Semiarid Ethnoagroforestry Management: Tajos in the Sierra Gorda, Guanajuato, Mexico Vincent M
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Hoogesteger van Dijk et al. Journal of Ethnobiology and Ethnomedicine (2017) 13:34 DOI 10.1186/s13002-017-0162-y RESEARCH Open Access Semiarid ethnoagroforestry management: Tajos in the Sierra Gorda, Guanajuato, Mexico Vincent M. Hoogesteger van Dijk1, Alejandro Casas1 and Ana Isabel Moreno-Calles2* Abstract Background: The semi-arid environments harbor nearly 40% of biodiversity, and half of indigenous cultures of Mexico. Thousands of communities settled in these areas depend on agriculture and using wild biodiversity for their subsistence. Water, soil, and biodiversity management strategies are therefore crucial for people’s life. The tajos, from Sierra Gorda, are important, poorly studied, biocultural systems established in narrow, arid alluvial valleys. The systems are constructed with stone-walls for capturing sediments, gradually creating fertile soils in terraces suitable for agriculture in places where it would not be possible. We analyzed biocultural, ecological, economic and technological relevance of the artificial oasis-like tajos, hypothesizing their high capacity for maintaining agricultural and wild biodiversity while providing resources to people. Methods: We conducted our research in three sections of the Mezquital-Xichú River, in three communities of Guanajuato, Mexico. Agroforestry management practices were documented through semi-structured and in-depth qualitative interviews. Vegetation composition of local forests and that maintained in tajos was sampled and compared. Results: Tajos harbor high agrobiodiversity, including native varieties of maize and beans, seven secondary crops, 47 native and 25 introduced perennial plant species. Perennial plants cover on average 26.8% of the total surface of plots. Tajos provide nearly 70% of the products required by households’ subsistence and are part of their cultural identity. Conclusions: Tajos are heritage of TEK and land management forms of pre-Columbian Mexican and Mediterranean agricultural techniques, adapting and integrating modern agricultural practices. Tajos are valuable biocultural systems adapted to local semiarid conditions and sources of technology for similar areas of the World. Keywords: Agrobiodiversity, Arid zones, Biocultural heritage, Mesoamerica, TEK Background areas of Mexico depend on agriculture and use of local Steep slopes, severe long dry seasons, low rainfall, scarce wild biodiversity for their subsistence [3]. In such con- plant cover, and shallow soils are common features of text, the construction of water control, irrigation systems landscape dry areas of Mexico, a Country with nearly and strategies for preserving both water and soils such 60% of its territory occurring in arid, semi-arid and sub- as the agroforestry terraces that allow favorable farming humid environments. These areas, however, lodge about conditions, have been historically main worries of peo- 40% of the biodiversity of the country and most endemic ples practicing agriculture in arid lands [4]. Although species [1]. In addition, these areas, harbor high human studies examining peasant agroforestry land manage- cultural richness, being inhabited by 30 of the 58 main ment in semiarid lands of Mexico are scarce, some of indigenous ethnic groups identified in the country [2]. them have documented that these systems involve man- Thousands of communities settled in arid and semi-arid agement of wildlife and agro-biodiversity. In the arid zones of this country, Altieri and Toledo [5], for in- * Correspondence: [email protected] stance, described agroforestry terraces belonging to the 2Escuela Nacional de Estudios Superiores Unidad Morelia, Universidad Nacional Autónoma de México (UNAM), Antigua Carretera a Pátzcuaro 8701, Ñahñú people of the Mezquital Valley, Hidalgo and the Col. San José de la Huerta, 58190 Morelia, Michoacán, Mexico Papago communities in the Sonoran Desert showing a Full list of author information is available at the end of the article © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Hoogesteger van Dijk et al. Journal of Ethnobiology and Ethnomedicine (2017) 13:34 Page 2 of 11 significant amount of biodiversity management involved Methods in the systems. Our research group conducted studies in Study area the Tehuacán Valley, Puebla with different agroforestry Tajos are in the municipality of Xichú, Guanajuato, in systems (AFS) that associate maize production with themountainousregionoftheSierraGorda,whichis columnar cacti, rosetophyllous scrub, chaparral, mes- partoftheSierraMadreOrientalofMexico.Thephy- quite, and palm forests handled by Náhuatl, Popoloca, siography of this region is characterized by pronounced Cuicatec, Mixtec, Ixcatec, and Mestizo peoples of the mountains forming deep canyons, with semi-arid in- Tehuacán Valley [6–9]. Also outstanding are the oases termountain valleys, and small alluvial valleys (locally managed by people in Baja California [10, 11] and the called vegas) on the banks of streams and rivers. There desert gardens in San Luis Potosí [4], and the huamil sys- are some plateaus and small areas of hillocks, which are tem in the region of the Valley of Santiago, Guanajuato inaccessible for obtaining natural resources. The area [12], which associates Opuntia species with maize [13]. still harbors well-conserved natural vegetation that has The common finding of all these studies is that AFS of remained at low impairment [17–19], reason the arid and semiarid zones provide ecosystem benefits such Mexican Government decreed the Biosphere Reserve as refuges for pollinators and seed dispersers, bridges Sierra Gorda in February 2007 [20]. that at landscape and plot level contribute to maintain The study area includes the rural communities of the regional biodiversity, prevent soil erosion, and main- Organitos, Llanetes, and La Laja (Fig. 1). Organitos is in tain water and soil storage. At the same time, AFS con- the upper river area, at an elevation of 1200 m, Llanetes tribute to decrease the risk of losing supply of natural is in the middle part at 930 m and La Laja is in the resources for satisfying livelihoods. In addition, these lower area (<900 m). The communities belong to the systems contribute to form complex and heterogeneous Ejido Las Ajuntas, conformed by scattered hamlets lo- landscapes with high agro-biodiversity, which help to re- cated mainly on slopes above the floodplain (Fig. 2). The duce deforestation for establishing new agricultural community of Organitos is composed only by 30 house- areas, making easier the conservation and restoration holds, while La Laja is inhabited by nearly 100 house- the bio-cultural diversity [14, 15]. holds, according to the local authorities. The tajos, practiced by people of the Sierra Gorda, Climate of the study area is subtropical dry, semi-arid, central Mexico, are highly dynamic and important agro- influenced by the rain shadow caused by the mountains forestry systems that however have been scarcely stud- surrounding the lower parts of the basin, with average ied. These AFS involve irrigation and soil management annual temperatures from 20 °C to 29 °C and annual techniques using the ground, sand and organic materials rainfall varying from 450 to 600 mm [17, 18]. Soils are carried by the river, and are specifically designed by local mostly shallow lithosols, except in the agricultural areas people, according to the surface allowed by the alluvial of alluvial valleys where these are formed by luvisols areas, slope inclination, and other environmental condi- resulting from artificial sediment capture [19, 21]. In the tions. Tajos are constructed in the lower and arid parts study, it is possible to distinguish two environmental of the mountainous region of the northeastern Sierra units: The alluvial valley formed by the passage of the Gorda, in the area considered in the past to be the Mezquital-Xichú River, and the steep slopes and ravines northern boundary of Mesoamerica, just in the frontier surrounding this valley (Fig. 3). with the cultural region called Aridoamerica [16]. Agro- Local people practice the agriculture of tajos where forestry and hydraulic management of the river se- the original vegetation is gallery forest surrounded by diments make possible that tajos become land for steep and barren slopes and ravines dominated by shal- agriculture where natural conditions do not allow it. low soils of limestone and vegetation represented mainly This study analyzes the ecological, economic and cul- by tropical deciduous forest (TDF) and rosetophyllous tural importance of the tajos in the Sierra de Xichú, scrub (RS) [17, 21]. Guanajuato, Mexico. We particularly explored the fol- lowing questions: i) Which are the main wild and do- Documenting agriculture and agroforestry practices in mesticated components of tajos, the diversity and tajos composition of perennial plant species, ii) what is the For selecting the study plots we considered that: i) the role of tajos in maintaining the household economy of plots