Eradicating invasive mammals did not quickly restore the nutrient pathway seabirds once supplied
WHAT THE EVIDENCE SAYS
Using 408 contemporary and historical specimens spanning 169 years, researchers compared Rangitāhua with nearby mammal-free Meyer Islands. Dense seabird colonies on the Meyer Islands were associated with stronger marine-derived nutrient signatures, higher soil phosphorus and lower pH. On Rangitāhua, seabird recovery remained slow more than two decades after predatory-mammal eradication, and terrestrial and nearshore isotope patterns did not simply return to the seabird-driven reference condition.
WHY IT MATTERS / OUR READ
Removing the original pressure can be only the first step in ecological recovery. When a lost species once moved nutrients across ecosystem boundaries, restoration may need to consider the return of that ecological function—not just the absence of the invader that disrupted it.
CAVEATS / UNCERTAINTY
The islands are not perfect historical analogues, and stable-isotope trajectories can be affected by volcanic activity, sampling differences and other environmental change. The study does not show that active seabird translocation is always required; it shows that functional recovery can lag eradication and deserves direct measurement.
SOURCE
Ecosphere
View original evidence ↗
A 169-year isotope record from Rangitāhua and nearby mammal-free Meyer Islands suggests ecosystem function can lag predator eradication by decades.
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