Hypothesis
Eradicating dingoes from fenced areas would release red foxes, feral cats and goannas from suppression, so their numbers would rise.
What failed
Dingoes were removed and kept at undetectable levels for 4–5 years in two fenced sites that blocked immigration, yet relative abundances of foxes, cats and goannas stayed low and stable throughout. Negative relationships between predator species were largely absent.
Broken assumption
Top predators hold smaller predators down at the population level, so removing them releases the smaller ones.
Why
The authors conclude that the suppressive interaction the theory relies on was not operating at the population level here; negative interactions between predators at small scales do not necessarily scale up.
From the published paper: Castle et al. Scientific Reports, 2021. ↗CC BY