Guizhou Province, located in southwest China, has abundant rainfall and changeable terrain. The special geographical environment has created a suitable environment for plants, and a wide variety of plant resources have also provided abundant food resources to local residents [10]. The results show that, compared with our previous research results on edible wild plant resources in arid areas of northwest China's Loess Plateau (Hassan area), the edible wild plant resources collected in the concentrated areas of the Gelao people in northern Guizhou are much richer in species, edible categories and consumption modes. The Gelao people have rich traditional knowledge of plant identification, medicinal uses and resource protection.

Gelao people’s botanical understanding of edible wild plant resources

Based on long-term experience, the local Gelao people have accumulated a wealth of traditional knowledge on the rich and varied local edible wild plant resources, not only in terms of their use as food but also as medicine. However, regarding the strict classification of plants, the local residents' level of understanding is limited. For some plants with related species, the local residents often collectively call them the name of their edible parts. For example, many plants in the Caprifoliaceae are consumed as honeysuckle, and individuals can only distinguish them based on leaf size, flower length and color. Only the fruit color (red or yellow) can be distinguished among different P. fortuneana (Maxim.) H.L. Li varieties, and the differences among other species are attributed to their differences in light, water and soil nutrient requirements in the growing environment. The tender seedlings of various ferns are collectively called juecai/juetai moss. Some individuals can tell the differences among these ferns, but they are mostly distinguished based on the picking season, taste and so on.

However, not all related plants are treated as the same kind. Although the local residents collectively refer to the fruits of Rubus L. (Rosaceae) as paoer/peier, they have named them different types of “bubble” according to their color, taste and picking season; for example, yellow bubbles and black bubbles are named after their color, and sour bubbles are named after their taste. M. haplocalyx Briq. is a traditional Chinese medicine [23], and M. suaveolens Ehrh. is a close relative that is often used as a fake substitute in traditional Chinese medicine. However, local residents believe that M. suaveolens Ehrh. is the genuine M. haplocalyx Briq., that is, fish coriander, and that M. haplocalyx Briq. is used as the substitute. Pseudocydonia is also divided into two kinds by local residents according to the shape of the fruit: one is elongated and medicinal, whereas the other is round and edible.

Gelao people’s understanding of the medicinal uses of edible wild plant resources

The Gelao people’s understanding of the medicinal function of plants in this area is mainly based on their knowledge of traditional Chinese medicine. Nourishing, heatiness-reducing, appetizing and dampness-eliminating are all descriptions of the efficacy of traditional Chinese medicine [24]. The Gelao people’s description of a plant’s specific medicinal function is also consistent with those of traditional Chinese medicine, but it is relatively much simpler. The heatiness-reducing plants eaten by the Gelao people are generally aimed at inflammatory fever (excessive internal heat) diseases, such as mouth ulcer, gingival inflammation, halitosis, etc., and can also be used to regulate the similar internal heat effects caused by eating spicy hot pot, while plants that can relieve summer heat are mainly used to deal with hot summer weather and prevent heatstroke. In addition, some knowledge comes directly from traditional Chinese medicine or modern medicine. For example, plants whose edible parts are seeds (kernels) are generally considered to have nourishing effects, and the information that Carya cathayensis Sarg. kernels can nourish the brain comes from traditional Chinese medicine [25]. This may be directly related to the fact that T. chinensis (Pilg.) Florin (HongDouShan) contains taxiresinol, a prominent anticancer drug [26]. However, we do not know whether the fruit of T. chinensis can cure cancer.

Gelao people’s knowledge of plant medicinal uses may also be related to the local climate. The region is rich in plant resources that are used as raw materials for fermented foods. These fermented foods include fruit wines, vinegar, sauces, fermented bean curd and fermented beverages. However, due to the influence of industrialization, it is difficult to find Gelao residents who can provide accurate information about fermented foods at present, but we have learned much such information from local supermarkets. In addition, local residents also like to soak fruits in low-alcohol liquor to make fruit wines with various flavors and colors, such as YangMei wine, CiLi wine and FuPenZi wine. In addition to fruit wine, residents in this area also enjoy other types of infused wines. Various plants are soaked in various kinds of wines according to their efficacy in treating diseases, medicinal functions or other special properties. Typical infused wines can be used for dispelling wind and dampness (Gastrodia elata Blume), improving male sexual function (Epimedium borealiguizhouense S. Z. He & Y. K. Yang, R. laevigata Michx.) and to fight cancer (HongDouShan fruit). In most cases, many plant species are mixed and soaked together, and some medicinal wines are soaked with animal medicinal materials.

Some plants that are considered poisonous by modern knowledge are also fully utilized as food by residents of northern Guizhou, the most important of which is the Araceae [27]. Many species of Araceae are called YeMoYu by locals. Solanum tuberosum L. and other Araceae are usually steamed and cooked with potatoes, sweet S. tuberosum L., and Dioscorea, and there is no information about poisonings from the consumption of these plants. This is somewhat similar to eating Aconitum L. plants in some areas of Yunnan [28]. The toxic components in the roots of these plants may be destroyed during high-temperature cooking [29, 30], making the food safe. However, local people also have the habit of eating fresh DuJuanHua. However, we did not obtain any useful information during the study on how they distinguish toxic from nontoxic DuJuanHua. However, information about poisonous mushrooms was mentioned repeatedly, which may be related to the local government's vigorous awareness campaign on the subject. For example, some young children have been taught to sing the following song about poisonous mushrooms: “Red umbrella, white stalk, after eating you’ll be dead…”.

Gelao people’s understanding of resource protection

Among the edible wild plants with CFSI > 500, except Osmunda lancea Thunb., A. elata (Miq.) Seem. and C. bursa-pastoris (L.) Medik., which are rich in resources and are not damaged by eating (young seedlings and leaves are the main edible parts), a large number of plants are cultivated in the courtyards of local residents, such as H. cordata Thunb., M. suaveolens Ehrh., Zingiber striolatum Diels., Lilium brownii F.E.Br. ex Miellez. and Polygonatum sibiricum Delar. ex Redoute. The main purpose of cultivation is to facilitate eating, but it is also an effective protection strategy for these frequently eaten resources.

Local residents also consciously protect some rare plants. For example, the whole plant of G. elata Blume is not dug, and a certain number of provenances will be reserved so that this valuable medicinal and edible plant resource can sustainably provide food for residents. The collection of E. borealiguizhouense S. Z. He & Y. K. Yang has gradually changed from the previous whole-plant digging to the method of collecting leaves and keeping roots. For plants whose roots are eaten, residents basically follow the principle of picking large ones and keeping small ones. At the same time, they will consciously spread the seeds of rare plants to help their population expand, such as Codonopsis radix, T. paniculatum (Jacq.) Gaertn., and L. brownii F.E.Br. ex Miellez. (pearl bud).

Through combining 23 reports which have been published, it is found that the research areas are mainly in Guizhou, Yunnan, Inner mongolia, Gansu, Fujian, Sichuan Province and Tibet. There are 1,912 kinds of edible ethnic plants in these places. Compared with the 151 kinds of wild edible plants collected in Gelao area in northern Guizhou, we have investigated 66 kinds of wild edible plants that have never been published before, such as Youngia japonica (L.) DC., Symphyotrichum subulatum (Michx.) G.L.Nesom, Rubus idaeus L., Rubus coreanus Miq., Nicandra physalodes (L.) Gaertn. and Indocalamus tessellatus (Munro) Keng f., which are mostly local plants of Gelao nationality.

Current status of the Gelao people’s traditional cultural knowledge

Although the informants were mainly Gelao people, we found that there was no considerable difference between the residents belonging to this ethnic group, their Miao and Tujia neighbors, and the local Han people. This differs from the ethnic groups in northern China, such as Tibetans and Mongolians, who have their own characteristics [31, 32]. The traditional cultural knowledge of the Gelao people is basically only displayed in festivals or performances for travelers. Their knowledge of the uses of wild plant resources is no different from that of the local Han people. The 151 species of edible plants cited by the Gelao informants are found in various recipes or other works by the Han people [10, 33]. The ethnic characteristics of the Gelao people have thus basically died out. At the same time, we also found that the amount of information provided by the informants was positively correlated with age. Most young people under the age of 25 only know that there are certain plants that can be eaten, and they have eaten them before, but they know little about the plants and how to prepare them. In 2020, China has lifted the whole people out of poverty and completely solved the food problem of China Chinese people. Wild edible plant resources of ethnic minorities are mainly used as wild vegetables, condiments or tonics, and only a few varieties are gradually domesticated into daily edible vegetables and become supplementary resources to the existing food resources. But at present, the vast majority of them are only inherited as a traditional culture.