Diversity and Distribution of Pteridophytes in the Montane Ecosystems of the Nilgiris, Western Ghats

Abstract

The Nilgiris, located in the Western Ghats of Tamil Nadu, represent one of the most ecologically significant montane ecosystems in southern India. This study presents a comprehensive and systematic enumeration of ferns and fern allies (pteridophytes) inhabiting the montane forests, grasslands, and shola ecosystems of the Nilgiris. Field surveys were conducted across altitudinal gradients ranging from 1,000 to 2,600 meters above sea level to document species diversity, distribution patterns, habitat preferences, and ecological associations. A total of twenty (20) fern species, belonging to eight (08) genera and five (05) families, were identified, including several rare, endemic, and previously unreported taxa in this region. The findings reveal a high degree of species richness and habitat specificity, with the majority of species concentrated in moist, shaded ravines and shola forest understories. Taxonomic identification was carried out using morpho-anatomical features, supported by existing floristic literature and herbarium specimens. The population of ferns and their allies is rapidly declining due to factors like habitat degradation, anthropogenic impacts, climate change, etc., since they are highly vulnerable to changes in their native habitat. Since epiphytic species are often damaged by tree cutting, 41–43% of India's epiphytic pteridophytes are presently considered vulnerable. To ensure the diversity of species in a region, it is necessary to frequently analyze pteridophyte flora. The potential of in-vitro and ex-situ conservation techniques can be explored for the preservation of threatened pteridophyte species. The Present study provides a critical baseline for future conservation, ecological monitoring, and biogeographical studies of pteridophytes in the Nilgiri Biosphere Reserve.