago- close to that of mainland Japan, including Kyushu. shima Prefecture Yakushima Is. is the southern limit of the distribu- 3.1. Various forest types tion of the Japanese macaque. lants have optimal conditions and limit values Distribution of flora has consistently changed Pin which to survive, and the areas in which they due to the influence of the Kuroshio Current which live are limited by temperature, sunlight, and arid- flows northward. The Satsunan Islands are a transi- ity. Since Kagoshima Prefecture has abundant rain- tional zone between the Holarctic floristic kingdom fall, forests have developed to adapt to three climate and the Paleotropical floristic kingdom. zones. An evergreen broadleaf forest developed on 2.3. 605 Islands Osumi Peninsula, which is a warm-temperate zone. Kagoshima Prefecture has 605 islands, second only This kind of forest is mainly comprised of evergreen to Nagasaki Prefecture. However, according to the broad leaf trees, such as white oak, Chinquapin total area of the isolated islands is about 2,500 km2, (Castanopsis), laurels such as Japanese machilus and Kagoshima is the largest. camphor trees, theaceaes such as “Sakaki” (Cleyera Island structure also varies. Some islands were japonica) and . This type of forest is also formed as the continent tore apart due to crustal called a “glossy leaved forest” because the plants movement. Others were formed volcanic eruption, have small, thick leaves which can withstand cold elevated coral reefs, or elevated seabed sediment on and dry conditions, and the surface cuticle layer of the seabed. Still others were formed by the elevated the leaves reflects the sunlight. Amami-Oshima and rocks. The environments of the islands also greatly Is., which belong to the subtropical vary depending on the constitution of the islands. zone, have subtropical evergreen broadleaf forests Furthermore, because of the many islands, the comprised of Chinquapin (Castanopsis siebol- total extension of the coastline is 2,643 km, and dii known colloquially as “Sudajii”), “Okinawa- is the third longest of all the prefectures in Japan. urajirogashi” (Quercus miyagii), Japanese machi- Coastlines also vary between rock reef, coral reef, lus, Distylium racemosum. For a humid forest to pebble beach, sandy beach, and tidelands. Within develop at this latitude is unusual in the world. the sandy beaches, the sandy beaches on Yakushima The high elevations of Kirishima Mountains Is. are comprised of shaved granite and those on and Takakuma Mountains are cool-temperature Yoronjima Is. by the coral pieces. Large-scale zones of summer-green forests consisting of de- mangrove forests are established at the mouth of ciduous broadleaf trees. Takakuma Mountains is the Sumiyou River on the Amami-Oshima Is. southernmost limit for Japanese beech and Japanese oak, which are the dominant species of the cool- 2.4. Complex topography temperate zone. Kagoshima Prefecture is one of the prefectures which have many volcanoes in Japan. There are 3.2. Rich diversity of species four massive calderas, Kakutou, Aira, Ata, and Because Kagoshima Prefecture has three climate Kikai, and 11 active volcanoes. The activities of the zones and two zoological regions, Kagoshima earth have created a complex topography, and vari- Prefecture has a rich diversity of species, including ous environments. The activities of active volcanoes 49 mammals, 419 , 48 reptiles, and 26 amphib- have influenced the creatures living nearby, at times ians. Moreover, more than 1,000 land, fresh water, have greatly reforming the topography, and disrupt- brackish water snail, 200 brackish and fresh water ing the biota. fish, approx. 15,000 insects, approx. 3,100- vascu Ryukyu Archipelago, which includes the lar plants are estimated to be distributed in the area Osumi, Tokara and , is a typical is- (Table 1). 25-60 % of all species in Japan land arc-trench system as the result of the rise and can be found in Kagoshima. When considering that fall of the earth’s plates along the ocean trench. the size of Kagoshima Prefecture is only 2.4 % of all

138 The Islands of Kagoshima of Japan, the diversity of species is clearly rich. once belonged to one species, become isolated on Supported by complex ocean currents center- various islands which have been separated due ing on the Kuroshio Current and land stretch- to a rise in sea level, etc., the species differenti- ing north and south, the diversity of marine fish ate into endemic species and subspecies on each fauna in Kagoshima Prefecture is high. Although island. Otton frogs which live in Amami-Oshima the whole image is still not fully understood as an and Kakeromajima Is. and Holst’s frogs which are exhaustive survey of fish has just begun, future distributed throughout the Okinawa Islands can be confirmation of approx. 2,500 species are- esti considered as examples. mated, and this is thought to be the highest num- Another case is where a species used to be ber of fish species in Japan (Motomura 2012). widely distributed, but due to some reason, such as competition with another species or change in the 3.3. Many endemic species environment, generally became extinct, yet sur- When distribution of a plant or animal is limited vived on a certain island. This condition is called to a specific area, it is called an "endemic" species. a “relict” species. The Amami rabbit, distributed Islands surrounded by ocean water have a higher only on Amami-Oshima and Tokunoshima Is., is a rate plant and animal endemism, because migra- prime example. The Amami rabbit is estimated to tion and interaction with other areas are blocked. have diverged from the Leporidae group in the mid- In Kagoshima Prefecture, the endemic species have Miocene period (about 10 million years ago), and is diversely evolved due to the existence of various is- called a "living fossil" because it has no existing re- lands of different constitutions. lated species, and has remained in its primitive form. There are some different processes which cre- When compared with other Leporidae species, the ate endemic species. One case is where each island forelegs, hind legs and ears are shorter, and it can- has a unique environment and species develop their not jump high like most rabbits. This species used to individual evolutionary history. As species, which be widely distributed throughout the continent, but

Table 1. Number of native species in Kagoshima Prefecture Number of threatened Number of native species (CR, EN, VU) in Number of native species in Kagoshima Kagoshima Prefecture species in Japan (A) Prefecture (B) B/A (%) (C) Manmals About 180 49 25.0 12 Birds 680 419 61.6 42 Reptiles 96 48 45.8 11 Amphibians 65 26 40.0 7 Brackish- and Fresh-water fishes About 400 200 + 50.0 43 Insects About 30,000 About 15,000 46.9 35 Land, Fresh- and Brackish-water snails About 1,100 1,000 + 90.9 103 Brackish- and Fresh-water decapods 197 70 35.5 3 Fishes About 4,000 About 2,500 62.5 Vascular plants About 7,000 About 3,100 44.3 512 souce: Kagoshima Prefecture (2012). (A) is number of native species for evaluation in the Red List of the Ministry of the Environment (2006, 2007), (B) is number of native species for evaluation in the Red Data Book of Kagoshima Prefecture (2003), exclude Reptiles, Amphibians, Fishes and Vascular plants. Regarding Reptiles and Amphibians, the source is the list of Japanese names of Reptiles and Amphibians in Japan made by the Herpetological Society of Japan (27/08/2012 draft). Regarding Fishes, the source is Motomura (2012). (C) is base on the Red List of the Ministry of the Environment. Regarding Reptiles and Amphibians, base on edition in 2012. Regarding Vascular plantsfrom, base on edition in 2000. The other is base on edition in 2006 and 2007.

139 Kagoshima University Research Center for the Pacific Islands went extinct for some reason, such as competition of Japanese macaques. Yakushima Is. is the southern with other Leporidae or other animals, or a change limit of reptiles such as Japanese ratsnakes and Tiger in the environment. However, they are thought to keelbacks, and Amami-Oshima Is. is the northern have been able to survive on Amami-Oshima and limit of Habu snakes and Hime habu. Regarding Tokunoshima Is. because these islands were sepa- amphibians, southern Kyushu is the southern lim- rated from the continent since ancient times and no it for Tago's Brown frogs and Kajika frogs, and competing animals were introduced to the islands. Yakushima is the southern limit for Japanese Tree frogs. Is. is the northern limit for 3.4. Northern and southern limits Ryukyu Kajika frogs, and Amami-Oshima Is. is the Kagoshima Prefecture is elongated north to south, northern limit of Hallowell’s Tree frogs (Kagoshima and includes the boundary between biogeographic Environmental Studies Workshop 2009). areas. As a result, Kagoshima Prefecture is the Kagoshima Prefecture is influenced by the northern or southern limit of distribution for many warm Kuroshio Current, and is the northern limit plants and animals have. of the global distribution of coral reefs. The area The distribution boundary of organism to the of Japan with coral communities is divided into north is called the northern limit. For southern or- two regions based on the sea surface temperature ganism with a center of distribution in warmer ar- in the coldest month, 18 ˚C, which is considered eas, the northern distribution limit is determined by to be needed for coral reef formation. It is region restrictive characteristics such as the temperature in where coral reefs form and region where reefs rarely the northern hemisphere. The opposite is the south- formed, although coral communities are distributed. ern limit, where the distribution of northern organ- This boundary is between the Osumi peninsula and ism with a center of distribution in colder areas is Tanegashima Is. determined by the restrictive characteristics of a 151 hermatypic coral species have been con- higher temperature, stronger sunlight, and aridity. In firmed in the sea around Tanegashima Is. The addition, the northern and southern limits may also composition of coral species in Tanegashima Is. is be determined by obstacles in establishment due to significantly different from that in Amami-Oshima competition with other organism or blockage of mi- Ia. Southward along the Tokara Strait, the number gration due to a water strait, etc (Miyamoto 2010). of species greatly increases. In the sea around the Regarding plants, as Kagoshima Prefecture Amami Islands, about 220 species of hermatypic stretches between the subtropical and warm- corals have been confirmed. temperate zones, there are many cases where Development of coral reef is rarely seen in Kagoshima is the northern limit for southern plants Nagashima and Shishijima Is. in northern part of which are mainly distributed in the tropical zone, Kagoshima Prefecture, but many hermatypic coral and the southern limit for northern plants which are have been confirmed. Coral communities have also mainly distributed in cool-temperature and warm- been confirmed in the sea around Koshikijima Is., temperature zones. Yakushima Is. is the southern Sakurajima, and Satamisaki, with 17 species in the limit for more than 200 plants, and the northern sea around Sakurajima and 23 species in the sea limit for more than a few plants (Ministry of the around Satamisaki (Ministry of the Environment Environment et al. 2012). While Amami Islands is and Japanese Coral Reef Society 2004). the southern limit for 97 plants, it is also the northern limit for 239 plants (Kagoshima University 2012). 3.5. Endangered species Water straits are a boundary which hinders land There are many endangered species in Kagoshima. animal migration. mainland Kyushu is the southern Reasons for this include human-caused effects such limit for mammals such as raccoon dogs, Japanese as forest development and logging, ocean and river weasels, and Japanese martens. Yakushima Is. ma- development, negative changes in the environ- caques, a subspecies of Japanese macaques, are dis- ment due to the reduction of human conservation tributed on Yakushima, which is the southern limit activities, as well as factors such as many endemic

140 The Islands of Kagoshima species with small populations living in a limited Kaiike, and Namakoike, which are closed off by this distribution. Furthermore, there may be cases where barrier beach, are brackish lakes whose water level species have gone extinct in other places, but some- and quality are affected by the ocean. Chromatiales how remain in Kagoshima. (purple sulfur bacteria), a type of fossil microbe, live Many species listed in the Red List of the in Kaiike. Ministry of the Environment, are distributed in “Ubamegashi” oakforests (Quercus phillyrae- Kagoshima Prefecture (Table 1). In particular, spe- oides), which are wind beaten scrub forests, grow cies which are distributed in island areas such as the along the cliffs in the steep seacoast zone, and clus- Amami Islands and Yakushima Is., are listed as the ters mainly of Rhaphiolepis umbellate, Japanese endangered species. Pittosporum (Pittosporum tobira) and Eurya Kagoshima Prefecture published a prefec- emerginata can also be seen. Large spiny tree ferns tural Red Data Book edition in 2003. Kagoshima grow naturally in the valley, and this is the Prefecture has many islands, and the status of a spe- northern limit of the tree ferns and has been desig- cies varies on each island, even within same species. nated as a Natural Monument. Moreover, Japanese Consequently, from the standpoint of preserving lily (Lilium speciosum) grows among the Japanese genetic diversity, original classification terms such pampas grass “Susuki” (Miscanthus) in the mead- as “Vanished,” “Vanish endangered Category I/II,” ows and plains. “Semi-vanished endangere” in “local population.” Mammals such as the Japanese weasel (Mustela 4,467 plant and animal species have been specifi- itatsi) and Kyushu hare (Lepus brachyurus brachy- cally included (Table 2). urus) are present as well as birds, such as the east- ern reef heron (Egretta sacra), Japanese pheasant 4. Biodiversity of islands in Kagoshima (Phasianus versicolor), tit, grey wagtail (Motacilla 4.1. Koshikijima Is. cinerea), Japanese wood pigeon ( jan- oshikijima Is. is located in the East Sea, thina; Natural Monument). In addition many birds Kabout 40 km west of Satsuma peninsula, and is such as the yellow wagtail (Motacilla flava), yellow part of a group of isolated islands including habited breasted bunting (Emberiza aureola), and black- islands Kami-Koshikijima, Naka-Koshikijima, and capped kingfisher Halcyon ( pileata) pass through Shimo-Koshikijima Is., and other surrounding small during their spring and fall migrations, making islands. Since the islands were connected to main- this area an important stopover for migratory birds. land Kyushu during the glacial stage, the biota is Furthermore, black-tailed gulls (Larus crassirostris) close to that of mainland Kyushu. nest on the Kashima cliffs in Shimo-Koshikijima Is., On the northeast coast of Kami-Koshikijima Is., and this is the southern limit of their breeding area. there is a 4 km of barrier beach called “Nagame no Hama” and offers a beautiful lanscape. Kuwasakiike,

Table 2. Number of threatened Species included in the Red Data Book of Kagoshima Prefecture (2003) Important on Extinct in the Threatened: Threatened: Near distributive Data Extinct Wild Endangered Vulnerable Threatened characteristics Deficient Subtotal Manmals 3 0 10 8 3 18 4 46 Birds 0 0 17 24 15 8 14 78 Reptiles 0 0 2 3 9 21 3 38 Brackish-Amphibians and Fresh-water 0 0 2 6 4 13 0 25 fishes 0 0 19 5 8 79 21 132 Insects 0 0 28 35 52 1,110 24 1,249 Land, Fresh- and Brackish-water snails 8 0 65 74 193 38 89 467 Brackish- and Fresh-water decapods 0 0 7 4 19 38 3 71 Vascular plants 5 3 490 423 756 590 94 2,361 Total 16 3 640 582 1,059 1,915 252 4,467

141 Kagoshima University Research Center for the Pacific Islands

4.2. Yakushima Is. in other areas in Japan. However, trees living more Yakushima Is. is an almost completely round island than 1,000 years are not uncommon in Yakushima with a circumference of 130 km, and is located 60 Is. Because, Yakushima Is. has abundant rain and km off the southern tip of mainland Kyushu. There high humidity, natural Japanese cedar grows very are 11 mountains higher than 1,500 m, including slowly, and does not rot easily due to its high resin Mt. Miyanouradake (1,936 m), the highest moun- content and tight rings. In Yakushima Is, natural tain in Kyushu. Japanese cedar trees older than 1,000 years old The biota is close to mainland Kyushu, since are called as “Yakusugi,” and trees less than 1,000 it used to be connected to mainland Kyushu until years old are called as “Kosugi.” Virgin and natu- about 20,000 years ago, but Yakushima’s primitive ral forests with Yakusugi trees over 3,000 years old natural environment was prone to change and pro- provide a unique and beautiful scenery. The vertical duced a unique ecological system in Yakushima Is., distribution of vegetation, and the beautiful scenery where endemic species and subspecies can be seen. of virgin forests which includes Yakusugi, are rea- Yakushima Is. was inscribed on the World Heritage sons why Yakushima Is. has been inscribed on the List as a natural property in 1993. World Heritage List. Subtropical to cool-temperate forests can be Added to the more than 1,900 species of flo- seen in Yakushima Is. Subtropical flora such as ra, there are 600 species of moss. Yakushima Is. superba and Chinese banyan (Ficus microcar- is the southern limit for more than 200 species of pa) grow along the coast, which belongs to the sub- plants, such as Japanese fir Abies( firma), Southern tropical zone. Warm-temperature zone broad-leaved Japanese hemlock (Tsuga sieboldii), and Japanese evergreen forests have developed from the coastline cedar, and is the northern limit for many species, to nearly 700-800 m along the warm-temperature such as Caesalpinia crista, “Oni hinoki shida” zone mountainsides, and warm-temperature zone (Asplenium x kenzoi). Many endemic and endan- conifer forests comprised of Japanese cedar “Sugi” gered species have been confirmed, such as spe- (Cryptomeria japonica) grow at elevations from cies which are restricted to the highlands, and spe- around 700-800 m to 1,200 m. At elevations ap- cies which grow in specific environments such as proaching 1,200-1,800 m in the cool-temperature rocky areas and mountain streams (Ministry of the zone, there are cool-temperate conifer forests and Environment et al. 2012). 16 species of mammals, above that, scrub forests of Yakushima dwarf bam- including four endemic subspecies, Yakusika deer boo (Pseudosasa owatarii) and Yakushima rho- (Cervus nippon yakushimae), Yakushima macaque dodendron (Rhododendron yakushimanum) at the (Macaca fuscata yakui), Yakushima Dsinezumi mountain summit. At the southern edge of Japan shrew (Crocidura dsinezumi umbrina), and near elevations of 1,600 m in cool-temperature Yakushima small Japanese field mouse Apodemus( zone, there are high moors comprised of peat moss, argenteus yakui), have been confirmed. 167 spe- “Yakushima-koke-sumire” (Viola verecunda var. cies of birds, including two endemic subspecies, yakusimana), etc. On the other hand, all the climates Garrulus glandarius orill and Parus varius yakushi- of the Japanese islands, from Hokkaido to Kyushu mensis, have confirmed, and four species, Ryukyu are condensed on this one island, however, represen- robin (Erithacus komadori), Japanese wood pigeon, tative tree species of the cool-temperature zone on Izu Leaf-warbler (Phylloscopus ijimae), and Izu the mainland such as Japanese beech, “Mizunara” Thrush (Turdus celaenops) have been designated as (Quercus crispula blume), etc., are noticeably miss- Natural Monument. In addition to these, 15 species ing. The distribution of plants according elevations of reptiles, 8 species of amphibians, and approxi- such as this is called “vertical distribution of vegeta- mately 1,900 insects species have been confirmed, tion.” Yakushima Is. has an extremely abundant biota for Natural Japanese cedar is distributed from ele- an island with such small dimensions. vations between about 600-1,800 m in the center of On the northwestern side of the island in Nagata, the island. Those trees usually live up to 800 years Maehama, Inaka-hama, Yotsuse-hama are beautiful

142 The Islands of Kagoshima white beaches comprised of shaved granite sand. Grass lizards “Aokanahebi” (Takydromus sma- Every year, Loggerhead Sea Turtles come to nest ragdinus) and Ryukyu green snakes (Cycophiops on these beaches. As these beaches have the highest semicarinatus). In contrast, Is. is number of nesting in the north Pacific region, it is the southern limit for the Japanese Grass Lizard a crucial habitat in the lifecycle of the turtle. The (Takydromus tachydromoides) which is distributed three beaches, collectively called “Nagatahama,” from Hokkaido to Kyushu. However, there are cases have been designated as protected wetlands under of species expanding their distribution to north from the Ramsar Convention. the Tokara strait, while others are expanding south Loggerhead sea turtles mainly visit Nagata- from Tokara strait, such as Hokou gecko (Gekko hama to lay eggs from May to July. It takes a female hokouensis). Takara gecko (Gekko shibatai) is en- about 30 minutes to dig a hole and lay 60-100 eggs. demic species in and Kodakarajima Is. Every year, 2,000-3,000 turtles arrive on the beach Regarding amphibians, Ryukyu Kajika frogs to lay eggs. (Buergeria japonica), are widely distributed south A comprehensive survey of the fish of Yakushima from the Tokara Straits, and Kuchinoshima Is. is its Is. was carried out in 2008-2009, by ten agencies in northern limit. Japan, including Kagoshima University Museum In consideration of mammals, wild cattle in and National Museum of Nature and Science. As a Kuchinoshima Is. are considered to be an ancient result, 24 orders, 112 families, 382 , and 951 Japanese native species, Tokara goats (Capra species of marine (including brackish water) fish hircus domestic) were widely distributed from the were recorded, and various fish could be confirmed Ryukyu Archipelago to Indonesia. Erabu flying fox (Motomura and Matsuura 2010). (Pteropus dasymallusdasymallus) which lives on and Takarajima Is., has been desig- 4.3. Tokara Islands nated as Natural Monument. Nakanoshima Is. is Tokara Islands are a transitional zone between the also the grazing land for Tokara ponies (Equus ca- warm-temperature and the subtropical zones, and ballus). are located on the boundary of two biogeographic ar- 116 species (and subspecies) of birds have eas. As a result, the islands are the northern or south- been confirmed, including the Izu Thrush, Izu ern limit for many plants and animals. Moreover, Leaf-warbler, and Ryukyu robin. Moreover, Tokara many endemic species which have evolved as the Islands are a point of passage for migratory birds, islands became isolated can be seen. and many kinds of birds can be seen in during the Most of the islands belong to a volcanic spring and fall migration seasons. zone. There are volcanos such as Mt. Otake of Various species of insects, such as Dicerca Nakanoshima Is., called Tokara-Fuji, and Mt. Otake nishidai beetle, flat-headed wood-borer, and of Suwanosejima Is. which is active even today. Hemicordulia mindana nipponica dragonfly, have The islands from Kuchinoshima to Akusekijima Is. been confirmed. have the characteristic landscape of a volcanic is- Regarding plants, groves of Pandanus odora- land, surrounded by extremely high and low cliffs, tissimus are found in Kuchinoshima Is. the pine’s as well as gushing hot springs, considered to be northern limit, and clusters of Rhododenron tamu- one of the blessings from volcanoes, as places of rae Masam can be seen in the volcano wilderness of recreation and relaxation for people on the island. Nakanoshima and Suwanosejima Is. Suwanosejima Kodakarajima and Takarajima are islands of raised Is. is the southern limit for Japanese Green Alders limestone, with many flatlands and coral reefs sur- (Alnus viridis) and Takajima Is. is the northern limit rounding them. for clusters of Heliotropium foertherianum. The “Tokara-Habu” (Protobothrops tokarensis) is endemic to Takarajima and Kodakarajima Is., and 4.4. Amami Islands Kodakarajima Is. is northern limit of distribution for Amami Islands are characterized by subtropical ev- Habu (Protobothrops) snakes, as well as for Green ergreen broadleaf forest and many endemic species.

143 Kagoshima University Research Center for the Pacific Islands

The forests on Amami-Oshima and Tokuno- Islands are the many endemic species, especially shima Is. are green all year round. Following the relict species. This is because the Middle Ryukyu same latitude across the globe, there are many arid islands including the Amami Islands have a longer regions, such as Mexico on the American continent history of isolation from the continent, since at least and the Sahara desert on the African continent. This the early Pleistocene of the Quaternary Era (about 2 fact shows how rare the humid forests across the million years ago until about 1.7 million years ago). Amami Islands are. The moist climate with abundant Such relict species are generally character- rain has produced a subtropical evergreen broadleaf ized by prominent geographical and genetic gaps forest consisting of trees of the Castanopsis group from extant sister populations outside the Middle and white oak. Ferns are also abundant, including Ryukyu. Prominent faunal representatives of such the Flying Spider-monkey Tree Fern (Cyathea lep- relict endemisms are the Amami rabbit (Pentalagus ifera) which reaches heights exceeding 10 m. Plants furnessi), Ryukyu long-furred rat (Diplothrix lega- also grow on the fronds and trunk of the tree. Plants ta), three spiny rat species of the genus (two spe- whose roots grow in the tops of trees or on rocks, cies are distributed on the Amami Islands), Lidth’s instead of in the ground are called “epiphytes,” and jay (Garrulus lidthi), Kuroiwa’s grounded gecko a humid forest is also a reservoir of epiphytes. 1,334 (Goniurosaurus kuroiwae splendens, a subspecies species of vascular plant have confirmed in Amami- distributed on Tokunoshima Is.), and Anderson’s Oshima Is., 68 species are endemic (Kagoshima crocodile newt (Echinotriton andersoni). Floral University 2012). representatives are Arisaema heterocephalum, Viola Islands of the Ryukyu Archipelago, including amamiana, and Polystichum obae. The Amami Amami-Oshima Is., were originally continental is- Islands are an “Ark” of terrestrial plants and animals lands connected to the Eurasian continent. The pres- from an ancient continent. ent configuration of the islands is considered to have 14 species of land mammals, including four en- been formed mostly through the initial formation demic species, namely the Amami rabbit, Amami and expansion of the Okinawa Trough and through spiny rat, Tokunoshima spiny rat, and Orii’s other radical tectonic movements since about 15 shrew, have been confirmed. The Watase’s Shrew million years ago, changes in the sea level caused (Crocidura watasei) and Ryukyu long-furred rat, by climate change since about 1.7 million years ago, which are also distributed throughout the Okinawan and sedimentation of the Ryukyu Limestone associ- islands, are endemic to Middle Ryukyu. 18 spe- ated with the development of coral reefs. (Kimura cies of land reptiles, including two endemic spe- 1996, Kizaki and Ooshiro 1980, Kizaki 1997, Ota cies, namely Banded ground gecko (Goniurosaurus et al. 2001). kuroiwae splendens) and Hyan coral snake The biota of the island reflects the history of the (Sinomicrurus japonicus japonicus), have been island. When the area was separated from the con- confirmed. The Okinawan tree lizard Japalura( po- tinent, it became an island with the terrestrial plants lygonata polygonata), Barbour's blue-tailed skink and animals of that time. As time passed, the plants (Plestiodon barbouri), Amami odd-scaled snake and animals began to follow an original evolution- (Achalinus werneri), Hai coral snake (Sinomicrurus ary path. The island further divided into smaller japonicus boettgeri), Habu (Protobothrops flavo- islands, and the plants and animals diverged into viridis), and Himehabu ( okinavensis) are different species on each island. Furthermore, the endemic to Middle Ryukyu. 12 species of amphib- repeated rise and fall of the sea level due to climate ians have been confirmed, including four endemic change, which became especially significant since species, namely Amami Red Tree Frog, Amami about 1.7 million years ago, resulted in the repeated Tip-nosed Frog (Odorrana amamiensis), Amami separation and connection between neighboring is- Ishikawa Frog (Odorrana splendida), and the Otton lands, and in turn, the continuous isolation and in- Frog (Rana subaspera), and a subspecies of the teraction of plants and animals. Amami Green Tree Frog (Rhacophorus viridis ama- Characteristics of the biota in the Amami miensis). The Sword-Tailed Newt (Cynops ensicau-

144 The Islands of Kagoshima da) and Anderson’s Crocodile Newt are endemic to experience the rich biodiversity of Kagoshima. It Middle Ryukyu. 226 species of land, fresh water, will surely teach us the mysteries of life. and brackish water snails have also been confirmed (Kagoshima University 2012). References 269 species (and subspecies) of birds have been Kagoshima Environmental Studies Workshop (ed.) 2009. 100 Environmental Keywords in Kagoshima Prefecture. 245 confirmed, Lidth’s jay is endemic to the Amami pp., Nanpoushinsha, Kagoshima. (in Japanese) Islands and the Amami woodcock to the Middle Kagoshima Prefecture 2003. Kagoshima Red Data Book. 642 Ryukyu. Lidth's jay, Amami thrush (Zoothera dau- pp., Kagoshima Environmental Research and Service, ma major = Z. d. amami), Owston’s woodpecker Kagoshima. (in Japanese) Kagoshima Prefecture 2012. Nature of Kagoshima. 26 pp., (Dendrocopos leucotos owstoni), and Ryukyu Kagoshima Prefecture, Kagoshima. (in Japanese) Robin have been designated as Natural Monument. Kagoshima University 2012. “Consideration Report to Birdlife International selected the islands of the Establish a Management System based on the Scientific Knowledge for Registration of the Ryukyu Archipelago Ryukyu Archipelago including the Amami islands, as a World Natural Heritage Site 2011.” 80 pp., under the title “Nannsei Shoto,” as one of the Kagoshima University, Kagoshima. (in Japanese) “Endemic Areas of the World,” based on the Kimura, M. 1996. Quaternary Era Paleogeography of the inhabitation of endemic species such as the Lidth’s Ryukyu Archipelago. Journal of Geography 105: 259- 285. (in Japanese) jay and Amami woodcock. There are also many mi- Kizaki, K. and Ooshiro, I. 1980. Background of Ryukyu gratory birds, the Amami Islands is a mecca for bird Islands. In: Natural History of Ryukyu (Ed. Kizaki, K.), watchers. pp. 8-37, Tsukiji Shokan Publishing Co., Ltd., Tokyo. (in Japanese) The sweetfish, “Ryukyu-Ayu” (Plecoglossus Kizaki, K. 1997. The Way Plants and Animals Came, In: altivelis ryukyuensis) live mainly in Sumiyou Knowing Nature of Okinawa (Eds. Ikehara, S. and Bay and the rivers emptying into Yakiuchi Bay in Kato, Y.), pp. 14-32, Tsukiji Shokan Publishing Co., Amami-Oshima Is. Ryukyu-Ayu has been identified Ltd., Tokyo. (in Japanese) Miyamoto, J. 2010. Plants of Amami Islands. In: Kagoshima as a subspecies distinct from Ayu on mainland Japan Environmental Studies II (Ed. Kagoshima Environmental morphologically, ecologically, and genetically. This Studies Workshop, Kagoshima University), pp. 65-83, subspecies is thought to have an original history at Nanpoushinsha, Kagoshima. (in Japanese) Motomura, H. 2012. Diversity of Fish Species in Kagoshima the 1 million year level, with Tokara Strait as its Prefecture generated by the Kuroshio Current. In: Fishes boundary (Kagoshima Prefecture 2003). in Kuroshio Current (Ed. Matsuura, K.), pp. 19-43, Tokai University Press, Kanagawa. (in Japanese) 5. Conclusion Motomura, H. and Matsuura, K. (eds.) 2010. Fishes of Yaku-shima Island, Kagoshima, southern Japan. 264 pp., he tentative list of the “Amami-Ryukyu ” cov- National Museum of Nature and Science, Tokyo. Tering islands ranging from the Amami Islands Ministry of the Environment 2006. Red List of the Ministry of to the Sakishima Islands was submitted in January the Environment. Ministry of the Environment, Tokyo. Ministry of the Environment 2007. Ditto. 2013. Submission of this tentative list is part of the Ministry of the Environment and Japanese Coral Reef Society procedure to officially express the intention as a (eds.) 2004. Coral Reefs of Japan. 356 pp., Ministry of country to recommend the area as a world heritage the Environment, Tokyo, site. If this area is inscribed on the World Heritage Ministry of the Environment, Forest Agency, Agency for Cultural Affairs, Kagoshima Prefecture and List, Kagoshima Prefecture will be the only prefec- Yakushima Town 2012. Yakushima World Heritage Site ture in Japan which would have two World Heritage Management Plan. 24 pp., Ministry of the Environment; sites as a natural property, with Yakushima Is. al- Forest Agency; Agency for Cultural Affairs, Kagoshima Prefecture, Yakushima Town, Tokyo. (in Japanese) ready registered as one. Oota, Y. et al. 2001. Landform Development History of Kagoshima Prefecture has many islands, with Nansei Islands. In: Landform of Japan 7 Kyushu / various plants and animals living on them. Please Nansei Islands (Eds. Machida, H. et al.), pp. 301-314. come and meet the many plants and animals, and University of Tokyo Press, Tokyo. (in Japanese)

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