Dinámica poblacional de puma concolor y sus presas principales, en la sierra Nanchititla, México

Los estudios de dinámicas poblacionales y demográficas, son útiles en los ecosistemas, ya que ayudan a comprender el papel ecológico y la relación que desempeñan los carnívoros y sus presas dentro de una comunidad ecológica y ayudan a establecer estrategias para su conservación. En este estudio se estimó la abundancia, densidad y patrón de actividad de Puma concolor y para cada una de sus presas principales (armadillo, coatí y venado) y se determino la interacción depredador-presa. También se estimo la supervivencia, emigración e inmigración para puma. La zona de estudio fue la Reserva Natural Sierra Nanchititla, ubicada en la cuenca del Balsas en el centro de México. Se utilizaron trampas cámara para obtener registros fotográficos de puma y cada una de sus presas. La abundancia de puma se obtuvo con los programas MARK y CAPTURE, dando como resultado cuatro y ocho individuos, respectivamente y densidades de 2 a 6 individuos/100km2, el patrón de actividad para esta especie fue nocturna. La densidad de venado fue 2 a 6.3 individuos/km2 en las lluvias y de 0.8 a 12 en la sequia y con actividad principalmente diurna. Se obtuvo un índice de abundancia relativa para las otras presas, siendo el coatí el más abundante con un IAR de 1.23 a 10.95 y patrón de actividad diurno y armadillo de 0.16 a 1.19 con actividad nocturno. El puma mostró una respuesta funcional tipo III para su presa principal (armadillo), pero no para sus otras dos presas. Los modelos de regresión múltiple mostraron que la abundancia de armadillo y coatí tienen un efecto significativo del 98% sobre la tasas de crecimiento de puma, lo que permitió encontrar un efecto buttom-up en esta población. Los patrones de actividad mostraron que el puma sobrepone su actividad con el de armadillo, lo que muestra porque es la presa principal. La sobrevivencia de puma fue de 100 % en los diferentes muestreos analizados y la migración e inmigración de 57 % en la primer área de muestreo, 40% en la segunda área de muestreo y de 100% en la tercera. Finalmente con los resultados de este estudio se muestra que el armadillo es una especie importante para puma y que se requiere establecer estrategias de conservación, para que las poblaciones de puma puedan mantenerse viables a largo plazo en la RNSN

Top-down and bottom-up control on cougar and its prey in a central Mexican natural reserve

Top-down and bottom-up controls are hypothe sized to regulate population structures in many ecosystems. However, few studies have had the opportunity to analyzeboth processes in the natural environment, especially on largecarnivores like the cougar (Puma concolor). Previously, studies show that cougar diet in the Sierra Nanchititla NaturalReserve (SNNR), central Mexico, is mainly armadillo, coati, and white-tailed deer. We assess whether top-down and/or bottom-up control regulate this endangered food web: (a) wepredicted that seasonal per capita changes in abundance (pca) of cougar will be positively affected by the abundance of their main prey; (b) primary productivity in SNNR will affect the pca of prey species, driving bottom-up control; and (c) armadillo, coati, and white-tailed deer pca will be affected by the abundance of cougar, generating top-down control. Using 15 camera traps for 6 years in the SNNR, we calculated a relative abundance index (RAI) and pca for cougar and each of the focal prey, and we used the normalized difference vegetation index (NDVI) as a proxy of primary productivity. We constructed multiple regression models and selected the best linear models based on ranking the AICc values. Our analysis suggests that P. concolor pca is best explained by bottom-up control and intraspecific feedback. White-tailed deer and armadillo pca were both significantly affected by cougar abundance, indicating top-down control for these prey species, but NDVI was not retained in any of the models selected for prey pca. Our results indicate that both bottom-up and top-down control are involved in regulating this endangered food web in the SNNR, Mexico

Functional responses of cougars (Puma concolor) in a multiple prey-species system

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 Sierra Nanchititla Natural Reserve (Mexico), 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 five 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 three 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 two 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

Hibernation refuge of Thamnophis scalaris Cope, 1861, in Central Mexico

The use of a refuge during the hibernal period of a snake species in central Mexico is describedThe genus Thamnophis FiTZiNGER, 1843 (garter snakes) includes the most low- temperature-tolerant snake species in North America. The northern species of this group are among the most studied and well known snakes; e.g., T. sirtalis (LiNNAEuS, 1758), selects specific traits of hibernation refuges and congregates in thousands as a strategy for hibernation (ROSSMAN et al. 1996). However, the hibernation process is scarcely known in southern populations.ideaWild Comisión Estatal de Parques Naturales y de la Fauna (CEPANAF

Parasites in feces of the endemic rattlesnake, Crotalus triseriatus (Serpentes: Viperidae), from Mexican highlands

Artículo científicoThere are few studies about parasitic infections in Crotalus triseriatus (Wagler, 1830), an endemic rattlesnake from the highlands of central Mexico. This species occupies several habitats, from conserved forested regions to heavily impacted landscapes. To increase the parasitological knowledge of this reptile species without impacting populations, we obtained fecal samples of 16 rattlesnakes between 2012 and 2014 from Toluca Valley, Mexico. By using flotation technique, we found oocysts of Eimeria sp. and eggs of Capillariidae sp. The most frequent parasite was Eimeria sp. (62.5%). This study provides the first records of occurrence of parasites in reptilian feces from Mexico. Our results may be important for wildlife conservation purposes, for example, they could indicate of the population health of this species during processes of translocation

Interacciones temporales y espaciales de mesocarnívoros simpátricos en una Reserva de la Biosfera: ¿coexistencia o competencia?

Abstract: Temporal and spatial interactions of sympatric mesocarnivores at a Biosphere Reserve: coexistence or competition? 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. Rev. Biol. Trop. 66(3): 996-1008. Epub 2018 September 01. Key words: “El Cielo” Biosphere Reserve; Tamaulipas; Mexico; tropical felines; interespecific interaction

Parasites in feces of the endemic rattlesnake, Crotalus triseriatus (Serpentes: Viperidae), from Mexican highlands

There are few studies about parasitic infections in Crotalus triseriatus (Wagler, 1830), an endemic rattlesnake from the highlands of central Mexico. This species occupies several habitats, from conserved forested regions to heavily impacted landscapes. To increase the parasitological knowledge of this reptile species without impacting populations, we obtained fecal samples of 16 rattlesnakes between 2012 and 2014 from Toluca Valley, Mexico. By using flotation technique, we found oocysts of Eimeria sp. and eggs of Capillariidae sp. The most frequent parasite was Eimeria sp. (62.5%). This study provides the first records of occurrence of parasites in reptilian feces from Mexico. Our results may be important for wildlife conservation purposes, for example, they could indicate of the population health of this species during processes of translocation

Temporal and spatial segregation of top predators (Felidae) in a Mexican tropical Biosphere Reserve

Jaguars, Panthera onca (Linnaeus, 1758), and pumas, Puma concolor (Linnaeus, 1771) are the largest felids in the neotropics. Both can overlap in niche axes (time, space and prey), and are therefore potentially competing species. Segregation mechanisms presented by a low overlap in one of these axes of niche can facilitate the coexistence. Our aim was to analyze jaguar and puma temporal and spatial overlap for understanding their segregation mechanisms. Between 2015 and 2017, twenty-six camera trap stations were located in five habitat types of El Cielo Biosphere Reserve (ECBR) in northeastern Mexico. Temporal activity was analyzed using circular statistics and time overlap analysis. Spatial overlap was calculated with the Pianka index and a selectivity habitat analysis. Our results showed that jaguars and pumas were nocturnal and that the temporal overlap was high (∆4 = 0.77). We found an intermediate spatial overlap (Pianka index = 0.61). Jaguars were more selective and preferred the deciduous forest. In comparison, pumas preferred oak-pine forest, but also used oak and deciduous forest. Our results indicate that spatial segregation best explains the coexistence of jaguars and pumas in our study area, probably due to both habitat diversity in the reserve and the generalist habits of the puma

Diversidad y abundancia de mamíferos del bosque mesófilo de montaña del noreste de México

The cloud forest (CF) is one of the ecosystems with a great variety of biodiversity, however, it is also one of the most reduced in territorial surface with fragmentation among its distribution, which increases the probability of human disturbances and biodiversity loss. Our objective was to estimate alpha diversity and relative abundance of medium and large mammals present in the CF of El Cielo biosphere reserve (ECBR), Tamaulipas, Mexico. The study was carried out from January 2018 to December 2020. In this period, 20 sampling stations with one camera-trap were placed. We used the Hill series numbers method to estimate mammalian diversity during the rainy and dry seasons, and rarefaction curves to compare diversity between seasons. We estimated abundance with the relative abundance index (RAI). A total of 18 species of mammals were identified, corresponding to six orders and 12 families. The best represented order was Carnivora. The richness was 16 and 18 species, for the rainy and dry seasons, respectively. However, there were no significant differences between seasons. The species with the highest relative abundance in the rainy season was Mazama temama and the lowest Odocoileus virginianus. In the dry season, Didelphis sp. showed the highest IAR, and the lowest O. virginianus. Five species in danger of extinction were registered and and one threatened. The number of species described shows that it is one of the sites with the greatest richness of medium and large mammals in CF of Mexico and high abundances of M. temama, Ursus americanus and Leopardus wiedii stand out. In addition, the presence of species such as Panthera onca and Puma concolor shows that this type of vegetation is in a good state of conservation.El bosque mesófilo de montaña (BMM) es uno de los ecosistemas vegetales con una gran diversidad biológica, sin embargo, también es uno de los más reducidos en superficie territorial y su distribución es fragmentada, lo que incrementa su probabilidad de sufrir perturbaciones humanas y pérdida de la biodiversidad. El objetivo de esta investigación fue estimar la diversidad alfa y la abundancia relativa de los mamíferos medianos y grandes presentes en el BMM de la reserva de la biosfera El Cielo (RBEC), Tamaulipas, México. El estudio se realizó de enero del 2018 a diciembre del 2020. En este periodo se colocaron 20 estaciones de muestreo con una cámara-trampa. Se estimó la diversidad de los mamíferos durante la temporada de lluvia y seca con los números de la serie Hill. La diversidad se comparó entre temporadas con las curvas de rarefacción y la abundancia se estimó con el índice de abundancia relativa (IAR) para cada especie. Se lograron identificar 18 especies de mamíferos y el orden mejor representado fue Carnivora. La riqueza fue de 16 y 18 especies, para la temporada de lluvia y seca, respectivamente. La especie con mayor abundancia relativa en la temporada de lluvia fue Mazama temama y la de menor Odocoileus virginianus. En la seca, Didelphis sp. fue la que presentó mayor IAR, y la menor fue O. virginianus. Se registraron cinco especies que se encuentran en peligro de extinción y una considerada como amenazada. El número de especies que se describen muestra que se trata de uno de los sitios con mayor riqueza de mamíferos medianos y grandes en BMM de México y destacan abundancias relativas altas de M. temama, Ursus americanus y Leopardus wiedii. A demás, la presencia de especies como Panthera onca y Puma concolor, muestran que este tipo de vegetación tiene un buen estado de conservación

Mammals’ camera-trapping in Sierra Nanchititla, Mexico: relative abundance and activity patterns

La conservación de las especies y su manejo adecuado dependen de la disponibilidad de información sobre sus poblaciones, por ello es importante estudiar aspectos como la abundancia y el patrón de actividad. En esta investigación se utilizaron trampas-cámara para obtener índices de abundancia relativa y establecer el patrón de actividad de los mamíferos medianos y grandes de la Sierra Nanchititla, México. El trabajo se llevó a cabo durante el periodo de diciembre de 2003 a mayo de 2006, con un esfuerzo total de 4 305 días-trampa. Se obtuvieron 897 fotografías de 19 especies, las más abundantes fueron: Nasua narica, Sylvilagus floridanus y Urocyon cinereoargenteus, de acuerdo con el índice de abundancia relativa (IAR, número de registros independientes/100 días trampa), coincidiendo con estudios basados en métodos indirectos. El patrón de actividad de las especies registradas mostraron que el 67% son de hábitos nocturnos. Algunas especies mostraron diferencias con los patrones mencionados por otros autores, las cuales se relacionan principalmente con la estacionalidad, la disponibilidad de recursos y el sexo de los individuos.Species conservation and their management depend on the availability of their population behavior and changes in time. This way, population studies include aspects such as species abundance and activity pattern, among others, with the advantage that nowadays new technologies can be applied, in addition to common methods. In this study, we used camera-traps to obtain the index of relative abundance and to establish activity pattern of medium and large mammals in Sierra Nanchititla, Mexico. The study was conducted from December 2003 to May 2006, with a total sampling effort of 4 305 trap-days. We obtained 897 photographs of 19 different species. Nasua narica, Sylvilagus floridanus and Urocyon cinereoargenteus were the most abundant, in agreement with the relative abundance index (RAI, number of independent records/100 trap-days), and according to previous studies with indirect methods in the area. The activity patterns of the species showed that 67% of them are nocturnal, except Odocoileus virginianus, Nasua narica and others. Some species showed differences with previously reported patterns, which are related with seasonality, resources availability, organism sex, principally. The applied method contributed with reliable data about relative abundance and activity patterns.Universidad Autónoma del Estado de México con los proyectos FE012/2006, FE09/2007, FE014/2007-2009; El CONACYT con el proyecto 101254 y el PROMEP con el proyecto 103.5/10/0942