Study On Network Optimization Of Endangered Plants Conservation In China

Nowadays, with the development of science and technology as well as the continued increase of the global population, the demand of plant resources is increasing. However, for the diversity of plant resources of China and the complexity of geographical distribution as well as insufficient protection, part of plant resources are in danger situation. Currently, it is urgent to determine the key areas of the endangered plant distribution, to find out the protection gaps, optimize the distribution network, and put forward the effective protection measures. Therefore, based on endangerment category of "critically endangered (CR)", "endangered (EN)" and "Vulnerable (VU)" from the China Species Red list "(Wang et al,2004), this study chosed 3773 species of endangered plants including 166 families as study object. Using Spatial analysis technology of geographic information system (ArcGIS) and Systematic Conservation Planning (SCP) software (C-plan), the irreplaceability value (Ir) of every planning unit (2378 administrative counties)was calculated. The study filtered the area with high protection value, combined the distribution of existing nature reserves to find out the protection gaps and put forward three kinds of optimization schemes of conservation network. Meanwhile, this study calculated the contribution value (Ti) and the conservation efficiency value (C) to assess and compare with the existing nature reserve network and the network after Optimized.The main conclusions are as follows:(1) The quantity of endangered plants is vary distributed in different regions, mountainous area is higher than plains and the southwest area is higher than the northeast area. In this study, the land area of our country was divided into eight major areas:Western Himalayan Mountains, Southwestern Hengduan Mountains, Southern Hainan island, Southeastern Wuyi-Taiwan Mountains, Central Kunlun-Qinling Mountains, Northeast Big and Small Xing’an-Changbai Mountains, Northwestern Altai-Tianshan Mountains, and Northern Qilian-Helan Mountains. The study proved that, the quantity of plants in Southwestern area is the most, which of the northern area is the least.(2) The distribution range of high protection value is descending from the southwest to the Northeast. The area of high value (Sum Ir> 18.88) and relatively high (4.6< Sum Ir<18.88) mainly distributes in southwest and south, including 86 planning units and covers a total area of 433701.09 km2 (4.57% of the study area) while the northwest and northern areas have a relatively low protection value.The results of the irreplaceability analysis indicated that plants of eight wild distribution families of China, including:Orchidaceae, Ericaceae, Theaceae, Lauraceae, Fagaceae, Leguminosae, Aceraceae and Pinaceae are mainly distributed in southwestern China, and Yunnan Province is the most abundant place. The planning units of these eight families with high protection value (0.8≤Ir<1.00) and relatively high protection value (0.60≤Ir<0.80) are respectively 142,57,208,264,197,72,330 and 340.(3) The conservation gaps of plants are mainly distributed in southwestern area. Among them, the first level conservation gap (Sum Ir≥3.00) has 46 planning units, with a total area of 219819.63 km2, mainly distributed in the areas such as Dulong and Nu Autonomous County of Yunnan province and Cuona County of Tibet Autonomous Region. Secondary protection gap (0.45≤Sum Ir<3.00) has 139 planning units, with a total area of 523159.36 km2,mainly distributed in the areas such as Yun County of Yunnan Province and Barkam County of Sichuan Province.(4) Protection efficiency of endangered plants was improved significantly after optimizing the protection network. If the endangered plants of protection gaps are brought into nature reserves,3648 species would achieve the protection goal, which accounting for 96.69% of the protection targets and the protection efficiency would increase to about 95%.(5) Three kinds of protection optimization schemes of endangered plants were proposed. Combined with the human disturbance index and irreplaceability index, this study proposed three kinds of protection optimization schemes:Conservation scheme of conservation value priority:mainly distributed in west, southwest, south, southeast and northeast of China, including 173 planning units, with a total area of 699506.7km2, accounting for 7.36% of the study area. Conservation scheme of rescue priority:mainly distributed in southwest, south and southeast of China, including 73 planning units, with a total area of 186196.6km2, accounting for 1.95% of the study area. Protection scheme of economic avoidance priority:mainly distributed in northwest and southwest of China, including 98 planning units, with a total area of 513310.2km2, accounting for 5.4% of the study area.Finally, according to the above research results, this study put forward a series of protective measures of in situ and ex situ conservation, the aim is to provide theoretical and scientific basis for the protection of endangered plants in China.