Ignacio Torres

Plant Management in the Tehuacán-Cuicatlán Valley, Mexico1

Plant Management in the Tehuacán-Cuicatlán Valley, Mexico. Plant management types currently practiced in the Tehuacán-Cuicatlán Valley, México, were documented and analyzed based on ethnobotanical studies conducted in 13 villages with six indigenous groups and Mestizo people. The information was organized in a data base, and then detailed and guided to a consensus through six workshops carried out by ethnobotanists working in the area. From a total of 1,608 useful plant species, we identified 610 with at least one management type other than simple gathering. Managed species are mainly used as food, fodder, medicinal, and ornamental, and they belong to 101 plant families. The higher species numbers were recorded in Cactaceae, Asteraceae, Fabaceae, Crassulaceae, and Agavaceae. Nearly 60% of the managed species are native to the region and the rest are introduced from other regions of Mexico and the world. In total, 400 species are ex situ managed out of their natural environments through seed sowing and/or planting their vegetative propagules or entire young plants; 373 species are in situ managed in their natural habitats as follows: all these species are deliberately left standing during vegetation clearance, 76 species are also enhanced intentionally favoring their abundance through modifications of their habitat, or directly by planting their propagules, and 51 receive protection through regulations, particular strategies of extraction, and actions against herbivores, competitors, freezing, radiation, and drought. Most management forms involve artificial selection at different intensity levels. The information allows visualizing co-occurrence of incipient and advanced forms of management at different intensity levels within and among species, which helps to postulate testable hypotheses on factors influencing plant management and domestication in an important area for studying the origins of agriculture.Manejo de plantas en el Valle de Tehuacán-Cuicatlán, México. Se documentaron los diferentes tipos de manejo de plantas que practican actualmente los pobladores del Valle de Tehuacán-Cuicatlán, México. El análisis se basa en estudios etnobotánicos llevados a cabo en 13 comunidades campesinas con seis grupos indígenas y poblados mestizos. La información se organizó en una base de datos, la cual posteriormente se detalló y se consensó a través de seis talleres en los que participaron los etnobotánicos trabajando en la región y cuyos trabajos son la base de esta investigación. De un total de 1,608 especies de plantas útiles, identificamos 610 con al menos un tipo de manejo distinto a la recolección simple. Las especies manejadas pertenecen a 101 familias botánicas y se utilizan principalmente como alimento, forraje, medicina y ornamentales. Los mayores números de especies manejadas se registraron entre las Cactaceae, Asteraceae, Fabaceae, Crassulaceae y Agavaceae. Aproximadamente 60% de las especies manejadas son nativas de la región y el resto son introducidas de otras regiones de México y del mundo. En total, 400 especies se manejan ex situ, fuera de sus ambientes naturales, mediante la siembra de sus semillas y la plantación de sus propágulos vegetativos o plantas juveniles; 373 especies se manejan in situ en sus hábitats naturales como sigue: todas estas especies se dejan en pie deliberadamente durante el aclareo de la vegetación; 76 especies son además promovidas intencionalmente, favoreciendo sus abundancias mediante modificaciones a sus hábitats o directamente plantando sus propágulos; y 51 especies reciben protección a través de reglas comunitarias, estrategias particulares de extracción y acciones contra herbívoros, competidores, heladas, radiación solar y sequías. La mayor parte de las formas de manejo involucran selección artificial a diferentes niveles de intensidad. La información permite visualizar la ocurrencia de formas de manejo incipientes y avanzadas a diferentes niveles de intensidad, simultáneamente dentro de una misma especie y entre especies. Esto permite postular hipótesis probables sobre los factores que influyen el manejo de plantas y su domesticación en una región importante para el estudio sobre el origen de la agricultura.

Traditional Knowledge and Useful Plant Richness in the Tehuacán-Cuicatlán Valley, Mexico

Traditional Knowledge and Useful Plant Richness in the Tehuacán–Cuicatlán Valley, Mexico. This study systematizes ethnobotanical information about the interactions between people and plants, ethnofloristic richness, the relative importance of useful species richness in relation to general species richness, and plant management in the Tehuacán–Cuicatlán Valley of central Mexico. The study recorded a total of 1,605 useful vascular plant species (61.2% of the total species richness of the regional vascular flora), this being the region with the highest absolute richness of useful plant species in Mexico. The null hypothesis that plant families with a higher number of useful species would be those having a higher general species richness was analyzed through residuals method. The plant families richest in useful species were Poaceae, Asteraceae, Cactaceae, Cyperaceae, Mimosaceae, and Solanaceae, most of which also have the highest general floristic richness. However, analyses of use categories did not generally corroborate our hypothesis. About 1,335 of the useful species are wild, more than 500 species are submitted to some type of management (62 species are tolerated, 34 protected, 50 enhanced, and 358 cultivated), but only a few have been studied to document their process of domestication. This information can be useful for developing regional strategies of sustainable management of plant resources.Conocimiento tradicional y riqueza de plantas útiles en el Valle de Tehuacán-Cuicatlán, MéxicoConocimiento tradicional y riqueza de plantas útiles en el Valle de Tehuacán-Cuicatlán, México. Este trabajo sistematiza información etnobotánica sobre las interacciones entre la gente y las plantas, la riqueza etnoflorística, la importancia relativa de las especies útiles con respecto a la riqueza florística general, y sobre el manejo de plantas en el Valle de Tehuacán–Cuicatlán, en el centro de México. Se registró un total de 1,605 especies de plantas vasculares útiles (61.2% de la riqueza total de la flora vascular de la región), lo que identifica a la región como la de mayor riqueza de plantas útiles de México en términos absolutos. Mediante el método de residuales se analizó la hipótesis nula de que las familias con mayor número de especies útiles serían las de mayor riqueza florística. Se encontró que las familias con mayor número de especies útiles fueron Poaceae, Asteraceae, Cactaceae, Cyperaceae, Mimosaceae, y Solanaceae, las cuales en su mayoría son las de mayor riqueza florística en la región. No obstante, al efectuar el análisis por categorías de uso no siempre se confirmó nuestra hipótesis. Casi 1,335 de las plantas útiles son silvestres, pero alrededor de 500 están sometidas a algún tipo de manejo (62 especies son toleradas, 34 protegidas, 50 fomentadas y 358 cultivadas), pero sólo para algunas de ellas se ha estudiado cómo operan los proceso de domesticación. La información generada en el trabajo puede ser útil para el desarrollo de estrategias regionales de manejo sustentable de los recursos vegetales.

Agroforestry systems and biodiversity conservation in arid zones: the case of the Tehuacan Valley, Central Mexico

The role of agroforestry systems in biodiversity conservation was investigated in the semiarid Tehuacán Valley, Central México. Richness and diversity of native plant species were compared between agroforestry systems (6 sampling sites) and the following forests (6 sampling sites) dominated by columnar cacti: (i) “chichipera” dominated by Polaskia chichipe; (ii) “jiotillal” dominated by Escontria chiotilla; and (iii) “garambullal” dominated by Myrtillocactus schenckii. Our information on genetic variation of dominant arboreal species in the study sites was reviewed and included in the analysis. Factors influencing household’s decisions to maintain vegetation cover were compiled through a survey and interviews and analyzed. All the samples of the agroforestry systems studied maintained on average nearly 59% plant species and 94% genetic variation of dominant cacti occurring in the forests, although their ability to preserve endemic rare species is limited. Social factors favoring maintenance of perennial species in agricultural plots include collective rules, households traditions, use of the plants maintained in the systems, and the environmental information gathered from NGOs, the local Biosphere Reserve, and researchers. However, agroforestry systems are losing their capability to maintain vegetation cover, mainly because of (i) decreasing amount of land managed by households, determined by a progressive fragmentation of the land area given to new families, (ii) adoption of technologies to intensify agriculture, and (iii) governmental programs penalizing the presence of vegetation patches within agricultural lands since they are considered “useless” areas. Necessary policies to stop degradation of the agroforestry systems and to improve their conservation capacity are discussed.

Vulnerability and risk management of Agave species in the Tehuacán Valley, México

BackgroundOur study analysed the vulnerability of the useful Agave species of the Tehuacán Valley, Mexico, considering ecological, cultural and economic aspects, and management types. We hypothesized that management intensity is proportional to the degree of risk of a species in order to decrease its vulnerability.MethodsDistribution of Agave species was monitored in 36 types of plant associations. Ethnobotanical studies were conducted in 13 villages and six markets. The vulnerability of each species was calculated by assigning risk values to the variables analysed. The vulnerability and management intensity indexes were estimated through the scores of the first principal component of PCA. Variation of management data explained by ecological, cultural and economic information were analysed through canonical correspondence analyses (CCA). A linear regression analysis identified the relation between vulnerability and management intensity.ResultsWe recorded presence of agave species in 20 of 36 vegetation types. Out of 34 Agave species, 28 were recorded to have one to 16 use types; 16 species are used as food, 13 for live fences, 13 for producing ‘pulque’, 11 for fibre and ornamental, 9 for construction. Seven species are used for preparing mescal, activity representing the highest risk. Seven Agave species are exclusively extracted from the wild and the others receive some management type. Incipient cultivation was identified in A. potatorum whose seedlings are grown in nurseries. Intensive cultivation through vegetative propagation occurs with domesticated species of wide distribution in Mexico. The highest management intensity values were recorded in widely distributed, cultivated and domesticated species, but the regionally native species more intensively managed were those with higher demand and economic value, protected by collective regulations because of their scarcity. The regression analysis indicated significant relation (R2=0.677, P<0.001) between vulnerability and management indexes. CCA explained 61.0% of variation of management intensity, mainly by socio-cultural factors (30.32%), whereas ecological data explained 7.6% and the intersection of all factors 21.36%.ConclusionsThe highest vulnerability was identified in wild species restrictedly distributed and/or highly extracted. Social pressures may increase the natural vulnerability of some species and these species are particularly those native species receiving some management form.

Influence of traditional markets on plant management in the Tehuacan Valley.

BackgroundThe 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.MethodsSix 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.ResultsWe 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.ConclusionSpatial 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.

Chimeric Infectious Bursal Disease Virus-Like Particles as Potent Vaccines for Eradication of Established HPV-16 E7-Dependent Tumors

Cervical cancer is caused by persistent high-risk human papillomavirus (HR-HPV) infection and represents the second most frequent gynecological malignancy in the world. The HPV-16 type accounts for up to 55% of all cervical cancers. The HPV-16 oncoproteins E6 and E7 are necessary for induction and maintenance of malignant transformation and represent tumor-specific antigens for targeted cytotoxic T lymphocyte–mediated immunotherapy. Therapeutic cancer vaccines have become a challenging area of oncology research in recent decades. Among current cancer immunotherapy strategies, virus-like particle (VLP)–based vaccines have emerged as a potent and safe approach. We generated a vaccine (VLP-E7) incorporating a long C-terminal fragment of HPV-16 E7 protein into the infectious bursal disease virus VLP and tested its therapeutic potential in HLA-A2 humanized transgenic mice grafted with TC1/A2 tumor cells. We performed a series of tumor challenge experiments demonstrating a strong immune response against already-formed tumors (complete eradication). Remarkably, therapeutic efficacy was obtained with a single dose without adjuvant and against two injections of tumor cells, indicating a potent and long-lasting immune response.

Population Dynamics and Sustainable Management of Mescal Agaves in Central Mexico: Agave potatorum in the Tehuacán-Cuicatlán Valley

Population Dynamics and Sustainable Management of Mescal Agaves in Central Mexico:Agave potatorumin the Tehuacán-Cuicatlán Valley. A total of 37 agave species are extracted from forests of Mexico for producing mescal. This activity has caused decline of numerous populations, and their sustainable management is indispensable for preventing species extinctions. Our study analyzed demographic information about Agave potatorum in the Tehuacán Valley with the goal of developing proposals for sustainable use for agaves in general. We studied protected populations in two contrasting environments, and through prospective analyses and real data about extraction and reforestation rates, we simulated different scenarios of actions. Our analyses indicate that the populations’ growth rates (λ) in conserved populations are 0.9903 ± 0.062 and 1.021 ± 0.062, but viability analyses suggest that even those unmanaged populations would decrease 30% to 90% in 30 years. Survival and growth of early agave plant stages contribute most to λ; adult stages and fecundity have low contribution but their conservation is crucial for population recovery. Based on a successful management experience with A. cupreata, we suggest that at least 30% of reproductive plants should be left to ensure seed provision for natural and assisted populations’ recovery. The reintroduction of plants at two early stages of growth is recommended, particularly 1–2-year-old plants, the size categories with the highest contribution to λ. Current efforts by local people to promote cattle exclusion from forest areas, seed collection, and their propagation in nurseries, and actions for recovery and conservation of populations are strategies of high value. Our research contributes to optimizing the effectiveness of such actions and aids in the conservation of other agave species.Dinámica de poblaciones y manejo sustentable de agaves mezcaleros en la región central de México:Agave potatorumen el Valle de Tehuacán-Cuicatlán. En total, 37 especies de agaves se extraen de los bosques de México para producir mezcal, lo que ha determinado la degradación o extinción de numerosas poblaciones. Su manejo sustentable es indispensable para evitar la extinción de poblaciones y aún especies. Nuestro estudio analizó información demográfica de poblaciones de Agave potatorum del Valle de Tehuacán con el fin de desarrollar propuestas generales para el uso sustentable de agaves. Estudiamos poblaciones conservadas de agave en dos ambientes contrastantes y a través de análisis prospectivos e información real sobre tasas de extracción y reforestación simulamos las consecuencias de diferentes escenarios de acciones para la conservación. Nuestros análisis indican que las tasas de crecimiento (λ) en poblaciones conservadas son 0.9903 ± 0.062 y 1.021 ± 0.062, respectivamente, pero los análisis de viabilidad poblacional sugieren que aún tales poblaciones decrecerían de 30 a 90%, respectivamente en 30 años. La sobrevivencia y crecimiento de las etapas tempranas del ciclo de vida contribuyen mayormente al valor de λ. Las etapas adultas y la fecundidad tienen baja contribución, pero el manejo sustentable y el manejo de restauración sustentable de las poblaciones requieren que éstas se mantengan. Con base en una experiencia exitosa de manejo de A. cupreata sugerimos que al menos 30% de las plantas reproductivas sean respetadas para asegurar provisión de semillas para la recuperación natural y asistida de las poblaciones. La reintroducción de plantas de1 a 2 años de edad es necesaria, particularmente porque éstas son las categorías de tamaño con mayor contribución a λ. Los esfuerzos actuales que lleva a cabo la gente de la zona para promover la exclusión del ganado a las áreas forestales, la recolecta de semillas, su propagación en viveros, así como las acciones para la recuperación y conservación de poblaciones constituyen estrategias de alto valor. Nuestra investigación busca contribuir a optimizar la efectividad de tales acciones y ayudar a las que se pueden llevar a cabo con otras especies de agave que se extraen de los bosques.

Evolutionary Ethnobotanical Studies of Incipient Domestication of Plants in Mesoamerica

Human cultures that occupied the area currently known as Mesoamerica developed a broad repertory of technologies for managing the biotic resources and ecosystems of the surrounding areas they lived. These technologies emerged from early experiences and had long time, enough for leading to the first forms of agriculture of the New World. Mesoamerica is actually recognized as one of the regions where agriculture and domestication of plants originated, with nearly 10,000 years of antiquity. This chapter summarizes ethnobotanical, ecological, and evolutionary information documented in different regions of Mexico, combining different research approaches in order to understand the human motives for managing plant resources, and the ecological and evolutionary consequences of management of plants and ecosystems. We therefore analyse those processes involving domestication as part of general design of nature according to human needs and desires, occurring at the levels of plant population of particular species, but also at the level of ecosystems and landscapes. We pay particular attention in the analysis of plant species that in the Mesoamerican area have wild and domesticated populations and maintain reproductive interactions. These interactions allow exploring practices and natural processes intervening in conforming populations in which divergence populations guided by natural and artificial selection and other evolutionary forces are occurring. Because natural processes continually weaken the human activities, the divergence is relatively slight and we have therefore called these processes incipient domestication. We analyse the cases of traditional greens called ‘quelites’ such as Anoda cristata and Crotalaria pumila in which people distinguish favourable and unfavourable morphs and practice artificial selection resulting in the abundance of the favourable morphs in areas more intensively managed. Similarly, some examples are analysed of trees (Leucaena esculenta, Crescentia spp. Spondias purpurea, S. mombin, and Sideroxylon palmeri), agaves (Agave inaequidens and A. hookeri), and columnar cacti (Escontria chiotilla, Myrtillocactus schenckii, Pachycereus hollianus, Polaskia spp., Stenocereus spp.). In the cases studied we analysed divergence in morphology, reproduction, population genetics, and germination patterns, among other features, between wild, silvicultural managed and cultivated populations. These case studies allow demonstrating that evolutionary divergence influenced by humans occurs not only under agriculture but also under silvicultural management and we hypothesize that domestication under silvicultural systems could have leaded to the origins of agriculture.

The Metagenome of Utricularia gibba's Traps: Into the Microbial Input to a Carnivorous Plant

The genome and transcriptome sequences of the aquatic, rootless, and carnivorous plant Utricularia gibba L. (Lentibulariaceae), were recently determined. Traps are necessary for U. gibba because they help the plant to survive in nutrient-deprived environments. The U. gibbas traps (Ugt) are specialized structures that have been proposed to selectively filter microbial inhabitants. To determine whether the traps indeed have a microbiome that differs, in composition or abundance, from the microbiome in the surrounding environment, we used whole-genome shotgun (WGS) metagenomics to describe both the taxonomic and functional diversity of the Ugt microbiome. We collected U. gibba plants from their natural habitat and directly sequenced the metagenome of the Ugt microbiome and its surrounding water. The total predicted number of species in the Ugt was more than 1,100. Using pan-genome fragment recruitment analysis, we were able to identify to the species level of some key Ugt players, such as Pseudomonas monteilii. Functional analysis of the Ugt metagenome suggests that the trap microbiome plays an important role in nutrient scavenging and assimilation while complementing the hydrolytic functions of the plant.

Ethnobotany for Sustainable Ecosystem Management: A Regional Perspective in the Tehuacán Valley

Different indicators of global change identify that industrial processes are principal causes of the severe human impact on ecosystems of Earth. However, although industrial processes predominate in the world, numerous rural societies with a different rationality and organization coexist with the hegemonic mode of production. In indigenous communities the traditional botanical, zoological and ecological knowledge as well as traditional technologies of local resources and ecosystem management are particularly rich, as product of hundreds or thousands of years of experience. Indigenous communities have historically built diverse forms of managing the socioecological systems and the biocultural diversity adapted to local conditions, which are generally much more environmental friendly than other intensive forms of management. In this study we document the management of plant resources by peoples of the Tehuacan Valley, Mexico. We have inventoried more than 1600 plant species used for satisfying a broad spectrum of needs. People gather nearly 90 % of those species from wild populations, but practice different forms of incipient management (tolerance, enhancing, transplantation and seed sowing) in order to increase availability of nearly 400 important plant resources. The indigenous communities may adopt some modern techniques of managing resources and ecosystems, and select those according with their conditions and views. Based on these processes people construct hybrid techniques that may be adapted to the local environments. Agroecologists and ethnobotanists have visualized the high value of traditional management systems for generating technological viable alternatives for designing forms of sustainable management adapted to satisfy local needs and conserving biodiversity and ecosystems, and the continuous innovation tested by local people. It has been recognized that, in general, the traditional management systems have higher capacity for conserving biodiversity and ensuring the resilience of socioecological systems than industrial systems and that both traditional and modern techniques may contribute to better forms of management, but the form that the process adopts is crucial. Understanding traditional management systems are therefore the opportunity to reproduce valuable experiences, models and lessons for sustainable management and participatory adoption of new techniques may help to solve problems not traditionally solved. This chapter shows a general panorama of ethnobotanical information about resources and local traditional management strategies among Nahua, Mixtec, Mazatec, Cuicatec, Popoloca, Ixcatec and Mestizo peoples of the Tehuacan Valley, in order to analyse their role in designing a future for the region based on sustainability, an experience that may be useful for this and other regions of Mexico.