Showing papers by "Daniel Sol published in 2007"
TL;DR: It is proposed that temperament can and should be studied within an evolutionary ecology framework and provided a terminology that could be used as a working tool for ecological studies of temperament, which includes five major temperament trait categories: shyness‐boldness, exploration‐avoidance, activity, sociability and aggressiveness.
Abstract: Temperament describes the idea that individual behavioural differences are repeatable over time and across situations. This common phenomenon covers numerous traits, such as aggressiveness, avoidance of novelty, willingness to take risks, exploration, and sociality. The study of temperament is central to animal psychology, behavioural genetics, pharmacology, and animal husbandry, but relatively few studies have examined the ecology and evolution of temperament traits. This situation is surprising, given that temperament is likely to exert an important influence on many aspects of animal ecology and evolution, and that individual variation in temperament appears to be pervasive amongst animal species. Possible explanations for this neglect of temperament include a perceived irrelevance, an insufficient understanding of the link between temperament traits and fitness, and a lack of coherence in terminology with similar traits often given different names, or different traits given the same name. We propose that temperament can and should be studied within an evolutionary ecology framework and provide a terminology that could be used as a working tool for ecological studies of temperament. Our terminology includes five major temperament trait categories: shyness-boldness, exploration-avoidance, activity, sociability and aggressiveness. This terminology does not make inferences regarding underlying dispositions or psychological processes, which may have restrained ecologists and evolutionary biologists from working on these traits. We present extensive literature reviews that demonstrate that temperament traits are heritable, and linked to fitness and to several other traits of importance to ecology and evolution. Furthermore, we describe ecologically relevant measurement methods and point to several ecological and evolutionary topics that would benefit from considering temperament, such as phenotypic plasticity, conservation biology, population sampling, and invasion biology.
2,860 citations
TL;DR: It is shown that species with larger brains, relative to their body size, experience lower mortality than species with smaller brains, supporting the general importance of the cognitive buffer hypothesis in the evolution of large brains.
Abstract: Big brains are hypothesized to enhance survival of animals by facilitating flexible cognitive responses that buffer individuals against environmental stresses. Although this theory receives partial support from the finding that brain size limits the capacity of animals to behaviourally respond to environmental challenges, the hypothesis that large brains are associated with reduced mortality has never been empirically tested. Using extensive information on avian adult mortality from natural populations, we show here that species with larger brains, relative to their body size, experience lower mortality than species with smaller brains, supporting the general importance of the cognitive buffer hypothesis in the evolution of large brains.
195 citations
TL;DR: The results offer a novel perception of avian food stealing, which in the past was primarily seen in terms of ‘brawn’ rather than ‘brains’ and the conclusion that kleptoparasitism is associated more closely with cognition than with aggression is supported.
76 citations
TL;DR: In this paper, the role of local colonization and extinction rates in explaining the generation and maintenance of species richness gradients at the regional scale was considered, and the relative importance of direct and indirect effects of community size in explaining species richness was analyzed.
Abstract: Aim To consider the role of local colonization and extinction rates in explaining the generation and maintenance of species richness gradients at the regional scale. Location A Mediterranean biome (oak forests, deciduous forests, shrublands, pinewoods, firwoods, alpine heathlands, crops) in Catalonia, Spain. Methods We analysed the relative importance of direct and indirect effects of community size in explaining species richness gradients. Direct sampling effects of community size on species richness are predicted by Hubbell’s neutral theory of biodiversity and biogeography. The greater the number of individuals in a locality, the greater the number of species expected by random direct sampling effects. Indirect effects are predicted by the abundance‐extinction hypothesis, which states that in more productive sites increased population densities and reduced extinction rates may lead to high species richness. The study system was an altitudinal gradient of forest bird species richness. Results We found significant support for the existence of both direct and indirect effects of community size in species richness. Thus, both the neutral and the abundance‐extinction hypotheses were supported for the altitudinal species richness gradient of forest birds in Catalonia. However, these mechanisms seem to drive variation in species richness only in low-productivity areas; in high-productivity areas, species richness was uncorrelated with community size and productivity
32 citations
01 Jan 2007
TL;DR: In this article, the authors analyze how well the flexible term would have performed instead of the fixed length actually established, showing that a huge reduction of the term of concession would have dramatically decreased the firm's benefits and the user's overpayment due to the internalization of an unexpected traffic increase.
Abstract: Recent theoretical developments on concession contracts for long term infrastructure projects under uncertain demand show the benefits of allowing for flexible term contracts rather than fixing a rigid term. This study presents a simulation to compare both alternatives by using real data from the oldest Spanish toll motorway. For this purpose, we analyze how well the flexible term would have performed instead of the fixed length actually established. Our results show a huge reduction of the term of concession that would have dramatically decreased the firm?s benefits and the user?s overpayment due to the internalization of an unexpected traffic increase.
29 citations