Influence of traditional markets on plant management in the Tehuacán Valley

Abstract

Background: The Tehuacán Valley, Mexico is a region with exceptionally high biocultural richness. Traditional knowledge in this region comprises information on nearly 1,600 plant species used by local peoples to satisfy their subsistence needs. Plant resources with higher cultural value are interchanged in traditional markets. We inventoried the edible plant species interchanged in regional markets documenting economic, cultural and ecological data and about their extraction and management in order to: (1) assess how commercialization and ecological aspects influence plant management, (2) identify which species are more vulnerable, and (3) analyze how local management contributes to decrease their risk. We hypothesized that scarcer plant species with higher economic value would be under higher pressure motivating more management actions than on more abundant plants with lower economic value. However, construction of management techniques is also influenced by the time-span the management responses have taken as well as biological and ecological aspects of the plant species that limit the implementation of management practices. Plant management mitigates risk, but its absence on plant species under high risk may favor local extinction.

Methods: Six traditional markets were studied through 332 semi-structured interviews to local vendors about barter, commercialization, and management types of local edible plant species. We retrieved ethnobotanical information on plant management from ten communities in a workshop and sampled regional vegetation in a total of 98 sites to estimate distribution and abundance of plant species commercialized. Through Canonical Correspondence Analysis (CCA) we analyzed the amount of variation of management types that can be explained from socioeconomic and ecological information. A risk index was calculated relating distribution, abundance, economic value and management of plant resources to identify the most vulnerable species.

Results: We recorded 122 edible plant species interchanged in the main regional markets. CCA explained significantly 24% of management variation, spatial distribution and plant parts used being particularly important in management decisions. The indeterminate 76% of variation suggests that management decisions depend on particular variables that are not explained by the ecological and socioeconomic factors studied and/or their high variation in the context at the regional scale. The risk index indicated that management was the factor that mostly influences decreasing of risk of interchanged plant species. We identified Clinopodium mexicanum, Pachycereus weberi, Dasylirion serratifolium, Disocorea sp., Ceiba aesculifolia, Neobuxbamia tetetzo, Lippia graveolens, Litsea glaucescens, L. neesiana, Jatropha neopauciflora, Agave potatorum and other agave species used for producing mescal among the more endangered plant species due to human pressure, their relative scarcity and limited or inexistent management.

Conclusion: Spatial distribution and plant parts used are particularly meaningful factors determining risk and influencing management actions on edible plant species interchanged in the region. Limited or inexistent management may favor extinction of local populations under risk. Local management techniques synthesize knowledge and experiences crucial for designing sustainable management programs. Traditional management techniques supported by ecological information and environmental management approaches could make valuable contributions for sustainable use of plant species, particularly those becoming economically important more recently.

Figure 1

Study area. Numbers indicate the location of the traditional markets studied in the Tehuacán-Cuicatlán Valley. Letters indicate some places where sellers come from.

Figure 2

Partition of the variation of a response matrix Y between Ecological (matrix X) and Socioeconomic (matrix W) explanatory variables. Fraction (b) is the intersection of the ecological and socioeconomic components of the management variation. The length of the horizontal line corresponds to 100% of the variation of Y. Modified from Boccard et al. 1992.

Figure 3

Edible species numbers in relation to the part consumed in the Tehuacan-Cuicatlán Valley markets.

Figure 4

Relative contribution of ecological (Eco), socioeconomic (soEco) and management (Mgn) factors on the risk index value (R). In both panels the arrows show the direction of lecture of each factor. For example, in panel B species plant circled 45 (Renealmia alpina) has a risk value 2 (intermediate risk) in panel A. This species has the same coordinates in both panels (Eco = 0.55, SoEc = 0.13, Mgn = 0.35). A. Absolute magnitudes of index risk values. Larger numerical values denote higher risk index values. Each plant species is represented with a number code: 1) low risk (0.32 < R ≤ 0.39); 2) intermediate risk (0.40 < R ≤ 0.49); 3) intermediate-high risk (0.5 < R ≤ 0.59); 4) high risk (0.6 < R ≤ 0.67). B. Species identity in the triangle. Acronyms = 1: Agave potatorum, 2: A.sp.1, 3: A.sp.2, 4: Amaranthus hybridus, 5: Apodanthera aspera, 6: Byrsonima crassifolia, 7: Capsicum annuum, 8: C. annuum var. annuum, 9: C. annuum var. aviculare, 10: Ceiba aesculifolia subsp. parvifolia, 11: Chamaedorea tepejilote, 12: Chenopodium ambrosioides, 13: C. berlandieri, 14: Crataegus pubescens, 15: Crotalaria pumila, 16: Cucurbita mostacha, 17: C. pepo, 18: Cyrtocarpa procera, 19: Dasylirion serratifolium, 20: Dioscorea sp., 21: Escontria chiotilla, 22: Ferocactus latispinus, 23: Inga jinicuil, 24: Jatropha neopauciflora, 25: Leucaena esculenta, 26: L. leucocephala, 27: Lippia graveolens, 28: Litsea glaucescens, 29: L. neesiana, 30: Myrtillocactus geometrizans, 31: Neobuxbaumia tetetzo, 32: Pachycereus weberi, 33: Peperomia peltilimba, 34: Persea americana, 35: Phaseolus coccineus, 36: P. sp., 37: P. vulgaris, 38: Physalis philadelphica, 39: Phytolacca icosandra, 40: Pinus cembroides, 41: Pithecellobium dulce, 42: Porophyllum linaria, 43: P. macrocephalum, 44: Prunus serotina, 45: Renealmia alpinia, 46: Clinopodium mexicanum, 47: Sechium edule, 48: Sideroxylon palmeri, 49: Solanaceae sp., 50: Solanum lycopersicum, 51: S. nigrescens, 52: S. sp., 53: Spathiphyllum cochlearispathum, 54: Spondias mombin, 55: S. purpurea, 56: Stenocereus pruinosus, 57: S. stellatus, 58: Witheringia solanacea, 59: Yucca periculosa.

Figure 5

Trade routes of edible plants species at Tehuacán-Cuicatlán Valley. Edible plant species came from the forest, agroforestry system (AFS) and from home gardens and are produced at low scale. Gray area corresponds to the analysis of this study. 1 = interchange between village inhabitants through barter or commercialization, 2 = plants taken to the market by village inhabitants and exchanged for money or other products, 3 = Plants exchanged for money or other products by middlemen inside villages, 4 = Plants collected at villages and offered directly by middlemen or wholesalers who exchange only for money at the market.