Pablo Guerrero has spent his entire life exploring the cacti of the Atacama Desert, initially on family excursions to the Chilean coast and later as a researcher investigating the effects of climate change and illegal poaching on the delicate flora. The desert, known as the driest place on Earth outside of the planet's poles, is so barren that NASA utilizes it to test Mars rovers. However, from a young age, Guerrero learned to identify patches of life concealed within the arid terrain.
Cacti, with their diverse shapes and vibrant flowers, quickly became his passion. Guerrero began his research in the Atacama in the early 2000s, observing the plants of his childhood with a botanist's perspective. Their resilience in such harsh conditions impressed him, and he became increasingly concerned about their ability to survive as human activity encroached on the desert.
"Encountering these plants, particularly those facing conservation issues, was a profound moment for me," says Guerrero, now a botanist at the Universidad de Concepción in Chile. Cacti in the Atacama are especially susceptible to disturbances. Many species are confined to small areas, and in the desert's driest regions, cacti rely solely on fog for water. Yet, the desert is growing hotter and drier, with fog disappearing in some areas.
Human impact on the desert is also escalating. In Guerrero's youth and early research years, reaching remote biodiversity hotspots required arduous treks on foot. As mining and energy industries expanded, more roads were constructed, transforming lengthy journeys into quick drives. Litter now accumulates along these roads, and once-thriving areas feel desolate, marked by the desiccated remains of cacti. Due to the desert's dryness, these remains decompose slowly and persist for years. Many cacti populations are now sparse.
"Comparing current populations with historical photos taken by a botanist, it's clear to see the decline in plant abundance," he notes. "They are far less numerous now."
In recent years, Guerrero has heard from colleagues about increased seizures of cacti at the Chilean border. The global interest in cacti as houseplants has surged, leading to more theft. From the American Southwest to South Africa, desert plants have become targets of poaching. Even the remote Atacama was not immune.
Guerrero sought to understand how poaching was impacting the desert's cacti. He focused on Copiapoa, a genus of cacti predominantly found in the Atacama, which has become highly sought after in recent years. From his field visits, it was evident that many species were at risk, if not already on the brink of extinction. In the 2015 assessment, 28 percent of Copiapoa species and subspecies were classified as critically endangered or endangered. However, nearly half of the 39 known species and subspecies had not been evaluated.
Guerrero aimed to rectify this by using new evolutionary histories, detailed mapping, and expert consultation to reassess Copiapoa's extinction risk. The findings were alarming: 76 percent of all Copiapoa species and subspecies are now critically endangered or endangered, significantly higher than the 2015 assessment. Guerrero then analyzed factors contributing to extinction risk, including landscape condition, human footprint, plant poaching, and legal trade. Climate change was a factor, but poaching and trade emerged as the most significant threats, affecting nearly all critically endangered species, as reported in the October issue of Conservation Biology.
"The situation is dire," Guerrero states. Determined to aid in the conservation of Atacama's cacti, he is investigating the factors that enable them to survive in the desert and collaborating on national and international efforts to document poaching. He believes establishing new conservation areas with high biodiversity and training park rangers to recognize rare cacti are crucial steps.
However, the rapid escalation of extinction risk for Atacama's cacti deeply concerns Guerrero. "I fear for the future of some of these species," he admits.
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