Marlín Pérez-Suárez

La productividad de las plantaciones forestales comerciales depende en gran medida de la fertilidad del suelo y la densidad arbórea. El objetivo de esta investigación fue comparar las características edáficas y su influencia en el desarrollo del arbolado, además de generar modelos altura-diámetro específicos en dos plantaciones de 18 años de Pinus patula. De cada ejemplar se midieron el diámetro normal y la altura, y se calcularon el área basal, la biomasa y el carbono arbóreo. Para caracterizar la fertilidad del suelo se determinaron las propiedades químicas en el perfil 0-30 cm. Finalmente, se ajustaron 14 modelos altura-diámetro. Los árboles de la Plantación A fueron superiores en altura y los de la Plantación B en diámetro, área basal y carbono por árbol, aunque a nivel de superficie, el almacén de carbono aéreo fue similar (75.6 Mg ha-1 en A y 73.7 Mg ha-1 en B). El suelo de la Plantación B registró altos niveles de MOS, N, Ca, Mg y CIC, lo que se reflejó en un mayor almacén de COS. Los modelos altura-diámetro resultaron con coeficientes de determinación bajos (R2=0.25-0.34); el modelo MT1 presentó el mejor ajuste global y residuales con distribución normal. En conclusión, la fertilidad del suelo y densidad de plantación determinaron la productividad y almacenamiento de carbono. Sin embargo, en la modelación altura-diámetro aún es necesario incorporar variables adicionales para mejorar su capacidad predictiva a escala local.

Protected Natural Areas (PNAs) are essential for biodiversity conservation, but they face multiple threats, particularly biological invasions driven by ongoing, intense human activities. The northeastern region of Mexico, covering Coahuila, Nuevo León, and Tamaulipas, has high biodiversity and endemism, with more than 80 PNAs. However, this region has recently recorded the presence of invasive exotic species (IES) with strong potential for spread. This paper analyzes biological invasions by assessing the current and future climatic suitability of three invasive exotic species: collared dove (Streptopelia decaocto), feral pig (Sus scrofa), and Barbary sheep (Ammotragus lervia) in PNAs of northeastern Mexico. The goal is to identify high-risk invasion areas and to inform the design of preventive management and conservation strategies. Using the MaxEnt program to model the ecological niche of these species, potential geographic distribution areas were identified, and the highest-risk zones within the PNAs were outlined. The potential distribution of the three species was estimated to cover approximately 44% of the area of these conservation zones; the most vulnerable areas are Maderas del Carmen, Ocampo, and Cumbres de Monterrey. The obtained models indicate an increased distribution of A. lervia and S. scrofa domesticus under the future climate scenario, whereas the distribution of S. decaocto shows a slight decrease. This study recommends the regional implementation of a monitoring and surveillance strategy for invasive exotic species to guide management actions that interrupt their dispersal and reduce their impacts on native flora and fauna in northeastern Mexico.

Las islas de calor urbanas son un problema importante con diversas consecuencias negativas en las zonas urbanas, generando una disminución en el confort térmico y malestar de los habitantes por el incremento de la temperatura ambiental. Este estudio evaluó la dinámica espacio-temporal de las islas de calor superficiales y el confort térmico urbano en la Zona Metropolitana del Valle de Toluca, México. Se calculó el NDVI y la temperatura superficial terrestre a partir de imágenes Landsat para determinar las islas de calor y el confort térmico urbano. Se observó que existen diferencias en la distribución de las islas de calor a lo largo del año siendo verano y otoño las estaciones más afectadas, principalmente en las áreas más urbanizadas. El confort térmico también muestra variaciones estacionales, donde más del 30% de la superficie evaluada presenta malas condiciones. Las variaciones en la distribución e intensidad de las islas de calor y el confort térmico están influenciadas por los cambios estacionales en la cobertura vegetal, lo cual se evidencia en la correlación negativa observada entre el NDVI y la temperatura superficial terrestre, así como con las islas de calor superficiales. El estudio presenta algunas limitaciones, entre las que se incluyen la baja resolución espacial de las imágenes para capturar detalles finos, su limitada frecuencia temporal, la interferencia de nubes, una capacidad espectral restringida para ciertos análisis y una disponibilidad histórica variable. No obstante, la información generada puede ser de gran ayuda para el diseño de estrategias de planificación territorial que promuevan la sostenibilidad de la zona.

Climate change is altering environmental conditions, which can, in turn, change the geographic distribution and flowering patterns of plant species, affecting both the plants themselves and their pollinators. The responses of melliferous plant species to climate change in southeastern Mexico are poorly understood, which hinders an accurate assessment of their vulnerability and the resulting ecological impacts. As understanding the mechanisms that influence the distribution and susceptibility of these species is essential, the present study examined how climate change affects their potential distribution areas and spatial distribution patterns. This information will serve as reference data for the implementation of conservation strategies and inform the selection of species for reforestation. Ecological niche models were used to estimate the potential distributions of 92 melliferous species under both current environmental conditions and two climate change scenarios projected for the 2041–2060 period (SSP245 and SSP585). Changes in distribution patterns were then assessed by evaluating the range size of each species and analyzing the spatio–temporal trends in species richness. The results revealed that suitable habitats shifted for approximately 80% of melliferous species, with more significant habitat loss observed under the SSP585 scenario than under SSP245. Although a significant decrease in melliferous plant species richness was expected in future scenarios, richness was slightly higher (by 10% for SSP245 and 5% for SSP585) than that observed under current environmental conditions. Under SSP245 conditions, species richness areas expanded to encompass almost the entire region, although this contrasted drastically with the SSP585 scenario, where areas with the highest concentration of species richness contracted significantly and areas with low species richness expanded. These projections are of potential use for conservationists and environmental management authorities, providing crucial insights into the future distributions of several melliferous plant species in the region, the potential impacts of climate change on their habitats, and the vulnerability of threatened species to changing climatic conditions.

Los bosques de alta montaña (>2 500 m) desempeñan un papel crucial en el almacenamiento de carbono a largo plazo. El objetivo de esta investigación fue determinar cómo las variables edáficas, climáticas y vegetales influyen en las existencias de carbono orgánico del suelo (COS) a lo largo de un gradiente altitudinal en el bosque de Pinus hartwegii en el Nevado de Toluca, México. Un total de 140 muestras de suelo superficial (0-15 cm de profundidad) fueron recolectadas a intervalos de 100 m entre los 3 400 y 4 000 m. El COS fue determinado por el método de óxido-reducción, y la densidad aparente (DA) por el método del cilindro. Se analizaron el pH (1:2 KCl) y la textura (método Bouyoucos) del suelo. Los datos climáticos, incluidas la temperatura media anual y las precipitaciones, se obtuvieron a partir del modelo ClimateNA v5.10. Se analizaron las relaciones entre las propiedades del suelo, la estructura de la vegetación y las variables climáticas, comparando parcelas taladas (3 400-3 800 m) y no taladas (3 900-4 000 m). Las existencias de COS aumentaron linealmente con la elevación (r2=0.70; p=0.02), y alcanzaron el máximo valor a los a 4 000 m (173.1±5.2 Mg C ha-1) y el mínimo a 3 700 m (146.8±5.72 Mg C ha-1). Un mayor COS a 4 000 m se asoció con temperaturas más bajas y árboles más grandes. La tala en cotas bajas redujo el COS debido a las alteraciones de la vegetación. Los hallazgos ponen de manifiesto que las reservas de COS varían a lo largo del gradiente de elevación.

In the context of the interaction between natural systems and human activities, seasonal agricultural burning represents a phenomenon with significant impacts on public health and the environment. In addition to the immediate risk associated with uncontrolled fires, there are less obvious threats, such as the long-term consequences on human health due to exposure to invisible pollutants. During these events, the smoke generated, a complex mixture of gases and fine (PM2.5) and coarse (PM10) particles, varies in composition depending on the type of material burned and the combustion conditions. Particulate matter, especially the finest particles (PM2.5), is inhalable and can become deeply embedded in the lungs, contributing to various health problems. Reported effects include acute and chronic respiratory diseases and cardiovascular, cerebrovascular, and gastrointestinal conditions. These impacts are intensified in rural and peri-urban areas where agricultural residue burning is common, highlighting the need to raise public awareness of the risks involved. This document analyzes the main socio-environmental impacts associated with the burning of agricultural biomass, to raise public awareness of the urgency of promoting alternative agricultural practices that minimize dependence on this technique, thus mitigating its detrimental effects on health and the environment.

Information gaps about the distribution of species hamper the evaluation of conservation status and decisions on biodiversity conservation, affecting areas with high species richness and endemism to a greater extent. In this context, carrying out biological inventories in protected and unprotected areas is an important tool to fill these gaps by providing data on the composition, richness, and abundance of species in each locality. The southeastern region of Coahuila (northeast Mexico) is a region where biodiversity research is required, as anthropogenic activities pose a serious threat to the avian diversity of this region. The present study aimed to compare the capacity of protected and unprotected areas to support the richness, abundance, and composition of bird species, as well as providing a list of bird species from eight areas located in this region. The point count method was conducted at the sites, and one-way ANOVA was used to determine the effect of area type on species richness and abundance. Based on our field observations, literature review, and digital databases, the avifauna of these eight areas includes 388 species in 63 families. Of these, 5 species are endemic to Mexico, 6 species are of global conservation concern, and 35 species are of regional conservation concern. The species richness found in this study supports the importance of protected and unprotected areas in southeastern Coahuila. The results of our study highlight the need for further assessment to conserve the avian community, especially considering the increasing threats of anthropogenic disturbance, as well as additional studies that will allow for better characterization of the avifauna of the region. This will help to ensure the conservation of the birds currently threatened by strong anthropic pressure due to the conversion of semiarid ecosystems to agricultural and livestock areas as well as increasing urbanization.

The objective of the present study was to characterize the diversity of life forms and plant community structure along an altitudinal gradient of the Pinus hartwegii treeline ecotone on Nevado de Toluca, Mexico. Plant species in the tree boundary ecotone were sampled, identified and quantified based on plant morphology under adverse conditions (life forms). The diversity of life forms in the ecotone was calculated using Shannon's diversity index and the structure was evaluated in terms of density and abundance of plant species. A total of 43 plant species belonging to 30 genera and 18 families were identified. Chamaefites were the most abundant life form (>50 %); as altitude increased, life form diversity increased, while abundance decreased. Species diversity was proportionally and significantly (pPinus hartwegii treeline ecotone diminished gradually along the treeline ecotone (diffuse form), which was characterized by more pronounced abiotic stress conditions at higher altitudes due to the altitudinal range sampled and because this ecotone represents the distribution limit of forest species and the beginning of grassland distribution. The diversity and distribution of life forms present in the P. hartwegii treeline ecotone may modify microenvironmental conditions or processes and, therefore, they regulate the response of other species associated with climate change.