A study led by Miguel Hernández University reveals alarming soil degradation in Peru’s Andes post-wildfire, underscoring the fragile ecosystem’s vulnerability and the urgent need for mitigation strategies.
September 2018 marked a catastrophic event for the Peruvian Andes when nearly 2,000 hectares of shrubland on the Pichu Pichu volcano were consumed by a wildfire. Unlike Mediterranean regions where vegetation has evolved to withstand frequent fires, the volcanic soils of Arequipa, one of the world’s driest areas, are ill-prepared for such disturbances. This event has led to significant ecological ramifications, with the soil and vegetation suffering notable degradation.
A dedicated research team led by Miguel Hernández University of Elche (UMH) conducted an in-depth analysis of the affected area at an altitude of 3,700 meters. Now, their findings — published in the Spanish Journal of Soil Science — paint a stark picture.
Four years post-fire, the soil retains severe combustion scars, compounded by subsequent erosion, that have critically depleted soil organic carbon (SOC), a vital component of soil fertility.
Ecosystem-Specific Fire Dynamics
“The Peruvian Andes are not prepared for wildfires,” Jorge Mataix Solera, a professor of soil science at UMH who brings over three decades of experience in post-fire soil recovery, said in a news release.
While fire is a natural ecological force, its impact varies significantly by ecosystem. In Pichu Pichu, soil has endured chemical and physical degradation, inhibiting ecological recovery and further reducing soil cohesion and fertility.
Particularly problematic is the post-fire enhancement of the soil’s natural water repellency. High sand content and specific organic matter characteristics exacerbate this issue, causing rainwater to run off instead of soaking into the soil.
“[U]nderstanding the effects of fire on these young and fragile soils is crucial,” added Minerva García Carmona, an assistant professor at UMH.
Focus on Native Flora
The researchers scrutinized the effects on two native shrub species: Berberis lutea, known locally as “palo amarillo del Perú,” and Parastrephia quadrangularis, or “tola.”
They discovered that soils dominated by Berberis lutea experienced more severe degradation, likely due to its higher biomass intensifying combustion effects.
An Ecosystem in Peril
The Pichu Pichu region is a “cold desert,” receiving an average annual precipitation of just 385 mm, mostly within a brief three- to four-month window. Temperatures fluctuate between 4 and 18 degrees Celsius, and the local vegetation is comprised largely of drought-resistant shrubs.
Despite its sparse vegetation, Pichu Pichu’s foothills support forests that are biodiversity hotspots, including endangered Polylepis species.
Rising Wildfire Incidence and Climate Change
A concerning trend has emerged, with Peru experiencing a record 7,037 wildfire hotspots in September 2024 alone, according to the Queimadas fire monitoring project. This escalation is closely linked to the broader climate crisis, necessitating urgent strategies for fire prevention and post-fire recovery.
In a desert environment like Arequipa, “understanding soil response under new fire regimes is essential for assessing ecosystem resilience to climate change,” according to a UMH researcher.
It is crucial to mitigate the effects of rising temperatures and intensified droughts, Mataix noted.
“This is as crucial in Peru as it is in Spain or California,” Mataix concluded. “Although fire is a natural phenomenon, the climate crisis is exacerbating these events, and we must do everything possible to restore and protect these ecosystems.”
The study emphasizes the immediate need for environmental protection measures, shedding light on the pressing impacts of climate change on already vulnerable ecosystems.