165 research outputs found

    Global Geographic Patterns of Heterospecific Pollen Receipt Help Uncover Potential Ecological and Evolutionary Impacts Across Plant Communities Worldwide

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    Species interactions are known to be key in driving patterns of biodiversity across the globe. Plant-plant interactions through heterospecific pollen (HP) transfer by their shared pollinators is common and has consequences for plant reproductive success and floral evolution, and thus has the potential to influence global patterns of biodiversity and plant community assembly. The literature on HP transfer is growing and it is therefore timely to review patterns and causes of among-species variation in HP receipt at a global scale, thus uncovering its potential contribution to global patterns of biodiversity. Here we analyzed published data on 245 species distributed across five continents to evaluate latitudinal and altitudinal patterns of HP receipt. We further analyzed the role of floral symmetry and evolutionary history in mediating patterns of HP receipt. Latitude and elevation affected the likelihood and intensity of HP receipt indicating that HP transfer increases in species-rich communities and in areas with high abundance of vertebrate pollinators. Floral symmetry and evolutionary history determined HP load size across plant communities worldwide. Overall, our results suggest that HP receipt may have the potential to contribute to global geographic patterns of plant diversity by imposing strong selective pressures in species-rich areas across the globe

    The Role of Alien Species on Plant-Floral Visitor Network Structure in Invaded Communities

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    This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The interactions between pairs of native and alien plants via shared use of pollinators have been widely studied. Community level studies however, are necessary in order to fully understand the factors and mechanisms that facilitate successful plant invasion, but these are still scarce. Specifically, few community level studies have considered how differences in invasion level (alien flower abundance), and degree of floral trait similarity between native and invasive species, mediate effects on native plant-pollinator communities. Here, we evaluated the role of alien species on overall plant-floral visitor network structure, and on species-level network parameters, across nine invaded coastal communities distributed along 205 km in Yucatán, México that vary in alien species richness and flower abundance. We further assessed the potential the role of alien plant species on plant-floral visitor network structure and robustness via computational simulation of native and invasive plant extinction scenarios. We did not find significant differences between native and alien species in their functional floral phenotypes or in their visitation rate and pollinator community composition in these invaded sites. Variation in the proportion of alien plant species and flower abundance across sites did not influence plant-pollinator network structure. Species-level network parameters (i.e., normalized degree and nestedness contribution) did not differ between native and alien species. Furthermore, our simulation analyses revealed that alien species are functionally equivalent to native species and contribute equally to network structure and robustness. Overall, our results suggest that high levels of floral trait similarity and pollinator use overlap may help facilitate the integration of alien species into native plant-pollinator networks. As a result, alien species may also play a similar role than that of natives in the structure and stability of native plant and pollinator communities in the studied coastal sand dune ecosystem

    Técnicas bibliométricas para la autoevaluación de los grupos de investigación de la Universidad Autónoma de Yucatán, México

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    En este trabajo se presenta la metodología empleada en la autoevaluación de los Cuerpos Académicos del Campus de Ciencias Biológicas y Agropecuarias de la Universidad Autónoma de Yucatán, México, a través de parámetros cuantitativos que permitieron visualizar la calidad y cantidad de la producción académica. Para llevar a cabo dicha autoevaluación se empleó información bibliométrica obtenida de la base de datos Scopus©, del período enero 2000 a julio 2016. Se concluye que la metodología propuesta en este estudio puede ser útil para optimizar procesos de planeación y mejora continua de los cuerpos académicos de universidades públicas de México, así como utilizar en estudios futuros la metodología cualitativa para mejorar el proceso de autoevaluación

    Is there a negative association between the content of condensed tannins, total phenols, and total tannins of tropical plant extracts and in vitro anthelmintic activity against Haemonchus contortus eggs?

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    In vitro studies using plant extracts suggest a relationship between their polyphenol contents and their anthelmintic (AH) activity against Haemonchus contortus. High polyphenol content appears to increase the efficacy of plant extracts against H. contortus as assessed by the larval exsheathment inhibition assay (LEIA) while appearing to reduce the AH efficacy measured using the egg hatch assay (EHA). In addition, some plants lack AH activity. Therefore, the present study investigated the relationship between the contents of condensed tannins (CT), total phenols (TP), and total tannins (TT) in methanol:water extracts (70:30) obtained from ten tropical plant species consumed by small ruminants as well as their AH activity against H. contortus evaluated by LEIA and EHA. Extracts of Acacia collinsii, Lysiloma latisiliquum, Havardia albicans, Senegalia gaumeri, Mimosa bahamensis, Piscidia piscipula, Acacia pennatula, Gymnopodium floribundum, Leucaena leucocephala, and Bunchosia swartziana were examined. Positive correlations were found between the effective concentration 50% (EC50) (EHA) of extracts and their CT (r = 0.6809, P < 0.05, n = 10) and TP (r = 0.9152, P < 0.05, n = 10) content, suggesting that their concentration negatively affected AH activity against eggs. Based on the LEIA, there was no significant association between the EC50 and the CT, TP, or TT of all extracts evaluated. Thus, if sheep and goats consume a complex feed mixture with high amounts of CT, TP, and TT, it might be difficult to observe an AH effect against H. contortus egg hatching. However, the AH effect upon L3 establishment might be feasible

    Acuerdo de veda de agua superficial en la cuenca del río Balsas, repercusiones y alternativas para el desarrollo de la cuenca

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    Tesis (Maestro en ciencias del agua - gestión integral del agua de cuencas y acuíferos). Instituto Mexicano de Tecnología del Agua. Programa de PosgradoTutor: Sergio Vargas Velázquez
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