Information analysis: uses of the species

The selection of informants was done randomly, seeking representation by gender, age, occupation and place of birth. From the information obtained during the semi-structured interviews, the taxa reported were grouped into 17 categories of use based on ^{Cárdenas et al. (2002}).

where: RQZ: wealth of knowledge that a person has of the useful species, in relation to all the useful species found in the region; EU: number of useful species recorded by a person; Maximum EU Value: total of useful species reported in the region by all the people participating in the study. The value of this index varies from 0 to 1, with 1 being the maximum value of knowledge of the useful biodiversity of the region.

Level of preference towards the species

In order to evaluate the preferences of the inhabitants towards the plants used, the concept of “use value” was used (VU, for initials in Spanish) (^{Philips and Gentry, 1993}). This valuation shows the amount of uses that a specific plant is given. To determine this valuation, interviews were performed with “quality” informants about the names and local uses of the plants; each time an informant indicates a use it is cataloged as an event. The formula is the following:

where: VUis: use value attributed to a specific species (s) by an informant (i); Uis: number of uses mentioned by the informant; Nis: total number of events.

Then, the general use value is obtained with the sum of the use values calculated before:

where VUis: use value attributed to a specific species (s) by an informant (i); Ns: total number of informants interviewed about a specific species (s).

An entity or taxa can be used more than another due to reasons of abundance, preference, or else, it can have more than one application within each category. To capture these variables, the interpretation of use value (VU, for initials in Spanish) used by ^{Prance et al. (1987}) was adopted in this study. It is established that the highest VU of a species for a specific category adopts the value 1, and the lowest VU is 0.5. The total use value of a species was obtained by adding the use values from each category. In order to obtain the VU of the corresponding botanical family, the total VUs of the species were added and divided by the number of species in that family.

Valuation and selection of priority species

With the aim of reaching a consensus concerning which were the categories of use that represented most importance for the local inhabitants, as well as the species of highest appreciation, both for their use value and for the change value, each one of the informants was presented with a list of the names of the categories and plants recorded in the previous stage. This list was accompanied by a format to record and evaluate each one of the species selected according to ^{Peters (1996}) in a matrix that includes variables of social, economic and ecological nature. The valuation was made through the method proposed by ^{Lawless and Heymann (1998}), modified by ^{Martínez-Pérez et al. (2012}), a technique broadly applied in psychology studies and in sensory evaluation panels. However, in contrast with the original technique, for this study the drawing of the straight line was substituted with a valuation scale from 0 to 10. For this purpose, each participant was given a list of the species identified as the most important useful plants in each of the communities, accompanied by a matrix of 12 columns to grade each of the social, economic and ecological variables, as shown in Table 1.

The grades assigned by each informant for each plant and variable were calculated in a scale of 0 to 10. Later, the corresponding averages were calculated from the individual grades of each species and variable. The plants that obtained the highest averages for a specific variable were considered as outstanding for that characteristic. Depending on the number of variables (social, economic or ecological), for which a given plant resulted as outstanding, they were prioritized in: Socioeconomic Valuation: (a) species of highest socioeconomic importance, those that were outstanding in 2-3 social variables and 3-5 economic; (b) those of medium importance, which were outstanding in 1 social variable and 1-2 economic; and (c) those of lowest relevance, which were not outstanding in any variable. Ecological Valuation: (a) Species of highest abundance or highest possibilities of increasing their populations, which were outstanding in 3-5 ecological variables; (b) species of regular abundance, which were outstanding in 1-2 ecological variables, and (c) scarce or threatened species, which were not outstanding in any ecological variable.

Level of knowledge in both communities

The total useful plant species in the communities studied was 156. There is a numerical difference in Alta Cima (total value of 0.75, that is, the users know 75 % of the 156 species identified for the study zone), followed by San José (total value of 0.63) (Table 4).

However, when observing the maximum and minimum values in each locality and the average values, these are similar and there are no significant differences, as was proven when applying the Student’s t-test (Table 5).

Useful species and level of preference. In this study, 156 taxa of useful plants were identified, corresponding to 62 botanical families for Alta Cima and 50 for San José. The most frequent families in both communities were: Labiatae, Rosaceae, Asteraceae and Fabaceae (Table 6).

These 156 species are defined as “key cultural species” (^{Garibaldi and Turner, 2004}; ^{Núñez and Simberloff, 2005}; ^{Del Amo, 2011}), and, therefore, correspond to the “local ethnobotanical heritage” (^{Pardo de Santayana and Gómez-Peyón, 2003}) or to the “local biocultural heritage” (^{Carambula and Ávila, 2013}), key starting point for management plans with aims of use and conservation.

Regarding the specific demand, the useful plants species with highest demand have to do with the supply of specific materials for daily life, whether food v.gr. venadilla o tepehua (Porophyllum ruderale (Jacq.) Cass.) and guava (Pisidium guajava L.). Others are used as medicinal remedies, such as rosemary (Rosmarinus officinalis L.) and elderberry (Sambuscus nigra Schltd. ssp. canadensis (L.) R. Bolli), or else they are quite appreciated for specific uses, such as the wood of the cimarrón walnut (Juglans mollis Engelm.) for handicrafts; berry (Maclura tinctoria (L.) D. Don ex Steud.) and palo de agua (Dendropanax arboreus (L.) Decne. & Planch.) to make poles; or else others are ornament, like maravilla (Mirabilis jalapa (L.) (Table 7).

In contrast to what happens in Alta Cima, in San José the highest demand values were obtained in cultivated species of exogenous origin. This denotes the high cultural importance that these species have acquired for local inhabitants. According to ^{Núñez y Simberloff (2005)}, when exotic species acquire high indexes of importance value, they can act as an obstacle for biological conservation and can even begin to act as invading species that threaten the permanence of native biodiversity. However, we consider that this is not the case and that these species have acquired a “naturalization card”, even becoming part of different cultural manifestations present, since, as ^{Bennett y Prance (2000)} suggest, when ethnobotanical research is done, researchers should not only notice the predominance of exotic plants and justify their results in terms of acculturation processes.

Table 8 presents the demand for the species by category and by community. According to the informants consulted, these categories have played an important role in local life, but the processes of transculturation and the decree of the RBEC transformed the knowledge and role of these types of uses in daily life, which has caused the disuse of several species that belong to these categories, especially those used for timber, toxic ones (particularly for livestock), for coloring, fodder and of veterinary use. Others, on the contrary, have been revalued in recent times, such as those used for handicrafts (in particular for seed necklaces, bracelets and earrings) and for beverage-making (especially homemade fruit liquors). Despite the wealth of species of these categories of use, the results show that these categories with highest percentages seem not to play a main role in the livelihoods developed presently, since the ancestral practices of disease care with medicinal plants have been lost with time, as well as the collection and consumption of wild food species.

Valuation and selection of priority species for conservation and sustainable exploitation

Socioeconomic valuation of wild species. Wild species of greatest socioeconomic importance. These are shown in Table 9. Of these species, magnolia (Magnolia tamaulipana A. Vázquez), smooth-bark Mexican pine (Pinus pseudostrobus Lindl.) and berry (Maclura tinctoria (L.) D. Don ex Steud.), have an aspect of subsistence, but they are quite valued to be reproduced in nursery for reforestation and for their sale as ornamentals. The other species are quite appreciated and managed because they provide cash income, such as palmilla¹(Chamaedorea radicalis Mart.), whose collection constitutes the main source of income for inhabitants in the communities of study; and the others, wild blackberries (Rubus coriifolius Liebm. and Rubus sapidus Schltdl.) and wild grapes (Vitis cinerea (Engelm.) Millardet and V. tiliifolia Humb. & Bonpl. ex Roem. & Schult.), are frequently used in the elaboration of conserves and homemade liquors by local inhabitants, who sell them to tourists that visit the zone. Of these, the first six are the most abundant or with highest capacity to increase their populations according to the perception of local inhabitants, while the last one (berry) was the scarcest naturally in the ecosystems of the communities of study.

Another case is the good valuation made of at least four species of orchids (Encyclia mariae (Ames) W.E. Higgins, Stanhopea tigrina Bateman ex Lindl., Isochilus unilateralis B.L. Rob., Prostechea cochleata (L.) W.E. Higgins and Lycaste deppei (Lodd.) Lindl.), about which there is a manifest interest in reproducing them, even with limited distribution and some being listed as in danger of extinction (Table 9).

Wild plants of medium socioeconomic importance are shown in Table 10. Several of these species have, naturally, scarce populations in the different habitats of the cloud forest, and are mostly appreciated for auto-consumption, whether for construction or for handicrafts, such as the red cedar (Cedrela odorata L.); to build “dead” wood fences, hueso de tigre (Wimmeria concolor Schltdl. & Cham.); as medicine, pohua (Trema micrantha (L.) Blume), aguacatillo (Nectandra salicifolia (Kunth) Nees) and arnica (Pseudogynoxys chenopodioides (Kunth) Cabrera); or as ornamentals, romerillo (Taxus globosa Schltdl.), moquito (Podocarpus matudae Lundell) and arnica (Pseudogynoxys chenopodioides (Kunth) Cabrera). There is a particular interest in increasing the populations through intensive cultivation of red cedar and hueso de tigre, as well as for other species in nurseries for their sale as ornamental plants, such as romerillo, moquito and arnica.

Wild plants of minimal socioeconomic importance. They are shown in Table 11, with some standing out like epazote (Teloxys ambrosioides (L.) W.A. Weber) and juanjilón (Pseudobombax ellipticum (Kunth) Dugand), which are used as condiment and for food, as well as species of venadilla or tepehua (Porophyllum macrocephalum DC. and Porophyllum ruderale (Jacq.) Cass.). There is special interest in reproducing in nurseries the patula or nylon pine (Pinus patula Schltdl. & Cham.) for their sale to the public and for reforestation. For San José, there were no taxa considered in this category.

Ecological valuation of wild species

Wild species with high ecological valuation. Table 12 shows the useful wild species with highest probability of increasing their populations, with the following standing out: wild blackberries (Rubus coriifolius Liebm. and Rubus sapidus Schltdl.), wild grapes (Vitis cinerea (Engelm.) Millardet and Vitis tiliifolia Humb. & Bonpl. ex Schult.), magnolia (Magnolia tamaulipana A. Vázquez), alamillo (Liquidambar styraciflua L.) and palmilla (Chamaedorea radicalis Mart.). It should be noted that these are all characteristic plants of the cloud forest in the RBEC.

Wild plants of medium ecological valuation. Table 13 shows the wild plant species of regular abundance and with medium opportunities of increasing their populations in the communities of study, among others, orchids (Euchile mariae (Ames) Withner, Stanhopea tigrina Bateman ex Lindl., Isochilus unilateralis B.L. Rob., Prostechea cochleata (L.) W.E. Higgins and Lycaste deppei (Lodd.) Lindl.), tejocote cimarrón (Crataegus rosei Eggl.), berry (Maclura tinctoria (L.) D. Don ex Steud.), and red cedar (Cedrela odorata L.).

Wild plants with low ecological valuation. Table 14 shows the wild plant species that are scarce or threatened; among others, romerillo (Taxus globosa Schltdl.), chamalillo (Ceratozamia kuesteriana Regel), monilla or cascabelito (Ungnadia speciosa Endl.), jacubo (Acanthocereus tetragonus (L.) Hummelinck), and hueso de tigre (Wimmeria concolor Schltdl. & Cham.). For San José, no taxa were considered in this category.

Some authors have shown that the status of species conservation is prioritized based on the daily management and interaction of local people with the useful species (Pardo de Santayana and Gómez-Peyón, 2003; Paule and Potvin, 2004; Paredes et al., 2007). Results show that the vegetation provides these communities mainly with basic products (food, medicine and beverages) and for sale (handicrafts and ornamental plants). The use values (VU, for initials in Spanish) show the preference of interview respondents for useful plants in the communities studied, but they are not necessarily related to the importance that these have, as was observed when making the participative socioeconomic and ecological evaluation. The group of plants with the highest socioeconomic value for the inhabitants of the communities of study is integrated, specifically, by five plant species that are vital for their economy and their subsistence in the RBEC. They are: palmilla (Chamaedorea radicalis Mart.), two species of wild blackberries (Rubus coriifolius Liebm. and Rubus sapidus Schltdl.) and two species of wild grapes (Vitis cinerea (Engelm.) Millardet and V. tiliifolia Humb. & Bonpl. ex Roem. & Schult.), and among them there are those that have more possibilities for conservation and recuperation in the perception of local inhabitants. There are also others that are considered apt to be reproduced in community nurseries (for reforestation or sale to the public), such as magnolia (Magnolia tamaulipana A. Vázquez), berry (Maclura tinctoria (L.) D. Don ex Steud.), sacred fir (Abies vejari Martínez), patula or nylon pine (Pinus patula Schltdl. & Cham.) and smooth-bark Mexican pine (Pinus pseudostrobus Lindl.), given their natural scarcity in the zone and/or the probabilities of commercialization as a live plant. Other species of medium and low socioeconomic importance include species with potential in the future, such as jacubo (Acanthocereus tetragonus (L.) Hummelinck), red cedar (Cedrela odorata L.), smooth-bark Mexican pine (Pinus pseudostrobus Lindl.) and patula or nylon pine (Pinus patula Schltdl. & Cham.), which have scarce populations naturally but good opportunities to increase their populations.

There is a marked interest in cultivating intensively some species such as red cedar and wild blackberries, or reproducing in nursery (reforestation or sale to the public) species like magnolia (Magnolia tamaulipana Vázquez), smooth-bark Mexican pine and patula pine. It should be noted that a higher percentage of taxa used as food were identified in San José, especially “quelites”, than in Alta Cima; this can be attributed not only to the fact that it is a more remote community, but also to the ethnic origin of its inhabitants (native and/or descendants of migrants from the states of Michoacán and Estado de México). However, these results can also be attributable to restrictions in the exploitation of timber-yielding and fuel species that were traditionally used and that the local inhabitants knew about (which was the reason of their arrival in the zone), and because there are not roads that are passable all year long, forcing the inhabitants of the RBEC to make a more intensive exploitation of the available and legally allowed resources in the RBEC, particularly non-timber species. This necessarily implies resorting to a higher number of plant species, both for subsistence and for sale, for example for food, to make handcrafts, ornamentals, and for beverages with high demand among visitors to the reserve.

The geographic location of the populations, nestled in a mountainous zone, allows their inhabitants a very close relationship with the surrounding vegetation, since these plants constitute a natural source of staple products, for subsistence, and for the elaboration of products that generate cash income. This generates, in turn, a demand such that can consume any amount of these resources as it is possible to collect in the zone. This condition contributed, to a large extent, to inhabitants participating actively in this study and showing an interest in the development of management programs for those species, with the expectation of attaining socioeconomic benefits. González-Loera and López-Velázquez (1991) mention the medicinal and food species, together with fuel and fodder, as priority in ethnobotanical research in Mexico. However, the fact of identifying few fuel, fodder and timber species in the communities of study can be consequence of the restrictions that were established since the area was declared as protected, as was mentioned earlier. These data agree with the conclusions reached by Hernández-Sandoval et al. (1991) and Luna et al. (2003) in the sense that it is not the diversity, but rather the socioeconomic and cultural factors, which determine the priority in the use of plants. According to Ticktin et al. (2002), a higher socioeconomic importance attributed locally to a plant is a desirable condition to promote management and conservation programs in the communities.

Therefore, in the communities of study it is possible to incorporate the information obtained in this study in the design of strategies for conservation and sustained management of the vegetation, based on the understanding and importance that local people grant the species (Rivera et al., 2007; ^{Del Amo et al., 2010a}). For this purpose, these authors suggest an alternative model of conservation and sustainable development that they have called “biocultural model of resource management”, based on: (1) A reciprocal and integrating dialogue that fosters collective knowledge and citizen participation in planning processes; and (2) The “productive ecological restoration or ethnorestoration” which implies the reduction of anthropogenic disturbances, elimination of exotic species, rehabilitation of soils and waters, remediation of soil pollution, and reintroduction of native species (^{Del Amo et al., 2010b}).

With this study, we have advanced towards the understanding of priority useful species for the inhabitants of the cloud forest of the RBEC, although this does not reflect the totality of their functional potential. However, it will be convenient to corroborate in the field their relevance through concrete measurements, mostly to calculate the natural current offer of the products that can be derived from them, and to implement plans for rational exploitation of the species identified as priority, fact that other researchers have also suggested, such as Pérez-Quilantán et al. (2005) for the RBEC, Martínez-Pérez et al. (2012) for the Mixteca Poblana region and Villavicencio and Pérez-Escandón (2014) for the Huasteca Hidalguense region.