Wild edible plants collected and consumed by the locals in Daqinggou, Inner Mongolia, China

Background Knowledge of wild edible plants is an important part of traditional knowledge. It is closely related to traditional human agriculture, as well as biodiversity. This study aimed to conduct a detailed investigation and evaluation of wild edible plants that are collected and consumed by the Mongolian and Han locals in Daqinggou and to provide valuable data for the development and utilization of plant resources. Methods In the 9 site visits to the area of Daqinggou during the period of 2017–2019, the authors used key informant interviews, semistructured interviews, and questionnaires to collect utilization information regarding precollected species of local wild edible plants. By combining the data obtained from 101 key informants, the authors used the Cultural Food Significance Index (CFSI), a quantitative index to evaluate the relative importance of the wild edible plants that were discussed in the aforementioned interviews. Results The investigation results show that the Mongolian people provided 67 folk names, corresponding to 57 wild plants, and the Han Chinese provided 58 folk names, corresponding to 49 wild plants. A total of 61 edible wild plant species belonging to 29 families and 52 genera were recorded as edible resources for the locals in Daqinggou. The uses include grains, oil and fat resources, vegetables, fruits, beverages, condiments, and snacks. The most commonly reported purpose of wild edible plants is using them as vegetables, followed by using them as beverages and fruits. The most widely used edible parts are fruits, leaves, and other aerial parts. Eating raw and cooked plants are the usual methods of consuming wild edible plants according to the locals. In addition, the CFSI of 61 wild edible plant species shows that 27 species have characteristics of medical food. Conclusions The knowledge and experience of naming and consuming wild plants by the Mongolian people and Han Chinese in Daqinggou are an important manifestation of the direct interaction between locals and plants. The CSFI evaluation of the wild edible plants consumed by the locals in Daqinggou establishes the utilization of some wild plants as part of the traditional knowledge of medical food.


Background
Since 1992, as party to the Convention on Biological Diversity (CBD), China has made positive efforts in the protection and inheritance of traditional knowledge related to biological diversity and biological resources. The diversity of traditional edible plant resources and related knowledge are important aspects of traditional knowledge and biodiversity. They have a significant impact on the conservation and sustainable development of regional biodiversity [1][2][3][4][5][6]. As most kinds of edible plants are wild plants, research on wild edible plants is also an important subject of ethnobotanical study [7].
Wild edible plant species are uncultivated and undomesticated. They can be food sources, however, through collection and consumption from the natural environment. Many linguistic groups refer to numerous edible plants as "famine relief food," which plays an important role in the survival of individuals or the whole community during a period of food shortage [8]. In recent years, wild edible plants have become popular for their nutritional value and health care functions [9]. Therefore, the utilization of wild edible plants is continuously increasing. The ethnobotany research in China concerning wild edible plants has so far been concentrated mainly in South China. For example, the Naxi people, Hani people, and Tibetan people in Yunnan Province have the habit of gathering and eating wild plants [10][11][12]. The Shui people and Dong people of Guizhou Province have recorded the use of wild plants as starters for preparing fermented beverages [13,14]. Although some papers on the use of wild food plants have been published from the area of northern China (e.g., Inner Mongolia [15,16], Tibet [17], Shaanxi [18,19], and Gansu [20,21]), this area is not widely studied.
The Inner Mongolia Autonomous Region is multiethnic, with Mongolian culture as the main body and Han Chinese as the majority. Since the 1990s, ethnobotanists have carried out a series of studies on regional ethnobotany in several regions of Inner Mongolia and have cataloged the wild edible plants of the local Mongolian people [15,16,[22][23][24]. In the past, ethnobotanical studies in Inner Mongolia have not been performed with comparative studies between Mongolian people and Han Chinese. This study investigates the Mongolian people and Han Chinese in Daqinggou and records the wild edible plants and related traditional knowledge that locals have previously used and are currently using.       Daqinggou is a national nature reserve of precious broad-leaved mixed forests, with a population of nearly 800. Locals are engaged in semifarming, semianimal husbandry, or tourism. It is a mixed area of Mongolian people and Han Chinese, with a large Mongolian population, all of whom speak Chinese. Daqinggou is located 24 km southwest of Horqin Left Wing Rear Banner, Tongliao City, Inner Mongolia Autonomous Region, longitude 120°1 3′-122°15′, north latitude 42°45′-42°48′ (Fig. 1), with a total area of 81.83 km 2 and a forest area of 45.95 km 2 . The landform consists of sand dunes, sandy land and plains belonging to the subsidence zone of the Liaohe River Basin [25]. According to the "climatic regionalization of China," it is in the transition zone from the Northeast temperate semihumid climate zone to the Inner Mongolia temperate semiarid climate zone, with an average annual temperature of 5.6°C and mean annual rainfall of approximately 450 mm. The length of the frostfree period in the area is approximately 145 days [26].
The flora mainly consists of the flora of Changbai Mountain and Mongolian, combining the species of North China flora [27]. A total of 104 families, 320 genera, and 528 species of vascular plants grow in Daqinggou. Among them, 13 species belong to 10 different families of ferns, 3 species belong to 3 different families of gymnosperms, and 511 species belong to 91 different families of angiosperms [28].

Field work
From 2017 to 2019, the authors completed 7 field studies in Daqinggou; there are two villages within the reserve and five villages in the surrounding area. Field studies included key informant interviews (Fig. 2), semistructured interviews, and questionnaires. Local farmers, retailers, and reserve staff were selected as the informants, and 227 people were interviewed. A total of 101 key informants participated in the interviews via selection using snowball sampling and intentional sampling [7,[29][30][31][32]. The ages of informants ranged from 24 to 88 (mean age 58 years), and the gender and ethnic ratios of informants were both almost 1:

Voucher specimen
Ethnobotanical interviews and the collection of voucher specimens were carried out in two ways: locals were invited to find and collect voucher specimens of related plants at the field sites; voucher specimens were precollected and used in key informant interviews [23,33]. A total of 84 plant specimens were aggregated as wild edible plants used by the locals. Among the collected specimens, 57 species, 3 varieties, and 1 form were identified [34,35].

Ethnobotanical inventory
There are 61 species of wild plants consumed by local people. Among them, 1 species belongs to pteridophyta, 1 species belongs to gymnosperms, and 59 species belong to 27 different families of angiosperms. This paper is summarized in the form of an ethnobotanical inventory to facilitate the analysis and evaluation. The contents of the inventory include the scientific names of species, folk Chinese and Mongolian names, usage, edible part(s) and mode of consumption, linguistic groups, and voucher numbers ( Table 2).

Life form characteristics of wild edible plants
The life forms of wild edible plants used by the locals are small trees, trees, shrubs, subshrubs, lianas, annual herbs, and perennial herbs. Among them, 26 species are perennial herbs and account for 43% of the total species; 12 species are annual herbs, and 11 species are trees, accounting for 20% and 18%, respectively, of the total species. Daqinggou is a part of the steppe of Eurasia. Because of the plant distribution in the reserve, it is closely related to the broad-leaved forest of East Asia [27]. Therefore, woody plants also account for a certain proportion in this area.

Food categories
The usage of wild edible plants by locals presents high diversity. According to their eating habits, food categories include grains, oils and fats, vegetables, fruits, beverages, condiments and snacks. There are 84 kinds of related plants corresponding to different usages, which is more than the total number of edible plant species, because some of the same plants have different usages (Table 3).
Among them, the wild plants used as vegetables are the most abundant. Grains were gathered and consumed during times of food shortage and famine. At present, only the bark of Ulmus pumila is dried and ground into flour, which is appropriately added to corn flour to increase its strength. In fact, this is a traditional way of using vegetable gum.
There are three consumption modes of wild beverage plants: Locals collect different parts of the wild plants for processing and making tea; some elders also soak the roots or fruits of wild plants in wine to make medicinal wine for drinking; Quercus mongolica and Vitis amurensis are used to make wine. Most of the wild fruits mentioned above are eaten by shepherds as snacks to satisfy hunger and thirst.

Edible part(s) and mode of consumption
The edible parts of wild plants consumed by locals also present high diversity. According to statistics, apart from the aerial parts, the edible parts of most species are plant organs and organ combinations such as the root, stem, leaf, flower, fruit and seed, or specific parts such as the bulb, female cone, shoot, and bark. Twelve types are used. The most widely used edible parts are the fruit (17), leaf (16), and aerial parts (12) (Table 4).  Wild edible plants are consumed in two ways, as raw food and as cooked food. The mature fruits and young fruits eaten by locals as fresh fruits and the tender stems and leaves consumed as snacks are raw food. The wild vegetables used by locals for steaming, frying, filling, soup, and seasoning plants are consumed as cooked food.
As the most widely consumed wild plants in the region, there are seven types of traditional wild vegetables (Fig. 3). Wild vegetables are frequently soaked in cold water or blanched in boiling water and then used for stir-frying or soups. For the local Mongolian people, cream is also a commonly used condiment with cooked wild vegetables. In particular, local people like to eat wild vegetables with flour and to add salt, a little oil and wild vegetables into the dough to steam a unique pasta called "bulasu".
Taraxacum mongolicum ranks first in the CFSI, attributed to its high quotation index, multifunctional food use index value and food-medicinal role index value. Its tender stem and leaf can be used as vegetables; flowers and roots can be used for herbal drinks and have the functions of heat clearing. Fagopyrum esculentum ranks last with the CFSI because of the very low frequency of consumption over the past 30 years. Its flowers and a small amount of flour are cooked to satisfy hunger only in the famine years. This reported use only exists in the memory of the elderly.

Wild edible plants used for diet therapy
In addition to their edible function, many wild edible plants also have health care functions, and a wide range of diseases can be prevented and cured by  eating these plants [43][44][45][46][47]. The CFSI of 61 wild edible plant species shows that 27 species have medical food characteristics. The locals use these plants as medicine for the following: rheumatism, diuresis, heat clearing, and tonifying Qi ( Table 6). For example, patients with rheumatism can relieve their pain by drinking the medicinal wine made from the root of Adenophora polyantha and Cerasus humilis. Herbal tea made of Sonchus arvensis can be used for "heat clearing" according to traditional folk knowledge. A snack made from the seeds of Quercus mongolica can treat diarrhea in children (Fig. 5).

Conclusions
A total of 61 species of wild plants are consumed by local people. Among them, Abutilon theophrasti, Fagopyrum esculentum, and Lycium chinense have been reduced to escaped species, common along roadsides and in wasteland and fields. A total of 126 folk names of local wild edible plants were recorded. Among them, the Mongolian people provided 67 folk names, corresponding to 57 wild plants, and the Han Chinese provided 58 folk names, corresponding to 49 wild plants. The corresponding rates of Mongolian and Han folk names and scientific names were 85.07% and 84.48%, respectively, which indicates that scientific knowledge has high consistency with traditional knowledge in botanical nomenclature [48][49][50]. However, the choice of edible parts and consumption between the two linguistic groups was almost identical. Based on the statistics, the most widely eaten parts of wild edible plant species are aerial parts, stems, and leaves. Wild edible plant species are most commonly cooked (as a soup) or eaten fresh.
The CFSI of wild edible plant species was also calculated, with a minimum of 0.04 and a maximum of 10295.63. Taraxacum mongolicum, a local common natural potherb, was the most popular wild edible plant based on its high CFSI metric. According to the corresponding records of Chinese herbs and Mongolian medicine [51][52][53][54][55], among the 27 species of wild diet therapy plants, 19 species were recorded based on Mongolian medicine, and 23 species were recorded based on Chinese herbal medicine. Adenophora remotiflora, Cannabis sativa f. ruderalis, and Salsola collina have not been recorded in the relevant literature. Twelve species have been recorded in the literature of "Chinese Materia Medica: Mongolian Medicine roll", and 23 species have been recorded in the literature of "Planta medica records of Inner Mongolia". This reflects that the locals have high consistency with Mongolian medicine and Chinese herbal medicine in the selection of wild diet therapy plants; 17 species have been recorded in the literature of "Pharmacopoeia of the People's Republic of China", which shows that the knowledge of local wild diet therapy plants has a strong scientific basis and is worth further study.