We just uploaded a preprint on the generality of the island rule. This rule has been supported & rejected by several authors since it was first postulated in 1964 by Foster. Here we revisited the rule using a global dataset of ~2000 island-mainland comparisons for ~800 species. https://twitter.com/biorxiv_ecology/status/1266007112339030016

To test the rule, we regressed the ratio between the mean an insular body size and the (ancestral) mainland body size, against the body mass of mainland populations. A positive intercept and negative slope would provide broad-scale support for the island rule.

We show that ‘island rule’ effects are widespread in mammals, birds and reptiles, but less evident in amphibians, which mostly tend towards gigantism

We also found that the magnitude of insular dwarfism and gigantism is mediated by island size and isolation, particularly in mammals and reptiles. In short, insular size shifts are exacerbated in remote, isolated islands.

I have enjoyed a lot working on this paper, which is somewhat different to my previous research line. Expect more of this stuff in the future! A big shout out to my great collaborators @L_Santini_Eco, @JuanGallegoZ, @ja_tobias, @borjamila, Patrick Walkden and Mark Huijbregts.