Devastating Rio Doce mining disaster sends shockwaves through earthworm populations.

Area of Science:

• Environmental Science
• Ecology
• Soil Biology

Background:

• The Fundão dam breach caused extensive soil alteration in the Rio Doce watershed.
• Earthworms are crucial for soil structure and dynamics, making their response to disturbances ecologically significant.

Purpose of the Study:

• To assess the impact of mining disaster soil conditions on native and invasive earthworm species richness, abundance, and biomass.
• To understand how altered soil properties affect earthworm community composition in riparian zones.

Main Methods:

• Field sampling of earthworm communities in reference and impacted riparian zones across five municipalities in Minas Gerais.
• Identification of earthworm species and measurement of their biomass.
• Analysis of relationships between soil properties and earthworm abundance.

Main Results:

• Eight earthworm species were identified: two invasive (Amynthas gracilis, Pontoscolex corethrurus) and six native species.
• Native earthworm biomass was approximately five times lower in impacted sites compared to reference sites.
• The mining tailings environment altered soil-earthworm relationships, with native species showing lower tolerance than invasive ones.

Conclusions:

• Native earthworms are less tolerant of post-mining disaster soil conditions, potentially leading to shifts towards invasive species dominance.
• The disruption of soil-fauna interactions highlights long-term ecological consequences of mining.
• Restoration efforts must consider belowground biodiversity and the resilience of native earthworm populations.