Whatever the mechanism, though, this study provides what no previous study ever has: evidence from a controlled experiment that keystonespecies really exist.
Like the humble starfish that preserves entire marine ecosystems by eating mussels, the American public library is the keystonespecies in the ecosystem of reading.
Mistletoe is thus acting as what ecologists refer to as a keystonespecies: it supports an entire ecosystem, and removing it has drastic effects for the whole.
We need to illuminate the types of responses by individual organisms elicited by different noises, likely focusing mostly on keystone, indicator, and species already identified as endangered.