Influence of continental history on the ecological specialization and macroevolutionary processes in the mammalian assemblage of South America: Differences between small and large mammals

Background: This paper tests Vrba's resource-use hypothesis, which predicts that generalist species have lower specialization and extinction rates than specialists, using the 879 species of South American mammals. We tested several predictions about this hypothesis using the biomic specialization index (BSI) for each species, which is based on its geographical range within different climate-zones. The four predictions tested are: (1) there is a high frequency of species restricted to a single biome, which henceforth are referred to as stenobiomic species, (2) certain clades are more stenobiomic than others, (3) there is a higher proportion of biomic specialists in biomes that underwent through major expansion-contraction alternation due to the glacial-interglacial cycles, (4) certain combinations of inhabited biomes occur more frequently among species than do others. Results: Our results are consistent with these predictions. (1) We found that 42 % of the species inhabit only one biome. (2) There are more generalists among species of Carnivora than in clades of herbivores. However, Artiodactyla, shows a distribution along the specialization gradient different from the one expected. (3) Biomic specialists are predominant in tropical rainforest and desert biomes. Nevertheless, we found some differences between small and large mammals in relation to these results. Stenobiomic species of micromammalian clades are more abundant in most biomes than expected by chance, while in the case of macromammalian clades stenobiomic species are more frequent than expected in tropical rainforest, tropical deciduous woodland and desert biomes only. (4) The most frequent combinations of inhabited biomes among the South American mammals are those with few biomes, i.e., the ones that suffered a higher rate of vicariance due to climatic cycles. Conclusion: Our results agree with the resource-use hypothesis and, therefore, with a major role of the past climatic changes as drivers of mammalian evolution. Nevertheless, deviations from the expectations indicate the importance of differences in reproductive traits and paleobiogeographic history for the macroevolutionary processes involved. In the case of South American mammals, the Pliocene Great American Biotic Interchange strongly influences the ecological characteristics of this assemblage. Furthermore, the Andes have acted as a fertile ground for speciation in environments prone to vicariance. Finally, the micromammals appear as more prone to biomic specialization than larger species. These factors are responsible for some of the differences found between South America and Africa in the studied pattern. For example, the extensive South American mountain ranges favour a higher number of combinations of inhabited biomes in comparison with Africa

Influence of continental history on the ecological specialization and macroevolutionary processes in the mammalian assemblage of South America: differences between small and large mammals

Background. This paper tests Vrba's resource-use hypothesis, which predicts that generalist species have lower specialization and extinction rates than specialists, using the 879 species of South American mammals. We tested several predictions about this hypothesis using the biomic specialization index (BSI) for each species, which is based on its geographical range within different climate-zones. The four predictions tested are: (1) there is a high frequency of species restricted to a single biome, which henceforth are referred to as stenobiomic species, (2) certain clades are more stenobiomic than others, (3) there is a higher proportion of biomic specialists in biomes that underwent through major expansion-contraction alternation due to the glacial-interglacial cycles, (4) certain combinations of inhabited biomes occur more frequently among species than do others. Results. Our results are consistent with these predictions. (1) We found that 42 % of the species inhabit only one biome. (2) There are more generalists among species of Carnivora than in clades of herbivores. However, Artiodactyla, shows a distribution along the specialization gradient different from the one expected. (3) Biomic specialists are predominant in tropical rainforest and desert biomes. Nevertheless, we found some differences between small and large mammals in relation to these results. Stenobiomic species of micromammalian clades are more abundant in most biomes than expected by chance, while in the case of macromammalian clades stenobiomic species are more frequent than expected in tropical rainforest, tropical deciduous woodland and desert biomes only. (4) The most frequent combinations of inhabited biomes among the South American mammals are those with few biomes, i.e., the ones that suffered a higher rate of vicariance due to climatic cycles. Conclusion. Our results agree with the resource-use hypothesis and, therefore, with a major role of the past climatic changes as drivers of mammalian evolution. Nevertheless, deviations from the expectations indicate the importance of differences in reproductive traits and paleobiogeographic history for the macroevolutionary processes involved. In the case of South American mammals, the Pliocene Great American Biotic Interchange strongly influences the ecological characteristics of this assemblage. Furthermore, the Andes have acted as a fertile ground for speciation in environments prone to vicariance. Finally, the micromammals appear as more prone to biomic specialization than larger species. These factors are responsible for some of the differences found between South America and Africa in the studied pattern. For example, the extensive South American mountain ranges favour a higher number of combinations of inhabited biomes in comparison with Africa.Facultad de Ciencias Naturales y Muse

Holocene climate variability, vegetation dynamics and fire regime in the central Pyrenees: the Basa de la Mora sequence (NE Spain)

High resolution multiproxy data (pollen, sedimentology, geochemistry, chironomids and charcoal) from the Basa de la Mora (BSM) lake sequence (42° 32′ N, 0° 19′ E, 1914 m a.s.l.) show marked climate variability in the central southern Pyrenees throughout the Holocene. A robust age model based on 15 AMS radiocarbon dates underpins the first precise reconstruction of rapid climate changes during the Holocene from this area. During the Early Holocene, increased winter snowpack and high snowmelt during summer, as a consequence of high seasonality, led to higher lake levels, a chironomid community dominated by non-lacustrine taxa (Orthocladiinae) related to higher inlet streams, and a forested landscape with intense run-off processes in the watershed. From 9.8 to 8.1 cal ka BP, climate instability is inferred from rapid and intense forest shifts and high fluctuation in surface run-off. Shifts among conifers and mesophytes reveal at least four short-lived dry events at 9.7, 9.3, 8.8 and 8.3 cal ka BP. Between 8.1 and 5.7 cal ka BP a stable climate with higher precipitation favoured highest lake levels and forest expansion, with spread of mesophytes, withdrawal of conifers and intensification of fires, coinciding with the Holocene Climate Optimum. At 5.7 cal ka BP a major change leading to drier conditions contributed to a regional decline in mesophytes, expansion of pines and junipers, and a significant lake level drop. Despite drier conditions, fire activity dropped as consequence of biomass reduction. Two arid intervals occurred between 2.9 and 2.4 cal ka BP and at 1.2–0.7 cal ka BP (800–1300 AD). The latter coincides with the Medieval Climate Anomaly and is one of the most arid phases of the Holocene in BSM sequence. Anthropogenic disturbances were small until 700 AD, when human pressure over landscape intensified, with Olea cultivation in the lowlands and significant deforestation in highlands. Colder and unfavourable weather conditions during the second part of the Little Ice Age caused a temporary cease of high-land management. The most intense anthropogenic disturbances occurred during the second half of 19th century. Last decades are characterized by recovery of the vegetation cover as a result of land abandonment, and lowered lake levels, probably due to higher temperatures

Famílies botàniques de plantes medicinals

Facultat de Farmàcia, Universitat de Barcelona. Ensenyament: Grau de Farmàcia, Assignatura: Botànica Farmacèutica, Curs: 2013-2014, Coordinadors: Joan Simon, Cèsar Blanché i Maria Bosch.Els materials que aquí es presenten són els recull de 175 treballs d’una família botànica d’interès medicinal realitzats de manera individual. Els treballs han estat realitzat per la totalitat dels estudiants dels grups M-2 i M-3 de l’assignatura Botànica Farmacèutica durant els mesos d’abril i maig del curs 2013-14. Tots els treballs s’han dut a terme a través de la plataforma de GoogleDocs i han estat tutoritzats pel professor de l’assignatura i revisats i finalment co-avaluats entre els propis estudiants. L’objectiu principal de l’activitat ha estat fomentar l’aprenentatge autònom i col·laboratiu en Botànica farmacèutica

Interacciones entre macroevolución y paleoecología: generalistas y especialistas en las faunas de roedores del Plio-Pleistoceno ibérico.

Existen diversas hipótesis macroevolutivas que postulan a favor de una sincronía entre los cambios climáticos y las variaciones en la estructura de las comunidades faunísticas. Estas teorías hacen evidente la importancia que puede tener el grado de especialización ecológica de un taxón. En este trabajo se evaluó la variación a lo largo del Plio-Pleistoceno ibérico de las proporciones relativas de especies de roedores generalistas respecto de las especialistas. Medimos el grado de especialización por medio del índice de especialización biómica (BSI). Fue posible poner de manifi esto la disminución de las especies especialistas debida a la perturbación climática generada por el inicio de las glaciaciones y una posterior recuperación faunística con un nuevo incremento proporcional de especialistas. [ABSTRACT] Some macroevolutionary hypotheses propose a synchrony between climatic changes and variations in the structure of faunal communities. These theories make clear the importance of the degree of ecological specialization of the taxa. In this work we evaluated the variation of the relative proportions of generalist and specialist rodents along the Iberian Plio-Pleistocene. We measured the degree of specialization using the biomic specialization index (BSI). It was possible to show the decrease of the specialist species due to the climatic perturbation generated by the onset of the glaciations, as well as the latter faunal recovery characterized by a proportional increment of specialists

Global climate changes drive ecological specialization of mammal faunas: trends in rodent assemblages from the Iberian Plio-Pleistocene

Background: Several macroevolutionary hypotheses propose a synchrony between climatic changes and variations in the structure of faunal communities. Some of them focus on the importance of the species ecological specialization because of its effects on evolutionary processes and the resultant patterns. Particularly, Vrba’s turnover pulse hypothesis and resource-use hypothesis revolve around the importance of biome inhabitation. In order to test these hypotheses, we used the Biomic Specialization Index, which is based on the number of biomes occupied by each species, and evaluated the changes in the relative importance of generalist and specialist rodents in more than forty fossil sites from the Iberian Plio-Pleistocene. Results: Our results indicate that there was a decrease in the specialization degree of rodent faunas during the Pliocene due to the global cooling that triggered the onset of the glacial events of the Cenozoic (around 2.75 Ma). The subsequent faunal transition after this critical paleoenvironmental event was characterized by an increase of specialization related to the adaptation to the new environmental conditions, which was mainly associated with the Pleistocene radiation of Arvicolinae (voles). Conclusions: The pattern of faunal turnover is correlated with the development of the modern glaciations in the Northern Hemisphere around 2.75 Ma, and represents a reorganization of the rodent communities, as suggested by the turnover pulse hypothesis. Our data also support the resource-use hypothesis, which presumes the role of the degree of specialization in resources specifically related to particular biomes as a driver of differential speciation and extinction rates. These results stress the intimate connection between ecological and evolutionary changes.We acknowledge financial support from the Spanish Ministry of Science and Innovation, through the projects CGL2006-01773/BTE and CGL2010-19116/BOS. The authors also thank the Unit of Information Resources for Research (URICI-CSIC) for the co-financing of this publication in Open Access.Peer Reviewe

Tempo and mode in the influence of global climatic changes on mammalian evolution

Comunicación presentada en: XVIII INQUA Congress, 21st–27th July, 2011, Bern, Switzerland.Due to their extraordinary fossil record during the Cenozoic, mammals are a key factor in order to understand how global climatic changes have shaped biotic evolution, especially in continental environments. During the last decades, climatic influence on the evolution of mammal faunas has been reflected mainly in two sets of studies. First, there are works focused in the use of observed variations in the structure of mammalian palaeocommunities through extensive time sequences in order to detect significant palaeoclimatic changes. These studies are based in the concepts of community convergence and uniformitarism, and make use of modern ecological analogues to infer the climatic conditions in which the extinct faunas lived. On the other hand, when data on faunal change through time are confronted with independent data on palaeoclimatic changes it may be statistically inferred whether there has been simultaneous occurrence of climatic changes, faunal turnover and modifications in the ecological structure of the palaeofaunas. The second set of studies is based on the statistical analysis of ecological data from modern faunas. Extant assemblages reflect in their ecological characteristics the past influence of global climate changes on the evolution of mammalian lineages living today, both in geographical and cladal basis. Finally, there are new works based on the study of the phylogenetic signal that can be found in modern clades, which are able to identify periods of enhanced or reduced cladogenesis. Although all these approaches cannot be used simultaneously because of latent problems derived of circular reasoning, the development of methodological protocols for the combined analysis of their results has the potential to shed new light on the question of how and when climate changes affect evolution of biotic communities.The authors also thank the Unit of Information Resources for Research (URICI-CSIC) for the co-financing of this publication in Open Access.Peer reviewe

Factores macroevolutivos en los mamíferos terrestres de América del Sur

Utilizando la información existente de toda la fauna actual de mamíferos continentales sudamericanos hemos podido probar y dar consistencia a la Hipótesis de Uso de los Recursos propuesta por Vrba, la cual predice que las especies generalistas tienen tasas de especiación y extinción más bajas que las especies especialistas. Hemos utilizado el índice de especialización biómica (BSI) de cada especie, basado en su distribución geográfica dentro de las diferentes zonas climáticas. Nuestros resultados son consistentes con las cuatro predicciones de la Hipótesis del uso de los recursos: (1) existe una elevada frecuencia de especies restringidas a un solo bioma, un 42% son especies estenobiómicas; (2) ciertos clados, como Carnivora, son más eurobiómicos que otros, como los herbívoros. Sin embargo, Artiodactyla, muestra una distribución diferente de la esperada; (3) hay una mayor número de especialistas biómicos en biomas que sufrieron con mayor fuerza los Ciclos de Milankovitch. Los especialistas biómicos son predominantes en los biomas de pluvisilva bosque tropical seco y desierto. No obstante, los micromamíferos son más propensos a la especialización biómica; (4) ciertas combinaciones biómicas aparecen con más frecuencia que otras. Las combinaciones más frecuentes son aquellas con pocos biomas, aquellos que sufrieron altas tasas de vicarianza debido a ciclos climáticos. Los resultados obtenidos apoyan la idea de que los cambios climáticos del pasado son determinantes en la evolución de los mamíferos actuales, y además las desviaciones obtenidas en el estudio proponen una mirada hacia nuevos factores como la historia paleográfica del continente y los caracteres reproductivos de las especies. [ABSTRACT] Using the extant information of the complete fauna of South American terrestrial mammals we proved the Vrba’s resource-use hypothesis, which predicts that speciation and extinction rates are lower in generalist species than specialist. We used the biomic specialization index (BSI) for each species, which is based on its geographical distribution within different climate-zones. Our results are consistent with four predictions of the resource-use hipotesis: (1) there is a high frequency of species restricted to single biomes, which henceforth are referred to as stenobiomic species; we found that 42% of the species inhabit only one biome; (2) certain clades, as Carnivora, are more euryibiomic than others. However, Artiodactyla, shows a distribution along the specialization gradient different from the one expected; (3) there is a higher proportion of biomic specialists in biomes that underwent high fragmentation during the Milankovitch Cycles. The biomic specialists are predominant in rainforest, dry tropical forest and desert biomes. Nevertheless, micromammals appear as more prone to biomic specialization than macromammals; (4) certain climatic combinations occur more frequently than do others. The most frequent combinations are those with few biomes, the ones that suffered a higher rate of vicariance due to climatic cycles. Our results support an idea defending the major role of the past climatic changes as drivers of mammalian evolution, and suggest a new view towards other factors like paleobiogeographic history and the differences in reproductive traits of the species

Impacto de los movimientos migratorios en la resistencia bacteriana a los antibióticos

Background: Spain is among the main receptor countries for immigration; but there are few studies available which target antibiotic-resistance in immigrants. Our objective was to review the current knowledge on the impact of antibiotic resistance in immigrants compared with the prevalence in the autochthonous population. Methods: A comprehensive bibliographical search was performed to detect published works in the 1998-2013 period. Common keywords were: resistance; immigrant, and Spain; particular keywords were: Mycobacterium tuberculosis, Neisseria gonorrhoeae, or Enterobacteriaceae and travellers in each topic. Results: Global percentage of resistant M. tuberculosis strains was 2.5-4 times more frequent in immigrant population than native population. The proportion of MDR strains was also higher in adult and infant immigrant populations (2,5% and 4,5% respectively) than in native population (0,1%-0% respectively). Known cases of gonorrhoea among immigrant population represented 28%, proceeding from geographical areas with high resistance to macrolide (30%) and cephalosporins (20%). This data revels the possibility of dissemination of untreatable N. gonorrhoeae strains. The detection of multidrug-resistant Enterobacteriaceae in Spaniard travellers visiting countries with high rates of antibiotic resistance was increased from 7.9% to 17.9% (even 37.4% in native travellers from India). Conclusion: The different rates of antibiotic resistance between native and immigrant populations in the studied models in this review, revealed as the migration can affect to emergence and re-emergence of infection diseases, but also the potential spreading of untreatable microorganisms.Fundamentos: España es uno de los principales aceptores mundiales de inmigrantes. Sin embargo existen escasos trabajos sobre la caracterización de bacterias resistentes en la población inmigrante en España. El objetivo es conocer el impacto de la inmigración en la prevalencia de la resistencia antibiótica en España. Métodos: Se realizó una revisión bibliográfica artículos originales publicados entre 1998-2013 realizando la búsqueda con las palabras clave resistencia, inmigrante y España más Mycobacterium tuberculosis, Neisseria gonorrhoeae o Enterobacteriaceae y diarrea del viajero para cada uno de los sub-apartados. Resultados: El porcentaje global de cepas de M. tuberculosis resistentes fue 2,5-4 veces más frecuente en la población inmigrante que en la población nativa. La proporción de cepas multiresistentes fue también mayor en población inmigrante adulta (2,5%) e infantil (4,5%) respecto a población autóctona (0,1-0%) respectivamente. El 28% de casos de gonococia en España se detectaron en inmigrantes procedentes de áreas con altos niveles de resistencia a macrólidos (30%) y cefalosporinas (20%) suponiendo un peligro de diseminación de cepas de N. gonorrhoeae de difícil tratamiento. La detección de enterobacterias multiresistentes en individuos españoles antes y después de realizar viajes a países con alta resistencia se elevó desde 7,9% a 17,9% (a 37,4% en personas procedentes de India). Conclusiones: Las diferentes tasas de resistencia entre población autóctona y población inmigrante en los modelos estudiados en esta revisión revelan que los flujos migratorios no solo afectan a la emergencia o re-emergencia de enfermedades infecciosas sino también a la elección de tratamiento efectivo