384 research outputs found
Depredació de llavors dels aladerns (Phillyrea spp.) després de la dispersió per sargantanes i ocells a l'illa de Cabrera
Insect frugivory in Juniperus phoeniceae (L.) (Cupressaceae) in Cabrera Island (Balearic Archipelago)
La desinstitucionalización y la crisis de las instituciones
.Hablar de instituciones se ha convertido en hablar de crisis de las instituciones. En este sentido, la noción de desinstitucionalización ocupa un lugar relevante en la reflexión institucional. Por este motivo, en este artÃculo se lleva a cabo una revisión del concepto de institución y de las principales crÃticas que ha recibido como paso previo al análisis más detallado del fenómeno desinstitucionalizador en la práctica psiquiátrica. Tal análisis lleva a la elaboración de una propuesta alternativa que cuestiona la pertinencia de seguir hablando de instituciones asà como de procesos desinstitucionalizadores. Concretamente, se plantea que las especiales caracterÃsticas de algunas prácticas psiquiátricas contemporáneas se ajustan mejor a la noción de ex-titución tomada de la obra de Serres
The Labile Limits of Forbidden Interactions
Forbidden links are defined as pairwise interactions that are prevented by the biological traits of the species. We focus here on the neglected importance of intraspecific trait variation in the forbidden link concept. We show how intraspecific trait variability at different spatiotemporal scales, and through ontogeny, reduces the expected prevalence of forbidden interactions. We also highlight how behavior can foster interactions that, from traits, would be predicted to be forbidden. We therefore discuss the drawbacks of frameworks recently developed to infer biotic interactions using available trait data (mean values). Mispredictions can have disproportionate effects on inferences about community dynamics. Thus, we suggest including intraspecific variability in trait-based models and using them to guide the sampling of real interactions in the field for validation
Predicting Spatial Patterns of Plant Recruitment Using Animal-Displacement Kernels
For plants dispersed by frugivores, spatial patterns of recruitment are primarily influenced by the spatial arrangement and characteristics of parent plants, the digestive characteristics, feeding behaviour and movement patterns of animal dispersers, and the structure of the habitat matrix. We used an individual-based, spatially-explicit framework to characterize seed dispersal and seedling fate in an endangered, insular plant-disperser system: the endemic shrub Daphne rodriguezii and its exclusive disperser, the endemic lizard Podarcis lilfordi. Plant recruitment kernels were chiefly determined by the disperser's patterns of space utilization (i.e. the lizard's displacement kernels), the position of the various plant individuals in relation to them, and habitat structure (vegetation cover vs. bare soil). In contrast to our expectations, seed gut-passage rate and its effects on germination, and lizard speed-of-movement, habitat choice and activity rhythm were of minor importance. Predicted plant recruitment kernels were strongly anisotropic and fine-grained, preventing their description using one-dimensional, frequency-distance curves. We found a general trade-off between recruitment probability and dispersal distance; however, optimal recruitment sites were not necessarily associated to sites of maximal adult-plant density. Conservation efforts aimed at enhancing the regeneration of endangered plant-disperser systems may gain in efficacy by manipulating the spatial distribution of dispersers (e.g. through the creation of refuges and feeding sites) to create areas favourable to plant recruitment
Macaronesia as a fruitful arena for Ecology, Evolution and Conservation Biology
peer reviewe
Beyond species loss: The extinction of ecological interactions in a changing world
© 2014 The Authors. The effects of the present biodiversity crisis have been largely focused on the loss of species. However, a missed component of biodiversity loss that often accompanies or even precedes species disappearance is the extinction of ecological interactions. Here, we propose a novel model that (i) relates the diversity of both species and interactions along a gradient of environmental deterioration and (ii) explores how the rate of loss of ecological functions, and consequently of ecosystem services, can be accelerated or restrained depending on how the rate of species loss covaries with the rate of interactions loss. We find that the loss of species and interactions are decoupled, such that ecological interactions are often lost at a higher rate. This implies that the loss of ecological interactions may occur well before species disappearance, affecting species functionality and ecosystems services at a faster rate than species extinctions. We provide a number of empirical case studies illustrating these points. Our approach emphasizes the importance of focusing on species interactions as the major biodiversity component from which the 'health' of ecosystems depends.Peer Reviewe
Fungal infestation boosts fruit aroma and fruit removal by mammals and birds
For four decades, an influential hypothesis has posited that competition for food resources between
microbes and vertebrates selects for microbes to alter these resources in ways that make them
unpalatable to vertebrates. We chose an understudied cross kingdom interaction to experimentally
evaluate the effect of fruit infection by fungi on both vertebrate (mammals and birds) fruit preferences
and on ecologically relevant fruit traits (volatile compounds, toughness, etc). Our well-replicated field
experiments revealed that, in contrast to previous studies, frugivorous mammals and birds consistently
preferred infested over intact fruits. This was concordant with the higher level of attractive volatiles
(esters, ethanol) in infested fruits. This investigation suggests that vertebrate frugivores, fleshyfruited
plants, and microbes form a tripartite interaction in which each part could interact positively
with the other two (e.g. both orange seeds and fungal spores are likely dispersed by mammals). Such
a mutualistic view of these complex interactions is opposed to the generalized idea of competition
between frugivorous vertebrates and microorganisms. Thus, this research provides a new perspective
on the widely accepted plant evolutionary dilemma to make fruits attractive to mutualistic frugivores
while unattractive to presumed antagonistic microbes that constrain seed dispersalinfo:eu-repo/semantics/publishedVersio
Predicting Invasive Fungal Pathogens Using Invasive Pest Assemblages: Testing Model Predictions in a Virtual World
Predicting future species invasions presents significant challenges to researchers and government agencies. Simply considering the vast number of potential species that could invade an area can be insurmountable. One method, recently suggested, which can analyse large datasets of invasive species simultaneously is that of a self organising map (SOM), a form of artificial neural network which can rank species by establishment likelihood. We used this method to analyse the worldwide distribution of 486 fungal pathogens and then validated the method by creating a virtual world of invasive species in which to test the SOM. This novel validation method allowed us to test SOM's ability to rank those species that can establish above those that can't. Overall, we found the SOM highly effective, having on average, a 96–98% success rate (depending on the virtual world parameters). We also found that regions with fewer species present (i.e. 1–10 species) were more difficult for the SOM to generate an accurately ranked list, with success rates varying from 100% correct down to 0% correct. However, we were able to combine the numbers of species present in a region with clustering patterns in the SOM, to further refine confidence in lists generated from these sparsely populated regions. We then used the results from the virtual world to determine confidences for lists generated from the fungal pathogen dataset. Specifically, for lists generated for Australia and its states and territories, the reliability scores were between 84–98%. We conclude that a SOM analysis is a reliable method for analysing a large dataset of potential invasive species and could be used by biosecurity agencies around the world resulting in a better overall assessment of invasion risk
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