Papers by Raúl Ortiz Pulido
Huitzil Revista Mexicana de Ornitología
El trastorno de la queratina aviar ocasiona un crecimiento anormal del pico y afecta a varias esp... more El trastorno de la queratina aviar ocasiona un crecimiento anormal del pico y afecta a varias especies de aves en América y Europa. Sin embargo, hasta la fecha, no se había registrado en el grupo de los colibríes. En este trabajo reportamos a un individuo de Hylocharis leucotis con dicho trastorno, el cual fue capturado en la localidad de San Bernardino Lagunas, Vicente Guerrero, Puebla. Es posible que esta alteración afecte la alimentación y polinización de los colibríes que la padecen.
Hummingbird-plant mutualistic networks: comparison at two spatial scales.-Mutualistic interaction... more Hummingbird-plant mutualistic networks: comparison at two spatial scales.-Mutualistic interactions are the functional basis of ecological communities. One of the most important mutualistic interactions is pollination, such as between hummingbirds (Trochilidae) and many plant species. The hummingbird-plant interactions can be better understood by the use of mutualistic networks approach. Through this approach we can define, for example, key species of a community and the effect that its extinction can cause in such community. Despite of its ecological importance, several aspects of hummingbird-plant mutualistic networks are unknown, e.g., if key species are similar between different spatial scales. In this paper, we determined at two spatial scales (landscape and vegetation type) the degree of specialization of such networks, and dependence and asymmetry of interacting species of hummingbird-plant mutualistic networks at Metztitlan Ravine Biosphere Reserve, Mexico. During one year of systematic sampling, we recorded eight hummingbird species and 27 species of plants visited by them at landscape level. The degree of specialization as well as the values of dependence and asymmetry indicate that each vegetation type has different key species, and that some of these species are key species at landscape level, too. Cynanthus latirostris and Hylocharis leucotis were the key hummingbirds species at landscape level, while C. latirostris and Calothorax lucifer were key species for Submontane Scrub and H. leucotis for Oak Forest and Pine-Oak Forest. The key plant species at landscape level were Pachycereus marginatus and Salvia Mexicana while P. marginatus was important for Submontane Scrub, Cirsium ehrembergii for Pine-Oak Forest, and S. mexicana and S. microphylla were important for Oak forest. Our results suggest that the spatial level of analysis determines the identity of the key species in hummingbird-plant mutualistic networks, which must be taken into account when aiming at the conservation of such networks in a landscape. Resumen.-Las interacciones mutualistas son la base del funcionamiento de las comunidades ecológicas. Una de las interacciones mutualistas más importantes es la polinización, como la realizada por colibríes (Trochilidae) en diferentes especies de plantas. Las interacciones colibrí-planta pueden ser entendidas mejor si se usa la aproximación de redes mutualistas. A través de esta aproximación se pueden definir, por ejemplo, las especies claves en una comunidad mutualista y el efecto que tendría en la comunidad su extinción. A pesar de su importancia, se desconocen muchos aspectos de las redes mutualistas colibrí-planta, por ejemplo: si las especies clave son semejantes entre diferentes escalas espaciales. En este trabajo determinamos, en dos escalas espaciales (paisaje y tipo de vegetación), el grado de especialización de las redes, la dependencia y la asimetría de las especies participantes en redes mutualistas planta
Amphibian species of the family Hylidae exhibit a high degree of endemism in Mexico. To better un... more Amphibian species of the family Hylidae exhibit a high degree of endemism in Mexico. To better understand ongoing declines of many amphibian populations, especially for endemic species that are particularly vulnerable to extinction, information on diverse aspects of their biological makeup is required, including their ecology. This study provides an analysis of the distribution, natural history, feeding habits, reproduction, morphology, and conservation status of Charadrahyla taeniopus, a species endemic to central Mexico. The distribution of this species extends along the Sierra Madre Oriental, primarily in cloud forest. Based on changes in climatic niche, decreases of 14.14% and 37% of its distributional range are predicted to occur by the years 2050 and 2070, respectively. An examination of the stomach contents from 31 adults and two juveniles revealed plant materials and arthropods as major parts of their diet. Charadrahyla taeniopus is sexually dimorphic in size. Females were larger than males, and after correcting for body size, females had larger jaws than males. Based on guidelines proposed by national legislation (NOM-059), we propose that this species should continue to be classified as Threatened. Further studies are necessary to classify it in a high conservation category by international legislation (IUCN) guidelines, due to the high vulnerability indicated by the Environmental Vulnerability Score, which is caused by an accelerated loss of habitat. Charadrahyla taeniopus is a good model for analyzing the conservation status of hylid frogs from temperate areas and in highly transformed environments, as this species exemplifies the conservation status of endemic amphibians in central Mexico.
Trying to unravel Darwin's entangled bank further, we describe the architecture of a network ... more Trying to unravel Darwin's entangled bank further, we describe the architecture of a network involving multiple forms of mutualism (pollination by animals, seed-dispersal by birds and plant protection by ants) and evaluated whether this multi-network shows evidence of a structure that promotes robustness. We found that species differed strongly in their contributions to the organization of the multi-interaction network, and that only a few species contributed to the structuring of these patterns in the multi-interaction network. Moreover, we observed that the multi-interaction networks did not enhance community robustness compared with each of the three independent mutualistic networks when analysed across a range of simulated scenarios of species extinction. By simulating the removal of highly interacting species, we observed that, overall, these species contribute to enhance network nestedness and robustness, but decrease modularity. We discuss how the organization of interlinked mutualistic networks may be essential for the maintenance of ecological communities, and therefore, the long-term ecological and evolutionary dynamics of interactive, species-rich communities. Therefore, we suggest that conserving these keystone mutualists and their interactions is crucial to the persistence of species-rich mutualistic assemblages, mainly because they support other species and shape the network organization.
In mutualistic networks, interactions between species are constrained by an array of ecological m... more In mutualistic networks, interactions between species are constrained by an array of ecological mechanisms, such as morphological matching, phenological overlap and species’ abundances. It remains poorly understood how these mechanisms change in ability to explain interaction frequencies across environmental gradients. Consequently, there is also limited knowledge on how the mechanisms affect geographical patterns in network structure, such as resource specialization. Here, we investigated the degree to which morphological matching, phenological overlap and species’ abundances explain interactions between hummingbirds and plants. For 24 quantitative networks sampled across the Americas, we found an increased tendency for species to interact with morphologically matching partners towards low latitudes and areas with low temperature seasonality. Moreover, species’ morphologies and phenologies generally performed better than abundance at explaining interaction frequencies. However, onl...
Functional Ecology, 2021
This is the author manuscript accepted for publication and has undergone full peer review but has... more This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as
Herreriana, 2021
A través de una historia de ciencia ficción se describe brevemente el uso que podría tener el mot... more A través de una historia de ciencia ficción se describe brevemente el uso que podría tener el motor Alcubierre para la conquista del espacio. De la misma manera se plantean algunas implicaciones que tiene hacer uso de la tecnología sin considerar aspectos éticos.
Herreriana, 2020
Greta Thunberg es una activista ambiental de 16 años que ha denunciado internacionalmente el efec... more Greta Thunberg es una activista ambiental de 16 años que ha denunciado internacionalmente el efecto que podría tener el cambio climático global en la humanidad. Por ello ella ha sido tachada de ser una enferma mental, una marioneta y una niña rica y catastrofista. En este trabajo evaluamos la veracidad de cinco de sus afirmaciones hechas en un foro mundial ¿Sus detractores tienen razón? o ¿Greta dice verdades incómodas para ciertos intereses económicos y políticos? Te invitamos a acompañarnos en nuestra búsqueda de la verdad.
Revista Internacional de Medicina y Ciencias de la Actividad Física y del Deporte, 2018
El objetivo de este estudio fue determinar si existen diferencias en los valores de VO2max indire... more El objetivo de este estudio fue determinar si existen diferencias en los valores de VO2max indirecto obtenido con cinco pruebas físicas: UTMM, VAM-EVAL, Ida-Vuelta, 1000 m y Ramsbottom. Los sujetos fueron hombres mexicanos en edad universitaria sin entrenamiento previo y sin experiencia en deportes, con los siguientes parámetros:
Proceedings of the Royal Society B: Biological Sciences, 2020
Interactions between species are influenced by different ecological mechanisms, such as morpholog... more Interactions between species are influenced by different ecological mechanisms, such as morphological matching, phenological overlap and species abundances. How these mechanisms explain interaction frequencies across environmental gradients remains poorly understood. Consequently, we also know little about the mechanisms that drive the geographical patterns in network structure, such as complementary specialization and modularity. Here, we use data on morphologies, phenologies and abundances to explain interaction frequencies between hummingbirds and plants at a large geographical scale. For 24 quantitative networks sampled throughout the Americas, we found that the tendency of species to interact with morphologically matching partners contributed to specialized and modular network structures. Morphological matching best explained interaction frequencies in networks found closer to the equator and in areas with low-temperature seasonality. When comparing the three ecological mechani...
Huitzil, Revista Mexicana de Ornitología, 2020
Para el bosque mesófilo de montaña en México se ha sugerido la presencia de 125 especies de aves ... more Para el bosque mesófilo de montaña en México se ha sugerido la presencia de 125 especies de aves que se encuentran en riesgo o son endémicas. Esas aves requieren ser conservadas. En un tiempo de defaunación mundial, y de reducción de estos bosques, es importante determinar qué especies de aves aún habitan en este ecosistema. Del bosque mesófilo localizado en la Sierra Madre Oriental de México no se han publicado datos recientes de campo que indiquen su presencia. En este análisis reportamos los registros de especies de aves en riesgo realizados en 2016 en cinco Áreas Importantes para la Conservación de las Aves con bosque mesófilo de montaña (Sierra Gorda, Tlanchinol, Huayacocotla, Cuetzalan y Río Metlac) ubicadas en cuatro estados de México (Querétaro, Hidalgo, Veracruz y Puebla). En total registramos 60 especies de aves (48%) de las 125, 29 son consideradas amenazadas a nivel nacional y 34 presentan algún tipo de endemismo. Seis de las especies están protegidas globalmente (Dendro...
Global Ecology and Biogeography, 2018
(USNM), Till Töpfer and Karl-Ludwig Schuchmann (ZFMK) and Jon Fjeldså (ZMSNM) for allowing the hu... more (USNM), Till Töpfer and Karl-Ludwig Schuchmann (ZFMK) and Jon Fjeldså (ZMSNM) for allowing the hummingbirds measurements in the museums and Louis Hansen for help in gathering hummingbird weight data.
Proceedings. Biological sciences, Jan 11, 2017
Cite this article: Dáttilo W et al. 2017 Correction to 'Unravelling Darwin's entangled bank: arch... more Cite this article: Dáttilo W et al. 2017 Correction to 'Unravelling Darwin's entangled bank: architecture and robustness of mutualistic networks with multiple interaction types'.
Proceedings. Biological sciences, Nov 30, 2016
Trying to unravel Darwin's entangled bank further, we describe the architecture of a network ... more Trying to unravel Darwin's entangled bank further, we describe the architecture of a network involving multiple forms of mutualism (pollination by animals, seed dispersal by birds and plant protection by ants) and evaluate whether this multi-network shows evidence of a structure that promotes robustness. We found that species differed strongly in their contributions to the organization of the multi-interaction network, and that only a few species contributed to the structuring of these patterns. Moreover, we observed that the multi-interaction networks did not enhance community robustness compared with each of the three independent mutualistic networks when analysed across a range of simulated scenarios of species extinction. By simulating the removal of highly interacting species, we observed that, overall, these species enhance network nestedness and robustness, but decrease modularity. We discuss how the organization of interlinked mutualistic networks may be essential for th...
PLOS ONE, 2016
Quantifying differences in species composition among communities provides important information r... more Quantifying differences in species composition among communities provides important information related to the distribution, conservation and management of biodiversity, especially when two components are recognized: dissimilarity due to turnover, and dissimilarity due to richness differences. The ecoregions in central Mexico, within the Mexican Transition Zone, have outstanding environmental heterogeneity and harbor huge biological richness, besides differences in the origin of the biota. Therefore, biodiversity studies in this area require the use of complementary measures to achieve appropriate information that may help in the design of conservation strategies. In this work we analyze the dissimilarity of terrestrial vertebrates, and the components of turnover and richness differences, among six ecoregions in the state of Hidalgo, central Mexico. We follow two approaches: one based on species level dissimilarity, and the second on taxonomic dissimilarity. We used databases from the project "Biodiversity in the state of Hidalgo". Our results indicate that species dissimilarity is higher than taxonomic dissimilarity, and that turnover contributes more than richness differences, both for species and taxonomic total dissimilarity. Moreover, total dissimilarity, turnover dissimilarity and the dissimilarity due to richness differences were positively related in the four vertebrate groups. Reptiles had the highest values of dissimilarity, followed by mammals, amphibians and birds. For reptiles, birds, and mammals, species turnover was the most important component, while richness differences had a higher contribution for amphibians. The highest values of dissimilarity occurred between environmentally contrasting ecoregions (i.e., tropical and temperate forests), which suggests that environmental heterogeneity and differences in the origin of biotas are key factors driving beta diversity of terrestrial vertebrates among ecoregions in this complex area.
Current Zoology, 2011
Spatial and temporal variation in interactions between hummingbirds and plants have often been ex... more Spatial and temporal variation in interactions between hummingbirds and plants have often been examined, and hummingbirds and insects are known to indirectly interact in networks of nectar plants. In a highland temperate forest in Hidalgo, Mexico some oak trees were heavily infested by honeydew-producing insects (family Margarodidae, tribe Xylococcini, genus Strigmacoccus) and the honeydew was consumed by hummingbirds. Here using survival analysis we investigate how the honeydew produced by dense populations of these margarodids is temporally and spatially partitioned by hummingbirds. We also measured the availability and quality of honeydew exudates, and then we recorded the time until a bird visited and used such resources. Four hummingbird species consumed this resource (Atthis eloisa, Hylocharis leucotis, Colibri thalassinus and Eugenes fulgens). Data from 294 hours of observation on seven focal trees suggested temporal and spatial segregation among visiting birds according to b...
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Papers by Raúl Ortiz Pulido