Dr Luke Noble1, Reid Tingley1, Andrew Weeks1
1EnviroDNA, Melbourne, Australia
Biography:
Luke is a geneticist and data scientist by training with a background in quantitative evolutionary nematode genomics. After joining EnviroDNA 5 years ago, Luke now oversees R&D and innovation activities at EnviroDNA.
Abstract:
Soil eDNA is increasingly proposed as an indicator of restoration progress. Supporting evidence is accumulating, but studies are often underpowered. Long chronosequences are in short supply, and results vary across diverse locations, data sources, and approaches. The reference condition against which recovery is judged is itself variable and shifting, where repeated measurements have been made.
We generated and integrated data across more than 40 sites on rehabilitated land in Queensland, spanning up to forty-six years, alongside local references. Each was measured using soil physicochemical testing, vegetation condition surveys, soil metabarcoding, and satellite imagery. We asked which measurements distinguish rehabilitated from reference ground, and which follow recovery with age.
Soil chemistry separated rehabilitated from reference ground clearly, but changed little with age. In contrast, soil eDNA diversity rose steadily. Among-site variability was high in the youngest rehabilitation area and fell to reference levels within about fifteen years. Community composition also shifted toward reference, but diversity was a stronger predictor in this case. Vegetation condition surveys and satellite fractional cover tracked age weakly at best once area-level effects were accounted for. In general, signals were local and required an explicit and well-powered reference framework for classification or tracking rehabilitation.