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Colonization of a new environment may trigger an evolutionary radiation, defined as an accelerated accumulation of species in a short period of time. However, how often colonization events trigger such radiations is still an open question. We studied the worldwide dispersal of Caninae to investigate whether the invasion of new continents resulted in elevated species diversification. We used a combination of ancestral range estimation and phylogenetic analyses to estimate the ancestral ranges of 56 extant and extinct species of Caninae, as well as variation in speciation and extinction rates through time and across clades. Our findings indicate that canids experienced an evolutionary radiation event when lineages were able to reach Eurasia and South America around 11 million years ago. A large number of species arising in a short period of time suggests that canids experienced ecological opportunity events within the new areas, implying that the differences in the ecological settings between continents, and size variation among Canidae and other carnivores may be responsible for the variation in clade dynamics. We suggest that the increase of grasslands and the new herbivorous fauna that came with it were the major forces responsible for the diversification of wolves in North America, while empty niches and the absence of competitors can explain the success of canids in Africa and South America. Interaction with other carnivores probably also affected the diversification dynamics of canids.

Native plant communities are commonly invaded by invasive plants to different degrees. However, the relative contribution of the invasive plant abundance vs. phylogenetic evenness to the responses of wetland communities to different degrees of invasion is still unclear. In addition, whether such contribution varies with environmental conditions such as flooding is also unclear. To address these questions, we chose Alternanthera philoxeroides as the invasive plant, and set up four invasive degrees by changing the community species composition under both flooding and non-flooding conditions. The relative abundance of A. philoxeroides and phylogenetic evenness changed simultaneously with the change in the community invasion degree. The invasion degree significantly affected the individual biomass of A. philoxeroides and some native species. Variation partitioning showed that the relative abundance of A. philoxeroides contributed more to variation in community indicators than phylogenetic evenness, regardless of flooding. Spearman rank correlation test showed that the relative abundance of A. philoxeroides was negatively correlated with the individual biomass of A. philoxeroides and some native species, while the phylogenetic evenness was positively correlated with only a few native species. And their correlation strength and significance were all affected by specific species and flooded environment. In conclusion, our results suggest that the relative abundance of A. philoxeroides can more effectively explain the wetland community response to different invasion degrees than phylogenetic evenness, regardless of flooding.

The impact of climate change on global biodiversity is firmly established, but the differential effect of climate change on populations within the same species is rarely considered. In ectotherms, melanism (i.e. darker integument due to heavier deposition of melanin) can significantly influence thermoregulation, as dark individuals generally heat more and faster than bright ones. Therefore, darker ectotherms might be more susceptible to climate change. Using the colour-polyphenic lizard Karusasaurus polyzonus (Squamata: Cordylidae), we hypothesized that, under future climatic projections, darker populations will decrease their activity time more than brighter ones due to their greater potential for overheating. To test this, we mechanistically modelled the body temperatures of 56 individuals from five differently coloured populations under present and future climate conditions. We first measured morphological traits and integumentary reflectance from live animals, and then collected physiological data from the literature. We used a biophysical model to compute activity time of individual lizards as proxy for their viability, and thereby predict how different populations will cope with future climate conditions. Contrary to our expectations, we found that all populations will increase activity time and, specifically, that darker populations will become relatively more active than bright ones. This suggests that darker populations of K. polyzonus may benefit from global warming. Our study emphasizes the importance of accounting for variation between populations when studying responses to climate change, as we must consider these variations to develop efficient and specific conservation strategies. A free Plain Language Summary can be found within the Supporting Information of this article.

Background and Aims The Canary Islands have strong floristic affinities with the Mediterranean Basin. One of the most characteristic and diverse vegetation belts of the archipelago is the thermophilous woodland (between 200 and 900 m.a.s.l.). This thermophilous plant community consists of many non-endemic species shared with the Mediterranean Floristic Region together with Canarian endemic species. Consequently, phytogeographic studies have historically proposed the hypothesis of an origin of the Canarian thermophilous species following the establishment of the summer-dry mediterranean climate in the Mediterranean Basin around 2.8 million years ago. Methods Time-calibrated phylogenies for 39 plant groups including Canarian thermophilous species were primarily analysed to infer colonization times. In particular, we used 26 previously published phylogenies together with 13 new time-calibrated phylogenies (including newly generated plastid and nuclear DNA sequence data) to assess whether the time interval between stem and crown ages of Canarian thermophilous lineages postdates 2.8 Ma. For lineages postdating this time threshold, we additionally conducted ancestral area reconstructions to infer the potential source area for colonization. Key Results A total of 43 Canarian thermophilous lineages were identified from 39 plant groups. Both mediterranean (16) and pre-mediterranean (9) plant lineages were found. However, we failed to determine the temporal origin for 18 lineages because a stem–crown time interval overlaps with the 2.8-Ma threshold. The spatial origin of thermophilous lineages was also heterogeneous, including ancestral areas from the Mediterranean Basin (nine) and other regions (six). Conclusions Our findings reveal an unexpectedly heterogeneous origin of the Canarian thermophilous species in terms of colonization times and mainland source areas. A substantial proportion of the lineages arrived in the Canaries before the summer-dry climate was established in the Mediterranean Basin. The complex temporal and geographic origin of Canarian thermophilous species challenges the view of the Canary Islands (and Madeira) as a subregion within the Mediterranean Floristic Region.

Adaptive radiation is proposed to play a key role in generating differences in species richness among lineages and geographical regions. Due to the importance of ecological divergence in adaptive radiation, species richness is predicted to be influenced by equilibrium diversity dynamics, although the concept continues to generate much debate. An additional important question is whether radiating clades have intrinsic biological characteristics that make them particularly prone to diversify. We tackle these questions by analysing (i) the temporal patterns of diversification of Caribbean Eleutherodactylus frogs, and (ii) assembly of the complete native anuran community of the Caribbean archipelago (197 species), testing for the presence of equilibrium dynamics and whether diversification patterns of Eleutherodactylus differ from those of the rest of the Caribbean anurans. Diversification rates follow the predicted pattern of rapid diversification early in the radiation which gradually decreases towards the present. Eleutherodactylus diversification is significantly faster than that of the Caribbean anuran community, and although equilibrium dynamics influence richness of all Caribbean anurans, Eleutherodactylus shows higher carrying capacity. Our results indicate that ecological opportunity per se is not sufficient for adaptive radiation and that diverse lineages present intrinsic characteristics that enable them to make the most of available opportunity.

Elevated CO2 concentrations (eCO2) have been widely observed to stimulate microbial growth. However, the effect of eCO2 on soil microbial biomass may depend on several factors and their interactions, such as the increase in atmospheric CO2 levels, experimental duration and mean annual precipitation (MAP). We conducted a global meta-analysis from 62 studies that included the responses of soil microbial biomass to eCO2. We found a significant positive eCO2 effect on the bacterial biomass (+9.1 %), fungi (+11 %), arbuscular mycorrhizal fungi (AMF) (+10.2 %) and actinomycetes (ACT) (+16.4 %). The positive effects were mainly observed in studies with low eCO2 levels (≤200 ppm) rather than high levels of eCO2 (>200 ppm), which could be attributable to soil N limitation. It was also found that eCO2 had a significant positive effect on soil microbial biomass in the short term (≤3 y) and under a high MAP (>800 mm). Importantly, we revealed interactive effects between the eCO2 levels, experimental duration on soil microbial biomass. With an increase in eCO2, the total microbial biomass (TMB), bacterial biomass and fungal biomass decreased over the long term (>3 y). These findings indicate the need to incorporate interactions between eCO2 and environmental factors into ecosystem models, to predict future global climate change effects more accurately and their impact on ecosystem functions.

AimBiodiversity on islands is influenced by geophysical processes and sea-level fluctuations. Oceanic islands (never connected to a landmass) are initially vacant with diversity accumulating via colonisation and speciation, and then declining as islands shrink. Continental islands have species upon disconnection from the mainland and may have transient land-bridge connections. Theoretical predictions for the effects of these geophysical processes on rates of colonisation, speciation, and extinction have been proposed. However, paleogeographic reconstructions are currently unavailable for most islands, and phylogenetic models overlook island ontogeny, sea-level changes, or past landmass connections. We analyse to what extent ignoring geodynamics in the inference model affects model predictions when confronted with data simulated with geodynamics.LocationSimulations of oceanic and continental islands.TaxaSimulated lineages.MethodsWe extend the island biogeography simulation model DAISIE to include: (i) area-dependent rates of colonisation and diversification associated with island ontogeny and sea-level fluctuations, (ii) continental islands with biota present upon separation from the mainland, and (iii) shifts in colonisation to mimic temporary land-bridges. We quantify the error of ignoring geodynamic processes by applying DAISIE's inference method to geodynamic simulations.ResultsRobustness of the model to dynamic island area is generally high for oceanic islands and for continental islands that have been separated for a long time, suggesting that it is possible to obtain reliable results when ignoring geodynamics. However, for continental islands that have been recently or frequently connected, robustness of the model is low.Main conclusionsUnder many island biogeographic geodynamic scenarios (oceanic islands and ancient continental fragments) a simple phylogenetic model ignoring geodynamics is empirically applicable and informative. However, recent connection to the continent cannot be ignored, requiring new model development. Our results show that for oceanic islands, reliable insights can be obtained from phylogenetic data in the absence of paleogeographic reconstructions of island area.

Anthus correndera has a wide distribution in southern South America with several subspecies assigned to the taxon. We take an integrative approach, analysing genome-wide single-nucleotide polymorphism (SNP) data collected using ddRAD sequencing, songs and linear morphological data, to evaluate the evolutionary history of A. correndera and divergence of each subspecies. The final genomic data set of 11,467 SNPs for 40 individuals supports a primary divergence of two main lineages: one in the Andean highlands and another in the lowlands. Estimated divergence times suggest the Andean and lowland groups diverged around 135.5 to 99 thousand years ago (Ka), whereas divergence among populations within each group was much more recent, ranging from 54.7 Ka among the Andean populations to as recent as 20.6 Ka among the lowland populations. Analyses of territorial songs showed slight differences between all operational taxonomic units; however, morphological differences were apparent only between geographically distant populations (i.e. Puna vs. South Georgia). Based on multiple lines of evidence, we propose to reduce the number of subspecies within the correndera complex to three: A. c. calcaratus on the Andean Altiplano (treating A. c. catamarcae as a junior synonym), A. c. correndera in the lowlands (treating A. c. chilensis and A. c. grayi as junior synonyms), and A. c. antarcticus on South Georgia.

Sociability – an individual’s propensity to engage in group activities – is a conserved trait throughout most of life. Sociability can be considered as a personality type in humans when showing correlated sociability measures across different assays. Our knowledge of the mechanisms that drive sociability and explain its inter-individual variation is still limited. To enhance our mechanistic understanding, the genetically tractable Drosophila melanogaster is increasingly being used as a model for research on social behaviour. High and low sociability phenotypes, indicative of a variation of sociability levels among the population have been documented in this species. However, sociability traits have been measured through unidimensional assays, which do not allow us to assess whether sociability is a personality type in fruit flies. Here, we present a multidimensional approach to assess sociability, using a combination of three behavioural assays that each captures a different functional feature of social interactions in D.melanogaster. We applied our approach to the Drosophila melanogaster Genetic Reference Panel (DGRP) lines and revealed continuous variation in the strength of response to others. We found that sociability levels varied between genetically distinct lines, indicative of a genetic component of sociability.The three sociability traits were, however, not correlated, making it questionable whether sociability can be considered a personality type in D. melanogaster.

Aim Neotropical savanna birds occur north and south of, but mostly not in the Amazon Basin, except for a few isolated savanna patches. Here, we investigate the phylogeography of 23 taxa of Neotropical savanna birds co-distributed across multiple isolated savanna patches to assess to what extent these species have a shared history of spatial diversification. We explore the role of the forested Amazon Basin as a vicariant barrier separating northern and southern populations, particularly focusing on the role of the coastal savannas of Amapa as a potential corridor of gene flow between northern and southern populations. Location Neotropical savannas. Taxon Aves. Method We employ 775 mtDNA samples of 24 co-distributed savanna bird taxa from all major savanna patches in South America to infer phylogeographic patterns. For this purpose, we use 24 genomic samples (UCEs) of a subset of 12 taxa in addition to the mtDNA samples to estimate timing of divergence across the Amazon Basin. We use phylogeographic concordance factors (PCF) to assess the level of phylogeographic congruence across co-distributed taxa. Finally, we assess to which level physical distance drives genetic structuring by estimating isolation-by-distance (IBD) effects. Results We find that although the study taxa generally do not share similar diversification patterns geographically, many have at least two distinct genetic groups, one north and one south of the Amazon Basin, that have only recently diverged. The timing of divergence between both areas is generally centered in the late Pleistocene, but somewhat variable, indicating there is no single vicariant event responsible for driving diversification. Main conclusions Variability in divergence times indicates that landscape processes have not led to shared phylogeographic responses, which indicates a relatively minor role for vicariance. Shallow divergences suggest that Neotropical grassland habitats may have recently been more connected or that gene flow has played an important role. We did not find evidence of a single dominant corridor of dispersal between savannas north and south of the forested Amazon Basin.

One of the primary goals of macroevolutionary biology has been to explain general trends in long‐term diversity patterns, including whether such patterns correspond to an upscaling of processes occurring at lower scales. Reconstructed phylogenies often show decelerated lineage accumulation over time. This pattern has often been interpreted as the result of diversity‐dependent (DD) diversification, where the accumulation of species causes diversification to decrease through niche filling. However, other processes can also produce such a slowdown, including time dependence without diversity dependence. To test whether phylogenetic branching patterns can be used to distinguish these two mechanisms, we formulated a time‐dependent, but diversity‐independent model that matches the expected diversity through time of a DD model. We simulated phylogenies under each model and studied how well likelihood methods could recover the true diversification mode. Standard model selection criteria always recovered diversity dependence, even when it was not present. We correct for this bias by using a bootstrap method and find that neither model is decisively supported. This implies that the branching pattern of reconstructed trees contains insufficient information to detect the presence or absence of diversity dependence. We advocate that tests encompassing additional data, for example, traits or range distributions, are needed to evaluate how diversity drives macroevolutionary trends.

Phenotypic plasticity allows individuals to cope with different environmental conditions without the need for genetic adaptation. Consequently, plasticity affects the nature and strength of selection on traits. Plasticity enables individuals to experience novel selection pressures, for example through migration, possibly leading to genetic adaptation. At the same time, plasticity may shield the genotype from selection, impeding genetic adaptation. Plasticity, therefore, can have opposing effects on evolutionary change and population divergence.The visual system of cichlid fish is a suitable model trait to study the relationship between plasticity and evolutionary change, because of the high species richness and the variation among species in visual habitat. Furthermore, plasticity in the expression of genes involved in the cichlid’ visual system is well established. Here, we test whether visual plasticity is correlated to the degree of ecological specialisation and clade species richness. We quantify plasticity in the expression of these genes in species from species-poor and species-rich clades, inhabiting different visual habitats in nature, by exposing individuals to different light conditions and determining light-induced variation in gene expression. Preliminary results indicate that expression indeed differs among light treatments, in multiple species. We expect our study to provide a better understanding of the impact of phenotypic plasticity on divergent evolution.

Compared to other regions, the drivers of diversification in Africa are poorly understood. We studied a radiation of insects with over 100 species occurring in a wide range of habitats across the Afrotropics to investigate the fundamental evolutionary processes and geological events that generate and maintain patterns of species richness on the continent. By investigating the evolutionary history of Bicyclus butterflies within a phylogenetic framework, we inferred the group’s origin at the Oligo-Miocene boundary from ancestors in the Congolian rainforests of central Africa. Abrupt climatic fluctuations during the Miocene (ca. 19–17 Ma) likely fragmented ancestral populations, resulting in at least eight early-divergent lineages. Only one of these lineages appears to have diversified during the drastic climate and biome changes of the early Miocene, radiating into the largest group of extant species. The other seven lineages diversified in forest ecosystems during the late Miocene and Pleistocene when climatic conditions were more favorable—warmer and wetter. Our results suggest changing Neogene climate, uplift of eastern African orogens, and biotic interactions have had different effects on the various subclades of Bicyclus, producing one of the most spectacular butterfly radiations in Africa. [Afrotropics; biodiversity; biome; biotic interactions; Court Jester; extinction; grasslands; paleoclimates; Red Queen; refugia forests; dependent-diversification; speciation.]

Aim Rates of colonization, speciation and extinction determine species richness and endemism in insular systems. The general dynamic model of island biogeography (GDM) predicts that speciation and extinction rates depend on island area and elevation via their control on ecological limits to diversification and therefore covary with an island's geological history. Additionally, the colonization rate may increase with area and elevation through the 'target effect', which can be mediated by reduced 'environmental filtering'. Here we test whether the area and depth expansion of an island-like ecosystem, a lake, caused a shift in diversity dynamics. Location Lake Biwa, Japan, whose geological history and biota are well documented. Taxon Fishes. Methods We extended the phylogenetic island biogeography framework DAISIE (Dynamic Assembly of Island biota through Speciation, Immigration and Extinction) to accommodate time-shifts in macroevolutionary rates and in carrying capacity. Using phylogenetic information on colonization and speciation times for the complete Lake Biwa fish community (70 taxa), we tested for a shift in macroevolutionary assembly rates and reconstructed the temporal diversity trajectory in the lake. We assessed the power to identify a shift through a wide range of scenarios and benchmarked against simulated fossil records. Results We detected an increase in colonization rate of fishes at 0.2 million years ago (Ma), with limited support for the existence of ecological limits. The reconstructed diversity trajectory was close to a source-sink equilibrium diversity prior to the shift and remained well below a new shift-driven elevated equilibrium thereafter. We found sufficient power to identify an increase in colonization rate up to 1.5 Ma, whereas extinction concealed the signal of earlier shifts. Main conclusions The fish diversity dynamics of Lake Biwa show a response to changes in area and depth and phylogenies carry a signature of these changes. The detected increase in colonization rate following Lake Biwa's expansion, elevating the fish diversity, is unlikely due to a predicted increase in ecological limits feeding back on colonization rate. We therefore call for (additional) explanations: the target effect, whereby larger islands attract more species, and reduced environmental filtering due to higher habitat diversity associated with increased lake area/depth.

To successfully colonize new habitats, organisms not only need to gain access to it, but also need to cope with the selective pressures imposed by the local biotic and abiotic conditions. The number of immigrants, the preadaptation to the local habitat and the presence of competitors are important factors determining the success of colonization. Here, using an experimental set-up, we test the combined effect of propagule pressure, preadaptation and interspecific competition on the colonization success of new habitats using the two-spotted spider mite (Tetranychus urticae) as our model system and the red spider mite (Tetranychus evansi) as a competitor. Our results show that propagule pressure and preadaptation positively affect colonization success. More successful populations reach larger final population sizes either by having higher per capita growth rate (due to preadaptation effect) or by starting a population with a larger number of individuals. Although populations are more successful colonizing non-competitive environments than competitive ones, propagule pressure and preadaptation counteract the negative effects of competition, promoting colonization success. Our results show the importance of propagule pressure and preadaptation to cope both with the exigencies of the new environment and the community context for successful colonization of new habitats.

Euphilotes ancilla purpura and cryptica (Lycaenidae), butterflies endemic to the Spring Mountains (Clark Co., Nevada), have been described as two univoltine, temporally isolated, sympatric taxa that utilize different early- and late-flowering larval host plant varieties (Eriogonum umbellatum). However, our results from field and laboratory indicate that this is not the case. The subspecies overlap in timing of adult reproductive flight (compilation of field records 1977 to 2018) and laboratory emergence of adults from early-season, non-diapause pupae indicate butterflies are not univoltine. Genetic samples collected from putative E. a. purpura (Early cohort) and cryptica (Late cohort) subpopulations show no evidence of genetic structure indicative of allochronic isolation in phylogenies of 26 mitochondrial DNA COI haplotypes and 18 nuclear ITS1 alleles. Analysis of molecular variance revealed 89% of mitochondrial DNA variation structured within and among subpopulations, with only 11% between the purportedly isolated subspecies. Analysis of isolation and migration indicated gene flow from the Early to Late cohort was 3 × greater than in the opposite direction. We conclude that, rather than two separate subspecies, Euphilotes ancilla exists in a network of partially interconnected subpopulations extending from 1750 to 3000 m across much of the Spring Mountains. Gene flow is related to the timing of adult flight and host plant flowering, contributing to the genetic variation in phenology necessary for evolutionary tracking of shifting flowering periods of larval host plants. Maintenance of connectivity and gene flow across the Spring Mountains is therefore essential for population persistence of both cohorts in the face of environmental change.

International audience; Phylogenetic trees are types of networks that describe the temporal relationship between individuals, species, or other units that are subject to evolutionary diversification. Many phylogenetic trees are constructed from molecular data that is often only available for extant species, and hence they lack all or some of the branches that did not make it into the present. This feature makes inference on the diversification process challenging. For relatively simple diversification models, analytical or numerical methods to compute the likelihood exist, but these do not work for more realistic models in which the likelihood depends on properties of the missing lineages. In this article, we study a general class of species diversification models, and we provide an expectation-maximization framework in combination with a uniform sampling scheme to perform maximum likelihood estimation of the parameters of the diversification process.

In plant communities, genotypic diversity can impact the plant community structure and ecosystem functions, but related research has focused on native plants. Therefore, whether genotypic diversity affects the growth of invasive plants and then changes the wetland microecosystem remains unresolved. In this study, six different genotypes of Hydrocotyle vulgaris, a common invasive plant in China, were selected to construct populations with three different genotypic diversity levels (one, three, and six genotype combinations, respectively) to explore the effects of different genotypic diversity levels on the growth and physiological traits of H. vulgaris, and soil nutrients and greenhouse gas emissions of the wetland microecosystem under flooding conditions. We found that genotypic diversity improved the leaf area, root to shoot ratio and photosynthetic physiological traits of H. vulgaris, especially under flooding. Moreover, genotypic diversity increased soil organic matter (SOM) contents in the wetland microecosystem, while it reduced the cumulative nitrous oxide emissions under flooding conditions. Overall, genotype diversity improved photosynthetic traits of H. vulgaris, further increased SOM, and reduced the N2O emissions of the wetland microecosystem. The results of this study can provide a theoretical basis for exploring how genotypic diversity levels affect the invasiveness of invasive plants and ecosystems in wetland microecosystems.

Understanding the mechanisms that generate the outstanding biological diversity on our planet has been extensively studied. However, to this date many questions remain unresolved. A fundamental process that produces biodiversity is divergent adaptation: here populations diversify by adapting to different environmental conditions. In this project, I investigated the role of the sensory system in this process, as sensory perception is critical for survival and reproduction: How do sensory systems adapt to local environments and (how) does individual flexibility contribute to this process? The fish visual system provides an excellent opportunity to study these questions as it shows extensive variation among species/populations. Fish inhabit different visual environments, as a result of wavelength-dependent light attenuation in water. There are strong indications that adaptation of the visual pigments in fish eyes plays a role in the origin and persistence of species. In this thesis I focused on cichlid fish, one of the most species-rich vertebrate families. At the level of visual pigment molecular composition, I showed that closely related species deal in different ways with variation in light conditions and differ in their plastic response to experimental light treatments. Despite these differences, fish did not go where they saw best in a behavioural choice experiment. Instead, they had a general preference for blue light. Finally, in a comparative analysis I found no evidence that diversification rates depend on the visual environment of a lineage. Together, my findings highlight that vision rapidly diverges between species/populations, impacts behaviour and is also influenced by individual flexibility.

Few biological groups have a well-documented fossil history, detailed trait datasets, reliable distribution maps, and are distributed on a global scale. The Canidae family is one of them, which allows us to tackle several topics related to evolutionary processes and species’ relationship with their environment. Here, I bring a broader view on distinct spatial patterns of Canidae, elucidating many points that are not yet very well understood about this group. By assembling distinct datasets (e.g., phylogenetic trees, paleontological data, species distribution maps, and environmental variables) together with several methods to extract information from these data, I demonstrate which were the main continental dispersal events over the last 13 million years in Canidae, and how these events shaped the diversification patterns of this clade leading to explosive diversification right after the colonization of new areas. I also show that environmental factors are more important than species interactions to explain how Canidae assemblages are structured spatially at the present. Moreover, I demonstrate the drastic climatic scenario for the majority of canids around the world during the next 54 years. In this thesis, I also test if diversification rates of canids are associated with distinct areas around the planet. The results show that when fossils species are incorporated in the analyses distinct diversification patterns are not related to geographic areas.

Group-living facilitates cooperation between individuals, but also creates competition for limited resources. Individuals should thus modulate their reproductive output in response to the presence of others. However, mechanisms that lead to such social context-dependent modulation of reproduction are poorly understood. In the fruit fly Drosophila melanogaster, females actively attract conspecifics to lay eggs on the same resources, generating groups in which individuals may cooperate or compete. The genetic tractability of this species gave me an opportunity to dissect the mechanisms by which females adjust their behaviour and physiology to their social environment. I discovered social facilitation of oogenesis and egg-laying in Drosophila melanogaster and described the neuro-hormonal mechanisms underlying this modulation. I demonstrated that social environment affects ovarian activity of females in a density-dependent manner. I showed that these responses to the presence of others are mediated by vision through the motion detection pathway and are the result of the stimulation of the juvenile hormone pathway. While social modulation of reproduction is considered a sign of sociality and is mostly expressed in social hymenopterans, my findings thus demonstrate that such phenomenon can already be found in rather solitary species such as D. melanogaster, making the concept of solitary vs social species a bit artificial. I moreover proposed a new approach to explore the variation in sociability among D. melanogaster through the quantification of multiple sociability traits. I found significant variation between the flies in the strength of responses to others, demonstrating the existence of a sociability spectrum in this species.

Herbivore diets are often generalistic, and communities of herbivores tend to share much of their diets. In the tropical lowlands of Malaysian Borneo, tens of different noncarnivorous land snail species are able to coexist in communities on limestone outcrops. We tried to answer the question whether diet differentiation plays a role in their coexistence. We show, with a large metabarcoding study of the plant diet from gut contents of 658 individual snails (from 26 species, with a focus on three of the most common species in the region), that the different snail species indeed share much of their plant diet, but that mean diet richness varies strongly among species (up to 15.3×). These differences are mostly explained by snail size, with larger snails having wider diets. Furthermore, phylogenetic analyses of the plant diet by individual snails showed signs of clustering in c. 28% of the individuals, possibly suggesting phylogenetic specialization, although such clustering was weak when diets were considered by species. We discuss how observed trends in diet richness and diet clustering could also be explained by random feeding, with larger species simply eating more or less specifically, and by other, noncompetitive interactions, such as snails avoiding desiccation. Our study shows how to efficiently put the power of metabarcoding to work in unravelling the complex community processes commonly encountered in tropical ecosystems and is thus of substantial relevance to both community ecologists and conservationists.

Low-elevation regions harbour the majority of the world's species diversity compared to high-elevation areas. This global gradient suggests that lowland species have had more time to diversify, or that net diversification rates have been higher in the lowlands. However, highlands seem to be cradles of diversity as they contain many young endemics, suggesting that their rates of speciation are exceptionally fast. Here we use a phylogenetic diversification model that accounts for the dispersal of species between different elevations to examine the evolutionary dynamics of the elevational diversity gradient in passerine birds, a group that has radiated globally to occupy almost all elevations and latitudes. We find strong support for a model in which passerines diversify at the same rate in the highlands and the lowlands but in which the per-capita rate of dispersal from high to low elevations is more than twice as fast as that in the reverse direction. This suggests that while there is no consistent trend in diversification across elevations, part of the diversity generated by highland regions migrates into the lowlands, thus setting up the observed gradient in passerine diversity. We find that this process drives tropical regions but for temperate areas, the analysis could be hampered by their lower richness. Despite their lower diversity, highland regions are disproportionally important for maintaining diversity in the adjacent lowlands.

Incomplete or geographically biased sampling poses significant problems for research in phylogeography, population genetics, phylogenetics, and species delimitation. Despite the power of using genome-wide genetic markers in systematics and related fields, approaches such as the multispecies coalescent remain unable to easily account for unsampled lineages. The Empidonax difficilis / E. occidentalis complex of small tyrannid flycatchers (Aves: Tyrannidae) is a classic example of a widely distributed species with limited phenotypic geographic variation that was broken into two largely cryptic (or sibling) lineages following extensive study. Though the group is well-characterized north of the U.S. Mexico border, the evolutionary distinctiveness and phylogenetic relationships of southern populations remain obscure. In this paper, we use dense genomic and geographic sampling across the majority of the range of the E. difficilis / E . occidentalis complex to assess whether current taxonomy and species limits reflect underlying evolutionary patterns, or whether they are an artifact of historically biased or incomplete sampling. We find that additional samples from Mexico render the widely recognized species-level lineage E. occidentalis paraphyletic, though it retains support in the best-fit species delimitation model from clustering analyses. We further identify a highly divergent unrecognized lineage in a previously unsampled portion of the group's range, which a cline analysis suggests is more reproductively isolated than the currently recognized species E. difficilis and E. occidentalis. Our phylogeny supports a southern origin of these taxa. Our results highlight the pervasive impacts of biased geographic sampling, even in well-studied vertebrate groups like birds, and illustrate what is a common problem when attempting to define species in the face of recent divergence and reticulate evolution.

The evolution of Neotropical birds of open landscapes remains largely unstudied. We investigate the diversification and biogeography of a group of Neotropical obligate grassland birds (Anthus: Motacillidae). We use a multilocus phylogeny of 22 taxa of Anthus to test the hypothesis that these birds radiated contemporaneously with the development of grasslands in South America. We employ the R package DDD to analyze the dynamics of Anthus diversification across time in Neotropical grasslands, explicitly testing for shifts in dynamics associated with the Miocene development of grasslands, the putative Pleistocene expansion of arid lowland biomes, and Pleistocene sundering of Andean highland grasslands. A lineage-through-time plot revealed increases in the number of lineages, and DDD detected shifts to a higher clade-level carrying capacity during the late Miocene, indicating an early burst of diversification associated with grassland colonization. However, we could not corroborate the shift using power analysis, probably reflecting the small number of tips in our tree. We found evidence of a divergence at similar to 1 Mya between northern and southern Amazonian populations of Anthus lutescens, countering Haffer's idea of Pleistocene expansion of open biomes in the Amazon Basin. We used BioGeoBears to investigate ancestral areas and directionality of colonization of Neotropical grasslands. Members of the genus diversified into, out of, and within the Andes, within-Andean diversification being mostly Pleistocene in origin.

Body mass has been considered one of the most critical organismal traits, and its role in many ecological processes has been widely studied. In hummingbirds, body mass has been linked to ecological features such as foraging performance, metabolic rates, and cost of flying, among others. We used an evolutionary approach to test whether body mass is a good predictor of two of the main ecological features of hummingbirds: their abundances and behavioral dominance. To determine whether a species was abundant and/or behaviorally dominant, we used information from the literature on 249 hummingbird species. For abundance, we classified a species as “plentiful” if it was described as the most abundant species in at least part of its geographic distribution, while we deemed a species to be “behaviorally dominant” when it was described as pugnacious (notably aggressive). We found that plentiful hummingbird species had intermediate body masses and were more phylogenetically related to each other than expected by chance. Conversely, behaviorally dominant species tended to have larger body masses and showed a random pattern of distribution in the phylogeny. Additionally, small‐bodied hummingbird species were not considered plentiful by our definition and did not exhibit behavioral dominance. These results suggest a link between body mass, abundance, and behavioral dominance in hummingbirds. Our findings indicate the existence of a body mass range associated with the capacity of hummingbird species to be plentiful, behaviorally dominant, or to show both traits. The mechanisms behind these relationships are still unclear; however, our results provide support for the hypothesis that body mass is a supertrait that explains abundance and behavioral dominance in hummingbirds.

Aim Island biogeography theory describes how island size and isolation determine population colonization success. Large islands sustain larger populations than small ones and experience less demographic stochasticity, thus a lower extinction risk. Nearby islands are more likely to be colonized than distant ones, because they receive more immigrants from the mainland. However, local conditions on islands are often different from those on the mainland; therefore, populations on recently colonized islands also need to adapt. Island size and isolation are known to impact the build-up of genetic variation necessary for adaptation; hence, we integrated island biogeography with evolution experimentally to gain a better understanding of the roles of island size and isolation in biodiversity patterns. Location Laboratory, Ghent University, Belgium. Time period October 2013 to June 2014. Major taxa studied Two-spotted spider mite (Tetranychus urticae). Methods Using experimental evolution, we studied the effects of island size and isolation on colonization, extinction and adaptation of the two-spotted spider mite to new islands. The mainland population consisted of bean plants and the islands of tomato plants (a known challenging condition). Islands differed in their size (number of plants) and in the number of immigrants (females, the dispersive stage) they received from the mainland. Results Island size and dispersal decreased extinction risk and increased colonization success and adaptation. Populations on small islands, which are most affected by extinction, were rescued demographically by an increase in dispersal. However, they were never able to adapt. Main conclusions Evolutionary rescue via dispersal is possible only when populations are sufficiently large; small populations cannot adapt, because they lack the genetic variation necessary for local adaptation. Hence, in addition to the effects of island size and dispersal on the ecological processes of colonization and extinction, our results show that island size and dispersal can jointly affect the evolutionary process of adaptation to novel habitats.

Neotropical grassland birds are intimately tied to their habitat and form a phylogenetically diverse group that has been poorly studied from an evolutionary point of view. Here we present a brief review of the biogeographical history of Neotropical grasslands of relevance to grassland birds. Based on this review, we have formulated the most relevant hypotheses related to the diversification and evolution of Neotropical grassland birds. Several of the hypotheses tested are complementary to those that can be tested for forest birds and may offer the researcher fruitful foci of study for assessing the role of South American geological evolution in shaping the diversification of the world’s most diverse avifauna.

The thermal environment can affect the evolution of morpho-behavioral adaptations of ectotherms. Heat is transferred from substrates to organisms by conduction and reflected radiation. Because brightness influences the degree of heat absorption, substrates could affect the evolution of integumentary optical properties. Here, we show that vipers (Squamata:Viperidae) inhabiting hot, highly radiative and superficially conductive substrates have evolved bright ventra for efficient heat transfer. We analyzed the brightness of 4161 publicly available images from 126 species, and we found that substrate type, alongside latitude and body mass, strongly influences ventral brightness. Substrate type also significantly affects dorsal brightness, but this is associated with different selective forces: activity-pattern and altitude. Ancestral estimation analysis suggests that the ancestral ventral condition was likely moderately bright and, following divergence events, some species convergently increased their brightness. Vipers diversified during the Miocene and the enhancement of ventral brightness may have facilitated the exploitation of arid grounds. We provide evidence that integument brightness can impact the behavioral ecology of ectotherms., Jonathan Goldenberg et al. use photographic data and ancestral state reconstruction of 126 viper species to show that substrate type influences the evolution of ventral brightness for efficient heat transfer. Their results suggest that these patterns may have been involved in the diversification of vipers during the Miocene, and highlight the importance of ventral body regions when considering behavioral ecology and evolution.

Biodiversity accumulates hierarchically by means of ecological and evolutionary processes and feedbacks. Within ecological communities drift, dispersal, speciation, and selection operate simultaneously to shape patterns of biodiversity. Reconciling the relative importance of these is hindered by current models and inference methods, which tend to focus on a subset of processes and their resulting predictions. Here we introduce Massive Eco-evolutionary Synthesis Simulations (MESS), a unified mechanistic model of community assembly, rooted in classic island biogeography theory, which makes temporally explicit joint predictions across three biodiversity data axes: i) species richness and abundances; ii) population genetic diversities; and iii) trait variation in a phylogenetic context. Using simulations we demonstrate that each data axis captures information at different timescales, and that integrating these axes enables discriminating among previously unidentifiable community assembly models. MESS is unique in generating predictions of community-scale genetic diversity, and in characterizing joint patterns of genetic diversity, abundance, and trait values. MESS unlocks the full potential for investigation of biodiversity processes using multi-dimensional community data including a genetic component, such as might be produced by contemporary eDNA or metabarcoding studies. We combine with supervised machine learning to fit the parameters of the model to real data and infer processes underlying how biodiversity accumulates, using communities of tropical trees, arthropods, and gastropods as case studies that span a range of data availability scenarios, and spatial and taxonomic scales., Funding was provided by grants from FAPESP (BIOTA, 2013/50297-0 to MJH and AC Carnaval), the Synthesis Centre of iDiv (DFG FZT 118), NASA through the Dimensions of Biodiversity Program (DOB 1343578) and the National Science Foundation (DEB-1253710 to MJH; DEB 1745562 to AC Carnaval; DBI 1927319 to AJR). IO was supported by the Mina Rees Dissertation Fellowship in the Sciences provided by the Graduate Center of the City University of New York. MR was supported by the Bioinformatics and Computational Biology Fellowship through the Institute for Bioinformatics and Evolutionary Studies at the University of Idaho. AJR was supported by the Santa Fe Institute Omidyar Fellowship. JR was supported by fellowships from the Natural Environment Research Council (NERC) (NE/I021179, NE/L011611/1). RSE was supported by an NWO-VICI grant. This work is a contribution to Imperial College’s Grand Challenges in Ecosystems and the Environment initiative, through JR.

Understanding the processes that drive diversification of species is essential and urgent. Although detailed data collection and modern genetics have helped enormously in being able to map existing species back to their common ancestor, extinct species are blatantly missing in these analyses, leaving us with only a very partial and biased picture of the extinction process. Nevertheless, extinct species can leave behind a signal in the phylogeny the currently extant species. Over the past decades simple macro-evolutionary models have been proposed for this signal. Unfortunately, these models lack biological plausibility and more complex versions of such models, which incorporate species interactions, are computationally almost intractable, because a coherent description of these interactions results in an extremely large set of coupled differential equations. Moreover, fitting this complex model to the molecular phylogeny of extant species requires integration over a high-dimensional space of partially extinct tree topologies, which is computationally unfeasible with current methods.In this thesis we present a novel quantitative framework, combining statistical methodologies with data augmentation techniques, that allows the integration, combination and incorporation of biological realism into a general class of models making it possible to consider the complexity of ecological interactions. We illustrate our framework by studying novel species diversification models that include dependence of diversification on phylogenetic diversity. We conclude that our methodology has great potential to overcome and quantify a broad variety of hypotheses in theoretical and evolutionary community ecology.

This thesis provides new tools for extracting information on the process of diversification from a phylogenetic tree. To do so the standard approach is to employ likelihood functions in order to estimate the best parameters for the diversification models via likelihood maximization. The parameters for this kind of models usually represent the diversification rates at which the various evolutionary events (e.g., speciations or extinctions) can take place in the process.

Most ecological communities are facing changing environments, particularly due to global climate change. When migration is impossible, adaptation to these altered environments is necessary to survive. Yet, we have little theoretical understanding how ecological communities respond both ecologically and evolutionarily to such environmental change. Here we introduce a simple eco-evolutionary model, the Community-Wide Rescue (CWR) model, in which a community faces environmental deterioration and each species within the community is forced to undergo adaptation or become extinct. We assume that all species in the community are equivalent except for their initial abundance. This individual based simulation model thus combines community ecology and evolutionary rescue theory. We show that under Community-Wide Rescue a rapid loss of rare species occurs. This loss occurs due to competition and a limited supply of beneficial mutations. The rapid loss of rare species provides a testable prediction regarding the impact of Community-Wide Rescue on species abundance distributions in ecological communities.

Vascular epiphytes form a diverse group of almost 30 000 species, yet theory concerning their community structure is still largely lacking. We therefore employed the simplest models of biodiversity, (near-)neutral models, to generate hypotheses concerning their community structure. With recently developed tools for (near-)neutral models we analyzed species abundance data from many samples in Central and South America which we divided into four metacommunities (Mesoamerica, Central America, Amazonia and Paraná), where for each metacommunity we considered two subsets differing in dispersal syndrome: an animal-dispersed guild and a wind-dispersed guild. We considered three models differing in the underlying speciation mode. Across all metacommunities, we found observed patterns to be indistinguishable from patterns generated by neutral or near-neutral processes. Furthermore, we found that subdivision in different dispersal guilds was often supported, with recruitment limitation being stronger for animal-dispersed species than for wind-dispersed species. This is the first time that (near-)neutral theory has been applied to epiphyte communities. Future efforts with additional data sets and more refined models are expected to further improve our understanding of community structure in epiphytes and will have to test the generality of our findings.

Background A central tenet of the evolutionary theory of communities is that competition impacts evolutionary processes such as local adaptation. Species in a community exert a selection pressure on other species and may drive them to extinction. We know, however, very little about the influence of unsuccessful or ghost species on the evolutionary dynamics within the community. Methods Here we report the long-term influence of a ghost competitor on the performance of a more successful species using experimental evolution. We transferred the spider mite Tetranychus urticae onto a novel host plant under initial presence or absence of a competing species, the congeneric mite T. ludeni. Results The competitor species, T. ludeni, unintentionally went extinct soon after the start of the experiment, but we nevertheless completed the experiment and found that the early competitive pressure of this ghost competitor positively affected the performance (i.e., fecundity) of the surviving species, T. urticae. This effect on T. urticae lasted for at least 25 generations. Discussion Our study suggests that early experienced selection pressures can exert a persistent evolutionary signal on species’ performance in novel environments.

Colonization, speciation and extinction are dynamic processes that influence global patterns of species richness1,2,3,4,5,6. Island biogeography theory predicts that the contribution of these processes to the accumulation of species diversity depends on the area and isolation of the island7,8. Notably, there has been no robust global test of this prediction for islands where speciation cannot be ignored9, because neither the appropriate data nor the analytical tools have been available. Here we address both deficiencies to reveal, for island birds, the empirical shape of the general relationships that determine how colonization, extinction and speciation rates co-vary with the area and isolation of islands. We compiled a global molecular phylogenetic dataset of birds on islands, based on the terrestrial avifaunas of 41 oceanic archipelagos worldwide (including 596 avian taxa), and applied a new analysis method to estimate the sensitivity of island-specific rates of colonization, speciation and extinction to island features (area and isolation). Our model predicts—with high explanatory power—several global relationships. We found a decline in colonization with isolation, a decline in extinction with area and an increase in speciation with area and isolation. Combining the theoretical foundations of island biogeography7,8 with the temporal information contained in molecular phylogenies10 proves a powerful approach to reveal the fundamental relationships that govern variation in biodiversity across the planet.

One of the most amazing phenomena in the world is the coexistence of an incredible diversity of species. How and why species have evolved so distinct morphological traits from a common ancestor constantly puzzles biologists. Although substantial details in underlying mechanisms of ecology and evolution remain to be revealed, biotic and abiotic interactions are widely accepted as key drivers. I investigate the influence of species interactions on macroecological and macroevolutionary patterns. I confirmed that species interactions can slow down diversity accumulation if the environment has a limited capacity to host species of the same trophic level. However, spatial geographic structure may reduce the power of current methods to detect local limits to diversification. This result indicates that biologists need to be cautious when using diversity-dependent diversification to explain species assembly. Besides species diversity, species interactions can also influence trait diversity. I use a novel model to explain how trait evolution unfolds under environmental stabilizing selection and species interactions together with population dynamics. This model can potentially lead to novel approaches in phylogenetic comparative methods. Furthermore, I use a simulation model to explore how an ecological hypothesis of species interactions - the phylogenetic Janzen-Connell effect - results in a wide range of realistic macroecological and macroevolutionary community patterns. To summarize, species interactions are the fundamental elements beneath any biological mechanism and require further research to better understand the world we are living in.

In nature different animal species live together in communities. Often these are species that are closely related and ecologically very similar. As such, they usually have very similar needs, and are expected to be competitors, for example with regard to the food they take. So how is it possible that such communities do exist at all, without one successful species outcompeting all the others? To find the answer I studied many complex communities of tens of small land snail species (‘microsnails’) in the tropical lowlands of Malaysian Borneo. I found that the communities are very much closed off, with little exchange of individuals among local communities. Based on a genetic analysis of the plant diet and microbiome from individual snails, I found little correlation between diversity of the diet and the community. However, a more diverse diet is associated with a more diverse microbiome. In addition, I found that, even though most snails have a very diverse plant diet, there’s surprisingly little diet differentiation among species. This suggests that there’s little competition among species within the community. Various theoretical models supported the idea that these complex snail communities are indeed not so much composed based on different species trying to avoid each other (e.g. by choosing a different diet), but instead that the influence of randomness is more important. Therefore, to understand the assembly of complex communities, it is important to first study the influence of stochasticity.

Molecular phylogenies have been increasingly recognized as an important source of information on species diversification. For many models of macroevolution, analytical likelihood formulas have been derived to infer macroevolutionary parameters from phylogenies. A few years ago, a general framework to numerically compute such likelihood formulas was proposed, which accommodates models that allow speciation and/or extinction rates to depend on diversity. This framework calculates the likelihood as the probability of the diversification process being consistent with the phylogeny from the root to the tips. However, while some readers found the framework presented in Etienne et al. (Proc R Soc Lond B Biol Sci 279(1732):1300–1309, 2012) convincing, others still questioned it (personal communication), despite numerical evidence that for special cases the framework yields the same (i.e., within double precision) numerical value for the likelihood as analytical formulas do that were independently derived for these special cases. Here we prove analytically that the likelihoods calculated in the new framework are correct for all special cases with known analytical likelihood formula. Our results thus add substantial mathematical support for the overall coherence of the general framework.

Our world is amazingly heterogeneous; from open landscapes to closed forests, from lowlands to highlands, and from arid plains to swamps. Different species adapt to these different conditions and perform best in that specific environment. But just being adapted to one condition is not enough as the world is also incredibly dynamic, both in space and time. Species may endure these changes, behaviourally adapt or perform some kind of ecosystem engineering. Also genetic adaptation is possible over several generation. In this thesis, I try to untangle which factors may influence adaptation. Understanding when adaptation is more likely to occur is important for conservation purposes or making better predictions. Adaptation is a complex process that is affected by its spatial and community context. By means of experiments with an arthropod model species we investigated this context for adaptation to a novel food source. The spatial context consisted of homo- or heterogeneous environments or differences in dispersal, while the community context included the presence of another species during adaptation or the influence of the present microbiome (micro-organisms assisting their hosts with for instance digestion and detoxification of food). Although I was able to explain more about the influence of dispersal, competition, and the microbiome, it is just a glimpse of what still needs to be discovered.

The protracted speciation model presents a realistic and parsimonious explanation for the observed slowdown in lineage accumulation through time, by accounting for the fact that speciation takes time. A method to compute the likelihood for this model given a phylogeny is available and allows estimation of its parameters (rate of initiation of speciation, rate of completion of speciation and extinction rate) and statistical comparison of this model to other proposed models of diversification. However, this likelihood computation method makes an approximation of the protracted speciation model to be mathematically tractable: it sometimes counts fewer species than one would do from a biological perspective. This approximation may have large consequences for likelihood-based inferences: it may render any conclusions based on this method completely irrelevant. Here, we study to what extent this approximation affects parameter estimations. We simulated phylogenies from which we reconstructed the tree of extant species according to the original, biologically meaningful protracted speciation model and according to the approximation. We then compared the resulting parameter estimates. We found that the differences were larger for high values of extinction rates and small values of speciation-completion rates. Indeed, a long speciation-completion time and a high extinction rate promote the appearance of cases to which the approximation applies. However, surprisingly, the deviation introduced is largely negligible over the parameter space explored, suggesting that this approximate likelihood can be applied reliably in practice to estimate biologically relevant parameters under the original protracted speciation model.

Previous investigations of the systematics of Neotropical pipits Anthus revealed multiple cases of paraphyly. We revise the species limits of this group based on sequence data of mitochondrial (ND2) and nuclear genes (ACOI9, MB, FGB5) from 39 tissue samples of all 22 subspecies-level taxa in the New World Anthus clade, as well as analysis of display song. We found that Anthus lutescens peruvianus is not part of Yellowish Pipit Anthus lutescens genetically or vocally; thus, we elevate peruvianus to species rank (Peruvian Pipit). Anthus lutescens abariensis Chubb (1921a) should be placed in synonymy with A. l. parvus (instead of A. l. lutescens), at least until further morphological or vocal data becomes available. Paramo Pipit A. bogotensis is likewise paraphyletic, with meridae sister to all other bogotensis subspecies and also to Hellmayr's Pipit A. hellmayri. However, placement of the taxon is based on a relatively short stretch of mitochondrial DNA, and further data are needed. Andean populations of Short-billed Pipit A. furcatus are split as Puna Pipit A. brevirostris, based on genetic and vocal data. South Georgia Pipit A. antarcticus is, at least genetically, part of Correndera Pipit A. correndera, and we recommend considering it a subspecies of Correndera Pipit, in line with the taxonomy of other morphologically distinct but genetically little-differentiated insular bird taxa. This article is protected by copyright. All rights reserved.

Community composition reflects evolutionary and ecological processes such as diversification and species assortment. Communities are generally considered to be saturated, which means that the number of species is maximized and that regulatory mechanisms, such as interspecific competition, prevent the addition of new species. In the tropics, however, species numbers of local bird assemblages double up each winter after the arrival of migratory species, which suggests that a rearrangement of niches occurs. Here ecological space is defined by morphological traits that reflect the ecological position of species, to describe changes in the structure of local communities. We found that the average morphological distance between species was reduced, and the volume (the total extent of trait space) was expanded with the arrival of migrants, indicating that newcomers occupy the periphery and the interior of the available ecological space. Furthermore, with greater morphological differences between resident species, higher numbers of migratory species can take advantage of free space and potentially exploit unused resources due to their intermediate morphology. We highlight the differences in the attributes of resident versus migratory species that may allow both to he accommodated in the morphological space, and we suggest coexistence theory as a possible explanation for the co-occurrence of similar species. (C) 2017 Gesellschaft fur Okologie. Published by Elsevier GmbH. All rights reserved.

Summary Half a century ago, MacArthur and Wilson proposed that the number of species on islands tends toward a dynamic equilibrium diversity around which species richness fluctuates [1]. The current prevailing view in island biogeography accepts the fundamentals of MacArthur and Wilson's theory [2] but questions whether their prediction of equilibrium can be fulfilled over evolutionary timescales, given the unpredictable and ever-changing nature of island geological and biotic features [3–7]. Here we conduct a complete molecular phylogenetic survey of the terrestrial bird species from four oceanic archipelagos that make up the diverse Macaronesian bioregion—the Azores, the Canary Islands, Cape Verde, and Madeira [8, 9]. We estimate the times at which birds colonized and speciated in the four archipelagos, including many previously unsampled endemic and non-endemic taxa and their closest continental relatives. We develop and fit a new multi-archipelago dynamic stochastic model to these data, explicitly incorporating information from 91 taxa, both extant and extinct. Remarkably, we find that all four archipelagos have independently achieved and maintained a dynamic equilibrium over millions of years. Biogeographical rates are homogeneous across archipelagos, except for the Canary Islands, which exhibit higher speciation and colonization. Our finding that the avian communities of the four Macaronesian archipelagos display an equilibrium diversity pattern indicates that a diversity plateau may be rapidly achieved on islands where rates of in situ radiation are low and extinction is high. This study reveals that equilibrium processes may be more prevalent than recently proposed, supporting MacArthur and Wilson's 50-year-old theory.

Islands are at the frontline of the anthropogenic extinction crisis [1]. A vast number of island birds have gone extinct since human colonization [2], and an important proportion is currently threatened with extinction [3]. While the number of lost or threatened avian species has often been quantified [4], the macroevolutionary consequences of human impact on island biodiversity have rarely been measured [5]. Here, we estimate the amount of evolutionary time that has been lost or is under threat due to anthropogenic activity in a classic example, New Zealand. Half of its bird taxa have gone extinct since humans arrived [6, 7] and many are threatened [8], including lineages forming highly distinct branches in the avian tree of life [9-11]. Using paleontological and ancient DNA information, we compiled a dated phylogenetic dataset for New Zealand's terrestrial avifauna. We extend the method DAISIE developed for island biogeography [12] to allow for the fact that many of New Zealand's birds are evolutionarily isolated and use it to estimate natural rates of speciation, extinction, and colonization. Simulating under a range of human-induced extinction scenarios, we find that it would take approximately 50 million years (Ma) to recover the number of species lost since human colonization of New Zealand and up to 10 Ma to return to today's species numbers if currently threatened species go extinct. This study puts into macroevolutionary perspective the impact of humans in an isolated fauna and reveals how conservation decisions we take today will have repercussions for millions of years.

Aim: Islands are often hotspots of endemism due to their isolation, making colonization a rare event and hence facilitating allopatric speciation. Dispersal usually occurs between nearby locations according to a stepping-stone model. We aimed to reconstruct colonization and speciation processes in an endemic-rich system of land-based islands that does not seem to follow the obvious stepping-stone model of dispersal.Location: Five land-based habitat archipelagos of limestone outcrops in the flood-plain of the Kinabatangan River in Sabah, Malaysian Borneo.Methods: We studied the phylogeography of three species complexes of endemic land snails, using multiple genetic markers. We calculated genetic distances between populations, applied beast2 to reconstruct phylogenies for each taxon and subsequently reconstructed ancestral ranges using 'BioGeoBEARS'.Results: We found spatial-genetic structure among nearby locations to be highly pronounced for each taxon. Genetic correlation was present at small spatial scales only and disappeared at distances of 5 km and above. Most archipelagos have been colonized from within the region multiple times over the past three million years, in 78% of the cases as a result of long-distance dispersal (LDD) or dispersal from non-adjacent limestone outcrops. The flow of the main geographical feature within the region, the Kinabatangan River, did not play a role.Main conclusions: Phylogeographic structure in these Bornean land snails has only partly been determined by small-scale dispersal, where it leads to isolation-by-distance, but mostly by LDD. Our results demonstrate that island endemic taxa only very locally follow a simple stepping-stone model, whilst dispersal to non-adjacent islands and especially LDD, is most important. This leads to the formation of highly localized, isolated " endemic populations" forming the onset of a complex radiation of endemic species.

The Bornean representatives of the genus Georissa (Hydrocenidae) have small, dextral, conical, calcareous shells consisting of ca. three teleoconch whorls. Our recent study on the Georissa of Malaysian Borneo has revealed high intra- and inter-specific variation in the “scaly” group (a group of species with striking scale-like surface sculpture). The present study on the “non-scaly” Georissa is the continuation of the species revision for the genus. The “non-scaly” species are also diverse in shell sculptures. This informal group comprises Georissa with subtle spiral and/or radial sculpture. The combination of detailed conchological assessment and molecular analyses provides clear distinctions for each of the species. Conchological, molecular, and biogeographic details are presented for 16 species of “non-scaly” Georissa. Three of these are new to science, namely Georissacorrugatasp. n., Georissainsulaesp. n., and Georissatrusmadisp. n.

Oceanic islands are not static entities; instead, their size and features change dynamically through time, a process called island ontogeny. It has been hypothesized that the gradual or at times abrupt changes an island experiences during its lifespan can have a strong effect on the composition and evolution of biological communities. The general dynamic model of island biogeography assumes that island area and topographic complexity change through time and influence the number of available niches, and thus rates of diversification. A previous study demonstrated the role of single-island ontogeny on the Hawaiian biota, but most diversification studies on islands have not considered it. We tested under what conditions island ontogeny can bias diversification studies if not taken into account, using a simulation approach based on an extended version of the phylogenetic framework DAISIE. We simulated evolution on islands subject to ontogenetic processes and attempted to infer the generating parameters using existing methods that ignore ontogeny. Furthermore, we assessed how reasonable predictions of future biodiversity that ignore past island ontogeny are. Our analyses allow us to lay out guidelines on how and when to incorporate island geomorphological data into island phylogenetic diversification studies. This will lead to more robust conclusions about the origin and maintenance of biodiversity on oceanic islands.