In comparing rabbit population effects in New Zealand to potential effects in Iceland, one should keep three things in mind:
(1) Iceland has only about 40% as much land area as does New Zealand,
(2) Vegetation coverage in New Zealand is heavier and more diverse than it is in Iceland, and
(3) The number and diversity of animal species in New Zealand exceeds those in Iceland.
Each of these points suggests that a growing rabbit population would have a more rapidly evolving and more significant impact in Iceland than in New Zealand. Additionally, considering efforts to reforest Iceland, the rabbit population should be controlled. Feeding local groups of rabbits in may seem humane, but could lead to a population change that would have a lasting effect on Iceland.
Ed Smith, PhD
Center for Comparative and Evolutionary Biology of Hearing
University of Maryland