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5 resultados encontrados para: AUTOR: Bonnell, Tyler R.
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1.
- Artículo con arbitraje
*Solicítelo con su bibliotecario/a
Primates adjust movement strategies due to changing food availability
Reyna Hurtado, Rafael Ángel (autor) ; Teichroeb, Julie A. (autora) ; Bonnell, Tyler R. (autor) ; Hernández Sarabia, Raúl Uriel (autor) ; Vickers, Sofia M. (autora) ; Serio Silva, Juan Carlos (autor) ; Sicotte, Pascale (autora) ; Chapman, Colin A. (autor) ;
Disponible en línea
Contenido en: Behavioral Ecology Behavioral Ecology Vol. 29, no. 2 (March-April 2018), p. 368–376 ISSN: 1465-7279
Nota: Solicítelo con su bibliotecario/a
Resumen en: Inglés |
Resumen en inglés

Animals are hypothesized to search their environments in predictable ways depending on the distribution of resources. Evenly distributed foods are thought to be best exploited with random Brownian movements; while foods that are patchy or unevenly distributed require non-Brownian strategies, such as Lévy walks. Thus, when food distribution changes due to seasonal variation, animals should show concomitant changes in their search strategies. We examined this issue in 6 monkey species from Africa and Mexico: 3 frugivores and 3 folivores. We hypothesized that the more patchily distributed fruit would result in frugivores showing more levy-like patterns of motion, while folivores, with their more homogenous food supply, would show Brownian patterns of motion. At least 3 and up to 5 of 6 species conformed to the overall movement pattern predicted by their primary dietary item. For folivorous black howler monkeys (Alouatta pigra), ursine colobus (Colobus vellerosus), and red colobus (Procolobus rufomitratus), Brownian movement was supported or could not be ruled-out. Two frugivores (spider monkeys, Ateles geoffroyi yucatanensis, and gray-cheeked mangabeys, Lophocebus albigena) showed Lévy walks, as predicted, but frugivorous vervet monkeys (Chlorocebus pygerythrus) showed a Brownian walk. Additionally, we test whether seasonal variation in the spatial availability of food support environmentally driven changes in movement patterns. Four of 5 species tested for seasonal variation showed adjustments in their search strategies between the rainy and dry seasons. This study provides support for the notion that food distribution determines search strategies and that animal movement patterns are flexible, mirroring changes in the environment.


Resumen en español

La vida en grupos en ungulados ha evolucionado principalmente en especies que viven en áreas abiertas, tales como sabanas y pastizales, mientras que solamente algunas especies de ungulados que viven en bosques forman grupos, y estos tienden a ser pequeños. Por esta razón, el pecarí de labios blancos (Tayassu pecari), un ungulado Neotropical clasificado como Vulnerable por la UICN, representa una fenómeno social único, ya que vive en grandes grupos cohesivos, a pesar de habitar bosques tropicales densos. Se han observado grandes variaciones en los tamaños de grupo en su distribución, con reportes de manadas que varían de menos de 10 a más de 300 individuos. En este estudio examinamos los factores que pueden estar causando esta variación, incluyendo variables ecológicas y antropogénicas. Hicimos una revisión exhaustiva de la literatura y usamos nuestros datos originales para compilar información de tamaños de grupo a lo largo de su rango. Construimos modelos estadísticos para cuantificar generalizaciones para tamaños de grupos distinguiendo datos de áreas con alta presión humana (i.e. cacería) y áreas que no han recibido presión humana importante en por al menos 20 años. Encontramos que los tamaños de grupos son afectados por una combinación de la distancia al asentamiento humano más cercano y la cantidad de lluvia y su estacionalidad. Los resultados de los sitios con poca presión humana indican que los grupos más grandes se encuentran en áreas con mayor precipitación. Nuestros resultados contribuyen a entender porque los tamaños de grupo varían en diferentes ambientes que están sujetos a diferentes condiciones ecológicas y humanas. La información de estas relaciones es clave para avanzar en nuestro conocimiento de las estrategias socio-ecológicas de especies que viven en grupos.

Resumen en inglés

Group living among ungulates has evolved mainly in species living in open habitats, such as grasslands and savannas, whereas in the forest, few ungulate species form groups and these tend to be small. Therefore, the white-lipped peccary (Tayassu pecari), a Neotropical ungulate listed as Vulnerable by the IUCN, represents an almost unique social occurrence as it lives in large and cohesive groups, yet it inhabits dense tropical forests. Large variations in group sizes have been observed throughout the species range, with reports of herds with less than 10 to around 300 individuals. We examined factors that might cause variation in group size in white-lipped peccary, including ecological and anthropogenic variables. We conducted an extensive literature review and used our original data to compile information on white-lipped peccary's group size across its range. We built models to quantitate generalizations for group sizes distinguishing data from areas with high human influence, and areas that have not been significantly disturbed by humans for at least the last 20 years. We found that white-lipped peccary's group size for all sites was most strongly predicted by a combination of the distances to the nearest human settlement and rainfall and its seasonality. Results from the undisturbed sites indicated that group size is positively influenced by rainfall. Our results contribute to understand why group size varies in different environments that are subjected to different ecological and human conditions. Information on these relationships is a key to advance our understanding of the socio-ecological strategies of animal species living in groups.


3.
- Artículo con arbitraje
Competing pressures on populations: long-term dynamics of food availability, food quality, disease, stress and animal abundance
Chapman, Colin A. ; Schoof, Valérie A. M. (coaut.) ; Bonnell, Tyler R. (coaut.) ; Gogarten, Jan F. (coaut.) ; Calmé, Sophie (coaut.) ;
Contenido en: Philosophical Transactions of the Royal Society B. Biological Sciences Vol. 370, no. 1669 (May 2015), p. 1-9 ISSN: 1471-2970
Resumen en: Inglés |
Resumen en inglés

Despite strong links between sociality and fitness that ultimately affect the size of animal populations, the particular social and ecological factors that lead to endangerment are not well understood. Here, we synthesize approximately 25 years of data and present new analyses that highlight dynamics in forest composition, food availability, the nutritional quality of food, disease, physiological stress and population size of endangered folivorous red colobus monkeys (Procolobus rufomitratus). There is a decline in the quality of leaves 15 and 30 years following two previous studies in an undisturbed area of forest. The consumption of a low-quality diet in one month was associated with higher glucocorticoid levels in the subsequent month and stress levels in groups living in degraded forest fragments where diet was poor was more than twice those in forest groups. In contrast, forest composition has changed and when red colobus food availability was weighted by the protein-to-fibre ratio, which we have shown positively predicts folivore biomass, there was an increase in the availability of high-quality trees. Despite these changing social and ecological factors, the abundance of red colobus has remained stable, possibly through a combination of increasing group size and behavioural flexibility.


4.
- Artículo con arbitraje
Analysing small-scale aggregation in animal visits in space and time: the ST-BBD method
Bonnell, Tyler R. ; Dutilleul, Pierre (coaut.) ; Chapman, Colin A. (coaut.) ; Reyna Hurtado, Rafael Ángel (coaut.) ; Hernández Sarabia, Raul Uriel (coaut.) ; Sengupta, Raja (coaut.) ;
Contenido en: Animal Behaviour Vol. 85, no. 2 (February 2013), p. 483–492 ISSN: 0003-3472
Resumen en: Inglés |
Resumen en inglés

Movement behaviour plays an important role in many ecological interactions. As animals move through the environment, they generate movement patterns, which are a combined result of landscape characteristics and species-specific behaviour. Measuring these ranging patterns is being facilitated by technological advances in collection methods, such as GPS collars, that are capturing movement on finer spatial and temporal scales. We propose the use of a novel spatiotemporal analytical framework (ST-BBD), based on the beta-binomial distribution (BBD) model, to measure small-scale aggregation in animal movement data sets, including two simulated and three collected primate data sets. We use this approach to distinguish different habitat uses of three primate species (red colobus, Procolobus rufomitratus, black howler, Alouatta pigra, and spider monkey, Ateles geoffroyi) and quantify their specific use of the landscape in space and in time, using a parameter of the BBD that measures the variation in sites visited on a landscape. We found that estimates of aggregation in habitat use were higher in the frugivorous spider monkey, compared to the more folivorous howler monkey, and that in the red colobus, aggregation in site visits was dependent on group size and food availability. Applications of this framework to animal movement data could be useful in understanding ecological systems where habitat use is an important factor, such as the relationships between hosts and parasites, or parent plants and seed dispersers.


5.
- Artículo con arbitraje
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Resumen en: Inglés |
Resumen en inglés

The foraging activity of many organisms reveal strategic movement patterns, showing efficient use of spatially distributed resources. The underlying mechanisms behind these movement patterns, such as the use of spatial memory, are topics of considerable debate. To augment existing evidence of spatial memory use in primates, we generated movement patterns from simulated primate agents with simple sensory and behavioral capabilities. We developed agents representing various hypotheses of memory use, and compared the movement patterns of simulated groups to those of an observed group of red colobus monkeys (Procolobus rufomitratus), testing for: the effects of memory type (Euclidian or landmark based), amount of memory retention, and the effects of social rules in making foraging choices at the scale of the group (independent or leader led). Our results indicate that red colobus movement patterns fit best with simulated groups that have landmark based memory and a follow the leader foraging strategy. Comparisons between simulated agents revealed that social rules had the greatest impact on a group’s step length, whereas the type of memory had the highest impact on a group’s path tortuosity and cohesion. Using simulation studies as experimental trials to test theories of spatial memory use allows the development of insight into the behavioral mechanisms behind animal movement, developing case-specific results, as well as general results informing how changes to perception and behavior influence movement patterns.