Spatial and temporal variation in interactions between hummingbirds and plants have often been examined, and hummingbirds and insects are known to indirectly interact in networks of nectar plants. In a highland temperate forest in Hidalgo, Mexico some oak trees were heavily infested by honeydew-producing insects (family Margarodidae, tribe Xylococcini, genus Strigmacoccus) and the honeydew was consumed by hummingbirds. Here using survival analysis we investigate how the honeydew produced by dense populations of these margarodids is temporally and spatially partitioned by hummingbirds. We also measured the availability and quality of honeydew exudates, and then we recorded the time until a bird visited and used such resources. Four hummingbird species consumed this resource (Atthis eloisa, Hylocharis leucotis, Colibri thalassinus and Eugenes fulgens). Data from 294 hours of observation on seven focal trees suggested temporal and spatial segregation among visiting birds according to body size and territorial behavior during the most honeydew-limited time. Hummingbird species differed in the daily times they foraged, as well as in the location where honeydew-producing insects were visited on the trees. Temporal and spatial segregation among hummingbird species is interpreted as an adaptation to reduce the risk of aggressive encounters. This may facilitate multispecies coexistence and allow these birds to exploit honeydew more effectively.

El manejo y conservación de un área natural protegida depende en gran parte del conocimiento biológico que se tenga sobre ella. En este estudio se presenta el

Conocer la diversidad y distribución de las especies de aves de un área natural protegida contribuye a desarrollar acciones de conservación. En este trabajo se presenta el listado de aves del Parque Nacional Los Mármoles, Hidalgo, México. Para obtenerlo se conjuntaron observaciones de 5 años de muestreo. Para el registro de las especies se emplearon puntos de conteo y trayectos para las aves diurnas, y estaciones de escucha para las aves con actividad nocturna, registrándose un total de 195 especies de aves. Del total de especies 137 fueron catalogadas como residentes permanentes, 44 como migratorias invernales, 6 como migratorias de verano y 8 como transitorias. El mayor número de especies se registró en el Bosque de Pinus-Quercus (91 especies), seguido por el Bosque de Juniperus (64) y el bosque de Quercus (57). Se registraron 15 especies bajo alguna categoría de riesgo y 26 especies con algún grado de endemismo para México. La diversidad registrada del parque equivale al 38% de la avifauna del estado de Hidalgo y cerca del 17% de la avifauna de México.

Climate change scenarios show that water availability could be decreasing in the near future, adding to the increasing problem of the growing water demands in socioeconomic sectors. The aim of this work was to generate a geographically explicit water balance concerning availability vs. demand in an overpopulated region of Mexico. Water balance and water deficit models were made for three periods of time: 1970–2000, and two future periods of time (2041–2060 and 2061–2080). Three global climate models were used in addition to two different climate scenarios from each (Representative Concentration Pathways (RCP) RCP 4.6 and RCP 8.5). Water demand for socioeconomic sectors was calculated through the water footprint. Water availability was 197,644.58 hm3/year, while that the water demand was 59,187 hm3/year. The socioeconomic sectors with the highest demand were domestic services (48%), agriculture (27%), livestock agriculture (20%), and timber production (5%). The highest water availability areas were not the same as those with the highest demand and vice versa. However, 39% of municipalities had a higher water demand than its availability. A significant reduction in water availability was identified, considering an interval of -15% to 40%. This variation depends on climate models, scenarios, and period of time. Areas with overpopulated cities in the region would have higher pressure on water availability. These results could be used in the implementation of public policies by focusing on adaptation strategies to reduce water deficit in the immediate future.

In Mexico, State Natural Protected Areas are frequently undervalued and rarely studied. The objective of this work was to analyze the process of decree and governance features of Chicamole Ecological Preservation Zone, which protects a cloud forest. An actor map was generated to understand the organization scheme, the external sector involved and their relationships. Semi structured Interviews were conducted both with governmental institutions and local inhabitants to analyze the decree. In spite of the obtained differences in perception, it can be noted that major conservation resulted from legislation. In addition, the presence of well-defined community norms regarding the use of natural resources (especially firewood and water) has encouraged forest conservation. This study shows the importance of a small area in the context of the protected areas in Mexico. The challenges of Chicamole Ecological Preservation Zone include increasing the interaction between sectors, achieving local recognition of the protected zone, and strengthening the social organization and the sustainable use of natural resources through stakeholder inclusion.

El cambio climático está impactando la biodiversidad en el planeta. En México diferentes líneas de investigación se han desarrollado para estudiar los efectos del cambio climático en la distribución de su avifauna. Entender qué enfoques se usan en el país para estudiar este fenómeno puede ayudar a planear mejor los esfuerzos de conservación, determinar qué especies y sitios serían los más afectados, ubicar qué lugares y qué proyectos deberían recibir más atención para asignar los pocos recursos económicos existentes de manera más eficiente. En este documento describimos los enfoques usados por ocho grupos de investigación que estudian los efectos del cambio climático en la avifauna mexicana. El 87.5% usó tres escenarios de cambio climático: A1B, A2 y B2. Todos los gupos, salvo uno, usaron las variables de WorldClim. El 62.5% usó los modelos de circulación general canadiense (CCCMA) y australiano (CSIRO) y el 87.5% usó GARP o MaxEnt para modelar la distribución de especies. Se requiere avanzar en cuatro áreas: (1) elaborar mapas climáticos con mayor resolución, (2) incrementar la colaboración entre grupos de investigación, (3) realizar estudios de identificación de especies y áreas en mayor riesgo, y (4) aplicar los conocimientos que se tienen a la fecha. Proponemos 17 recomendaciones que, de seguirse, podrían determinar que el desarrollo futuro de estas cuatro áreas influya en la conservación de las aves habitando en México. Los resultados de este trabajo podrían ayudar a los científicos, tomadores de decisiones y manejadores de recursos naturales a planear estrategias de conservación apropiadas para el futuro.

Corn (Zea mays L.) is the basis of the Mexican diet. In this country, corn is produced by about 2.5 million small farmers and grown on 8.4 million hectares in rainfed agriculture. However, its production is not enough to meet demand. Climate change may negatively impact corn production, putting Mexico's food security at risk. The main goal of this work was to identify which corn races can find favorable environmental conditions in the future under climate change scenarios in the Sierra Madre Oriental. The Sierra Madre is a region highly vulnerable to climate change; in 2020, corn production was 5,785,561 Mg yr −1 of which 49.87% was from rainfed agriculture.These corn races could be proposed to replace others not tolerant to climate change, mainly at high altitudes. Potential distribution models were obtained for seven highly productive maize races. The projections were generated with the MaxLike algorithm using representative concentration pathways 4.5 and 8.5 scenarios to 2050 and 2070. In addition, general circulation models (CCSM4, GISS.E2-R, and MPI-ESM-LR) were used. Our results show that the Tabloncillo and Tuxpeño races could slightly increase their potential distribution in the future. Both corn races present the highest number of municipalities with adequate environmental conditions for their future presence. As a strategy for adaptation to climate change, it is proposed to replace or complement maize races in high-altitude areas with other tropical ones with greater tolerance to high temperatures, such as the Tuxpeño race. INTRODUCTIONClimate change represents a risk to agricultural production due to the negative impact it would have on yields and the loss of suitable conditions for growing cereal grains (

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