Northwestward range expansion of the bumblebee Bombus haematurus into Central Europe is associated with warmer winters and niche conservatism

Species range expansions are crucial for understanding niche formation and the interaction with the environment.Here,we studied the bumblebee Bombus haematurus Kriechbaumer,1870,a species historically distributed from northern Serbia through northern Iran which has very recently started expanding northwestward into Central Europe without human-mediated dispersal(i.e.,it is a natural spread).After updating the global distribution of this species,we investigated if niche shifts took place during this range expansion between newly colonized and historical areas.In addition,we have explored which climatic factors may have favored the natural range expansion of the species.Our results indicated that Bombus haematurus has colonized large territories in 7 European countries outside the historical area in the period from the 1980s to 2018,a natural expansion over an area that equals 20%of the historical distribution.In addition,this bumblebee performs generalism in flower visitation and it occurs in different habitats,although a preference for forested areas clearly emerges.The land-use associated with the species in the colonized areas is similar to the historical distribution,indicating that no major niche shifts occurred during the spread.Furthermore,in recently colonized localities,the range expansion was associated with warming temperatures during the winter and also during both queen overwintering and emergence phases.These findings document a case of natural range expansion due to environmental change rather than due to niche shifts,and specifically they suggest that warmer winters could be linked to the process of natural colonization of new areas.

Limiting climatic factors in shaping the distribution pattern and niche differentiation of Prunus dielsiana in subtropical China

Subtropical forest in China has received much attention due to its complex geologic environment and bioclimatic heterogeneity.There have been very few studies addressing which climatic factors have shaped both distribution patterns and niche differentiation of species from this region.It also remains unclear whether phylogenetic niche conservatism retains in plant species from this biodiversityrich subtropical region in China.In this study,we used geographic occurrence records and bioclimatic factors of Prunus dielsiana(Rosaceae),a wild cherry species,combined with the classical ENM-based DIVA-GIS software to access contemporary distribution and richness patterns of its natural populations.The current distribution of P.dielsiana occupied a relatively wide range but exhibited an uneven pattern eastward in general,and the core distribution zone of its populations are projected to concentrate in the Wushan and Wuling Mountain ranges of western China.Hydrothermic variables,particularly the Temperature Seasonality(bio4)are screened out quantitatively to be the most influential factors that have shaped the current geographical patterns of P.dielsiana.By comparison with other sympatric families,climatic niche at regional scale showed a pattern of phylogenetic niche conservatism within cherry species of Ros aceae.The effect of habitat filtering from altitude is more significant than those of longitude and latitude.We conclude that habitat filtering dominated by limiting hydrothermic factors is the primary driving process of the diversity pattern of P.dielsiana in subtropical China.

Lineage Diversification and Niche Evolution in the Chinese Cobra Naja atra (Elapidae)

Theroleof nicheevolution(niche conservatism or niche divergence)in lineage diversification is a poorly studied area.The Chinese cobra Naja atra(Elapidae)has diverged into three lineages:Lineage E in eastern China,Lineage S in southern China and Vietnam,and Lineage W in western China.However,whether the ecological niche is conserved or divergent among these three lineages is unknown.In the present study,we used ecological niche models in geographical space to study the ecological differences among lineages.We compared the niche overlap in environmental space to test niche conservatism and niche divergence.Our results showed that the three lineages of N.atra shared an ecological niche space between Lineages E and S/W,with the climatic niches of Lineages S and W representing a specialized fraction of the climatic niche of Lineage E.We speculated that the niche divergence between Lineages S and W was a consequence of geographical barriers limitinggeneflow.Ourstudyprovides evidence for lineage diversification associated with both geographical isolation and climatic niche evolution,suggesting that early niche divergence between Lineages S and W,followed by niche conservatism,causes niche divergence among lineages.

Genomic data and ecological niche modeling reveal an unusually slow rate of molecular evolution in the Cretaceous Eupteleaceae

Living fossils are evidence of long-term sustained ecological success.However,whether living fossils have little molecular changes remains poorly known,particularly in plants.Here,we have introduced a novel method that integrates phylogenomic,comparative genomic,and ecological niche modeling analyses to investigate the rate of molecular evolution of Eupteleaceae,a Cretaceous relict angiosperm family endemic to East Asia.We assembled a high-quality chromosome-level nuclear genome,and the chloroplast and mitochondrial genomes of a member of Eupteleaceae(Euptelea pleiosperma).Our results show that Eupteleaceae is most basal in Ranunculales,the earliest-diverging order in eudicots,and shares an ancient whole-genome duplication event with the other Ranunculales.We document that Eupteleaceae has the slowest rate of molecular changes in the observed angiosperms.The unusually low rate of molecular evolution of Eupteleaceae across all three independent inherited genomes and genes within each of the three genomes is in association with its conserved genome architecture,ancestral woody habit,and conserved niche requirements.Our findings reveal the evolution and adaptation of living fossil plants through large-scale environmental change and also provide new insights into early eudicot diversification.

Old climatically-buffered infertile landscapes(OCBILs):more than harsh habitats,Atlantic Forest inselbergs can be drivers of evolutionary diversity

Granite-gneiss rock outcrop inselbergs are ancient stable ecosystems with old,climaticallybuffered infertile landscapes(OCBILs).Although inselbergs provide key ecosystem services,little is done for their conservation and,so far,a lot of their unknown evolutionary history has already been lost by human activities.Using a fine-scale approach,here we tested if habitat and environmental filtering(the inselberg’s harshness)affect the evolutionary diversity of an Atlantic Forest inselberg in Brazil.We recorded all trees with a diameter at breast height≥5cm in 20 plots in four habitat types(total sampled area of 0.8 hectares),from highest to lowest:island,hillside,foothill,and semideciduous forest(matrix).We also collected soil samples for chemical,textural and physical soil characterization.We fitted linear models to test the effects of soil and habitat on plotlevel metrics of phylogenetic diversity and structure,lineage diversity,phylogeneticβ-diversity,and evolutionary distinctiveness.We found that the upper inselberg habitats contain a distinct set of ancient,closely related,harsh-tolerant lineages,as well as a subset of lineages that persist under harsh conditions with a certain degree of water availability.The inferior inselberg habitats harbor higher lineage diversity than expected by chance.Soil strongly predicted evolutionary diversity.We concluded that soil depth,slope,nutrients and texture(environmental filtering)and habitat types and topography(habitat filtering)shape the evolutionary history contained in fine-scale inselberg habitats,which should encourage the conservation of these ancient ecosystems.

Complex patterns of environmental niche evolution in Iberian columbines (genus Aquilegia, ranunculaceae)

Aims This study explores the patterns of niche differentiation in a group of seven closely related columbines(genus Aquilegia,ranunculaceae)from the Iberian Peninsula.Populations of these columbines are subject to complex patterns of divergent selection across environ-ments,which partly explain the taxonomic structure of the group.This suggests the hypothesis that niche divergence must have occurred along the process of diversification of the group.Methods We used maxEnt to build environmental niche models of seven subspecies belonging to the three species of Aquilegia present in the Iberian Peninsula.From these models,we compared the envi-ronmental niches through two different approaches:ENmtools and multivariate methods.Important FindingsmaxEnt distributions conformed closely to the actual distribution of the study taxa.ENmtools methods failed to uncover any clear patterns of niche differentiation or conservatism in Iberian columbines.multivariate analyses indicate the existence of dif-ferentiation along altitudinal gradients and along a gradient of climatic conditions determined by the summer precipitation and temperatures.However,climatic conditions related to winter tem-perature and precipitation,as well as soil properties,were equally likely to show conservatism or divergence.The complex patterns of niche evolution we found suggest that Iberian Columbines have not been significantly constrained by forces of niche conservatism,so they could respond adaptively to the fast and profound climate changes in the Iberian Peninsula through the glacial cycles of the Pleistocene.

Lineage diversification and niche evolution in the Reeves’Butterfly Lizard Leiolepis reevesii(Agamidae)

We used mitochondrial cytochrome b and ND4 genes and 9 microsatellite loci to determine genetic diversity,population structure,evolutionary history,and migration patterns within the Reeves’butterfly lizard Leiolepis reevesii(Agamidae).Considering molecular-based phylogeographical lineages,we then performed niche equivalency and similarity tests between divergent lineages.Phylogenetic analyses based on mitochondrial DNA(mtDNA)data revealed 2 lineages(A and B)diverging≈0.84 million years ago and,respectively,restricted to the northern and southern portions of the Wuzhishan and Yinggeling mountain ranges.Lineage B contains individuals from southern Hainan;Lineage A includes individuals from all other localities and can be further divided into 3 clusters according to microsatellite data.The null hypothesis that the 2 lineages shared identical niches was rejected in all niche equivalency tests,indicating niche shifts during genetic divergence.Similarity tests provided evidence of niche conservatism,suggesting that the 2 lineages share more characteristics of their niche spaces than randomly expected.The niche similarity and equivalency tests indicated a complex niche pattern in which both lineages share a main portion of their ecological spaces.The climatic niche of Lineage B represented a marginal and specialized fraction of the entire ecological space of the climatic niche of Lineage A,with warmer conditions.Isolation caused by orogenesis and subsequent niche divergence,together with local adaptation,may have led to genetic differentiation and further lineage sorting in L.reevesii.

Climatic correlates of phylogenetic relatedness of woody angiosperms in forest communities along a tropical elevational gradient in South America

Aims This study assesses the relationship between phylogenetic relat-edness of angiosperm tree species and climatic variables in local forests distributed along a tropical elevational gradient in South America.In particular,this paper addresses two questions:Is phylo-genetic relatedness of plant species in communities related to tem-perature variables more strongly than to water variables for tropical elevational gradients?Is phylogenetic relatedness of plant species in communities driven by extreme climatic conditions(e.g.minimum temperature(MT)and water deficit)more strongly than by climatic seasonal variability(e.g.temperature seasonality and precipitation seasonality)?Methods I used a set of 34 angiosperm woody plant assemblages along an elevational gradient in the Andes within less than 5 degrees of the equator.Phylogenetic relatedness was quantified as net relatedness index(NRI)and nearest taxon index(NTI)and was related to major climatic variables.Correlation analysis and structure equation modeling approach were used to assess the relationships between phylogenetic relatedness and climatic variables.Important Findings Phylogenetic relatedness of angiosperm woody species in the local forest communities is more strongly associated with temperature-related variables than with water-related variables,is positively cor-related with mean annual temperature(MAT)and MT,and is related with extreme cold temperature more strongly than with seasonal temperature variability.NTI was related with elevation,MAT and MT more strongly than was NRI.Niche convergence,rather than niche conservatism,has played a primary role in driving community assem-bly in local forests along the tropical elevational gradient examined.Negative correlations of phylogenetic relatedness with elevation and higher correlations of phylogenetic relatedness with elevation and temperature for NTI than for NRI indicate that evolution of cold toler-ance at high elevations in tropical regions primarily occurred at recent(terminal)phylogenetic nodes widely distributed among major clades.

Latitudinal and elevational patterns of phylogenetic structure in forest communities in China’s mountains

The phylogenetic structure incorporates both ecological and evolutionary processes to explain assembly of a local community.The "phylogenetic niche conservatism"(PNC) hypothesis suggests that distributions of species along environmental gradients reflect both ancestral traits and ecological fitness of individual species. The temperature is generally regarded to change in similar ways along both latitudinal and elevational gradients but with different historical contingence. Therefore, comparing the latitudinal and elevational patterns of phylogenetic structure of communities is of help to depict the effects of ecological and evolutionary processes in shaping the community assembly. In this study, we explored the latitudinal, elevational and climatic patterns of phylogenetic structure of 569 angiosperm tree communities from 38 mountains across China. We found a larger mean abundance-weighted net relatedness index(NRI) than the presence/absence-based NRI;and the NRI decreased when the species pool downscaled from the full pool to county-level pool. The mean family age and phylogenetic species evenness decreased with latitude, and increased with temperature of the coldest month and precipitation;whilst NRI increased with latitude, and decreased with mean temperature of the coldest month. In most mountains, NRI, mean family age and phylogenetic species evenness showed non-significant trends along the elevational gradient. Our results support the main predictions of PNC for the latitudinal gradient, i.e., species tend to be more phylogenetically related to each other and clades are younger in temperate environments,compared to those in tropical environments. We suggested that independent species pools and abundance should be incorporated in analysis to fully represent the phylogenetic structure of communities.

Relationship between clade age and temperature for angiosperm tree species in forest communities along an elevational gradient in tropical Asia

Aims The tropical conservatism hypothesis(TCH)links environmental tolerance,diversification,dispersal and evolutionary history in explaining why warm,wet tropical regions harbor more species than colder,drier regions.The TCH is considered as a dominant explanation for broad-scale patterns of species richness across the globe,such as the latitudinal diversity gradient.At its core,the TCH predicts a positive relationship between clade age and tempera-ture.Here,I test this prediction using a data set of angiosperm tree assemblages from Malesia.Methods I assembled an altitudinal gradient of 15 communities of angio-sperm trees.I calculated the mean family age(MFA)of tree species for each community.I used ordinary regression analysis and spatial autoregression analysis to determine the relationships of species richness and MFA with elevation,temperature and precipitation.I used correlation analysis to assess relationships between paired variables.Important Findings MFA is negatively correlated with tree species richness,and increases with elevation and decreases with temperature for the alti-tudinal gradient.MFA remains significantly increasing with decreas-ing temperature along the altitudinal gradient after accounting for spatial autocorrelation in a species-ordination space.The negative relationship between clade age and temperature along the altitudi-nal gradient in Malesia is contrary to the TCH.

Linking the past and present to predict the distribution of Asian crested ibis(Nipponia nippon)under global changes

Understanding how species’ecological niches adapt to environmental changes through time is critical for predicting the effect of future global change on endangered species.Yet few studies have incorporated knowledge of past niche shifting into the assessment of species’future fate in a changing world.In this study,we integrated the ecological niche dynamics into the species distribution modeling of the Asian crested ibis(Nipponia nippon)in East Asia.Specifically,we compared historical and present ecological niches of crested ibis in four-dimensional environmental space based on species occurrence and environmental data.We then employed a multi-temporal ecological niche model to estimate the potential geographical distribution of crested ibis under future climate and land-use changes.Our results show that crested ibis retained similar though not identical ecological niches over time.Compared to the historical baseline range,the current suitable habitat for crested ibis has been reduced by 39.6%.The effects of human activity outweigh those of climate change regarding the distribution of crested ibis.We conclude that the ecological niche of crested ibis was tended to be conservative,and future potentially suitable habitat may encounter northeastward and northwestward shift,and possibly expand by 18.7%referred to the historical range.Thefindings of our study are of clear importance for the conservation and successful reintroduction of crested ibis in East Asia.