Miguel Briones-Salas

Bat and Rodent Diversity in a Fragmented Landscape on the Isthmus of Tehuantepec, Oaxaca, Mexico

We assessed the patterns of diversity, richness, abundance, and dissimilarity in rodent and bat communities for four sites on the Isthmus of Tehuantepec in Oaxaca, Mexico, an important region given the enormous number of endemic Neotropical species. The main objective was to examine rodent and bat community parameters relative to habitat diversity and human habitat disturbance in a fragmented landscape. We captured 1,133 individuals of 13 rodent species and 26 bat species from January to August 2006. The site (landscape unit) with greatest habitat diversity also had the highest diversity of rodents. Species dissimilarity was low between sites that had similar degrees of human disturbance. For rodents, species dissimilarity between habitats on the Isthmus of Tehuantepec landscape was generally high; therefore, the species are not distributed evenly across the entire landscape. For bats, the degree of species dissimilarity between the different habitats of the landscape was low. The distribution of bat species across the landscape is a reflection of their high vagility and the spatial structure of the landscape. The results show the importance of a diversity of habitats to the patterns of richness, abundance, and dissimilarity of mammals in the study area.

Deforestation Thresholds for Phyllostomid Bat Populations in Tropical Landscapes in the Huasteca Region, Mexico

The loss and degradation of forests in tropical regions have modified tree cover, creating deforested landscapes. It has been suggested that there are thresholds in these landscapes beyond which the diversity, distribution, abundance, and fitness of different biological groups can be affected. In this study, the ecological habitat thresholds were detected for eight populations of phyllostomid bats along an environmental gradient of forest loss in the Huasteca region, Mexico. At a local scale, we analyzed canopy loss, and we also detected these thresholds at the landscape level, as a function of forest remnant area at three scales with radii of 1, 3 and 5 km. The data were analyzed using the Threshold Indicator Taxa ANalysis (TITAN) method for detecting indicator species along gradients. The bats exhibited three different types of response to habitat loss: 1) Leptonycteris yerbabuenae, Chiroderma salvini, Sturnira hondurensis, and Artibeus lituratus were more abundant where canopy cover was present at the local site, even though the landscape had been deforested; 2) Sturnira parvidens and Artibeus jamaicensis required tree cover at all spatial scales; and 3) Glossophaga soricina and Desmodus rotundus are species that might be locally abundant in habitats with little canopy, but both species need landscapes that have not been deforested. In conclusion, these populations of phyllostomid bats were sensitive to deforestation in different ways, their response to the habitat loss gradient varying among species and with spatial scale.

NOTEWORTHY RECORDS OF TWO RARE MAMMALS IN SIERRA NORTE DE OAXACA, MEXICO

Abstract We made an intensive survey of small mammals in the Sierra Norte de Oaxaca region, in Oaxaca, México. We recorded the presence of 2 interesting species: water mouse (Rheomys mexicanus) and river otter (Lontra longicaudis annectens). The locality for the river otter represented the highest altitude recorded in México for this species. The locality for the water mouse is the fourth known in all of its range and the second record in Sierra Norte.

Representatividad de los tipos de vegetación en distintas iniciativas de conservación en Oaxaca, México

Oaxaca shows an exceptional biodiversity, although a high rate of natural habitat loss threatens its conservation. Here we analyze different initiatives for ...

Effects of a wind farm installation on the understory bat community of a highly biodiverse tropical region in Mexico

Wind energy has rapidly become an important alternative among renewable energies, and it is generally considered clean. However, little is known about its impact at the level of ecological communities, especially in biodiversity hotspots. The Isthmus of Tehuantepec is a highly biodiverse region in Mesoamerica, and has the highest potential for generating wind energy in Mexico. To assess the effects of installing a wind farm on the understory bat community in a landscape of fragmented habitat, we assessed its diversity and composition over four stages of installation (site preparation, construction, and two stages of operation). We captured 919 bats belonging to 22 species. Species richness, functional diversity and phylogenetic diversity decreased during construction and the first stage of operation. However, these components of biodiversity increased during the second stage of operation, and species composition began to resemble that of the site preparation stage. No species considered as sensitive to disturbance was recorded at any stage. This is the first study to reveal the diversity of a Neotropical bat community after wind turbines begin to operate.

Ecology and local knowledge of the Baird's tapir (Tapirella bairdii) in the Sierra Madre de Oaxaca, Mexico

As well as being of global cultural importance (from local tribal folklore to being an iconic species for conservation), the tapir plays an important role in its ecosystem as a herbivore and seed disperser. However, the ecology and ethnozoology of the endangered Bairds tapir in the north of Oaxaca, Mexico is poorly understood. We used camera traps to estimate its relative abundance and density and to describe the activity patterns of the northernmost population of Bairds tapir in the Sierra Madre de Oaxaca. Local knowledge concerning the tapir was also documented, along with the conservation strategies undertaken by the 2 indigenous communities that own the land where the study site is located. Only adult tapirs were photographed, and these were active 14 h per day, but were mainly nocturnal and crepuscular. The estimated relative abundance (12.99 ± 2.24 events/1000 camera days) and density values (0.07-0.24 individuals/km(2) ) were both similar to those found in another site in Mexico located within a protected area. Semi-structured interviews revealed that people have a basic understanding of the eating habits, activity and main predators of the tapir. There were reports of hunting, although not among those respondents who regularly consume bush meat. Thus, the relative abundance and density estimates of tapir at the study site could be related to the favorable condition of the forest and the absence of hunting and consumption of tapir meat. Fortunately, the local people are conducting initiatives promoting the conservation of this ungulate and its habitat that combine to constitute a regional trend of habitat and wildlife protection.

Mammals in tropical dry forest on the central coast of Oaxaca, Mexico

The tropical dry forests of Mexico are one of the world’s biodiversity hotspots. To contribute to the knowledge of mammal diversity and conservation of the central coast of Oaxaca State, southern Mexico, we conducted field surveys in the area. Additional information was obtained from literature and museum databases. In order to compare the taxonomic similitude between areas along the Planicie Costera del Pacifico province we performed a taxonomic similarity analysis using data from the literature and the present study. A total of 49 species of mammals belonging to 19 families and eight orders were recorded. The maximum number of species was recorded in deciduous forest ( n = 46), followed by semideciduous forest ( n = 11). The similarity index was low (<50%) between areas along the Planicie costera del Pacifico, indicating higher species turnover. The high mammal diversity, the presence of endemic (8%), threatened species (16%), and voluntary conservation areas highlight the importance of this region.

New Records of the Endemic Chinanteco Deermouse Habromys chinanteco (Rodentia: Cricetidae) in the Sierra Madre de Oaxaca, Mexico

Abstract During a study of rodents at Cerro Pelón, Oaxaca, Mexico, in the northwestern portion of the Sierra Madre de Oaxaca physiographic subprovince, we collected three Chinanteco deermice Habromys chinanteco. This microendemic rodent is rare in terms of habitat and population, and had not been collected in the wild since 1975. These records corroborate continuing presence of H. chinanteco in this region. Resumen Durante un estudio sobre roedores en la localidad de Cerro Pelón, ubicado en la parte noroeste de la subprovincia fisiográfica de la Sierra Madre de Oaxaca, México, colectamos tres individuos del pequeño ratón roedor arborícola Habromys chinanteco. Este roedor microendémico es raro en términos de hábitat y poblaciones, el cual no había sido colectado en campo desde 1975. Estos registros corroboran la continua presencia de H. chinanteco en esta región.