Extra-Eureopean record in GBIF from USA is excluded.

Rare species occuring in endangered habitat.

The species is an indicator of old, extensively managed semi-natural grasslands in Europe. It is currently reported from 19 countries in Europe. GBIF database (GBIF 2019) contains more than 400 occurrences of this species in Europe.

Hygrocybe calciphila occurs in unimproved, semi-natural grasslands, in road verges, open woodlands, and deciduous scrublands. It is always found on calcareous or basic soils (Boertmann 2010), from lowlands up to 2300 m alt. in the Pyrenees. Suitable grassland habitats are those traditionally managed by grazing (by cattle, horses, sheep, deer) and/or regular mowing. It is important to sustain management practices that maintain the low levels of available nitrogen and phosphorus in the soil favorable for the existence of many rare and threatened fungal species associated with semi-natural grasslands.
Hygrocybe species were mostly regarded as saprotrophic in the past. Recently, Halbwachs et al. (2018) made an analysis of stable isotopes in their fruitbodies and suggested that Hygrocybe s. l. species are either endophytes or possibly form mycorrhizal relationships with plants.

Hygrocybe calciphila is threatened by fragmentation, degradation, and loss of semi-natural grasslands in Europe.