Academic literature on the topic 'Climatic-niche evolution'

Mestrado em Ecologia Aplicada<br>A evolução do nicho climático é um dos principais fatores a moldar as dinâmicas da diversidade de muitos grupos de plantas e animais. Esta relação não revela um padrão generalizável ao longo de regiões e grupos taxonómicos. De facto, os efeitos da evolução do nicho climático na taxa de diversificação poderão ser idiossincráticos. Contudo, algumas limitações nos métodos que são usualmente usados para testar tal relação poderão condicionar o estudo destes eventos macroevolutivos. Aqui, pela primeira vez, testamos a relação entre a evolução do nicho climático e taxas de especiação num grupo taxonómico de répteis terrestres (Squamata: Lacertidae). Nós combinamos numa perspetiva bayesiana uma nova abordagem que tem em conta a heterogeneidade da taxa ao longo da história evolutiva de um grupo taxonómico e modelos não lineares. Nós mostramos que a variação da taxa de especiação de lacertídeos está relacionada com a evolução de ambas a posição do nicho e a largura do nicho relativamente à temperatura, e que esta relação é melhor explicada por um modelo quadrático. Para além disso, os nossos resultados sugerem que poderá haver um limite de variação do nicho climático para o qual a especiação não aumenta e começa a desacelerar. Especialização na largura do nicho parece atuar como o fator limitante que impede o aumento da especiação. Estes resultados poderão ser relevantes num cenário de alterações climáticas, e poderão contribuir na interpretação de tendências no futuro relativamente à diversificação de lagartos.<br>The evolution of the climatic niche is one of the main factors shaping diversity dynamics in many groups of plants and animals. This relationship does not show a pervasive pattern across regions and clades. In fact, the effects of the evolution of climatic niche on diversification rates might be idiosyncratic. However, some limitations in the methods that are commonly used to test such relationship may undermine the study of these macroevolutionary events. Here, for the first time, we examine the relationship between climatic niche evolution and rates of speciation in a clade of terrestrial reptiles (Squamata: Lacertidae). We combine in a Bayesian framework a new approach that accounts for rate heterogeneity across the evolutionary history of a clade and non-linear models. We show that the variation in the speciation rate of lacertids is related to the evolution of both niche position and niche breadth for temperature, and that a quadratic model best predicts this relationship. Moreover, our results suggest that there might be a threshold of variation in climatic niche from which speciation can no longer increase and starts to slow down. Specialization in niche breadth seems to act as the limiting factor that prevents speciation to increase. These results may be relevant under a climate change scenario, and may contribute to interpreting future trends regarding the diversification of lizards.

With close to 2100 species, the flowering plant genus Carex (Cyperaceae; sedges) is an example of an evolutionary radiation. Despite its potential for use as a model taxon in evolutionary studies, the diversification of sedges remains largely unexplored. This thesis realizes the potential of Carex as an evolutionary model group by using it to ask questions about species richness patterns. More specifically, it seeks to determine the relationship, if any, between rates of trait evolution and species richness. This tests the hypothesis that organisms with increased abilities to evolve new traits, speciate more rapidly. Morphological and ecological (habitat and climatic niche) traits are modelled on a nearly complete regional (North America north of Mexico) phylogeny and rates of trait evolution are compared among non-nested sister groups. However, before trait evolution is modelled, this work evaluates the sensitivity of climatic niche estimates to underlying distribution datasets. It tests the agreement of niche estimates derived from the commonly used online repository GBIF (the Global Biodiversity Information Facility) and county-level distributions via BONAP (the Biota of North America Program). Results showed that in the context of phylogenetic comparative analyses, it is not vital to obtain highly accurate climatic niche estimates. The second study found significant positive correlations between the rates of climatic niche, habitat and reproductive morphological evolution and species richness. This result supports the role of high trait lability in generating species richness and more generally, the idea that high trait disparity through evolutionary time leads to species success.

A major goal of ecology and evolutionary biology is to explain patterns of species richness among clades. Differences in rates of net diversification (speciation minus extinction over time) may often explain these patterns, but the factors that drive variation in diversification rates remain uncertain. Three important candidates are climatic niche position (e.g., whether clades are primarily temperate or tropical), rates of climatic niche change among species within clades, and microhabitat (e.g., aquatic, terrestrial, arboreal). The first two factors have been tested separately in several studies, but the relative importance of all three is largely unknown. Here we explore the correlates of diversification among families of frogs, which collectively represent approximate to 88% of amphibian species. We assemble and analyze data on phylogeny, climate, and microhabitat for thousands of species. We find that the best-fitting phylogenetic multiple regression model includes all three types of variables: microhabitat, rates of climatic niche change, and climatic niche position. This model explains 67% of the variation in diversification rates among frog families, with arboreal microhabitat explaining approximate to 31%, niche rates approximate to 25%, and climatic niche position approximate to 11%. Surprisingly, we show that microhabitat can have a much stronger influence on diversification than climatic niche position or rates of climatic niche change.

A major goal of evolutionary biology and ecology is to understand why species richness varies among clades. Previous studies have suggested that variation in richness among clades might be related to variation in rates of morphological evolution among clades (e.g., body size and shape). Other studies have suggested that richness patterns might be related to variation in rates of climatic-niche evolution. However, few studies, if any, have tested the relative importance of these variables in explaining patterns of richness among clades. Here, we test their relative importance among major clades of Plethodontidae, the most species-rich family of salamanders. Earlier studies have suggested that climatic-niche evolution explains patterns of diversification among plethodontid clades, whereas rates of morphological evolution do not. A subsequent study stated that rates of morphological evolution instead explained patterns of species richness among plethodontid clades (along with "ecological limits" on richness of clades, leading to saturation of clades with species, given limited resources). However, they did not consider climatic-niche evolution. Using phylogenetic multiple regression, we show that rates of climatic-niche evolution explain most variation in richness among plethodontid clades, whereas rates of morphological evolution do not. We find little evidence that ecological limits explain patterns of richness among plethodontid clades. We also test whether rates of morphological and climatic-niche evolution are correlated, and find that they are not. Overall, our results help explain richness patterns in a major amphibian group and provide possibly the first test of the relative importance of climatic niches and morphological evolution in explaining diversity patterns.

Les Angiospermes sont le clade le plus diversifié des plantes actuelles et sont exceptionnellement riches en espèces dans les régions tropicales. Dans cette thèse, j’ai étudié l’évolution des systèmes sexuels et l’histoire biogéographique de la famille des Moraceae, clade modèle utilisé pour comprendre l’origine et l’évolution de la diversité chez les Angiospermes. Dans le Chapitre I, j’ai reconstruit et calibré un nouvel arbre phylogénétique daté pour les Moraceae. J’ai ensuite utilisé cet arbre pour reconstruire les états ancestraux des systèmes sexuels chez les Moraceae et Ficus. Les âges des groupes-couronne des Moraceae et du genre Ficus sont estimés au Crétacé et à l’Eocène, respectivement. La dioécie est inférée comme l’état ancestral des systèmes sexuels chez les Moraceae, avec plusieurs transitions ultérieures vers la monoécie, y compris chez Ficus. Ce résultat suggère que la dioécie ne représente pas nécessairement un cul-de-sac évolutif. Dans le Chapitre II, j’ai reconstruit un arbre phylogénétique daté pour la tribu des Dorstenieae, distribuée principalement dans les régions tropicales, à partir d’un nouveau jeu de données génomiques nucléaires produit avec une approche Hyb-Seq. L’histoire biogéographique du groupe a ensuite été reconstruite en utilisant les modèles de dispersion-extinction-cladogenèse. Les âges des groupes-couronne des Dorstenieae et du genre Dorstenia sont estimés au Crétacé et dans la période du Crétacé au Paléocène, respectivement. Deux évènements de dispersion à longue distance depuis l’Afrique continentale vers l’Amérique du Sud ont eu lieu au Cénozoïque (Dorstenia et Brosimum s.l.). Dans le Chapitre III, j’ai testé les différences de niche climatique (température et précipitation) entre les deux systèmes sexuels (monoécie et gynodioécie) chez Ficus avec un nouveau jeu de données fiables d’occurrences spatiales et de systèmes sexuels chez 183 espèces. À cette fin, j’ai utilisé deux approches comparatives : équations d’estimation généralisées (GEE) et modèles linéaires généralisés (GLM). Une relation positive entre précipitation et gynodioécie est soutenue par les analyses GLM, et aucune méthode ne soutient une relation entre température et système sexuel. Une meilleure capacité à se disperser et le potentiel d’autopollinisation sont deux explications possibles pour la colonisation et la survie des espèces monoïques dans des environnements plus secs. Cette thèse démontre le potentiel des méthodes phylogénétiques comparatives et des données phylogénomiques pour répondre aux questions d’évolution des systèmes sexuels et de biogéographie chez les Moraceae et ouvre plusieurs nouvelles perspectives importantes méritant d’être approfondies chez d’autres clades de plantes, telles que la relation entre système sexuel et niche climatique<br>Angiosperms are the most diversified clade of extant plants and are exceptionally species-rich in tropical regions. In this thesis, I investigated breeding system evolution and biogeographic history in the family Moraceae, which I used as a model clade to understand the origin and evolution of diversity of angiosperms. In Chapter I, I reconstructed and calibrated a new dated phylogenetic tree for Moraceae as a whole. I then used this tree to reconstruct ancestral states of breeding systems in Moraceae and Ficus. The crown group ages of Moraceae and Ficus were estimated in the Cretaceous and in the Eocene, respectively. Dioecy was inferred as the ancestral breeding systems of Moraceae, with several subsequent transitions to monoecy, including in Ficus. This result suggests that dioecy is not necessarily an evolutionary dead end. In Chapter II, I reconstructed a dated phylogenetic tree for tribe Dorstenieae, mainly distributed in tropical regions, with a new data set of nuclear genomic data generated with a Hyb-Seq approach. Biogeographic history was then reconstructed using dispersal-extinction-cladogenesis models. The crown group ages of Dorstenieae and Dorstenia were estimated in the Cretaceous and in the Cretaceous/Paleocene period, respectively. Two long-distance dispersal events from continental Africa to South America occurred in the Cenozoic (Dorstenia and Brosimum s.l.). In Chapter III, I tested the climatic niche difference (temperature and precipitation) between the two breeding systems (monoecy and gynodioecy) in Ficus using a new dataset of cleaned spatial occurrence records and breeding systems for 183 species. I used two comparative approaches: generalized estimating equations (GEE) and generalized linear models (GLM). A positive relationship between precipitation and gynodioecy was supported by GLM, but not GEE analyses, and no relationship between temperature and breeding systems was supported by either method. Higher dispersal ability and the potential for self-fertilization may explain why monoecious species of Ficus have been able to colonize and survive in drier environments. This thesis highlights the potential of phylogenetic comparative methods and phylogenomic data to address questions of breeding system evolution and biogeography in Moraceae, and opens up several important new perspectives worth investigating in other plant clades, such as a relationship between breeding system and climatic niche

La niche climatique des espèces joue un rôle important dans la distribution spatiale de la biodiversité mais la manière dont les niches climatiques évoluent reste encore peu connue. Ce travail vise à révéler la manière dont les niches climatiques évoluent en général, et plus précisément à déterminer comment certaines plantes se sont adaptées aux environnements alpins. En étudiant de nombreux groupes de plantes, de poissons, de mammifères et d'oiseaux, nous avons montré que les niches climatiques évoluent le plus souvent par à-coups et non pas de manière graduelle. Les niches climatiques restent en effet stables pendant des périodes de plusieurs millions d'années puis évoluent de manière extrêmement rapide avant de se stabiliser à nouveau dans une autre gamme de climat. Des simulations ont permis de montrer que les phases de relative stabilité n'étaient pas forcément causées par une sélection stabilisante sur les niches climatiques mais pouvaient également résulter de la présence de barrières géographiques qui empêchent les espèces d'expérimenter de nouveaux climats. L'étude de l'histoire des plantes du genre Androsace a révélé que les changements rapides de niches correspondaient au contraire à l'apparition de nouveaux traits, comme la forme de vie en coussin. Ce travail montre que de nombreux facteurs influencent l'évolution des niches climatiques et souligne la nécessité de tous les étudier ensemble.

Si de nombreux animaux effectuent des migrations saisonnières, la migration des oiseaux demeure l’une des plus spectaculaires du règne animal et c’est d’abord parce qu’elle fascine les humains que cette migration est la plus étudiée depuis toujours. Mais malgré cet engouement précoce de la communauté scientifique, d’importantes interrogations persistent. Parmi celles-ci, les scénarios biogéographiques qui façonnent la distribution des espèces migratrices ou qui ont conduit des espèces ou des lignées entières à évoluer vers un comportement de migration saisonnière à longue distance restent peu compris.L'objectif de ma thèse était d’aborder ces questions à différents niveaux taxonomiques, afin d’étudier les implications écologiques et évolutives de la migration à longue distance chez les oiseaux. Plus précisément, (1) je me suis d’abord intéressé aux scénarios d’évolution biogéographique et des niches climatiques qui ont conduit à l’émergence de stratégies de migration géographique saisonnière à grande distance. (2) Resserrant le cadre taxonomique aux Charadriiformes, j’ai approfondi mes recherches sur la biogéographie de la migration en abordant la question du rôle de la migration dans les processus de diversification et la mise en place des gradients globaux de biodiversité. Pour mieux comprendre ces mécanismes évolutifs, j’ai également étudié (3) comment l’évolution de la coloration est reliée à l’évolution de stratégies de migration chez les Laridae et (4) l’influence de ces mouvements longues distances sur les autres évènements du cycle annuel chez une espèce d’oiseau marin de l’Arctique. (5) Enfin, à l’échelle intra-spécifique, je me suis penché sur la mise en place de nouvelles voies de migration chez deux de passereaux d’origine sibérienne pour explorer la question des rapides changements de distribution.Dans l'ensemble, les résultats de ces études montrent que les différentes facettes de l'écologie et l'évolution sont fortement intriquées pour comprendre l’évolution du comportement de migration longue distance. Ils montrent également l’importance de confronter plusieurs échelles taxonomiques et plusieurs facteurs, notamment temporels, pour appréhender l’histoire évolutive de ce comportement. Enfin, ils soulignent la difficulté de prévoir les changements de distribution des oiseaux migrateurs dans un contexte de changements globaux<br>Many animals make seasonal migrations, but bird migration remains one of the most spectacular in the animal kingdom and it is mainly because it fascinates humans that this migration has been the most studied historically. However, despite this early interest of the scientific community, important issues have remained unresolved. Among these, the biogeographical scenarios that shape the distribution of migratory species or that have led species or entire lineages to evolve towards long-distance migration behaviour are still poorly understood.The aim of my thesis was to address these questions at different taxonomic levels, in order to study the ecological and evolutionary implications of long-distance migration in birds. More precisely, (1) I first focused on biogeographic theories of migration evolution at a global scale, coupled with the study of the tracking of ecological niches during the annual cycle. (2) Narrowing the taxonomic framework to the Charadriiformes, I pursued my research on the biogeography of migration by also addressing the question of the role of migration in diversification processes and in the establishment of latitudinal diversity gradients. To better understand these mechanisms, I also studied (3) the selective pressures encountered during the annual cycle of a migratory bird family and (4) the influence of these long-distance movements on other events of the annual cycle in an Arctic seabird species. (5) Finally, at the intraspecific level, I investigated the establishment of new migration routes in two passerines of Siberian origin to explore the issue of rapid changes in distribution.Taken together, the results of these studies highlight how tightly the different facets of invasion ecology and evolution are interrelated in understanding the evolution of long-distance migration behaviour. They also highlight the importance of comparing several taxonomic levels and several factors, particularly temporal factors, to assess the evolutionary history of this complex behaviour. Finally, they stress the difficulty of predicting changes in the distribution of migratory birds in a context of global changes