A groundbreaking revelation into the catastrophic repercussions of one of Earth’s most devastating events has emerged from a research team led by USC Dornsife College of Letters, Arts and Sciences. Unveiling profound insights into the end-Triassic mass extinction, their findings transcend mere historical analysis, providing crucial lessons for contemporary environmental challenges.
Approximately 200 million years ago, our planet witnessed its fourth major mass extinction event. Triggered by a surge in greenhouse gases stemming from volcanic activity, this event induced rapid global warming and a profound transformation in the planet’s biosphere, marking the conclusion of the Triassic period and heralding the Jurassic. Today, many scientists argue that Earth is currently amidst another mass extinction, primarily propelled by analogous climate changes.
Taking a distinctive approach, Earth scientists at USC Dornsife employed a novel “ecospace framework” method to assess the impact of this extinction event on both ocean and land ecosystems. This innovative method goes beyond categorizing animals solely by species, incorporating ecological roles and behaviors—from airborne or aquatic predators to grazing herbivores, and from oceanic seafloor invertebrates to terrestrial soil-dwelling creatures.
David Bottjer, professor of Earth sciences, biological sciences, and environmental studies at USC Dornsife and a senior author of the study, explained, “We wanted to understand not just who survived and who didn’t, but how the roles that different species played in the ecosystem changed. This approach helps us see the broader, interconnected ecological picture.”
This collaborative study, involving both students and faculty from USC Dornsife and the Natural History Museum of Los Angeles County, has been published in the Proceedings of Royal Society B. The research not only sheds light on the intricate dynamics of the past but also serves as a guiding beacon for comprehending and addressing the pressing environmental challenges of our time.
Sea life suffered, but not as much as land animals
The study brought to light a striking divergence in the repercussions on marine and terrestrial ecosystems. While both realms endured substantial losses, the research indicates that land-based ecosystems bore a more severe impact, enduring prolonged instability.
In the oceans, an alarming 71% of genera, representing various species, disappeared. Intriguingly, despite this extensive loss, the overall structure of marine ecosystems demonstrated resilience. Predators such as sharks, ammonites, a type of mollusk, and filter feeders like sponges and brachiopods, though significantly affected, ultimately exhibited a capacity for recovery.
On terra firma, the outlook was considerably grimmer. An astonishing 96% of terrestrial genera faced extinction, leading to a profound reconfiguration of Earth’s life tapestry. Large herbivores like early dinosaurs and diverse small predators experienced substantial setbacks, with noteworthy alterations in their populations and roles within the ecosystem.
Co-lead author Alison Cribb, who recently earned her Ph.D. in geological sciences at USC Dornsife and is now affiliated with the University of Southampton in the U.K., remarked, “This contrast between land and sea tells us about the different ways ecosystems respond to catastrophic events. It also raises important questions about the interplay of biodiversity and ecological resilience.”
Climate change clues from ancient catastrophe
Beyond merely piquing historical curiosity, the study’s findings hold substantial implications for our contemporary environmental challenges. Co-lead author Kiersten Formoso, nearing completion of her doctoral studies in vertebrate paleobiology at USC Dornsife and soon to join Rutgers University, emphasized, “Understanding past mass extinctions helps us to predict and possibly soften the impacts of current and future environmental crises.”
The parallels drawn between the rapid global warming during the end-Triassic and today’s climate change are particularly noteworthy. David Bottjer, co-lead author and professor of Earth sciences, biological sciences, and environmental studies at USC Dornsife, pointed out, “We’re seeing similar patterns now—rapid climate change, loss of biodiversity. Learning how ecosystems responded in the past can inform our conservation efforts today.”
Moreover, the research provides a rare glimpse into a world that existed over 200 million years ago, effectively serving as a time machine. Bottjer remarked, “It’s like a time machine, giving us a glimpse of life during a period of profound change.”
The study’s innovative ecospace framework, focusing on functional roles, introduces a fresh perspective on ancient life, as noted by Frank Corsetti, professor of Earth sciences and chair of USC Dornsife’s Department of Earth Sciences. Corsetti emphasized, “It’s not just about identifying fossils. It’s about piecing together the puzzle of ancient ecosystems and how they functioned.”
Future ventures will delve into the past’s lessons
As the scientists chart their course for additional research, their focus extends to unraveling the recovery mechanisms of various species and ecosystems post-extinction. The intention is to draw parallels between these ancient events and the contemporary challenge of biodiversity loss driven by climate change.
The roadmap for future studies includes an exploration of ecospace dynamics across other epochs marked by significant environmental shifts in deep time. Co-lead author Alison Cribb expressed the sentiment, “We’ve just scratched the surface. There’s so much more to learn about how life on Earth responds to extreme changes, and this new ecospace framework offers great potential for helping us do that.”
Pandemic sparks unique, collaborative project
The inception and substantial progress of the study occurred amid the backdrop of the COVID-19 pandemic, during a period when restrictions hampered many other forms of research, noted Bottjer. He highlighted, “This produced unique conditions that fostered and led to the development and completion of this research involving individuals with expertise across a broad variety of paleobiological fields, from microbes to invertebrates to vertebrates, in marine and terrestrial environments, with everyone working together towards one goal.”
Bottjer credited co-authors Alison Cribb and Kiersten Formoso for spearheading the collaboration, under his and Frank Corsetti’s supervision, with essential contributions from other co-authors integral to the study’s success.