Crocidura allex is a montane species found in alpine grassland and swamp areas, including above the treeline. On Mt Kenya it has been recorded on the Chogoria slope up to 3,600m asl within areas of Juniperus–Hagenia habitat, with canopy dominated by Hagenia abyssinica and large patches of tussock grasslands, as well as alpine moorland habitat dominated by Erica and Stoebe. On the same mountain it is absent on the Sirimon slope within the same elevational range, where Dendrosenesciois is more common (Musila et al. 2019). Animals were collected around buildings at Saddle Hut, Mt. Meru, but not in the surrounding forested habitats, leading Stanley and Kihaule (2016) to suggest that they were there having been introduced by human activities, or are supported by habitat alteration associated with the dwellings. Little additional information is available on the natural history of this species.

This species occurs in protected areas on Kilimanjaro, Meru, as well as mountainous areas of Aberdare National Park, Mt. Kenya National Park, and the Mau Escarpment. Further studies are needed into the distribution, abundance, breeding biology and general ecology of this species. Further information is also required on the status of its habitat to monitor the potential impacts of climate change.