Estado del conocimiento y aportes a la flora vascular del bosque seco del Tolima

In Colombia, dry tropical forests represents one of the most degraded, fragmented and less studied ecosystems, constituting a priority research element, therefore, in this paper, we defined the list of plants for dry forests in the department of Tolima supported by TOLI Herbarium collections and records of the authors, which were obtained in botanical expeditions over the last 4 years at these forests. The best sampled municipalities and the places without collections were defined. For the first time for this ecosystem, we registered in Colombia and South America Ophellantha spinosa Standl in The Neme Reserve in Coello, in dry forest in Tolima to Anthodon decussatum Ruiz & Pav., Gustavia santanderiensis R.Knuth and Simira rubescens (Benth.) Bremek. ex Steyerm. During curatorial process of collection, two isotypes were found to be determined, corresponding to Trichilia oligofoliolata M. E. Morales and Trichilia carinata M. E. Morales, these were considered endemic to the dry forests of northern Tolima. We conclude that the best collected places are agricultural research centers and they have generally historical collections including mainly species associated with crops such as weeds and grassland. Thus, forests that are not part of large monocultures in the fertile terraces are partly unexplored and could harbor important and unknown species to the area.En Colombia los bosques secos representan uno de los ecosistemas más degradados, fragmentados y menos estudiados, lo cual hace que se enmarque en un factor prioritario para la investigación, por esto en este trabajo se definió el listado de plantas para los bosques secos en el departamento del Tolima, empleando en ello las colecciones de los Herbarios TOLI y COL. Se determinaron los municipios mejor muestreados y los lugares sin colectas. Se registra para el Tolima y segunda vez para Colombia Acidocroton gentryi Fern. Alonso & R. Jaram. (Euphorbiaceae) en la Reserva El Neme en Coello; para bosque seco en Tolima, Anthodon decussatum Ruiz & Pav. (Celastraceae), Gustavia santanderiensis R.Knuth (Lecythidaceae), el género Palmorchis de la familia Orchidaceae y Simira rubescens (Benth.) Bremek. ex Steyerm. (Rubiaceae). Se concluye que los lugares más colectados obedecen a centros de estudios agrícolas y que son, en general, colectas históricas que incluyen principalmente especies asociadas a cultivos como Herbáceos y pastizales. De esta forma, los bosques que no se encuentran relacionados con los grandes monocultivos de las terrazas fértiles, siguen parcialmente inexplorados y pueden albergar importantes especies desconocidas para la zona

INDICADORES MORFOMÉTRICOS FOLIARES PARA LA DETECCIÓN TEMPRANA DEL ESTRÉS HÍDRICO DE Gmelina arborea Roxb. EN SISTEMAS AGROFORESTALES, SANTAFÉ DE ANTIOQUIA

Leaf asymmetry was assessed in individuals of Gmelina arborea Roxb. growing under different soil water conditions in a dry forest agroforestry system (AFS), in Santafé de Antioquia. Leaf asymmetry was correlated with additional morphometric parameters, such as angle of insertion of the petiole in the leaf in mature individuals and the ratio of the number of teeth on the edge of the blade in juvenile leaves to propose new indicators of early stage stress. The models generated had R2 values of above 75 %, which support their use in identifying developmental instability as an early indicator of water stress. Similarly, leaf diversity was assessed between the two phenotypes of leaves (ML and JL), with conventional morphometric variables (length of the midrib, leaf perimeter, specific leaf area and dry matter), because they are characters related to leaf form and function. There were marked differences in form and behavior between the two types of leaf indicating a further source of instability evident from leaf ontogeny. The results of this work will allow the optimization of management strategies of G. arborea in the AFS as an early indicator of water stress.En esta investigación se evaluó la asimetría foliar (ASF) en individuos deGmelina arborea Roxb., establecidos en sistemas agroforestales (SAF), en áreas de bosque seco tropical, en el municipio de Santafé de Antioquia. Estos individuos crecen bajo diferentes condiciones hídricas del suelo. La ASF se correlacionó con nuevos parámetros de tipo morfométrico como el ángulo de inserción del peciolo en la lámina foliar (AIP) en individuos maduros y la razón entre el número de dientes del borde de la lámina (RDF) en las hojas de individuos juveniles, propuestos como nuevos indicadores del estado temprano de estrés en la especie. Los modelos generados presentaron valores de R2superiores al 75 %, lo que soporta su utilización como indicadores tempranos del estrés hídrico en G. arborea. Adicionalmente, se evaluó la diversidad foliar entre los dos tipos de hojas (HM y HJ), con variables morfométricas convencionales, tales como la longitud de la nervadura principal (L), perímetro de la hoja (P), área foliar específica (AFE) y materia seca (DW), puesto que son caracteres relacionados con la forma y funcionalidad foliar. De lo anterior se dedujo que existen marcadas diferencias en forma y comportamiento entre los dos tipos de hojas. Los resultados de este trabajo permitirán la optimización de estrategias de manejo de G. arborea en el SAF, gracias a la identificación temprana de la presencia de este tipo de estrés. Esto permitiría mantener permanentemente el dosel de los árboles y así mejorar el ambiente de productividad de los cultivos agrícolas asociados

PATRONES DE ARQUITECTURA FOLIAR ASOCIADOS AL CRECIMIENTO FUNCIONAL DE CINCO ESPECIES LEÑOSAS NATIVAS DE LA CORDILLERA ORIENTAL UTILIZADAS EN RESTAURACIÓN ECOLÓGICA EN LA SABANA DE BOGOTÁ

This research was carried out in La Poma Ecological Park, which is located on the Sabana de Bogotá and corresponds to an area of Lower Montane dry forest. Frequent incidences of frost means that it is a challenging environment for vegetation growth. Leaf components, patterns of canopy architecture and functional growth parameters were evaluated and characterized for populations of Abatia parviflora (Ap), Dodonaea viscosa (Dv), Escallonia paniculata(Ep), Baccharis macrantha (Bm) and Quercus humboldtii (Qh) that ranged in age from one to ten years. We hypothesized that particular growth tendencies were associated with a specific architectural pattern. Morphometric leaf, canopy architecture and functional growth variables were evaluated for these species. An Anova (P <0.05) was performed for each variable along with a multiple range Tukey test that separated the means. We found that the species with higher photosynthetic efficiency and higher dry matter accumulation capacity expressed in biomass were Qh and Dv. These species have an erectophil canopy with the highest light absorption. The other species (Ap, Ep, and Bm) have planophil and plagiophil canopies that have a lower productive capacity. This work provides information on the potential use of woody shrub species in environments where trees have restricted growth.Esta investigación se realizó en el Parque Ecológico la Poma que hace parte de los paisajes de la Sabana de Bogotá y corresponde a un bosque seco Montano Bajo (bs-Mb), con presencia recurrente de heladas, lo que genera un ambiente crítico para el crecimiento de la vegetación. Se evaluó y se caracterizó el componente foliar, los patrones que definen la arquitectura de dosel y los parámetros de crecimiento funcional, para poblaciones de las especies Abatia parviflora (Ap), Dodonaea viscosa (Dv), Escallonia paniculata (Ep), Baccharis macrantha (Bm)y Quercus humboldtii (Qh), con edades entre uno y diez años, bajo la hipótesis que plantea la existencia de tendencias particulares de crecimiento asociadas a un patrón arquitectural específico. Se evaluaron variables de tipo morfométrico foliar, variables para la caracterización de la arquitectura de dosel y variables de crecimiento funcional para las especies mencionadas. Para cada variable se realizó un análisis de varianza (p < 0.05) y en el test de rango múltiple se utilizó la prueba Tukey para la separación de las medias. Como resultado se encontró que las especies con mayor eficiencia fotosintética, y por consiguiente, con mayor capacidad de acumulación de materia seca expresada en la biomasa fueron Qh y Dv, las cuales presentaron un dosel de tipo erectófilo que generó la mayor absorción lumínica. Las demás especies (Ap, Ep y Bm) tienen doseles planófilos y plagiófilos que se pueden ligar a una menor capacidad productiva. Este trabajo vislumbra el potencial de las especies leñosas arbustivas para ser utilizadas en ambientes donde los arboles tienen restringido su crecimiento

Casos de estudio en México y Latinoamérica

Ante la presencia de conflictos sociales y territoriales, las comunidades organizadas buscan estrategias de solución y confrontación. Es el estudio de dichos movimientos, lo que motiva a la publicación de éste libro: Respuestas comunitarias ante conflictos ambientales. Casos de estudio en México y Latinoamérica, reúne catorce textos que analizan las respuestas sociales y documentan la acción colectiva de comunidades que se han organizado para autogestionar soluciones ante conflictos territoriales, económicos y ambientales, en su propio entorno. Las aportaciones de investigadores y activistas, desde enfoques teóricos y metodológicos particulares, exponen casos de estudio sobre organizaciones formales e informales que se han conformado para afrontar los retos que representan proyectos productivos como fábricas cementeras, mineras, puertos, productores de energía, entre otros. Los enfoques analíticos tocan también temas nodales en el estudio de la acción colectiva como la ética, el despojo, los derechos humanos y las estrategias de comunicación y visibilización. Este material, que reúne estudios hechos en distintos lugares de México y Latinoamérica, es un compendio de métodos de investigación y un acercamiento al estudio de los movimientos sociales.UAEMEX, CONACyT, SE

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Large-scale patterns of turnover and basal area change in Andean forests

General patterns of forest dynamics and productivity in the Andes Mountains are poorly characterized. Here we present the first large-scale study of Andean forest dynamics using a set of 63 permanent forest plots assembled over the past two decades. In the North-Central Andes tree turnover (mortality and recruitment) and tree growth declined with increasing elevation and decreasing temperature. In addition, basal area increased in Lower Montane Moist Forests but did not change in Higher Montane Humid Forests. However, at higher elevations the lack of net basal area change and excess of mortality over recruitment suggests negative environmental impacts. In North-Western Argentina, forest dynamics appear to be influenced by land use history in addition to environmental variation. Taken together, our results indicate that combinations of abiotic and biotic factors that vary across elevation gradients are important determinants of tree turnover and productivity in the Andes. More extensive and longer-term monitoring and analyses of forest dynamics in permanent plots will be necessary to understand how demographic processes and woody biomass are responding to changing environmental conditions along elevation gradients through this century

Evenness mediates the global relationship between forest productivity and richness

1. Biodiversity is an important component of natural ecosystems, with higher species richness often correlating with an increase in ecosystem productivity. Yet, this relationship varies substantially across environments, typically becoming less pronounced at high levels of species richness. However, species richness alone cannot reflect all important properties of a community, including community evenness, which may mediate the relationship between biodiversity and productivity. If the evenness of a community correlates negatively with richness across forests globally, then a greater number of species may not always increase overall diversity and productivity of the system. Theoretical work and local empirical studies have shown that the effect of evenness on ecosystem functioning may be especially strong at high richness levels, yet the consistency of this remains untested at a global scale. 2. Here, we used a dataset of forests from across the globe, which includes composition, biomass accumulation and net primary productivity, to explore whether productivity correlates with community evenness and richness in a way that evenness appears to buffer the effect of richness. Specifically, we evaluated whether low levels of evenness in speciose communities correlate with the attenuation of the richness–productivity relationship. 3. We found that tree species richness and evenness are negatively correlated across forests globally, with highly speciose forests typically comprising a few dominant and many rare species. Furthermore, we found that the correlation between diversity and productivity changes with evenness: at low richness, uneven communities are more productive, while at high richness, even communities are more productive. 4. Synthesis. Collectively, these results demonstrate that evenness is an integral component of the relationship between biodiversity and productivity, and that the attenuating effect of richness on forest productivity might be partly explained by low evenness in speciose communities. Productivity generally increases with species richness, until reduced evenness limits the overall increases in community diversity. Our research suggests that evenness is a fundamental component of biodiversity–ecosystem function relationships, and is of critical importance for guiding conservation and sustainable ecosystem management decisions

Native diversity buffers against severity of non-native tree invasions

Determining the drivers of non-native plant invasions is critical for managing native ecosystems and limiting the spread of invasive species$^{1,2}$. Tree invasions in particular have been relatively overlooked, even though they have the potential to transform ecosystems and economies$^{3,4}$. Here, leveraging global tree databases$^{5,6,7}$, we explore how the phylogenetic and functional diversity of native tree communities, human pressure and the environment influence the establishment of non-native tree species and the subsequent invasion severity. We find that anthropogenic factors are key to predicting whether a location is invaded, but that invasion severity is underpinned by native diversity, with higher diversity predicting lower invasion severity. Temperature and precipitation emerge as strong predictors of invasion strategy, with non-native species invading successfully when they are similar to the native community in cold or dry extremes. Yet, despite the influence of these ecological forces in determining invasion strategy, we find evidence that these patterns can be obscured by human activity, with lower ecological signal in areas with higher proximity to shipping ports. Our global perspective of non-native tree invasion highlights that human drivers influence non-native tree presence, and that native phylogenetic and functional diversity have a critical role in the establishment and spread of subsequent invasions

The global biogeography of tree leaf form and habit

Understanding what controls global leaf type variation in trees is crucial for comprehending their role in terrestrial ecosystems, including carbon, water and nutrient dynamics. Yet our understanding of the factors influencing forest leaf types remains incomplete, leaving us uncertain about the global proportions of needle-leaved, broadleaved, evergreen and deciduous trees. To address these gaps, we conducted a global, ground-sourced assessment of forest leaf-type variation by integrating forest inventory data with comprehensive leaf form (broadleaf vs needle-leaf) and habit (evergreen vs deciduous) records. We found that global variation in leaf habit is primarily driven by isothermality and soil characteristics, while leaf form is predominantly driven by temperature. Given these relationships, we estimate that 38% of global tree individuals are needle-leaved evergreen, 29% are broadleaved evergreen, 27% are broadleaved deciduous and 5% are needle-leaved deciduous. The aboveground biomass distribution among these tree types is approximately 21% (126.4 Gt), 54% (335.7 Gt), 22% (136.2 Gt) and 3% (18.7 Gt), respectively. We further project that, depending on future emissions pathways, 17-34% of forested areas will experience climate conditions by the end of the century that currently support a different forest type, highlighting the intensification of climatic stress on existing forests. By quantifying the distribution of tree leaf types and their corresponding biomass, and identifying regions where climate change will exert greatest pressure on current leaf types, our results can help improve predictions of future terrestrial ecosystem functioning and carbon cycling