Molecular Phylogeny Reveals High Diversity,Geographic Structure and Limited Ranges in Neotenic Net-Winged Beetles Platerodrilus (Coleoptera: Lycidae)

The neotenic Platerodrilus net-winged beetles have strongly modified development where females do not pupate and retain larval morphology when sexually mature. As a result, dispersal propensity of females is extremely low and the lineage can be used for reconstruction of ancient dispersal and vicariance patterns and identification of centres of diversity. We identified three deep lineages in Platerodrilus occurring predominantly in (1) Borneo and the Philippines, (2) continental Asia, and (3) Sumatra, the Malay Peninsula and Java. We document limited ranges of all species of Platerodrilus and complete species level turnover between the Sunda Islands and even between individual mountain regions in Sumatra. Few dispersal events were recovered among the major geographical regions despite long evolutionary history of occurrence; all of them were dated at the early phase of Platerodrilus diversification up to the end of Miocene and no exchange of island faunas was identified during the Pliocene and Pleistocene despite the frequently exposed Sunda Shelf as sea levels fluctuated with each glacial cycle. We observed high diversity in the regions with persisting humid tropical forests during cool periods. The origins of multiple species were inferred in Sumatra soon after the island emerged and the mountain range uplifted 15 million years ago with the speciation rate lower since then. We suppose that the extremely low dispersal propensity makes Platerodrilus a valuable indicator of uninterrupted persistence of rainforests over a long time span. Additionally, if the diversity of these neotenic lineages is to be protected, a high dense system of protected areas would be necessary.     

Multiple ancient origins of neoteny in Lycidae(Coleoptera): consequences for ecology and macroevolution

Neoteny, the maintenance of larval features in sexually mature adults, is a radical way of generating evolutionary novelty through shifts in relative timing of developmental programmes. While controlled by the environment in facultative neotenics, retention of larval features is obligatory in many species of Lycidae (net-winged beetles). They are studied here as an example of how developmental shifts and ecology interact to produce macroevolutionary impacts. We conducted a phylogenetic analysis of Lycidae based on DNA sequences from nuclear (18S and 28S rRNA) and mitochondrial (rrnL, cox1, cob and nad5) genes from a representative set of lineages (73 species), including 17 neotenic taxa. Major changes of basal relationships compared with those implied in the current classification generally supported three independent origins of neotenics in Lycidae. The southeast Asian Lyropaeinae and Ateliinae were in basal positions indicating evolutionary antiquity, also confirmed by molecular clock estimates, unlike the neotropical leptolycines nested within Calopterini and presumably much younger. neotenics exhibit typical K-selected traits including slow development, large body size, high investment in offspring and low dispersal. This correlated with low species richness and restricted ranges of neotenic lineages compared with their sisters. Yet, these factors did not impede the evolutionary persistence of affected lineages, even without reversals to fully metamorphosed forms, contradicting earlier suggestions of recent evolution from dispersive non-neotenics.     

Contrasting patterns of diversification in a bird family (Aves: Gruiformes: Rallidae) are revealed by analysis of geospatial distribution of species and phylogenetic diversity

Geospatial patterns in the distribution of regional biodiversity reflect the composite processes that underpin evolution: speciation, dispersal and extinction. The spatial distribution and phylogeny of a globally widespread and species rich bird family (Rallidae) were used to help assess the role of large‐scale biogeographical processes in diversity and diversification. Here, we examine how different geostatistical diversity metrics enhance our understanding of species distribution by linking occurrence records of rail species to corresponding species level phylogeny. Tropical regions and temperate zones contained a large proportion of rail species richness and phylogenetic diversity whilst small islands in Australian, Oceanian and Oriental regions held the highest weighted and phylogenetic endemism. Our results suggest that habitat connectivity and dispersal were important ecological features in rail evolution and distribution. Spatial isolation was a significant driver of diversification where islands in Oceania were centres of neo‐endemism with recent multiple and independent speciation events and could be considered as nurseries of biodiversity. Palaeo‐endemism was mostly associated with older stable regions, so despite extensive long distance range shifting these areas retain their own ancient and distinct character. Madagascar was the major area of palaeo‐endemism associated with the oldest rail lineages and could be considered a museum of rail diversity. This implies a mixture of processes determine the current distribution and diversity of rail clades with some areas dominated by recent ‘in situ’ speciation while others harbour old diversity with ecological traits that have stood the test of time.     

Speciation below ground: Tempo and mode of diversification in a radiation of endogean ground beetles

Dispersal is a critical factor determining the spatial scale of speciation, which is constrained by the ecological characteristics and distribution of a species’ habitat and the intrinsic traits of species. Endogean taxa are strongly affected by the unique qualities of the below‐ground environment and its effect on dispersal, and contrasting reports indicate either high dispersal capabilities favoured by small body size and mediated by passive mechanisms, or low dispersal due to restricted movement and confinement inside the soil. We studied a species‐rich endogean ground beetle lineage, Typhlocharina, including three genera and more than 60 species, as a model for the evolutionary biology of dispersal and speciation in the deep soil . A time‐calibrated molecular phylogeny generated from >400 individuals was used to delimit candidate species, to study the accumulation of lineages through space and time by species–area–age relationships and to determine the geographical structure of the diversification using the relationship between phylogenetic and geographic distances across the phylogeny. Our results indicated a small spatial scale of speciation in Typhlocharina and low dispersal capacity combined with sporadic long distance, presumably passive dispersal events that fuelled the speciation process. Analysis of lineage growth within Typhlocharina revealed a richness plateau correlated with the range of distribution of lineages, suggesting a long‐term species richness equilibrium mediated by density dependence through limits of habitat availability. The interplay of area‐ and age‐dependent processes ruling the lineage diversification in Typhlocharina may serve as a general model for the evolution of high species diversity in endogean mesofauna.     

Dispersal has inhibited avian diversification in Australasian archipelagoes

Different models of speciation predict contrasting patterns in the relationship between the dispersal ability of lineages and their diversification rates. This relationship is expected to be negative in isolation-limited models and positive in founder-event models. In addition, the combination of negative and positive effects of dispersal on speciation can result in higher diversification rates at intermediate levels of dispersal ability. Using molecular phylogenies to estimate diversification rates, and wing morphology to estimate dispersal ability, we analysed the influence of dispersal on diversification in the avifauna of Australasian archipelagoes. Contrary to expectations given the fragmented nature of island systems, the relationship between dispersal ability and diversification rate was monotonically negative. While multiple mechanisms could generate this pattern, they all share a phase of range expansion that is decoupled from speciation.     

Does the colonization of new biogeographic regions influence the diversification and accumulation of clade richness among the Corvides (Aves: Passeriformes)?

Regional variation in clade richness can be vast, reflecting differences in the dynamics of historical dispersal and diversification among lineages. Although it has been proposed that dispersal into new biogeographic regions may facilitate diversification, to date there has been limited assessment of the importance of this process in the generation, and maintenance, of broad‐scale biodiversity gradients. To address this issue, we analytically derive biogeographic regions for a global radiation of passerine birds (the Corvides, c. 790 species) that are highly variable in the geographic and taxonomic distribution of species. Subsequently, we determine rates of historical dispersal between regions, the dynamics of diversification following regional colonization, and spatial variation in the distribution of species that differ in their rates of lineage diversification. The results of these analyses reveal spatiotemporal differences in the build‐up of lineages across regions. The number of regions occupied and the rate of transition between regions both predict family richness well, indicating that the accumulation of high clade richness is associated with repeated expansion into new geographic areas. However, only the largest family (the Corvidae) had significantly heightened rates of both speciation and regional transition, implying that repeated regional colonization is not a general mechanism promoting lineage diversification among the Corvides.     

The shape and temporal dynamics of phylogenetic trees arising from geographic speciation

Phylogenetic trees often depart from the expectations of stochastic models, exhibiting imbalance in diversification among lineages and slowdowns in the rate of lineage accumulation through time. Such departures have led to a widespread perception that ecological differences among species or adaptation and subsequent niche filling are required to explain patterns of diversification. However, a key element missing from models of diversification is the geographical context of speciation and extinction. In this study, we develop a spatially explicit model of geographic range evolution and cladogenesis, where speciation arises via vicariance or peripatry, and explore the effects of these processes on patterns of diversification. We compare the results with those observed in 41 reconstructed avian trees. Our model shows that nonconstant rates of speciation and extinction are emergent properties of the apportioning of geographic ranges that accompanies speciation. The dynamics of diversification exhibit wide variation, depending on the mode of speciation, tendency for range expansion, and rate of range evolution. By varying these parameters, the model is able to capture many, but not all, of the features exhibited by birth-death trees and extant bird clades. Under scenarios with relatively stable geographic ranges, strong slowdowns in diversification rates are produced, with faster rates of range dynamics leading to constant or accelerating rates of apparent diversification. A peripatric model of speciation with stable ranges also generates highly unbalanced trees typical of bird phylogenies but fails to produce realistic range size distributions among the extant species. Results most similar to those of a birth-death process are reached under a peripatric speciation scenario with highly volatile range dynamics. Taken together, our results demonstrate that considering the geographical context of speciation and extinction provides a more conservative null model of diversification and offers a very different perspective on the phylogenetic patterns expected in the absence of ecology.     

Mountainous genus Anterastes (Orthoptera,Tettigoniidae): autochthonous survival across several glacial ages via vertical range shifts

Although the high‐latitude range margins in Europe and North America are intensively studied, attention is gradually turned towards the taxa/populations inhabiting glacial refugia. Here, we evaluate the genealogical history of the cold‐adapted Anatolio‐Balkan genus Anterastes especially to test the possible effects of intrarefugial vertical range shifts during climatic oscillations of the Quaternary. Using concatenated data from sequences of COI+16S and ITS1–5.8S–ITS2, intrageneric relationships and the time of speciation events were estimated. Thirteen different demographic analyses were performed using a data set produced from sequences of 16S. Different phylogenetic analyses recovered similar lineages with high resolution. The molecular chronogram estimated speciation events in a period ranging from 5.60 to 1.22 Myr. Demographic analyses applied to 13 populations and five lineages suggested constant population size. Genetic diversity is significantly reduced in a few populations, while not in others. Fixation indices suggested extremely diverged populations. In the light of these data, the following main conclusions were raised: (i) although glacial refugia are the biodiversity hotspots, species level radiation of the cold‐adapted lineages is mainly prior to the Mid‐Pleistocene transition; (ii) heterogeneous topography provides refugial habitats and allows populations to survive through vertical range shifts during climatic fluctuations; (iii) prolonged isolation of refugial populations do not always result in reduced intrapopulation diversity, but in high level of genetic differentiation; (iv) the cold‐adapted lineages with low dispersal ability might have not colonised the area out of Anatolian refugium during interglacial periods; and (v) populations of invertebrates may have restricted ranges, but this does not mean that they have small effective population size.     

Influence of the geography of speciation on current patterns of coral reef fish biodiversity across the Indo‐Pacific

The role of speciation processes in shaping current biodiversity patterns represents a major scientific question for ecologists and biogeographers. Hence, numerous methods have been developed to determine the geography of speciation based on co‐occurrence between sister‐species. Most of these methods rely on the correlation between divergence time and several metrics based on the geographic ranges of sister‐taxa (i.e. overlap, asymmetry). The relationship between divergence time and these metrics has scarcely been examined in a spatial context beyond regression curves. Mapping this relationship across spatial grids, however, may unravel how speciation processes have shaped current biodiversity patterns through space and time. This can be particularly relevant for coral reef fishes of the Indo‐Pacific since the origin of the exceptional concentration of biodiversity in the Indo‐Australian Archipelago (IAA) has been actively debated, with several alternative hypotheses involving species diversification and dispersal. We reconstructed the phylogenetic relationships between three species‐rich families of coral reef fish (Chaetodontidae, Labridae, Pomacentridae) and calculated co‐occurrence metrics between closely related lineages of those families. We demonstrated that repeated biogeographic processes can be identified in present‐day species distribution by projecting co‐occurrence metrics between related lineages in a geographical context. Our study also evidence that sister‐species do not co‐occur randomly across the Indo‐Pacific, but tend to overlap their range within the IAA. We identified the imprint of two important biogeographic processes that caused this pattern in 48% of the sister‐taxa considered: speciation events within the IAA and repeated divergence between the Indian and Pacific Ocean, with subsequent secondary contact in the IAA.     

High dispersal ability inhibits speciation in a continental radiation of passerine birds

Dispersal can stimulate speciation by facilitating geographical expansion across barriers or inhibit speciation by maintaining gene flow among populations. Therefore, the relationship between dispersal ability and speciation rates can be positive or negative. Furthermore, an 'intermediate dispersal' model that combines positive and negative effects predicts a unimodal relationship between dispersal and diversification. Because both dispersal ability and speciation rates are difficult to quantify, empirical evidence for the relationship between dispersal and diversification remains scarce. Using a surrogate for flight performance and a species-level DNA-based phylogeny of a large South American bird radiation (the Furnariidae), we found that lineages with higher dispersal ability experienced lower speciation rates. We propose that the degree of fragmentation or permeability of the geographical setting together with the intermediate dispersal model are crucial in reconciling previous, often contradictory findings regarding the relationship between dispersal and diversification.     

Deep-sea squat lobster biogeography (Munidopsidae: Leiogalathea) unveils Tethyan vicariance and evolutionary patterns shared by shallow-water relatives

The ecology, abundance and diversity of galatheoid squat lobsters make them an ideal group to study deep-sea diversification processes. Here, we reconstructed the evolutionary and biogeographic history of Leiogalathea, a genus of circum-tropical deep-sea squat lobsters, in order to compare patterns and processes that have affected shallow-water and deep-sea squat lobster species. We first built a multilocus phylogeny and a calibrated species tree with a relaxed clock using StarBEAST2 to reconstruct evolutionary relationships and divergence times among Leiogalathea species. We used BioGeoBEARS and a DEC model, implemented in RevBayes, to reconstruct ancestral distribution ranges and the biogeographic history of the genus. Our results showed that Leiogalathea is monophyletic and comprises four main lineages; morphological homogeneity is common within and between clades, except in one; the reconstructed ancestral range of the genus is in the Atlantic and Indian oceans (Tethys). They also revealed the divergence of the Atlantic species around 25 million years ago (Ma), intense cladogenesis 15–25 Ma and low levels of speciation over the last 5 million years (Myr). The four Leiogalathea lineages showed similar patterns of speciation: allopatric speciation followed by range expansion and subsequent stasis. Leiogalathea started diversifying during the Oligocene, likely in the Tethyan. The Atlantic lineage then split from its Indo-Pacific sister group due to vicariance driven by closure of the Tethys Seaway. The Atlantic lineage is less speciose compared with the Indo-Pacific lineages, with the Tropical Southwestern Pacific being the current centre of diversity. Leiogalathea diversification coincided with cladogenetic peaks in shallow-water genera, indicating that historical biogeographic events similarly shaped the diversification and distribution of both deep-sea and shallow-water squat lobsters.     

Demographic history,geographical distribution and reproductive isolation of distinct lineages of blue rockfish (Sebastes mystinus), a marine fish with a high dispersal potential

Understanding the barriers to genetic exchange in taxonomic groups that have a high dispersal potential will provide critical information on speciation in general. Blue rockfish (Sebastes mystinus) are good taxa to examine speciation because they are nonmigratory inhabitants of shallow rocky reef habitats along the eastern North Pacific with a pelagic larval stage lasting 3–5 months. The goal of this study was to analyse the evolutionary history and distribution patterns of different lineages within S. mystinus described previously and use this information to understand the speciation process in this group of high dispersal fish. The molecular data derived from specimens sampled over approximately 1650 km of the S. mystinus range revealed a northerly and southerly distribution for the two lineages. Almost equal frequencies of both lineages occurred at centrally located sample locations, with evidence of reproductive isolation between the lineages. A demographic analysis showed that the two lineages diverged and experienced sudden expansion prior to the last glacial maximum, which affected the observed pattern of genetic structure. The spatial distribution, demographic history and degree of genetic distinctiveness found from the genetic analysis, despite the high potential for dispersal in S. mystinus, suggest both lineages diverged in allopatry.     

Ants Sow the Seeds of Global Diversification in Flowering Plants

Background

The extraordinary diversification of angiosperm plants in the Cretaceous and Tertiary periods has produced an estimated 250,000–300,000 living angiosperm species and has fundamentally altered terrestrial ecosystems. Interactions with animals as pollinators or seed dispersers have long been suspected as drivers of angiosperm diversification, yet empirical examples remain sparse or inconclusive. Seed dispersal by ants (myrmecochory) may drive diversification as it can reduce extinction by providing selective advantages to plants and can increase speciation by enhancing geographical isolation by extremely limited dispersal distances.

Methodology/Principal Findings

Using the most comprehensive sister-group comparison to date, we tested the hypothesis that myrmecochory leads to higher diversification rates in angiosperm plants. As predicted, diversification rates were substantially higher in ant-dispersed plants than in their non-myrmecochorous relatives. Data from 101 angiosperm lineages in 241 genera from all continents except Antarctica revealed that ant-dispersed lineages contained on average more than twice as many species as did their non-myrmecochorous sister groups. Contrasts in species diversity between sister groups demonstrated that diversification rates did not depend on seed dispersal mode in the sister group and were higher in myrmecochorous lineages in most biogeographic regions.

Conclusions/Significance

Myrmecochory, which has evolved independently at least 100 times in angiosperms and is estimated to be present in at least 77 families and 11 000 species, is a key evolutionary innovation and a globally important driver of plant diversity. Myrmecochory provides the best example to date for a consistent effect of any mutualism on large-scale diversification.     

Reconstruction of the spatio-temporal diversification and ecological niche evolution of Helianthemum (Cistaceae) in the Canary Islands using genotyping-by-sequencing data

Background and AimsSeveral biogeographical models have been proposed to explain the colonization and diversification patterns of Macaronesian lineages. In this study, we calculated the diversification rates and explored what model best explains the current distribution of the 15 species endemic to the Canary Islands belonging to Helianthemum sect. Helianthemum (Cistaceae).MethodsWe performed robust phylogenetic reconstructions based on genotyping-by-sequencing data and analysed the timing, biogeographical history and ecological niche conservatism of this endemic Canarian clade.Key ResultsOur phylogenetic analyses provided strong support for the monophyly of this clade, and retrieved five lineages not currently restricted to a single island. The pristine colonization event took place in the Pleistocene (~1.82 Ma) via dispersal to Tenerife by a Mediterranean ancestor.ConclusionsThe rapid and abundant diversification (0.75–1.85 species per million years) undergone by this Canarian clade seems the result of complex inter-island dispersal events followed by allopatric speciation driven mostly by niche conservatism, i.e. inter-island dispersal towards niches featuring similar environmental conditions. Nevertheless, significant instances of ecological niche shifts have also been observed in some lineages, making an important contribution to the overall diversification history of this clade.     

A dynamic global equilibrium in carnivoran diversification over 20 million years

The ecological and evolutionary processes leading to present-day biological diversity can be inferred by reconstructing the phylogeny of living organisms, and then modelling potential processes that could have produced this genealogy. A more direct approach is to estimate past processes from the fossil record. The Carnivora (Mammalia) has both substantial extant species richness and a rich fossil record. We compiled species-level data for over 10 000 fossil occurrences of nearly 1400 carnivoran species. Using this compilation, we estimated extinction, speciation and net diversification for carnivorans through the Neogene (22–2 Ma), while simultaneously modelling sampling probability. Our analyses show that caniforms (dogs, bears and relatives) have higher speciation and extinction rates than feliforms (cats, hyenas and relatives), but lower rates of net diversification. We also find that despite continual species turnover, net carnivoran diversification through the Neogene is surprisingly stable, suggesting a saturated adaptive zone, despite restructuring of the physical environment. This result is strikingly different from analyses of carnivoran diversification estimated from extant species alone. Two intervals show elevated diversification rates (13–12 Ma and 4–3 Ma), although the precise causal factors behind the two peaks in carnivoran diversification remain open questions.     

Pleistocene extinctions as drivers of biogeographical patterns on the easternmost Canary Islands

Subtropical islands are often viewed as refuges where Quaternary climatic shifts driving global episodes of extinction were buffered. Island biodiversity, however, may have been impacted by climatic fluctuations at local scales, particularly in spatially heterogeneous island systems. In this study, we generated a conceptual framework for predicting the potential impact of Pleistocene extinctions on the biogeographical pattern of the Canarian spermatophyte flora, with a focus on the easternmost Canarian islands (ECI). Then, we performed an exhaustive bibliographic revision (270 studies) to examine whether taxonomic, phylogenetic and phylogeographical data support our predictions. Although molecular information is limited for many lineages, the available data suggest that the majority of extant ECI plant taxa may be the result of relatively recent (<1 Ma) dispersal from surrounding insular and mainland areas. Different lines of evidence are compatible with the idea of a Pleistocene period of frequent lineage extirpation on ECI. Extinction may thus have provided new ecological opportunities for recent (re)colonization, with some cases of recent establishment mediated by facilitation. Considering background extinction on ECI, we describe five general patterns of colonization for Canarian plant lineages. In addition to factors related to island ontogeny and long‐distance dispersal, we suggest that Pleistocene extinctions may have significantly contributed to extant biogeographical patterns in the Canarian archipelago, such as the biased distribution ranges of island plants and the low endemic richness on ECI. This new scenario provides testable hypotheses for future studies dealing with the phylogeography, taxonomy and conservation of terrestrial biodiversity on the Canarian islands, and possibly, on other near‐shore islands.     

Extensive Miocene speciation in and out of Indochina: The biogeographic history of Typhonium sensu stricto (Araceae) and its implication for the assembly of Indochina flora

The Asian paleotropical flora is characterized by abundance of endemic species, high biodiversity, and complex geological and climatic histories. However, the main driving mechanism underlying such high tropical biodiversity remains unclear. Hence, the present study aimed to investigate the biogeographic origin of the Asian paleotropical flora by tracking the speciation and diversification history of a typical tropical perennial, Typhonium sensu stricto (s.s.) (Araceae), using a time-calibrated whole-plastome phylogeny. In particular, we tested whether the Asian paleotropic region is a macroevolutionary source or sink. We observed that Typhonium s.s. originated in Indochina during the early–middle Miocene epoch, ca. 17.24 Ma (95% highest posterior density [HPD]: 12.83 ̶ 21.99 Ma). Most of the in situ diversification within the genus Typhonium s.s. has been underway since 14.73 Ma, with an accelerated lineage diversification at ca. 15−17 Ma, which may have been triggered by the intensification of the Asian monsoon system around the middle Miocene. Furthermore, the underground tuberous stem of Typhonium s.s. might have played an essential role in the adaptation to the seasonality caused by the monsoon in Indochina. Our results also suggested that peripatric speciation may be important in the diversification of T. trilobatum and T. roxburghii. This study provides a framework for studies in biogeography and evolution of the Asian paleotropical flora.     

The influence of group size on ovarian development in adult and neotenic reproductives of the termite Zootermopsis angusticollis (Hagen) (Hodotermitidae)

Termite imagines of Zootermopsis angusticollis (Hagen), while still in the colony as winged individuals, do not show ovary development, although vitellogenin is present in the blood at low levels. When removed from the colony, artificially dealated, and paired, vitellogenin levels rise: subsequently ovaries develop resulting in oviposition approximately 15–16 days after removal from the colony. Imagines removed from the colony, dealated and held together in a heterosexual group, however, show little or no ovary development after 25 days, although vitellogenin is present in the haemolymph in low levels. Newly developed neotenic reproductives, on the other hand, removed from the colonly 1–2 days after the neotenic moult, and isolated in heterosexual pairs for 60 days, had ovaries which did not become larger than 0.02 mm³, and no eggs were laid. This is in contrast to the normal ovary development of neotenic reproductives produced in groups of larvae, as described earlier. Vitellogenin levels in isolated pairs of neotenics were low until 25 days after isolation, while vitellogenin levels increased 7–9 days after the moult in female neotenics kept in a colony with larvae. The results of this study on ovarian development and vitellogenesis in neotenic and adult reproductives reflect the normal biology of the two reproductive types where the latter leave the colony to found new colonies, while neotenics become sexually mature within the colony in which they developed.     

Low mountain ranges: summit traps for montane freshwater species under climate change

Global climate change (GCC) is expected to lead to massive loss of global biodiversity in the alpine regions of mountain ranges. Studies on the potential effects of GCC on low mountain areas remain sparse, however, despite the high conservation value of these areas as biodiversity refugia. We chose a species distribution modeling approach to assess potential GCC impacts on the future distributions of montane freshwater invertebrates under two different greenhouse gas scenarios and three averaged general circulation models. For this, ensemble models consisting of six algorithms [generalized linear model (GLM), generalized boosted model (GBM), generalized additive model (GAM), classification tree analysis (CTA), artificial neural networks (ANN), and multivariate adaptive regression splines (MARS)] were applied to project areas of 23 cold-stenothermic aquatic insects from montane regions of Central Europe. We found an average loss of 70–80% of the potential distribution for the study species until 2080, depending on the underlying Intergovernmental Panel on Climate Change scenario. Species distribution ranges below 1000 m above sea level were found to decrease by up to ~96% according to the severest greenhouse gas emission scenario. While the Alps remain the single main refugium under the A2a greenhouse gas emission scenario, the more moderate climate scenario B2a shows fragmented potential persistence of montane insects in some low mountain ranges. The results show that montane freshwater assemblages in low mountain ranges are particularly threatened by ongoing GCC. As vertical dispersal is limited by elevational restriction, low mountain ranges may act as summit traps under GCC. We thus propose that GCC will lead to the extinction of several species and unique genetic lineages of postglacial relict species, resulting in a significant decline in Central European fauna.     

Ancient islands acted as refugia and pumps for conifer diversity

Island species are thought to be extinction‐prone because of small population sizes, restricted geographical distribution and limited dispersal ability. However, the topographical and environmental heterogeneity, geographical isolation and stability of islands over long timescales could create refugia for taxa whose source area is threatened by environmental changes. We address this possibility by inferring the evolution of the New Caledonia (NC) and New Zealand (NZ) conifer diversity, which represents over 10% of the world's diversity for this group. We estimate speciation and extinction rates in relation to the presence/absence on these islands, and dispersal rates between the islands and surrounding areas. We also test the Eocene submersion of NC and the Oligocene drowning of NZ by comparing the fit of biogeographical scenarios using ancestral area estimations. We find that extinction rates were significantly lower for island species, and dispersal “out of islands” was higher. A model including a diversification shift when NC emerged better explains the diversification dynamics. Biogeographical analyses corroborate that conifers experienced high continental extinctions, but survived on islands. NC and NZ have thus contributed to the world's conifer diversity as “island refugia”, by maintaining early‐diverging lineages from continents during environmental changes on continents. These ancient islands also acted as “species pumps”, providing species into adjacent areas. Our study highlights the important but neglected role of islands in promoting the evolution and conservation of biodiversity.