Abstract. Islands house a majority of the world's biodiversity and are thus critical for biodiversity conservation. Seabird nesting colonies provide nutrients that are integral to maintain island biodiversity and ecosystem function. Invasive rats destroy seabird colonies and thus the island ecosystems that depend on seabird-derived nutrients. After rat eradication, it is unclear how long ecosystem recovery may take, although some speculate on the order of centuries. I looked at ecosystem recovery along a chronosequence of islands that had 12-22 years to recover following rat eradication. I show that soil, plant, and spider marine-derived nitrogen levels and C:N ratios take mere decades to recover even after centuries-long rat invasion. Moreover, active seabird restoration could speed recovery even further, giving much hope to quickly conserve many endemic species on islands worldwide.

The note is concerned with estimates of the accuracy of the one-term formula for the energy dependence of the reaction cross section for charged particles. The second term in an expansion of the cross section in powers of the energy is worked out for a one-body model. Comparison with data of Sawyer and Phillips on the bombardment of Li and Be with protons and deuterons shows that the deviations from the one-term formula are of the correct order of magnitude to be accounted for by the second term. This term was compared with the effect of the 107-kev resonance on the cross section of H 3 (<#,n)He 4 . Employing a conservative centralfield model the correction term to the one-body asymptotic form is found to be smaller than the effect of the resonance expected from the Breit-Wigner formula. The/-function generalization to L>0 which has been made by Breit is studied and a table facilitating its use for the calculation of reaction cross sections is given.

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