Investigators from the CONICET analyzed how forest fires affect water quality in Patagonian mountain streams.
The work, published in the journal Science of The Total Environment, focused on the large fire that occurred in 2021 near Las Golondrinas and El Hoyo (Chubut), which affected more than 13,000 hectares of Andean-Patagonian forest.
The team from CIEMEP (CONICET-UNPSJB), together with specialists from INVAP, monitored for 28 months the dynamics of nutrients and water quality in burned basins, comparing four affected streams with four reference streams.
Main findings
- Disturbance window: critical period immediately after the fire, where the first rains wash away ashes and particles. Marked increases in electrical conductivity and water turbidity were recorded.
- Phosphorus: concentrations up to 17 times higher than in reference sites during the first months.
- Nitrates: sustained increase over three years, due to the reduced capacity of burned vegetation to absorb nutrients.
- Heavy metals: increases detected even in unburned streams, probably due to airborne particle transport.
Ecological consequences
The results show that fires not only affect terrestrial vegetation and fauna but also aquatic ecosystems:
- They alter the trophic structure and nutrient dynamics.
- They reduce water quality for human consumption.
- They compromise the resilience of ecosystems to climate change.
Importance of monitoring
The researchers emphasize that headwater streams are essential for:
- Water supply for local communities.
- Economic activities such as livestock and forestry use.
- Conservation of aquatic biodiversity.
The continuous monitoring initiated in June 2021 allowed for the identification of long-term trends and underscores the need to implement management strategies that include livestock exclusion, regulation of forestry use, and fire control.
Projections and new studies
The recent fires in Los Alerces National Park (2024 and 2026) offer new opportunities to expand research and answer questions about the variability of impacts according to the extent of the fire, topography, and type of vegetation cover.
The study confirms that forest fires have profound and lasting effects on the water bodies of Patagonia. The sustained elevation of nutrients and metals can alter ecosystem health and compromise the health security of communities.
The research highlights the urgency of strengthening monitoring and integrated watershed management to address a phenomenon that is intensifying with climate change and the expansion of inhabited areas into natural areas.
