1,721,030 research outputs found
Effects of zoochory on the spatial genetic structure of plant populations
No full textDeutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/50110000165
Vertical stratification of seed‐dispersing vertebrate communities and their interactions with plants in tropical forests
No full textGene Flow and Vertical Stratification of Pollination in the Bat‐Pollinated Liana Marcgravia longifolia
No full textABSTRACT Pollen dispersal is a key driver of gene flow in plant populations, shaping their spatial genetic structure (SGS). In tropical forests, plant‐pollinator interactions vary across vertical strata due to differences in microclimate, resource availability, and foraging behavior. Bats are an important tropical pollinator group and have been observed to exhibit vertical stratification in their foraging activity, with interaction frequencies differing across forest layers. They are highly mobile and expected to transport pollen over long distances; however, their actual contribution to gene flow has rarely been investigated. Marcgravia longifolia , a bat‐pollinated Neotropical liana, offers a unique system for studying gene flow across forest strata. Unlike most other plant species, M. longifolia produces flowers from the forest floor to the canopy, allowing us to study how bat pollination differs across strata. This study examines pollen dispersal distances, the vertical stratification of gene flow, and SGS in M. longifolia at a 100 ha study site in western Amazonia. Pollen dispersal distances were up to 1350 m, with longer distances observed in the understory and midstory, where bat foraging activity is more frequent. We detected no SGS, suggesting extensive gene flow facilitated by bat pollination across forest strata. These findings underscore the critical role of bats in shaping plant genetic structure and demonstrate how vertical forest stratification influences gene flow in tropical ecosystems.RESUMEN La dispersión del polen es un factor clave del flujo génico en las poblaciones de plantas, dando forma a su estructura genética espacial (SGS). En los bosques tropicales, las interacciones planta‐polinizador varían a lo largo de los estratos verticales debido a diferencias en el microclima, la disponibilidad de recursos y el comportamiento de forrajeo. Los murciélagos son un grupo de polinizadores importante en los trópicos y se ha observado que presentan una estratificación vertical en su actividad de forrajeo, con frecuencias de interacción que difieren entre los distintos estratos del bosque. Son altamente móviles y se espera que transporten polen a largas distancias; aunque su contribución real al flujo génico ha sido raramente investigada. Marcgravia longifolia , una liana neotropical polinizada por murciélagos, ofrece un sistema único para estudiar el flujo génico a través de los estratos del bosque. A diferencia de la mayoría de las especies de plantas, M. longifolia produce flores desde el suelo del bosque hasta el dosel, lo que permite estudiar cómo varía la polinización por murciélagos en los distintos niveles. Este estudio examina las distancias de dispersión del polen, la estratificación vertical del flujo génico y la SGS en M. longifolia en un sitio de estudio de 100 hectáreas en la Amazonía occidental. Las distancias de dispersión del polen alcanzaron hasta 1350 metros, observándose distancias mayores en el sotobosque y el estrato medio, donde la actividad de forrajeo de los murciélagos es más frecuente. No se detectó SGS, lo que sugiere un flujo génico extenso facilitado por la polinización por murciélagos a través de los estratos del bosque. Estos resultados destacan el papel crucial de los murciélagos en la formación de la estructura genética de las plantas y demuestran cómo la estratificación vertical de los bosques influye en el flujo génico en los ecosistemas tropicales.ABSTRACT Pollen dispersal is a key driver of gene flow in plant populations, shaping their spatial genetic structure (SGS). In tropical forests, plant‐pollinator interactions vary across vertical strata due to differences in microclimate, resource availability, and foraging behavior. Bats are an important tropical pollinator group and have been observed to exhibit vertical stratification in their foraging activity, with interaction frequencies differing across forest layers. They are highly mobile and expected to transport pollen over long distances; however, their actual contribution to gene flow has rarely been investigated. Marcgravia longifolia , a bat‐pollinated Neotropical liana, offers a unique system for studying gene flow across forest strata. Unlike most other plant species, M. longifolia produces flowers from the forest floor to the canopy, allowing us to study how bat pollination differs across strata. This study examines pollen dispersal distances, the vertical stratification of gene flow, and SGS in M. longifolia at a 100 ha study site in western Amazonia. Pollen dispersal distances were up to 1350 m, with longer distances observed in the understory and midstory, where bat foraging activity is more frequent. We detected no SGS, suggesting extensive gene flow facilitated by bat pollination across forest strata. These findings underscore the critical role of bats in shaping plant genetic structure and demonstrate how vertical forest stratification influences gene flow in tropical ecosystems.RESUMEN La dispersión del polen es un factor clave del flujo génico en las poblaciones de plantas, dando forma a su estructura genética espacial (SGS). En los bosques tropicales, las interacciones planta‐polinizador varían a lo largo de los estratos verticales debido a diferencias en el microclima, la disponibilidad de recursos y el comportamiento de forrajeo. Los murciélagos son un grupo de polinizadores importante en los trópicos y se ha observado que presentan una estratificación vertical en su actividad de forrajeo, con frecuencias de interacción que difieren entre los distintos estratos del bosque. Son altamente móviles y se espera que transporten polen a largas distancias; aunque su contribución real al flujo génico ha sido raramente investigada. Marcgravia longifolia , una liana neotropical polinizada por murciélagos, ofrece un sistema único para estudiar el flujo génico a través de los estratos del bosque. A diferencia de la mayoría de las especies de plantas, M. longifolia produce flores desde el suelo del bosque hasta el dosel, lo que permite estudiar cómo varía la polinización por murciélagos en los distintos niveles. Este estudio examina las distancias de dispersión del polen, la estratificación vertical del flujo génico y la SGS en M. longifolia en un sitio de estudio de 100 hectáreas en la Amazonía occidental. Las distancias de dispersión del polen alcanzaron hasta 1350 metros, observándose distancias mayores en el sotobosque y el estrato medio, donde la actividad de forrajeo de los murciélagos es más frecuente. No se detectó SGS, lo que sugiere un flujo génico extenso facilitado por la polinización por murciélagos a través de los estratos del bosque. Estos resultados destacan el papel crucial de los murciélagos en la formación de la estructura genética de las plantas y demuestran cómo la estratificación vertical de los bosques influye en el flujo génico en los ecosistemas tropicales.Deutsche Forschungsgemeinschaft https://doi.org/10.13039/501100001659Eva Mayr-Stihl Stiftung https://doi.org/10.13039/50110002280
Feeding ecology of monk sakis (Pithecia monachus) in a seasonally flooded forest in western Amazonia
Full text linkSakis (genus Pithecia) are frugivorous primates with a preference for seeds that complete their diet with leaves and insects. Fruit pulp and seeds are known to have different nutritional characteristics that change during the process of ripening. The consumption of seeds can be an adaptation to changes in resource availability, as unripe seeds are a more steadily available resource than ripe pulp or young leaves. Here, we present the first study of the feeding ecology of monk sakis (Pithecia monachus). We investigated dietary composition and identified important feeding plants in a seasonally flooded forest within the Área de Conservación Regional Comunal Tamshiyacu-Tahuayo in Peruvian Amazonia. Throughout 20 months, we followed groups of monk sakis by foot and canoe and recorded 459 feeding events. Seeds were the most frequently consumed food item (49%), followed by pulp (mesocarp, pericarp or aril; 25%) and arthropods (22%). Leaves, bark, and flowers were ingested only sporadically. The importance of ripe seeds and arthropods in the diet of the monk sakis differed from other studies: we recorded the consumption of mostly ripe seeds and the share of arthropods was relatively high
Author Correction: Small Neotropical primates promote the natural regeneration of anthropogenically disturbed areas
No full textAn amendment to this paper has been published and can be accessed via a link at the top of the paper
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Vergleich von Trap-Nests aus Schilf mit standardisierten Nistblöcken aus Holz und MDF zur Erfassung hohlraumnistender Hymenopteren und deren natürlichen Gegenspielern
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