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Abstract:Prosopis laevigata and Mimosa biuncifera are frequently found in arid and semiarid shrublands, but scarce information is available about their influence on plant community structure and soil fertility. We compared plant community structure, diversity and soil nutrients of three semiarid shrubland sites located in Mezquital Valley, Mexico. These sites differ in their dominant species: Site 1 (Bingu) P. laevigata, Site 2 (González) M. biuncifera, and Site 3 (Rincón) with the presence of both legumes. The results showed that the plant community with P. laevigata and M. biuncifera (Site 3) had more cover, taller plants and higher plant diversity than sites with only one legume (Site 1 and Site 2). Soil organic matter (SOM), soil organic carbon (SOC), total nitrogen (TN), phosphorus-Olsen (P) and C mineralization were higher in the soil under the canopy of both legumes than in bare soil. In contrast, soil cation concentrations were lower under the canopy of P. laevigata, but not for M. biuncifera. In addition, the density of arbuscular mycorrhizal fungi spores was higher within the soil under the canopy of M. biuncifera than in the soil under the canopy of P. laevigata. Thus, resource islands (RI) created by P. laevigata increased the amounts of SOC, TN and P when compared with the RI of M. biuncifera. This study provided evidences about the importance of species identity in order to expand the niche availability for the establishment of other plants, and highlights that P. laevigata and M. biuncifera jointly influencing plant colonization within semiarid ecosystems. Rev. Biol. Trop. 60 (1): 87-103. Epub 2012 March 01.

The recovery in richness, composition, structure and tree diversity was studied in three conditions of secondary tropical deciduous forest with different time of abandonment (C35, C45 and C65 years) in the southeast of the state of Morelos. In each condition, three plots of 50 × 50 m (2,500 m 2) were established and all individuals ≥ 2.5 cm of normal diameter (ND) were measured. In total, 2,791 individuals belonging to 79 species, 53 genera and 30 families were registered. Fabaceae was the family with the largest number of species and individuals. C45 had the highest species richness (57), followed by C35 (48) and C65 (43). The conditions were different (p < 0.0001) in basal area, total height, ND and crown coverage. The species with the highest relative value of importance (IVIR) and forest value (IVFR) were

<p>Hintonia latiflora (Sessé &amp; Moc. ex DC.) Bullock, la “quina amarilla”, es un árbol americano propio del bosque tropical caducifolio, valioso, debido a que la corteza tiene propiedades medicinales. La principal zona de abasto comercial de quina amarilla está al norte del estado de Guerrero, México. Esta contribución aporta información bibliográfica en torno a la historia natural y del aprovechamiento de <em>H. latiflora</em> en toda su área de distribución. Además, incorpora datos de campo originales acerca del hábitat, densidad, fenología, dispersión, arquitectura, comercialización e intensidad en el aprovechamiento de algunas poblaciones de quina amarilla de la cuenca alta del Río Balsas. Se encontraron factores biofísicos importantes para el establecimiento, crecimiento y supervivencia de la especie. La fenología consiste en la floración en la primavera-verano, foliación en el verano, fructificación a finales del verano y dispersión durante el invierno. La dispersión es anemócora y barócora. La arquitectura arbórea se relaciona con factores ambientales y la cosecha de corteza. Se observó que la densidad y disponibilidad de la especie cambian con las características de los sitios y con la intensidad de recolección. La comercialización de la quina implica a tres actores: los recolectores, los acopiadores locales y los compradores regionales. Los precios históricos de la corteza al consumidor han aumentado pero al considerar los precios sin inflación, realmente han bajado. Se destaca que la mayor amenaza para las poblaciones es la intensidad de aprovechamiento y la práctica descuidada de la cosecha.</p>

RESUMEN:La relación maguey-hombre mesoamericano data de hace 10 mil años y el aprovechamiento de la planta para elaborar pulque se remonta aproximadamente a tres mil años. Esta agroindustria que floreció entre 1870 a 1900 ha decaído, lo que pone en riesgo el aprovechamiento tradicional y otros más rentables como la producción de inulina y jarabe de fructosa. Se documentó el aprovechamiento del maguey pulquero en localidades de Puebla y Tlaxcala, seleccionadas por muestreo aleatorio estratificado. Los datos taxonómicos, socioeconómicos, de gestión y actividades de productores, tlachiqueros y consumidores, se recabaron mediante entrevistas estructuradas y observación participativa. Se identificaron siete tipos de magueyes, cultivados en superficies promedio de tres ha; se describieron las labores culturales y actividades propias de los productores. El aprovechamiento sustantivo fue la elaboración del pulque a partir de magueyes de 10 a 14 años de madurez, mediante prácticas culturales tradicionales. Las herramientas para la producción, transporte de aguamiel y elaboración de pulque han sido sustituidas por materiales más resistentes y duraderos, que no necesariamente han mejorado el proceso y calidad del pulque. La duración del ciclo del cultivo, poca demanda de pulque, baja rentabilidad económica y ausencia de normas de protección para la planta, han provocado la disminución de la superficie de cultivo del maguey y la erosión del conocimiento del cultivo y su aprovechamiento. La permanencia del maguey pulquero dependerá de las acciones efectuadas en conjunto por las autoridades, los miembros de la cadena productiva e investigadores, y programas que incentiven el interés e incremento del cultivo de esta planta. ABSTRACT:The man-maguey relationship in Mesoamerica, and the use of the plant for pulque production goes back 10 000 years ago and three thousand years respectively. This agro-industry that flourished in the last third of the nineteenth century is at risk even its traditional use and others more profitable uses such as the production of inulin and fructose syrup with high demand in the international market. The use of maguey was documented and compared in localities of four municipalities of Puebla and Tlaxcala, selected by means of stratified random sampling. Data of taxonomic, socio-economic, management and activities of producers, "tlachiqueros" 207 and consumers, were collected through structured interviews and observational participation. The results showed seven types of maguey, on areas of three ha in average, imbricated with maize, barley and bean, of which cultural practices and activities proper of producers are described. The most important was the elaboration of pulque, using maguey plants from 10 to 14 years of age. The cultivation and use have been maintained over the years. The tools used for the recollection, transport and processing of aguamiel and production of pulque have been replaced by more resistant and durable materials, which have not necessarily improved the process and quality of p...

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Commercial harvests can threaten tree species harvested for their bark. Amphipterygium adstringens is a dioecious tree, endemic to the tropical dry forests of Mexico, where it is intensively harvested for its medicinal bark. Limited information hinders developing sustainable management strategies for A. adstringens. We assessed bark regeneration for male and female trees, and evaluated the effect of tree sex and diameter, debarking treatments and cutting seasons on bark regeneration and tree survival rates. Bark regeneration was higher for wet season harvested trees (vs. dry), regardless of their sex. Bark regeneration was higher on female than on male trees. There were significant interactions of harvest season, harvest treatment and tree sex diameter on bark regeneration and survival. Overall, the highest bark regeneration rates occurred in female trees with ≥20.1 cm diameter that were wet season harvested with a 50% debarking intensity. Consequently, wet season and intermediate intensity harvests appear to foster sound management, but we recommend against targeting exclusively a single demographic group (i.e., large female trees) due to potential negative impacts on species demography and bark supply. A grounded strategy for sustaining bark harvest would also need to take into account relevant aspects of local socio-ecological context, including harvest interactions with other land uses.

Background Most reports of domesticated plants that involve a domestication gradient or inter-specific hybridization in Mexico have focused on those used as food. This study provides knowledge about these processes in two aromatic medicinal plants, Agastache mexicana (Lamiaceae) and A. m. subsp. xolocotziana, widely used in Mexican traditional medicine for the treatment of gastrointestinal ailments and for their sedative effect. Different populations of A. mexicana along a gradient of domestication are found in the foothills of the Popocatepetl volcano of central Mexico, while in this same area the subsp. xolocotziana grows only in the cultivation, possibly a product of hybridization between A. mexicana and Agastache palmeri. This study links ethnobotanical, morpho-physiological, and phytochemical evidence to document the domestication of both taxa as well as elucidates the possible hybrid origin of the subsp. xolocotziana. Method We analyze three groups of data derived from (1) 80 semi-structured interviews aimed at documenting the selection criteria related to the use and management of A. mexicana; (2) a cultivation experiment under homogeneous conditions, evaluating 21 floral, vegetative, and seed characters (that were important according to ethnobotanical information) in 97 plants corresponding to 13 populations of the taxa under study; and (3) the chemical profiles of the essential oils of these plants by means of a thin-layer chromatography. Results By linking the three types of evidence, two evolutionary processes are distinguished: (1) A. mexicana occurs in the encouraged-cultivated phases of the domestication gradient and (2) A. m. subsp. xolocotziana may have originated through inbreeding depression or hybridization. These two cultivated plants show a domestication syndrome based upon organoleptic differentiation due to their dissimilar phytochemical composition and gigantism in flowers, seeds, and rhizomes (the last enhancing their asexual reproductive capacity). In addition to this, A. mexicana exhibits more intense floral pigmentation and foliar gigantism while subsp. xolocotziana presents floral albinism and partial seed sterility. Conclusion Two divergent evolutionary processes are reported for the domestication of A. mexicana as a result of the intensification of its use and management. The selection processes of these plants have resulted in alternation of the organoleptic properties based upon the divergence of the phytochemical composition. Also, gigantism has been selected in culturally preferred plant parts and in correlated structures. The preceding characteristics reinforce the joint use of these plants in infusion in Mexican traditionalmedicine for the treatment of gastrointestinal diseases and for their sedative effects.