Octavio Monroy-Vilchis

Cougar and jaguar habitat use and activity patterns in central Mexico

In this study the habitat use and activity patterns of the two of the largest cats of the Americas in central Mexico were studied. Three ways to detect felid presence were employed from August 2002 to May 2006: interviews, signs, and camera-traps. 478 records were obtained, from which 441 were from cougar and 37 from jaguar. These records included positive response in 118 of 140 interviews and 236 records of signs (mainly tracks and scats), and 124 photographs. Both felids preferred pine-oak forest habitats, with altitudes higher than 1800 m, distances between 3509 and 4377 m from roads, between 2329 and 4650 m from settlements, and distances to very steep slopes between 1048 and 2059 m, for jaguar, and for cougar lower than 1047 m. Jaguar activity was recorded mainly during nighttimes, between 0:00 and 6:00, whereas cougar was active between 4:00 and 6:00 and between 18:00 and 22:00 hours, avoiding the jaguars principal activity period.

Jaguar (Panthera onca) in the State of Mexico

Abstract We document the jaguar (Panthera onca) in the Sierra Nanchititla (state of Mexico) in pine-oak forest. During October 2002–December 2004, we determined presence of jaguars using three methods: we conducted interviews in local communities, collected scats, and installed automated-camera detection systems. Although no jaguar was mentioned in 86 interviews, three photographs of a male were obtained, and 10 of 132 scats were attributed to P. onca. This represents the first record of P. onca in central Mexico within the Balsas River macro-basin.

Variation of abundance and density of Puma concolor in zones of high and low concentration of camera traps in Central Mexico

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.

Is food quality important for carnivores? The case of Puma concolor

The composition and energetic content of puma (Puma concolor) diet in Sierra Nanchititla Natural Reserve (SNNR), Mexico, were determined. We collected 183 scats, where 27 components were identified by occurrence (88.07% mammals). The pumas diet was mainly composed of armadillo (Dasypus novemcinctus, 40.33%), white-nosed coati (Nasua narica, 11.93%) and white-tailed deer (Odocoileus virginianus, 6.17%). Energetic analysis of prey indicates that the puma prefers those with higher energetic content (kcal/kg). The prey with the most energetic contribution is armadillo (2398.70 kcal/kg), followed by white-nosed coati (2225.25 kcal/kg) and finally white-tailed deer (2165.52 kcal/kg). The differences in energetic content between prey species were statistically significant. The number of individuals killed/year on average to support a puma was 51 armadillos, 16 white-tailed deer and 7 white-nosed coatis. The results indicate a greater consumption of prey that provide more kilocalories to the predator, and suggests the importance of quality meat in the diet of pumas.

Feeding ecology of puma Puma concolor in Mexican montane forests with comments about jaguar Panthera onca

We analyse the diet and prey selection of puma Puma concolor and describe opportunistically the diet of jaguar Panthera onca in montane forest in the Sierra Nanchititla Natural Park, central Mexico. We analysed prey selection in relation to energy content and population abundance, inferred through camera trapping. Analysis of 209 puma scats showed that their main prey was nine-banded armadillo Dasypus novemcinctus followed by white-nosed coati Nasua narica and white-tailed deer Odocoileus virginianus. Pumas did not take prey in proportion to their relative abundance, but selected energetically profitable prey such as nine-banded armadillo, which formed the bulk of their diet. In 13 scats of jaguar, nine-banded armadillo was also the most important prey followed by domestic goat Capra hircus. We discuss the implications for management of predators and prey.

Genetic diversity and genetic structure of an endemic Mexican Dusky Rattlesnake (Crotalus triseriatus) in a highly modified agricultural landscape: implications for conservation

Abstract It is necessary to determine genetic diversity of fragmented populations in highly modified landscapes to understand how populations respond to land-use change. This information will help guide future conservation and management strategies. We conducted a population genetic study on an endemic Mexican Dusky Rattlesnake (Crotalus triseriatus) in a highly modified landscape near the Toluca metropolitan area, in order to provide crucial information for the conservation of this species. There was medium levels of genetic diversity, with a few alleles and genotypes. We identified three genetically differentiated clusters, likely as a result of different habitat cover type. We also found evidence of an ancestral genetic bottleneck and medium values of effective population size. Inbreeding coefficients were low and there was a moderate gene flow. Our results can be used as a basis for future research and C. triseriatus conservation efforts, particularly considering that the Trans-Mexican Volcanic Belt is heavily impacted by destructive land-use practices.

Microhabitat Types Promote the Genetic Structure of a Micro-Endemic and Critically Endangered Mole Salamander (Ambystoma leorae) of Central Mexico

The reduced immigration and emigration rates resulting from the lack of landscape connectivity of patches and the hospitality of the intervening matrix could favor the loss of alleles through genetic drift and an increased chance of inbreeding. In order for isolated populations to maintain sufficient levels of genetic diversity and adapt to environmental changes, one important conservation goal must be to preserve or reestablish connectivity among patches in a fragmented landscape. We studied the last known population of Ambystoma leorae, an endemic and critically threatened species. The aims of this study were: (1) to assess the demographic parameters of A. leorae and to distinguish and characterize the microhabitats in the river, (2) to determine the number of existing genetic groups or demes of A. leorae and to describe possible relationships between microhabitats types and demes, (3) to determine gene flow between demes, and (4) to search for geographic locations of genetic discontinuities that limit gene flow between demes. We found three types of microhabitats and three genetically differentiated subpopulations with a significant level of genetic structure. In addition, we found slight genetic barriers. Our results suggest that mole salamander’s species are very sensitive to microhabitat features and relatively narrow obstacles in their path. The estimates of bidirectional gene flow are consistent with the pattern of a stepping stone model between demes, where migration occurs between adjacent demes, but there is low gene flow between distant demes. We can also conclude that there is a positive correlation between microhabitats and genetic structure in this population.

Feeding Interactions in an Assemblage of Terrestrial Carnivores in Central Mexico

BackgroundWe evaluated the strategies of resources partitioning among species, dietary overlap and niche breadth in an assemblage of carnivores integrated by top predators (Puma concolor and Panthera onca) and mesopredators (Leopardus pardalis, Leopardus wiedii, Puma yagouaroundi, Nasua narica and Urocyon cinereoargenteus). The aim of this study was to investigate the mechanisms explaining the coexistence among species at a temperate zone in central Mexico.ResultsWe collected 259 scats of carnivores and identified 45 food items. The analysis showed the common consumption of mammals in the assemblage, and the correspondence analysis showed three guilds: 1) top predators associated with the use of medium-sized mammals and the exclusive consumption of large mammals, 2) carnivore mesopredators associated with the consumption of small mammals and birds and 3) omnivore mesopredators associated with the consumption of arthropods and plants. The dietary overlap analysis indicated a low overlap between guilds and a high overlap within them. Top predators were specialist foragers, whilst the carnivore mesopredators showed generalist consumption.ConclusionsThe coexistence in this carnivore assemblage seems to be related to body size, morphology and prey segregation because such characteristics suggest the presence of three guilds. We observed high dietary overlap within guilds and resource partitioning between guilds.

DEJECTION AND EXPULSION RATES OF COYOTES (CANIS LATRANS) IN CAPTIVITY

Abstract We obtained dejection and expulsion rates for use as correction factors in studies of diet and relative abundance of coyotes (Canis latrans). Feeding tests were performed at the Zacango Zoo, Calimaya, Mexico. We tested 3 treatments with different categories of biomass (10 to 80 g, 100 to 700 g, and 1,000 to 4,500 g). Dejection rates averaged 0.79 ± 0.22 SD excrements/g of biomass, with no significant difference among treatments. Expulsion rates significantly differed, with 1.33 scats produced/g of biomass for the first category (10 to 80 g), 4.69 scats/g of biomass for the second category, and 6.91 scats/g of biomass for the third. We compared these values with those from other studies performed with wolf (Canis lupus) and lynx (Lynx pardinus).

Monitoring population density and activity pattern of white-tailed deer (Odocoileus virginianus) in Central Mexico, using camera trapping

Abstract White-tailed deer (Odocoileus virginianus) are economically important in the Americas and are also the main prey of predators such as the jaguar (Panthera onca) and puma (Puma concolor), but human influence has led to the decline of their populations by hunting and increasing agricultural and pastoral land use. On the other hand, there is a lack of ecological knowledge on the species in central Mexico. We investigated the population density and activity pattern of white-tailed deer in the Sierra Nanchititla, Mexico, using 10 camera traps. Sampling was conducted over 18 months between 2004 and 2007. We identified deer in photographs, and the population abundance was estimated using the CAPTURE program and density by dividing the estimated abundance by the effective sampled area. The daily activity pattern was derived by using the recorded time in the photographs for each hour of the day. Population density was from 2.0 to 6.3 in the wet season and 0.8–12 individuals/km2 in the dry, showing a diurnal pattern. This study was one of the first using camera traps in Mexico, for a sampling period longer than 1 year and provided information for the development of management programs.