Diversity of Ferns and Fern Allies Across Elevation and Aspect in Rukum, Nepal

Abstract

Fern and fern allies are the group of non-flowering vascular plants that are playing an important role in ecosystem structure and functioning. In this research we aimed to compare the diversity of ferns and their allies between northern and southern aspects along the elevational gradient of eastern Rukum, Nepal. Total 160 quadrats, each measuring 5 m × 5 m were laid using purposive sampling at each elevational band to cover all possible vegetation habitats. A total of 50 species of ferns and fern allies under 32 genera and 14 families were recorded. Species richness was recorded highest around 2000 m above sea level, indicating a mid-elevation diversity peak. The southern aspect of hill supported higher diversity with 41 species, compared to the northern aspect, which had 33 species. This diversity difference suggests that microclimatic variations between two aspects of hill. Similarly, species evenness was peaked at around 2200 m asl., while both species richness and evenness declined above 2300 m likely indicates the effects of extreme climatic conditions and reduced habitat suitability. These results therefore show the importance of this less explored mountain region for future botanical exploration.