Parakmeria Omeiensis (Magnoliaceae), a Critically Endangered Plant Species Endemic to South-West China
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Integrated conservation for Parakmeria omeiensis (Magnoliaceae), a Critically Endangered plant species endemic to south-west China D AOPING Y U ,XIANGYING W EN,CEHONG L I ,TIEYI X IONG,QIXIN P ENG X IAOJIE L I ,KONGPING X IE,HONG L IU and H AI R EN Abstract Parakmeria omeiensis is a Critically Endangered tree attractive and large, and their seed arils are orange, making species in the family Magnoliaceae, endemic to south-west the tree an attractive ornamental plant. However, the species China. The tree is functionally dioecious, but little is known has a restricted range. It has been considered a Grade-I about the species’ status in the wild. We investigated the Key-Protected Wild Plant Species in China since and range, population size, age structure, habitat characteristics has been categorized as Critically Endangered on the and threats to P. omeiensis. We located a total of individuals IUCN Red List since (China Expert Workshop, ), in two populations on the steep slopes of Mount Emei, Sichuan the Chinese Higher Plants Red List since (Yin, ), and province, growing under the canopy of evergreen broadleaved the Red List of Magnoliaceae since (Malin et al., ). forest in well-drained gravel soil. A male-biased sex ratio, lack The tree has also been identified as a plant species with an of effective pollinating insects, and habitat destruction result extremely small population (Ren et al., ; State Forestry in low seed set and poor seedling survival in the wild. We Administration of China, ). have adopted an integrated conservation approach, including Parakmeria includes five species (P. nitita, P. lotungensis, strengthening in situ conservation, cultivation of saplings, ex P. kachirachirai, P. yunnanensis and P. omeiensis), distributed situ conservation and reintroduction, to protect this species. throughout south-east and south-west China. All species in The successful conservation of P. omeiensis has important im- the genus have male and perfect flowers on different plants plications for the conservation of the genus Parakmeria and and are thus morphologically androdiecious. The genus is con- the family Magnoliaceae. sidered to represent a transition from bisexual to unisexual flowers (Liu, ;Xu,;Chenetal.,). Androdioecy is Keywords China, Critically Endangered species, cryptic a rare breeding system in angiosperms (Listen et al., ; dioecy, integrated conservation, Magnoliaceae, narrow Fritsch & Rieseberg, ;Pannell,), and some studies distribution, Parakmeria omeiensis, reintroduction have shown that androdiecious flowers are functionally dioe- cious (i.e. cryptic dioecious), with the morphologically perfect flowers being functionally female (Schlessman et al., ; Mayer & Charlesworth, ; Sun et al., ). When the Introduction sex ratio of dioecious species is : in a population, it can maximize seed yield (Lloyd & Webb, ), but sex ratio is he tree species Parakmeria omeiensis (Magnoliaceae) is often male-biased (Mayer & Charlesworth, ). endemic to south-west China. It was described as the T The following factors have been suggested as threats to type species of the genus Parakmeria (Hu & Zheng, ). species of Parakmeria: habitat destruction, logging, a narrow The earliest specimen was collected from Mount Emei in range, low seed yields, low germination rates, and lack of the city of Leshan in Sichuan province. Parakmeria omeiensis protection (Xu, ; Deng et al., ). Improved knowl- is evergreen, can reach – m in height and blooms from edge of the pollination biology and breeding systems of the late April to mid May (Plate ). The flowers are fragrant, genus is required for developing conservation strategies. It has been suggested (Yu et al., ) that in situ conservation DAOPING YU*, CEHONG LI,TIEYI XIONG,QIXIN PENG,XIAOJIE LI and KONGPING XIE should be improved for threatened species with a cryptic Sichuan Provincial Institute of Natural Resource Science, Chengdu, Sichuan, dioecious breeding system, including monitoring plant sur- China, and Emeishan Botanical Garden, Emeishan, Sichuan, China vival and preventing human disturbance, and that these XIANGYING WEN*† and HAI REN (Corresponding author, orcid.org/0000-0002- 3744-8007) Guangdong Provincial Key Laboratory of Applied Botany, South approaches should be coupled with ex situ conservation to China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, maintain genetic diversity for potential reintroductions. China. E-mail [email protected] Individual P. omeiensis trees with perfect hermaphroditic HONG LIU Department of Earth and Environment, International Center for flowers were first found on a steeply sloping ridge of Mount Tropical Botany, Florida International University, Miami, USA Emei at an altitude of , m(Wu&Wu,). We began to *Contributed equally collect seeds from all fruiting female trees of the Biandanyan †Also at: Botanic Gardens Conservation International, Richmond, UK population during –, germinating them at Emeis- Received April . Revision requested July . Accepted August . First published online June . han Botanical Garden and obtaining seedlings. The first Oryx, 2020, 54(4), 460–465 © The Author(s), 2020. Published by Cambridge University Press on behalf of Fauna & Flora International. doi:10.1017/S003060531900111X Downloaded from https://www.cambridge.org/core. IP address: 170.106.35.76, on 01 Oct 2021 at 08:54:09, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S003060531900111X Integrated conservation 461 PLATE 1 The flower (a, b), fruit (c) and an individual of Parakmeria omeiensis (d). individual grew from seed to m high and began flowering Magnolia denudata,fromMarch to March ,asa in May .By, individuals had flowered. propagation experiment. All seedlings were transplanted into Only preliminary studies have been conducted on the nursery bags, with mixed humus and pearlites, at least year associated plant communities (Zhuang et al., ), tissue before they were planted out. We carried out reintroductions culture (Chen & Ma, ; Yu et al., ) and breeding sys- (sensu IUCN, )attwosites(Fig. ): Zhanglaoping is within tems of P. omeiensis (Yu et al., ). Here we provide up- the known range of the species and Xixinsuo is close to dated information on the species’ range and population size, the known range. We reintroduced both grafted female plants investigate population structure and threats to the species, and seedlings of unknown sex. In March of each of –, and develop an integrated conservation strategy. c. individuals were outplanted into evergreen broadleaved forests at ,–, m altitudes on Mt Emei. Methods Results To identify the range of P. omeiensis,wereviewedtheFlora ofChina(Xiaetal.,) and other literature, and examined Range and habitat all specimens of the species in the herbaria of the Chinese – Academy Sciences. We reassessed the populations based on From field surveys and herbarium studies during , data collected during –,confirmingthatallknownP. we found only two populations, km apart, at Biandanyan omeiensis are located on the north-east and north-west slopes ( km ) and Shisungou ( . km ), with a total of asso- of Mt Emei, in south-west Sichuan Province, China (Fig. ). ciated vascular plant species ( tree, shrub, herb During – we recorded the altitude, slope and soil and three vine species). The plant community is a subtrop- type where the species is found. To investigate the size struc- ical evergreen broadleaved forest, with . % of individual ture of P. omeiensis populations, we measured the height, trees being evergreen. The climate is subtropical, with abun- diameter at breast height (DBH, for tree, height . m), dant rain and fog and warm, humid monsoons. The plant and crown area of all plants located. We established three communities in the two areas are similar, dominated by × m plots to survey all tree species and five × m sub- species of the families Magnoliaceae and Lauraceae. The – plots within each plot to survey shrubs and herbs. During canopy is m high, the plant community comprises – we interviewed eight local managers of the Mt one tree layer, one shrub layer and one herb layer, and – Emei Scenic Spot and seven local villagers, to investigate plant cover was %. Parakmeria omeiensis was scat- – – any factors affecting the species. tered within the Michelia martini Neolitsea levinei – In the flowering period (April–May) at Emeishan Lithocarpus cleistocarpus Sinarundinara nitida community – – Botanical Garden during –, flower visiting insects at altitudes of , , m on slopes of °. The were caught and identified. We also carried out bagged pol- average soil pH was . , and soil was well-drained gravel lination experiments using the ex situ population, to assess with . % organic matter, . % nitrogen and . % fruit-set from hand-pollination (cross-pollination with pol- phosphorus. We observed Near Threatened Tibetan rhesus len from a male tree) and self-pollination. As a control treat- monkeys Macaca thibetana frequently; they sometimes ment we used untreated flowers that were accessible to damaged branches and immature fruits of P. omeiensis. natural pollinators. We used flowers for each treatment. Seeds were collected from the Emeishan Botanical Garden Population structure in mid September –, stored in a refrigerator for months and sown in garden soil in March of each of the fol- We found a total of individuals of P. omeiensis in the two lowing years. We grafted P. omeiensis scions to rootstocks of populations: in Biandanyan,