The formation of the Isthmus of Panama allowed for migrations between the once separated continents of North and South America. This led to one of the greatest documented interchanges of biota in Earth history, wherein an array of species across many groups migrated between the continents. Glyptotherium , a giant extinct armadillo‐like grazer, is an example of a taxon that likely originated in South America and migrated to North America. Here we use Ecological niche modeling to test the extent of suitable conditions for Glyptotherium in Central America and surrounding regions during the intervals when the taxon is thought to have dispersed, allowing for assessment of plausible migration routes and the hypothesis that the genus migrated from North America back to South America during the Rancholabrean (14 000–240 000 years ago). Our niche modeling results show suitable abiotic conditions for Glyptotherium in Central America and the surrounding area throughout the Plio‐Pleistocene, with western South America (the ‘high road') suggested as their ancestors' route northwards. Depending on the extent of suitable conditions, it may have been possible for Glyptotherium to return to South America during the Rancholabrean. The results support previous hypotheses that the range of Glyptotherium was constrained by the need for warm, wet environments.
The datasets contain all the dataset and scripts used to generate the figures with the title "Ecological niche conservatism spurs diversification in response to climate change", which is going to be online on Nature Ecology & Evolution soon.AbstractA longstanding debate has focused on the relationship between evolutionary innovation in ecological niches of species and rates of biological diversification of those species. As such questions across broad scales of time and space, short-term experiments or scattered fossil evidences are not feasible, and contrasting opinions have emerged: niche innovation might allow species to explore and colonize new geographic areas across which they could speciate, or niche conservatism might augment isolation of populations that could then undergo allopatric speciation. Here, we used an in silico, “virtual world” simulation approach to address these questions. First, we created biological worlds on global scale in which different types of niche evolution could and could not occur, and then examined the resulting virtual species assemblages in terms of levels and patterns of diversity. The outcome was clear: niche conservatism promotes biological diversification, whereas labile niches—whether adapting to conditions available or changing randomly—led to slower diversification rates. This outcome, in the context of burgeoning theoretical and empirical evidence for niche conservatism, provides a framework for understanding how Earth-life interactions produced such a diverse biota.
The decline in species richness from the equator to the poles is referred to as the latitudinal diversity gradient (LDG). Higher equatorial diversity has been recognized for over 200 years, but the consistency of this pattern in deep time remains uncertain. Examination of spatial biodiversity patterns in the past across different global climate regimes and continental configurations can reveal how LDGs have varied over Earth history and potentially differentiate between suggested causal mechanisms. The Late Permian–Middle Triassic represents an ideal time interval for study, because it is characterized by large-scale volcanic episodes, extreme greenhouse temperatures and the most severe mass extinction event in Earth history. We examined terrestrial and marine tetrapod spatial biodiversity patterns using a database of global tetrapod occurrences. Terrestrial tetrapods exhibit a bimodal richness distribution throughout the Late Permian–Middle Triassic, with peaks in the northern low latitudes and southern mid-latitudes around 20–40° N and 60° S, respectively. Marine reptile fossils are known almost exclusively from the Northern Hemisphere in the Early and Middle Triassic, with highest diversity around 20° N. Reconstructed terrestrial LDGs contrast strongly with the generally unimodal gradients of today, potentially reflecting high global temperatures and prevailing Pangaean super-monsoonal climate system during the Permo-Triassic.
Data supporting "Climatic shifts drove major contractions in avian latitudinal distributions throughout the Cenozoic". Supporting data include the environmental layers used to calibrate present-day ecological niche models, and median ecological niche models generated from Maxent from the ten bootstrap replicates for each neornithine clade.
The Arctic tundra biome is undergoing rapid shrub expansion ("shrubification") in response to anthropogenic climate change. During the previous ~2.6 million years, glacial cycles caused substantial shifts in Arctic vegetation, leading to changes in species' distributions, abundance, and connectivity, which have left lasting impacts on the genetic structure of modern populations. Examining how shrubs responded to past climate change using genetic data can inform the ecological and evolutionary consequences of shrub expansion today. Here we test scenarios of Quaternary population history of dwarf birch species (Betula nana L. and Betula Glandulosa Michx.) using SNP markers obtained from RAD sequencing and approximate Bayesian computation. We compare the timings of population events with ice sheet reconstructions and other paleoenvironmental information to untangle the impacts of alternating cold and warm periods on the phylogeography of dwarf birch. Our best supported model suggested that the species diverged in the Mid-Pleistocene Transition as glaciations intensified, and ice sheets expanded. We found support for a complex history of inter- and intraspecific divergences and gene flow, with secondary contact occurring during periods of both expanding and retreating ice sheets. Our spatiotemporal analysis suggests that the modern genetic structure of dwarf birch was shaped by transitions in climate between glacials and interglacials, with ice sheets acting alternatively as a barrier or an enabler of population mixing. Tundra shrubs may have had more nuanced responses to past climatic changes than phylogeographic analyses have often suggested, with implications for future eco-evolutionary responses to anthropogenic climate change.
Most spiders use venom to paralyze their prey and are commonly feared for their potential to cause injury to humans. In North America, one species in particular, Loxosceles reclusa (brown recluse spider, Sicariidae), causes the majority of necrotic wounds induced by the Araneae. However, its distributional limitations are poorly understood and, as a result, medical professionals routinely misdiagnose brown recluse bites outside endemic areas, confusing putative spider bites for other serious conditions. To address the issue of brown recluse distribution, we employ ecological niche modeling to investigate the present and future distributional potential of this species. We delineate range boundaries and demonstrate that under future climate change scenarios, the spider's distribution may expand northward, invading previously unaffected regions of the USA. At present, the spider's range is centered in the USA, from Kansas east to Kentucky and from southern Iowa south to Louisiana. Newly influenced areas may include parts of Nebraska, Minnesota, Wisconsin, Michigan, South Dakota, Ohio, and Pennsylvania. These results illustrate a potential negative consequence of climate change on humans and will aid medical professionals in proper bite identification/treatment, potentially reducing bite misdiagnoses.
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