Time filter

Source Type

Poindexter C.J.,University of Oklahoma | Schnell G.D.,University of Oklahoma | Sanchez-Hernandez C.,National Autonomous University of Mexico | Romero-Almaraz M.D.L.,Escuinapa No. 92 bis. Col. Pedregal de Santo Domingo | And 4 more authors.
Mammalian Biology | Year: 2012

Use of habitat is a critical component related to structure of small-mammal communities, with partitioning occurring primarily along dimensions of microhabitat, although use of microhabitat often does not explain fully use at a macrohabitat level. Through grid studies of small mammals in coastal Colima, Mexico (during January 2003-2005), we appraised influence of available habitat, species richness, abundance, and cumulative abundance of other small mammals on variation in habitat used by species. We evaluated 14 habitat variables (reflecting ground cover, slope, canopy, and vegetation density on vertical and horizontal axes) and developed a composite variable (principal component 1) reflecting general openness of habitat through which we addressed habitat use. For the four most common mammalian species (. Sigmodon mascotensis, . Heteromys pictus, . Baiomys musculus, and . Oryzomys couesi), two measures of variation in habitat used were employed to estimate niche breadth, one of which assessed variation in habitat use relative to variation present on a grid. . Sigmodon mascotensis and . B. musculus preferred areas that were more open, and . H. pictus and . O. couesi occupied less-open areas; breadth of habitat use did not differ interspecifically. Habitat use was more variable on grids with more variability in habitat, although not greater than chance expectations. Findings do not lend support to the resource-breadth hypothesis as an explanation for population densities of species at a local level or the habitat-heterogeneity hypothesis as a predictor of species richness. Variation in habitat used by . S. mascotensis did not proportionally increase when diverse habitat was available but was greater when the species was more abundant. For . H. pictus, when cumulative abundance of other small mammals was greater, breadth of habitat used was greater. Intraspecific density-dependent habitat selection may result in . S. mascotensis selecting a greater variety of habitats, while greater interspecific abundance is related to a greater range in use of habitats by . H. pictus. . Baiomys musculus used a higher proportion of habitat relative to that available when more species were present on a grid. Variation in habitat used by . O. couesi was unrelated to any factor examined. Overall, the four species responded in notably different ways with respect to availability of habitat, abundance, and presence of other species. © 2012 Deutsche Gesellschaft für Säugetierkunde. Source

Schnell G.D.,University of Oklahoma | De Lourdes Romero-Almaraz M.,Escuinapa No. 92 bis. Col. Pedregal de Santo Domingo | Martinez-Chapital S.T.,National Autonomous University of Mexico | Sanchez-Hernandez C.,National Autonomous University of Mexico | And 4 more authors.
Mammalia | Year: 2010

In tropical deciduous forest along the Pacific coast in Colima, Mexico, we conducted eight-night mark-recapture studies of Sigmodon mascotensis (January 2003-2005), evaluating habitat preferences and demography. Yearly we established five grids with 100 trapping stations (one ground and one elevated trap; 24,000 trap-nights), each evaluated for 14 environmental measures. We captured 96 S. mascotensis 274 times on 10 grids, most at ground level (85.6%), with densities of 0.84-25.31 individuals/ha. Adults predominated (88.2%), sex ratio (males:females) was 1:0.74, and males were heavier. Sigmodon mascotensis co-occurred with Oryzomys couesi and Baiomys musculus more often and Heteromys pictus less often than chance expectation. For 2004, univariate analyses indicated that stations frequented had more ground cover in woody plants, forbs and grasses; less in litter and bare ground; more vegetation low and less high; lower and more open canopy; and longer distance to nearest tree. Logistic regression indicated preference for open canopy, dense low vegetation, little litter and longer distance to nearest tree. Nonparametric multiplicative regression showed occurrence likelihood decreased as litter increased and increased with increasing slope, average hits at 1 m and average distance to nearest tree. The likelihood was high with no or low canopy, as well as high canopy. © 2010 by Walter de Gruyter - Berlin - New York. Source

Almazan-Catalan J.A.,National Autonomous University of Mexico | Sanchez-Hernandez C.,National Autonomous University of Mexico | Ruiz-Gutierrez F.,Autonomous University of the State of Hidalgo | Romero-Almaraz M.D.L.,Escuinapa No. 92 bis. Col. Pedregal de Santo Domingo | And 3 more authors.
Revista Mexicana de Biodiversidad | Year: 2013

Information on distribution, habitat and measurements of the 6 species of cats found in Mexico and in Guerrero is provided. The specimens were recorded through direct and indirect methods. Lynx rufus is represented by the skin and skull of a young specimen and it is the second record for the state, while Puma concolor, Puma yagouaroundi, Leopardus pardalis, Leopardus wiedii and Panthera onca increase its distribution range in the state. The main threats to cats are habitat fragmentation and poaching. Source

Discover hidden collaborations