Taijiang National Park stands out for its wetland ecology, history, and culture. Besides the famous black-faced spoonbills, the park is abound with plant life which includes many precious and rare plant species native to Taiwan. In 2019, Professor Tsung-Hsin Hsieh of National Tainan University carried out a detailed study inventorying plant species in the Taijiang area and discovered 16 local rare plants which were listed in the Red List of Vascular Plants of Taiwan, 2017. Professor Tsung emphasized that the study, conservation, and restoration of these species ought to be strengthened. The 16 species of native, rare plants in Taijiang National Park are:
- Vigna adenantha (wild pea)
- Scaevola hainanensis
- Asian colubrina (latherleaf)
- Digitaria heterantha (fingergrass)
- Aquilaria sinensis (agarwood, milky mangrove)
- Caesalpinia bonduc (L.) Roxb. (Nicker Nut Caealpinia)
- Ipomoea imperati (beach morning-glory)
- Ipomoea polymorpha Roem. & Schult. (morning glory; silky cow-vine)
- Pluchea pteropoda Hemsl.(mangrove)
- Cyclosorus interruptus (swamp shield-fern)
- Lumnitzera racemosa (white-flowered black mangrove)
- Ipomoea violacea (beach moonflower; sea moonflower)
- Eulophia graminea (Chinese crown orchid)
- Tribulus taiwanensis (Taiwanese puncture vine)
- Chloris formosana (Honda) Keng (windmill grass)
- Peplidium maritimum (L. f.) Asch.
These rare plants became endangered primarily due to intensive land development and utilization which resulted in the destruction of their original habitats, making it difficult for them to survive and reproduce in the wild. In addition, widespread alien/invasive plant species at low land elevations in Taiwan compete with these native/rare plants, causing them to gradually dwindle. Some examples include:
- Scaevola hainanensis: At present, an area smaller than 1 ha in a seaside cemetery in Tainan City is the only remaining habitat of this rare plant. When this location is developed or converted to other uses, the Scaevola hainanensis will lose its only habitat and become extinct.
- Asian Colubrina (latherleaf): This rare plant grows on seashore gravel, which is nowadays close to coastal cement embankments. Latherleafs, which are seriously affected by human activity and dike barriers, are facing much difficulties reproducing and thriving.
- Caesalpinia bonduc (L.) Roxb. (Nicker Nut Caealpinia): Its coastal habitat is vulnerable to the impact from seawater. Cement embankments also prevent the expansion of these nicker nuts, resulting in narrow and fragmented habitats.
- Ipomoea imperati (beach morning-glory): In the Taijiang area, this plant is only found in the sandy lands outside the windbreak forest embankment of Chengxi Village. After several incidents such as waste soil dumping and mechanical land preparation, only one plant remains alive in the site.
To conserve Taiwan's rare plants, the Taiwan Forestry Research Institute (Council of Agriculture) has launched the National Botanical Garden Ark Project to carry out ex situ conservation and in situ conservation of local, rare plants which fall under 989 plant species designated as ‘threatened’ on the Red List of Vascular Plants of Taiwan, 2017.
For this reason, the Taijiang National Park Management Office commissioned Professor Ching-An Chiu and his National Chung Hsing University team to execute the Taijiang National Park Native Plant Appropriate Landscape Development Demonstration Project. Under this project, Taijiang Garden will construct a seaside botanical garden which has diverse species, multi-layered planting, and aesthetic landscaping to both restore rare native plants and carry out conservation, education, and recreation in Taijiang Garden.
At the initial project stages, the research team selected 99 species to be planted in Taijiang Garden, of which include 16 abovementioned rare plants. During the process of investigating and recording the habitats of these rare plants, their habitats were analyzed to understand the plants’ reproduction methods and living conditions, so that the principle of Planting the Right Species in the Right Place can be adhered to in Taijiang Garden.
Over two years of research, the team carefully mapped factors such as suitability to humans (carry out species conservation and environmental education, Fig. 1), land (adapt to the local environment), species (select species suitable for humans and the land), seedlings (collect seeds and cultivate robust and beautiful seedlings, Fig. 2), time (plant at the right season), methods (planting with the right methods), and maintenance (easy maintenance and management after planting). Based on these factors, 15 local rare species were collected for cultivation in Taijiang Garden, and fourteen of these species, including Cowpea, Scaevola hainanensis, Asian Colubrina (latherleaf), Caesalpinia bonduc (L.) Roxb. (Nicker Nut Caealpinia), Ipomoea imperati (beach morning-glory) (Fig. 3), have been successively cultivated.
Today, many of these rare plants, such as Scaevola hainanensis planted in the mangrove area A and in the salt marsh area, latherleaf in the coastal sandy land (Fig. 4), nicker nuts in mangrove area B, beach morning-glory on the sandy lands, and the mangrove species Pluchea pteropoda in the salty swamp (Fig. 5) are thriving, blooming, and bearing fruit. All these plants have successfully integrated into the coastal environment of the Taijiang River, their numbers stably increasing as they co-exist and thrive amidst the local flora and fauna (Fig. 6).
The Taijiang National Park Management Office, which is in charge of conservation, education, and recreation, may have previously paid little attention to some rare plants. We are now actively taking action to make Taijiang Garden an ‘ark’ or safe haven for rare plants where these plants enjoy permanent protection and conservation (Fig. 7) and thus reproduce generation after generation hence displaying their vitality and beauty!