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.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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.
ABSTRACT Changes in atmospheric CO2, ocean temperature, and regional vegetation conditions in Mesoamerica indicate that significant trends in temperature and rainfall may have occurred in the Sierra ...Madre de Chiapas, Mexico. This is an important region for flora and fauna which could be affected by climate trends. We aimed to determine if and where climate trends had occurred in the Sierra Madre and lower elevation regions between 1990 and 2016 (27 years), if these trends were part of longer term (1960-2016 57 years) changes, and how changes in large-scale and regional/local conditions may be influencing these trends. In the Sierra Madre, overall minimum daily temperatures increased, maximum temperatures decreased, and the most significant mean temperature trends were cooler during the 27-yr period. Both the start and end of the wet season trended earlier in the year, and wet season rainfall increased significantly. Trends were not significant during the 57-yr period in the Sierra Madre; however, in the adjacent Pacific coast region, significant warmer temperature trends continued during this period. Within regions, there was large variation in temperature and rainfall changes and some local trends were opposite to the regional averages. Large-scale processes of warming sea surface temperatures in the east coast of Mexico, a change from the positive to negative phase of the Pacific Decadal Oscillation and increases in atmospheric CO2 may be influencing these trends. At the regional scale, increases in dense vegetation and evapotranspiration since 1990 may have created characteristics favoring a positive feedback of higher ocean-based moisture and vegetation-based precipitation cycling.
The Usumacinta floodplain is an exceptional area for biodiversity with important ecosystem services for local people. The main objective of this paper was to estimate reference values and define ...local perceptions of ecosystem services provided by wetlands and overlapping them with spatially explicit socioeconomic and biodiversity indicators. We used the Usumacinta floodplain as an example of a territory where high dependence of rural people on ecosystem services is confronted with development projects that threat the flow of ecosystem services, thus affecting rural people well-being. With a combination of data from remote sensing, global databases of ecosystem service values, local perception of ecosystem services and socioeconomic and biodiversity richness indicators in a spatially explicit framework, we develop a policy-oriented approach for rapid assessment to manage wetlands and maintain people's livelihoods. Regulating and provisioning services are identified as the most relevant ecosystem services in terms of their monetary value and local perceived importance. In a spatially explicit manner, this approach highlights the most valuable wetlands and identifies rural societies that are highly dependent on ecosystem services. Our approach can be replicated elsewhere and could provide valuable information for policymakers to design policies that can contribute to conserve wetland ecosystems where under threat of development.
Increased cattle ranching in Neotropical landscapes has led to human–wildlife conflicts that complicate the relationship between agricultural production and biodiversity conservation. We review the ...literature related to conflicts between livestock production and the common vampire bat Desmodus rotundus, specifically, the factors that influence the incidence of problems caused by bites to cattle. We summarise the strategies proposed to reduce these problems and propose actions from the perspectives of cattle management, landscape ecology and the biology of the common vampire bat. The literature shows that free‐range extensive management systems, where cattle graze in areas with forest cover, near riparian zones, caves, secondary vegetation (generally shrublands and immature trees), and vegetation fragments and edges, increase the implications and the severity of the conflict. As a result of different selection forces, the wing morphology and echolocation characteristics of the common vampire bat facilitate its movement under these landscape conditions, thus favouring a scenario of greater interaction with cattle. We propose the establishment of a ‘buffer zone’ to separate the cattle as far as possible (at least 1 km) from the elements of the landscape that are key for the movement patterns of common vampire bats in cattle ranching areas. The feeding events of this species are positively associated with host availability and landscape elements that provide habitat and connectivity, which shows that the cause of this conflict originates from the process of cattle production and the invasion of the habitat of the common vampire bat. Anti‐rabies vaccination programmes in cattle and forest–cattle separation are the most important strategies to minimise conflict and prevent rabies outbreaks.
RESUMEN EN ESPAÑOL
El aumento de la ganadería en paisajes neotropicales ha llevado a conflictos entre humanos y vida silvestre, que complican la relación entre la producción agropecuaria y la conservación de la biodiversidad. Revisamos la literatura relacionada con los conflictos entre la producción ganadera y el murciélago vampiro común Desmodus rotundus, específicamente, los factores que influyen en la incidencia de los problemas causados por las mordeduras al ganado. Resumimos las estrategias propuestas para reducir estos problemas y proponemos acciones desde las perspectivas del manejo del ganado, la ecología del paisaje y la biología del murciélago vampiro común. La literatura muestra que los sistemas de manejo extensivo, donde el ganado pasta en áreas con cobertura forestal, cerca de zonas ribereñas, cuevas, vegetación secundaria, fragmentos y bordes de vegetación, aumentan las implicaciones y la severidad del conflicto. Como resultado de diferentes fuerzas de selección, la morfología alar y las características de ecolocalización del murciélago vampiro común facilitan su movimiento en estas condiciones del paisaje, favoreciendo así un escenario de mayor interacción con el ganado. Proponemos el establecimiento de una ‘zona de amortiguamiento’ para separar el ganado lo más lejos posible (al menos 1 km) de los elementos del paisaje que son clave para el patrón de movimiento del murciélago vampiro común en áreas ganaderas. Los eventos de alimentación de esta especie se asocian positivamente con la disponibilidad de hospederos y elementos del paisaje que brindan hábitat y conectividad, lo que demuestra que la causa de este conflicto se origina en el proceso de producción ganadera y la invasión del hábitat del murciélago vampiro común. Los programas de vacunación antirrábica en el ganado bovino y la separación entre el bosque y el ganado son las estrategias más importantes para minimizar los conflictos y prevenir los brotes de rabia.
Graphical representation of landscape conditions and vampire bat movement pathways, which determine degree of interaction and attack rates on cattle. The feeding events of the common vampire bat Desmodus rotundus are positively associated with host availability and landscape elements that provide habitat and connectivity. Extensive management systems, where cattle graze in areas with forest cover, secondary vegetation, near riparian zones, caves, and vegetation fragments and edges, increase the severity of the conflict, by favouring a scenario of greater interaction between vampire bat and cattle. We propose a non‐invasive strategy to reduce interactions between vampire bats and cattle: establishing a ‘buffer zone’, where cattle herds are kept away (at least 1 km, or as far as possible) from the landscape elements that are key to the movement patterns of vampire bats.
Bumble bees are an ecologically and economically important group of pollinating insects worldwide. Global climate change is predicted to affect bumble bee ecology including habitat suitability and ...geographic distribution. Our study aims to estimate the impact of projected climate change on 18 Mesoamerican bumble bee species. We used ecological niche modeling (ENM) using current and future climate emissions scenarios (representative concentration pathway 4.5, 6.0, and 8.5) and models (CCSM4, HadGEM2‐AO, and MIROC‐ESM‐CHEM). Regardless of the scenario and model applied, our results suggest that all bumble bee species are predicted to undergo a reduction in their potential distribution and habitat suitability due to projected climate change. ENMs based on low emission scenarios predict a distribution loss ranging from 7% to 67% depending on the species for the year 2050. Furthermore, we discovered that the reduction of bumble bee geographic range shape will be more evident at the margins of their distribution. The reduction of suitable habitat is predicted to be accompanied by a 100–500 m upslope change in altitude and 1–581 km shift away from the current geographic centroid of a species' distribution. On average, protected natural areas in Mesoamerica cover ~14% of each species' current potential distribution, and this proportion is predicted to increase to ~23% in the high emission climate change scenarios. Our models predict that climate change will reduce Mesoamerican bumble bee habitat suitability, especially for rare species, by reducing their potential distribution ranges and suitability. The small proportion of current and future potential distribution falling in protected natural areas suggests that such areas will likely have marginal contribution to bumble bee habitat conservation. Our results have the capacity to inform stakeholders in designing effective landscape management for bumble bees, which may include developing restoration plans for montane pine oak forests habitats and native flowering plants.
Global climate change poses a threat to bumble bees from Mesoamerica by reducing the current potential distribution of these bees in the region, moving their geographic centroid, shifting their altitude distribution to higher altitudes, and reducing their environmental suitability.
Antecedentes: Los tolchés son franjas de árboles dentro del paisaje agrícola yucateco; proporcionan varios servicios ecosistémicos, incluyendo el suministro de material leñoso.
Preguntas e hipótesis: ...¿Existen diferencias en la estructura de la vegetación leñosa de los tolchés a lo largo de la distancia al pueblo y la intensidad de uso? La hipótesis es que los atributos estructurales de la vegetación de los tolchés son afectados negativamente por la intensidad del uso del bosque, que disminuye de los márgenes del poblado, al área agrícola, hasta llegar a la vegetación madura.
Descripción de datos: Se evaluaron los atributos estructurales de tolchés y vegetación madura (VM), se realizó una rarefacción para estandarizar el esfuerzo de muestreo, un modelo lineal univariante seguido de pruebas a posteriori .
Sitio y años de estudio: El estudio se realizó en tolchés y VM de Yaxcabá, Yucatán, de febrero a julio de 2019.
Métodos: Se establecieron 44 unidades de muestreo (UM): 36 UM se ubicaron en tolchés, de 3 grupos diferenciados por su distancia al poblado y 8 UM se ubicaron en VM. Se registraron los individuos leñosos > 2.5 cm de DAP y se evaluaron las diferencias de los valores estructurales de ambas condiciones.
Resultados: La diversidad de los tolchés fueron significativamente superiores a la alcanzada por la VM, relacionada a la distancia al poblado.
Conclusiones: Se determinó la influencia de un patrón de aprovechamiento basado en la distancia al poblado. Niveles intermedios de aprovechamiento favorecen la riqueza y diversidad de los tolchés.
Quantifying patterns of deforestation and linking these patterns to potentially influencing variables is a key component of modelling and projecting land use change. Statistical methods based on null ...hypothesis testing are only partially successful for interpreting deforestation in the context of the processes that have led to their formation. Simplifications of cause-consequence relationships that are difficult to support empirically may influence environment and development policies because they suggest simple solutions to complex problems. Deforestation is a complex process driven by multiple proximate and underlying factors and a range of scales. In this study we use a multivariate statistical analysis to provide contextual explanation for deforestation in the Usumacinta River Basin based on partial pattern matching. Our approach avoided testing trivial null hypotheses of lack of association and investigated the strength and form of the response to drivers. As not all factors involved in deforestation are easily mapped as GIS layers, analytical challenges arise due to lack of a one to one correspondence between mappable attributes and drivers. We avoided testing simple statistical hypotheses such as the detectability of a significant linear relationship between deforestation and proximity to roads or water. We developed a series of informative generalised additive models based on combinations of layers that corresponded to hypotheses regarding processes. The importance of the variables representing accessibility was emphasised by the analysis. We provide evidence that land tenure is a critical factor in shaping the decision to deforest and that direct beam insolation has an effect associated with fire frequency and intensity. The effect of winter insolation was found to have many applied implications for land management. The methodology was useful for interpreting the relative importance of sets of variables representing drivers of deforestation. It was an informative approach, thus allowing the construction of a comprehensive understanding of its causes.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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