South Tyrol as a hotspot of traditional medicinal plants
Our study explores the local pharmacopoeia of South Tyrol, a region which has thus far been poorly investigated in ethnopharmacological studies when compared to neighboring regions [53–55].
Herbs dominate South Tyrolian medicinal species, followed by woody species. Ferns, mushrooms and lichens are less frequently used (Appendix C). Woody species have a higher overall use versatility when compared to herbs (Fig. 5F) which is related to the variety of plant parts used such as leaves, bark, roots or flowers.
Similar to other studies on traditional medicinal plant use (e.g. Appendix. A [22,23]), the South Tyrolian species are predominately cosmopolitan, only 20% are alpine (Table 4). Biogeographically, 16 of the 20 most cited plants are also found in other parts of Europe, while four grew only in alpine areas. 35% of the medicinal species are classified as threatened or protected species (Table 3). In general, non-protected species are of higher importance for medicinal or veterinarian use than protected species (Fig. 4E). Cultivated medicinal species are dominant and thus, in contrast to other more pristine mountain regions (e.g. [56] in Himalaya or [57] in Ethiopian Highlands), overexploitation is not a current issue in South Tyrol. This has also been reported for other regions with long phytomedicinal traditions (e.g [58] from Central China or [59] from the Balkan Mountains). However, extinction processes due to overharvesting may already have run their course in the Alps. Medicinal species that are currently in use mainly grow in the bottom of valleys rather than at high alpine zones [22].
12% of all South Tyrolean species are used in traditional folk medicine. This proportion ranks among the highest in the European alpine regions and is similar to the Basque country and the neighboring Swiss region of Prättigau. The proportion is twice as high as in the Albanian Alps (Table 6). The ethnobotanicy index for South Tyrol is higher than in other mountain regions of Italy and demonstrates a broad local knowledge of medicinal species. Thus, despite land use changes and industrialization processes, local ethnopharmacological heritage is still being preserved among elders and inhabitants of rural areas (e.g. [31]) and in popular science books (Appendix A). South Tyrol's EI is similar to the global average value for medicinal plants (12%) see [60].
A high number of vernacular names for medicinal species underlines that popular knowledge of medicinal plants in South Tyrol is still well consolidated (Fig.3; Appendix B). However, the generally lower IE values in some regions (Table 5) may indicate a more rapid process of cultural erosion and a loss of ethnopharmacological knowledge [61,62]. Ethnobotanical studies on wild and cultivated plants used as food and medicine by the other ethnic minority in the Alps reported, that traditional knowledge on plant names and uses was limited to the older generations (Appendix, [22,23]).
When estimated by the rarely used ethnophytonomic index (EPI 0.10), popular knowledge of wild species is widespread, exceeds the previously reported value for Sondrio (0.06; [3]), and is comparable to the Central Alps (0.10; [54]).
Table 5: Overview of various ethnobotanical studies of mountain regions in Europe. MP = Medicinal plants; (EI) = Ethnobotanicity index
Reference
|
Country / Region
|
Study area
|
Number of species
|
EI
|
Source
|
|
|
|
Total flora
|
MP
|
|
|
[61]
|
Central- southern Italy (Molise)
|
378 km²
|
ca. 800
|
70
|
6.0 %
|
54 Informants
|
[63]
|
Eastern Italian Alps (Friuli- Venezia Giulia)
|
5,700 km²
|
ca. 3335
|
177
|
5.3 %
|
n.d. Informants
|
[53]
|
Western Italian Alps (Liguria)
|
86 km²
|
ca. 1500
|
105
|
7.0 %
|
65 Informants
|
[54]
|
Northern Italian Alps (Lombardy)
|
896 km²
|
ca. 2185
|
184
|
8.4 %
|
328 Informants
|
Present Study
|
Northern Italian Alps (South Tyrol)
|
7,400 km²
|
ca. 2169
|
275
|
12.0 %
|
17 Literature sources (a.o. 81 informants in [31])
|
[48]
|
North-west Spain (Basque Country)
|
802 km²
|
ca. 1133
|
139
|
12.3 %
|
207 Informants
|
[64]
|
Albanian Alps (Kosovo)
|
3,500 km²
|
ca. 1609
|
98
|
6.1 %
|
91 Informants
|
[65]
|
Eastern Switzerland (Prättigau)
|
610 km²
|
ca. 1414
|
204
|
14.4 %
|
91 Informants
|
By comparing the 20 most cited plants with those that had the most vernacular names, we can observe two general trends. Firstly, 10 of the most cited plants were not among the top 20 plants with the most vernacular names but they have become popular nowadays, e.g. Matricaria chamomilla, Plantago lanceolata, Rosa canina, and Urtica dioica. The high popularity of these species in the region may be attributed to the fact that they appear in most phytotherapy books. Secondly, the 20 plants with the most vernacular names include a higher number of alpine plants (7), which is typical for the alpine environment of the study area, e.g. Carlina acaulis, Leontopodium nivale, and Peucedanum ostruthium. The count of local names is more likely to reflect the original medicinal plants, whereas the most cited plants probably also represent modern plants adapted by knowledge transfer, i.e. neighbors, books, and seminars. Thus, the list of plants with the most vernacular names may be the better scale for evaluating the traditional importance of a plant (Fig.3 and Appendix B and C).
The high number of vernacular names per species (Appendix B) also illustrates the linguistic diversity of our study area, which is represented by the three official languages: German, Italian, and Ladin and manifold local dialects [66]. Overall, the findings from both indices reinforce the assumption that is highlighted in the ethnobotanical survey from [22], that traditional ethnobotanical knowledge is prevalent and well documented in the popular literature while the number of traditionally used species in the area is high.
Established herbal pharmacopoeias conserve local knowledge on medicinal species and function as profound repositories for buried knowledge that is currently assisting the revitalization of natural medicine. As a concequence, a variety of drugs that are derived from plants that were known to ancient civilizations and used throughout the millennia are today being included in modern pharmacotherapy [67].
Our analysis revealed that the use and subsequent abandonment of 17 species in South Tyrol is not linked to new pharmacological or phytochemical evidence on potential negative health effects or due to species conservation measures (protection or Red List status, Fig.5). Moreover, there is limited scientific evidence on medicinal effects. Only 41% of the species, namely the most frequently cited species, have been explored by pharmacological studies in terms of their effects (Fig.4).
Considering the most frequent families to which the medicinal plants belong (Asteraceae, Rosaceae, and Lamiaceae), our results were in high accordance with similar studies in European Alpine areas [3,53–55]. The dominance of Asteraceae in local pharmacological literature worldwide has hitherto been emphasized (e.g. [68,69]). With regard to the most frequently quoted species, there was a general agreement between our results and other studies from Northern Italy. In particular, the species Achillea moschata, Achillea millefolium, Arnica montana, Urtica dioica, and Thymus pulegioides were highly valued throughout all regions [3,53–55,70]. Interestingly, the third most cited plant, Plantago lanceolata, was used only rarely or not at all in other northern Italian regions. Instead, the closely related P. major is used, which, while morphologically distinct, has similar medicinal properties [3,55,70]. Also, the two frequently cited plants, Equisetum arvense and Juniperus communis, appeared to be of minor importance in other northern Italian regions.
We observed a high overall use versatility in South Tyrol (Fig.3). As was reported in other alpine areas [53,54,70], in South Tyrol the most frequent therapeutic uses, and the uses that accounted for the highest number of plants, were for digestive, respiratory and integumentary systems (Table 2).
The majority (59%) of native South Tyrolean medicinal plants remain understudied by medicine and pharmacology. However, considering the success rate (> 70%) of previously investigated plants (111) for which the traditional uses have been validated (79) we get an idea of the large unlocked phytotherapeutic and economic potential of as yet unexplored plants. In particular, the healing properties of the following largely unexplored plants should be analyzed, i.e. the highly quoted species Peucedanum ostruthium (wound healing, anti-inflammatory, digestive, and respiratory properties), Juniperus communis (antiseptic and for genitourinary problems), Alchemilla sp. and Achillea sp. (gynecology), Allium ursinum (cardiovascular, skin, digestion, and respiration), Campanula rotundifolia (borreliosis), Dryopteris filix-mas (antirheumatic and wound healing), Euphrasia sp. (antibacterial and anti-inflammatory for eye and respiration), Geranium robertianum (genitourinary, wound healing and infertility), Larix decidua (wound healing and disinfectant), Pinus mugo (expectorant), Sempervivum tectorum (wound healing), Stachys sylvatica (wound-healing and digestion), and Veronica officinalis (respiration, digestion and musculoskeletal). A few almost exclusive uses were also found in the study area that, to our knowledge, have not been documented before in other Alpine areas. An example of an undocumented plant is of the Geranium robertianum, the flower and leaves of which are used in a tea to help with fertility issues [71]. Another is the use of Botrychium lunaria as an abortifacient [72].
Our results revealed a strong association between food and medicinal uses of the plants, including 128 aromatic or food related species (46.5% of all mentioned species) from over 50 families (Table 1). The most beneficial effects were on digestive, respiratory, skin, and general and unspecific disorders (Table 2). In fact, considering the increasing importance attributed to nutrition on human health maintenance, both therapeutic or prophylactic [73,74], these plants could be of high relevance for the development of nutraceuticals [20]. This may be of particular interest to local sustainability projects that focus on local foods, eco-gastronomy, and organic farming. Examples include juice made from Sambucus nigra berries with antiviral and antimicrobial effects [75,76], jam made out of Rosa canina fruits as a supplement of vitamin C [77], or Thymus sp. as spice with antibacterial effects [78]. Further research is needed to determine the nutritional and chemical compounds as well as safety for the commercialization of these exceptional food sources.
Traditional medicinal plants for the conservation of nature and cultural heritage
For some years, there has been an emerging interest in the use of traditional ethnobotanical knowledge and plant resources [60]. While in the past, medicinal plants were mainly used for home consumption, the cultivation and use of medicinal plants has become a growing market niche in South Tyrol in the last few decades . We recorded at least 21 farms where the main income source was herb production [79], and several gastronomy and hotel businesses that offered seasonal dishes or wellness and recreation programs based on traditional plants and practices [80]. In fact, the commercial use of herbal plants seems to offer numerous positive effects for the economic and ecological sustainability of South Tyrol, i.e. i) the diversification of agricultural production, ii) the maintenance of rural economies, iii) the establishment of local value chains, iv) the preservation of traditional land-use types (e.g., larch meadows or semi-arid grasslands; [81]) through extensive and ecologically oriented farming systems, v) the maintenance of an important source of food supply for insects, and vi) the preservation and revitalization of local identities, with a likely positive effect on biodiversity conservation.
Considering the positive market prospects for herbal products, with annual growth rates between 8–15 % in Europe, North America, and Asia [82], traditional knowledge and plant resources offer a support for local economies. In this context, the various edible and medicinal plants identified in this study could provide opportunities for further diversification of mountain agriculture. Nevertheless, traditional medicinal plants still lack recognition as an economic factor in South Tyrol. Therefore, further research on agro-ecology, nutrition, bioactivity, and safety are highly important for the commercialization of tradition medicinal plants [21].
Many medicinal plants in the study area were threatened by anthropogenic and natural factors. Our analysis showed that 238 of the medicinal plant species (86%) were abundant, whereas 24 species (9%) were very rare and placed under the category of “conservation concern” on the regional Red List [29] (Table 4). Land-use changes, overexploitation, and climate change are considered to be the most serious threats to medicinal plants in Alpine regions [2,19,60]. Biodiversity in the Alps is closely linked to the interaction between the natural environment and traditional human practices [33]. The changes in social, touristic, and agricultural systems in the last decades led to a substantial conversion of land-use systems. This includes the intensification of land use in easily accessible areas [83] as well as the abandonment of traditional practices in remote areas that results in a decrease of species diversity and abundance [81,84]. Consequently, along with the decrease in biodiversity, the abundance of medicinal plants is also affected [6]. In South Tyrol, the abandonment of alpine meadows and pastures along with the related expansion of areas of shrubs and trees has led to a decline of several heliophilous grassland species such as Arnica montana and Centaurium erythraea [85]. Moreover, many medicinal plants (e.g. Carlina acaulis, Gentiana acaulis, Anemone vernalis) that flourish in poor soils have been affected by increased nutrient input caused by fertilization [81].
Unsustainable exploitation of wild collected species is a well-known effect of booming markets with rising demands [60]. In addition, for South Tyrol, an increasing pressure on wild species has been reported by T. Wilhalm (pers. comm., Sept. 24, 2019). However, a closer look at the life forms and plant parts harvested, reveals that not all species are equally affected by collection pressure. Root harvesting as a common practice in South Tyrol can be a severe threat to some rare medicinal plant species. Among root-harvested plants, we identified 6 particularly endangered species, three of which are under protection, two that are unprotected (Dipsacus fullonum and Althaea officinalis), and one species (Eryngium campestre) that is already extinct (Table 4). These threatened but unprotected plants should be re-considered and introduced into the South Tyrolean legislation.
Global warming and the associated upward migration of vegetation has become a major threat to specialized Alpine plants, particular those that inhabit the alpine-nivale altitudinal zones (> 2600 m a.s.l.) [22,86]. Based on the GLORIA project data set, [22] concluded that for South Tyrol, with its highest peaks at almost 4,000 m a.s.l., most plants can continue to invade higher elevations and, thus, the risk of extinction seems to be low. However, [22] identified two species (Artemisia genipi and Primula glutinosa) that are restricted to the upper Alpine zone and therefore might not be able to migrate further upward. Based on the same methodology, but with a larger data set, we identified at least 10 additional medicinal plant species that are restricted to the upper Alpine zone and therefore might be endangered by warming, at least locally (Table 5). In the foreseeable future, this could be the case in the Sella/Latemar region, for example, or the Texel group where the highest summits do not exceed 3,200 m and the elevation distance between upper alpine and highest summit is less than 600 m a.s.l. On the other hand, however, some endangered medicinal plants such as the thermophilous species Marrubium vulgare may also benefit from warming.