Increasing drought pressure under anthropogenic climate change may jeopardize the potential of tropical forests to capture carbon in woody biomass and act as a long-term carbon dioxide sink. To evaluate this risk, we assessed drought impacts in 483 tree-ring chronologies from across the tropics and found an overall modest stem growth decline (2.5% with a 95% confidence interval of 2.2 to 2.7%) during the 10% driest years since 1930. Stem growth declines exceeded 10% in 25% of cases and were larger at hotter and drier sites and for gymnosperms compared with angiosperms. Growth declines generally did not outlast drought years and were partially mitigated by growth stimulation in wet years. Thus, pantropical forest carbon sequestration through stem growth has hitherto shown drought resilience that may, however, diminish under future climate change.

Little is known about the status of Puma concolor populations in Central and South America. Due to this reason, the present study contributes to the knowledge on puma populations providing information on abundance and density in Sierra Nanchititla, Mexico, as well as comparing recorded values against those obtained from zones of high and low concentration of camera traps. The sampling was carried out during a period of 30 months, which were divided into 3-month independent blocks. For the 8 first blocks, ten camera traps were set in an area where the separation among cameras was 1.6 km, and in the 2 last blocks 17 camera traps were set in an area where the separation was 4.6 km. The abundance was estimated between 2 and 5 individuals for the area with the highest concentration of cameras, lower than the abundance obtained in the area with the lowest concentration of cameras, i.e., 6 individuals. The density of the area with the highest camera concentration had a variation between 2.74 and 6.86 individuals/100 km2 in an effective survey area of 72.8 km2 and for the area of lowest concentration it was 1.21 individual/100 km2 in an effective survey area of 492.6 km2.

The study of predator–prey interactions is commonly analyzed using functional responses to gain an understanding of predation patterns and the impact they have on prey populations. Despite this, little is known about predator–prey systems with multiple prey species in sites near the equator. Here we studied the functional response of cougars (Puma concolor) in relation to their main prey, armadillo (Dasypus novemcinctus), coati (Nasua narica) and white‐tailed deer (Odocoileus virginianus). Between 2004 and 2010, cougar scats were collected along 5 transects to estimate the consumption of different prey species. A relative abundance index (RAI) was calculated for each prey species and cougar using 18 camera traps. We compared Holling type I, II and III functional response models to determine patterns in prey consumption based on the relative abundance and biomass of each prey species consumed. The 3 main prey species comprised 55% (armadillo), 17% (coati) and 8% (white‐tailed deer) of the diet. Type I and II functional responses described consumption of the 2 most common prey species armadillos and coati similarly well, while a type I response best characterized consumption of white‐tailed deer. A negative correlation between the proportions of armadillo versus coati and white‐tailed deer biomass in cougar scats suggests switching to consume alternative prey, confirming high foraging plasticity of this carnivore. This work represents one of the few studies to compare functional responses across multiple prey species, combined with evidence for prey‐switching at low densities of preferred prey.

Interspecific interactions among tropical mesocarnivorous species and other mammalian trophic guilds have been poorly studied, despite they have important implications in the survival, structure, demography, and distribution of these species. In this study we analyzed spatio-temporal interactions of three sympatric mesocarnivores that are located in the Northeastern limit of their geographic distribution in Mexico, with the objective of analyzing if these species coexist or compete in the axis of the temporal and spatial niche. With a sampling period from January 2015 to December 2016 and 26 camera-trapping stations (with in a set of two camera traps opposite to each other) and located along roads and animal trails, we determined the activity pattern and habitat use of L. wiedii (margay), L. pardalis (ocelote) y P. yagouaroundi (yaguarundi). All independent photographs of each species were grouped into three temporal categories (day, night and twilight) and six habitat categories; Oak Forest, Oak-Pine Forest, Cloud Forest, Pine-Oak Forest, Tropical Deciduous Forest and Medium Forest. Temporal and spatial overlap between species (i.e interactions) was obtained with the Czekanowski index and the Pianka index, respectively. These indices are symmetrical and take values from zero to one, where the results close to zero indicate that there is no overlap between species and values close to one indicate overlap. We obtained a total of 379 independent photographs, of which 239 corresponded to margay, 118 to ocelot and 22 to yaguarundi. Margay and ocelot were nocturnal, with 75 % of their records in this category showing a high temporal overlap (0.85); whereas yaguarundi was fully diurnal, suggesting it may be able to coexist with the other two species (margay and ocelot). Moreover, the yaguarundi used habitat similar to ocelot and margay (with high spatial overlap of 0.81 and 0.72, respectively), while the spatial overlap between the margay and ocelot was intermediate (0.53), since they used in most cases different habitat types. Our results suggest that there is no interspecific competition among these tropical mesocarnivorous species, probably due to antagonistic interactions among them on the temporal and spatial axis. These strategies may positively favor populations of mesocarnivores, which are characterized by having a high territorial behavior.

La distribución potencial del gran grisón, Galictis vittata, llega al centro y este de México, incluida la parte sur del estado de Tamaulipas. Sin embargo, no hay registros geográficos que confirmen este límite. El presente estudio documenta el primer registro del gran grisón fotografiado por trampas cámara en la Reserva de la Biosfera “El Cielo”, Tamaulipas, México. En el área de estudio se instalaron 26 trampas cámara que fueron programadas para obtener fotografías con la hora y fecha impresa. También se realizó un mapa en el que se integró la distribución potencial del grisón, los registros de ocurrencia publicados y los registros fotográficos de “El Cielo”. Una trampa cámara registró dos fotografías del gran grisón en la Reserva de la Biosfera “El Cielo”, dentro de un bosque de pino-encino conservado. Los dos registros representan el único avistamiento confirmado para el grisón en Tamaulipas, y están localizados a 64.4 km al noroeste de la distribución potencial estimada y a 186 km al norte del registro confirmado en el sur del estado de San Luis Potosí. Los registros de este estudio expanden tanto la distribución potencial como la distribución conocida del grisón hacia el noroeste y al norte, respectivamente, y también, aumentan el límite de elevación conocido en México de 1,500 a 1,790 m. La presencia del gran grisón en “El Cielo”, se debe probablemente a que este sitio tiene las condiciones de hábitat para que se pueda distribuir esta especie.