Smallholders as agents of ecosystem repair: Trajectories of rapid carbon and trophic recovery in the agroecological habilitation of degraded volcanic soils (cangahua) in the Andes

The habilitation of indurated volcanic ash soils (locally known as cangahua ) in the high Andes is conventionally viewed as a physical challenge. Consequently, reclamation efforts prioritize mechanical tillage and external inputs, or degraded land is simply abandoned, often resulting in arrested successional states. This paper presents a 25-year chronosequence of smallholder regenerative agroecology at the Ilaló Volcano, Ecuador, testing the hypothesis that the recovery of these degraded soils is constrained by interrelated biological and physical limitations, rather than physical hardness alone. Utilizing a five-stage successional matrix—ranging from sterile parent material at Ground Zero (degraded) and Passive Regeneration (fallow) plots to Conventional (traditional) agriculture, Active Regeneration (agroecology) plots, and a Native Forest (ecological reference)—we evaluate the geochemical and trophic trajectory of holistic soil bioactivation. Results indicated that active biological management was strongly associated with multiplying the baseline Soil Organic Carbon (SOC) by 6.1 times (from 0.62% to 3.80%), successfully recovering 54% of the Native Forest’s SOC-carrying capacity. This rapid accumulation of organic matter yielded an estimated drawdown rate of 14.0 t CO₂e ha⁻¹ yr⁻¹. Furthermore, the biological data illuminated three specific ecological dynamics: 1) Passive Regeneration plots failed to sequester deep carbon but served as vital landscape-level biological incubators for primary detritivores (Oribatida); 2) macrofauna (e.g., earthworms) appeared to function as biological plows that actively built structural macro-porosity in the cemented ash; and 3) Active Regeneration plots achieved "predator parity," demonstrating a carrying capacity for apex predators (Mesostigmata) statistically equivalent to the Native Forest reference. We propose an integrated physiological framework to explain this ecological succession, suggesting that, when regenerative, smallholder agroecological farmers are capable of ecosystem repair through biological system activation. Scaling this intervention across the 181,486 ha of superficial cangahua in the Ecuadorian Sierra reveals a carbon sink equivalent in magnitude to approximately 30% of Ecuador's unconditional emission-reduction targets under the Paris Agreement. Because this extrapolation represents a theoretical biophysical maximum, we emphasize the need for longitudinal, landscape-scale research to rigorously test these dynamics across diverse Andean micro-climates and confirm farmer-led agroecology as a scalable Natural Climate Solution.