More than 1,500 people marched through La Paz on Sunday, May 31, to demand protection of Sierra La Laguna, the mountain biosphere reserve that serves as the sole freshwater recharge zone for southern Baja California Sur. The Sierra La Laguna protest was the largest environmental demonstration the state capital has seen in years, and it centers on a question no one in government has yet answered: who is flying helicopters loaded with steel construction materials into the mountains, and who authorized it?
The march began at 5 p.m. at Parque Cuauhtémoc and wound along the malecón to the “La Paloma de Porras” sculpture on the waterfront. Organizers from two civil groups, the Frente Ciudadano en Defensa del Agua y la Vida and Rescate de los Pueblos, sus Tradiciones y su Economía, held a press conference, read a public statement, and conducted a symbolic consultation with marchers. Guillermo Trasviña, president of Rescate de los Pueblos, estimated attendance above 1,500. Participants included students, professionals, environmental collectives, families, and ranchers from mountain communities, some arriving on horseback.
Sierra La Laguna Supplies Water to La Paz, Los Cabos, and Rural Communities
Sierra La Laguna earned UNESCO biosphere reserve designation in 2003. The mountain range rises to over 2,000 meters and captures the only significant rainfall in the arid southern peninsula. Its oak and pine forests filter water into underground aquifers that feed La Paz, Los Cabos, and dozens of smaller communities. CONANP, Mexico’s national protected areas commission, manages the reserve, which spans roughly 112,000 hectares split into a core zone and a surrounding buffer zone.
The reserve has faced development pressure before. In 2014, a Canadian-backed open-pit gold mine called Los Cardones drew mass opposition in La Paz. That fight gave birth to the Frente Ciudadano, which Juan Ángel Trasviña Aguilar, a council member of the group, said now includes 37 organizations, from environmental collectives to professional associations. The mine was ultimately blocked, but the legal battle lasted years and left residents wary of any unexplained activity in the sierra.
This time, the threat is murkier. Residents and activists have documented repeated helicopter flights carrying steel structures and construction materials into areas near the reserve. No government agency has publicly claimed responsibility. No developer has come forward. The flights appear to target zones within or adjacent to the buffer zone, but no environmental impact statement has been made public. That information gap is itself a central grievance: marchers carried signs reading “La sierra no se vende, la sierra se defiende” (“The sierra is not for sale, the sierra must be defended”) and demanded transparency from state and federal authorities.
Activist Reports Death Threats After Documenting Helicopter Flights
Elizabeth Álvarez Rosas, a resident of the mountain community of San Dionisio, has been one of the most visible voices documenting the flights. At Sunday’s rally, she reported receiving death threats tied directly to her public statements about the helicopter activity and the steel materials that remain at the site. Álvarez Rosas called for sustained citizen vigilance and received visible support from the crowd.
Death threats against environmental defenders are a serious and recurring problem across Mexico. Global Witness ranked Mexico among the top five deadliest countries for environmental activists in its 2023 report, with at least 31 defenders killed between 2012 and 2022. In Baja California Sur, threats against activists opposing the Los Cardones mine were also documented during that earlier campaign. The fact that Álvarez Rosas has gone public with the threats, rather than retreating, has made her a focal point of the movement.
The protest also followed a May 29 meeting between organizers and Carlos Esquivel Lacroix, a representative of Fundación Hermandad en Armonía. Organizers read a public statement derived from that meeting at the waterfront rally, though the foundation’s precise role in the sierra activity remains unclear from public statements so far.
Organizers Push for Expropriation of Private Parcels Inside the Reserve
One of the movement’s most concrete demands is the expropriation of privately held land within the sierra. While the biosphere reserve designation restricts certain activities, private parcels still exist within its boundaries. Mexican law allows expropriation for reasons of public utility, but the process requires federal action and is rarely fast. Organizers announced they will continue collecting signatures to pressure legislators on this front.
Fidel Trasviña told the press conference that the coalition is in active discussions with state legislators to pursue legal action, demand formal investigations into the helicopter flights, and request the removal of construction materials already deposited in the mountains. If you rely on municipal water in La Paz or Los Cabos, the aquifers beneath Sierra La Laguna are the source. Any construction activity that disrupts the forest canopy or alters drainage patterns in the recharge zone could reduce the volume of water reaching those aquifers over time.
Organizers announced new mobilization activities in the coming weeks and pledged to maintain public pressure until authorities identify who is behind the construction activity and under what legal authority it proceeds. This story was first reported by Colectivo Pericú.