H. brevicula is very rare—only ten specimens have ever been collected—and critically endangered: the species was found only in Eyrewell Forest, a single plantation of exotic pine trees currently being converted into dairy farms.

H. brevicula can be distinguished from its slightly larger close relative H. algida by the patterns of punctures and setae on its pronotum and elytra, and by the male's shorter aedeagus.

Some of the older blocks had an understory of kānuka up to 4 m high and most included native shrubs, herbs, and mosses, despite regular tree felling and replanting.

At the same time it has disappeared from the remaining fragments of nearby kānuka forest, which appear to be too small, increasingly degraded, and browsed by sheep to support populations of the beetle.

[11] The beetle has no legal protection under the Wildlife Act, and in New Zealand plantation forests on private land can be felled, even if they are the only habitat of a threatened species.

[18] The conversion involved "felling all the trees, ripping out the root stock and then pretty much mulching the coarser woody material which is left behind into small chips… not only shredding any plant matter, but any invertebrates that are larger than a pinhead.

"[17] Correspondence obtained under the Official Information Act revealed that the Department of Conservation had been unable to reach an agreement with Ngāi Tahu Farming over preserving enough beetle habitat to save the species.

[17] Scientists criticised the decision to convert the forest to dairy farms as "driven by an economic assessment of profitability, with little consideration of biodiversity values.