Introduction

Forests not only are a source of timber products and environmental services but also generate resources that are gathered for artisanal, domestic, industrial and medicinal uses (^{Gutiérrez, 1989}) and have a high social and cultural value for rural communities (^{Campos, 1998}; ^{Conforte, 2000}). The non-timber part of the forest, which refers to the biological materials of nature with the exception of wood (^{Semarnat, 2003}; ^{Zorondo, 2007}), are known by various terms, including Alternative Forest Products, Biological Forest Resources, Non- Timber Goods and Services, Wild Products, Natural Products and Non-Timber Forest Resources (NTFRs) (^{Chandrasekharan, 1995}; ^{FAO, 1999}; ^{Wunder and Angelsen, 2003}). These resources have been collected from ancient times by rural communities and have contributed significantly to their lifestyle and well-being (^{Chandrasekharan et al., 1996}; ^{Ulujobi, 2012}).

Thousands of species worldwide are estimated to be obtained from nature for a variety of purposes (^{Myers, 1988}), particularly for the livelihood of rural populations and, to a lesser extent, for commercial exploitation. In general, they remain in the informal sector because their sale is not registered in a constant, rigorous way ^{(FAO, 1995)}.

In Mexico, the farming families combine agriculture, livestock breeding, small trades and migration with the collection of NTFRs in order to obtain an income, which, although limited, contributes to the everyday diet (^{Pulido et al., 2010}). Due to the diversity of its ecosystems, the state of Oaxaca has a great ethnobotanical tradition that includes the knowledge, use and management of a large number of vegetal species, through complex forms of interactions between the local communities and their environment.

According to the estimates, there are 2 800 useful species of vascular plants; however, these are scarcely documented, despite the wealth of uses of the local flora and of the various forms of interaction between human populations and plants (^{Caballero et al., 2004}).

In order to create a record of these NTFRs -i.e. these wild plants- in two Zapotec communities of the Sierra Juárez of Oaxaca, a list of useful species was generated; their vernacular names in Zapotec, which are part of the traditional knowledge, were researched, and the plants were taxonomically determined.

Materials and Methods

Results

In Capulálpam 122 species were registered, with 177 uses grouped into eight categories; the main species in terms of their number were medicinal (42 %), edible (21 %) and ornamental (19 %), followed by the species used in rituals (9 %), crafts (3 %), forage (3 %), fuel (1 %) and other uses (2 %). Most plants had a single use (64 %); others had two-fold (28 %), three-fold (5 %) and four-fold (3 %) uses.

128 wild plants were identified in Jaltianguis, with 192 uses grouped into 10 categories; the group with the largest number of species was medicinal (43 %), followed by edible (19 %), ornamental (14 %), ritual (10 %), forage (5 %), artisanal (4 %), saponiferous (2 %), fuel (0.5 %), utensils (0.5 %) and other uses (2 %).

In regard to the number of uses per species, 62 % have a single use, 31 % have two uses, 5 % have three, and 2 % have four.

As a whole, 166 wild plants were obtained, of which 84 species (51 %) were mentioned in both locations. The floristic list, with the vernacular and Zapotec names, is shown in Table 1.

Table 1 Floristic list of the main useful non-timber forest resources in Capulálpam de Méndez (C) and Santa María Jaltianguis (J). 

¹ The scientific names and the botanical families correspond to the scientifically accepted names according to: http://www.theplantlist.org/ (September 30, 2015). C = Capulálpam de Méndez; J = Santa María Jaltianguis.

The Zapotec names of the species were not mentioned in Capulálpam, whereas in Jaltianguis 67 % of the plants preserve their Zapotec names, although only a limited group of inhabitants can write them.

Only 2 % (3) of the plants included in the floristic list of Capulálpam remain undetermined and are registered exclusively by their vernacular names (hoja de golpe, hoja guinda and hormiguillo); 29 % (35) were identified at genus level, and 69 % (84), at species level.

Of the list of plants of Jaltianguis, 26 % (33) were identified at genus level, and 74 % (95), at species level. Of the list of plants found in both communities, 30 % (50) were identified by genus, and 68 % (13) by species.

20 NTFRs belonging to the flora of Capulálpam were mentioned by two or more different vernacular names, while 34 NTFRs of Jaltianguis were given two or more names (Table 2).

Table 2 Non-timber forest resources cited under two or more vernacular names in Capulálpam de Méndez and Santa María Jaltianguis, Oaxaca. 

Taxonomical determination and classification of NTFRs

Determination of taxonomical groups: 50 botanical families were found in Capulálpam, the best represented of which were Asteraceae (21), Orchidaceae (16), Leguminosae (8) and Lamiaceae (5), with the largest number of species; the rest of the families include 4 species or less. The list for Jaltianguis grouped 60 botanical families. The largest number of species belonged to the Asteraceae family (20), followed by Orchidaceae (14), Lamiaceae (8) and Leguminosae (6); the rest of the families include 4 species or less. The NTFRs cited in the two locations were grouped in 66 botanical families (Table 3).

Table 3 Botanical families and number of species of useful non-timber forest resources in Capulálpam de Méndez and Santa María Jaltianguis, Oaxaca. 

All species of NTFRs were classified according to ^{García and Meave (2012)} into these categories: native, endemic across Mexico, endemic in Oaxaca, exotic and cultivated. Table 4 shows them arranged according to this classification.

Table 4 Endemic, cultivated and exotic non-timber forest resources registered in Capulálpam de Méndez and Santa María Jaltianguis, Oaxaca. 

Source: ^{García and Meave, 2012}.

Discussion

The floristic list of 122 wild plants of Capulálpam and 128 of Jaltianguis has not been cited for the communities of the Sierra Juárez region. ^{Acosta and Martínez (2013)} registered 48 NTFRs in Santa María Yavesía, and 39 in Santa Catarina Lachatao; both figures are below those obtained in this study. Thus, further efforts to identify and document the useful flora, and the flora in general, must be pursued. This would encourage comparative studies and would allow visualizing conservation priorities for certain resources that are considered to be scarce or endangered as a consequence of various human activities.

Excluding the exotic and cultivated plants that grow wild in the locations of the study, the number of wild plant species regarded as NTFRs from the point of view of forest management planning that were identified in the first location is 12 (91 %); 13 species (88 %) were found in the second location.

As for the categories of use of the registered NTFRs, the highest percentage for the category of medicinal wild plants was 42 % in Capulálpam and 43 % in Jaltianguis, which coincides with the findings of ^{Loredo et al. (2002)}, ^{Monroy and Ayala (2003)}, ^{Padilla (2007)}, ^{Luna and Rendón (2008)} and ^{Molina et al. (2012)}.

In regard to the 51 % species shared between the two communities, although both are located in the same region, due to their geographical location each community has different environmental conditions and, therefore, different diversities of species.

The plant may be known and registered under several common, local or vernacular names, with variations according to the different locations even when they are all within the same region; thus, sometimes two different names were used for the same species (e.g. Equisetum myriochaetum Schltdl. et Cham.), and others, a single name was found to refer to several species (e.g. pine).

On the other hand, ancestral knowledge, specifically of the use of the native language, diminishes drastically with the passage of time and with the implementation of economic and political development programs; for this reason, in Capulálpam, recognized as a “Magic Town” (Pueblo Mágico), the names of the plants in the Zapotec language were not mentioned, whereas 86 names in this language were documented in Jaltianguis. Still, these records surpass those of the study of medicinal plants by ^{Cervantes and Valdés (1990)}, who cite 101 species, of which only 22 are mentioned by their indigenous names. Likewise, in the present study one same name in Zapotec is recorded for different taxa; for example, the term Benáh is used equally for the white maguey, the red-flower maguey and the green maguey (bromeliads), the term Shia-Tziilah refers to the group of orchids, and Diígah tzáh is used for both the blackberry and the sarsaparilla.

This suggests the relevance of implementing research on the local classification systems in order to attain a precise botanical identification and to ensure that reference is being made to the same taxonomical entity (^{Martínez et al., 2015}). This agrees with what ^{Berlin (1992)} calls Folk Taxa -a way of structuring a traditional classification system that includes animals and plants.

The NTFRs registered in the two locations were grouped into 66 botanical families; those with the largest wealth of species were Asteraceae (25), Orchidacea (22), Lamiaceae and Leguminosae (9), Pinaceae (7), Cactaceae (5) and the Agavaceae, Bromeliaceae, Rosaceae and Verbanaceae families (4). These results agree with the floristic diversity recorded by ^{García (2012)} for Oaxaca, who describes the Asteraceae family as the most diverse, with 856 species. At regional level, there is a coincidence with ^{Torres et al. (2009)}, authors who point at the Asteraceae and Orchidaceae families as those with the largest wealth of species, comprising 174 and 104 taxa, respectively.

These values are similar for other regions of the state. ^{Padilla (2007}) documents 107 useful species belonging to 36 families -the best represented of which is Asteraceae, with 18 species (22 %)- in San Pablo Etla. In the Southern Sierra, ^{Luna and Rendón (2008)} registered 555 species belonging to 301 genera and 13 families, 20 of which include 50 % of the useful species; the most prevalent families were Fabaceae, Asteraceae and Solanaceae. In the Mixtec region of the state of Oaxaca, ^{Tapia (2011)} reported 223 species grouped into 79 botainical families, of which Asteraceae (10.7 %) and Cactaceae (5.8 %) are the most prevalent.

Studies carried out in other states of the country with different approaches report the Asteraceae family as the most numerous. ^{Loredo et al. (2002)} , in Michoacán, registered 199 useful species grouped into 153 genera and 68 families, 44 % of which consist of: Asteraceae, with 25 species; Lamiaceae, with 17; Fabaceae, with 1; Rosaceae and Solanaceae, with 10; Fabaceae, with 9, Apiaceae, with 7, and Brassicaceae, with 6.

In the state of Morelos, ^{Monroy and Ayala (2003)} reported 77 species (4 species were not identified by their scientific name), grouped into 42 families, the most outstanding of which were Fabaceae, with 10 species, and Asteraceae, with eight. ^{Hernández et al. (2005)} registered 44 species with medicinal use, belonging to 26 families and 41 genera, in Zapotitlán de las Salinas, Puebla, and found that the Asteraceae family had the largest number of utilized species (20.5 %). ^{Canales et al. (2006)} registered 46 medicinal species in 28 families and 46 genera in Coxcatlán, Puebla; the Asteraceae family had the largest number of recorded species. ^{Lira and Blanckaert (2006)}, in their ethnobotanic study of useful shrubs in Santa María Tecomavaca, registered 37 families, 94 genera and 142 species; the most numerous families were Poaceae, with 22 species; Asteraceae, with 17; Malvaceae with 13; Solanaceae, with 12; Fabaceae, with 1, and Euphorbiaceae, with 10.

In Los Altos de Chiapas, ^{Nepomuceno and Ishiki (2010)} recognized 68 useful species belonging to 30 families and 56 genera; the botanical families with the largest number of species reported were Asteraceae, with nine species; Leguminosae, with eight, and Verbenaceae, with six. In Hidalgo, ^{Molina et al. (2012)} determined 69 plant families, 148 genera and 222 species; the best represented families were Asteraceae and Labiatae. ^{Gómez (2012)} cites 12 medicinal plants, grouped into 57 families, in a village in Tabasco, the most outstanding families being Asteraceae, with 10 species, and Lamiaceae, with 7.

^{White et al. (2013)}, in Estado de México registered 165 species corresponding to 147 genera and 70 families; Asteraceae (18) was the most representative family, followed by Lamiaceae, with 10 species. ^{Villarreal et al. (2014)}, in Malpasito-Huimanguillo, Tabasco, identified 128 medicinal plants, distributed in 63 families, of which the best represented were Asteraceae, with 10 species, and Fabaceae and Lamiaceae, with seven.

According to ^{Suárez and Villaseñor (2011)}, the Astareaceae family stands out for its endemism, as 502 species are endemic across Mexico, and 133, in Oaxaca. There are limited data on the presence of exotic wild plants, of which ^{García and Meave (2012)} registered 308 species in the state.

Conclusions

Sierra Juárez is one of the highest records of useful wild plants.

The interconnection of knowledge between the two communities is evident in it, as they share 51 % of the listed species and traditional lore regarding the uses of wild plants, mostly of medicinal plants.

The fact that 67 % of the plants were registered under an indigenous name shows local resistance to relinquish the use of the native language.

Furthermore, it highlights the importance of carrying out studies on the traditional nomenclature, given the presence of a significant number of plants that are mentioned under several vernacular names each.

The floristic list of NTFRs includes 166 species grouped into 66 botanical families; the families with the largest number of species were Asteraceae, Orchidaceae, Lamiacieae,

Leguminosae, Pinacaceae and Cactaceae.
Eight species of useful plants are endemic across Mexico, two are endemic to Oaxaca, 13 are exotic, and two are cultivated.

Conflict of interests

The authors declare no conflict of interests.

Contribution by author

Joel Martínez López: writing of the Abstract, Introduction, Results, Discussion and Conclusions, as well as support in the methodological framework, field and herbarium work; Alejandra Acosta Ramos: support in field work, identification of species of the Orchidaceae family, construction of tables 2, 3 and 4, collaboration in writing of the Introduction and Discussion sections; Enrique Martínez y Ojeda: writing of the Abstract and help in the herbarium work; Filemón Manzano Méndez: field work, support in the study area section as well as in regard to methodology and discussion.