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Japanese Botanic Gardens and their Contribution to Plant Conservation

Volume 3 Number 8 - June 2002

Kanenori Miura

Due to the geographical location, topographical features and extensive range of climate from subtropical to subarctic and alpine zones, the Japanese archipelago (380,000 km²) is endowed with a rich flora with relatively high endemism. However, according to the Red Data Book on Vascular Plants published by the Japanese Environment Agency (EA) in 2000, 1665 species (about 24%) out of her 7,000 higher plant taxa are heavily threatened and 564 species are recognised as Critically Endangered.

Although botanic gardens, in general, are regarded as centres for plant conservation, to what extent have Japanese gardens adopted this role? What are the obstacles, if any to fulfilling this role and how can they be addressed?

This article attempts to illustrate ex situ plant conservation in Japanese botanic gardens and identify a strategy to improve their role. This is taken from a project by the author on the Plant Conservation Techniques Course held at RBG, Kew in 2001 entitled Strategy development of ex situ plant conservation in Japan

The Association of Japanese Botanic Gardens

The Association of Japanese Botanic Gardens (AJBG) was founded in 1966 as a corporate organization of the Ministry of Education. Currently there are 137 institutions and 119 individual members. Based on management status and functions, the 137 institution members are arranged into four subcommittees: School Gardens (6), National or Public Gardens (71), Private Gardens (21) and Medicinal Gardens (39). Some institutions have more than one site and in December 2001, 146 botanic gardens are listed by AJBG, with 79 Public Gardens and 22 Private Gardens.

In 1978, AJBG put forward guidelines for establishing and managing botanic gardens, which included definitions, criteria for area, number of living species for display, staff, guidelines for education activities and management. The definitions and some of other criteria are as follows:

  • Botanic Gardens defined here are botanical gardens or equivalent facilities established by national government, local public bodies, public corporate, or private sectors, and categorised into General Botanic Gardens and Special Botanic Gardens depending on their objectives.
  • General Botanic Gardens are botanical gardens which collect, cultivate and preserve many plants for increasing people’s knowledge about plants and cultivating people’s love for nature through displaying them and promoting scientific studies.
  • Special Botanic Gardens are botanic gardens or relevant facilities which collect, cultivate, preserve and display mainly specific plants for specific objectives.
  • The area of the garden should be more than 20 ha for General Botanic Gardens and more than 0.3 ha for Special Botanic Gardens.
  • The number of plant species for display should be more than 1500 for General Botanic Gardens and more than 500 for Special Botanic Gardens.

Some Features of Japanese Botanic Gardens

Although all botanic gardens belonging to AJBG meet the definitions and criteria, described in the box, there is significant variation in form, scale and objectives.

In Japan, the first recognized botanic garden appeared in the Edo period. In 1638, Miyakuen, which means the medicinal garden, was created by the Tokugawa feudal government. This garden was moved to its current location in Koishikawa Tokyo in 1684 and later became the Botanic Garden of the University of Tokyo in 1879. Apart from this exception, all other botanic gardens were founded after Meiji era (1868-1912), when Japan rushed to learn western culture and knowledge. Before World War II, 16 botanic gardens were founded, while most botanic gardens (89%) were created after the war, particularly after 1960 (76%).

More than half of the botanic gardens were created by local governments, such as prefectures, cities or municipals, mostly for public amenity, recreation and education. Subsidies from the Ministry of Construction or Ministry of Agriculture, Forestry and Fishery seem to be strong driving force to increase these public gardens particularly after 1960. Of the 28 gardens founded by the private sector, 7 were founded by pharmaceutical companies and many were founded as tourist attractions.

The majority of Japanese botanic gardens are relatively small. Gardens with more than 20 hectares represent less than a fifth (28 gardens - 19%), while there are 30 gardens (21%). with less than one hectare. Most of the smaller gardens are glass houses or medicinal school gardens. The largest garden is Kobe City Forest Plant Garden (142.6 ha).

There are 55 (38%) gardens with more than 1500 species on display, which meets the criteria for a General Botanic Garden and 21 (14%) gardens with less than 500 species on display, which is the basic criteria for a Special Botanic Garden. The largest collection of species is 12,000 in the Kyoto Prefecture Botanical Garden.
Figure 5 and 6 illustrate an important feature of Japanese botanic gardens; the majority of botanic gardens do not undertake scientific research (measured by the number of herbaria), but provide a public amenity, recreation, education or a tourist attraction. Of the 15 botanic gardens which undertake botanical research, four gardens are very active in conservation and two gardens also have active public education programmes.

A Case Study of Conservation Work by the Botanical Gardens of the University of Tokyo

Since the 1980s, an intensive species recovery project has been carried out in the Bonin Islands about 1000 km south of Tokyo.

The Bonin Islands, which belong to the Metropolis of Tokyo, consist of about 30 small islands; they have an extremely rich endemic flora and fauna as they are isolated from the continent and have been inhabited for the last 160 years. However, the agricultural development and deforestations started in the 19th century has heavily damaged the environment and grazing by escaped livestock, illegal collection of plants and natural catastrophes have made the situation worse. The emergency survey carried by the Environment Agency (now Ministry of Environment - MOE)) in 1985 showed that 80 species, about half the endemic species of Bonin Islands, were on the edge of extinction.

The first species recovery project was carried out by the University of Tokyo (UT) in cooperation with the Tokyo Metropolitan Government (TMG) from 1993. The project was taken over by MOE in 1994 and since them the Bonin Rare Plants Recovery Project, as it is called, has been carried on by the MOE in cooperation with the TMG and the UT targeting 11 species: Melastoma tetramerum, Rhododendron boninense, Calanthe hattorii, Calanthe hoshii, Pittosporum parvifolium,, Callicarpa nishimurae, Piper postelsianum, Asplenium cardiophyllum, Malaxsis boninennsis, Luisia boninensis, and Cirrhopetalum boninense. In addition to research and monitoring, reintroduction of plants cultivated at the Botanic Gardens of Tokyo University have been undertaken, since the remaining populations have seriously lost their viability.

The project has been very successful in species cultivation, but not as satisfactory in reintroduction. However, it has been reported recently that some individuals of Melastoma tetramerum, which were raised from the one remaining tree and reintroduced into its natural habitat, have become seedlings.

Survey on Endangered Species Conservation

A questionnaire was sent to Japanese botanic gardens in September 2001 by email to obtain information on current ex situ conservation efforts in botanic gardens and the managers’ opinion on ex situ measures which the government should undertake. A simple format of questionnaire was designed and sent to 60 botanic gardens where their email address could be obtained. 33 botanic gardens completed the form (55% garden surveyed and 24% AJBG institution members). The percentages of each category are 50% for School Gardens, 28% for National or Public Gardens, 24% for Private Gardens and 13% for Medicinal Gardens.

Five groups of questions were presented, 1) possession of EX (extinct) species, 2) possession of EW (extinct in the wild, but surviving in cultivation) species, 3) possession of CR (Critically Rare) and EN (endangered) species, with propagules in storage and involved in habitat restoration, 4) contribution to ex situ conservation and obstacles to promote it 5) necessary ex situ measures which should be undertaken by the government. The results of the survey are as follows:

  • No botanic garden has either living plants or seeds of EX species.
  • A few botanic gardens have two EW species. Out of 33 botanic gardens, 3 (9.1%) have living plants of Astragalus sikokianus, 5 (15.2%) have living plants of Viola stoloniflora; the latter was distributed to botanic gardens when the last population was lost by dam construction (Red Data Book of Vascular Plants Environment Agency, 2000). No botanic gardens posseses the other three EW species, such as Magnolia integra, Kalanchoe integra and Malus hupehensis.
  • Many botanic gardens have endangered species without conservation objectives. 21 botanic gardens (63.6%) possess CR and EN living plant species (the total number of them is 1044) from the range of 1~10 to 201~500; the majority is 1~10 (42.9%), 11~50 (33.3%). However, only three (9.1%) institutions include endangered species conservation as part of their management policy or objectives.
  • Seed and other propagule storage have been little practised by botanic gardens; 9 botanic gardens have the range of 1~10 species of seed and 1 has the range of 11~50 species of seeds.
  • Passport data, which records the status of collections, are generally insufficient. Out of the 21 botanic gardens which have endangered species, only two (9.5%) institutions say that there have passport data for the most endangered species, ten (47.6%) state the passport data is insufficient and four (19%) have no passport data.
  • One third of botanic gardens feel they contribute to ex situ conservation to some extent in terms of preservation of endangered species (10 gardens), education and information (7 gardens). Only 1 garden provides training of experts on plant conservation.
  • The main obstacles to promoting ex situ conservation in botanic gardens are lack of technical staff with knowledge of conservation and propagation of endangered species 16 (48.5%), lack of management policy 14 (42.4%), and lack of understanding among those concerned 10 (30.3%).
  • Many botanic gardens think that there is an urgent need for the government to understand the current status of endangered species precisely 23 (69.7%), to develop ex situ technical guidelines and to initiate a systematic collections of seeds or other propagules 16 (48.5%). The opinions are split whether to establish a large scale gene bank 12 (36.4%), or small scale field banks with seed bank functions 11 (33.3%).
  • 15 (45.5%) botanic gardens support the idea of commercialisation of endangered species to reduce the pressures on wild population, while eight (24.2%) gardens disagree. Apart from concerns that illegal collections from the wild may be sold as if they are from a cultivated source, there are concerns about encouraging the indiscriminate introduction of cultivated wild plants into natural habitats, which may affect the genetic integrity of the populations.
  • Majority 19 (57.6%) botanic gardens support involvement of amateur plant researchers and enthusiasts in ex situ conservation provided that appropriate education programmes are given, while four (12.1%) gardens disagreed with this idea.

Discussion and Recommendation on ex situ Conservation Strategies

Botanic gardens can play an important role in ex situ conservation. However, there are several issues which need to be addressed for them to be effective. In response to the questionnaire the three main obstacles to ex situ conservation in botanic gardens were lack of experts, lack of the objective in the management policy, and lack of understanding amongst the people concerned. How should these and other issues be sorted out?

First of all, the Ministry of Environment (MOE) needs to discuss the issue with Ministry of Land, Infrastructure and Transport, (MLIT), Ministry of Agriculture, Forestry and Fishery (MAFF) and Ministry of Education, Culture, Sports, Science and Technology (MECSST), since these ministries have strong links to botanic gardens through local governments or universities or scientific institutions. A common understanding should be established among the ministries concerned.

The Association of Japanese Botanic Gardens (AJBG) has one of the keys to this issue. AJBG, with 137 gardens members, holds a general assembly and four subcommittee meetings a year. Recently, every year it has held a botanic garden exhibition and overseas training. AJBG has guidelines for the establishment and management of botanic gardens. However, the guidelines do not include plant conservation, but reflect botanic garden objectives from tourism, public recreation, and education to research. Although they may not need to change the guidelines, it is strongly recommended that botanic garden roles on endangered species conservation be discussed at subcommittee meetings as well as at the general assembly. The MOE should work with MECSST and support these discussions. And also, it is strongly recommended that AJBG exchange information with Botanic Gardens Conservation International (BGCI), which is a global botanic gardens network mainly addressing plant conservation and education.

Endangered species in botanic gardens including foreign plants must be appropriately treated as soon as possible; since there is a risk of more genetic loss and contamination in the future. The results of the questionnaire show that passport data, which describe the status of collections, are insufficient in many botanic gardens and only a few gardens conserve seeds and other propagules. Although living collections, which generally have a narrow genetic representation of a species, are not considered good resources for gene bank projects, species which are extremely rare in the wild must be treated with care. Therefore, the MOE should conduct inventories on living collection of botanic gardens in cooperation with AJBG and provide technical advice to conserve genetic diversity.

Commercialisation of endangered species in botanic gardens may reduce the pressure on wild populations. In the questionnaire survey, 15 out of 33 botanic gardens agree with this idea, however 9 partially agree and 8 gardens disagree. One criticism is that its effectiveness is questionable because collectors tend to be interested in something rarer and more curious. Another opinion is that illegal collections might be sold as cultivated material in the market.

An interesting example which has been carried out in Aso, Kumamoto prefecture for Polemonium kiushianum, which became endangered mainly due to illegal collection and changes of grassland management. Cultivation of P. kiushianum was started in the 1980s by Aso Wild Plants Garden for its display. Since 1987, the garden has started to sell potted plants grown by local farmers for about 300 yen (approx £2 US$3), and sold 640 pots in 1990; it is locally observed that illegal collections have reduced since the plants became easily obtainable to public (Report on Polemonium Kiushianum Recovery Project Environment Agency, 1998.)

However, increasing concerns for diminishing plants in the Aso plateau raised another issue, which is that local plant enthusiasts have started to reintroduce cultivated plants into natural habitats without considering genetic disturbance. Similar cases are reported from other areas and in the worst cases people introduce species into natural habitats for aesthetic reasons. Although scientists are concerned about genetic contamination and the introduction of pests and diseases to natural habitats, local papers give favourable publicity to these misguided activities. These issues are little understood by media and the public, therefore commercialisation of endangered species should be fostered with very careful educational programmes. Guidelines of commercialisation and reintroduction of wild species should be developed by MOE through discussions with scientists and NGOs and other stakeholders.

Involvement of amateur plant enthusiasts in conservation is another important issue for ex situ conservation as in the past amateurs might have caused the problem by collecting from the wild. However, the amateur’s knowledge on plant distribution and cultivation are significant; and it is important to involve them in plant conservation.

In recent years, natural history has greatly depended on amateur efforts in Japan. In fact, of the 400 people who participated in the survey of Red List plants in 1994 and 1995, a considerable number were amateurs, although most were member of the Japan Plant Taxonomy Association. If we start a gene bank project, we will need more co-operators who search for target species and report the best collection time for seed or other propagules locally. Another expected role for amateurs is to support the cultivation of endangered species in botanic gardens. However, it is very important that amateurs understand the conservation objectives and their responsibility. Therefore, a pilot volunteer programme should be started based on careful guidelines.