Introduction

National Parks in the world grow various useful bio-resources owing to its well-preserved natural plant ecosystem. For residents living within a national park, these resources become materials for medicine, food, clothing, and other purposes. The relationship between the natural conservation of a national park and the life of its residents is interconnected [1].

Also, the traditional knowledge regarding the bio-resources of residents living in a national park affects the natural conservation of an ecosystem [2]. Among all knowledge, the traditional knowledge of food and medicinal plants causes negative effects to plant ecosystems because of its applicability. Particularly, the additional value of medicinal plants is a major concern for species possessing high efficacy and utility as they are potentially overused and supplies become rapidly depleted [3]. These trends are stronger in developing countries with poor health care systems than in developed countries [4].

From this point, the analysis and investigation of traditional knowledge for medicinal plants used by residents in a national park will be applied for a sustainable conservation plan for a natural plant ecosystem.

Research in this field has been widely accomplished in several countries around the world, including Europe [5, 6], Africa [7, 8], Asia [9, 10], North America [11], and South America [12]. The results of this research have been utilized as basic data to formulate a sustainable conservation plan for natural plant ecosystems within a national park.

In Korea, the research of the same pattern has been only conducted from residents living in Hallasan National Park [13].

The natural plant ecosystem of Gayasan National Park, located in the southeast region of Korea has been well preserved. Residents have maintained a traditional culture for over 30 years. These residents have utilized various ethnomedicine for treating numerous ailments. Therefore, a balance between medicinal plants and their utilization plays a very important role to sustain the natural conservation of a national park.

This study aims to investigate and analyze the traditional knowledge of medicinal plants used by residents in Gayasan National Park in order to obtain basic data regarding the sustainable conservation of its natural plant ecosystem.

Research area and methods

Climate and geography of Gayasan National Park

The study area is located in the center of the southern region of Korea and lies between 35° 45′N to 35° 51′N latitude and 128° 02′ 30″E to 128° 09′ 30″E longitude (Figure 1). The study area measures 77.256 km2 in areas including two provinces, one city, and four counties in its administrative district [14]. The annual average temperature is 13°C and the annual average precipitation is approximately 1,275.6 mm [15].

Figure 1
figure 1

Investigation sites.

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Investigative method

Proper data was collected using participatory observations and in-depth interviews, as the informants also become investigators themselves through attending informal meetings, open and group discussions, and overt observations with semi-structured questionnaires [16, 17].

The content of the semi-structured questionnaires was composed of diverse information about medicinal plants, including local names, plant-parts used, ailments, methods of preparation, manufacturing and administration, dosage, and the usable duration regarding each curable formula [17–19].

All plant specimens were collected during their flowering or fruiting seasons and were organized utilizing the normal specimen manufacturing method [18, 20]. The voucher specimens were deposited for preservation in the herbarium of Jeonju University. The precise identification of plants mentioned by the informants was performed in accordance with Lee [21] and Lee [22]. Scientific names of plants were confirmed by the National Knowledge and Information System for Biological Species [23] of Korea.

Quantitative analysis

Informant consensus factor (ICF)

The ICF was used to analyze the agreement degree of the informants’ knowledge about each category of ailments [24, 25]. The ICF was calculated using the following formula:

ICF= nur – nt / nur – 1 ,

where nur stands for the number of use reports of informants for a particular illness category, and nt is the number of species used by all informants for a particular illness.

Fidelity level (FL)

The FL was employed to determine the most important plant species used for treating certain diseases by the local herbal practitioners and elderly people living in the study area [17, 20, 26]. The FL was calculated using the following formula:

FL % =Np×100/N,

where Np is the number of informants that mentioned the specific plant species used to treat certain ailments, and N is the total number of the informants who utilized the plants as medicine for treating any given ailment.

Inter-network analysis (INA)

The INA considers the results of the interrelationship among each individual of a community instead of focusing on the independent characteristics of an individual within the community. The INA has been applied within communities for various ethnographical problems, including ethnogenesis [27] and obesity [28–30].

However, the INA has yet to be applied to traditional medicinal knowledge, although it has been included in relation to its ethnographical properties.

Therefore, this research has newly applied this method in order to attain more network information between categories of ailments and medicinal plants within communities in Korea. The results of the INA were analyzed using UCINET (Ver. 6.460) and NetDraw (Ver. 2.125) software [31, 32].

Results and discussion

Demographic characteristics of the informants

Field investigations were conducted from May 2012 to October 2012. All 208 key informants (28 men and 180 women) were randomly selected at 54 sites, which included community halls, the senior welfare centers, and the traditional markets. The average age of the informants was 77 years of age, with a range in age from 52 to 93, with residents living more than 30 years in the study area (Table 1).

Table 1 Demographic characteristics
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Ethnomedicinal knowledge

In total, 200 species of vascular plants belonging to 168 genera and 87 families were utilized traditionally in 1,682 ethnomedicianal practices.

The species numbers from the Gayasan National Park were similar to those of other communities from previous research, including the communities of the western region of Jeolla North Province (183 species), the southern mountainous region (217 species) of Korea, and Hallasan National Park [13, 16, 19]. These results conclude that people living in the communities in and around Gayasan National Park possess similar application abilities for ethnomedicinal knowledge with other communities in Korea. Also, the number of species recorded in Gayasan National Park occupied 36.9% of the flora (542 species) in the study area [15]. This high percentage means that all medicinal plants collected by residents may negatively affect the conservation of a natural plant ecosystem.

Regarding the number of species in their families and the percentage of the number of times mentioned from the our current investigations, 13 species of Rosaceae occupied 6.5% of the total species mentioned, followed by 12 species of Asteraceae, 11 species of Poaceae, and 9 species of Fabaceae, which occupied 5.5%, 4.5% and 4.0% of the whole, respectively. Generally, these four families contain many more medicinal species than any other family. This data is similar to results obtained within national parks of other countries, including Pollino National Park in Italy [5], Kibale National Park in Uganda [8], Ben En National Park in Vietnam [9], Cumbres de Monterrey National Park in Mexico [11], and Isiboro-Secure National Park in Bolivia [12].

Our overall analysis reveals that 27 plant-parts were selected as medicinal materials. Stems were the most frequently used plant-parts, constituting 25.7% of the whole followed by roots (22.7%), fruits (12.9%), whole parts (7.3%), seeds (5.3%), and other sections of the plant. These results were similar to data obtained in Korea for the western region of Jeolla North Province [19], the southern mountainous regions [16], and Hallasan National Park [13].

The results revealed 51 modes of preparation for the medicinal materials. The percentages for the main modes of preparation were as follows: infusions (32.1%), sweet drinks made from fermented rice (20.1%), brewings (9.3%), macerations (7.1%), and juices (6.8%). Oral administration accounted for 84.8% of all applications, while topical application totaled 15.2%.

Among the medicinal plants mentioned more than 50 times, with certain species used to treat numerous ailments, Hordeum vulgare var. hexastichon (L.) Asch. was used to treat 36 ailments, followed by Artemisia princeps Pamp. in treating 24 ailments, and Zanthoxylum schinifolium Siebold. & Zucc. for treating 11 ailments. One area of major concern is the over application of the Artemisia princeps Pamp. and Zanthoxylum schinifolium Siebold. & Zucc. which can easily lead to its extinction within the plant ecosystem.

Ethno-veterinary knowledge

The medicinal plants for ethno-veterinary treatments were recorded as 15 families, 22 genera, and 23 species that displayed 38 ethnomedicinal practices (Table 2). Among the veterinary medicinal plants, the whole part of Artemisia princeps Pamp., Papaver somniferum L., Picrasma quassioides (D.Don) Benn., Sanguisorba officinalis L., and Poria cocos Wolf were used most often to treat bovine diarrhea. Particularly, Ipomoea batatas (L.) Lam., Ricinus communis L., and Zanthoxylum schinifolium Siebold. & Zucc. were ingested for particular pig ailments, while Lageneria leucantha Rushy was generally used for treating a bovine disease caused by a loss of appetite.

Table 2 Plant species for medicinal purposes in community of Gayasan National Park in Korea
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At present, these veterinary species do not affect the natural plant ecosystem of a national park anymore, as residents use a modern system of veterinary medicine to treat the diseases of domestic animals.

Quantitative analysis

ICF

The ICF ranges from 0 to 1, where increasing values of this factor indicate a higher rate of informant consensus among the illness category.

The category with the highest degree of consensus from the informants was muscular-skeletal disorders (0.98). The ranking followed with remarks from informants related to concerns of pain (0.97), respiratory system disorders (0.97), liver complaints (0.97), and cuts and wounds (0.96). The lowest degree of consensus was birth-related disorders (Table 3). These results expose the fact that the residents living in a national park work in dry-field farming and laboriously gather products from the forests as they live in the mountainous region.

Table 3 Category of ailments and their informant consensus factor (ICF) according to Heinrich et al.[24]
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Medicinal plants for treating disease with a higher degree of consensus can easily be harvested for treating medical ailments. As a result, the natural plant ecosystem of a national park may be partly destroyed in the near future. Therefore, through further study, proper steps to determine a wise alternative to protect them need to be considered.

FL

The FL is useful for identifying the key informants’ most preferred species in use for treating certain ailments. The FL values in this study varied from 1.0% to 100%. Generally, the FL of 100% for a specific plant indicates that all of the use-reports mentioned the same plant for specific treatment [33].

This study classified 57 species of plants with a FL of 100%, even without considering plants that were mentioned only once for better accuracy (Table 3). This information reveals that the informants had a tendency to rely on one specific plant species for treating one specific ailment than for several different ailments. These species possess a much higher potential for being gathered in Gayasan National Park.

Special attention for species conservation within the national park was given to important species (N, Np) with a FL above 100%, regarding the viewpoint of the number of times mentioned and the consensus level for the specific ailment, like Solanum nigram L. (68, 68) in being used for burns, Fallopia japonica (Houtt.) RonseDecr. for pollakiuria (60, 60), Colocassia esculenta (L.) Schott (15, 15) for sterility, Euonymus sachalinensis (F. Schmidt) Maxim. (13, 13) for hemorrhoids, and Staphylea bumalda DC. (13, 13) for facial nerve paralysis (Table 2).

INA between categories of ailments and medicinal plants

INA has originally analyzed social phenomenon and its trends through the network of components [34]. Our research has attempted to analyze the interrelationship between aliments and medicinal plants recorded within these communities.In relation to the network of ailments and medicinal plants, the position of the ailments is distributed into four main groups, where each circle represents four different groups of ailments (Figure 2).Accordingly, the first group is positioned in the upper section of Figure 2 and consists of poisonings, respiratory system disorders, others, inflammation and so on.

Figure 2
figure 2

The network relationship of ailments and plant species.

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The second group is located in the bottom left section and consists of nervous system disorders, gastrointestinal disorders, cuts and wounds, and pains. This group of disorders will require a deeper analysis in order to determine the overlapping use of medicinal species for these ailments.

The third group is positioned on the left side and consists of birth-related disorders and genitourinary system disorders. These results depict that the same medicinal plants used for treating birth related disorders and genitourinary system disorders have a close relationship.

Finally, the circulatory system disorders are the fourth group and are positioned in the bottom section.

Conclusion

These days, the natural conservation of a national park has focused strongly to preserve bio-resources, which are regarded as vital to its environment. However, the natural conservation of a national park is practically determined by the interrelationship between the bio-resources and its utilization by residents.

In relation to this point, this study contains a major focus to obtain the basic data regarding the natural conservation of a plant ecosystem, through the analysis and investigation of traditional knowledge for medicinal plants being used by residents of Gayasan National Park.

Conclusions regarding the preservation of a sustainable natural plant ecosystem within a national park obtained the following results:

First, the high percentage of medicinal plants among flora means that the total amount of medicinal plants gathered by residents may negatively affect the conservation of a natural plant ecosystem within a national park. In order to conserve the plant ecosystem, residents need an adaptable health care system for treating their ailments, instead of relying solely on ethnomedicinal therapies.

Second, residents mentioned quite often that they used medicinal plants to treat their own medical conditions. Therefore, it is necessary to prepare a plan of action for conserving the popular medicinal plants.

Third, medicinal plants for treating the category of disease with a higher degree of consensus can be actively harvested for treating medical problems. The over collecting of these medicinal plants will disrupt the plant ecosystem of Gayasan National Park in the near future.

Fourth, 57 species of plants with a FL of 100% possess a much higher potential for being gathered in the region and it is vital to protect the overuse of these medicinal plants.

Fifth, the results of INA will provide an appropriate plan for the sustainable preservation of a national park through continued study.

Therefore, these particular species need to be conserved for a balanced plant ecosystem within the park.

Consequently, through further study using these results, proper steps need to be established for preparing a wise alternative to create a sustainable natural plant ecosystem for Gayasan National Park and other national parks.