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Aim: To investigate the historical distribution of the Cerrado across Quaternary climatic fluctuations and to generate historical stability maps to test: (1) whether the 'historical climate' stability hypothesis explains squamate reptile richness in the Cerrado; and (2) the hypothesis of Pleistocene connections between savannas located north and south of Amazonia. Location: The Cerrado, a savanna biome and a global biodiversity hotspot distributed mainly in central Brazil. Methods: We generated occurrence datasets from 1000 presence points randomly selected from the entire distribution of the Cerrado, as determined by two spatial definitions. We modelled the potential Cerrado distribution by implementing a maximum-entropy machine-learning algorithm across four time projections: current, mid-Holocene (6 ka), Last Glacial Maximum (LGM, 21 ka) and Last Interglacial (LIG, 120 ka). We generated historical stability maps (refugiai areas) by overlapping presence/absence projections of all scenarios, and checked consistencies with qualitative comparisons with available fossil pollen records. We built a spatially explicit simultaneous autoregressive model to explore the relationship between current climate, climatic stability, and squamate species richness. Results: Models predicted the LGM and LIG as the periods of narrowest and widest Cerrado distributions, respectively, and were largely corroborated by palynological evidence. We found evidence for two savanna corridors (eastern coastal during the LIG, and Andean during the LGM) and predicted a large refugiai area in the north-eastern Cerrado (Serra Geral de Goiás refugium). Variables related to climatic stability predicted squamate richness better than present climatic variables did. Main conclusions: Our results indicate that Bolivian savannas should be included within the Cerrado range and that the Cerrado's biogeographical counterparts are not Chaco and Caatinga but rather the disjunct savannas of the Guyana shield plateaus. Climatic stability is a good predictor of Cerrado squamate richness, and our stability maps could be used in future studies to test diversity patterns and genetic signatures of different taxonomic groups and as a higher-order landscape biodiversity surrogate for conservation planning.

Aim: We studied which factors shape contemporary patterns of genetic structure, diversity and admixture in the canyon live oak (Quereus chrysolepis). Specifically, we tested two alternative hypotheses: (1) that areas with high habitat suitability and stability since the Last Glacial Maximum (LGM) sustain higher effective population sizes, resulting in increased levels of genetic diversity; and (2) that populations from areas with lower habitat stability show higher levels of genetic admixture due to their recurrent colonization by individuals originating from genetically differentiated populations. Furthermore, we analysed the relative importance of past and current habitat suitability and their additive effects on contemporary patterns of genetic structure. Location: California, USA. Methods: We sampled 160 individuals from 33 localities across the distribution range of the canyon live oak in California and then combined information from 13 nuclear microsatellite DNA markers and climate niche modelling to study patterns of genetic variation in this species. We used Bayesian clustering analyses to analyse geographical patterns of genetic structure and admixture, and circuit theory to generate isolation-by-resistance (IBR) distance matrices. Results: We found that the degree of genetic admixture was higher in localities with lower inferred population stability, but that genetic diversity was not associated with habitat suitability or stability. Landscape genetic analyses identified habitat stability as the primary driver of population genetic differentiation. Main conclusions: This study shows that habitat stability can be a major factor shaping genetic variation in wind-pollinated trees and supports the idea that stable regions contribute to genetic connectivity across different climatic periods. To our knowledge, this study is the first to report an association between patterns of genetic admixture and stability of local habitat.

Aim: Our goal was to test the hypothesis that ancient humans substantially contributed to shaping the current distribution of Brazil nut (Bertholletia excelsa), an Amazonian tree species that has been important for human livelihoods since pre-Columbian times. We scrutinized the putative association between Brazil nut and Amazonian Dark Earth soils (ADE) and geometric earthworks called geoglyphs, and examined the existence of continental patterns in human footprints on Brazil nut stands. Location: Amazon Basin. Methods: We carried out a spatially explicit meta-analysis of the variation of Brazil nut stand metrics across the Amazon Basin based on 87,617 density estimates and 488 average stand diameter assessments, and related these to previously published datasets and suitability maps of Brazil nut, ADE and geoglyphs. Results: We found consistently higher Brazil nut suitability scores, stand densities and average stand diameters in the vicinities of ADE than at larger distances, regardless of their position along a gradient from south-western to north-eastern Amazonia. For geoglyph sites such a pattern was only found for Brazil nut habitat suitability scores. The available data further revealed an accumulation of Brazil nut stands with increasing densities and average diameters from south-western to central and eastern Amazonia. Main conclusions: Our findings suggest that the chance of encountering Brazil nut stands bearing the marks of past human influences increases from south-western to central and eastern Amazonia. In south-western Amazonia, the regeneration of Brazil nut seems to have been controlled predominantly by natural processes, whereas in central and eastern Amazonia, anthropogenic disturbance has been more important since pre-Columbian times. However, it remains challenging to disentangle human influences on the distribution and abundance of Brazil nut from existing environmental gradients across the Amazon Basin. In general, the results of this meta-analysis bode well for the future coexistence of Brazil nut with different forms of contemporary human land use.

Aim: Species distribution modelling (SDM) has increasingly been used to predict palaeodistributions at regional and global scales in order to understand the response of vegetation to climate change and to estimate palaeodistributions for the testing of biogeographical hypotheses. However, there are many sources of uncertainty in SDM that may restrict the ability of models to hindcast palaeodistributions and provide a basis for hypothesis testing in molecular phylogenetics and phylogeographical studies. Location: Seasonally dry forests (SDFs) in South America. Methods: We addressed the problem of using palaeodistribution modelling for SDFs based on the projection of their current distribution into past environments (21 ka) using 11 methods for SDMs and five coupled atmosphere—ocean global circulation models (AOGCMs) for 16 species. Results: We observed considerable uncertainty in the hindcasts, with the most important effects for AOGCM (median 12.2%), species (median 15.6%) and their interaction (median 13.6%). The effects of AOGCMs were stronger in the Amazon region, whereas the species effect occurred primarily in the dry areas of central Brazil. The log-linear model detected significant effects of the three sources of variation and their interaction on the classification of each map in supporting alternative hypotheses. An expansion scenario combining the Pleistocene arc and Amazonian expansion, and Pennington's Amazonian expansion alone, were the most frequently supported palaeodistribution scenarios. Main conclusions: As a basis for evaluating a given hypothesis, hindcast distributions must be used in direct association with other evidence, such as molecular variation and the fossil record. We propose an alternative framework concerning hypothesis testing that couples SDM and phylogeographical work, in which palaeoclimatic distributions and other sources of information, such as the pollen fossil record and coalescence modelling, must be weighted equally.

AIM: Pelophylax frogs in East Asia provide an opportunity to explore the impact of glacial cycling on demographic and genetic dynamics, because it has been suggested that they experienced distribution shifts and subsequent mtDNA introgression from Pelophylax plancyi to Pelophylax nigromaculatus in association with climatic oscillations. However, their evolutionary history, including the pattern of introgression, is incompletely understood. We used phylogenetic analyses based on multiple markers to address their evolutionary history, and palaeodistribution modelling to test whether the predicted distribution can explain the pattern of introgression suggested by molecular phylogenetics. LOCATION: East Asia, including far‐eastern Russia, mainland China, the Japanese archipelago, the Korean Peninsula and Taiwan. METHODS: Ninety‐nine samples of the Pelophylax nigromaculatus species complex were collected from 75 localities throughout the distributional range of each species. Phylogenetic analyses were performed with the mitochondrial cytochrome b (cytb) gene and six nuclear genes using two European Pelophylax frogs as outgroups. Additionally, palaeodistributions of P. nigromaculatus and P. plancyi were predicted using bioclimatic variables. RESULTS: Differences were observed between the mitochondrial and nuclear DNA trees in the phylogenetic position of P. plancyi. Similar phylogenetic discordance was also observed within P. nigromaculatus. Distribution modelling suggested that a considerable distributional shift of P. nigromaculatus occurred in association with glacial cycling and that the distributional range of P. plancyi was relatively narrow during glacial periods. MAIN CONCLUSIONS: The analyses detected five historical mtDNA introgression events and determined their directions, none of which had been deduced in previous studies. In association with glacial cycling, the distributional ranges of P. nigromaculatus and P. plancyi appear to have shifted repeatedly, resulting in multiple complex introgressions. By combining phylogenetic analyses with palaeodistribution modelling, our results supported the hypothesis that the history of mtDNA introgression among Pelophylax frogs was shaped by glacial cycling.

This paper describes a new species of extinct whitefly in the genus Gregorites Drohojowska & Szwedo, 2024, from the family Aleyrodidae. This species has been identified based on an inclusion in Eocene Baltic amber. This represents the eighth documented species of the genus and contributes new data to our knowledge of the disparity and taxonomic diversity of whiteflies in Eocene Baltic amber. The discovery of a further Gregorites species, previously known only from succinite on the western coast of Jutland, raises questions about the amberiferous deposits, their geology and history, and on palaeodistributions of the whiteflies. These are briefly reviewed and discussed.

Statistical phylogeographic studies contribute to our understanding of the factors that influence population divergence and speciation, and that ultimately generate biogeographical patterns. The use of coalescent modelling for analyses of genetic data provides a framework for statistically testing alternative hypotheses about the timing and pattern of divergence. However, the extent to which such approaches contribute to our understanding of biogeography depends on how well the alternative hypotheses chosen capture relevant aspects of species histories. New modelling techniques, which explicitly incorporate spatio-geographic data external to the gene trees themselves, provide a means for generating realistic phylogeographic hypotheses, even for taxa without a detailed fossil record. Here we illustrate how two such techniques - species distribution modelling and its historical extension, palaeodistribution modelling - in conjunction with coalescent simulations can be used to generate and test alternative hypotheses. In doing so, we highlight a few key studies that have creatively integrated both historical geographic and genetic data and argue for the wider incorporation of such explicit integrations in biogeographical studies.

Cyclic glaciations were frequent throughout the Quaternary and this affected species distribution and population differentiation worldwide. The present study reconstructed the demographic history and dispersal routes of Eugenia dysenterica lineages and investigated the effects of Quaternary climate change on its spatial pattern of genetic diversity. A total of 333 individuals were sampled from 23 populations and analysed by sequencing four regions of the chloroplast DNA and the internal transcribed spacer of the nuclear DNA. The analyses were performed using a multi-model inference approach based on ecological niche modelling and statistical phylogeography. Coalescent simulation showed that population stability through time is the most likely scenario. The palaeodistribution dynamics predicted by the ecological niche models revealed that the species was potentially distributed across a large area, extending over Central-Western Brazil through the last glaciation. The lineages of E. dysenterica dispersed from Central Brazil towards populations at the northern, western and south-eastern regions. A historical refugium through time may have favoured lineage dispersal and the maintenance of genetic diversity. The results suggest that the central region of the Cerrado biome is probably the centre of distribution of E. dysenterica and that the spatial pattern of its genetic diversity may be the outcome of population stability throughout the Quaternary. The lower genetic diversity in populations in the south-eastern Cerrado biome is probably due to local climatic instability during the Quaternary.

Climatic oscillations acted as an essential factor in molding the distribution and composition of Neotropical biota. However, their effects on the South American Chaco are still poorly known. In this work, we present an updated collection of records of one of its flagship species, Tolypeutes matacus. We analyze the species' range dynamics in current and past scenarios to unveil the effects of past changes over the Chacoan biota. We construct three niches, one with current data (current niche), the other using Pleistocenic occurrence data and predictors from the Last Glacial Maximum (glacial niche), and the last one combining current and Pleistocene data to generate a multitemporal niche. Niches were projected to Current, Mid-Holocene, Last Glacial Maximum, and Last Interglacial scenarios. We obtain 398 records for the species, corresponding to current, historical, Holocene, and Pleistocene records. Current distribution occurs mainly in the currently Chaco region. For current niche reconstructions, suitable areas were smaller than those found nowadays, mainly during the Last Interglacial and Last Glacial Maximum. Holocene reconstruction recovers a distribution of suitable areas pretty similar to the present times. In contrast, glacial niche projection shows higher suitability values in the Pampean Region in all periods analyzed. Multitemporal niche projections showed similar results to those obtained from the current niche projections. Climatic oscillations seem to have significantly impacted the distribution of the species, generating retractions during past times and a period of range stability since the Holocene. Differences between niche projections suggest that Pampean populations may have evolved in different conditions than those from the Chacoan region.

Aim: In New Caledonia, relictual angiosperm lineages are over-represented. However, the mechanisms responsible for such a distribution remain unclear. Two key hypotheses are that: (1) the diversity reflects adaptation to ultramafic substrates that ecologically filtered plant colonists; and (2) the diversity stems from wet climatic conditions that have persisted in New Caledonia during the late Quaternary while Australia and some nearby islands experienced widespread extinction events. Here, we investigate which hypothesis better explains the disharmony of relict angiosperms in New Caledonia. Location: New Caledonia (South West Pacific Ocean). Methods We built species distribution models from herbarium data to determine the environmental correlates for 60 relict angiosperm taxa. Environmental variables used to characterize habitats included vegetation, substrate, and climate variables. We then tested whether the variety of xylem conduit structures borne by New Caledonian relict angiosperms, which is expected to affect plant hydraulic capacity, was correlated with habitat preference. Finally, we analysed species prevalence on different substrates and projected habitat size and distribution to the Last Glacial Maximum (LGM). Results: We found a clear habitat preference among relict angiosperms for rain forests located on non-ultramafic substrates, with the exception of taxa bearing true vessels with simple perforation plates, which harboured a wider habitat breadth. We also showed that these rain forest habitats experienced a range reduction and an eastward shift during the LGM, forming two refugial areas located on the warm and rainy east coast of Grande Terre. Main conclusions: Prevalence of relict angiosperms in habitats characterized by low evaporative demand appears to be related to xylem hydraulic limitations. The disharmony of relict angiosperms in New Caledonia therefore arose from the persistence of rain forests in the island despite global fluctuations in climate during the Quaternary that affected floras in the region. Our study offers a new model to explain why certain angiosperm families are disharmonically represented in New Caledonia.