Deforestation significantly reduces litter fauna by changing litter quantity, complexity and quality at the plant-soil interface

The high deforestation rates of the Arid Chaco forests have reduced tree cover and habitat of species living above and belowground. The effects of deforestation have been widely studied in aboveground organisms, with belowground communities being less understood. Here, we evaluated how deforestation transitions from forest to open landscapes affect litter fauna communities (taxonomic and functional abundance and richness) via changes in litter quantity, complexity, and quality. Deforestation caused a marked reduction in litter quantity and complexity, but not in litter quality. Treeless landscape (hereafter referred as open shrubland) presented lower taxonomic abundance and richness than forests, as well as lower abundance and richness of decomposers and predators. Although most of the changes in litter affected litter fauna, litter quality (e.g., C:N) was the most important driver of taxonomic and functional abundance and richness. These results highlight that litter fauna can be affected by both drastic and subtle changes in litter characteristics driven by modifications in plant communities, since litter is the habitat and food for these organisms. Our findings contribute to a better understanding of the mechanisms by which deforestation transitions affect soil organisms in arid environments. • Arid Chaco deforestation decreased taxonomic abundance and richness of litter fauna. • Deforestation reduced abundance and richness of decomposers and predators. • Small changes in litter C:N explained most litter fauna responses. • Deforestation drastically reduced litter quantity and complexity.