Abstract

Cryptogamic pteridophytes are primitive group of ferns sensitive to environmental disturbance; they serve as indicators and monitoring agent to the environment. This study was aimed at assessing their distribution using GIS techniques in parts of swamp vegetation of Forestry Research Institute of Nigeria (FRIN); with the objective of establishing the spatial distribution of the different species within the ecological study area. Three plantations (Allanblackia plantation, mixed plantation, and Irvingia plantation) of the swamp vegetation of the Forestry Research Institute of Nigeria, Onne were assessed. Sampled points of individual species were georeferenced using hand-held Geographic Positioning System (GPS). Result has recorded nine species (Marattia fraxinea, Nephrolepis pumicicola, Nephrolepis bisserata, Platycerium bifurcatum, Platycerium grande, Ophioglossum gomezianum, Pteris catoptera, Pteris acanthonuera and Selaginella myosurus) of Pteridophytes identified from the plantations. However, there were variation in distribution of species among the plantations and between species within plantation in their various georeferenced situate with Pteris catoptera and Selaginella myosurus the most abundant species. The Average Nearest Neighbor Analysis revealed a Nearest Neighbor Ratio of 7.91 greater than 1, implying a dispersion distribution pattern with a critical value (85.68) less than 1%. The distance analysis between species within plantation revealed in the Irvingia plantation a ratio index of 0.79 less than 1, implying a clustering distribution pattern with a critical value (-2.10) less than 5%. It is therefore significantly easier using Geographical Information System to know the widespread of ferns, their richness and diversity with respect to different habitat, and distribution rate in the study area.  

Key Words: Pteridophytes, Arboreal, Terrestrial, Eleme, Onne