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San Miguel de Cozumel, Mexico

McFadden K.W.,Columbia University | Garcia-Vasco D.,Institute Ecologia | Cuaron A.D.,SACBE Servicios Ambientales | Valenzuela-Galvan D.,Autonomous University of the State of Morelos | And 2 more authors.
Biodiversity and Conservation

Insular carnivores represent some of the most critically threatened species, but also the least known. To evaluate the conservation status of these species, thorough abundance estimates are urgently required. To better understand the population biology and conservation status of the endemic and threatened pygmy raccoon (Procyon pygmaeus) and dwarf coati (Nasua nelsoni) on Cozumel Island, Mexico, we worked island-wide to identify the presence of these species, and for the pygmy raccoon we studied several populations in depth during 2001-2003. On Cozumel, trapping was conducted for >6,600 trap nights in 19 locations of varying habitat types. A total of 96 pygmy raccoons (47 males and 49 females) and a single adult, male dwarf coati (N. nelsoni) were captured. Estimated total annual pygmy raccoon population size ± SE was 80 ± 26.1, resulting in an average density of 22 ± 5.1 raccoons/km2 for the three small sites where the animals persist. Based in part on the findings of this study that indicate these species have a restricted range and small population numbers, the IUCN recently changed the listing of the pygmy raccoon to Critically Endangered from Endangered. In contrast, the status of the dwarf coati (Endangered) has not been changed, although the taxon is in eminent danger of extinction and in need of immediate conservation action. © Springer Science+Business Media B.V. 2009. Source

Vazquez-Dominguez E.,National Autonomous University of Mexico | Mendoza-Martinez A.,National Autonomous University of Mexico | Orozco-Lugo L.,Autonomous University of the State of Morelos | Cuaron A.D.,SACBE Servicios Ambientales
Acta Chiropterologica

Islands and insular biotas have been recognized as ideal models for studying adaptive radiations and evolutionary processes. In the present study we investigated the Jamaican fruit-eating bat, Artibeus jamaicensis from Cozumel Island, to evaluate the effect of ecological features on genetic diversity and structure across three different environments, semi-evergreen tropical forest, mangrove, and cenotes, using six microsatellite loci in 105 individuals. Genetic diversity was relatively high (forest HO = 0.693, HNei = 0.825; mangrove HO = 0.702, HNei = 0.710; cenotes HO = 0.695, HNei = 0.847). Pairwise genetic differentiation measures between localities were not significant and the overall level of differentiation was markedly low (FST = 0.009, G'ST = 0.088). Likewise, results showed that A. jamaicensis consists of one genetic group and relatedness among individuals was low. Results are concordant with our predictions that the island population will show high genetic diversity and null structure at the fine spatial scale examined. We conclude that ecological features like dispersal and generalist habits are the factors influencing population structure and genetic diversity of A. jamaicensis on the island, and that factors like the species polygynous mating system, female philopatry and male differential dispersal do not prevail in the island population. Cozumel Island is facing severe conservation problems, mainly from habitat perturbation, urbanization and introduction of exotic species, hence the present genetic information is of great value as a basis for future research and protection of the species. © Museum and Institute of Zoology PAS. Source

Aguilar-Melo A.R.,National Autonomous University of Mexico | Andresen E.,National Autonomous University of Mexico | Cristobal-Azkarate J.,University of Cambridge | Arroyo-Rodriguez V.,National Autonomous University of Mexico | And 5 more authors.
American Journal of Primatology

Animals' responses to potentially threatening factors can provide important information for their conservation. Group size and human presence are potentially threatening factors to primates inhabiting small reserves used for recreation. We tested these hypotheses by evaluating behavioral and physiological responses in two groups of mantled howler monkeys (Alouatta palliata mexicana) at the "Centro Ecológico y Recreativo El Zapotal", a recreational forest reserve and zoo located in the Mexican state of Chiapas. Both groups presented fission-fusion dynamics, splitting into foraging subgroups which varied in size among, but not within days. Neither subgroup size nor number of people had an effect on fecal cortisol. Out of 16 behavioral response variables tested, the studied factors had effects on six: four were affected by subgroup size and two were affected by number of people. With increasing subgroup size, monkeys increased daily path lengths, rested less, increased foraging effort, and used more plant individuals for feeding. As the number of people increased, monkeys spent more time in lower-quality habitat, and less time engaged in social interactions. Although fecal cortisol levels were not affected by the factors studied, one of the monkey groups had almost twice the level of cortisol compared to the other group. The group with higher cortisol levels also spent significantly more time in the lower-quality habitat, compared to the other group. Our results suggest that particular behavioral adjustments might allow howler monkeys at El Zapotal to avoid physiological stress due to subgroup size and number of people. However, the fact that one of the monkey groups is showing increased cortisol levels may be interpreted as a warning sign, indicating that an adjustment threshold is being reached, at least for part of the howler monkey population in this forest fragment. © 2013 Wiley Periodicals, Inc. Source

Vazquez-Dominguez E.,National Autonomous University of Mexico | Suarez-Atilano M.,National Autonomous University of Mexico | Booth W.,North Carolina State University | Gonzalez-Baca C.,SACBE Servicios Ambientales | Cuaron A.D.,SACBE Servicios Ambientales
Biological Invasions

Only one study has described the population genetic structure of Boa constrictor imperator and only in a single naturally colonized island. B. c. imperator, a snake with a naturally wide distribution across the Neotropics, was introduced to Cozumel Island, Mexico, in 1971. At present, it is one of the most abundant, widely distributed, terrestrial vertebrate on the island. We analysed the genetic diversity and structure, based on seven microsatellite loci, of 76 individuals of B. c. imperator from Cozumel. We also included 96 samples from different localities across mainland Mexico, to review the potential origin of the founder individuals. We identified two genetically differentiated populations on Cozumel that showed moderate levels of genetic diversity (H o = 0. 590-0. 620), with a low but significant level of genetic structure (F ST = 0. 032). Individuals were highly unrelated (71 %) and the majority of genetic variation was distributed within individuals (84 %). We detected a signal of reduction in population size and evidence of genetic bottleneck. The genetically closest mainland populations, indicating potential source of island founders, are localities from the Gulf of Mexico and Yucatan peninsula. Results are in agreement with a recently introduced population, founded by a few individuals originating from several sources, which has been successful. B. c. imperator is jeopardizing a highly vulnerable insular ecosystem, hence its eradication from Cozumel is urgently needed. Our information is also valuable for other introduced-boa cases or as a basis for its conservation elsewhere given its classification as a threatened species. © 2012 Springer Science+Business Media B.V. Source

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