Gilberto Pozo-Montuy

Aquatic ecosystems are currently facing anthropogenic pollution, mainly derived from agricultural, industrial, and urban runoff, including heavy metals, polycyclic aromatic hydrocarbons (PHAs), pesticides, fertilizers, and untreated wastewater discharges. To understand the impact of environmental contamination on fish, this research compared cytochrome P450 1A (CYP1A) gene expression in armored catfish across three locations in the lower Grijalva–Usumacinta River basin known for varying levels of pollution. Samples from the Ribera Alta, the Bitzales River, and the Chaschoc lagoon were collected during the dry and rainy seasons. We isolated RNA from liver samples, which were subsequently converted to cDNA. We used quantitative PCR to analyze CYP1A gene expression. Results showed that, of the three locations, Ribera Alta demonstrated the highest expression during the rainy season. Only in Chaschoc Lagoon did we observe significant differences between seasons (p = 0.03). This indicates that seasonal factors and the presence of pollutants in the water bodies and sediments likely play a role in regulating CYP1A gene expression in this fish species.

Wildlife-vehicle collisions (WVCs) threaten biodiversity, particularly in the Gulf of Mexico, where road expansion increases habitat fragmentation. This research analyzes WVC patterns in southeastern Mexico, estimating collision rates across road types and assessing environmental factors influencing roadkill frequency. Field monitoring in 2016 and 2023 recorded vertebrate roadkills along roads in Campeche, Chiapas, and Tabasco. Principal Component Analysis (PCA) and Generalized Additive Models (GAM) evaluated landscape influences on WVC occurrences. A total of 354 roadkill incidents involving 73 species of vertebrates were recorded, with mammals accounting for the highest mortality rate. Hotspots were identified along Federal Highway 259 and State Highways Balancán, Frontera-Jonuta, and Salto de Agua. Road type showed no significant effect. Land cover influenced WVCs, with cultivated forests, grasslands, and savannas showing the highest incidences. PCA identified temperature and elevation as key environmental drivers, while GAM suggested elevation had a weak but notable effect. These findings highlight the risks of road expansion in biodiversity-rich areas, where habitat fragmentation and increasing traffic intensify WVCs. Without targeted mitigation strategies, such as wildlife corridors, underpasses, and road signs, expanding infrastructure could further threaten wildlife populations by increasing roadkill rates and fragmenting habitats, particularly in ecologically sensitive landscapes like wetlands, forests, and coastal areas.

Diaemus youngii y Macrophyllum macrophyllum son dos especies de murciélagos que habitan en México, pero cuentan con pocos registros en colecciones. El objetivo de este estudio es presentar datos que amplían la distribución geográfica de D. youngii para la vertiente del Pacífico mexicano en Chiapas y añadir registros de M. macrophyllum en esta región. Los muestreos se llevaron a cabo en tres periodos con una duración de siete noches: diciembre de ٢٠٢٠, mayo de ٢٠٢١ y julio de ٢٠٢٢ en Villa Comaltitlán, Chiapas. Se usaron tres redes de niebla, colocadas dentro de la vegetación cercana al río Papagayo e inmersas en una plantación de palma de aceite. Con un esfuerzo de ٦,٢١٦ m x hr de muestreo se obtuvieron ٣٨٦ registros de murciélagos pertenecientes a ١٢ especies, incluyendo a D. youngii y M. macrophyllum. Se capturó ١ macho adulto de D. youngii y ٤ de M. macrophyllum. Un quinto registro de M. macrophyllum ocurrió de manera fortuita en la carretera Pijijiapan - Tonalá, con un individuo atropellado. El registro de D. youngii es el primero para la costa del Pacífico de Chiapas, ya que el registro más cercano se encuentra a ١٩٧ km en línea recta del sitio de captura, en la Reserva de la Biosfera Montes Azules. Los registros de M. macrophyllum complementan los datos previos en la vertiente del Pacífico. La aportación de los nuevos registros de D. youngii y M. macrophyllum es valiosa para complementar el conocimiento de su distribución.

Lontra annectens (nutria neotropical) está presente en una variedad de cuerpos de agua. Su abundancia poblacional varía a través de su distribución y está asociada a las características físico-ambientales, incluyendo la actividad antropogénica. Este estudio proporciona información sobre el tamaño poblacional de L. annectens en el río Tehuantepec y el posible uso de las estructuras de drenaje como pasos para la nutria, previo a la construcción de la autopista Mitla-Tehuantepec. Se recorrieron 49.3 km de longitud del río Tehuantepec para la búsqueda de rastros durante 2013. Se obtuvieron 678 registros en 246 km recorridos: 511 excretas, 76 letrinas, 79 huellas, 10 madrigueras, y 1 avistamiento. La abundancia relativa varió de 0.83 a 5.74 registros/km recorridos sin diferencias significativas. El número de nutrias varió de 0.004 a 0.03 nutrias/km a través del índice de Gallo y de 0.33 a 2.93 nutrias/km para el índice de Eberhardt y Etten. De las 316 estructuras de drenaje dentro del tramo de la autopista, 117 (37%) presentaron al menos un rastro en un radio de 0.5 km. La estimación del tamaño poblacional de L. annectens en el río Tehuantepec se ubica entre las más altas registradas previamente. La coincidencia entre los rastros y las estructuras de drenaje puede ser una señal del posible uso por parte de la especie, ante la falta de pasos diseñados para L. annectens en la autopista Mitla-Tehuantepec.

In May and June 2024, a die‐off of Mexican mantled howler monkeys (Alouatta palliata mexicana) occurred in southern Mexico. This commentary documents the event, attributing it to extreme heatwaves, drought, wildfires, and habitat impoverishment. Despite their reported resilience to habitat disturbances, mantled howler monkey mortality rate in some areas reached 31%. Key evidence points to heatstroke as the primary cause of death, exacerbated by limited hydration and reduced dietary diversity in disturbed habitats. Immediate responses included community‐led rescues (e.g., hydrating the monkeys), coordination of rescue activities by nongovernmental organizations (NGOs) (e.g., managing donations), involvement of scientists (e.g., monitoring of primate populations), and assistance from government officials (e.g., providing legal support for animal management). This event underscores the urgency of developing action plans to prevent and attend future crises. Among other actions, we highlight (i) establishing primate care infrastructure with medical and rehabilitation centers; (ii) developing protocols and training programs to ensure rapid crisis response; (iii) fostering collaboration among government, NGOs, and academic institutions for effective crisis management; and (iv) developing targeted research on climate change impacts, predictive models, and long‐term health monitoring. We emphasize the critical need for coordinated conservation efforts to protect wild primates and maintain natural ecosystem resilience in the face of escalating climate challenges.

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.

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.

Wildlife conservation requires performing actions based on the size, composition, and distribution of their populations. This information, however, is incomplete or outdated for many areas of great biological importance. The goal of this study was counting the Black saraguatos (Alouatta pigra) in the Biosphere Reserve of Pantanos de Centla (BRPC) to determine their population status. The Reserve was divided into three zones that were censused in 2015, 2016, and 2018 by six community monitoring groups. A total of 1 929 saraguatos were counted, of which 57 were solitary individuals and the rest of them were grouped into 362 troops with an average size, and standard deviation, of 4.6 +/- 2.6 individuals. More than 60% of troops were formed by an adult male, one or more females, and immature individuals. The sex ratio between adult males and females was 1:1.2 and the ratio of immature individuals to adult females was 1:1. These results suggest that troop size and composition were representative of the species, while population parameters were within the ranges reported for populations in conserved and fragmented forests. This is the first complete census carried out in a large and difficult to access area, which emphasize the local people involvement as a strategy that offers advantages during the primate population censuses.

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.

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.