Search

El desarrollo de grandes infraestructuras como las carreteras han colocado en grave amenaza a la biodiversidad debido a la mortalidad por atropellamiento de fauna silvestre. Una de las amenazas subyacentes es el fácil acceso para los cazadores; degradación del hábitat alrededor de la carretera por actividades agropecuarias, extracción de petróleo, gas y la minería. Lo anterior coloca en grave riesgo a los primates, con 55 % del total de sus especies en peligro de extinción y disminución de sus poblaciones en un 75 % de sus especies. Este trabajo es el primer estudio en América con un primate arborícola en peligro de extinción y que examina la reducción poblacional sufrida por el impacto de una ampliación de carretera existente en Chiapas, México. La población de Alouatta pigra se redujo en el área de estudio en un 56 % entre el periodo 2012-2017 con 37 atropellamientos. La proporción sexo-edad más afectada es la de inmaduros (de ambos sexos) pasando de 1.2 en 2012 a 0.5 inmaduros por cada hembra adulta en el 2017. Este estudio resalta la disminución poblacional drástica provocada por no realizarse de manera adecuada los estudios de impacto ambiental y las medidas de mitigación en la carretera de estudio.

Military Macaw, Ara militaris (Linnaeus, 1766), is in danger of extinction in Mexico and Vulnerable internationally. We recorded a new locality with a notable presence of this species and identified its nocturnal resting site by the Tehuantepec River, near the community of Santo Domingo Narro in the state of Oaxaca, Mexico. We discuss the importance of considering this population as different from those previously identified in Oaxaca state and discuss the threats to this species’ conservation and implications for its survival at Santo Domingo Narro and in the region.

La depredación es una de las principales causas de mortalidad en poblaciones de anfibios y puede ocurrir en cualquier etapa de su vida. Este estudio registra por primera vez, el avistamiento de depredación sobre la rana arborícola lechosa Trachycephalus typhonius por una mantis en México. Con esto, aumentamos nuestro conocimiento acerca de la diversidad dietaria de este grupo, confirmando su capacidad depredadora sobre una especie de anfibio, en condiciones naturales y sin manipulación.

Among mammals, the order Primates is exceptional in having a high taxonomic richness in which the taxa are arboreal, semiterrestrial, or terrestrial. Although habitual terrestriality is pervasive among the apes and African and Asian monkeys (catarrhines), it is largely absent among monkeys of the Americas (platyrrhines), as well as galagos, lemurs, and lorises (strepsirrhines), which are mostly arboreal. Numerous ecological drivers and species-specific factors are suggested to set the conditions for an evolutionary shift from arboreality to terrestriality, and current environmental conditions may provide analogous scenarios to those transitional periods. Therefore, we investigated predominantly arboreal, diurnal primate genera from the Americas and Madagascar that lack fully terrestrial taxa, to determine whether ecological drivers (habitat canopy cover, predation risk, maximum temperature, precipitation, primate species richness, human population density, and distance to roads) or species-specific traits (body mass, group size, and degree of frugivory) associate with increased terrestriality. We collated 150,961 observation hours across 2,227 months from 47 species at 20 sites in Madagascar and 48 sites in the Americas. Multiple factors were associated with ground use in these otherwise arboreal species, including increased temperature, a decrease in canopy cover, a dietary shift away from frugivory, and larger group size. These factors mostly explain intraspecific differences in terrestriality. As humanity modifies habitats and causes climate change, our results suggest that species already inhabiting hot, sparsely canopied sites, and exhibiting more generalized diets, are more likely to shift toward greater ground use.

Species distribution models (SDMs) are statistical tools used to develop continuous predictions of species occurrence. 'Integrated SDMs' (ISDMs) are an elaboration of this approach with potential advantages that allow for the dual use of opportunistically collected presence-only data and site-occupancy data from planned surveys. These models also account for survey bias and imperfect detection through the use of a hierarchical modelling framework that separately estimates the species-environment response and detection process. This is particularly helpful for conservation applications and predictions for rare species, where data are often limited and prediction errors may have significant management consequences. Despite this potential importance, ISDMs remain largely untested under a variety of scenarios. We performed an exploration of key modelling decisions and assumptions on an ISDM using the endangered Baird's tapir (Tapirus bairdii) as a test species. We found that site area had the strongest effect on the magnitude of population estimates and underlying intensity surface and was driven by estimates of model intercepts. Selecting a site area that accounted for the individual movements of the species within an average home range led to population estimates that coincided with expert estimates. ISDMs that do not account for the individual movements of species will likely lead to less accurate estimates of species intensity (number of individuals per unit area) and thus overall population estimates. This bias could be severe and highly detrimental to conservation actions if uninformed ISDMs are used to estimate global populations of threatened and data-deficient species, particularly those that lack natural history and movement information. However, the ISDM was consistently the most accurate model compared to other approaches, which demonstrates the importance of this new modelling framework and the ability to combine opportunistic data with systematic survey data. Thus, we recommend researchers use ISDMs with conservative movement information when estimating population sizes of rare and data-deficient species. ISDMs could be improved by using a similar parameterization to spatial capture-recapture models that explicitly incorporate animal movement as a model parameter, which would further remove the need for spatial subsampling prior to implementation. © 2019 Foundation for Environmental Conservation. Department of Geography and the Environment, University of Texas at Austin, Austin, TX 78712, United States, Global Wildlife Conservation, Austin, TX, United States Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695, United States Kelly, M.J., Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA 24061, United States Department of Ecology and Evolutionary Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada El Colegio de la Frontera sur, Departamento de Conservacion de la Biodiversidad, Lerma, Campeche, Mexico, Fundación Yaguara-Panama, Ciudad del Saber, Panama Global Wildlife Conservation, Austin, TX, United States, Panthera, New York, NY, United States, Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI, United States Proyecto de Conservación de Aguas y Tierras, ProCAT Colombia/Internacional, Bogotá, Colombia Instituto Internacional en Conservación y Manejo de Vida Silvestre, Universidad Nacional, Heredia, 3000-1350, Costa Rica Instituto Internacional en Conservación y Manejo de Vida Silvestre, Universidad Nacional, Heredia, 3000-1350, Costa Rica Instituto Internacional en Conservación y Manejo de Vida Silvestre

La conservación de especies silvestres requiere implementar acciones basadas en el tamaño, composición y distribución de sus poblaciones. Esta información, sin embargo, está incompleta o desactualizada para muchas áreas de gran importancia biológica. El objetivo del presente trabajo fue contabilizar los monos saraguatos (Alouatta pigra) presentes en la Reserva de la Biosfera Pantanos de Centla (RBPC) para determinar su estado poblacional. La RBPC se dividió en tres zonas que fueron censadas en 2015, 2016 y 2018 por seis grupos de monitoreo comunitario. Un total de 1 929 saraguatos fueron contabilizados, de los que 57 fueron individuos solitarios y el resto se agrupó en 362 tropas con un tamaño promedio, y desviación estándar, de 4.6 ± 2.6 individuos. Más del 60% de las tropas estuvieron formadas de un macho adulto acompañado de una o más hembras adultas y de individuos inmaduros. La proporción sexual entre machos yhembras adultas fue de 1:1.2 y la proporción de individuos inmaduros por hembra adulta fue de 1:1. Los resultados indican que el tamaño y composición de las tropas presentaron valores representativos para la especie, mientras que los valores de los parámetros poblacionales estuvieron dentro de los intervalos reportados para poblaciones en selvas conservadas y fragmentadas. Este es el primer censo completo de primates realizado en un área tan extensa y de difícil acceso en el que se enfatiza la participación de pobladores locales como una estrategia que ofrece ventajas en los censos de primates.

El presente estudio utilizó datos de precipitación y temperatura de 1960-2015 y de Modelos de Circulación Global (MCG) CNRMCM5 y HADGEM2_ES, proyectados a 2045-2069 y 2075-2099; bajo dos rutas de concentraciones de emisiones de gases de efecto invernadero (RCP); 4.5 (constantes) y 8.5 (altas). El objetivo fue probar la hipótesis de que la RBPC se convertiría en un sitio altamente expuesto al aumento en temperatura promedio anual e inundable por el incremento del nivel del mar. Los registros de precipitación y temperatura se descargaron de seis estaciones meteorológicas y capas climáticas de MCG para 2045-2069 y 2075-2099 (RCP 4.5 y 8.5) a una resolución de 1 km2. Las pruebas estadísticas utilizadas en los datos permitieron detectar tendencias de aumento (p < 0.05) a través del tiempo. Debido a la incertidumbre de los escenarios climáticos a futuro, se probaron y analizaron cuatro escenarios. Los resultados indican una tendencia de aumento significativo en temperatura promedio anual de 0.34 a 0.82 ◦C para 1960-2015. Los escenarios climáticos futuros proyectaron que la RBPC sería más cálida, seca e inundada por el incremento del nivel del mar de 13 a 33 cm, lo que propiciará en la formación de un delta costero, abarcando entre 49.3 a 49.5% de la RBPC durante 2045-2099. Conforme con los análisis climáticos, la RBPC podría ser un área altamente expuesta al calentamiento global e incremento del nivel del mar. Este último ocasionaría cambios biogeoquímicos importantes en los cuerpos de agua dulce del área.

Although many large mammals currently face significant threats that could lead to their extinction, resources for conservation are often scarce, resulting in the need to develop efficient plans to prioritize conservation actions. We combined several methods in spatial ecology to identify the distribution of the endangered Baird's tapir across its range from southern Mexico to northern Colombia. Twenty-eight habitat patches covering 23% of the study area were identified, harboring potentially 62% or more of the total population for this flagship species. Roughly half of the total area is under some form of protection, while most of the remaining habitat (~70%) occurs in indigenous/local communities. The network with maximum connectivity created from these patches contains at least one complete break (in Mexico between Selva El Ocote and Selva Lacandona) even when considering the most generous dispersal scenario. The connectivity analysis also highlighted a probable break at the Panama Canal and high habitat fragmentation in Honduras. In light of these findings, we recommend the following actions to facilitate the conservation of Baird's tapir: 1) protect existing habitat by strengthening enforcement in areas already under protection, 2) work with indigenous territories to preserve and enforce their land rights, and help local communities maintain traditional practices; 3) re-establish connections between habitat patches that will allow for connectivity across the species' distribution; 4) conduct additional noninvasive surveys in patches with little or no species data; and 5) collect more telemetry and genetic data on the species to estimate home range size, dispersal capabilities, and meta-population structure. Universidad Nacional, Costa Rica North Carolina State University, United States University of Texas at Austin, United States Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Colombia Universidad de Antioquia, Colombia Universidad Nacional Autónoma de México, México Universidad Nacional Autónoma de Honduras, Honduras Universidad Técnica Nacional, Costa Rica Universidad Michoacana de San Nicolás de Hidalgo, México Instituto Internacional en Conservación y Manejo de Vida Silvestre

Ecological niche modeling is used to estimate species distributions based on occurrence records and environmental variables, but it seldom includes explicit biotic or historical factors that are important in determining the distribution of species. Expert knowledge can provide additional valuable information regarding ecological or historical attributes of species, but the influence of integrating this information in the modeling process has been poorly explored. Here, we integrated expert knowledge in different stages of the niche modeling process to improve the representation of the actual geographic distributions of Mexican primates (Ateles geoffroyi, Alouatta pigra, and A. palliata mexicana). We designed an elicitation process to acquire information from experts and such information was integrated by an iterative process that consisted of reviews of input data by experts, production of ecological niche models (ENMs), and evaluation of model outputs to provide feedback. We built ENMs using the maximum entropy algorithm along with a dataset of occurrence records gathered from a public source and records provided by the experts. Models without expert knowledge were also built for comparison, and both models, with and without expert knowledge, were evaluated using four validation metrics that provide a measure of accuracy for presence-absence predictions (specificity, sensitivity, kappa, true skill statistic). Integrating expert knowledge to build ENMs produced better results for potential distributions than models without expert knowledge, but a much greater improvement in the transition from potential to realized geographic distributions by reducing overprediction, resulting in better representations of the actual geographic distributions of species. Furthermore, with the combination of niche models and expert knowledge we were able to identify an area of sympatry between A. palliata mexicana and A. pigra. We argue that the inclusion of expert knowledge at different stages in the construction of niche models in an explicit and systematic fashion is a recommended practice as it produces overall positive results for representing realized species distributions.

Habitat disturbance disrupts the ecological interactions of mammals, leading to negative consequences for biodiversity. In particular, it is suggested that parasite-host interactions are affected in tropical ecosystems, with parasite diversity reduced as environmental perturbations take place. In this study, we examined whether the disruption of tropical forests affects the presence of parasites in a population of endangered black howler monkeys (Alouatta pigra) that inhabits a highly fragmented landscape in Balancan, Tabasco, Mexico. Our working hypothesis was that increased forest perturbation would negatively affect the incidence of parasitic infections (parasite presence and richness) in black howler monkeys. We conducted a parasitological study and collected stool samples from 65 adult individuals living in 30 forest fragments across a disturbance gradient. We recovered parasite eggs from stool samples using flotation and sedimentation techniques. We selected fragment size and distance from each forest fragment to the nearest village as measures of forest perturbation. We analyzed the effects of forest perturbation on parasite presence and richness using generalized linear models. Other driving factors such as seasonality, host density, and sex were also considered in the models. Gastrointestinal parasite infection was positively related to distance between forest fragments and the nearest human settlement (β = 0.55 ± SE 0.28, z = 2.0, P = 0.05). No effects of fragment size or any other variable considered in the model on the presence of parasite infection were observed. Parasite richness was not affected by any of the measures of forest perturbation, nor by any other variables considered in the analysis. Our findings suggest that an increase in forest perturbation may negatively affect the probability of parasite infection in black howler monkeys, as individuals living in close proximity to human settlements showed a lower presence of parasites. We proposed that the low parasite infection rates recorded in this monkey population reflect synergistic effects associated with both the alteration of the parasite-primate network, as well as the low resilience of parasites to thrive in a disrupted ecosystem.

Aim We test a new species distribution modelling (SDM) framework, while comparing results to more common distribution modelling techniques. This framework allows for the combination of presence-only (PO) and presence-absence (PA) data and accounts for imperfect detection and spatial bias in presence data. The new framework tested here is based on a Poisson point process model, which allows for predictions of population size. We compared these estimates to those provided by experts on the species. Species and Location Presence data on Baird's tapir (Tapirus bairdii) throughout its range from southern Mexico to northern Colombia were used in this research, primarily from the years 2000 to 2016. Methods Four SDM frameworks are compared as follows: (1) Maxent, (2) a presence-only (PO) SDM based on a Poisson point process model (PPM), (3) a presence-absence (PA) SDM also based on a PPM and (4) an Integrated framework which combines the previous two models. Model averaging was used to produce a single set of coefficient estimates and predictive maps for each model framework. A hotspot analysis (Gi*) was used to identify habitat cores from the predicted intensity of the Integrated model framework. Results Important variables to model the distribution of Baird's tapir included land cover, human pressure and topography. Accounting for spatial bias in the presence data affected which variables were important in the model. Maxent and the Integrated model produced predictive maps with similar patterns and were considered to be more in agreement with expert knowledge compared to the PO and PA models. Main conclusions Total abundance as predicted by the model was higher than expert opinion on the species, but local density estimates from our model were similar to available independent assessments. We suggest that these results warrant further validation and testing through collection of independent test data, development of more precise predictor layers and improvements to the model framework.

Las areas naturales protegidas (ANP) son muy importantes para frenar el impacto antropico. Sin embargo, es dificil medir su efectividad debido a que se carece de informacion de referencia. Evaluamos la variacion espaciotemporal en la estructura y composicion de la comunidad de mamiferos medianos y grandes (> 500 g) en la Reserva de la Biosfera Selva El Ocote (REBISO) y comparamos la riqueza de especies registradas entre 2013 y 2016 vs. las especies reportadas en 1996. Ademas, comparamos la riqueza y la composicion de especies entre la zona nucleo, la de amortiguamiento y el area de influencia. En 2,835 dias camara-trampa se registraron 19 especies (79.2% de las previamente reportadas) pertenecientes a 13 familias y 7 ordenes. Cuniculus paca y Dasyprocta mexicana fueron las especies mas frecuentes. Leopardus pardalis y L. wiedii fueron mas frecuentes en la zona nucleo que en la zona de amortiguamiento o area de influencia, mientras que Didelphis virginiana y Nasua narica , fueron mas frecuentes en la zona de amortiguamiento o en el area de influencia que en la zona nucleo. Los muestreos multianuales son fundamentales para tener una linea base que permita evaluar el efecto de las perturbaciones sobre la biodiversidad en las ANP.

Across the tropics, landscapes of continuous rain forest are being replaced by forest fragments embedded in a matrix of pastures and farmlands. This conversion has endangered many species, including arboreal primates. Species vary, however, in how they are able to supplement their diets from the matrix, although this is rarely studied in primates. We studied two groups of black howlers (Alouatta pigra) for a total of 1156 h, one inhabiting a smaller fragment (0.4 ha) and the other a larger fragment (20 ha). monkeys inhabiting the smaller fragment spent more time in the matrix than in the habitat fragment, spending 50 % of their time (335 of 667 h) in an abandoned mango (Mangifera indica) plantation, 8.8 % in scattered trees, and 0.2 % in pastures. In contrast, monkeys in the larger fragment spent 75 % of their time (368 of 489 h) in the forest fragment and only 25 % of their time in the matrix. Feeding in the matrix accounted for 53 % and 12 % of the foraging time for groups in the smaller and larger fragments respectively. We suggest that Alouatta pigra can use resources in the matrix to supplement their diet by means of crop raiding or taking other resources in many fragmented landscapes and that this may be true also for many fragment-dwelling primates. It is important to include a consideration of the matrix in conservation planning, considering both the total resources available to primates and the consequences of crop raiding for farmers.

Presentamos el primer registro del capuchino tricolor (Lonchura malacca) en el estado de Chiapas, con lo cual suman ya tres los estados con avistamientos de esta especie exótica en México. Los reportes previos de avistamiento de L. malacca en el país han sido en Yucatán, en 1993, y Quintana Roo, en 2004. El presente registro sugiere una posible ampliación en la distribución de L. malacca en México.

In the Mexican state of Chiapas the rainforest has been cleared, to make way for crops and extensive cattle ranching, at an annual rate of 12.4% since 2002. The conservation status of the Endangered black howler monkey Alouatta pigra in these fragmented landscapes in north-eastern Chiapas has not previously been examined. We therefore surveyed A. pigra populations in the municipality of Playas de Catazajá during 2004–2006 to obtain population and habitat data for this species in 115 fragments of remnant vegetation. A geographical information system was used to determine the variables (fragment size, and distances to the nearest fragment, human settlement and water body) that could be used to generate an index of habitat potential for A. pigra. We estimated a population of 659 individuals and a mean troop size of 5.0 ± SE 2.3. The adult male : female ratio was 1 : 1.4, the adult female : juvenile ratio 1 : 0.6 and adult female : immature ratio 1 : 0.8. The index of habitat potential indicates that 12% of the fragments have a high conservation potential for A. pigra. This index is a valuable tool for evaluating the conservation status of this species and its habitat, and can be expanded to include additional variables, thus allowing for a more comprehensive assessment.

Uncommonly observed behaviors were systematically recorded in a troop (n = 9 individuals) of black howler monkeys (Alouatta pigra) inhabiting a small forest fragment (1.7 ha) in Leona Vicario, Balancán, Tabasco, Mexico. Between February 2002 and January 2003 (n = 499 h), we observed behaviors such as ground travel (85 occasions, total = 269 min/10.8% of total locomotion time), ground foraging (eight occasions, total = 50 min/0.84% of total feeding time) and drinking water pooled in tree holes (20 times, total = 93 min/0.31% of total activity time). Total time (412 min) for these non-resting behaviors (feeding and locomotion on the ground) is almost equivalent to time devoted to social activities (420 min). These behaviors indicate that howler monkeys may be responding to pressures imposed by the small size of the fragment by adopting diverse strategies to cover their basic nutritional needs in this environment. They accomplish this while exposing themselves to potential predation by coyotes (Canis latrans), as was observed once during the study. It is likely that these behaviors are occurring at an increasing rate among monkeys in fragmented landscapes.

Se informa sobre el comportamiento alimentario del mono aullador negro (Alouatta pigra Lawrence) durante un ciclo anual (Febrero 2002 a Enero 2003) en un remanente boscoso de 0.164 ha rodeado de potrero en la Ranchería Leona Vicario, Balancán, Tabasco, México. La presente investigación se constituye como el primer estudio sistemático para el estado de Tabasco sobre la dieta de esta especie. Mediante el método Animal Focal, se registraron observaciones conductuales (n= 499 h) de las actividades de una tropa de A. pigra (n= 9; 3 MA, 2 HA, 2 J, 2 In), de las cuales el 19.6 % (96 h 55 min) fueron dedicadas a la alimentación. En el área de estudio se registró el consumo de 15 spp. (55.5 %) de un total de 27 especies de plantas presentes en el área de estudio. El número de especies usadas por mes variaron desde 5 a 12 con un promedio de 9 especies. Las hojas jóvenes y los frutos maduros fueron las partes vegetales principales en la dieta de los monos aulladores y los porcentajes de uso fueron 70.8 % y 11.4 % respectivamente. Entre las diferentes especies de plantas consumidas por los aulladores, se mostró preferencia (X2= 25060, p>0.001, gl. =14) por algunas que se presentaban poco abundantes en el sitio de estudio (p.e. Andira inermes con 0.007 ind/ha). Bajo estas condiciones de perturbación, el consumo de diferentes especies vegetales, así como de sus diferentes partes a lo largo del año indica que los monos aulladores negros poseen una gran flexibilidad alimenticia que les ha permitido sobrevivir en el área de estudio. Sin embargo, se presenta como un reto el investigar la viabilidad poblacional de la especie en años futuros.

Composition of the landscape matrix of surrounding forest fragments is thought to be critically important to the survival of arboreal primates because it offers structures that help the animals move between fragments and other foraging sites. However, little is known about the composition of the matrix used by these animals. The aim of this study was to quantitatively assess the importance of the landscape matrix and its effects on primate abundance, using black howler monkeys (Alouatta pigra) living in a landscape fragmented by the expansion of agriculture and pastures for livestock in southeastern Mexico. In 2008, a complete census of the monkeys was carried out across the 2000-ha landscape matrix, and for every site where we observed monkeys, we recorded canopy height, tree basal area, food-source abundance, and distance to the nearest fragment. A total of 244 howler monkeys, distributed among 48 groups (including six solitary males) were counted in the matrix. Mean troop size was 5.6 ± 2.8 individuals, and the mode was three individuals. The highest number of troops and greatest howler monkey abundance were recorded in the isolated trees, the eucalyptus plantation, and orchards. A generalized linear model revealed that monkey abundance tended to be higher in matrix elements with higher canopy height, greater food availability, and closest to rainforest fragments. These results suggest that it is necessary to take into account the many elements of the landscape when drawing up conservation and habitat management plans, particularly in order to establish connectivity among the fragments and elements of the matrix with native trees.

We evaluated the habitat and populations of the black howler monkey (Alouatta pigra) in the municipality of Balancan, Tabasco, southeastern Mexico, using a combination of field surveys and remotely sensed data. We identified 21,937 ha of remnant vegetation composed of 1,348 fragments. Fragments separated by up to 200 m were grouped into "clusters" of fragments in accordance with the maximum observed open distance crossed by A. pigra. A total of 11% or 84 of the 772 clusters identified through remote sensing were selected at random, and for these we determined the vegetation type, canopy height, area, and distance to the closest human settlement. In these same 84 clusters, which included a total area of 9,817 ha, from October to June of 2006 we located a total of 1,064 black howler monkeys, including 228 troops and 49 solitary monkeys. A. pigra was found in 62 (74.7%) of all clusters visited, with a cumulative area of 6,032 ha. Troops varied in size from 2 to 15 individuals (average 6.0+/-2.9 ind/troop). Adults were 67% (n=716) of detected individuals, whereas juveniles were 20.5% (n=218) and infants were 12.5% (n=133). We found black howlers to occur at an ecological density of 10.8 ind/km(2), which is low in comparison with A. pigra in other fragmented and conserved sites. We found a statistically significant relationship between the area of clusters and the abundance of howler monkeys (r(2)=0.2, F=10.47, gl=3, P=0.002). In addition, the probability of finding A. pigra was greater in secondary vegetation, riparian vegetation, tropical dry forest, undisturbed tropical oak forest, and palm forest (F=12, gl=3, P