Plant-pollinator interactions are essential for maintaining biodiversity and ecosystem functioning. Their analysis through ecological networks enables the assessment of the structure, resilience, and temporal dynamics of these mutualistic systems. However, research on the temporal variation of pollination networks is scarce for arid and semi-arid environments, where biological communities are highly dynamic due to climate variability. Here, we characterized the temporal variation of plant-pollinator networks in a semi-arid scrubland of the southern Chihuahuan Desert across two years with contrasting precipitation. We conducted monthly surveys of pollination interactions, reconstructed temporally discrete networks for three seasons of each year, and evaluated intra- and inter-annual changes in network composition, structure, and robustness to species loss. Interaction variability was modulated by precipitation dynamics, more pronounced among seasons of the same year than between years, and mainly driven by temporal turnover of the plant species in bloom. Greater rainfall was linked to higher plant and pollinator richness and a greater number of connectors, module hubs, and network hubs, especially herbs, dipterans, and lepidopterans. We recorded substantial temporal variation in species' structural roles, yet highlight the importance of generalist bees for network cohesion over time. Seasonal networks showed a persistent compound topology, where nestedness occurs within modules rather than at the whole-network scale. Specialization and modularity tended to increase under drought conditions, accompanied by a decrease in network robustness to species loss. Our results underscore the remarkable diversity and plasticity of plant-pollinator networks in semi-arid environments and provide valuable insights for their conservation under climate change scenarios.
Background: Bletia comprises 56 species distributed throughout the Americas, with its principal center of diversity in Mexico. Among them are Bletia concolor and B. similis, two rare species for which information on morphology, distribution, and ecology is limited. Neither species had been recorded for the last 13 and 62 years, respectively, since their most recent collections. Questions: How do the new records of Bletia concolor and B. similis contribute to the knowledge of their distribution and to the assessment of their conservation status? Studied species: Bletia concolor and B. similis. Study site: San Ángel Zurumucapio, Michoacán, Mexico. Methods: Field explorations were conducted in Michoacán to collect specimens and prepare detailed morphological descriptions. Additionally, specimens in herbaria and digital databases were reviewed. Distribution maps were generated, and the conservation status was assessed following the criteria of the IUCN. Results: New localities in Michoacán were confirmed for Bletia similis, previously known only from Uruapan and now recorded in San Ángel Zurumucapio, as well as for B. concolor, located west of this locality. These records expand the known distribution range and represent the rediscovery of B. similis after 62 years without confirmed records. More complete morphological descriptions were prepared, including characters that had not been previously documented. Both species have restricted distributions and are classified as endangered according to criterion B of the IUCN. Conclusions: The new records expand current knowledge of the distribution, morphology, and ecology of both species, which are considered endangered.
Dendrophthora is a genus of stem-parasitic plants that are commonly known as mistletoes. It exhibits a notable morphological similarity to Phoradendron, which makes differentiation difficult. Traditionally, the two genera are grouped within the tribe Phoradendreae. Molecular analyses have called into question the monophyly of each genus but confirm the monophyly of Phoradendreae. The unique distinction between genera is the number of locules in the anther. However, this feature introduces uncertainties when defining the two genera. Therefore, this study examines the development and floral morphoanatomy of Dendrophthora costaricensis to identify characters that distinguish it from Phoradendron. Standard histological and scanning electron microscopy techniques were employed. Staminate flowers of D. costaricensis have monosporangiate anthers throughout development, while the pistillode develops structures resembling a style and stigmodium. In pistillate flowers, the carpels are arranged in a ring with an internal placenta before ovule formation; there is no vestigial androecium. As the carpels close, a sessile stigma and two ategmic ovules develop, aligned in the dorsal-ventral plane of the flower. For the first time, a nectary has been observed in the gynoecium and pistillode of Dendrophthora. Anther wall development is monocotyledonous and basic, with dehiscence through an apical pore. We describe the development of pollen and unusual embryo sacs. While similarities exist in the development and floral morphoanatomy of the two genera, the presence of monosporangiate anthers and an Allium type of embryo sac development are distinctive features of Dendrophthora. Nonetheless, more research on floral development in Phoradendreae is needed for accurate comparisons.
Construir un pensamiento ambiental crítico y complejo en las nuevas generaciones es una necesidad, dada la urgencia de atender la crisis planetaria actual. El desarrollo de políticas de sustentabilidad podría ser una alternativa para transitar hacia modelos educativos con acciones sustentables integrales. El objetivo de la presente investigación fue analizar el estatus de la sustentabilidad en universidades que adoptaron el Programa Basura Cero Estratégico y sus propuestas de acción frente a los retos que implica integrar la sustentabilidad en la educación superior. La metodología tuvo un enfoque mixto, el método cualitativo se aplicó a través del análisis de contenido y el método cuantitativo en las respuestas de opción múltiple para obtener patrones y frecuencias. Los resultados evidenciaron la falta de claridad en el concepto de sustentabilidad y su confusión con las acciones de gestión ambiental; la presencia de la sustentabilidad en el currículo se localizó en lo disciplinar y se determinó que la mayoría desconoce si existen políticas ambientales dentro de las instituciones; no obstante, la capacitación permitió elaborar propuestas con una visión más amplia de la sustentabilidad y sus alcances. Se concluye que es importante consolidar el concepto de sustentabilidad desde sus raíces teórico-filosóficas para que permee como un proceso de transformación profunda presente en el currículo, en la formación de valores y en actitudes que tiendan a la acción y la transformación social frente a la problemática ambiental. El Programa Basura Cero Estratégico, basado en la economía social y solidaria, puede contribuir al alcance de estos objetivos.
Understanding tropical lake ecosystem responses to anthropogenic disturbance over long timescales is critical for assessing resistance, resilience, and regime shifts; however, such perspectives are rare in the Neotropics. We combined paleolimnological, limnological, and remote-sensing approaches to evaluate the response of a shallow tropical maar lake in the Sierra de Los Tuxtlas (eastern Mexico) to deforestation-driven disturbance over the last 200 years, with emphasis on ecosystem trajectories following peak impact in the late twentieth century. Forest-cover changes were reconstructed from remote images (1976, 2000, 2024), while lake condition was assessed using limnological measurements and diatom assemblages from the water column (2000–2024) and sediments ( 1808–2025). Sedimentary magnetic susceptibility and diatoms documented a major state shift during the 1970s–1980s, coincident with peak deforestation and erosion, characterized by high species turnover and the dominance of disturbance-tolerant taxa (Achnanthidium minutissimum–Fragilaria capucina). This transition contrasts with gradual and elastic responses observed during earlier periods. Despite partial reforestation and landscape stabilization since the 1990s, limnological variables indicate persistent eutrophic to hypereutrophic conditions. However, sedimentary and water-column diatoms revealed ongoing ecological changes, marked by declines in disturbance taxa and increasing abundances of baseline planktonic species (Aulacoseira spp.), indicating an elastic recovery trajectory toward pre-disturbance conditions. Comparisons with an earlier disturbance between AD 100–800 (Classic Mesoamerican period) highlight the importance of disturbance duration and climatic context in determining ecosystem resilience. Our results demonstrate long-term resilience in a tropical lake following intense anthropogenic disturbance, underscoring the value of paleolimnological records for evaluating ecosystem recovery.
