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The Andes of Colombia and Ecuador as a barrier to fern and lycophyte species from Mesoamerica

Morris, Sarah1; Moran, Robbin2

Published Jan 09, 2025 on Dryad. https://doi.org/10.5061/dryad.79cnp5j3v

Data files

Jan 09, 2025 version files 1.17 MB

Abstract

We compiled a list of the fern and lycophyte species that occur in Mesoamerica and extend into Colombia and Ecuador where they are restricted to the western side of the Andes; that is, they only occur west of the crest of the easternmost cordillera and are absent from that cordillera’s eastern slope and in adjacent Amazonia. We found 130 species with this Mesoamerican and west-of-the-eastern-cordillera distribution. Those 130 species constitute 7% of the total 1805 fern and lycophyte species that have been recorded west of the crest of the easternmost cordillera in Colombia and Ecuador. All 130 species had elevation ranges with midpoints lying in low (0–900 m) or middle (900–3000 m) elevations, and none were above 3000 m. This suggests the cordilleras have acted as elevational barriers. We also investigated the blockage of these 130 species by each of the Andean cordilleras. We found that 74 (57%) of the 130 species were limited eastward by the western cordillera, 15 (11%) by the central cordillera (this cordillera in Colombia only), and 41 (32%) by the eastern cordillera. If estimates of endemics to the western Andean region are considered, then at least 20–22% of all fern and lycophyte species are restricted west of the crest of the easternmost cordillera. Although usually exhibiting larger geographic distributions compared to angiosperms, fern and lycophyte species may show significant geographic restriction by mountain ranges.