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
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