In a groundbreaking study that delves into the intricate relationship between evolutionary history and the spatial extent of species’ habitats, researchers from some of Europe’s foremost biodiversity institutions have unveiled compelling evidence linking the age of a species to the size of its geographic range. This extensive analysis, encompassing over 26,000 species across seven major taxonomic groups—including mammals, birds, reptiles, amphibians, reef fishes, palms, as well as terrestrial and marine mammals—provides a nuanced understanding of how evolutionary time and dispersal abilities interplay to shape biodiversity patterns globally.
At the core of this investigation lies the hypothesis that older species tend to inhabit larger ranges simply because more time has allowed them to disperse, adapt, and proliferate across diverse environmental niches. While intuitively appealing, this idea had remained largely unproven on a vast scale until this meta-analysis emerged. Leveraging a combination of phylogenetic data, geographical range information, and species-specific traits, the study rigorously tested the correlation between evolutionary age and present-day distributional extent.
One of the standout findings of this research is the consistent pattern across nearly all examined taxa—species that have persisted longer in evolutionary history generally exhibit broader distributions. This trend likely arises from older lineages having had prolonged opportunities to overcome geographic barriers, exploit a variety of habitats, and evolve traits conducive to wide dispersal. However, an exception to this trend was identified within marine mammals, where such age-range correlations were absent, hinting at distinctive ecological or evolutionary constraints within aquatic environments that merit further exploration.
Beyond the simple age factor, the researchers highlight the crucial modulatory role of species’ dispersal capabilities. It is not merely the length of evolutionary time that dictates range size but also how effectively species can traverse obstacles and colonize new areas. Birds characterized by aerodynamic wing morphology optimized for long-distance flight, and palms producing substantial fleshy fruits dispersed by large vertebrates capable of wide foraging ranges, exemplify this phenomenon. Such species can rapidly achieve extensive distributions, effectively outpacing less mobile counterparts irrespective of their evolutionary tenure.
Particularly telling is the amplified importance of evolutionary age in less dispersive groups like amphibians. These organisms, often limited by physiological constraints such as sensitivity to desiccation and temperature, show a stronger dependency on the duration since origin to explain their range sizes. Their movement limitations mean that the expansion of territories is a slow process, governed primarily by evolutionary time rather than quick colonization events.
The geographic context, especially the distinct nature of island ecosystems, further complicates the relationship between age and range size. The study reveals that species restricted to islands possess overall smaller ranges due to the inherent spatial constraints of insular environments. Surprisingly, the difference in range sizes between older and younger island species is more pronounced than in continental settings. This observation suggests that early island colonizers, often freed from predation and competitive pressures prevalent on mainlands, could exploit ecological opportunities to broaden their geographical presence more significantly over time.
Underlying these spatial dynamics is the pressing issue of extinction risk related to geographic range sizes. It is well-established that species confined to narrow ranges face heightened vulnerability due to reduced population sizes and increased sensitivity to habitat disturbances. The research accentuates that understanding the evolutionary determinants of range sizes can therefore inform conservation prioritization. Recognizing which species are predisposed to limited distributions—and hence higher endangerment—based on their phylogenetic age and dispersal traits could lead to more targeted and effective preservation strategies.
Moreover, the escalating velocity of anthropogenic environmental changes introduces a new layer of complexity. Species with limited ranges may lack the resilience or genetic variability to adapt rapidly to shifting climatic and habitat conditions. Interestingly, the study posits that older species, by virtue of their extended evolutionary histories, may harbor genetic architectures favorable for adaptation and survival despite environmental upheavals. This tantalizing hypothesis opens avenues for integrating genomics with ecological modeling to forecast species responses under future global change scenarios.
The integrative nature of this research owes much to the collaborative efforts of institutions such as the German Centre for Integrative Biodiversity Research (iDiv), Leipzig University, and Naturalis Biodiversity Center. Their approach exemplifies how synthesizing disparate datasets—ranging from phylogenies to ecological traits—can yield insights unattainable through isolated studies. Central to this synthesis was the involvement of Dr. Adriana Alzate, whose leadership harnessed the power of iDiv’s synthesis center (sDiv) to bridge data gaps and apply sophisticated analytical frameworks to vast biodiversity records.
Importantly, the study transcends purely academic implications by directly engaging with conservation challenges. Highlighting how ecological traits and evolutionary history intertwine to govern species distributions, the research offers practical guidance for biodiversity monitoring. It calls attention to the nuances between taxa—a ‘one size fits all’ conservation approach may neglect critical differences in dispersal and adaptability. Particularly on islands, where species’ ranges are intrinsically limited, preserving these unique evolutionary lineages may require specialized frameworks accounting for their distinctive environmental contexts.
While this study provides a robust foundation for understanding the drivers of species range sizes, it also charts a path for future research. The suggestion to incorporate genetic data into assessments holds promise for revealing mechanisms by which older species may maintain wider distributions and adapt to environmental challenges. As genomic technologies and ecological data increasingly converge, there lies potential to unravel the molecular underpinnings of adaptability and dispersal—key traits that ultimately determine the fate of species in an era dominated by human-induced change.
In sum, this extensive cross-taxon analysis offers a compelling narrative linking evolutionary age, dispersal ability, and geographic range—a triad fundamental to biodiversity science. By elucidating how these factors interact, the research enriches our understanding of species ecology and evolution while providing actionable insights into conservation biology. As global biodiversity faces mounting threats, such integrative studies are invaluable tools to safeguard the myriad forms of life that grace our planet.
Subject of Research: Evolutionary determinants of species range size across diverse taxa and their implications for extinction risk and conservation.
Article Title: Evolutionary age correlates with range size across plants and animals
News Publication Date: 23-Aug-2025
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Image Credits: Joseph Tobias
Keywords: Evolutionary age, species range size, dispersal ability, biodiversity, extinction risk, phylogenetics, island biogeography, adaptation, conservation biology, species distribution
