1. Introduction
México is a country with diverse heterogenic landscapes reflecting the presence and anthropogenic history of the contrasting socio-economic development of many cultures within a time span of a few thousand years [
1]. However, natural landscapes in Mexico are currently in threat by rapid antropogenic changes such as deforestation, inadequate land tenure regulation or the intensive agricultural and livestock farming to produce products for human consumption [
2]. However, these landscapes still have the potential to fulfil a broad range of ecosystem services and functions to satisfy the needs of local, national, and global involved stakeholders [
3].
The direct causes of the deforestation rates are interrelated and complex [
4]. In the case of México, increased conflicts over land tenure and foreign and local policies that marginalized the economic position of farmers in the past, are the current causes of deforestation. Many farmers overexploit available natural resources (often due to market pressures) which affect their well-being in the long-term [
5]. With reference to the Mexican rural population, the World Bank concluded that more than 16.9 million peasants (63.6% of the rural population) lived below national rural poverty lines [
6]. Together, indigenous farmers occupy 14.3% of the total land surface in México [
5] and are generally considered as the poorest group of land dwellers [
7].
As described above, México has witnessed increased anthropogenic pressure on the remaining tropical landscapes. Expansion of human activity caused an irreversible, unalterable transformation of its natural ecosystems with cultural consequences caused by a loss of traditional knowledge with respect to usable plant species associated with these ecosystems [
8].
One way to lessen the processes of loss of cultural and biological diversity in rural areas is to develop practical approaches to identify, evaluate, and provide hands-on tools to counteract these processes at a local level. Therefore, recognizing and learning from local management can protect native flora within the systems that are important to well-being. By this way, all types of forest management systems represent a particular degree of management intensity: from the uncontrolled gathering of natural forest products to the intensive management of domesticated tree crops in monoculture plantations [
9]. Between these two extremes, hundreds of site-specific intermediate agroforestry exist [
10]. Eventually, most of the character and appearance of an anthropogenic landscape results in a mosaic of different land use types that occupy a transitional position between monoculture agriculture and natural forests [
11,
12,
13,
14]. This transitional position of agroforestry systems depends on local subsistence strategies aiming to increase the presence of valuable plant species maintained by the local population according to their socio-economic and cultural needs. Nevertheless, this may differ significantly on a local scale [
9].
When the management procedures are not limited to slash and burn methods, most of the plant and animal diversity which remains in these transformed landscapes are relatively well conserved, mostly by indigenous farmers in México [
15]. Their limited economic resources require them to maintain a diverse range of plant species to satisfy basic economic and subsistence needs. Next to these needs, several authors have emphasized the role of agroforestry systems as a strategy for biodiversity conservation [
9,
14,
16]. Hence, agroforestry systems have been recognized for their high potential to reconcile productive purposes with the conservation of biodiversity and ecosystem services [
11].
Common property regimes may contribute to environmental conservation and offer a model that can limit land use and enable natural and cultural capital conservation of these regions [
17]. The ejidos in Mexico, (collective landholdings) which are defined as an extended system of common land parcels collectively managed by peasants, can strengthen land tenure security and improve the efficiency of rural and credit markets [
18]. Currently, 51% of the territory of México is under this form of land ownership. The area of each ejido varies, but the national average is 2156 ha with a surface area of 9.5 ha by owner [
19,
20]. Specifically, in the state of Veracruz, 40% of its territory is under the regime of common land, but with smaller areas called ejido (about 600 ha each). Usually, the ejido are inhabited by people with a high cultural association with their environment, with the majority of
mestizo people dedicated to small-scale land use practices.
In this study, we focused on the description of the agroforestry systems within a representative ejido of the southern state of central Veracruz México named “Los Ídolos”. We focused on the characterization of the link between woody flora and their contribution to subsistence and the cultural identity of local farmers. Therefore, the main goals of our study were: (i) to classify and map the agroforestry systems in “Los Ídolos”; (ii) to identify, using both the scientific literature and local knowledge, the role of woody plant species (exotic and native) and the contribution to the subsistence and cultural needs of farmers found in the local agroforestry systems; and (iii) to identify a set of provisional cultural ecosystem services, qualifying the previous classified agroforestry systems.
4. Discussion
The smallest proportion in the ejido was FG with five ha and covered 2% of the study area. However, the transect data showed that FG had the highest floristic diversity of all the studied systems and formed a habitat for at least 40 different species, which coincides with the findings of Lascurain et al. [
36] and López-Acosta et al. [
37]. These authors identified (municipalities of Misantla, Tenochtitlan, Yecuatla, Mexico) 52 species in ten transects covering 1000 m² in the same region. Interview data indicated that this agroforestry system was the least recognized as potentially useful by the interviewed farmers. The cultural identity, commercial, and subsistence value received 6.8, 3.5, and 5.8, respectively, giving a mean value of 5.4, which might also explain its relatively low area coverage. This low perceived importance of the FG was confirmed by the low use intensity corresponding to a total SUV of 3.9%. Regarding native plant use and protection, the system was very important as all species found and used are native.
HG systems are situated around the homesteads of farmers and at 11 ha, this system accounted for 4.7% of the study area. HG systems had the second highest diversity with 32 identified ligneous plant species, and was also important for the cultural identity of farmers and scored an average of 8.3. Regarding the small size of the HG and a high number of species, the system is important for its subsistence value (8.1), but less so with respect to its commercial value (4.0). The SUV of the HG was 19%, with 58 species mainly used for food, medicinal products, and ornamental services. The number of used species in HG was nearly the same as those measured in area with similar climate conditions corresponding to La Sierra de Misantla: Alvarez-Buylla et al. [
38] identified 62 species in HG systems of Balzapote, Los Tuxtlas, Veracruz. In addition, Van der Wal and Bongers [
39] observed 195 species that might be explained due to a larger sample size (61 home gardens of several sizes) in the state of Tabasco, México with similar species, despite a slightly warmer climate.
AC systems comprised an area of 16 ha (6.8%) with 13 species, the lowest floristic diversity in “Los Idolos”. The woody plant species were less abundant when compared to the other agroforestry systems, which was confirmed by a low measured SUV: none of the interviewed farmers visited the AC for the systematical collection of woody plant products. Even though farmers indicated little interest in cultivating and using trees species in the AC, the agroforestry system scored a high cultural identity value (8.8) and subsistence value (8.6) as these agroforestry systems also provide crops that are eaten daily by both livestock and the inhabitants of the community.
With regard to economic value, the AC scored a 4.4 as staple crops have a low market value. The difference in the extent of extracted exotic and native woody plants could not be measured as the farmers did not use the system for woody plant products. Records from the transect data showed that a third (75%) of the plants were native and 25% were exotic.
PC systems had a size of 49 ha, representing 20.6% of the ejido corresponding to different local examples such as cachichinales, coffee, and citrus plantations. Although they had a relatively large land coverage, they had a lower floristic diversity (18 species) than HG and FG; however, it was relatively similar to that observed by López-Acosta et al. [
37] who identified 28 species in coffee plantations and 26 in the cachichinales. The low diversity was explained by the fact that most PC systems were dominated by introduced perennial commercial trees-shrubs such as
C. arabica,
Citrus aurantifolia,
C. sinensis, and native ones like
O. mexicanum. Different local examples of PC systems (cachichinales, coffee, and citrus plantations) generally scored a high cultural identity value of 7.7 on average. Despite these plantations being partly commercially oriented, the perceived commercial value of 6.5 was rather low as a result of the low market prices for coffee and citrus [
40]. However, the mean subsistence value was 6.9, which was not that high since harvests of collected goods were sold and self-consumption. Taking the mean of the tree measured values, the PCCPC systems scored on average 7.0 for their provided cultural, commercial, and subsistence values. Furthermore, the SUV value of the PCCPC systems accounted for 38% of the 30 used woody plants, which underlined the importance of these systems for securing local subsistence needs. This outcome suggests that more local species were perceived to be useful than that indicated by López-Acosta et al. [
37], who identified 19 useful species in the PCCPC systems (coffee plantations and cachichinales).
TP was the most widespread of all identified agroforestry system in the ejido “Los Ídolos”. This system covered 143 ha and represented 60% of the total surface. The TP had the lowest tree density of all systems and only 20 species with 34 individuals were identified. The cultural and commercial value of TP systems was high with values of 7.9 and 7.8, respectively. The subsistence value was 4.9, lower than the other systems, which may be explained by the low tree density in pasture fields. TP systems were simultaneously promoted by farmers for the extraction of tree products. In contrast, with an SUV value of 39%, several tree products from 46 species were used within the TP systems. This makes the TP species the second most utilized after HG. Additionally, as PCCPC systems, TP had relatively high support to be promoted as a key land use system within the ejido, since several farmers had indicated that they would plant 14 different woody species on TP systems where tree cover is scarce. However, despite low tree densities, the importance values of trees measured in this system were dominated by ul native species (85% of the IVIr).
Due to their multi-functionality, 11 species were determined as the most useful by the interviewed farmers with an RI ranging between 0.73 and 1.03. Six of these 11 species were highlighted for promotion as a key species for reforestation in TP systems with scarce tree cover:
P. schiedeana, which is important for auto consumption and as construction material [
41], and
C. sinensis due to its function as an edible product, firewood, and medicinal use.
O. mexicanum is locally abundant; however worldwide, it is a threatened species which serves—besides its relative high commercial value [
36]—as an important product for auto consumption, construction material, and firewood. Another tree species which can bridge financial gaps in rural families is
C. odorata, a precious timber species [
42], whose wood is also locally used for artisanal furniture, construction material, and medicinal purposes.
P. sapota produces fruits (mamey), medicinal seeds and leaves; and solid timber for local constructions [
35]. The branches of
S. humboldtania can be pruned and are thus well suited as firewood and construction material, while the leaves have medicinal uses. These six-key species, together with 16 other species, can be used to design suitable PC and TP systems.
PC and TP systems are preferred by the farmers to be promoted within the ejido “Los Ídolos” to secure subsistence needs. However, it is necessary to encourage products with commercial potential to maintain the cultural identity of the ejidatarios and conserve biodiversity and genetic diversity in La Sierra de Misantla [
28,
33,
43].
5. Conclusions
This study revealed that the diversity in an agroforestry system corresponded well with the diversity of needed goods for specific cultural, ecological, economic, and subsistence purposes.
To achieve a better land use planning, the landowners in “Los Ídolos” should has a potential trade-off: (i) the farmers choose agroforestry systems such as the IF, HG and CPC to fulfil subsistence security or (ii) they prefer a more economic-oriented destination of the land by choosing a TP system, which generates more financial outcomes through selling timber and allows for keeping livestock, despite the lower abundance of useful woody plants. This depends on the primary needs of each owner and aligned with the collective needs of the ejido.
Pasture lands for cattle ranching are evidently the most popular among the interviewed farmers and cover the largest area due to a growing market for cattle-derived products such as meat [
21]. Still, this study clearly indicated that the maintenance of high (native) species diversity (managed in diverse agroforestry systems) served as an important safety net. This is especially so when the production of (exotic) cash crops suffer low market prices or are influenced by political choices where the importance of locally sustaining traditionally managed agroforestry systems should be underlined [
44].