This rodent is recorded in montane forest on Bioko Island. A 1973 monograph treated the island population under the then-subspecies name Hybomys univittatus basilii and described it as common in montane forest.
In the old classification, the Bioko form was darker above than mainland badius, with the black dorsal stripe greatly reduced or absent, no chamois tone below, and longer fur.
On Bioko, the account says it preferred montane forest, where it was very common and recorded up to 2,000 m. One lower-elevation record came from Bonyoma at about 450 m.
An extinction-risk assessment has not been added yet.