Geographic distribution patterns and status assessment of threatened plants in China

Abstract

Large scale heterogeneous distribution of biodiversity has become a hot topic for ecologists and conservationists. A threat status assessment combined with geographic distribution patterns of threatened plants in China has been conducted at a national scale in this study based upon a distribution database that refers to both specimen records and published references. Currently, 302 threatened plant species are cataloged in the “National Protected Key Wild Plants” in China belonging to 92 families and 194 genera. Results of the assessment according to the Categories and Criteria system of The World Conservation Union (IUCN) Red List indicate that three species have been assessed as Extinct in Wild (EW) while a further 79, 99 and 112 species have been assessed as Critically Endangered (CR), Endangered (EN), and Vulnerable (VU), respectively. Distribution patterns of threatened plants were analyzed with GIS to identify areas of high species diversity. It was found that threatened plant species occur unevenly within counties and are concentrated in the following eight hotspots: the central and southern Hengduanshan mountain area; the southeast regions of Yunnan as well as Xishuangbanna and southwestern Guangxi; the southern Hainan island; the border mountainous regions of Guizhou, Hunan and Guangxi provinces; the mountainous regions of southwestern Hubei and northern Hunan; southwestern Zhejiang and western Fujian; central Sichuan and southern Gansu; and the western mountains of Guangdong. Moreover, the 12 counties with the greatest number of threatened plant species represent cumulatively more than 50% of the total listed species and, therefore, are the regions in China that should be prioritized for conservation efforts. By overlapping the map of threatened plant species with the distribution of national nature reserves, a gap was identified in protected areas. This research will ultimately provide insights for prioritizing biodiversity conservation as well as processing the mechanisms of distribution patterns.

Appendix

The eight “hotspots” are described in detail in the Appendix, including locations, topography, climate, main ecosystems, endemic species, etc.

The following describes the eight “hotspots” in detail:

I. Central and southern Hengduanshan mountainous area

The area is located in eastern Tibet and northwestern Yunnan Province. It includes Gongshan and Deqin county in Yunnan as well as Motuo and Chayu county in Tibet. The region is characterized by extremely complex topography with very high steep mountains and low valleys. The main chine of the mountains is approximately 5,000 m, the lowest elevation at 1,500 m and relative height difference approximately 3,000 m. It is a low latitude plateau monsoon climate that also experiences some characteristics of mountainous climates; consequently, the flora of the area has qualities of both northern and southern regions as well as the old and new taxa. The vertical distribution of the vegetation in this area is very clear. The main ecosystem types are evergreen broad-leaved forest, deciduous broad-leaved forest, evergreen coniferous forest, deciduous coniferous forest, alpine shrub, and alpine meadow. The species endemic to this region are Cephalotaxus lanceolata, Neopicrorhiza scrophulariiflora, Pseudotsuga forrestii, and Torreya fargesii var. yunnanensis.

II. Xishuangbanna region, southeastern Yunnan and southwestern Guangxi

The area includes the Xishuangbanna prefecture, Pingbian, Jingping, Xichou, Malipo, Maguan, and Hekou county in Yunnan Province and Longzhou, Napo, Jingxi, and Baise county in Guangxi Province. The elevation in the northern region is higher than in the south. The main topography is a mix of mountainous and plateau areas. It is a tropical monsoon climate without typhoon events. Due to the Indian Ocean monsoon and the Pacific Ocean monsoon in the south combined with the mountains in the north, it developed into the area with the most abundant vegetation and complex flora types. The main ecosystem types are tropical rainforest, tropical monsoon forest, subtropical evergreen broad-leaved forest, deciduous broad-leaved forest, temperate coniferous forest, and tropical montane mossy evergreen broad-leaved forest. The species endemic to this region are Alsophila austro-yunnanensis, Amentotaxus yunnanensis, Amomum petaloideum, Archangiopteris henryi, Caryota urens, Craigia yunnanensis, Cycas balansae, Cycas micholitzii, Cycas multipinnata, Cycas pectinata, Deutzianthus tonkinensis, Dipterocarpus retusus, Dipteronia dyerana, Dipteronia dyerana, Erythropsis kwangsiensis, Etlingera yunnanense, Excentrodendron hsienmu, Hopea chinensis, Hopea mollissima, Horsfieldia tetratepala, Illicium difengpi, Malania oleifera, Manglietia grandis, Manglietia hebecarpa, Manglietia megaphylla, Manglietiastrum sinicum, Myristica yunnanensis, Nyssa yunnanensis, Paramichelia baillonii, Parashorea chinensis, Parepigynum funingense, Pinus wangii, Pterospermum menglunense, Siliquamomum tonkinense, and Vatica guangxiensis.

III. Southern Hainan island

The area includes Baoting, Qiongzhong, Dongfang, Sanya, Ledong, Changjiang, and Lingshui county in Hainan Province. A tropical humid monsoon climate dominates the area possessing characteristics of an ocean climate with an average annual rainfall of 1600 mm to 2500 mm and average annual temperature of 23–25°C. Typhoons occur in this region. The topography in the area possesses qualities of both mountainous regions and valleys with the highest elevation at 1,867 m on Wuzhishan Mountain. The main ecosystem types are tropical montane rainforest, tropical evergreen monsoon forest, tropical semi-deciduous monsoon forest, summit mossy forest, and savannas. The species endemic to this region are Alseodaphne hainanensis, Chunia bucklandioides, Cycas hainanensis, Dalbergia odorifera, Firmiana hainanensis, Heritiera parvifolia, Hopea hainanensis, Keteleeria hainanensis, Madhuca hainanensis, Plectocomia microstachys, Sindora glabra, and Vatica mangachapoi.

IV. Border mountains of Guizhou, Guangxi and Hunan provinces

The area is located in the southeastern Yungui Plateau that includes Libo, Rongjiang, Congjiang, Leishan and Liping county in Guizhou Province, Longsheng, Lingui and Rongshui county in Guangxi Province and Xinning county in Hunan Province. The climate features both subtropical monsoon and mountainous climates. A portion of the area is characterized by Karst topography. The main ecosystem types in the region include evergreen broad-leaved forest, coniferous and broad-leaved mixed forest, and montane elfin forest. The species endemic to this region are Abies beshanzuensis var. ziyuanensis, Abies yuanbaoshanensis, Cathaya argyrophylla, and Keteleeria pubescens.

V. Mountainous area of southwestern Hubei and northern Hunan

The area includes Lichuan, Badong, Xingshan, Shennongjia, Hefeng, and Enshi county in Hubei Province and Sangzhi county in Hunan Province. It lies between the Dabashan and Wulingshan mountains, with extremely complex topography and interlaced hills and river systems. The climate is northern subtropical monsoon with various horizontal and vertical distribution zones. Climatic and topographic conditions result in complex flora and rich biodiversity hosting many relic and endemic plant species. The main ecosystem types are evergreen and deciduous broadleaved mixed forest, evergreen coniferous, subalpine shrubland, and meadows. The species endemic to this region are Sinojackia xylocarpa and Triaenophora rupestris.

VI. Southwestern Zhejiang and western Fujian

The area includes Suichang, Longquan, Qingyuan, and Lin’an county in Zhejiang Province and Wuyishan, Jianning, and Changting county in Fujian Province. The climate is a typical subtropical humid monsoon climate while the topography in the area is very complex. Forest vegetation in the region belongs to the central subtropical evergreen broad-leaved forest. The species endemic to this region are Abies beshanzuensis, Acer yangjuechi, Ginkgo biloba, Heptacodium miconioides, Kirengeshoma palmate, Ostrya rehderiana, Phoebe chekiangensis, Platycrater arguta, and Torreya jackii.

VII. Central Sichuan and southern Gansu

The area includes E’meishan, Baoxing and Tianquan county in Sichuan Province as well as Wenxian and Kangxian county in Gansu Province. The climate is characteristic of the transitional band between the northern subtropical zone and the warm temperate zone. Vertical distribution of rainfall and temperature is very uneven; thus, the vertical vegetation spectrum is very clear, including broad-leaved forest, coniferous forest, alpine shrubland, and alpine meadow. The species endemic to this region are Acer catalpifolium, Cupressus chengiana, Cycas szechuanensis, Cystoathyrium chinense, Kingdonia uniflora, Larix mastersiana, and Parakmeria omeiensis.

VIII. Western mountains of Guangdong

This area includes Lianzhou, Ruyuan, Lechang, Yangchun, Fengkai, and Yingde county in Guangdong Province. The climate is subtropical monsoon being at the boundary between the climates in southern and central China. Elevation is above 1,000 m and the major ecosystem types include subtropical evergreen broad-leaved forest, evergreen coniferous and broad-leaved mixed forest, montane elfin forest, coniferous forest, and alpine shrubland. The species endemic to this region are Dunnia sinensis, Manglietia pachyphylla, and Primulina tabacum.