The latest axolotl census reveals its survival, but it is urgent to restore its habitat in Xochimilco.

A new census in the Xochimilco wetlands , the axolotl's only home, has yielded troubling results, but also a glimmer of hope. Although traditional fishing failed to capture any specimens, environmental DNA analysis has confirmed that this iconic endemic species of Mexico still survives in the canals. This finding underscores the urgency of redoubling efforts to restore its habitat.

The study led by EC is the first in more than a decade. Preliminary results indicate that the axolotl, whose population declined from an estimated 6,000 individuals per square kilometer in 1998 to just 36 in 2014, is on the brink of extinction due to pollution, urban expansion, and the presence of invasive species such as carp and tilapia.

Environmental DNA technology

The first phase of the census, conducted between September 2024 and February 2025, yielded no axolotl captures using traditional netting methods. However, researchers used an innovative technique: environmental DNA (eDNA) analysis . This methodology detects genetic traces in the water, confirming the species' presence even if it cannot be seen.

"The results confirm what we feared: habitat disturbance is pushing the axolotl to the brink of extinction," explained Dr. Luis Zambrano, director of the Ecological Restoration Laboratory at UNAM. "But having found traces of the axolotl gives us hope for continuing restoration efforts."

Environmental DNA samples revealed that axolotls are only found in canals away from urban activity, where water quality is good and native fish and crustaceans still live, Dr. Esther Quintero, technical director of Conservation International Mexico, told El Economista.

The chinampa-shelter model: A tangible solution

With this data, we know that "the survival of the axolotl depends on the restoration of its habitat," Quintero said. In this sense, the chinampa-refuge project has positioned itself as one of the most effective solutions. This model, developed by UNAM and supported by Conservation International, combines scientific knowledge with the ancestral agricultural techniques of the chinamperos.

The chinampa-refugio system creates safe havens for the axolotls. Biofilters are built at the entrances to the canals with wood, stones, and native plants, improving water quality and preventing the entry of invasive predators.

"We can't save the axolotl without restoring its habitat," Quintero confirms, "and that means collaborating with the people who live and work in these wetlands. Restoring Xochimilco also means reflecting on how we live in cities and the space we leave for nature."

The project already has 21 active chinampas-refugios, and its success has improved not only the conditions for the axolotl, but also for other native species and the quality of life for the local community. "The participating chinampa farmers are entitled to a label that distinguishes their products, creating a value chain that benefits both people and the ecosystem (...) That's why these types of projects should continue and be supported."

The way forward

Researchers hope to complete the census in a second phase, beginning in September 2025 and extending through February 2026. The final results will be used to guide and scale restoration efforts.

The importance of preserving the axolotl goes beyond its charisma. Biologically, it is a keystone species, a top predator that regulates the wetland ecosystem. "Its health is a direct indicator of the health of Xochimilco, a vital place for biodiversity and a natural regulator of Mexico City, providing ecosystem services such as flood control and climate improvement."

The census sends a clear message: the axolotl has not disappeared, but it urgently needs collective action and sustained investment to prevent its final extinction, the specialist concluded.

Methodology of the first phase of the census

• 115 monitoring points were studied across the 2,522 hectares of the protected area. 115 net casts were made.

• 53 environmental DNA samples were taken: 10 within refuge areas and 43 outside them, at 400-meter intervals.

• The samples were analyzed in the Environmental DNA Laboratory of the UNAM Institute of Biology.

The DNA analysis was based on previous work conducted by University College London in collaboration with UNAM, which found traces of axolotls inside the shelters, demonstrating that they can survive in these sites.