The composition and distribution of vascular epiphytes along altitudinal gradient in Gashaka Gumti National Park, Nigeria

Abstract

A survey of epiphytes at four different altitudes in Gashaka Gumti National Park was carried out. A total of forty one species of epiphytes distributed in fifteen families were recorded from the four sites sampled. Fourteen species of epiphytes were recorded from the two lowland sites (<1000m, asl) and twenty eight samples were recorded from the two highland sites (1800-2410m asl). The epiphytic flora is dominated by the Family Orchidaceae with seventeen species. The number of epiphytes increased with altitude up to a point (1800m asl) and declined at higher altitude due to a drier and cooler environment, combined with less developed vegetation structure. Some epiphytes such as Calyptrochilum spp , Platycerium spp., Nephrolepis biserrata and Aerangis biloba were restricted to lowlands so they are called lowland epiphytes while those restricted to higher altitudes such as Angraecopsis sp., Asplenium spp, Lycopodium brachystachys and Vittaria guineensis are called highland epiphytes. The montane forests at mid altitudes (1800-2000m, asl) were dominated by pteridophytes because the environment was cooler, more moist and the canopy provided shaded habitats.

Keywords: epiphytes, GGNP, montane, pteridophytes, orchids