Endemic Chilean Rodents Vanish After Record-Breaking 2019 Drought, Study Finds

Scientists analyzing more than a decade of field data have documented the sudden disappearance of a once‑abundant population of degus, the native rodent of central Chile, following the country’s most severe drought in recent history.

The findings, published in the peer‑review journal Ecology, draw on 12 years of systematic population monitoring. Researchers observed that the degu community endured a prolonged megadrought that stretched across nearly ten years, maintaining stable numbers despite shrinking water sources and reduced vegetation.

Degus, small burrowing rodents that play a key role in seed dispersal and soil aeration, have long been considered resilient to the variable climate of the Mediterranean‑type region of central Chile. Their ability to survive the earlier megadrought was attributed to behavioral flexibility, such as shifting foraging patterns and exploiting deeper soil moisture reserves.

However, the extreme drought event of 2019 proved overwhelming. Field surveys conducted after that year recorded a sharp decline, with the species disappearing from several monitoring sites entirely. The rapid collapse suggests that the drought exceeded the physiological and ecological thresholds that the rodents could tolerate, leading to local extirpation.

The study underscores how climate extremes can outpace the adaptive capacity of wildlife, even for species previously deemed hardy. Chile has experienced a series of low‑precipitation years linked to broader Pacific Ocean warming patterns, and the 2019 event marked a new intensity level. Such conditions not only threaten individual species but also disrupt the broader ecosystem functions that rodents support.

Researchers stress that continued long‑term monitoring is essential to detect early warning signs in other vulnerable taxa. Conservation strategies may need to incorporate habitat restoration, supplemental water sources, or assisted migration to mitigate the impacts of future megadroughts. The degu case provides a stark illustration of how escalating climate variability can translate into tangible losses in biodiversity, prompting a reassessment of resilience assumptions for wildlife across arid and semi‑arid landscapes.