Trait networks reveal turnover in Caribbean corals and changes in community resilience through the Cenozoic

The present-day climate crisis is transforming coral reef communities, potentially undermining ecosystem functioning. Evolutionary trade-offs between species traits result in diverse life-history strategies, enabling corals to survive disturbance events through specific adaptive mechanisms. Trait–trait relationship networks offer insights into trait turnover and changing life-history strategies during environmental changes. Paleoecological insights from the fossil records can further illustrate how species adapt to environmental shifts, highlighting resilience traits.

We highlight coral traits that promote resilience in the Caribbean based on fossil occurrences and morphological traits, examining biological determinants of species and trait turnover across the Cenozoic. We use traits that underpin the survival of corals during disturbances, for example, corallite diameter, colony growth form, corallite integration, and budding type. We analyzed species turnover and extinctions with a bipartite network and explored trait turnover with trait–trait co-occurrence networks based on 4268 species records at 421 sites over ~40 Myr.

Our findings support existing evidence that species turnover coincided with major environmental and biogeographic changes across the Cenozoic. Additionally, our results provide new insight into functional changes throughout the Cenozoic. Past cooler climates favored corals with a fast growing and reproducing (competitive) life-history strategy, which boosts short-term success, but also increases susceptibility to diseases and thermal stress. Cenozoic species and trait turnover occurred during environmental change, corroborating expectations of such turnover in the future. We found trait co-occurrence modules associated with competitive and stress-tolerant life-history strategies. The transition from the “greenhouse” (Paleogene) to the “icehouse” (Neogene) climate over ~40 Myr favored competitive traits, which supported fast-growing, shallow reefs. With rising temperatures and declining Acropora in the Caribbean, future reefs may resemble Eocene reefs: dominated by stress-tolerant, slow-growing corals adapted to marginal environments.