RESUMENDurante la época seca de 2006 se registró el aprovechamiento del hábitat por el venado cola blanca (Odocoileus virginianus couesi) en la Sierra del Laurel de Aguascalientes. El objetivo de este estudio fue analizar, a través de regresión logística, algunos atributos biofísicos del hábitat que influyen en la probabilidad de que algunos sitios sean utilizados, en mayor o menor proporción, por el venado. El tipo de vegetación, la pendiente, la altitud y la distancia al agua influyeron de manera significativa (p<0.01) en la probabilidad de aprovechamiento del hábitat por el venado. Los umbrales de estas últimas tres variables se determinaron para una probabilidad de aprovechamiento alta p (y≥0.5) y variaron en función del tipo de vegetación. En términos generales, las mayores probabilidades de aprovechamiento se obtuvieron en el matorral subtropical. Para una probabilidad de aprovechamiento alta, este tipo de vegetación tuvo una densidad de 50 árboles de Ipomoea murucoides Roem & Schult y 350 arbustos de Eysenhardtia polystachya Ortega Sarg. por hectárea; así como una altura promedio del estrato arbustivo de 2.0 m. En virtud de que el matorral subtropical constituye el hábitat más escaso y amenazado por actividades agrícolas y ganaderas en la Sierra del Laurel, y con base en las evidencias aportadas por este estudio, es necesario promover acciones entre los dueños de la tierra para realizar una mejor gestión de este tipo de vegetación, que es de gran importancia para el venado en la región. Palabras clave: Venado cola blanca, Odocoileus virginianus couesi, hábitat, matorral subtropical, Sierra del Laurel, Aguascalientes, México. ABSTRACTHabitat use by the Coues white tailed deer (Odocoileus virginianus couesi) was documented during the dry season of 2006, in the Sierra del Laurel, Aguascalientes, Mexico. Based on logistic regression analyses, the objective of this study was to determine which floristic-structural and topographical features influence the probability of habitat use by the Coues deer. Vegetation, slope, altitude and distance to water were significant (p < 0.01) in the probability of habitat use. The thresholds for slope, altitude and distance were estimated for a high probability of use p (y≥0.5) and varied due to vegetation type. Sites on subtropical vegetation with 50 trees of Ipomoea murucoides Roem. & Schult by hectare and 350 shrubs of Eysenhardtia polystachya Ortega Sarg., and mean height of the shrub layer 191Acta Zoológica Mexicana (n.s.) 24(3): 191-212 (2008) over the 2.0 meters, had a probability of use greater than 50 percent. However this vegetation type is scarce and threatened by agricultural development in the Sierra del Laurel. The results of this research clearly point out the need to promote management and conservation strategies of this type of vegetation since it is the preferred habitat of the Coues deer, which in turn should be considered as an asset by the state holders and an option to derive additional income from hunting fees and other economic activities pertainin...

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The proper estimation of above-ground biomass (AGB) stocks of managed forests is a prerequisite to quantifying their role in climate change mitigation. The aim of this study was to analyze the spatial variability of AGB and its uncertainty between actively managed pine and unmanaged pine-oak reference forests in central Mexico. To investigate the determinants of AGB, we analyzed variables related to forest management, stand structure, topography, and climate. We developed linear (LM), generalized additive (GAM), and Random Forest (RF) empirical models to derive spatially explicit estimates and their uncertainty, and compared them. AGB was strongly influenced by forest management, as LiDAR-derived stand structure and stand age explained 80.9% to 89.8% of its spatial variability. The spatial heterogeneity of AGB varied positively with stand structural complexity and age in the managed forests. The type of predictive model had an impact on estimates of total AGB in our study site, which varied by as much as 19%. AGB densities varied from 0 to 492 ± 17 Mg ha−1 and the highest values were predicted by GAM. Uncertainty was not spatially homogeneously distributed and was higher with higher AGB values. Spatially explicit AGB estimates and their association with management and other variables in the study site can assist forest managers in planning thinning and harvesting schedules that would maximize carbon stocks on the landscape while continuing to provide timber and other ecosystem services. Our study represents an advancement toward the development of efficient strategies to spatially estimate AGB stocks and their uncertainty, as the GAM approach was used for the first time with improved results for such a purpose.

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-The objective of the present study was to determine the nutritive value, the presence of antioxidant compounds, and the antioxidant capacity of coffee pulp ensiled or non-ensiled. Dry matter (DM), crude protein (CP), ash, acid detergent fiber (ADF), neutral detergent fiber (NDF), and lignin, as well as the antioxidant compounds present in coffee pulp and their antioxidant capacity, were determined. A completely randomized design was used. Data were analyzed by analysis of variance. Ensiling of coffee pulp increased the CP content from 98.6 to 111.6 g kg −1 DM, NDF from 414.6 to 519.5 g kg −1 DM, ADF from 383.9 to 439.3 g kg −1 DM, and lignin from 122.9 to 133.6 g kg −1 DM. Caffeine decreased from 5.72 to 5.02 mg g −1 DM. Three antioxidant compounds were detected. Caffeic acid decreased due to ensiling (16.49 vs 14.69 mg g −1 DM). Gallic acid (2.88 vs 2.58 mg g −1 DM) and chlorogenic acid (62.12 vs 56.00 mg g −1 DM) did not differ, and there was similar antioxidant capacity of non-ensiled (215.66 µmol trolox g −1 DM) and ensiled coffee pulp (206.59 µmol trolox g −1 DM). Despite the decrease in the caffeic acid content due to the ensiling process, it is possible to use either ensiled or non-ensiled coffee pulp for animal feeding because of its high antioxidant capacity.

Carretera México-Texcoco, 56230 Montecillo, México vreyes@colpos.mx RESUMEN Con base en características morfológicas y anatómicas de conos, hojas y ramillas se evaluó el patrón geográfico de variación en poblaciones naturales del género Pseudotsuga en México. Las muestras de órganos vegetativos y reproductivos se colectaron en un total de 293 árboles procedentes de 19 localidades de las diferentes regiones geográficas en las cuales se distribuye el género en nuestro país. Se analizaron los caracteres considerados como importantes desde el punto de vista de la sistemática, de tal forma que fueran útiles para tratar de esclarecer los límites de los taxa de este género en México. El análisis de varianza mostró que existe una fuerte diferenciación entre las poblaciones en la mayoría de las variables consideradas, con 22 a 92% de la varianza total a este nivel. La región geográfica de procedencia tuvo un papel importante en la separación de las muestras, lo que implica la existencia de ecotipos diferentes de Pseudotsuga en el territorio de la República. Debido a que la variabilidad atribuible a los taxa putativos fue menor que la correlacionada con las regiones geográficas, se concluye que no existen bases morfológicas suficientes para separar las especies de Pseudotsuga propuestas para México con anterioridad.Palabras clave: componentes de varianza, diferenciación morfológica, ecotipos, México, Pinaceae, Pseudotsuga, taxa putativos. ABSTRACTUsing morphological and anatomical traits of cones, leaves and branchlets, the geographic pattern of variation was evaluated in natural populations of Pseudotsuga in Mexico. Vegetative and reproductive samples were collected from a total of 293 trees in 19

Zea mays and Sorghum bicolor are important crops for animal and human nutrition worldwide. In the Central Highland Valley of Mexico, both crops are extremely important, and research is aimed toward increasing yield, disease resistance, and crop adaptation from 1,900- to 2,700-m elevation. In a 3-year field breeding experiment (2004 to 2006), leaf blight and vascular wilt symptoms were frequently observed in contiguous plots of maize and sorghum crops in Montecillo, Mexico and maize plots in Tecamac, Mexico. To identify and characterize the causal agent of these symptoms, isolations were conducted on leaves from areas where healthy and diseased tissues converged. Leaf sections of 1 cm2 from both crops were disinfested, placed on casamino acid-peptone-glucose (CPG) medium, and incubated at 28°C. After 48 h, only yellow colonies were observed and 12 isolates were selected for further characterization. Physiological and biochemical tests indicated that the isolates were nonfluorescent on King's B medium, and API 50 CHE (bioMérieux, Marcy l'Etoile, France) revealed that they were negative for gelatin hydrolysis, indole production, acid production from raffinose and positive for utilization of glycerol, D-glucose, mannitol, arbutine, esculine, salicine, cellobiose, maltose, melibiose, D-fucose, and D-arabitol; all characteristics of Pantoea agglomerans. Further identification of these isolates was accomplished by DNA analysis. For DNA analysis, 1.4-kbp fragments of the 16S rRNA gene were amplified with primer set 8F/1492R (3) and sequenced with U514F/800R universal primers (2). Five sequences were obtained and deposited in GenBank (Accession Nos. EF050806 to EF050810). A phylogenetic tree was constructed using the UPGMA method (mega version 3.1). Results of the phylogenetic analysis grouped the species P. ananatis, P. stewartti, and P. agglomerans into three clusters. The five unknown sequences were grouped into the P. agglomerans cluster. There was a 98 to 99% similarity of the five 16S rRNA gene sequences with P. agglomerans strain type ATCC 27155. Pathogenicity of the 12 isolates was confirmed by injecting 108 CFU mL–1 of inoculum into stems of 3-week-old maize cv. Triunfo and sorghum cold tolerant hybrid (A1×B5)×R1 seedlings in the greenhouse at 28°C and 80% relative humidity. Also, seedlings were inoculated with water, nonpathogenic isolates of P. agglomerans from maize (GM13, and HLA1), and not inoculated as negative controls. Three replications were included for each isolate and control. All test strains developed water-soaked lesions on juvenile leaves at 8 days postinoculation and were followed by chlorotic to straw-colored leaf streaks and then leaf blight symptoms at 3 weeks postinoculation. All negative control seedlings did not develop symptoms. In addition, the 12 isolates were infiltrated at 107 CFU mL–1 into tobacco leaves that displayed a hypersensitive response at 4 days, indicating the presence of the type III secretion system (1). Isolates were reisolated, and the 16S rRNA gene fragments were 100% similar to their original isolate sequences. P. agglomerans has been reported to affect other crops, including chinese taro in Brazil (2007), onion in the United States (2006) and South Africa (1981), and pearl millet in Zimbabwe (1997); however, to our knowledge, this is the first report of P. agglomerans associated with leaf blight and vascular wilt symptoms in maize and sorghum in the Central Highland Valley of Mexico. References: (1) J. Alfano and A. Collmer. Annu. Rev. Phytopathol 42:385, 2004. (2) Y. Anzai et al. Int. J. Syst. Evol. Microbiol. 50:1563, 2000. (3) M. Sasoh et al. Appl. Environ. Microbiol. 72:1825, 2006.