Ex situ plant conservation: A key role of Chinese botanic gardens in implementing China's Strategy for Plant Conservation
Volume 7 Number 2 - July 2010
China is home to approximately 10% of the world’s plant diversity and more than half of its 33,000 species are endemic (MEP, 1998; MEP, 2007). This tremendous plant diversity encompasses a huge number of species of bryophytes (c. 2,200 species), pteridophytes (c. 2,600 species), gymnosperms (c. 250 species), and angiosperms (>30,000 species). Furthermore, a long history of agricultural civilization and crop plant domestication in China has generated an enormous number of cultivars of important crops, vegetables, fruits and ornamentals (CSPCEC, 2008).
However, plant diversity in China is increasingly threatened, with some 4,000-5,000 plant species thought to be at risk of extinction. The timely launch of China’s Strategy for Plant Conservation (CSPC) in 2008 aims to tackle the urgent issues of plant conservation and demonstrates China’s firm commitment to the environment, aligned with the Global Strategy for Plant Conservation (GSPC), as well as China’s international obligations as a signatory to the Convention on Biological Diversity (CBD). Chinese botanic gardens have made great progresses in the implementation of China’s Strategy for Plant Conservation.
“China’s Strategy for Plant Conservation is an action plan to provide overall guidance for Chinese plant diversity conservation.”
Status of Chinese botanical gardens
Ancient Chinese gardens can be dated back probably to the Xia dynasty (2100-1600 BC) when unimproved wild species were used as ornamentals. Even before then, c. 2800 BC, the legendary Shennong established a medicinal garden, currently regarded as the earliest botanic garden in the world (Xu, 1997; Lopez-Pujol et al., 2006). The first western concept botanic gardens, designated for plant introduction and botanical research, were established during 1920’s -1930’s but development was slow until the mid-1970s. Since then there has been rapid growth, up to a total of 160 botanic gardens in existence today (He, 2002).
145 of the 160 botanic gardens in China are located in temperate and subtropical regions, with the majority being located in eastern and south-central China. Only 10% of the gardens can be found in western China. In the past 10 years, more efforts have been put towards to the establishment of botanic gardens in southern and southwestern China where centers of plant diversity and high plant endemism occurs.
Management of Chinese botanic gardens differs considerably with the different government agencies they are administered by. Most ex situ conservation programs are conducted by the botanic gardens that fall under the administration of the Chinese Academy of Sciences (CAS). Gardens under the Ministry of Housing and Urban-Rural Development (MHURD), State Forest Administration (SFA), Ministry of Health (MOH) and state universities, etc. do conduct some ex situ conservation activities, but their priorities are more focused on landscaping, tourist attraction, and public education. The overall coordination of the national plant conservation strategy and its implementation is provided by the CAS Botanical Garden Working Committee and the Chinese Botanical Garden Society.
The botanic gardens of the Chinese Academy of Science
The Chinese Academy of Sciences (CAS) is the principal national academic organization in natural science and its affiliated botanic gardens are designated as essential organizations dedicated to the exploration, utilization and conservation of strategic plant resources. There are a total of 16 botanic gardens (arboreta) under the management of CAS or jointly managed by CAS and local government:
• South China Botanical Garden (SCBG),
• Xishuangbanna Tropical Botanical Garden (XTBG),
• Wuhan Botanical Garden (WBG),
• Beijing Botanical Garden (BBG),
• Nanjing Botanical Garden (NBG),
• Lushan Botanical Garden (LBG),
• Guilin Botanical Garden (GBG),
• Kunming Botanical Garden (KBG),
• Turpan Botanical Garden (TBG),
• Qinling Botanical Garden (QBG),
• West China Subalpine Botanical Garden (WCSBG),
• Fairy Lake Botanical Garden (FLBG),
• Chenshan Botanical Garden (CBG),
• Three Gorges Botanical Garden (TGBG),
• Shenyang Arboretum
• Dinghushan Arboretum
These 16 botanic gardens are distributed over 10 provinces (or autonomous regions) in China, occupying a total area of 14,000 hectares.
Ex situ conservation in Chinese botanical gardens
The combined living collections of the 10 main CAS botanic gardens consist of some 24,667 plant species. These cover approximately 95% of the ex situ collections of all Chinese botanic gardens. It is estimated that approximately 80% of the species in these collections are native Chinese plants and 20% are introduced species. These collections provide an important reserve of plant resources for sustainable economic and social development in China.
Ex situ conservation is very important in Chinese botanic gardens. In 1998, China re-evaluated its global role in plant conservation and the sustainable use of plant diversity and CAS developed a new strategy for botanic garden research. As a result a 5-year master plan was formulated, taking CAS botanic garden development into the 21st century. Subsequently, CAS re-organized its botanic gardens and designated three National Core Botanic Gardens and also promoted the concept of Scientific Botanic Gardens. Botanic gardens were viewed as supporting platforms for innovation research in life science, and were developed in line with the leading international botanic gardens. CAS initiated a “Knowledge Innovation Program” at the three core gardens, XTBG, WBG and SCBG and this prompted the idea of establishing a National Scientific Botanic Garden in China.
The National Core Botanic Gardens
As the projects continue successfully, the capacity in science and technology innovation have shown great improvement in the three core botanic gardens. These gardens have reinforced their efforts in ex situ conservation and the collection and conservation of resource-plant species has been extensively enhanced. For example, XTBG increased the number of taxa under ex situ conservation from about 4,000 in 2002 to about 10,000 in 2005, of which 7,420 have been identified correctly. Thus XTBG became the first garden in China to conserve 10,000 plant taxa and one of the few botanic gardens in the world with such a large number of species in its living collections. SCBG increased its collection from about 4,500 taxa in 2002 to more than 10,000 in 2006. WBG increased its ex situ collection from about 4,000 taxa in 2002 to about 8,000 today.
At the same time, a large number of specialized collections have been renovated and enhanced for botanical research and germplasm assessment. The most well known examples include SCBG holding the world largest collection of Magnoliaceae with >130 species, Zingiberaceae with >120 species, Palmae with 382 species and China’s largest collection of bamboo with >200 species; WBG holds the world largest collections of Actinidia with > 52 species and aquatic plants with >800 taxa.
These core botanic gardens have become important centers in China for the conservation of strategically important plant resources. With their species conservation standards aligned to those of other international first-class botanic gardens, these core gardens also provide an important platform to support social and economic sustainable development in China.
Status of ex situ collections in China
China’s botanic garden collections are extensive and representative of the different native flora across the regions of China. Indeed most botanic gardens have focused their collection and conservation work on the local flora or regional flora. However, the need for duplication of ex situ conserved plants across different gardens is also recognized as an important insurance policy to safeguard unpredictable losses. Of the 24,667 plants cultivated ex situ in the 10 main botanic gardens, 8,216 species (33.3%) are duplicated in at least in one other botanic garden, with 15.1% replicated in two gardens, 7.3% in three gardens, and 4.5% in four gardens. However, a total of 16,451 species (two thirds of the total) are not duplicated in any of the 10 main gardens.
However, when considering the duplication rates of species on a garden-by-garden basis, the percentage of duplicated species ranges from 40% to 75%, with an average of 61.3% duplication. The percentage of species from each garden that are duplicated across the 10 botanic gardens ranges from 6% to 20%, with an average value of 11%.
Given that gardens have a focus on conserving local species, duplication at other gardens within the same region should also be treated as a priority, allowing plants to be duplicated in gardens with similar climates and environments. An assessment of such regional duplication reveals that duplication within each region ranges from 10% to 27%.
Conservation of rare and threatened plants
Conservation of rare and threatened plants has been prioritized by Chinese botanic gardens. While in situ conservation cannot save all threatened or rare plants, ex situ conservation offers an effective supplementary conservation activity (Hawkins et al. 2008). Work towards ensuring the ex situ conservation of rare and threatened plants is guided by GSPC Target 8: “60% of threatened plant species in accessible ex situ collections, preferably in the country of origin, and 10% of them included in recovery and restoration programmes”. Significant progresses has been made by botanic gardens in China and it is estimated that all 388 species categorized for national protection (Fu, 1992) are included in the ex situ living collections of botanic gardens. However, extensive collection has not taken place for the 4,404 plant species included on a more recently published Red List (Wang & Xie, 2004) as this list is not widely accepted or finalized by the Chinese government conservation agencies.
Each of the 10 main botanical gardens currently holds between 26 and 710 rare and threatened plants, accounting for an average 8.7% of their total ex situ living collections. Together these collections include 1,633 species, accounting for 37.6% of the 4,404 plants in the recent Red List. Further gap analysis and re-evaluation of ex situ conservation strategies are still urgently needed to ensure that these collections act as a true safety net for endangered species.
A significant feature of the ex situ conservation of threatened plants in the botanic gardens is a high duplication rate across different gardens. The duplication of these species across the 10 main botanical gardens ranges from 57.7% at Turpan Botanical Garden to 95.1% at Nanjing Botanical Garden, with an average value of 79.8%. This provides a good measure of safeguard against unpredictable losses. The duplication within the same region also provides a safe backup at the regional level across China.
When individual taxa are considered, 874 (53%) of the rare or threatened species maintained in botanic gardens collections have been backed up in at least one other garden. Gap analyses is now required to identify selected groups of plant to be collected with a focus on strengthening existing collections and planning for the restoration of key species (BGCI, 2007).
While prioritization of ex situ living collections continues to be important, wide-scale seed banking efforts are also given priority, particularly in the face of climate change, where virtually all species may be at risk. The construction of national seed banks is therefore complementing the ex situ living plant collections. For example, the China Southwest Wildlife Germplasm Genebank project, operated by the Kunming Institute of Botany, CAS, at the end of 2009 included 31,199 accessions from 4,781 plant species belonging to 1,337 genera and 166 families. The goal of the genebank is to seed bank a total of 100,000 accessions from 10,000 plant species by 2020.
In relation to crop diversity, the need for ex situ conservation of diverse crop material has also been recognized as increasingly urgent – with a particular need to focus on crop wild relatives and local varieties of crops as a rich source of adaptive traits for extreme abiotic conditions. The Ministry of Agriculture has established a network of cold storage seedbanks to safely conserve crop genetic resources. These seedbanks, which possess long-term, medium-term and duplicate cold storage facilities, now include 390,000 accessions of seeds of crop germplasm belonging to 450 species, 160 genera and 28 families. In addition, 32 national field germplasm repositories designated for perennial and vegetatively propagated crops, mostly for fruit & nut crops and their wild relatives, include more than 1,300 species of rare and endangered plants (MEP 2008). These efforts have greatly enhanced the ex situ conservation capacity of crop diversity for food security.
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South China Botanical Garden