Riparian Zones are considered biodiversity and ecosystem services hotspots. In arid environments, these ecosystems represent key habitats, since water availability makes them unique in terms of fauna, flora and ecological processes. Simple yet powerful remote sensing techniques were used to assess how spatial and temporal land cover dynamics, and water depth reflect distribution of key land cover types in riparian areas. Our study area includes the San Miguel and Zanjon rivers in Northwest Mexico. We used a supervised classification and regression tree (CART) algorithm to produce thematic classifications (with accuracies higher than 78%) for 1993, 2002 and 2011 using Landsat TM scenes. Our results suggest a decline in agriculture (32.5% area decrease) and cultivated grasslands (21.1% area decrease) from 1993 to 2011 in the study area. We found constant fluctuation between adjacent land cover classes and riparian habitat. We also found that water depth restricts Riparian Vegetation distribution but not agricultural lands or induced grasslands. Using remote sensing combined with spatial analysis, we were able to reach a better understanding of how riparian habitats are being modified in arid environments and how they have changed through time.

The dusky rattlesnake, Crotalustriseriatus, used to be very abundant in many parts of the highlands of central Mexico, but with the increasing human population and associated activities, the rattlesnake habitats and populations have suffered drastic reductions and fragmentation. At the moment, the most important habitat features, associated with the presence of C.triseriatus, the current potential distribution and the landscape connectivity amongst the populations of the State of Mexico and Mexico City, are unknown. Therefore, we used the maximum entropy modelling software (MAXENT) to analyse the current potential distribution and most important habitat features, associated with the presence of the species. The variables with the highest contribution to the model were: proportion of Abies forest, minimum temperature of coldest month, maximum temperature of the warmest month, proportion of Pinus forest and annual precipitation. Furthermore, we found connectivity corridors only within mountain chains. Our results highlight the necessity for conserving the patches of Abies forest and preserving the populations of C.triseriatus and the connectivity of the landscape.

Diversas actividades humanas como la ganadería han transformado gran parte de la superficie terrestre, provocando cambios en todos los ecosistemas, incluyendo las áreas prioritarias para la conservación, como el caso de Sierra Libre, donde la principal actividad económica es la ganadería extensiva, cuyas acciones de manejo ocasionan la sustitución de vegetación natural por la introducción de pastos exóticos como el zacate buffel. El objetivo para este trabajo fue: generar clasificaciones de cobertura/uso de suelo mediante percepción remota y cuantificar el cambio en la cobertura entre 1993 y 2011, con el fin de evaluar las modificaciones del paisaje asociadas a la introducción y permanencia de praderas de buffel en Sierra Libre. Se observó intercambio entre pastizales Inducidos y Mezquital, resultando en una ganancia neta de 4,049 ha de pastizales; sin embargo, el intercambio entre Matorral Subtropical y Pastizales resulto en una pérdida neta de 3,313 ha de los mismos, entre 1993 y 2011. Contrario a lo esperado, los pastizales inducidos, no aumentaron considerable en extensión entre 1993 y 2011. Esto sugiere la necesidad de contabilizar las áreas cubiertas por zacate buffel y replantear las teorías relacionadas a la utilidad de especies exóticas para forraje en la zona central de Sonora.

Ecología térmica y riesgo de extinción ante el cambio climático de Gonatodes concinnatus (Squamata: Sphaerodactylidae), una lagartija endémica de la Amazonía occidental Thermal ecology and extinction risk due to climate change of Gonatodes concinnatus (Squamata: Sphaerodactylidae), an endemic lizard from western Amazonia