Hypothesis
Because one generalist species (Gould's wattled bat) dominates bat-box use, installing boxes would shift local bat communities towards lower diversity.
What failed
A five-year before-after control-impact experiment at 18 sites in south-eastern Australia, using 9,035 bat-detector nights, found little difference in community composition, diversity or species activity between sites with existing boxes, newly added boxes or no boxes.
Broken assumption
Who uses an artificial roost dictates the composition of the surrounding bat community.
Why
The generalist kept dominating the boxes themselves, but that did not translate into a community-level change over the short-to-medium term studied.
From the published paper: Griffiths et al. Scientific Reports, 2020. ↗CC BY