RASGOS FUNCIONALES DE ESPECIES ARBÓREAS RARAS Y ABUNDANTES EN BOSQUES DE MONTAÑA DEL SUR DE MÉXICO

Los bosques de montaña del sur de México albergan una alta riqueza de especies, sin embargo estos sistemas se encuentran seriamente alterados por influencia humana. El efecto de los disturbios humanos afecta diferencialmente a las especies con base en sus atributos morfo-funcionales para responder efectivamente a las presiones ambientales. En toda comunidad biológica se desarrollan especies que son muy abundantes y especies poco comunes o raras. Estas últimas suelen considerarse más vulnerables ante la transformación de sus hábitats debido a que generalmente tienen bajas densidades poblacionales, están geográficamente restringidas y se encuentran en hábitats específicos. Para probar esta noción, se evaluó la respuesta funcional de especies arbóreas raras y abundantes en los bosques de montaña de la Altiplanicie Central, Montañas del Norte y Sierra Madre de Chiapas, México. Se eligieron cinco rasgos funcionales que reflejan una asociación con la captura de recursos, crecimiento y regeneración de las especies (tamaño del árbol, área foliar, tipo de diáspora, mecanismo de dispersión y afinidad sucesional). Un análisis de clasificación basado en la similitud de rasgos funcionales y distribución mostró que las especies consideradas raras se agrupan en tipos funcionales claramente discernibles de un grupo de especies comunes. El conjunto de especies registradas como raras corresponden a árboles de talla pequeña y crecimiento lento, tolerantes a la sombra, producen frutos drupáceos con dispersión zoocora (aves y mamíferos pequeños) y tienen afinidad sucesional tardía. Lo anterior reconoce los riesgos de la transformación de los bosques sobre estas especies poco comunes y aboga en favor de su conservación

La diversidad natural y su riqueza en la región occidental de Chiapas: implicaciones para el desarrollo local y regional

La región occidental de Chiapas, que consideramos en los objetivos del presente trabajo, comprende los municipios de Cintalapa, Tecpatán, Jiquipilas, Ocozocoautla y Berriozábal, ya que en estos municipios se concentra una diversidad natural que es importante destacar a nivel regional para su protección, conservación y manejo con principios de sustentabilidad ambiental, social y económica en beneicio del mantenimiento de los ecosistemas

Expression of a Deschampsia antarctica Desv. Polypeptide with Lipase Activity in a Pichia pastoris Vector

The current study isolated and characterized the Lip3F9 polypeptide sequence of Deschampsia antarctica Desv. (GeneBank Accession Number JX846628), which was found to be comprised of 291 base pairs and was, moreover, expressed in Pichia pastoris X-33 cells. The enzyme was secreted after 24 h of P. pastoris culture incubation and through induction with methanol. The expressed protein showed maximum lipase activity (35 U/L) with an optimal temperature of 37 °C. The lipase-expressed enzyme lost 50% of its specific activity at 25 °C, a behavior characteristic of a psychrotolerant enzyme. Recombinant enzyme activity was measured in the presence of ionic and non-ionic detergents, and a decrease in enzyme activity was detected for all concentrations of ionic and non-ionic detergents assessed

Rasgos funcionales de especies arbóreas raras y abundantes en bosques de montaña del sur de México

ABSTRACT: The mountain forests of Chiapas, southern Mexico harbor high species richness; however, these systems are seriously altered by human influence. The effect of human disturbances differentially affects species based on their functional attributes to effectively respond to environmental pressures. All biological communities are made up of rare and abundant species. The first are generally considered more vulnerable to the transformation of their habitats because they generally have low population densities, are geographically restricted and are found in specific habitats. To test this notion, we evaluated the functional response of rare and abundant tree species recorded in the mountain forests of the Central Highlands, Northern Mountains and Sierra Madre of Chiapas. Four functional traits were selected that reflect an association with the capture of resources, growth and regeneration of the species (tree size, leaf area, type of diaspora, and dispersion mechanism) with this we define a functional response in terms of its successional affinity. A classification analysis based on the similarity of these traits showed that several of rare species were grouped within a group of common species (Quercus spp.). The set of species registered as rare correspond to small trees and slow growth, tolerant to shade, produce fruits like drupes, zoocoric dispersion (birds and small mammals) and have late successional affinity. The foregoing recognizes the risks of forest transformation on these rare species and advocates in favor of their conservation.RESUMEN: Los bosques de montaña de Chiapas albergan una alta riqueza de especies, sin embargo, estos sistemas se encuentran seriamente alterados por influencia humana. El efecto de los disturbios humanos afecta diferencialmente a las especies con base en sus atributos funcionales para responder efectivamente a las presiones ambientales. En toda comunidad biológica se desarrollan especies que son muy abundantes y especies poco comunes o raras. Estas últimas suelen considerarse más vulnerables ante la transformación de sus hábitats debido a que generalmente tienen bajas densidades poblacionales, están geográficamente restringidas y se encuentran en hábitats específicos. Para probar esta noción, se evaluó la respuesta funcional de especies arbóreas raras y abundantes en los bosques de montaña de la Altiplanicie Central, Montañas del Norte y Sierra Madre de Chiapas, México. Se eligieron cuatro rasgos funcionales que reflejan una asociación con la captura de recursos, crecimiento y regeneración de las especies (tamaño del árbol, área foliar, tipo de diáspora, mecanismo de dispersión) que en conjunto definen una respuesta funcional en términos de su afinidad sucesional. Un análisis de clasificación basado en la similitud de dichos rasgos mostró que las especies raras se agrupan dentro de un grupo de especies comunes (Quercus spp.). El conjunto de especies registradas como raras corresponden a árboles de talla pequeña y crecimiento lento, tolerantes a la sombra, producen frutos drupáceos con dispersión zoocora (aves y mamíferos pequeños) y tienen afinidad sucesional tardía. Lo anterior reconoce los riesgos de la transformación de los bosques sobre estas especies poco comunes y aboga en favor de su conservación

Tropical wetlands and land use changes: The case of oil palm in neotropical riverine floodplains.

Oil palm plantations are expanding in Latin America due to the global demand for food and biofuels, and much of this expansion has occurred at expense of important tropical ecosystems. Nevertheless, there is limited knowledge about effects on aquatic ecosystems near to oil palm-dominated landscapes. In this study, we used Landsat 7 ETM+, Landsat 8 OLI imagery and high-resolution images in Google Earth to map the current extent of oil palm plantations and determined prior land use land cover (LULC) in the Usumacinta River Basin as a case-study site. In addition, we assess the proximity of the crop with aquatic ecosystems distributed in the Usumacinta floodplains and their potential effects. Based on our findings, the most significant change was characterized by the expansion of oil palm crop areas mainly at expenses of regional rainforest and previously intervened lands (e.g. secondary vegetation and agriculture). Although aquatic ecosystem class (e.g. rivers, lagoons and channels) decreased in surface around 3% during the study period (2001-2017), the change was not due to the expansion of oil palm lands. However, we find that more than 50% of oil palm cultivations are near (between 500 and 3000 m) to aquatic ecosystems and this could have significant environmental impacts on sediment and water quality. Oil palm crops tend to spatially concentrate in the Upper Usumacinta ecoregion (Guatemala), which is recognized as an area of important fish endemism. We argue that the basic information generated in this study is essential to have better land use decision-making in a region that is relative newcomer to oil palm boom

Coronaviruses in Bats: A Review for the Americas

The SARS-CoV-2 coronavirus is the focus of attention as it has caused more than three million human deaths globally. This and other coronaviruses, such as MERS-CoV, have been suggested to be related to coronaviruses that are hosted in bats. This work shows, through a bibliographic review, the frequency of detection of coronavirus in bats species of the Americas. The presence of coronavirus in bats has been examined in 25 investigations in 11 countries of the Americas between 2007 and 2020. Coronaviruses have been explored in 9371 individuals from 160 species of bats, and 187 coronavirus sequences have been deposited in GenBank distributed in 43 species of bats. While 91% of the coronaviruses sequences identified infect a single species of bat, the remainder show a change of host, dominating the intragenera change. So far, only Mex-CoV-6 is related to MERS-CoV, a coronavirus pathogenic for humans, so further coronavirus research effort in yet unexplored bat species is warranted

Mechanisms of diversity maintenance in dung beetle assemblages in a heterogeneous tropical landscape

Background Anthropized landscapes play a crucial role in biodiversity conservation, as they encompass about 90% of the remaining tropical forest. Effective conservation strategies require a deep understanding of how anthropic disturbances determine diversity patterns across these landscapes. Here, we evaluated how attributes and assembly mechanisms of dung beetle communities vary across the Selva El Ocote Biosphere Reserve (REBISO) landscape. Methods Community attributes (species diversity, abundance, and biomass) were assessed at the landscape scale, using spatial windows and vegetation classes. Windows were categorized as intact, variegated, or fragmented based on their percent cover of tropical forest. The vegetation classes analyzed were tropical forest, second-growth forest, and pastures. Results We collected 15,457 individuals and 55 species. Variegated windows, tropical forests, and second-growth forests showed the highest diversity values, while the lowest values were found in intact windows and pastures. Landscape fragmentation was positively and strongly related to dung beetle diversity and negatively related to their abundance; biomass was positively associated with forest cover. Beta diversity was the primary driver of the high dung beetle diversity in the landscape analyzed. Discussion The landscape heterogeneity and its biodiversity-friendly matrix facilitate the complementarity of dung beetle assemblages in the Selva El Ocote Biosphere Reserve. Random processes govern beta diversity patterns in intact and variegated windows. Therefore, vegetation cover in the region is sufficient to maintain a continuous flow of dung beetles between forested landscape segments. However, intense anthropic disturbances acted as deterministic environmental filters in fragmented windows and pastures sites, leading to biotic homogenization processes. Our results suggest that increasing habitat variegation in highly fragmented sites is an effective strategy to prevent or buffer homogenization processes in the REBISO landscape

Responses of phyllostomid bats to forest cover in upland landscapes in Chiapas, southeast Mexico

<p>Forests are a key habitat for bats, but tend to be lost and fragmented in some agri-environment schemes. We studied the effects of forest cover change on phyllostomid bats in agricultural landscapes with increment of open areas in an upland region in Chiapas, southeast Mexico. We tested whether with forest cover increase there is a directly proportional response on assemblage species diversity measures, on the capture success and body condition of particular ensembles. Depending on the spatial analysis window, and presumably on vagility, we found positive and significant associations with the sanguivore ensemble’s capture success, as well as with the nectarivore and shrub frugivore ensembles’ body condition. We support the idea that appropriate amounts of forest over small geographic extents may propitiate favorable environments for some phyllostomids, which can also provide important ecological services. Furthermore, the arrangement of ecologically similar species proved to be valuable for exploring adaptive traits, and adequate for conservation strategies of species-rich taxa.</p