Eduardo Estrada

Ethnobotany in the Cumbres de Monterrey National Park, Nuevo León, México

An ethnobotanical study in the Cumbres de Monterrey National Park (CMNP), Nuevo Leon, Mexico was conducted. In spite of the large area (1,773.7 km2), heterogeneous physiography, contrasting plant communities and high species diversity of the CMNP, very little was previously known about its useful plants. Based on 95 interviews with inhabitants of the region who were 35 years or older, we recorded ethnobotanical data of 240 species (comprising 170 genera and 69 botanical families), and 146 different uses. Most of the cited uses (98) were found to be medicinal ones.BackgroundAn ethnobotanical study in the Cumbres de Monterrey National Park (CMNP), Nuevo Leon, Mexico was conducted. In spite of the large area (1,773.7 km2), heterogeneous physiography, contrasting plant communities and high species diversity of the CMNP, very little was previously known about its useful plants. Based on 95 interviews with inhabitants of the region who were 35 years old or older, we recorded ethnobotanical data of 240 species (comprising 170 genera and 69 botanical families), and 146 different uses. Most of the cited uses (98) were found to be medicinal ones.MethodsNinety five inhabitants 35 years old and oldest were interviewed to know what are the main plant uses in the Cumbres de Monterrey National Park.Results and discussionTwo hundred and forty species, 170 genera, and 69 families of useful plants and 146 different uses were recorded. We found most of the uses to be medicinal (98), while the rest (48) represent various purposes. Herbaceous plants are the most used, followed by shrubs and trees.

Post-Harvest Growth of Lechuguilla (Agave lecheguilla Torr., Agavaceae) in Northeastern Mexico

Extraction of lechuguilla fiber (Agave lecheguilla) is often the only source of income for some rural inhabitants in arid zones of Mexico. A model for biomass estimation of lechuguilla by nondestructive techniques was developed and then applied to evaluate whether traditional harvesting had an effect on (1) biomass production of the bud (part of the plant traditionally collected to obtain fiber) and (2) plant density. Six months after harvesting, biomass production was higher for buds of harvested plants than for buds of unharvested plants, but there were no differences 1 year after harvesting. Number of new plants was not affected by harvesting. Hence it appears that at least in the short term the common practice for extracting lechuguilla fiber does not affect population density, but significantly increases growth of central buds.ResumenLa extracción de la fibra de lechuguilla (Agave lecheguilla) es frecuentemente la única fuente de ingresos para algunos campesinos de las zonas áridas de México. Se desarrolló un modelo para la estimación de biomasa de lechuguilla por métodos no-destructivos. Éste fue después aplicado para evaluar si la forma tradicional de cosecha tiene un efecto en (1) producción de biomasa del cogollo (parte de la planta tradicionalmente cosechado para obtener fibra) y (2) densidad de plantas. Dentro de los primeros 6 meses posteriores a la cosecha la producción de biomasa fue mayor para los cogollos de las plantas cosechadas que para aquellos de las plantas control, sin embargo no se encontró diferencia un año posterior a la cosecha. El número de plantas nuevas no se vio afectado con la cosecha. En este estudio mostramos que, si bien la práctica común de extracción del cogollo para la obtención de fibra no afectó la densidad de la población de lechuguilla en el corto plazo, sí incrementó significativamente el crecimiento del cogollo.

The influence of land use on desertification processes

Abstract Site degradation occurs mainly through deterioration of the soils capacity to capture and store water, as well as the loss of organic matter or the accumulation of salts or other toxic substances in the soil. This degradation process, leading to the reduction of the biotic potential of the site, is known as desertification. In this study, changes in bulk density, organic matter, and electrical conductivity are used as indicators of desertification in northeast Mexico. The hypotheses put forward here are that degradation processes are affecting extensive areas of the region, and that the type of processes and their magnitude differ according to specific land uses. Thirty-one sites under different land use systems (agriculture, rangeland, induced grassland, and a protected site) were sampled for bulk density, organic matter, and salinity. Soil samples for bulk density estimation were collected in 1996, 1997, and 1999, while those for organic matter and salinity were taken in 1993, 1997, and 1999. Soil bulk density and organic matter showed significant changes across time in rangeland sites. None of the sites showed significant changes in salinity. Organic matter was similar in agriculture, rangeland, and grassland sites across dates. Soil bulk density was similar in grasslands and rangelands and lower in agriculture sites. Values of organic matter were lower and those of soil bulk density were higher when compared to a protected native vegetation site.

Abundance of Seedlings in Response to Elevation and Nurse Species in Northeastern Mexico

Abstract Abundance of seedlings of functional groups (woody plants, grasses, and forbs) was measured monthly for 2 years under 10 replicates of three nurse plants (Caesalpinia mexicana, Cordia boissieri, and Ebenopsis ebano) at 90, 350, 540, and 670 m above sea level in northeastern Mexico. Across elevations, there were more forbs than grasses and more grasses than woody plants. Grasses and forbs were denser in spring, summer, and autumn than in winter; greatest abundance of seedlings from woody plants occurred during summer and autumn. Abundance of seedlings across elevations was greater under E. ebano and C. boissieri than under C. mexicana. For all species and for functional groups separately, abundance of seedlings was greater at higher elevations than at lower elevations.

Physical Crust Does Not Affect Soil Seed Bank

We compared density and species of a seed bank in (1) a soil with a physical crust, (2) a soil with low plant cover with signs of erosion, and (3) a soil covered by dense vegetation with no evidence of erosion in Northeastern Mexico. From the 33 identified species, there were more seeds in the soil of the area without evidence of erosion (1,900 seeds m−2 from 30 species), no differences were found between the soil with a crust (88.8 seeds m−2 seeds from 12 species) and the eroded soil without a crust (62.7 seeds m−2 from 10 species).

The confusing identity of Agave wislizeni (Agavaceae)

The use of the name Agave wislizeni Engelm. is controversial. There is uncertainty about the type locality, the original description is vague, and the illustrations and specimens that have been associated with this name have only added further to the confusion. According to the description and possible type localities, A. wislizeni could be confused with what is now known as A. parryi Engelm., A. parrasana A. Berger or A. ovatifolia Starr & Villarreal. However, because A. wislizeni was originally proposed as a substitute name for A. scabra Salm-Dyck, its identity can be resolved as a synonym of A. asperrima Jacobi.