This is what Dr Isobel Roberts and myself set out to investigate, with a team from the Australian Captial Territory Government.
Interestingly, we found very little response to rock addition, despite a region-wide, replicated restoration effort (12 tonnes of crushed bedrock) and an extensive functional analysis of invertebrate communities (29,164 individual invertebrates from 19 orders).
Rocks did not have a positive or negative effect in the short term (3 years) on invertebrate biodiversity.
There is little risk of negatively impacting invertebrates with rocks, while there might be positive benefits over the longer term, especially for other animals like lizards.
Roberts, I., Milner, R.N.C., Howland, B., Lumbers, J., Gilbert, M. & Smith, A.L. 2024. Effects of abiotic restoration through rock addition on invertebrate functional diversity in native temperate grasslands. Restoration Ecology, e14192.