Eduardo Mendoza | Universidad Michoacana de San Nicolás de Hidalgo (original) (raw)

Papers by Eduardo Mendoza

Tropical Conservation Science, 2015

Ecology, Jan 9, 2018

An ignored role of sartenejas to mitigate water shortage hazards for tropical forest vertebrates ... more An ignored role of sartenejas to mitigate water shortage hazards for tropical forest vertebrates Water availability is a key limiting resource for vertebrates (Hayward and Hayward 2012). Even in tropical ecosystems supporting lush vegetation, water exists in forms not easily exploited by the local fauna (Kr€ ugel and Richter 1995; Ferrari and Hil ario 2012). For example, tropical seasonal forests growing on karst landscapes in the Yucatan Peninsula of Mexico lack flowing rivers or extensive water bodies on the surface (Garc ıa-Gil et al. 2002). However, it supports an extremely rich and abundant terrestrial vertebrate fauna (Calm e et al. 2015; Reyna-Hurtado et al. 2015). The capacity of this fauna to withstand the harsh environmental conditions imposed by water scarcity, particularly during the dry season, has traditionally been associated with natural waterholes, locally known as "aguadas" (O'Farrill et al. 2014). These aguadas form when rainfall accumulates in topographic depressions under

Los tapires (Tapirus spp.) son mamíferos que tienen una ecología e historia evolutiva fascinante.... more Los tapires (Tapirus spp.) son mamíferos que tienen una ecología e historia evolutiva fascinante. con un peso que puede rebasar los 250 kg, los tapires son animales imponentes; sin embargo, en su medio na-tivo (selvas, humedales, bosque de montaña, pára-mos), son inofensivos y se alimentan exclusivamente de tallos, follaje, frutos, semillas y corteza de árbo-les. 1 tienen un cuerpo grueso con patas relativamen-te cortas y una cabeza parecida a la de un caballo que remata en una trompa larga y flexible que usan para alcanzar y manipular sus alimentos. 2 son hábiles nadadores y su presencia se asocia a la cercanía de cuerpos de agua dulce. 3 el origen del género Tapirus se remonta al mioce-no (ca. 20 millones de años) y parece haberse dado conjuntamente en eurasia y América. 4 sin embargo, fue en este último continente donde experimentó su mayor diversificación. 5 Los tapires son uno de los po-cos grupos de la megafauna (vertebrados de gran ta-lla) sobrevivientes al gran evento de ext...

RESUMEN Para evaluar el potencial que el impacto humano tiene para modificar la configuración del... more RESUMEN Para evaluar el potencial que el impacto humano tiene para modificar la configuración del paisaje en la porción mexicana del Corredor Biológico Mesoamericano (CBM-MX) elaboramos modelos espacialmente explícitos de cambio de la cobertura y uso del suelo (CCUS), utilizando el programa Dinamica EGO. Para la modelación utilizamos la cartografía de vegetación y uso de suelo de INEGI (1993, 2002 y 2007) y un conjunto de variables explicativas (p.ej., distancia a carreteras y poblados, elevación, presencia de áreas naturales protegidas, entre otras). Calibramos los modelos para el período 1993-2002, simulamos el CCUS para el año 2007, y lo comparamos con el mapa de INEGI del 2007. Encontramos que la cercanía a poblados y carreteras aumenta la probabilidad de deforestación en el CBM-Mx y que, en contraste, la presencia de áreas naturales protegidas la reduce. Posteriormente, modelamos los CCUS para el año 2030 bajo dos escenarios: 1) Tendencial: las tasas de deforestación del períod...

Ciencia y desarrollo

El tapir es uno de los últimos representantes de la megafauna I que existió en el continente amer... more El tapir es uno de los últimos representantes de la megafauna I que existió en el continente americano, la cual incluía animales como el mamut, el tigre dientes de sable, los megaterios II y los gliptodontes, III entre otros. Juntos formaban parte de un conjunto de animales comparable en diversidad y talla al que actualmente existe en los bosques y sabanas de África. Esta fantástica fauna fue reducida por una ola de extinciones a finales del Pleistoceno, IV cuya causa aún se debate, pero se considera asociada a los grandes cambios climáticos ocurridos durante esa época, así como al impacto de la cacería practicada por el Homo sapiens. 1

2 Uno de los problemas más interesantes, pero a la vez más desafiantes, de la conservación biológ... more 2 Uno de los problemas más interesantes, pero a la vez más desafiantes, de la conservación biológica es ha-cer compatibles las acciones que generan desarrollo económico con las acciones enfocadas en la preser-vación de los ecosistemas naturales y las especies que los habitan. Un ejemplo claro de esta situación se observa en el caso del desarrollo de la red de ca-rreteras. Cuando están bien planeadas desempeñan un papel fundamental en las estrategias de integra-ción territorial de los países. 1 En México, representan un elemento fundamental para el desarrollo econó-mico y social, ya que son la infraestructura de trans-porte más utilizada. 2 Sin embargo, resulta cada vez más evidente que su construcción y uso tienen fuerte impacto en los hábitats naturales. A nivel de ecosiste-ma, los efectos en los hábitats incluyen la alteración de la dinámica hidrológica y el microclima, así como el incremento en la entrada de contaminación acústi-ca y de partículas generadas por los automotores. E...

Tropical Conservation Science

Baird´s tapir (Tapirus bairdii) is one of the most emblematic mammalian species from Mesoamerica.... more Baird´s tapir (Tapirus bairdii) is one of the most emblematic mammalian species from Mesoamerica. Due to its level of evolutionary distinctiveness and anthropogenic threat this species was recently ranked in 34th position, in terms of its urgency for conservation, among more than 4,000 species of mammals assessed by experts from the Zoological Society of London. Despite its evolutionary and conservation relevance there remain important gaps in knowledge of the basic ecology of this species. Based on camera-trapping data, we estimated Baird´s tapir abundance and analyzed its patterns of daily activity and preference for different altitude intervals in El Triunfo Biosphere reserve, one of the last strongholds for this species in southern Mexico. We also applied a recently developed method (Random encounter model) to estimate tapir density without the need of individual identification. Tapir relative abundance was: 1.3 events/100 camera-trap days and density: 0.12 ind./km 2 . Tapir act...

Encyclopedia of Ecology, 2008

Revista chilena de historia natural, 2005

Habitat loss is a critical threat to tropical biodiversity and its quantification constitutes a c... more Habitat loss is a critical threat to tropical biodiversity and its quantification constitutes a central conservation issue. Typically, assessments have been based on deforestation rates statistics. However, this overlooks the effects brought about by the spatial reconfiguration of the remaining habitat: fragmentation. We present an analysis of fragmentation in a Neotropical site aimed at: (a) devising a protocol for its quantification, (b) using such protocol to provide insights on the ecological consequences of fragmentation, (c) exploring its applicability to address the hypothesis that forest size-inequality decreases with elevation, an indicator of habitat accessibility. We applied the Gini coefficient (G) and the Lorenz curve to analyze fragment-size variation using a satellite-generated map. We also estimated edge effect, fragment shape and isolation. Remaining forest includes 1,005 fragments, ranging from 0.5 to 9.356 ha (median = 0.89). Size inequality was very high (G = 0.928), producing a flattened Lorenz curve. Forty percent of the fragments did not maintain an area free of a 30-m edge effect, and larger fragments showed a marked deviation from ideal circular forms. Eighty-four percent of the fragments lay further than 500 m from the largest forest tract and their size decreased with distance. Fragment size distribution changed with altitude: the Gini coefficient was lowest and forest coverage was greatest at the highest altitude, but inequality peaked at an intermediate elevation. Given the current pace of habitat deterioration, application of similar analyses may improve global assessments of tropical ecosystems and their perspectives for biodiversity conservation.

Oikos, 2007

It has been suggested that the anthropogenically driven loss of herbivorous mammals might lead to... more It has been suggested that the anthropogenically driven loss of herbivorous mammals might lead to changes in the recruitment patterns of tropical rain forest plants, but few studies have examined the explicit mechanisms that might account for this effect. Here we propose a conceptual model linking differential mammalian defaunation and differential plant recruitment. We posit that in the absence of medium/large herbivores but with small rodent granivores still present (i.e. differential defaunation), predation pressure will be greater on small-seeded species than on large-seeded species. We tested such differential predation hypothesis (DPH) by means of a series of experiments directed to assess: 1) seed consumption by small rodents in laboratory cages; 2) seed-removal rates in small rodent enclosures in the field and 3) removal of seeds placed on the forest floor and exposed to either the full complement of mammals or only small rodents. Seeds used in the experiments were arranged in pairs consisting of species from the same taxonomic family but with a contrasting size (large, small). We found: 1) a significantly greater consumption of smaller seeds (a 2.3-to 20.5-fold difference) in cages and 2) a significantly greater removal of small-seeded species (a 3.7-to 65-fold difference) in field enclosures. Results of seed removal experiments in free-access plots and selective exclosures were more complex, with a general absence of significant differences among treatments but we found that predation was in general concentrated on smallseeded species and small rodents were the predominant visitors to the plots. This, together with the overall short distance of dispersal among large seeds suggest that in differentially defaunated forests large-seeded species are more likely to escape predation. We posit that such size related differential predation may lead to the floristic impoverishment observed in some defaunated forests.

The Journal of Wildlife Management, 2011

We present a novel method to improve individual identification of animals based on cameratrapping... more We present a novel method to improve individual identification of animals based on cameratrapping data. The method combines computer tools and human visual recognition to help multiple users to reach identification agreement. Application of this method to a bobcat (Lynx rufus) picture database from the Jasper Ridge Biological Preserve resulted in a progressive increase in identification agreement between 2 users, as measured by the adjusted Rand index (ARI). An initial ARI value of 0.28 increased to a final value of 0.84 (1 ¼ maximum agreement). In contrast, comparisons involving random picture groupings consistently rendered low ARI values ( 0.05). The numbers of individuals named by the 2 users decreased from initial values of 46 and 43 to final values of 25 and 29, respectively. The tool presented here will help researchers and wildlife managers to identify individual mammals and monitor populations. ß 2011 The Wildlife Society.

Integrative Zoology, 2013

Baird's tapir (Tapirus bairdii) is one of the most emblematic mammals of Mesoamerica, but like ot... more Baird's tapir (Tapirus bairdii) is one of the most emblematic mammals of Mesoamerica, but like other largebodied animals, it is facing an increasing risk of extinction due primarily to habitat loss. Mexico's portion of the Mesoamerican Biological Corridor (MBC-M) is located in one of the main strongholds for Baird's tapir. To assess the MBC-M's effectiveness for tapir conservation, we estimated the distribution of the species' potential habitat by applying 2 modeling approaches (Random forests and Maxent) to a set of uncorrelated environmental variables and a 157-point presence dataset. We calculated the extent of tapir habitat in within the MBC-M and modeled new corridors and conservation areas, which we compared to the MBC-M. Moreover, we assessed deforestation patterns in the region. Twenty-seven percent of highly suitable tapir habitat occurred in protected areas, 15% in corridors and 58.3% was outside the MBC-M and associated reserves. The spatial configuration of the MBC-M was partially concordant with the modeled set of conservation areas and corridors. The main dissimilarity was that the modeled corridors traversed forests in Belize and Guatemala to connect conservation areas. Analyses of deforestation since 1993 and human population density in the vicinity of the MBC-M indicated that future conservation efforts should give particular attention to the Montes Azules-El Triunfo Corridor due to greater habitat threat. The MBC-M has a great potential to play a prominent role in the conservation of tapir habitat but there is an urgent need to implement management plans that reinforce and complement this conservation initiative.

Biotropica, 2007

Hunting and habitat loss represent an increasingly common anthropogenic impact. Available evidenc... more Hunting and habitat loss represent an increasingly common anthropogenic impact. Available evidence suggests that defaunation is typically differential: medium/large mammals are most affected while small rodents are less affected, or even favored. In heavily impacted areas, such as Los Tuxtlas, the residual mammalian fauna is dominated by small rodents. We tested the expectation that if small rodents will preferentially attack small-seeded species, large-seeded species may escape predation in the absence of medium/large seed predators and that this may affect germination and, possibly, recruitment. Experiments with caged rodents (Heteromys desmarestianus) under laboratory conditions showed a preference for smaller seeds. A field experiment involving seeds of contrasting size showed that small, unprotected seeds experienced a predation risk 30-times larger than protected seeds, while the effect of protection was not significant for large seeds. These patterns of predation led to significant differences in germination: protected small-seeded species had a fourfold greater germination than unprotected small-seeded species, while germination was not significantly different between exposed and protected large seeds. The observed contrasts in germination suggest that under heavy defaunation, small-seeded species are likely to be penalized by the overabundance of small rodents, while large-seeded species escape predation. Our results are consistent with the observation of dense seedling carpets dominated by large-seeded species in the understory of Los Tuxtlas. We speculate that the patterns we uncovered may explain, at least partly, the impoverished diversity of the understory vegetation that characterizes heavily defaunated understories and that this has the potential to affect forest regeneration.

Biodiversity and Conservation, 1999

Biodiversity and Conservation 8: 16211641, 1999. © 1999 Kluwer Academic Publishers. Printed in t... more Biodiversity and Conservation 8: 16211641, 1999. © 1999 Kluwer Academic Publishers. Printed in the Netherlands. ... Deforestation in Lacandonia (southeast Mexico): evidence for the declaration of the northernmost tropical hot-spot ... EDUARDO MENDOZA and RODOLFO DIRZO ∗ ...

American Journal of Botany, 2009

Secondary forests are replacing mature primary forests in the tropics because of increasing deman... more Secondary forests are replacing mature primary forests in the tropics because of increasing demand for agricultural land to support the growing human population. It is important to determine the potential of these secondary forests to support old-growth forest species, particularly threatened animal groups such as reptiles and amphibians. Moreover, existing studies are biased towards tropical rain forests, even though tropical dry forests (TDF) are comparatively more threatened. Here we examine how different TDF successional stages support old-growth forest species of amphibians and reptiles in the Chamela region, western Mexico. Over the course of two years we conducted seven surveys for amphibians and reptiles in 15 one-ha plots representing four different stages of the succession chronosequence of the TDF, ranging from pasture to old-growth forest. We found that anurans, lizards and snakes did not differ greatly in abundance and species richness among vegetation successional stages. Moreover, dominant species were shared among most of the vegetation stages, indicating low habitat specialization. Herpetofauna species composition did not differ among vegetation stages, and species turnover among stages was relatively low. These results differ greatly from those found in some tropical rainforest sites, where characteristics of herpetofauna communities differ markedly among vegetation successional stages. Our results suggest that secondary TDF in human-dominated landscapes might support substantial reptile and amphibian diversity.