Humberto Suzán-Azpiri

Black-Tailed Prairie Dogs, Cattle, and the Conservation of North America’s Arid Grasslands

Prairie dogs (Cynomys spp.) have been eliminated from over 95% of their historic range in large part from direct eradication campaigns to reduce their purported competition with cattle for forage. Despite the longstanding importance of this issue to grassland management and conservation, the ecological interactions between cattle and prairie dogs have not been well examined. We address this issue through two complementary experiments to determine if cattle and prairie dogs form a mutualistic grazing association similar to that between prairie dogs and American bison. Our experimental results show that cattle preferentially graze along prairie dog colony edges and use their colony centers for resting, resembling the mutualistic relationship prairie dogs have with American bison. Our results also show that prairie dog colonies are not only an important component of the grassland mosaic for maintaining biodiversity, but also provide benefits to cattle, thereby challenging the long-standing view of prairie dogs as an undesirable pest species in grasslands.

THE ROLE OF URBAN VEGETATION IN TEMPERATURE AND HEAT ISLAND EFFECTS IN QUERÉTARO CITY, MEXICO

Alteration of climatic conditions and the urban heat island effect (UHI) are consequences of increased human population and activities in urban zones. Determining the magnitude of the UHI is important to improve urban planning in medium-size cities like Queretaro. Increase and conservation of vegetated areas is a mitigation option for UHI. Here we characterized both the UHI and the role of vegetation cover over temperature regularization in urban zones. Four local climatic zones were defined: three urban and one rural, each with two plots with low and high canopy cover defined by their average leaf area index (0.5 and 2.0, respectively). Air temperature and relative humidity were measured with data loggers at a 30 min time step from June 2012 to May 2013. Climatic data from six weather stations was also analyzed. Daily mean temperature increased at a rate of 0.75 oC per decade ( r 2 = 0.38, P < 0.0001), and this was related to population dynamics ( r 2 = 0.52, P < 0.0001). Patterns of air temperature defined a cold and a warm season: July to March and April to June for maximum temperature, and November to March and April to October for minimum temperature. The difference between cold and warm seasons was 5 oC (P < 0.0001). The minimum temperature was similar between canopy cover levels. However, relative humidity was higher in high canopy cover plots. The relationship between UHI and the pervious surface fraction of the city was inversely proportional. The UHI ranged from 0.1 to 5 oC and this magnitude was similar between the warm and cold seasons. Vegetation with high canopy cover had lower temperature at 17:00 LT and higher at 9:00 to 10:00 LT during the warm season. Increasing the urban zone canopy cover by 50% would reduce the UHI by 2.05 oC. In conclusion, vegetation with higher canopy cover improved environmental conditions in terms of relative humidity and regularization of extreme temperatures during the warm season.

Desarrollo de Pinus pseudostrobus bajo distintos ambientes de crecimiento en jardín común

A partir de un analisis de componentes principales (ACP), se plantea la interpretacion y clasificacion de tres ambientes de competencia sobre el desarrollo de individuos de P. pseudostrobus integrando resultados previamente publicados dentro del mismo ensayo; las variables evaluadas fueron: el crecimiento (altura y diametro a la base del tallo), produccion de clorofila (cantidad de pigmentos de clorofila a y b), supervivencia, produccion y distribucion de biomasa total, raiz, rama, hoja y tallo, y arquitectura de crecimiento (largo de rama y altura de insercion de la primera rama) en familias de medios hermanos de P. pseudostrobus evaluados en un ensayo de jardin comun a 10 meses de edad bajo tres ambientes de competencia. (I) baja densidad inter-familiar (0.24 × 0.12 m), (II) alta densidad inter-familiar (0.12 × 0.06 m) y (III) alta densidad intra-familiar (0.12 × 0.06 m). Se estimo que los tres componentes con mayor peso (CP) explican el 82.9% de la variacion total. El componente principal de mayor varianza se interpreta como crecimiento (CP1), agrupando a las familias por ambiente de competencia; al aumentar la densidad de plantacion, posteriormente, las familias se agrupan por la capacidad de supervivencia y por la plasticidad fisiologica (CP2). Finalmente, la diferencia entre los ambientes la hace la plasticidad fenotipica de las familias como respuesta al ambiente de competencia (cambios en la arquitectura) (CP3). Los resultados evidenciaron un elevado nivel de plasticidad fenotipica de P. pseudostrobus y se hace hincapie en la importancia de la seleccion de ambientes y de genotipos acordes para aumentar la adaptacion y productividad en los programas de mejora.

Ethnomycological knowledge in three communities in Amealco, Quéretaro, México

BackgroundFungi have multiple uses in temperate areas of México, but an important decrease in the traditional knowledge of uses and customs of mushrooms becomes a fundamental issue for fungi conservation. However, only few studies quantify the traditional ethnomycological knowledge in México, and this study is the first quantitative report for Querétaro, a central state with both Otomí and Mestizo communities and a high fungi diversity.MethodsThe present study was conducted registering traditional knowledge on the use and consumption of mushrooms in three Hñähñu (Otomí) communities (Tesquedó, Xajay, and Tenasdá) in Amealco de Bonfil, Querétaro, México, between August 2013 and November 2014. We conducted a stratified sampling, where uses common Hñähñu and Spanish names, and eight quantitative variables that conform the “Edible Mushrooms Cultural Significant Index” (EMCI) were recorded from 100 informants. For the classification and ordination analysis of species and uses, we used multivariate techniques such as cluster, multidimensional scaling, and principal components (PC).ResultsThirty-three mushrooms species were registered, most of them used for consumption by households, few aimed for commercial purposes, one species is medicinal, another has veterinary, and other ludic uses (as a toy). The three species with the highest EMCSI were Amanita basii, Fistulinella wolfeana, and Lactarius indigo. Edibility was the main use detected in the survey, and people harvested mushrooms provided by the forest mainly during the rainy season. We observed that mushroom searching and collection are activities that strengthen the family ties and are crucial for the transfer of this knowledge through generations. Cluster analysis separates groups according to different values in EMCSI variables, and principal components ordinate the species by frequencies (PC1) and traditions (PC2).ConclusionsThe current state of knowledge in the studied communities is strong, especially among women, but with a tendency to disappear due to migration and lack of interest among new generations. Future quantitative studies are important to analyze tendencies of the traditional ethnomycological knowledge transferred to new generations.