Angélica Romero-Manzanares

Highlights for Agave Productivity

Agaves can grow in marginal arid and semiarid lands where their special ecological and physiological adaptations to environmental conditions give them the potential to produce substantial biomass. Agave americana was the first agave species shown to be a Crassulacean Acid Metabolism plant, with CO2 uptake occurring primarily at night and with high water‐use efficiency (photosynthesis/transpiration). A. salmiana and A. mapisaga can have high nocturnal net CO2 uptake rates and high productivities averaging 40 tonnes dry weight ha−1 yr−1. Agaves can benefit from the increases in temperature and atmospheric CO2 levels accompanying global climate change. An Environmental Productivity Index can predict the effects of soil and environmental factors on CO2 uptake and hence on the regions appropriate for cultivating agaves. In turn, their increased cultivation can support the production of innovative earth‐friendly commodities that can be used as new bioenergy feedstocks.

Participative generation of local indicators for conservation in Morelos, Mexico

Useful indicators for identification of plant species of importance to conservation were identified with the participation of informants from the town of Temimilcingo. The inhabitants of this central Mexican indigenous community use resources from the dry-deciduous forest within the Sierra de Monte Negro State Reserve. Semi-structured interviews and workshops were used, indicators and criteria were established, and local dimensions were identified. Both qualitative and quantitative methods were employed. The cultural dominance in criteria and indicators was calculated and submitted to descriptive and multivariate analysis. Twenty-four indicators, nine criteria and five dimensions related to ecology, trade, use, categories of use (food, fuel, etc.), medicinal use (e.g. treat respiratory or digestive illness), and perceptions were identified. Indicators of Destructive Use and Scarcity were common among species, while the influence of Medicinal Use and its Perception varied. Indicators were connected to kinship, distribution of activities according to gender, level of interaction with external society and level of knowledge of plants. Some local indicators and scientific conservation indicators coincided. During the selection of species of importance to conservation, it should be possible to incorporate non-scientific indicators of Medicinal Use and Perception with scientific indicators. This allows for local participation in efforts toward sustainable development.

Plants of Local Interest for Medicinal and Conservation Purposes in Morelos, Mexico

Abstract This study attempts to test whether local selection of species, whose conservation is considered a priority at the community level, has the potential of contributing to public health care showing vegetal species valuable in traditional medicine. This work was carried out in Temimilcingo, a community immersed in the deciduous forest in the Sierra de Monte Negro State Reserve, Morelos, Mexico. Interviews and workshops were used to register Traditional Ecological Knowledge of participants. Distribution of knowledge related to plants used by informants and its social valuation was estimated, and later on compared using Multivariate Methods (Classification and Ordination). Participants selected 14 late and mid serial species distributed in the deciduous forest whose future conservation they felt should be guaranteed. Twelve species have a traditional medicinal use that is closely related to the Morelos’s state main causes of morbidity and mortality, and 10 of them have been already corroborated by scientific protocols. Therefore, these species should be promoted in the plans for sustainable development of indigenous communities.

Effect of Slope and Aspect on the Associated Flora of Pinyon Pines in Central Mexico

Abstract To test the hypothesis that Mexican pinyons (Pinus cembroides) and Johannis pines (P. johannis) grow under different environmental conditions, the flora associated with both species was sampled along two 20-m perpendicular transects at 40 sites. Patterns were analyzed with the two-way-indicator-species program, which yielded six groups with Mexican pinyons dominating xeric sites and Johannis pines dominating mesic sites. Other groups of species corresponded to transition from mesic to xeric sites. We used canonical-correspondence analysis to explore the effect of slope and aspect on species and indirectly related them to an underlying moisture gradient. The first ordination axis indicated that aspect explained 59% of the variation, and the second axis, representing slope, explained 41%.

Mechanical properties of wood of two Mexican oaks: relationship to selected physical properties

The relationship between 27 mechanical parameters and density, shrinkage coefficients, moisture content, anisotropy ratio, and the fiber saturation point (FSP) in small specimens of Quercus crassifolia Humb. & Bonpl. and Q. laurina Humb. & Bonpl. wood, from Oaxaca, Mexico, is described. Wood from both oaks displayed low dimensional stability, while mechanical testing results revealed a strong material in most forms of stress, as well as a high impact-resistance wood. Wood mechanical properties in dry and green state were positively correlated with density, shrinkage coefficients, and FSP. Density was generally the single best predictor for mechanical strength, although the modulus of elasticity was a better predictor of the modulus of rupture in the bending tests. Univariate models to predict mechanical properties using the best regressor of the physical properties gave R2 values from 0.104 (p = 0.015) to 0.494 (p < 0.001), whereas multivariate regression significantly increased the predictive power of the models, with R2 values from 0.190 (p = 0.004) to 0.646 (p < 0.001).

Initial floristic composition of rehabilitated gullies through bioengineering in the Mixteca Region, Sierra Madre del Sur, Mexico

Re-vegetation plays a fundamental role for erosion control and plant recovery in lands affected by gully erosion. Bioengineered practices facilitate the gullies rehabilitation. Objectives of the research were: 1) Identify taxonomically the pioneer vegetation on each gully section; 2) Characterize vegetation distribution preferences and 3) Assess structural/ functional traits to recognize erosion control key species. Bioengineering was applied in a watershed belonging to Sierra Madre del Sur, at Oaxaca, Mexico, on eight gullies, with local support and minimal investment. “La Mixteca” is a poor ecological and socio-economic region, comparable to other regions of the world. The Initial Floristic Composition (IFC) inventory is the baseline of the successional process. The transect method was used to determine the colonization of species. Cover abundance of registered species was estimated using the semi-quantitative scale of Braun-Blanquet. This procedure was repeated in five different positions (floor, hillslopes and tops), in the cross section of the gully. Through correspondence analysis and clustering, the distribution of species was analyzed. Adequate responses were obtained in soil retention (quantity) and plant cover (existence and diversity); as measurable indicators of the bioengeneering works efficiency. Occupation of soil by native species from the Tropical Deciduous Forest was favored using live barriers. We detected species guilds with spatial distribution preferences in the gullies cross section. Plant cover characterization includes: native colonizer species, herbaceous, shrubby and trees of the forest community bordering the gully area, with cover abundance and structural/functional traits, useful to protect degraded areas. This spatial occupation process of plants responds to a secondary succession in gullies, where the proposed IFC model is correctly represented through bioengineering. Natural establishment of plants was successful by traits of species such as extensive root system and sexual/vegetative reproduction.

Traditional and formal ecological knowledge to assess harvesting and conservation of a Mexican Tropical Dry Forest

This research integrates Traditional and Formal Ecological Knowledge (TEK / FEK) of a Tropical Dry Forest in central Mexico, in order to assess harvesting and conservation of the non-timber forest species. We were interested in: knowing the structure and diversity of the forest community; identifying which are the tree resources of common interest to the users through participatory workshops. A further interest was to identify those resources which are important to local people in terms of preservation; explaining the relationship of the species with some environmental factors; and visualizing which management practices endanger or facilitate the conservation of species. Studied areas were defined and labelled on a map drawn by local informants, where they indicated those plant species of common interest for preservation. Ethnobotanical techniques were used to reveal the TEK and assess harvesting and conservation of the species. With the FEK through community and population ecology, we detected the importance of five environmental factors, obtained various ecological indicators of the vegetation, and studied the population structure of the relevant species. The FEK was analyzed using descriptive and multivariate statistics. As a result, low density and small basal area of trees were registered. Species richness and diversity index were similar to other natural protected areas in Mexico. Tree species harvested shown an asymmetric distribution of diameters. Harvesting, elevation, and accessibility were the most influential factors on tree density. FEK demonstrated that TEK is helpful for the assessment of forest harvesting. Ecological analysis complemented the local knowledge detecting that Lysiloma tergemina is a species non-identified for the people as interesting, although we discover that it is a threatened species by over-harvesting. Haematoxylum brasiletto was identified as important for conservation due to its scarcity and medicinal use. Our results advanced on how the traditional harvesting of tree community has contributed to preserve diversity, when comparing with protected areas. Discrepancies between both kinds of knowledge should be reconciled for contributing to the preservation of priority resources by the local society.

Architectural and morphological variation of Hintonia latiflora (Rubiaceae) in relation to bark harvest and environmental factors.

Hintonia latiflora is a rare ecologically and economically important species from the Tropical Deciduous Forest of the Balsas Basin, Mexico, whose bark is traded as medicinal. Debarking practices have modified the shape of plants, their architecture and morphometry; but it is unknown if some topographic and edaphic factors may also influence in these attributes. Here we propose that the ecological conditions of this species distribution and harvesting areas, may determine the morphometric characteristics and the individuals variation in their architecture. To test this hypothesis we assessed the relationship of topographic and edaphic factors on the morphological characteristics of saplings (n = 143) and adults (n = 117), in eight harvesting areas of H. latiflora . The harvesting areas, with a surface of 0.6 ha, were selected randomly with the support of participatory mapping elaborated by gatherers of the study site. Data were analyzed using principal components (PCA) and canonical correspondence (CCA) analyses. The first three PC explained 92.1 % of the morphological variation; height, basal diameter, and coverage, explained morphometric differences in both, saplings and adults, in all eight harvesting zones. The terrain slope, slope orientation, soil depth and stoniness, were ecological factors statistically related with morphometric differences. A lower terrain slope, little stoniness, soil depth, slope orientation E-W in saplings (azimuth 90˚-270˚) and N-S in adults (azimuth 0˚-180˚) were the factors associated to height, number of basal branches, basal diameter and coverage of H. latiflora . Areas with higher harvesting intensity were composed by monopodic trees and some reiterated basitone individuals; the adults of these areas also had more fruits. At these sites, plants of H.latiflora were more abundant and produced more bark, but the high-intensity of harvesting, changes plant architecture, forming shrubby, multi-stemmed individuals, that originally were mesotone trees. Areas with lower harvesting intensity were characterized by steep slopes, shallow and rocky soils, and were dominated by basitone trees of smaller size, thin and scarce in the area. These sites are the least recommended for harvesting, because they produce less bark per tree, and serve to preserve the species at the site. Based on these results, we can develop restoration programs in areas affected by commercial harvesting, establish forestry plantations in key sites to ensure the establishment and development of individuals with desirable characteristics for bark harvesting and contribute to in situ conservation of H. latiflora in the Alto Balsas Basin.

Variación arquitectónica y morfológica de Hintonia latiflora (Rubiaceae) en relación a la cosecha de corteza y factores ambientales

Hintonia latiflora es una especie ecologicamente rara y economicamente importante del bosque tropical caducifolio de la Cuenca del Balsas, Mexico, cuya corteza se comercializa como medicinal. Las practicas de descortezado han modificado la forma de las plantas, su arquitectura y morfometria. Se desconoce, si ademas, existe influencia de factores topogaficos y edaficos sobre estos atributos. Se propone que las condiciones ecologicas en las areas de distribucion y cosecha determinaran las caracteristicas morfometricas y la variacion de la arquitectura de los individuos. Para probar esta hipotesis, evaluamos la relacion de factores topograficos y edaficos en diferentes caracteristicas morfologicas de juveniles (n = 143) y adultos (n = 117) de ocho zonas de cosecha de H. latiflora. Las zonas de cosecha, con una superficie de 0.6 ha, fueron seleccionadas al azar con el apoyo de mapas participativos elaborados por los recolectores del area de estudio. Los datos fueron analizados mediante componentes principales (ACP), y correspondencia canonica (ACC). Los primeros tres CP explicaron el 92.1 % de la variacion morfologica; la altura, diametro basal y cobertura fueron las variables que explicaron las diferencias morfometricas entre juveniles y adultos en las ocho zonas de cosecha. La pendiente del terreno, orientacion de la pendiente, profundidad del suelo y pedregosidad, fueron los factores ecologicos estadisticamente relacionados con las diferencias morfometricas. Una menor pendiente, poca pedregosidad, profundidad de suelo, orientacion E-O en juveniles (azimut 90˚-270˚) y N-S en adultos (azimuth 0˚-180˚), fueron los factores asociados a mayor altura, numero de ramas basales, diametro basal y cobertura en H. latiflora. Las zonas con mayor intensidad de cosecha estuvieron integradas por arboles monopodicos y algunos individuos basitonos reiterados. Los adultos de estas zonas tuvieron mayor numero de frutos. En estos sitios, las plantas de H. latiflora fueron mas abundantes y productivas para corteza, pero la alta intensidad de cosecha influyo en la arquitectura vegetal, formando individuos arbustivos multirramificados que originalmente fueron mesotonos. Las areas con menor intensidad de cosecha estuvieron caracterizadas por pendientes abruptas, suelos superficiales y pedregosos, dominadas por arboles basitonos de menor talla, delgados y escasos en el area. Estos sitios son los menos recomendados para cosecha, debido a que producen menos corteza por arbol, pero sirven para mantener a la especie en el lugar. Con base en estos resultados, podemos desarrollar programas de rehabilitacion en areas afectadas por la explotacion comercial, establecer plantaciones forestales en sitios clave para asegurar el desarrollo de individuos con caracteristicas deseables para cosecha de corteza y contribuir a la conservacion in situ de H. latiflora en la Cuenca del Alto Balsas.

Morphological variation related with environmental factors in endemic and threatened Jatropha species of Tehuacan-Cuicatlan, Mexico

Jatropha spp. from Mexico includes high species richness and endemism; five species inhabit in the Tehuacan-Cuicatlan Biosphere Reserve (TCBR), and they are important resources as food, medicine and biofuel. The assessment of morphological and agronomic characteristics is essential to identify, use and maintain plant genetic resources. Given the lack of information on the morphological variability of Jatropha species in relation to environment, the objective was to analyze the influence of physiographic, climatic, and anthropogenic factors in the morphological variability of the species: Jatrophaneopauciflora and J. rzedowskii, both not-endangered; J. oaxacana, special protection; J. ciliata and J. rufescens, both endangered in the Reserve. Twelve quantitative morphological variables were measured in 24 populations of these species; 14 environmental variables were registered, and the disturbance index in the sites was estimated. The information was analyzed with Principal Components Analysis (PCA), Cluster Analysis and Canonical Correspondence Analysis (CCA). PCA detected interspecific variation: J. ciliata and J. rufescens have longer and broader leaves and longer flowers, while the other three species have smaller leaves and flowers. J. oaxacana population has intermediate size of leaves, fruits and seeds, compared with those of J. neopauciflora and J. rzedowskii. CCA detected intra-specific variation among the populations of J. neopauciflora and J. rzedowskii, which were separated in two groups due to fruit and seed size. Axis 1 of CCA correlated positively with altitude and annual temperature range, and negatively with mean annual temperature; at the intra-specific level, both species are adapted to variations of temperature and altitude.