Aerobic power and flight capacity in birds: a phylogenetic test of heart-size hypothesis

Flight capacity is one of the most important innovations in animal evolution; it only evolved in insects, birds, mammals and the extinct pterodactyls. Given that powered flight represents a demanding aerobic activity, an efficient cardiovascular system is essential for the continuous delivery of oxygen to the pectoral muscles during flight. It is well known that the limiting step in the circulation is stroke volume (the volume of blood pumped from the ventricle to the body during each beat), which is determined by the size of the ventricle. Thus, the fresh mass of the heart represents a simple and repeatable anatomical measure of the aerobic power of an animal. Although several authors have compared heart masses across bird species, a phylogenetic comparative analysis is still lacking. By compiling heart sizes for 915 species and applying several statistical procedures controlling for body size and/or testing for adaptive trends in the dataset (e.g. model selection approaches, phylogenetic generalized linear models), we found that (residuals of) heart size is consistently associated with four categories of flight capacity. In general, our results indicate that species exhibiting continuous hovering flight (i.e. hummingbirds) have substantially larger hearts than other groups, species that use flapping flight and gliding show intermediate values, and that species categorized as poor flyers show the smallest values. Our study reveals that on a broad scale, routine flight modes seem to have shaped the energetic requirements of birds sufficiently to be anatomically detected at the comparative level

Global urban environmental change drives adaptation in white clover

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale

Behavioural flexibility: evolutionary past and its role in a changing world

A través de la historia de la vida, gran parte de los organismos han desarrollado estrategias para responder a un mundo en constante cambio. Hoy en día, las actividades humanas producen cambios ambientales a una velocidad sin precedentes, lo cual se traduce en grandes desafíos para la persistencia de biodiversidad. Esta investigación evalúa las respuesta de los animales a los cambios ambientales enfocándose en la flexibilidad del comportamiento como estrategia adaptativa. En una primera aproximación a una escala evolutiva, se otorgan evidencias del vínculo hasta ahora tenue entre la cognición e historias de vida, entregando un claro apoyo a la relación entre longevidad, vida reproductiva y el tamaño del cerebro en mamíferos. La longevidad es el centro de muchas hipótesis respecto a las ventajas de desarrollar un cerebro grande, como por ejemplo en la hipótesis del buffer cognitivo y las respuestas flexibles frente a nuevos ambientes. En un segundo nivel, se abordan factores extrínsecos e intrínsecos que podrían explicar las diferencias individuales en innovación, un componente clave en la flexibilidad del comportamiento. Por medio de una aproximación experimental, se evalúan potenciales escenarios que podrían conducir a consistentes diferencias individuales en uno de los principales factores subyacentes a la innovación (i.e. la motivación), y el potencial control endocrino sobre estos escenarios. Posteriormente, con el objetivo de evaluar la respuesta de los animales frente a los cambios ambientales actuales, se explora la respuesta de los animales frente a una de las actividades humanas mas disruptivas sobre los ecosistemas, la urbanización. Por medio de un analisis filogenetico comparativo a nivel global en aves se abordan los mecanismos implicados en la perdida de biodiversidad observada en ambientes urbanos. Los resultados entregan evidencias sobre la importancia de procesos de dispersión local junto con el papel clave de los rasgos de historia de vida, pero en un sentido diferente al clasicamente pensado. Finalmente por medio de una revisión bibliográfica se entregan evidencias teóricas y empíricas que respaldan el rol clave de la flexibilidad del comportamiento en confrontar los desafíos de una vida urbana. La integración de estos resultados muestra cómo el pasado evolutivo contribuye a hacer frente a los retos ambientales actuales, y pone de relieve posibles consecuencias ante un planeta más cambiante que nuncaAcross the history of life, most of organisms have evolved proper strategies to respond to an ever-changing world. Nowadays, human-conducted environmental changes impose an unprecedented lost of biodiversity. This thesis assesses one of the key responses to actual environmental changes, behavior flexibility. In a first approximation by a phylogenetic comparative approach, strong evidences for the still tenuous link between cognition and life history is reported. The clearest support for the relationship between lifespan and brain size in mammals is showed. Lifespan is core to many hypotheses regarding the advantages of enlarged brains, like the cognitive buffer hypothesis to proper respond to novel environments. In a second level, it was explored for the drivers of innovation propensity, a key component of behavior flexibility. By mean of an experimental approach, the possible scenarios that may select for consistent individual differences in motivation, a major driver of innovation, were assessed. Consistent individual differences in motivation are reported, but heritability and endocrine control features suggest that mechanism may be different of those hypothesized. Later, to approach for the role of behavioral flexibility in changing environments, the behavior responses to one of the most disruptive effects of human activities on ecosystem, the urbanization, were assessed. First, using a global comparative analyses in birds communitiesacross the world, it was showed the importance of local processes by random dispersal effects alongside habitat filtering to explain lose of biodiversity in urbanized environments. Some phylogenetic lineages appear more likely than others to thrive in urban environments, which is related to a future-returns strategy (i.e. low brood value) that allow for decrease the cost of delay reproduction and increase the opportunities to acquiring environmental information. Second, based on a literature review, theoretical and empirical evidences are reported for argue that behavioural flexibility is an important way to deal with urban environments. The integrations of these results shows how the evolutionary past has shaped the traits that contribute to deal with actual environmental challenges, and highlight the expected consequences in a rapid changing, human-dominated world

Stay or leave? Avian behavioral responses to urbanization in Latin America

Behavioral adjustments are at the forefront of the mechanisms that birds employ to deal with environmental changes. We here review the literature focused on how behavior influences bird responses when faced with the challenges of urbanization in Latin America. Most of reviewed studies assessed for patterns of responses to urbanization with incipient information regarding the behavioral adjustments, as well as the filtering of specific behavioral phenotypes. A common and unsurprising tendency was that several avian species across Latin America are using resources from urban vegetation patches. The few experimental studies performed in urban Latin America focus on the role of personality in adjustments of foraging behavior, as well as the response to noise pollution. Nevertheless, we found no study to directly assess whether or not behavioral adjustments are related to fitness. Even so, studies assessing for the role of behavioral responses to urbanization that explicitly consider their effect on population dynamics are lacking worldwide, despite their importance for fully understanding the differential fate of species having to live in an increasingly built-up planet. Our review allowed us to identify important knowledge gaps of topics related to avian behavioral responses to urbanization, of which the following head the list: (i) behavioral adjustments in both urban greenspaces and highly developed areas; (ii) adaptiveness of avian behavioral adjustments through population dynamics; (iii) metapopulations as one of the process underlying the viability of avian bird populations; and (iv) the role of behavioral changes on evolutionary process in urban area

Worldwide bird assemblages across urban-wildland gradients

[Methods] We gathered presence/absence and abundance data from published studies and reports to characterize avian assemblages. The survey method varied across studies, but the same method was used for each habitat within a particular region, making data comparable using appropriate models.We gathered presence/absence and abundance data from published studies and reports for 319 well-characterized assemblages spanning 50 cities from Africa, Australia, Europe, North America and South America. We focused on cities with comparable survey data within urban habitats and in nearby natural habitat. The final dataset contains almost 10,000 records for 1507bird species, 66 of which are introduced (non-native) in at least one study region. Species abundance per unit area or unit time were available for 269 assemblages from 42 cities, comprising 1353 species. Following Newbold et al. (2015), we used published habitat descriptions to classify the intensity of human use in urban habitats for each assemblage: (1) highly urbanised environments mainly contain densely packed buildings with vegetation scarce or absent; (2) moderately urbanised environments are residential areas with single-family houses and associated gardens; and (3) little-urbanised environments have few buildings and abundant vegetation (e.g. urban parks). The habitats outside the city were assigned to either natural vegetation or rural habitat based on the description of the habitat given in the source paper. Standardised survey methods were used across habitats within each region.Ministerio de Ciencia e Innovación, Award: CGL2013-47448-P. ANID-FONDECYT.Peer reviewe

Urbanisation and the loss of phylogenetic diversity in birds

Despite the recognised conservation value of phylogenetic diversity, little is known about how it is affected by the urbanisation process. Combining a complete avian phylogeny with surveys along urbanisation gradients from five continents, we show that highly urbanised environments supported on average 450 million fewer years of evolutionary history than the surrounding natural environments. This loss was primarily caused by species loss and could have been higher had not been partially compensated by the addition of urban exploiters and some exotic species. Highly urbanised environments also supported fewer evolutionary distinctive species, implying a disproportionate loss of evolutionary history. Compared with highly urbanised environments, changes in phylogenetic richness and evolutionary distinctiveness were less substantial in moderately urbanised environments. Protecting pristine environments is therefore essential for maintaining phylogenetic diversity, but moderate levels of urbanisation still preserve much of the original diversity

Urbanisation and the loss of phylogenetic diversity in birds

Despite the recognised conservation value of phylogenetic diversity, little is known about how it is affected by the urbanisation process. Combining a complete avian phylogeny with surveys along urbanisation gradients from five continents, we show that highly urbanised environments supported on average 450 million fewer years of evolutionary history than the surrounding natural environments. This loss was primarily caused by species loss and could have been higher had not been partially compensated by the addition of urban exploiters and some exotic species. Highly urbanised environments also supported fewer evolutionary distinctive species, implying a disproportionate loss of evolutionary history. Compared with highly urbanised environments, changes in phylogenetic richness and evolutionary distinctiveness were less substantial in moderately urbanised environments. Protecting pristine environments is therefore essential for maintaining phylogenetic diversity, but moderate levels of urbanisation still preserve much of the original diversity.This paper is part of the project CGL2013‐47448‐P from the Spanish Government to DS and IB. CG‐L was supported by the grant PUC1203 MECESUP‐Pontifica Universidad Católica de Chile

Stay or leave? Avian behavioral responses to urbanization in Latin America

Behavioral adjustments are at the forefront of the mechanisms that birds employ to deal with environmental changes. We here review the literature focused on how behavior influences bird responses when faced with the challenges of urbanization in Latin America. Most of reviewed studies assessed for patterns of responses to urbanization with incipient information regarding the behavioral adjustments, as well as the filtering of specific behavioral phenotypes. A common and unsurprising tendency was that several avian species across Latin America are using resources from urban vegetation patches. The few experimental studies performed in urban Latin America focus on the role of personality in adjustments of foraging behavior, as well as the response to noise pollution. Nevertheless, we found no study to directly assess whether or not behavioral adjustments are related to fitness. Even so, studies assessing for the role of behavioral responses to urbanization that explicitly consider their effect on population dynamics are lacking worldwide, despite their importance for fully understanding the differential fate of species having to live in an increasingly built-up planet. Our review allowed us to identify important knowledge gaps of topics related to avian behavioral responses to urbanization, of which the following head the list: (i) behavioral adjustments in both urban greenspaces and highly developed areas; (ii) adaptiveness of avian behavioral adjustments through population dynamics; (iii) metapopulations as one of the process underlying the viability of avian bird populations; and (iv) the role of behavioral changes on evolutionary process in urban areasBehavioral adjustments are at the forefront of the mechanisms that birds employ to deal with environmental changes. We here review the literature focused on how behavior influences bird responses when faced with the challenges of urbanization in Latin America. Most of reviewed studies assessed for patterns of responses to urbanization with incipient information regarding the behavioral adjustments, as well as the filtering of specific behavioral phenotypes. A common and unsurprising tendency was that several avian species across Latin America are using resources from urban vegetation patches. The few experimental studies performed in urban Latin America focus on the role of personality in adjustments of foraging behavior, as well as the response to noise pollution. Nevertheless, we found no study to directly assess whether or not behavioral adjustments are related to fitness. Even so, studies assessing for the role of behavioral responses to urbanization that explicitly consider their effect on population dynamics are lacking worldwide, despite their importance for fully understanding the differential fate of species having to live in an increasingly built-up planet. Our review allowed us to identify important knowledge gaps of topics related to avian behavioral responses to urbanization, of which the following head the list: (i) behavioral adjustments in both urban greenspaces and highly developed areas; (ii) adaptiveness of avian behavioral adjustments through population dynamics; (iii) metapopulations as one of the process underlying the viability of avian bird populations; and (iv) the role of behavioral changes on evolutionary process in urban areasBehavioral adjustments are at the forefront of the mechanisms that birds employ to deal with environmental changes. We here review the literature focused on how behavior influences bird responses when faced with the challenges of urbanization in Latin America. Most of reviewed studies assessed for patterns of responses to urbanization with incipient information regarding the behavioral adjustments, as well as the filtering of specific behavioral phenotypes. A common and unsurprising tendency was that several avian species across Latin America are using resources from urban vegetation patches. The few experimental studies performed in urban Latin America focus on the role of personality in adjustments of foraging behavior, as well as the response to noise pollution. Nevertheless, we found no study to directly assess whether or not behavioral adjustments are related to fitness. Even so, studies assessing for the role of behavioral responses to urbanization that explicitly consider their effect on population dynamics are lacking worldwide, despite their importance for fully understanding the differential fate of species having to live in an increasingly built-up planet. Our review allowed us to identify important knowledge gaps of topics related to avian behavioral responses to urbanization, of which the following head the list: (i) behavioral adjustments in both urban greenspaces and highly developed areas; (ii) adaptiveness of avian behavioral adjustments through population dynamics; (iii) metapopulations as one of the process underlying the viability of avian bird populations; and (iv) the role of behavioral changes on evolutionary process in urban area