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The tropical dry forest is one of the most endangered ecosystems in the world, mainly due to deforestation and fragmentation. In Mexico more than half of its surface has disappeared, affecting biodiversity. The objective of this study was to compare the richness, diversity, and relative abundance of medium and large mammals in two sites with different management and conservation status, and where tropical dry forest is present. We also sought to find out which variables of habitat and human influence are related to the presence of the most common species. The study sites were in Pastorias, Actopan, Veracruz and San Juan Bautista Cuicatlan, Oaxaca, Mexico. The first site is highly transformed by anthropogenic activities, while the second is within the protected natural area of the Tehuacan-Cuicatlan Biosphere Reserve (TCBR). In Pastorias 11 camera-traps were set up from september 2015 to september 2016; while in Cuicatlan 10 camera traps were set up from october 2013 to july 2014. The sampling effort was 3526 days/trap which yielded 443 independent records for the first site, and 2690 days/trap that yielded 378 independent records for the second site. In each locality 13 species of mammals were recorded. In particular, three of these species are endangered (Tamandua mexicana, Leopardus wiedii, and Lynx rufus) and two are under threat (Herpailurus yagouaroundi and Galictis vittata). The true diversity of medium and large mammals between communities was different. According to the relative abundance index (RAI) the most abundant species are Odocoileus virginianus, Urocyon cinereoargenteus and Canis latrans. Regression analyses suggest that the variables of season, the cover of secondary vegetation and distance to the nearest human locality are related to the record of these species. Despite the anthropogenic pressure in Pastorias, tropical dry forest remnants still maintain high species richness, which is very similar to that of a site as preserved as Cuicatlan. However, the low RAIs value of several mammals may indicate that habitat quality could not maintain large population numbers. Therefore, it is necessary to develop programs to conserve this ecosystem.

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ResumenEl empleo de cámaras trampa es un método que se ha popularizado en la última década debido al desarrollo tecnológico que ha hecho más accesible la adquisición de este equipo. Una de las ventajas de este método es que podemos obtener mucha información en poco tiempo de diferentes especies. Sin embargo, existen pocos programas que faciliten la organización y extracción de la información de una gran cantidad de imágenes. Recientemente se ha puesto disponible libremente el paquete R llamado camtrapR, el cual sirve para extraer los metadatos de las imágenes, crear tablas de registros independientes, registros de presencia/ausencia para ocupación, y gráficos espaciales. Para comprobar la funcionalidad del programa en este artículo presentamos seis ejemplos de las principales funciones de camtrapR. Para esto se utilizó un conjunto de imágenes obtenidas con 10 cámaras-trampa en una localidad de la Reserva de la Biosfera Tehuacán-Cuicatlán. camtrapR se aplicó para probar los siguientes objetivos: organización y manejo de las fotos, clasificación por especie, identificación individual, extracción de metadatos por especie y/o individuos, exploración y visualización de datos, y exportación de datos para análisis de ocupación. Está disponible libre el código R utilizado en este trabajo. De acuerdo a los resultados obtenidos se considera que camtrapR es un paquete eficiente para facilitar y reducir el tiempo de extracción de los metadatos de las imágenes; así mismo es posible obtener los registros independientes sin errores de omisión o duplicación de datos. Además, permite crear archivos *.csv que después pueden ser analizados con otros paquetes R o programas para otros propósitos.Palabras clave: base de datos, historias de captura, metadatos, R. AbstractThe camera-trap is a method that has become popular in the last decade due to the technological development that has made the acquisition of this equipment more accessible. One of the advantages of this method is that we can get a lot of information in a short time for different species. However, there are few programs that facilitate the organization and extraction of information from large number of images. Recently, the R package called camtrapR has been made freely available, which serves to extract the metadata from the images, create independent record tables, occupation presence/absence registers and spatial graphics. To check the functionality of this package, in this article we present six examples of how to use the main functions of camtrapR. For this purpose, we used a data set of images obtained with 10 cameras in the location of the Tehuacán-Cuicatlán Biosphere Reserve. camtrapR was applied to test the following objectives: organization and management of the photos, classification by species, individual identification, extraction of metadata by species and individuals, exploration and visualization of data, and export of data for analysis of occupation. The R code used in this work is available freely in line. According to our results, camtrapR is an efficient package to facilitate and reduce the extraction time of the metadata of the images; it is also possible to obtain the independent records without errors of omission or duplication of data. In addition, it allows to create * .csv files that can then be analyzed with other R packages or programs for different objectives.Key words: capture histories, database, metadata, organization, R.

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