RESUMENEn las zonas áridas de México habita la candelilla (Euphorbia antisyphilitica), especie con importancia social y económica, pero cuya disponibilidad no está bien definida. El objetivo de este trabajo fue estimar su distribución potencial y abundancia en el norte del estado de Zacatecas. Para la distribución potencial se realizó un modelado mediante el algoritmo MaxEnt ® , donde se usaron 18 registros de presencia: 8 históricos y 10 propios, así como 27 variables predictivas. Se cotejó en campo la presencia mediante 29 puntos aleatorios en el área con distribución potencial y otros 19 fuera de ella. La densidad poblacional se estimó mediante parcelas, se midió la talla de los ejemplares y se consideraron las variables: tipo de vegetación y de suelo, altitud y pendiente del terreno y se realizó la prueba de Kruskal-Wallis. El modelo presentó buena predicción (AUC = 0.920), donde 11 variables contribuyeron con 82.1% en la distribución potencial y las más importantes fueron: tipo de vegetación, exposición, pendiente, altitud y cobertura vegetal. La distribución potencial se encontró en 19.2% del total del área de estudio; la densidad poblacional fue de 295 767.3 individuos por kilómetro cuadrado, influida significativamente por el tipo de vegetación y altitud. La talla de las plantas fue significativamente menor en pendiente escarpada. En 37.9% de los puntos de validación con distribución potencial hubo resultados positivos de presencia de la especie, sin embargo, en 10.5% fuera del área de distribución potencial también apareció. Se concluye que mediante la utilización del algoritmo MaxEnt ® se puede modelar la distribución potencial de plantas silvestres, como la candelilla; la distribución potencial fue discontinua y menor a 20%. ABSTRACTThe candelilla (Euphorbia antisyphilitica) grows in arid regions of Mexico, having social and economic importance, although its availability is not clearly defined.

Introduction:The ocelot (Leopardus pardalis) is a Neotropical cat which is threatened by illegal hunt and habitat destruction in the Mexican territory. Mexican and American authorities are interested in promoting their conservation. The MaxEnt algorithm allows modeling the potential distribution of elusive species, for instance, the ocelot. This has been based on trustable presence records and some other information about the habitat condition. This work was developed with the aim of generating important information about the species in Northeastern Mexico, especially, with the purpose of determining its potential distribution. Methods:Our study was conducted in six physiographic subprovinces in the Mexican states of Tamaulipas and San Luis Potosí. Sixty-trhee recent records about the ocelot were obtained, 41 through literature and 22 from field surveys , between May 2006 to May 2009. In order to develop a prediction model which let us know the animal potential distribution, twenty-seven bioclimatic, topographic, vegetation and anthropic variables were used through the MaxEnt software. Results:The model AUC was of 0.8221 ± 0.009. The most related variables about the ocelot presence were: precipitation of wettest month and quarter, vegetation cover, vegetation type, terrain elevation, precipitation of coldest quarter, terrain slope, human population density, and distance to roads. The potential distribution area overs 20.8 % of the study area. The physiographic subprovinces showing the highest potential distribution were: llanuras y lomerios (7.4 %), Carso Huasteco (4.8 %), Gran Sierra Plegada (4.5 %), and sierras and llanuras occidentales (3.4 %). The llanura costera Tamaulipeca subprovince showed lower potential distribution; meanwhile, llanuras de Coahuila y Nuevo Leon and sierras y llanuras del norte de Guanajuato were not suitable distribution for ocelot. Discussions and conclusions:In order to obtain the ocelot potential distribution model we use recent information collected through field work and surveys. Through this, we could achieve a robust model, where were relevant both bioclimatic and landscape variables. There are patches of habitat important in size and quality for ocelot. The physiographic subprovinces with the roughest landscape were the ones where the highest presence of the species. This study complements the ocelot distributional range in Northeastern Mexico and providing important information about the habitat quality in that portion of the country, as well as the difficulty to possible connectivity between Mexico and USA.Keywords: camera trap; field survey; huasteca region; MaxEnt; neotropical cats. Introducción:El ocelote (Leopardus pardalis) es un felino neotropical que se encuentra amenazado en México por la cacería ilegal y la destrucción de su hábitat. Existe interés de las autoridades de Estados Unidos y de México para conservarlo. El algoritmo MaxEnt permite modelar la distribución potencial de especies elusivas, como el ocelote, con base en registros confiables de presencia, e infor...

Persistence and recovery of rare species in developing regions with limited protected areas depends upon their adaptability to human-altered habitats. The jaguarundi (Herpailurus yagouaroundi) is classed as threatened in Mexico, and knowledge of its distribution and environmental correlates is necessary for informed recovery efforts. However, little is known of jaguarundi habitat or distribution in interior Mexico, including the state of San Luis Potosí (SLP). We conducted 96 semi-structured interviews around communities, ejidos, and ranches throughout SLP to obtain records of jaguarundi presence and identify environmental correlates and site attributes associated with its occurrence. We evaluated interviews using analytical criteria of credibility, and collected habitat information from 50 reliable occurrences from three of the four geographic regions of SLP. Compared to the SLP landscape, jaguarundi occurrences were located closer to water, closer to roads, at lower elevation, marginally closer to communities, and in areas with greater total edge, edge density, and number of landscape patches. Jaguarundi showed preference for mosaics of tropical forest, agricultural, grassland, and urban (i.e., any community) cover types. Relatively dense hiding or ambush cover was usually present at occurrence sites. Collectively, maximum entropy modeling and logistic regression modeling predicted similar and high likelihood of jaguarundi presence in regions characterized by mosaics of tropical forest, agriculture, grassland, or urban cover types <500 m in elevation and <2 km from roads. These mosaic landscapes tended to be relatively close to communities of moderate population densities and water, and typically support higher small prey densities than less fragmented areas. Jaguarundi were adaptable to at least light–moderate human-related disturbance, and may be benefitted by it because of increased edge and habitat mosaics.

Objective: To determine the diet of the desert bighorn sheep and to identify differencesin its composition between sexes during the reproductive and sexual segregation periods.Design/methodology/approach: The study was carried in the UMA Rancho NocheBuena, Hermosillo, Sonora. The microhistological technique and a cell catalog of plantsfrom the study area were used to identify plant species present in fecal samples ofbighorn sheep. The relative frequency, the Shannon-Weaver diversity index and theKulczynski similarity index were determined by sex and period (reproductive andsegregation)Results: The diet of bighorn sheep included 40 species, being herbaceous (36.1 ±4.4%) and grasses (26.8 ±8.9 %) the most common. The diet of males during thesegregation period was mainly composed of grasses (36.2%) and female diet byherbaceous (30%) and grasses (29.8%). No differences were found in the diversity ofthe diet of males and females in the segregation period (H &#39;= 1.0) and in general, their diets were very similar (80%).Limitations/implications: To collect a greater number of fecal samples by sex andperiod (reproductive and segregation) and to analyze the nutritional content of plantsconsumed by bighorn sheep.Findings/conclusions: In this study, the sexual segregation exhibited by the bighornsheep in the Wildlife Management and Conservation Unit Rancho Noche Buena was notdue to food preferences.

No abstract