The Welfare Implications of Using Exotic Tortoises as Ecological Replacements

<div><h3>Background</h3><p>Ecological replacement involves the introduction of non-native species to habitats beyond their historical range, a factor identified as increasing the risk of failure for translocations. Yet the effectiveness and success of ecological replacement rely in part on the ability of translocatees to adapt, survive and potentially reproduce in a novel environment. We discuss the welfare aspects of translocating captive-reared non-native tortoises, <em>Aldabrachelys gigantea</em> and <em>Astrochelys radiata</em>, to two offshore Mauritian islands, and the costs and success of the projects to date.</p> <h3>Methodology/Principal Findings</h3><p>Because tortoises are long-lived, late-maturing reptiles, we assessed the progress of the translocation by monitoring the survival, health, growth, and breeding by the founders. Between 2000 and 2011, a total of 26 <em>A. gigantea</em> were introduced to Ile aux Aigrettes, and in 2007 twelve sexually immature <em>A. gigantea</em> and twelve male <em>A. radiata</em> were introduced to Round Island, Mauritius. Annual mortality rates were low, with most animals either maintaining or gaining weight. A minimum of 529 hatchlings were produced on Ile aux Aigrettes in 11 years; there was no potential for breeding on Round Island. Project costs were low. We attribute the success of these introductions to the tortoises’ generalist diet, habitat requirements, and innate behaviour.</p> <h3>Conclusions/Significance</h3><p>Feasibility analyses for ecological replacement and assisted colonisation projects should consider the candidate species’ welfare during translocation and in its recipient environment. Our study provides a useful model for how this should be done. In addition to serving as ecological replacements for extinct Mauritian tortoises, we found that releasing small numbers of captive-reared <em>A. gigantea</em> and <em>A. radiata</em> is cost-effective and successful in the short term. The ability to release small numbers of animals is a particularly important attribute for ecological replacement projects since it reduces the potential risk and controversy associated with introducing non-native species.</p> </div

A theoretical investigation of low energy proton on hydrogen collisions

The Proton on Hydrogen collision problem is treated in the time-dependent formalism using a new self-consistent nuclear trajectory model in conjunction with a simple semi-classical approximation. In this method the nuclear trajectory is dependent on the time-evolution of the electronic wavefunction which is described by a basis of H₂⁺ eigenfunctions. The small-energy, large scattering angle region is well described in this way and agreement with available experimental data is obtained. Tile inclusion of the semi-classical approximation and the use of a larger molecular basis than hitherto employed allow these limits to be quite reasonably extended to describe the small angle and moderate energy region also. Results of charge exchange probabilities and differential-scattering cross-sections in the range 150-1000 e.v. (lab. energy of incident proton beam) are presented along with some inelastic calculations on excitation into the Hydrogen 2p±1 and 2S states. It is further shown that the inclusion of the Gerarde states (2Sσg, 3Dσg) in the basis set has a significant effect on the results obtained for collision energies of 700 e.v. and 1Kev. A new numerical method is described which enables very rapid computation of all quantities required for the basis set, and leads to quick and simple integral calculations