Rising mountains do more than reshape the landscape – they also drive evolutionary change, according to a new study. By simulating millions of years of tectonic uplift, researchers have uncovered a link between mountain building and biodiversity, shedding light on how Earth’s dynamic topography shapes biodiversity over deep time. Mountain ranges are widely recognized as global hotspots of terrestrial biodiversity yet only cover a relatively small proportion of the Earth’s surface, suggesting a strong connection between topographic evolution and species diversity. Mountainous terrain can promote speciation by isolating populations, fostering genetic divergence, and enabling adaptive radiations across diverse ecological niches. Additionally, landscape changes driven by tectonics, climate, and river dynamics influence species distributions over time. However, the evolutionary mechanisms that drive the link between mountain uplift and topography on biodiversity are poorly understood. Using coupled landscape and biological models and a novel biologically simplified speciation algorithm, Eyal Marder and colleagues investigated how mountain-building processes alone shape biodiversity over geological timescales. Using the model, Marder et al. simulated various mountain-building scenarios over 20 million years to examine how species richness patterns responded to realistic tectonic uplift rates. They found that tectonic and geomorphological activity not only shapes species richness in high-elevation mountain regions but also leaves detectable imprints in adjacent lowland basins. According to the model’s findings, species richness increases in direct proportion to the magnitude and pace of mountain building, as well as the pace of topographic development, which are all influenced by tectonic rock uplift rates. Moreover, Marder et al. show that speciation lags the onset of mountain building, with species richness reaching equilibrium once topographic relief stabilizes. While erosional highlands foster higher species richness likely due to population isolation, species richness remains strongly correlated between highlands and lowlands, suggesting that lowland biodiversity dynamics mirror those in adjacent mountain ranges. According to the authors, the alignment between the model’s results and real-world biodiversity patterns highlights the significant role of topography and tectonics in shaping biodiversity.

Challenging long-held assumptions about global terrestrial carbon storage, a new study finds that the majority of carbon dioxide (CO₂) absorbed by ecosystems has been locked away in dead plant material, soils, and sediments, rather than living biomass, researchers report. These new insights, which suggest that terrestrial carbon stocks are more resilient and stable than previously appreciated, are crucial for shaping future climate mitigation strategies and optimizing carbon sequestration efforts. Recent studies have shown that terrestrial carbon stocks are increasing, offsetting ~30% of anthropogenic carbon dioxide emissions. A primary mechanism driving this trend is the CO₂ fertilization effect, in which elevated atmospheric CO₂ levels enhance plant productivity. However, it is uncertain how much organic carbon is stored in living biomass versus nonliving organic reservoirs, such as plant detritus, soils, and sediments. Understanding this distribution is crucial because different pools have varying carbon residence times and vulnerabilities to environmental change. Nevertheless, accurately quantifying living and nonliving carbon storage pools has proven difficult. To address this challenge, Yinon Bar-On and colleagues developed a comprehensive assessment of global changes in woody vegetation carbon stocks by harmonizing diverse remote-sensing estimates with upscaled field inventory data from 1992 to 2019. This integrated approach allowed the authors to partition terrestrial carbon accumulation between living biomass and nonliving organic reservoirs providing a more complete understanding of carbon distribution across ecosystems. Bar-On et al. discovered that while terrestrial ecosystems accumulated approximately 35 ± 14 gigatons of carbon (GtC) during the study period, global living biomass stocks increased by only about 1 ± 7 GtC. The findings indicate that most of the carbon sequestered over the last 3 decades was stored as nonliving organic matter in soils, deadwood, and human-influenced reservoirs like dams and landfills. These pools persist far longer than living biomass, suggesting that terrestrial carbon storage may be more stable over time than previously assumed. “Although the study of Bar-On et al. primarily focused on woody biomass because of its large carbon stocks, the role of grass-dominated ecosystems, where soil carbon sequestration is the dominant storage mechanism, merits further investigation,” writes Josep Canadell in a related Perspective. “A more regional and ecosystem-based analysis will further provide key insights to enable the design of strategies for the conservation of carbon stocks and enhancement of CO₂ sinks for climate mitigation.”

Humans’ unique language capacity was present at least 135,000 years ago, according to a survey of genomic evidence. As such, language might have entered social use 100,000 years ago.