Japan

Biodiversity
Flagship Species
Threats
Conservation

Japan includes more than 3 000 major and minor islands extending from about 22° to 46°N latitude, or from the humid subtropics in the south to a temperate zone (Hokkaido) in the north. It is located at the intersection of several of the Earth's crustal plates, three of which (the Pacific, North American, and Philippine plates) plunge into the depths below Japan where they generate forces that result in numerous volcanoes, hot springs, and mountains. These, in turn, have a strong influence on the climate and vegetation of the Japanese Archipelago.

In addition to the four main islands of Hokkaido (78 073 km²), Honshu (227 414 km²), Shikoku (18 256 km²), and Kyushu (36 554 km²), the Japanese Archipelago is composed of the Ogasawara-shoto (including the Ogasawara-gunto or Bonin Islands; and the Kazan-retto, also known as the Iwo or Volcano Islands), Daito-shoto, Nansei-shoto (including the Ryukyu Islands and Satsunan Islands), and Izushoto, all with distinctive vegetation that includes numerous endemic species and several endemic genera of plants and animals. The total land area of Japan is about 373 490 km². The country is mostly mountainous (about 73% of the land), and ranges in elevation from Hachiro-gata at 4 m below sea level in Akita Prefecture to the highest point, the summit of Mt. Fuji (Fujiyama or Fuji-san) at 3 776 m in Shizuoka Prefecture.

Japan was formed by the subduction of the Philippine and Pacific plates under the Eurasian Plate and by the opening of the Sea of Japan about 15 million years ago. Prior to those events, the islands that now make up Japan were part of the Asian Mainland, and the islands have been regularly connected by land bridges to the Asian Mainland. It is believed that Honshu is made up of at least two separate landmasses that drifted together. The slippage of these tectonic plates results in frequent and numerous earthquakes throughout the Japanese Archipelago. Some, such as the Kobe earthquake of 1995 and the Great Kanto or Tokyo earthquake of 1923, have resulted in the deaths of more than six thousand (Kobe) or tens of thousands (Tokyo) of people.

As a result of the wide latitudinal range of Japan, its position between the Pacific Ocean and the Sea of Japan, and its numerous high mountains, the climate varies considerably. During the winter, continental air masses from the high-pressure zone formed over eastern Russia generate winds that absorb large quantities of moisture as they move across the Sea of Japan. These moist air masses drop tremendous amounts of snow as they rise and cool when reaching the central mountains of Honshu, making it one of the snowiest regions on Earth. At the same time, the Pacific side of Japan is remarkably dry as the now moisture-depleted air masses cross the mountains (although at other times of the year, there is abundant rainfall in places). A rainy season (tsuyu) lasting about two months begins in early June and moves gradually from south to north, affecting both sides of Honshu, and eventually reaches Hokkaido, although that island is not as strongly influenced. In the winter, the Sea of Okhotsk is covered with drift ice to such an extent that fishing vessels operate from more southerly ports, although in recent years the amount of sea ice each winter has decreased.

The rainfall pattern reverses in early autumn, moving from north to south, but is not as severe. By late autumn most of Japan is generally clear. Annual precipitation in Tokyo (on the Pacific Ocean side) is 1 405 mm; at Owase, on the Kii Peninsula of southern Honshu, rainfall averages 4 000 mm per year; and at Takada, on the Sea of Japan side, it is 2 880 mm per year, about half of which is snow. Yaku-shima, just south of the southern tip of Kyushu, is among the wettest places in the world, receiving well over 5 000 mm of rain per year in places. Japan rarely suffers from a lack of rain, as can be seen in the lush cover of vegetation throughout the archipelago. Overall, the climate is generally mild, being strongly influenced by the warm Kuro (Kuro-shio) and Tsushima currents from the south. The cold Chishima (Oya-shio) Current that moves southward from the Kuril Islands sometimes brings heavy fog to the east coasts of Hokkaido and northern Tohoku District. Such fog can damage the rice crop, which requires sunny days for successful growth.

Vegetation in Japan ranges from boreal mixed forests (often called subalpine or subarctic in the Japanese literature) of Abies (fir), Picea (spruce), and Pinus (pines) on Hokkaido and at high elevations southward through Honshu and Shikoku, to subtropical broadleaf evergreen forests and mangrove swamps in the south. Indeed, Japan marks the world's northern limit of mangroves on the island of Yaku-shima. High elevations on Honshu and Shikoku support alpine vegetation near the summits of many mountains. Subalpine vegetation and natural beech forests, although small in scale, are distributed throughout the region and are near the southern end of their range. Alpine vegetation occurs near sea level in several places on Hokkaido and also near and on the tops of the many mountains and even at lower elevations in areas with active fumaroles. The soils around the fumaroles support vegetation that is peculiar to the vicinity where it occurs. The plants in these areas usually prefer soils of low acidity.

The main species of trees on Hokkaido north of the Oshima Peninsula (south of Sapporo) are Abies sachalinensis, Picea jezoensis, and P. glehnii, which frequently grow intermixed and in association with birches (Betula ermanii and B. maximowiczii). On the Oshima Peninsula, Fagus crenata (Japanese beech) appears and marks the boundary between the boreal and cool temperate zones. The conifer forests on Honshu are only on the highest mountains (generally between 1 600 and 2 500 m elevation), such as the Japan Alps, but the diversity of conifers is higher than on Hokkaido and includes Tsuga diversifolia, Abies veitchii, A. mariesii, Picea koyamai, and P. maximowiczii. Within the conifer forest zone on Honshu are often pure, conspicuous stands of Betula ermanii. Honshu is divided throughout its length by high mountains and, at all elevations, there is a clear difference in vegetation between the Pacific side and Japan Sea side of the island. The western side of the mountains, facing the Japan Sea, receives abundant moisture in the form of snow in the winter. Plants on the Japan Sea side have adapted to the heavy snow cover, as much as 10 m deep in some places, and are often distinct at the specific or infraspecific level from their Pacific side counterparts. The Pacific side of Honshu, in contrast, is dry and sunny in the winter and receives very little snow.

There are also a few pure and old-growth conifer forests on Honshu: Thujopsis dolabrata in northern Aomori Prefecture;Cryptomeria japonica forests in Akita Prefecture;Chamaecyparis obtusa forests in southwestern Nagano Prefecture; and a Sciadopitys verticillata forest on Mt. Koya in Wakayama Prefecture. These forests were preserved because they were the property of family clans, Shinto shrines, or Buddhist temples that protected them from cutting. Often the deciduous trees were cut, but the conifers were protected so that over time the composition of these forests became more homogeneous.

Below the conifer forests are cool temperate broadleaf deciduous forests, primarily of Fagus crenata intermixed with Quercus crispula (oak), with a dense undergrowth of Sasa. On the Pacific side of Honshu, Abies homolepis, often intermixed with Fagus and A. firma, sometimes forms pure stands adjacent to the Fagus forests. On the Sea of Japan side, broadleaf evergreen forests are adjacent to the Fagus forests. Sasa is also an undergrowth plant in the Fagus forests on the Japan Sea side of Honshu, but the species are different from those on the Pacific side. Other trees in the Fagus forests are numerous, and include several species of Acer (maples), Tilia (linden), Fraxinus (ash), Prunus (cherries), Magnolia, Kalopanax, Sorbus (mountain ash), with Aesculus (chestnut), Cercidiphyllum (Katsura), Euptelea, and Alnus maximowiczii in more moist places.

Below the Fagus forests are warm temperate broadleaf forests primarily made up of various members of the Fagaceae (beech and oak family), including several species of Quercus, Castanopsis, and Lithocarpus, Lauraceae and Theaceae, with an admixture of numerous other trees species, both evergreen and deciduous.

Warm temperate vegetation, characterized by broadleaf evergreen trees and also trees and plants of more southern affinities, extends from central Honshu to Shikoku, Kyushu, and southward. In the northern portion of its range, this vegetation type is restricted mostly to the immediate coastal areas, but extends farther inland towards the south. Characteristic warm temperate broadleaf evergreen trees are various species of oak (Quercus subgenus Cyclobalanopsis), Lithocarpus, Castanopsis, Cinnamomum, Machilus, Camellia, and Cleyera. This association marks the northernmost extent of the Fagaceae-Lauraceae-Theaceae forests that dominate in Southeast Asia. These forests reach 38°N latitude on both the Japan Sea and Pacific coasts of Honshu, where they give way to temperate broadleaf deciduous forests.

The subtropical island chains lying to the south of Japan support a flora and fauna different from the main Japanese Islands, including a large number of endemic plants and animals. The Izu-shoto, Ogasawara-gunto (or Bonin) and Kazan-retto (Iwo or Volcano) islands comprise 30 or more volcanic islands that extend southward from Tokyo in the Pacific Ocean. The Izu-shoto stretches from Oshima in the north, where the high point is 854 m, to Torishima in the south. The Ogasawara-gunto can be divided into three groups: Muko-jima, Chichijima-retto, and Hahajima-retto. The largest island, Chichi-jima, has an area of 24 km². The Ogasawara-gunto have a diverse topography and, although much of the land has been cleared on the northernmost islands, some primary forest still remains in the more inaccessible areas to the south. Broadleaf evergreen forests cover extensive areas on Haha-jima, parts of Chichi-jima, and some of the smaller islands, but most are secondary. Primary native forests are in the more remote and inaccessible parts. Kazan-retto comprises three islands, one of which, Iwo-jima (which means Sulfur Island), is a submerged caldera better known as a battleground during World War II.

The Nansei-shoto Islands consist of more than 100 islands, from Yaku-shima, south of Kyushu, to Iriomotejima, located about 200 km east of Taiwan. The island chain comprises two main groups: the Satsunan Islands, including the Oosumi Islands, Tokara-retto, and Amami-shoto, and the Ryukyu Islands, including Okinawa-shoto and Sakishima-shoto. The northern islands are more temperate in terms of vegetation cover, while south of Amami the flora is more subtropical. Okinawahonto, an island in the Okinawa-shoto and the largest island in the Nansei-shoto at 1 200 km², contains the highest percentage of natural forest in Japan outside of Hokkaido. Iriomote-jima (293 km²) and northern Okinawa also support especially extensive areas of broadleaf evergreen forests. The ecosystems of the Ryukyus, such as mangroves and coral reefs, are rarely found in other areas of Japan. The Oriental faunal region, and the southern limit of the Palaearctic, integrade in the Nansei-shoto such that these islands harbor fauna from both regions, as well as their own unique species (Stattersfield et al. 1998).

Despite the relatively small land area and the general perception of a homogeneous society, Japan is as diverse culturally as it is biologically, mainly due to the same reasons: its geological and geographical complexity. High mountains and ocean, as well as domestic travel restrictions that were in place until the late 1800s, virtually divided the country into numerous cultural, if not ethnic, groups. The Japanese language is a distinct language with no linguistic affiliation with other languages, but has a variety of dialects. There is also a completely different language, Ainu, which is spoken by the Ainu people in Hokkaido and the northern parts of Honshu. However, the Ainu language is said to be at the verge of extinction, since few people can speak it, and the Ainu culture was nearly lost until recent interest in it by the remaining Ainu has given it new life (Fitzhugh and Dubreil 2000). Despite the diversity within the Japanese language and culture, Japanese people's love of nature is uniform and strong, and has a long history. This may be due to the fact that Japan is such a small country with a mostly mountainous topology and very little arable land. This has forced the Japanese people to use natural resources in a sustainable manner and to live harmoniously with nature. This spirit is also based on the religious beliefs of Buddhism and the indigenous Shintoism. The word “nature” or shizen in Japanese literally means “being within” or “being part of.” Evidence of such a spirit can be found in Man'yoshu, an early anthology of poetry and one of Japan's earliest recorded documents remaining, where more than 150 species of plants and over 70 animal species are expressed in the most popular poems of Japan written before the eighth century. Another distinct connection between the Japanese people and nature can be seen in Haiku, the very short 17-syllable poems, which require as a rule that nature be expressed.

There are approximately 5 600 species of vascular plants in Japan (ferns and fern allies, conifers, and flowering plants). About 35% of the plants, or some 1 950 species are believed to be endemic (Iwatsuki et al. 1993; 1995a, b; 2001). There are three endemic plant families, Sciadopityaceae, Glaucidiaceae, and Pteridophyllaceae, and around 20 endemic genera, seven of which are monotypic. The endemic genera include Sciadopitys (one species, S. verticillata), Anemopsis, Ranzania (one species, R. japonica), Glaucidium (one species, G. palmatum), Pteridophyllum (one species, P. racemosum), Dendrocacalia (one species, D. crepidifolia), Mallotopus, Kinugasa, Macropodium, Japanolirion (one species, J. osense), Tsusiophyllum (one species, T. tanakae), Boninia (two species, B. grisea and B. glabra), Boninofatsia (two species, B. oligocarpella and B. wilsonii), Platycrater, Ancistrocarya, Perillula, Alectorurus, and Diaspanthus. There are also a number of interesting near endemics, such as Trochodendron aralioides, an unusual and primitive vessel-less angiosperm that occurs sporadically from central Honshu southwards, but otherwise occurs elsewhere only on Taiwan. Interestingly, though, the genera that are considered characteristic of the Japanese flora are rather poorly represented on Taiwan, with Japan's flora having come mostly from east-central China, Korea, and the islands and mainland to the north, whereas Taiwan's came from the Philippines (southern tip) and southeastern China.

On Ogasawara-shoto, there are about 500 native plant species, of which about 43% are endemic; of the native tree species, endemism is around 75% (73 of 97 species) (Kitayama 1991). Two genera, Dendrocacalia and Boninia, are endemic to these islands, and a third, Dendrocacalia crepidifolia, is endemic to, but widespread on, Haha-jima.

About 90 genera of the plants in Japan are members of what has been referred to as the Arcto-Tertiary Geoflora (Boufford and Spongberg 1983; Wen 1999). Genera in this group usually represent ancient lineages that were once distributed around the world in the Tertiary Period. Distinctive genera include: Buckleya, Caulophyllum, Diphylleia, Stewartia, Schisandra, Illicium, Wisteria, Lespedeza, Penthorum, Itea, Astilbe, Mitella, Menispermum, and Shortia. Many of them are well known as fossils at high latitudes worldwide, hence their designation as “Arcto-Tertiary.” Although the forests in which the genera occurred were once widespread and continuous, they now have a very fragmented distribution. Members of this group have one or more species in two or three widely separated parts of the world: southeastern North America, Japan, and China. Although the species in each region are distinct from those in the other regions, they are similar to each other in that their generic placement has never been questioned. The origins of this biogeographic pattern have been a source of speculation since it was discovered nearly 200 years ago, and even attracted the attention of Charles Darwin as he was preparing his book The Origin of Species.

Although vertebrate diversity is not especially high in Japan, levels of endemism are marked. Among mammals, for instance, only 91 species are recorded, but half (46) are endemic. Moreover, there are six endemic genera, three of which are monotypic: the Amami rabbit (Pentalagus furnessi, EN), found on Amamioshima and Tokuno-shima in the Amami-shoto in the Nansei-shoto; the Japanese dormouse (Glirulus japonicus, EN), found on Honshu and Shikoku; and the Ryukyu long-tailed giant rat (Diplothrix legatus, EN), restricted to the Ryukyu Islands of Amami-oshima and Tokuno-shima, and Yanbaru Forest on northern Okinawa. The other three endemic genera (Phaulomys, Tokudaia, and Urotrichus) are represented by two species each. The spiny rats of the genus Tokudaia have severely restricted ranges, with the Ryukyu spiny rat (T. osimensis, EN) found only on Amami-oshima, and Muennink's spiny rat (T. muenninki, CR) known only from Yanbaru Forest. Sado Island (857 km²) off western Honshu has two endemic mammals, the Sado shrew (Sorex sadonis, CR) and the Sado mole (Mogera tokudae, EN).

Japan's reptile fauna includes 64 species, 28 of which are endemic, and four are considered threatened: the Okinawa black-breasted leaf-turtle (Geoemyda japonica, EN); Kikuzato's brook snake (Opisthotropis kikuzatoi, CR), found only on the Kume-jima in the Okinawashoto in the Ryukyus; the Amami takachiho snake (Achalinus werneri, VU), confined to Amami; and the Tokashiki ground gecko (Goniurosaurus kuroiwae, VU), from the Ryukyus. Amphibians include 58 species, of which 44 are endemic. The amphibian genus Hynobius is also particularly well represented, with 15 of the 23 known species endemic, one of which, the Oki salamander (H. okiensis, EN), is confined entirely to Dogo, of the Okino-shima in Shimane Prefecture.

There are 368 bird species known to occur regularly in the hotspot, although only 15 are endemic. One of these, the Okinawa woodpecker (Sapheopipo noguchii, CR), is the only representative of an endemic genus, and is found in Yanbaru Forest. Three Endemic Bird Areas (EBAs), as identified by BirdLife International (Stattersfield et al. 1998) are found within Japan: the Izu Islands, with two species confined entirely to this EBA; the Ogasawara Islands, with a single restricted-range species confined to it, the Bonin honeyeater (Apalopteron familiare, VU); and Nansei-shoto, with seven species confined to this EBA, five of which occur only on Amami and Okinawa.

The freshwater fish fauna is relatively small, with 214 native species of which 52 are endemic. Inland waters are dominated by fishes entering from the sea, but they also include a significant representation of strictly freshwater groups such as minnows (Cyprinidae) and loaches (Cobitidae and Balitoridae) that have undergone diversification within the hotspot. These radiations account for nearly half of the endemic species and three of its four endemic genera. Species in ancient lineages (five lampreys and four sturgeons) are an important component of the fauna, placing it among the highest-ranking hotspots in terms of phyletic rarity of fishes.

Some invertebrate groups are fairly well documented in Japan. For example, around 237 butterfly species are thought to be native to the country, although this figure includes naturalized species (Matsuka 2003), while of 24 species of tiger beetles recorded, six are endemic (D. Pearson, pers. comm.).

Japan's flora includes a number of rare, endemic plants that are well-known favorites in gardens both in Japan and in temperate areas worldwide. Shirane-aoi (Glaucidium palmatum) has perhaps the most extensive range, occurring from central Honshu to southern Hokkaido, and is more common on the Sea of Japan side of Honshu. The large, blue-purple, or rarely white, flowers make it a favorite horticultural subject, and are especially noticeable when in bloom in patches of open ground surrounded by deep snow. Togakushisgouma (Ranzania japonica) is rarer still, and is found only in the high mountains from central to northern Honshu. The pale purple flowers of this species are particularly striking.

Kouya-maki (Sciadopitys verticillata), a conifer tree, occurs from central Honshu to Shikoku and Kyushu. It is unusual in having pairs of needle-like leaves completely fused and then borne in whorls near the apex of the branches. An excellent Sciadopitys forest, formerly belonging to a Buddhist temple, occurs on Mt. Koya in Wakayama Prefecture. Sciadopitys also occurs in the Sohayaki region of Kyushu, Shikoku, and the Kii Peninsula of Honshu. Although Sciadopitys is endemic to Japan, other plants in the Sohayaki floristic region often have relatives in western China.

Urahagusa (Hakonechloa macra) is a rather rare and local grass that grows on wet, rocky cliffs in the Tokai region of Japan. Because of some forms with variegated leaves and its graceful arching habit and tendency to form dense mounds, it is a favorite pot and garden plant.

Perhaps the best-known flagship in this hotspot is the Japanese macaque (Macaca fuscata), the most northerly-living non-human primate, found on Honshu, Shikoku, and Kyushu (and a few other islands). These animals play a prominent role in Japanese culture, and are famous around the world as the “snow monkeys,” which regularly romp in the snow in winter and also make use of Japan's abundant volcanic springs. Japanese macaques were also very important in the evolution of the science of primatology, with some of the very first field studies of wild primates having been conducted by pioneering Japanese researchers back in the 1950s. There is also a second macaque endemic to Japan, the Yaku-shima macaque (M. yakui), found only on the island of Yaku-shima. It used to be considered a subspecies, but is now considered by many experts to warrant full species status.

The Iriomote cat (Prionailurus iriomotensis) is unique to Iriomote-jima. The species was described in 1967, when it was noted as being one of the most primitive of Asian felids. Since then, studies have suggested it may be a subspecies of the leopard cat (P. bengalensis). The species is thought to number no more than 100 individuals. Another Ryukyu endemic is the Amami rabbit. Following a dramatic decline in numbers in the early twentieth century, the species was declared a national monument and given complete legal protection, although this status confers no protection on the species' habitat. The Amami rabbit habitat is subject to extensive fragmentation, particularly of mature forests (which make up 10% of Amami and 30% of Tokunoshima), and introduced mongooses are also a significant threat; it is estimated that perhaps only 2 500 individuals survive.

The Japanese giant salamander or Osanshouo in Japanese (Andrias japonicus) is distributed in western Honshu, Shikoku, and Kyushu, and is one of the world's largest amphibians. This extraordinary species can grow to more than one meter in length (the young taking five years to reach maturity), and feeds on fish and crustaceans. The species was put under protection in 1951, after its population was threatened by human consumption. No longer part of the Japanese diet, its population has grown and the species is designated as a special natural monument in Japan. Another flagship amphibian is Ryukyu spiny newt or Iboimori (Echinotriton andersoni, EN), which suggests crocodilian features. This species is distributed on six islands: Amami-oshima, Tokuno-shima, Yoro-shima, Okinawa-honto, Sesokojima, and Tokashiki-jima. Like its larger relative, it has been designated as a national monument in Okinawa and Kagoshima prefectures.

One of the best avian flagships is the Okinawa rail (Gallirallus okinawae, EN), endemic to Okinawa Island, where it is confined to Yanbaru in the northern quarter of the island. The population of this species is estimated to be around 900 pairs or 1 5002 100 birds. Yanbaru is also home to the Okinawa woodpecker, with the main breeding areas along the mountain ridges between Mt. Nishime-take and Mt. Iyu-take. This species was considered close to extinction in the 1930s. In the early 1990s, the breeding population was estimated to be only 75 birds, and it now stands at between 146 and 584 birds.

Finally, Japan supports some very important waterbird populations, notably those of the resident redcrowned cranes (Grus japonensis, EN) on Hokkaido, and the wintering hooded cranes (G. monacha, VU) and white-naped cranes (G. vipio, VU) at Izumi on Kyushu, where around 85% and 40% of the global populations of these species, respectively, overwinter. In large part, these unnaturally large concentrations are due to food provision, as natural habitats and sufficient food sources no longer exist there, such that the cranes exist largely on intensive management, which is supported by the Japanese government. Such unnatural concentrations put the populations at an elevated risk of disease or some other such catastrophe (BirdLife International 2003).

Fortunately, in some ways, approximately 70% of Japan's 127.5 million people (Population Reference Bureau 2003) are concentrated on 3% of the land area, resulting in a high population density in those areas, but leaving other areas relatively sparsely populated. That said, human settlement in the vicinity of protected areas is considerable, with an estimated 33 million people living within 10 km of protected areas in 2002 (L. Gorenflo, pers. comm.). Although threats to Japan's environment from logging interests are not high because of the high cost of Japanese timber compared to cheap imported timber from other parts of the world, the affluence of Japanese society in general, the high GDP per capita achieved within a few decades following World War II, the reduced work week in recent years, and the resultant increase in leisure time have placed a different type of strain on the environment. Forests are being cleared for ski resorts and golf courses, which were promoted in the 1980s by government policy, and more roads have been built to accommodate the steady increase in automobiles and the desire by many people to use private rather than public transportation. In recent years, too, fast public transportation has been expanded. It is now possible to travel to such remote parts of Japan as Yamagata and Akita in the north by bullet train, the Shinkansen, in less than three hours from Tokyo. Many more vacationers travel to those once remote and sparsely populated areas. With the increase in tourists has come a greater demand for services and recreational facilities, which in turn has put more pressure on undeveloped areas.

Since World War II, the country's high-elevation conifer forests have been under the administration of the Forestry Agency of Japan. In response to demands for timber and pulp following World War II, the agency promoted clear-cutting of these forests and the replanting of deforested areas with Larix leptolepis. Today, plantations are widespread throughout Japan, with about 90% of them made up of Cryptomeria japonica (Sugi), Chamaecyparis obtusa (Hinoki), and Larix leptolepis (Kara-matsu), all native Japanese species. Fagus was traditionally not used for construction until after about 1900. From then on, Fagus was used in increasing amounts for furniture, pulp, and construction, and during World War II for building light aircraft. Clear-cut areas that supported Fagus have been replaced with Cryptomeria or Larix plantations, or by pure stands of Sasa where it has been impossible to establish Cryptomeria or Larix. Natural Fagus crenata vegetation still occurs in the central mountainous areas of Honshu, but is replaced by evergreen broadleaf forests in the southern parts of the island.

As a result of the National Survey on the Natural Environment, Japan maintains vegetation maps (scale 1:50 000) covering the entire national landmass, with 766 plant-community categories. The plant communities are classified into ten types: natural vegetation of grasslands; natural vegetation of moorlands; natural vegetation of forests; secondary forests approximating the natural vegetation; substitute vegetation of secondary forests; planted forests; substitute vegetation of high-profile grasslands; substitute vegetation of lowprofile orchards; substitute vegetation of low-profile paddies and fields; and urban land. When considering the percentage of each vegetation type occupying the overall national land area, forests (natural forests, secondary forests approximating natural forest, secondary forests, and planted forests) comprise 67.5% of the national land. Natural forest vegetation constitutes 18.2%. Adding the natural vegetation of grasslands and moorlands provides a total natural vegetation of 19.3%. Secondary forests (including secondary forests approximating natural forest) comprise 24.6% of the national land, while planted forests occupy 24.7%, secondary grassland 3.2%, paddies and fields 22.7%, and urban land 4.0%. The natural forests and natural grasslands referred to here indicate forests or grasslands that are climax or are regarded as climax. The most heavily forested region is the island of Hokkaido, of which 50% is covered with natural vegetation. Shikoku, however, has the highest percentage of forest cover in Japan, while Kyushu has the highest percentage of land in cultivated forests, paddy fields, and croplands in the country. Overall, deforestation has now ceased to a large degree in the lowlands, and there are still extensive tracts of forest cover in the higher-lying regions.

Besides forested areas, coastal regions and wetlands have also been subject to disturbance. On Hokkaido, the wetlands favored by nesting red-crowned cranes continue to be lost to development, mainly agricultural expansion, river channelization, and road building. For instance, one-third of almost 300 km² of marshland in Kushiro has been converted to agricultural, industrial or residential use since the 1970s (BirdLife International 2003).

Unfortunately, as a result of past habitat loss and also the effects of hunting and pesticide use, several species have undergone precipitous declines in their populations, including the oriental stork (Ciconia boyciana, VU), which no longer breeds in Japan, and the crested ibis (Nipponia nippon, EN), which is now known to survive only in the You Prefecture in Shaanxi Province in central China, where it is a localized breeder. In both cases, efforts are under way to reintroduce these species to Japan, with several captive-bred crested ibises from China having been sent to Japan, and similar plans to reintroduce captive-bred oriental storks. The population of short-tailed albatross (Phoebastria albatrus, VU) crashed to near extinction during the twentieth century following massive exploitation for its feathers, although protection since the 1960s has helped the population to recover; today, it breeds only on Torishima and the Senkaku Islands (BirdLife International 2003).

Like much of the rest of Japan, the Ryukyus and Ogasawaras have suffered from habitat loss due to the planting of timber plantations and urban development (and volcanic eruptions in 2000 resulted in serious damage to forests on Miyake-jima in the Izu Islands). Almost all the original subtropical forest on the Ogasawaras has been cleared, likely one of the factors that led to the extinction of three avian endemics during the nineteenth century (Bonin wood-pigeon, Columba versicolor; Bonin thrush, Zoothera terrestris; and Bonin grosbeak, Chaunoproctus ferreorostris). In the Ryukyus, only small areas of forest remain on Amami and Okinawa, mainly in protected areas, and mature forest now only covers less than 5% of Amami (BirdLife International 2003).

As with other subtropical parts of the world, one of the greatest threats to the native fauna and flora of Japan is from alien plants and animals, some of which were introduced for the purposes of snake control, including the Indian grey mongoose (Herpestes edwardsi), Javan mongoose (H. javanicus), and Siberian weasel (Mustela sibirica). For example, the introduction of the Siberian weasel to Miyake-jima in the 1970s and 1980s caused significant declines of Japanese night-herons (Gorsachius goisagi, EN) and Izu thrushes (Turdus celaenops, VU). On Amami, the Javan mongoose is thought to be responsible for declines in the Amami woodcock (Scolopax mira, VU) and Amami rabbit. Other introduced species in Japan include the fish Tilapia zillii and the toad Bufo gargarizans miyakonis, while introduced goats are a problem on some islands. Largemouth bass (Micropterus salmoides), too, pose a serious threat to native fishes throughout Japan.

Although Japan's 28 national parks have been designated to preserve “areas of the greatest natural scenic beauty,” they also protect some of the richest areas of biodiversity. Together, they cover about 5.5% of Japan's land area. In addition to the national parks, there are numerous quasi-national parks, prefectural natural parks, and prefectural wildlife protection areas. Taking into account all protected areas in IUCN categories I to IV, just under 6% of this hotspot can be considered to have a high level of protection, although as much as 16% of the hotspot has at least some form of legal protection when one also includes those protected areas not classified in these categories. There are also two Natural World Heritage Sites in Japan, both established in 1993, namely Shirakami-sanchi, in northern Honshu, and Yaku-shima in the Satsunan-shoto, which contains ancient trees of sugi or Japanese cedar. Many of the parks, or parts of the parks, may not be completely preserved areas, and often there are private agricultural lands or other commercial development activities within the park. Furthermore, there are weaknesses in reserve management in some areas, such as in the Izushoto, which although declared a national park, continues to suffer habitat loss.

The main obvious gaps in the protected area system are in the Ryukyus; small, protected areas exist in northern Okinawa and on Amami, but most forested areas are not properly protected. One example is Yanbaru, which supports important populations of six of the 32 Critically Endangered and Endangered species in Japan, including the entire global populations of Okinawa rail and Okinawa woodpecker. Around 25% of Yanbaru on the eastern slope of the central montane area is located in the U.S. Marine Corps Training Area, while the rest of the forest is threatened by clear-cutting and removal of forest undergrowth: during a 13-year period, from 1979 to 1991, some 24 km² of forests were cut down, more than 60% of which was in the central part of the forests, while it has been estimated that the undergrowth has been removed from half of the natural forests (Ito et al. 2000). It is also worth noting that 19% of Okinawa-honto's land area is under exclusive use by U.S. military bases.

The policy until now regarding protected areas has been to try to establish the parks with the least negative impact on the local economy, while at the same time preserving landscape areas of great national importance. Wildlife within the parks is strictly protected, and the destruction and collecting of plants and animals is prohibited. The parks, however, are used for such activities as hiking, skiing, mountain climbing, camping, boating, swimming, bird watching and general sightseeing. On the Ogasawaras, more preserves have been established and tourism has become regulated.

Although pressures on once-remote parts of the country have increased, in recent years the people of Japan have returned to embracing the concept of a green, sustainable world where humans value and care for their natural resources, and again recognize themselves as one part of the environment, just as their ancestors did. A significant indication of the value being placed on renewable resources and green technology is the Cosmos Prize, one of the world's top environmental awards, established by the Expo'90 Committee and presented annually by the Expo'90 Foundation of Japan. Expo'90 was an event dedicated to the theme “The Harmonious Coexistence of Nature and Mankind: How we as human beings can truly respect and live in harmony with nature.” The purpose of the prize is to honor those who have, through their work, applied and realized the ideals promoted at the Expo, but it has also focused the attention of the public on the need for conservation and the preservation of nature. Nature and greenery are now constantly being mentioned in advertising, by the news media, and in government policy announcements.

Finally, it is worth mentioning that Japan in recent years has become an important player in international biodiversity conservation and an advocate for the hotspots. Indeed, the Japanese Government is one of five partners (along with the World Bank, the Global Environment Facility, the MacArthur Foundation, and Conservation International) in the Critical Ecosystem Partnership Fund (CEPF), which is providing $125 million over five years to hotspot conservation. Now that Japan itself has entered the hotspot list, we hope that the country's commitment to these critically important regions of our planet will increase even more.

< previous section  < index >  next section >