Britannica Sources used in this answer

Why are ferns most diverse in tropical rainforests?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

tree fern — Fern Tree fern (*Cyathea medullaris*).

Ferns are most diverse in tropical rainforests primarily because these environments provide the warm, damp conditions that are essential for their growth and reproduction.12

The high humidity and consistent moisture found in tropical rainforests are particularly critical for the fern gametophyte, which requires a humid atmosphere and shaded, moist microenvironments to develop. Furthermore, the structural complexity of these forests allows for a wide variety of niches; in the tropics, as many as two-thirds of the ferns in a given area may grow as epiphytes on the trunks and branches of trees, effectively utilizing the vertical space of the forest.13

While ferns are found globally, their abundance and diversity diminish significantly with increasing latitude and decreasing moisture. The tropical rainforest acts as an optimal habitat where these plants can thrive, with some areas hosting over 100 species within just a few hectares.23