Mammoths were widely around until 10,000 years ago, with some surviving until as recently as 4,000 years ago. Mammoths are thus not particularly 'alien' organisms from a modern ecological standpoint. They lived and evolved alongside much of the modern flora and fauna, including humans who are, incidentally, likely responsible for their extinction. It is therefore highly unlikely that the introduction of a mammoth population would severely perturb natural ecosystems. In any case, the extent to which there really is a "benevolent balance of nature" has been vigorously contested in biology. Food weds are often maintained despite significant fluctuations in extinction, invasion, migration, diversity, and energy pathways.