An Investigation on the Present Situation of Wild Rhododendron Resources and Its Tourism Development and Utilization in Panxi Area

: Panxi region is an important origin and distribution center of wild Rhododendron spp., which has important ornamental and tourism development value. This study investigated the present situation of wild Rhododendron resources in Sichuan Province, and analyzed the species number, horizontal distribution, vertical distribution, correlation with existing scenic spots and traffic accessibility, and put forward the prospect and suggestions of making full use of the rich wild Rhododendron resources in Panxi area for tourism development and boosting rural revitalization.


Introduction
Rhododendron spp. is a large genus with the most species and characteristics in Ericaceae. There are about 967 species in the world, including 8 subgenera [1] and about 570 species in China, belonging to 6 subgenera, 10 groups and 49 subgroups (Fang Mingyuan et al., 2005), which are distributed everywhere except Xinjiang and Ningxia. Because of its cold resistance, it is mainly distributed in the middle and high mountain areas of northwest Yunnan, southeast Tibet and southwest Sichuan. Rhododendron has important economic value. [2] Rhododendron is one of the world's four largest alpine flowers and one of China's ten famous flowers, with high ornamental value and garden application value. Rhododendron contains ketone chemicals and volatile oil, which has antibacterial, antiinflammatory, antitussive, antiasthmatic and expectorant effects. It can treat many diseases and it has very important medicinal value. Rhododendron plants mostly grow on dry ridges, hilltops or cliffs, which are barren and droughtresistant, with dense branches and developed roots, and often clump into impenetrable shrubbery, which can maintain water and soil and have high ecological utilization value.
Panxi region is located in the southwest of Sichuan Province, on the eastern edge of Hengduan Mountains, and consists of Panzhihua City and Liangshan Prefecture, which are composed of 3 districts, 2 cities (county-level cities) and 17 counties. This area is the core area of the resource "Golden Triangle" in Southwest China, which is known as "plant kingdom" and "biological gene bank". Panxi region takes subtropical climate as the base band and south subtropical climate as the main one, with abundant sunshine, abundant rainfall, distinct dry and wet seasons, small annual temperature difference and large daily temperature difference. In winter, it is sunny and dry due to the sinking of the south branch of westerly wind. In summer, it is rainy and humid under the influence of southwest monsoon. The area is rich in heat, with annual sunshine hours of 2300 ~ 2800 h, annual total solar radiation of 580 ~ 630 KJ/cm and frost-free period of over 300d. The annual average temperature is 17.5 ~ 21.0℃, and the temperature difference between day and night is 13.1 ~ 14.4℃. The annual rainfall is 800～1200 mm. There are high mountains and deep valleys in Panxi area, and the relative height difference of canyons is about 3000 m. The special geographical environment of "one mountain is divided into four seasons, ten miles are different days" and the unique conditions of "sunshine in the north of China, temperature in the south and climate in the Indian Ocean" have bred abundant wild Rhododendron germplasm resources in Panxi area, making Panxi area an important origin and distribution center of wild Rhododendron plants.

Historical data collation
The Chinese flora, illustrations of Chinese higher plants, papers related to the species and distribution of Rhododendron resources in Panxi area were consulted, and the historical distribution data of Rhododendron plants in Panxi area were obtained and summarized through Chinese virtual herbarium (http://www.cvh.ac.cn/).

Field survey statistics
From April 2016 to June 2020, the project team conducted a field investigation on the species and distribution of wild Rhododendron in Panxi area, collected samples and registered the species identification, and analyzed the floristic geographical distribution and ecological causes of wild Rhododendron in Panxi area.

Vertical distribution
According to the vertical distribution statistics, wild Rhododendron plants in Panxi area are distributed in the range of 1000-4500 m above sea level, and the altitude difference reaches 3300 m. The vertical distribution of each species is quite different, and the species richness generally shows a trend of increasing first and then decreasing with the altitude. 2200-4000m above sea level is the vertical section where the species of this genus are concentrated, with the highest species richness, including 60 species, 4 varieties and 1 subspecies. From the altitude distribution range of each species, the distribution range of Rhododendron cosmetology is the largest, ranging from 1300 to 4000 m, with a vertical height difference of 2700 m; Secondly, Rhododendron axillaris distributed in the range of 1500-3800 m, with a vertical height difference of 2300 m; The distribution range of Rhododendron Miyi is relatively narrow, and it is only found at 1700 m above sea level at present. The altitude distribution of wild Rhododendron species in Panxi area is shown in Figure 2.

Geographical spatial distribution and traffic accessibility
According to the geographical spatial distribution of wild Rhododendron plants, they are distributed in all counties and cities in Panxi area except the eastern, western and Renhe districts of Panzhihua. Among them, the number of wild Rhododendron species in the north of Panxi area is small, and it is found in the field investigation that most of them are scattered and less concentrated. There are abundant species of wild Rhododendron in the eastern, western and southern regions, especially in Yanyuan and Xichang in the west and midwest, Huili in the south, and Meigu and Leibo counties (cities) in the east. In the field investigation, it is found that the concentrated contiguous distribution is very obvious, which is highly ornamental in full bloom and has good tourism development value. From the correlation with the existing scenic spots, at present, the most famous scenic spots in Panxi area are Lugu Lake Scenic Area and Qionghai-Lushan Scenic Area. Yanyuan County, where Lugu Lake Scenic Area is located, and Xichang City, where Qionghai-Lushan Scenic Area is located, both belong to the areas with the largest number of species and the most obvious concentrated contiguous distribution, which lay a good foundation for the development of tourism resources. From the point of view of geographical spatial distribution and traffic accessibility, because wild azaleas are distributed in the fractured terrain areas with high altitude, complex and varied topography and large fluctuation, subways and expressways will deliberately avoid the fractured terrain areas due to construction requirements, so neither railways nor expressways directly reach the wild azaleas landscape areas with good tourism development value. Xichang City, which has the best traffic conditions, has a small economic service radius, and its radiation driving ability can only radiate to two rhododendron landscape areas, namely Zhaojue Qiliba and Puge Haikou Ranch, which attract the most tourists at present. Therefore, traffic accessibility is a major constraint factor in the development of tourism resources. See fig. 3 for the geographical spatial distribution of wild rhododendrons in Panxi area.  Industrial prosperity is the key to rural revitalization. One of the effective ways to achieve industrial prosperity in Panxi area is to develop rural tourism by using rich wild azalea resources in combination with local natural landscape and ethnic customs, cultivate new rural formats and models, activate the endogenous driving force of rural development, and promote the "trinity" development of rural production, life and ecology. However, on the one hand, to develop rural tourism, the first priority is to attract tourists. Therefore, traffic accessibility is very important for the development and utilization of wild azalea tourism resources. At present, the eight azalea natural landscape groups with good development value mentioned above are only accessible by national or provincial roads, and it needs a long distance of township roads to reach the core landscape area. Therefore, in order to realize the economic development and utilization of wild rhododendron resources in Panxi area, it is necessary to further transform the traffic environment in Panxi area, strengthen infrastructure construction and improve traffic accessibility.
On the other hand, the flowering period of wild Rhododendron is mainly from May to July, and the ornamental value is poor outside the flowering period. Therefore, it is very important to use the existing traffic and scenic spots to establish landscape belts and extend the tourism value chain. In tourism development, other natural and cultural scenic spots around scenic spots can be integrated to create a landscape group integrating ethnic minorities' cultural customs and natural landscapes, enhance the agglomeration of regional tourism elements, and realize the effective development and utilization of tourism resources featuring wild Rhododendron plant resources in Panxi Plateau. Qionghai-Lushan Scenic Area is one of the most well-known scenic spots in Liangshan Prefecture. Besides, as it is located in the suburb of Xichang City. The regional economic radiation radius is stronger than other scenic spots. The Luoji Mountain Scenic Area and Huanglian Soil Forest Scenic Area around the scenic spot can integrate Zhaojue Qiliba Rhododendron Landscape with Puge Haikou Ranch Rhododendron Landscape, enhance the gathering of regional tourism elements, create natural landscape groups, enhance the visibility of the landscape and attract more adult traffic; Lugu Lake Scenic Area can integrate Houlongshan and Huangcao Rhododendron landscape in Yanyuan County and Chajin Rhododendron landscape in mana, Muli County, and establish Lugu Lake-Houlongshan in Yanyuan County and Huangcao-mana Chajin landscape belt in Muli County, so as to integrate Rhododendron viewing, Lugu Lake natural scenery and Yi-Tibetan ethnic customs experience, improve tourism quality and extend industrial chain. At the same time, special attention should be paid to the scarcity of wild Rhododendron resources, which cannot be recovered once destroyed. Therefore, the development of wild Rhododendron resources as tourism resources must be comprehensively utilized under the premise of protection.