Sinkholes Shield Trees in China but Limit Their Evolution

Researchers in China studied Magnolia aromatica, an endangered tree, and discovered that giant sinkholes, known as tiankeng, protect the trees from heat and drought. The team sequenced the genomes of 112 trees from 26 populations both inside and outside these sinkholes in southwest China’s karst landscape.

They found the sinkholes create cooler, more humid conditions that allow the trees to survive. However, the study revealed a genetic paradox.

While the sinkholes maintain moderate genetic diversity overall, trees within the sinkholes have less genomic diversity and more harmful mutations than trees outside them. This suggests the isolation limits gene flow, hindering the trees’ ability to adapt over time.

Functional analysis showed the trees inside the sinkholes adapted to low light conditions. Simulations predict climate change will worsen the accumulation of harmful mutations, threatening the long-term survival of these populations. Researchers now emphasize the need to protect both the sinkholes and surrounding areas to maintain genetic connectivity.