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Aim: Species are largely thought to maintain broadly static niches over time, an assumption underpinning much theoretical ecology including the implementation of ecological models to project species' current and future distributions. Here, we assess niche conservatism in odonates in Great Britain over the past six decades by simultaneously quantifying changes in species geographic distribution and evaluating temporal trends in species realised climatic niche. Location: Great Britain. Methods: Distributional changes were assessed by calculating changes in species distribution centres and deriving occupancy trends. Changes in climatic niches were assessed using a principal component analysis to quantify niche overlap, using information on both climate averages and extremes. Results: We show that dragonflies and damselflies displayed distinct responses to changing climatic conditions. Dragonflies shifting to higher latitudes maintained, on average, greater consistency in their climatic niches, providing evidence for climate tracking. Greater climate niche flexibility and increased occupancy over time, on the other hand, were more common in damselflies. Main Conclusions: We unveil evidence for climatic niche divergence in damselflies on a national scale, casting doubt on the relevance of species distribution models for predicting the impacts of climate change on this, and potentially other, groups of species. More broadly, our results call for more multi‐species temporal comparisons of spatial distributions and climate niches during recent periods of changes in climatic conditions to improve our ability to contrast species' vulnerability risk to the ongoing climate crisis. [ABSTRACT FROM AUTHOR]

The relict genus Paradactylodon is narrowly distributed in temperate forests throughout the Middle East region, including P. mustersi in Afghanistan, P. persicus , and P. gorganensis in northwestern and northeastern Iran. Recent phylogenetic analyses suggest that the Iranian Paradactylodon populations may belong to a single species, P. persicus. In this study, we addressed how climatic niche conservatism and/or niche divergence may have affected the evolution of all Paradactylodon species using ecological niche models and multivariate niche analyses to identify niche overlap and assess equivalency and similarity tests. We also used an ensemble of ten algorithms to predict Paradactylodon species distributions for recent (1970-2000) and future (2081-2100) climate conditions. The results show that future climate change may cause the loss of 80 to 97% of these species' suitable habitat, especially at lower elevations. The niche divergence hypothesis was supported by the results of niche equivalency tests on P. persicus vs. P. gorganensis (and vice versa) with moderate overlap (D = 0.23, I = 0.41) and P. persicus vs. P. mustersi (and vice versa) with little overlap (D = 0.05, I = 0.06). Meanwhile, the niche similarity test for the niche conservatism hypothesis revealed significant results for P. persicus vs. P. gorganensis , P. mustersi vs. P. persicus , and P. persicus + P. gorganensis (as a single species) vs. P. mustersi. Due to these complex evolutionary ecological patterns and allopatric distributions, we recommend that P. gorganensis be considered a valid subspecies. [ABSTRACT FROM AUTHOR]

As environmental conditions change over time, some species can follow the spatial footprint of their ecological niches or can adapt physiologically to the new conditions; modifying behavior can offer an alternative means of adapting to novel environments. The burrowing habit allows organisms to avoid adverse climatic conditions during part of the year by remaining inside burrows. Smilisca fodiens and S. dentata are two burrowing hylid frogs that inhabit areas beyond the northernmost distributional limits of the other six arboreal species of their genus, and indeed beyond of most American hylids. In this study, we tested whether burrowing habit allows these species to adapt to drier conditions while conserving the climatic niche of the arboreal species. We compared the annual niches of the arboreal species to those of the burrowing species under two assumptions: true seasonal niches and full annual niches. Through ecological niche similarity tests, we performed 24 comparisons in both geographic and environmental spaces. In geographic space, when considering burrowing annual niches, only five of 24 tests indicated similarity, yet as regards seasonal niche, 18 of 24 tests indicated similarity. In environmental space, all tests failed to reject null hypotheses. The analyses showed clearly that burrowing and arboreal species were closer in environmental space when seasonal niches of the burrowing species were used, rather than annual niches. That is, climatic conditions in seasonal niches of burrowing species resemble the annual niches of arboreal species, supporting the proposition that reduction of activity to certain periods of the year is a strategy in burrowing species to conserve their tropical niches while living in dry regions.

Given the high degrees of adaptation to specific microhabitats and restricted-range endemism, Goniurosaurus (Tiger geckos) serves as a unique model to study the complex evolution in lizards. Using phylogenetic analyses, we estimated the first divergence date of Goniurosaurus to the Eocene (~ 45.3 mya). The diversification within four monophyletic species groups began in the mid-Miocene between ~ 13.4 and 7.7 mya and continued to at least the early Pleistocene (~ 2 mya). Their ancestor was predicted to originate somewhere in contiguous continental Eastern Asia, whereas the current regions in which each monophyletic Goniurosaurus species group radiated are respectively their own ancestral regions. Together with factors of altitudinal gradient and climate conditions, we reconstructed relevant niche models of Goniurosaurus including ancestral reconstructions. Consequently, low elevations were predicted to be the most probable ancestral state for Goniurosaurus and all its groups as well. Both climatic niche conservatism and divergence have shaped the extraordinary species richness of allopatric Chinese and Vietnamese tiger geckos. In terms of endangerment, Goniurosaurus has been considered one of the most susceptible lizard groups under severe human impacts, especially climate change. The assessments of their niche evolution can provide a science-based pre-signal of vulnerability, thereby improving the efficacy of conservation measures to safeguard species of Goniurosaurus in the future. Accordingly, almost all closely related species of Goniurosaurus in China and Vietnam were identified with a high rate of niche conservatism, which should be included in conservation priorities under potential impacts of climate change. [ABSTRACT FROM AUTHOR]

Here, we explored how variations in the allopatric speciation scenario, specifically ecological vs. vicariant allopatry, relate to climatic niche change in sister species. We selected two sister species pairs of North American hummingbirds (Calypte anna, C. costae , Basilinna leucotis, B. xantusii) that diverged 2.5 and 3.6 million years ago, under ecological (arid climate tendency during Pliocene) and vicariant (Baja California peninsula separation) allopatric processes, respectively. We constructed the climatic niche of each species using occurrence records and estimated the distance, similarity, and unique fraction of climatic niche between sister species. Calypte species showed moderate niche divergence (Euclidean distance between centroids = 1.94, Sørensen index of similarity = 0.080, unique fraction of hypervolume in C. costae = 0.57, and C. anna = 0.95). However, contrary to expectations, Basilinna species, which diverged under a vicariant scenario, displayed clear niche divergence (Euclidean distance between centroids = 3.78, Sørensen index of similarity = 0.0001, and unique fraction of hypervolume in B. xantusii = 0.98, and B. leucotis = 0.99). We explained dissimilarity in climatic niches between Basilinna species by the ecological divergence between habitats of disjunct populations, which would have also been associated with increased aridity during the Pliocene. [Display omitted] • Type of allopatry affects the degree of niche conservatism in the speciation process. • We tested it in hummingbirds speciation under geographical and ecological allopatry. • Soft ecological allopatry in Calypte species led to expected niche divergence. • Hard geographical allopatry in Basilinna species led to unexpected niche divergence. • Environmental changes in the Pliocene and niche truncation may explain these patterns. [ABSTRACT FROM AUTHOR]

Despite the assessment of long-term niche dynamics could provide crucial information for investigating species responses to environmental changes, it is a poorly investigated topic in ecology. Here, we present a case study of multi-species niche analysis for 71 common breeding birds in Northern Italy, exploring long-term niche changes from 1992 to 2017 and their relationship with both population trends and species traits. We (i) quantified the realized Grinnellian niche in the environmental space, (ii) compared variations in niche breadth and centroid, (iii) tested niche divergence and conservatism through equivalency and similarity tests, (iv) calculated niche temporal overlap, expansion and unfilling indices, and (v) investigated their association with both population changes and species traits. Results supported niche divergence (equivalency test) for 32% of species, although two-thirds were not supported by the similarity test. We detected a general tendency to adjust the niche centroids towards warmer thermal conditions. Increasing populations were positively correlated with niche expansion, while negatively correlated with niche overlap, albeit at the limit of the significance threshold. We found moderate evidence for a non-random association between niche changes and species traits, especially for body size, clutch size, number of broods per year, inhabited landscape type, and migration strategy. We encourage studies correlating long-term population trends and niche changes with species traits’ information and a specific focus on cause-effect relationship at both the single and multiple-species level.

Defining appropriate null expectations for species distribution hypotheses is important because sampling bias and spatial autocorrelation can produce realistic, but ecologically meaningless, geographic patterns. Generating null species occurrences with similar spatial structure to observed data can help overcome these problems, but existing methods focus on single or pairs of species and do not incorporate between‐species spatial structure that may occlude comparative biogeographic analyses. Here, we describe an algorithm for generating randomised species occurrence points that mimic the within‐ and between‐species spatial structure of real datasets and implement it in a new R package – fauxcurrence. The algorithm can be implemented on any geographic domain for any number of species, limited only by computing power. To demonstrate its utility, we apply the algorithm to two common analysis‐types: testing the fit of species distribution models (SDMs) and evaluating niche‐overlap. The method works well on all tested datasets within reasonable timescales. We found that many SDMs, despite a good fit to the data, were not significantly better than null expectations and identified only two cases (out of a possible 32) of significantly higher niche divergence than expected by chance. The package is user‐friendly, flexible and has many potential applications beyond those tested here, such as joint SDM evaluation and species co‐occurrence analysis, spanning the areas of ecology, evolutionary biology and biogeography. [ABSTRACT FROM AUTHOR]

Simple Summary: Temporal changes of ecological niches in relation to both population trends and species traits (life-history and ecological characteristics) are a poorly investigated topic in animal ecology even though they can provide crucial information for investigating how species respond to ongoing environmental changes. To fill this gap, we assessed niche changes from 1992 to 2017 for 71 common breeding birds in Northern Italy, using several niche metrics and relating them with both population trends and species traits. Our results showed that 32% of the species tended to change their niche in relation to the accessible environmental conditions. We found a tendency to adjust the niche towards warmer thermal conditions. This process may depend on several drivers, which act differently across species. Species undergoing a niche expansion showed increasing populations, while species tending to retain their niche showed a tendency to be associated with decreasing populations. We also found evidence for a non-random association between niche temporal changes and species traits. Investigating these relationships is a pivotal point to implement effective conservation strategies for wildlife. Despite the assessment of long-term niche dynamics could provide crucial information for investigating species responses to environmental changes, it is a poorly investigated topic in ecology. Here, we present a case study of multi-species niche analysis for 71 common breeding birds in Northern Italy, exploring long-term niche changes from 1992 to 2017 and their relationship with both population trends and species traits. We (i) quantified the realized Grinnellian niche in the environmental space, (ii) compared variations in niche breadth and centroid, (iii) tested niche divergence and conservatism through equivalency and similarity tests, (iv) calculated niche temporal overlap, expansion and unfilling indices, and (v) investigated their association with both population changes and species traits. Results supported niche divergence (equivalency test) for 32% of species, although two-thirds were not supported by the similarity test. We detected a general tendency to adjust the niche centroids towards warmer thermal conditions. Increasing populations were positively correlated with niche expansion, while negatively correlated with niche overlap, albeit at the limit of the significance threshold. We found moderate evidence for a non-random association between niche changes and species traits, especially for body size, clutch size, number of broods per year, inhabited landscape type, and migration strategy. We encourage studies correlating long-term population trends and niche changes with species traits' information and a specific focus on cause-effect relationship at both the single and multiple-species level. [ABSTRACT FROM AUTHOR]

Different groups of taxa exhibit varying degree of climatic niche conservatism or divergence due to evolutionary constraints imposed on taxa and distributional relationships among them. Herein, we explore to what extent regional environmental conditions that taxa occupy affect climatic niche overlap between pairs of congeneric species of Peromyscus mice exhibiting allopatric, parapatric, or sympatric distributions. We used Bayesian generalized linear mixed models to identify environmental variables that best explain differences in climatic niche overlap between species. Our results suggest that regional environmental conditions explain 13–44% of variation in climatic niche overlap. Specifically, allopatric and parapatric species pairs are more likely to occupy similar climatic niches in areas that are topographically less complex but with more complex habitats. Sympatric species are more likely to occupy similar climatic niches in areas that promote local niche partitioning (topographically less complex, warmer winter temperatures, higher precipitation, and higher habitat complexity on a local scale). By understanding the relationship between regional environmental conditions and niche overlap, we highlight how differences in geography can contribute to shaping niches of congeneric species. [ABSTRACT FROM AUTHOR]

Aim: Understanding the degree to which closely related taxa diverge in their niche traits could provide insight on their evolutionary patterns, as well as shed some light on the mechanisms underpinning broad‐scale biogeographic patterns. The evolution of ticks was thought to be driven by hosts. However, recent evidence suggests that tick evolution is more likely to be driven by habitat conditions. The Amblyomma maculatum group of ticks provides a good example to test the former, as its incipient speciation raises the possibility of a very rapid adaptation to slightly different environments. Location: The Americas. Taxa: Ticks from the Amblyomma maculatum Koch, 1844 (Acari: Ixodidae) group (A. tigrinum, A. triste s.s., A. maculatum s.s. and two intermediate morphs). Methods: We addressed the question of whether the differentiation of taxa within this group results from ecological factors, either maintaining a similar ecological niche (conservatism) or by occupying distinct niches (divergence). We analysed the distribution of each tick morphotype with ecological niche models. Next, we explored the question of whether these closely related taxa inhabit environments that are more different or more similar than expected by comparing niche overlap in environmental space. Results: We found evidence for niche differentiation, showing that the members of the Amblyomma maculatum group exist in and respond to aspects of different environments, leading to geographical variation. Main conclusions: The analysis of the ecological niches of the Amblyomma maculatum group of ticks indicates niche conservatism for the pairs A. tigrinum—A. maculatum s.s. and A. triste s.s.—A. maculatum s.s, traditionally associated to allopatric speciation; while incipient niche divergence is suggested for the remaining comparisons. These findings add additional evidence to the study of the evolution of ticks, giving support to the hypothesis of habitat conditions driving the evolution of taxa with no strict host specificity. [ABSTRACT FROM AUTHOR]

Imperata is a ubiquitous grass genus of the tribe Andropogoneae (Poaceae), distributed throughout the world. Previous systematic studies had established that the genus encompasses nine species although no phylogenetic molecular studies are available in which all the taxa have been included. The American continent has the largest number of species, encouraging research into how these taxa have evolved. Here we present a phylogenetic analysis based on three plastids (ndhF, trnL-F, and atpB-rbcL) and one nuclear (ITS) marker that cover the most extensive geographic distribution of the genus. We use this phylogeny to test the monophyly of Imperata within tribe Andropogoneae, analyze the infrageneric relationships of the genus, and estimate lineage divergence time. Additionally, ecological niche models (ENM) of the American lineages are presented to recognize the abiotic factors that constraint their potential geographic distribution and allow an understanding of the ecological drivers for species diversification. Our results yield a fully supported tree where monophyly is confirmed for the genus and exposes the existence of two clades, one encompassing five American lineages and the other encompassing those of the rest of the world. In parallel, molecular dating, ENM, and ecological speciation tests suggest that American lineages underwent speciation during the Quaternary associated with conservatism and niche divergence. Our results contribute to both the taxonomic and to the evolutionary knowledge of grasses, and also to the understanding of the biological diversity in the Neotropics. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Ecological niche models (ENMs) have classically operated under the simplifying assumptions that there are no barriers to gene flow, species are genetically homogeneous (i.e., no population‐specific local adaptation), and all individuals share the same niche. Yet, these assumptions are violated for most broadly distributed species. Here, we incorporate genetic data from the widespread riparian tree species narrowleaf cottonwood (Populus angustifolia) to examine whether including intraspecific genetic variation can alter model performance and predictions of climate change impacts. We found that (1) P. angustifolia is differentiated into six genetic groups across its range from México to Canada and (2) different populations occupy distinct climate niches representing unique ecotypes. Comparing model discriminatory power, (3) all genetically informed ecological niche models (gENMs) outperformed the standard species‐level ENM (3–14% increase in AUC; 1–23% increase in pROC). Furthermore, (4) gENMs predicted large differences among ecotypes in both the direction and magnitude of responses to climate change and (5) revealed evidence of niche divergence, particularly for the Eastern Rocky Mountain ecotype. (6) Models also predicted progressively increasing fragmentation and decreasing overlap between ecotypes. Contact zones are often hotspots of diversity that are critical for supporting species' capacity to respond to present and future climate change, thus predicted reductions in connectivity among ecotypes is of conservation concern. We further examined the generality of our findings by comparing our model developed for a higher elevation Rocky Mountain species with a related desert riparian cottonwood, P. fremontii. Together our results suggest that incorporating intraspecific genetic information can improve model performance by addressing this important source of variance. gENMs bring an evolutionary perspective to niche modeling and provide a truly "adaptive management" approach to support conservation genetic management of species facing global change. [ABSTRACT FROM AUTHOR]

Limulus polyphemus is the sole extant representative of horseshoe crabs distributed along the Atlantic coast, and is threatened by human activities. Conservation priority to safeguard its habitat usually treats L. polyphemus as a whole, without consideration of different intraspecific ecological requirements. We seek to identify intraspecific ecological niche divergence or conservatism in L. polyphemus. In this study, ocean and coastal environmental conditions occupied by the six distinct metapopulations of L. polyphemus were collected, and compared using correlative approaches, niche overlaps among these six metapopulations were compared with geographical and genetic distances, the realized niche divergence/conservatism among these six metapopulations were tested, and ecological niche models were fitted for the six metapopulations separately and for L. polyphemus as a whole using state-of-the-art techniques. We found that mean sea surface temperature, tidal regime, chlorophyll a concentration, distance to shore and depth of seafloor were limiting factors in the geographic distribution of L. polyphemus. In addition to the former hypothesis that tidal amplitude and type account for the absence of L. polyphemus in the western Gulf of Mexico, our niche model predictions suggest that the narrow and high-depth seafloor in the western Gulf of Mexico also explain the absence. We found that realized niche overlaps among six metapopulations were not correlated with their geographic and genetic distances; rather the six metapopulations each occupied a unique combination of habitat conditions, showing different responses to environmental factors, although these divergences might be due a background effect. Results here showed that the distribution of one metapopulation of L. polyphemus cannot be inferred from changes in distribution of another, highlighting the inadequacy of one-size-fits-all conservation actions. We recommend that conservation priority assignment by IUCN and Natureserve for L. polyphemus would better consider the six metapopulations separately rather than L. polyphemus as a whole, which will deliver more useful information on guiding regional conservation efforts.

Abstract: Aim: Understanding the roles of allopatric fragmentation and niche divergence in intraspecific lineage diversification is central to our comprehension of how new species arise and evolve. Here we integrate an extensive multilocus dataset with species distribution models to address these topics in genetically differentiated population lineages of the common midwife toad (Alytes obstetricans). Location: Iberian Peninsula, Western Europe. Methods: We genotyped 965 individuals from 142 localities at 12 microsatellite loci to finely delineate the ranges of population lineages in A. obstetricans. We then built ecological niche‐based models for each lineage and tested for niche overlap, equivalency and similarity based on PCA‐env analyses. We also investigated the relationship between genetic and environmental distances across lineages. Results: We recovered seven differentiated genetic clusters, with mostly different (sometimes nonoverlapping) niches. However, niches are not more divergent than expected given the largely allopatric ranges of population lineages. We found no significant isolation by environment within lineages, with genetic distances mostly explained by geographical distances. Main conclusions: Allopatric fragmentation in A. obstetricans resulted in (sometimes highly) different niches in intraspecific population lineages. Within lineages, isolation by distance is the major driver of patterns of genetic variation. Our study highlights the importance of incorporating intraspecific genetic structure into species distribution models to explore spatial patterns of genetic diversity in terms of their underlying processes. [ABSTRACT FROM AUTHOR]

Abstract: Climate may play important roles in speciation, such as causing the range fragmentation that underlies allopatric speciation (through niche conservatism) or driving divergence of parapatric populations along climatic gradients (through niche divergence). Here, we developed new methods to test the frequency of climate niche conservatism and divergence in speciation, and applied it to species pairs of squamate reptiles (lizards and snakes). We used a large‐scale phylogeny to identify 242 sister species pairs for analysis. From these, we selected all terrestrial allopatric pairs with sufficient occurrence records (n = 49 pairs) and inferred whether each originated via climatic niche conservatism or climatic niche divergence. Among the 242 pairs, allopatric pairs were most common (41.3%), rather than parapatric (19.4%), partially sympatric (17.7%), or fully sympatric species pairs (21.5%). Among the 49 selected allopatric pairs, most appeared to have originated via climatic niche divergence (61–76%, depending on the details of the methods). Surprisingly, we found greater climatic niche divergence between allopatric sister species than between parapatric pairs, even after correcting for geographic distance. We also found that niche divergence did not increase with time, further implicating niche divergence in driving lineage splitting. Overall, our results suggest that climatic niche divergence may often play an important role in allopatric speciation, and the methodology developed here can be used to address the generality of these findings in other organisms. [ABSTRACT FROM AUTHOR]

Aim A fundamental problem in evolutionary biology has been understanding the role of environmental factors in the process of genetic diversification. Our main goal was to define the ecological niches of two Boa imperator lineages, in order to assess if environmental drivers could be associated with the divergence and genetic variation between them. We quantified the environmental niches at two evolutionary and geographical scales: regional-historical (lineages) and local-ecological (individuals within lineages). Location Neotropical region of Mexico and mainland Central America. Methods We performed ecological niche modelling ( ENM) methods by defining the accessibility area per B. imperator lineage, based on their geographic ranges, to analyse ecological and geographical distributions. We applied statistics of niche overlap, interpredictability, equivalency and similarity. We tested the niche-centrality hypothesis within lineages by evaluating the relationship between genetic metrics and the distance to ecological and geographical centroids. Results Temperature seasonality, precipitation and elevation were the most informative environmental variables ( GARP and MaxEnt). Ecological interprediction and niche similarity and equivalency tests revealed a dynamic process of niche evolution, where the niches of the two lineages are not identical but still showed a signature of niche conservatism. Correlation analyses between genetic variability and structure showed negative correlations with distance to ecological and geographical centroids at the local level. Main conclusions Our results support the role of environmental variables as significant and highly accurate predictors of lineage distribution and divergence, in agreement with the boa's evolutionary history. The niches of the two lineages are not identical, sharing environmental niche space but not all ecological variables. A historically more recent signal of genetic structure within lineages was evident, where the quality of the ecological niche further influences genetic distribution patterns within populations. Our results illustrate how ENM may validate evolutionary patterns from a biogeographical and phylogeographical framework. [ABSTRACT FROM AUTHOR]

The environmental variables that define a species ecological niche should be associated with the evolutionary patterns present in the adaptations that resulted from living in these conditions. Thus, when comparing across species, we can expect to find an association between phylogenetically independent phenotypic characters and ecological niche evolution. Few studies have evaluated how organismal phenotypes might mirror patterns of niche evolution if these phenotypes reflect adaptations. Doing so could contribute on the understanding of the origin and maintenance of phenotypic diversity observed in nature. Here, we show the pattern of niche evolution of the pinyon pine lineage ( Pinus subsection Cembroides); then, we suggest morphological adaptations possibly related to niche divergence, and finally, we test for correlation between ecological niche and morphology. We demonstrate that niche divergence is the general pattern within the clade and that it is positively correlated with adaptation. [ABSTRACT FROM AUTHOR]

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 environments, 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 environmental niches through two different approaches: ENMtools and multivariate methods. Important Findings MaxEnt 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 differentiation along altitudinal gradients and along a gradient of climatic conditions determined by the summer precipitation and temperatures. However, climatic conditions related to winter temperature 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. [ABSTRACT FROM AUTHOR]

Aim Diversification rates are critically important for understanding patterns of species richness, both among clades and among regions. However, the ecological correlates of variation in diversification rates remain poorly explored. Here, we test several hypotheses relating diversification rate and niche width across amphibian families (frogs and salamanders). Location Global. Methods We characterized climatic niches for 5784 amphibian species using databases for species distributions and climate. We estimated the niche width of each family using the range of values for climatic variables across all sampled species, and using the mean of species niche widths. We estimated diversification rates for families given their total number of described species and a time-calibrated phylogeny. We estimated relationships between variables using phylogenetic comparative methods. Results We found a significant positive relationship between family niche width and diversification rate, but a weak relationship between mean species niche width and diversification rate, despite both niche width variables being correlated. In fact, the deviation from this relationship (i.e. residuals of family niche width versus mean species niche width) was the best predictor of diversification rate. The observed relationship between niche width and diversification was independent of clade range size and niche position (e.g. whether clades occurred in tropical or temperate climates) and significantly different from null patterns derived from random sampling effects. Main conclusions Our results identify climatic niche width, and especially the relationship between family and species-level niche widths, as a major correlate of diversification rates among amphibian families. These results suggest that climatic niche divergence among species within clades can be important in explaining large-scale diversity patterns, possibly even more so than a clade's geographic area or whether it is primarily temperate or tropical. [ABSTRACT FROM AUTHOR]

Genetic diversity analyses, coupled with ecological niche modelling ( ENM) of species with a restricted distribution, may provide valuable information for understanding diversification patterns in endangered areas. We analyzed the genetic diversity of Recordia reitzii, a tree restricted to the threatened and highly fragmented Brazilian Atlantic forest, using three intergenic cpDNA spacers and ten microsatellite ( SSR) loci. To assess the historical processes that may have influenced the distribution of extant R. reitzii populations, the current potential distributions of R. reitzii and Recordia boliviana, a closely related species, were modelled and projected onto the Last Glacial Maximum ( LGM) and Last Interglacial ( LIG) periods. Niche divergence was quantified between these two. The cpDNA and SSR data showed a north-south pattern of the diversity distribution and structured populations, suggesting that gene flow is probably limited. According to our data, R. reitzii exhibits low genetic diversity, which may be a result of a founder or distribution-reduction effect, narrow distribution or small population size. The ecological niche models showed a wider palaeodistribution during the LIG and a retraction during the LGM for both species. Tests of niche divergence and conservatism indicated that bioclimatic factors might have influenced the diversification of these Recordia species. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 176, 332-348. [ABSTRACT FROM AUTHOR]

The Woodland Salamander genus Plethodon Tschudi, 1838, consists of terrestrial lungless salamanders, has been cited as an exemplar of a lineage characterized by niche conservatism. This conclusion has contributed to broader hypotheses dealing with the role of niche conservatism in speciation and the maintenance of species diversity. We re-evaluated these salamanders using newly published techniques designed to detect niche conservatism versus niche divergence using computer-based niche modeling and spatial analysis within a phylogenetic framework. We specifically studied parapatric neighbors in the species complex of Plethodon glutinosus (Green, 1818) to determine if there is evidence of a role for niche divergence at speciation or if niche conservatism characterizes the complex as has been reported for the larger genus. We found that new statistical approaches yield different results from earlier work, suggesting that niche divergence has been a much more important player in the speciation process than has heretofore been understood. Although different parts of the overall Plethodon phylogeny may be characterized by different rates of niche evolution, the rapidly burgeoning area of research centered on niche conservatism appears to be in a state of flux with regards to methods that give consistently repeatable results. [ABSTRACT FROM AUTHOR]

Speciation often has a strong geographical and environmental component, but the ecological factors that potentially underlie allopatric and parapatric speciation remain understudied. Two ecological mechanisms by which speciation may occur on geographic scales are allopatric speciation through niche conservatism and parapatric or allopatric speciation through niche divergence. A previous study on salamanders found a strong latitudinal pattern in the prevalence of these mechanisms, with niche conservatism dominating in temperate regions and niche divergence dominating in the tropics, and related this pattern to Janzen's hypothesis of greater climatic zonation between different elevations in the tropics. Here, we test for latitudinal patterns in speciation in a related but more diverse group of amphibians, the anurans. Using data from up to 79 sister-species pairs, we test for latitudinal variation in elevational and climatic overlap between sister species, and evaluate the frequency of speciation via niche conservatism versus niche divergence in relation to latitude. In contrast to salamanders, we find no tendency for greater niche divergence in the tropics or for greater niche conservatism in temperate regions. Although our results support the idea of greater climatic zonation in tropical regions, they show that this climatic pattern does not lead to straightforward relationships between speciation, latitude, and niche evolution. [ABSTRACT FROM AUTHOR]

• The two L. boscai lineages differed in their predicted potential distribution. • Intraspecific differences were independent of the distribution model algorithm used. • Lineages have a limited niche overlap and occur in different environmental niches. • Intraspecific variation improved lineage based-distribution models predictivity. Species distribution models (SDMs) treat species as a single unit, neglecting intraspecific variation. Few studies address the impact of intraspecific variation on SDM performance, and none of them account for the well-known inter-algorithm variability in prediction performance. The endemic Iberian amphibian Lissotriton boscai comprises two geographically highly structured phylogenetic lineages, which allowed us to explore how intraspecific variation affects the overall performance of SDMs and the predicted ecological niche. We built species and lineage distribution models using three different presence‐only algorithms. We also tested for niche overlap, niche equivalency and niche similarity, using an ordination technique. We found differences in the predicted potential distribution of the two lineages and the underlying environmental factors. Moreover, intraspecific differences in model predictive capacity existed irrespective of which algorithm was used to build the distribution models. This was coupled with lineages showing a low degree of niche overlap and occurring in relatively different environmental niches spaces. The intraspecific variation observed in L. boscai led to an improved intraspecific predictivity of the lineage level based-distribution models. There was partial spatial agreement between the niche overlap and independently reported secondary contact zones. Thus SDMs built only at the species level may be too naive to predict impacts of global change on species distributions. [ABSTRACT FROM AUTHOR]