Use of columnar cacti in the Tehuacan Valley, Mexico: perspectives for sustainable management of non-timber forest products

Background: TEK, ecological and economic aspects of columnar cacti were studied in the Tehuacan Valley, Mexico to design sustainable regimes of fruit harvest. We analysed the amounts of edible fruit, seeds and flowers produced per hectare of cardonal, jiotillal and tetechera forests, their economic value and actual extraction rates, hypothesizing that the economic benefits of these NTFP would potentially be comparable to maize agriculture, which involves forest removal. Methods: Our study comprised the whole territory of the community of Quiotepec, Oaxaca. Sustainable gathering rates were analysed through population dynamics models and simulations of harvesting regimes (10%, 25%, and 50% of fruit gathered) per hectare of forest type. We used estimations on economic benefit and ecological impact of these scenarios to evaluate their relative sustainability, compared with maize agroforestry systems harbouring 2-47% of vegetation cover. Results: For the whole territory, the total annual fruit production is 509.3 ton of Pachycereus weberi, 267.4 ton of Neobuxbaumia tetetzo, 99.5 ton of Escontria chiotilla, and 8.1 ton of Myrtillocactus geometrizans. The total economic value of fruits per hectare was $ 315.00 U.S. dollars for cardonal, $ 244.60 for jiotillal, and $ 113.80 for tetechera, whereas rainfed agriculture of maize was on average $ 945.52. Demographic models for E. chiotilla and N. tetetzo indicate that 70% and 95% of fruit harvesting, respectively maintain lambda > 1, but these harvest rates cannot be recommendable since the models do not consider the high inter-annual environmental variations and the non-estimated amount of fruit consumed by natural frugivorous. Extracting 25% of fruit is ecologically more sustainable, but with low economic benefits. Agroforestry systems maintaining the higher vegetation cover provide economic benefits from agriculture and forest resources. Conclusions: Combining forest extraction and agroforestry systems are ideal scenarios to sustainable fruit harvest programmes. In addition, fair commerce of transformed products would substantially favour goals of sustainable management.