Effects of Vegetation Loss on Cross River Gorilla (Gorilla gorilla diehli) in Cross River National Park, Cross River State, Nigeria

Abstract

This research looked at the effects of habitat loss on Cross River gorilla (Gorilla gorilla diehli) in Cross River National Park, Cross River State, Nigeria. The study quantified vegetation loss in the study location over a period of thirty five (35) years, and also Assess tree species abundance and distribution in the study areas. The research make known the concept of habitat loss, major kinds of habitat loss, main causes of habitat loss, and effects of habitat loss and fragmentation on biodiversity conservation, effects of habitat loss and fragmentation on primates, effects of deforestation, given a detailed description of the study areas, vegetation of the park, drainage pattern of the park, stating the method of data collection. To quantify the vegetation loss in the study areas, normalized difference vegetation index (NDVI) was used. Three (3) multi-date Landsat satellite imageries, Thematic Mapper (TM+) of 1991, Enhanced Thematic Mapper (ETM+) 2000 and Operational Land Imager (OLI) of 2021 were employed. The data was Analyzed using descriptive statistical tools such as bar charts, pie charts and pictograms, base on the categories of the DBH (diameter at breast height) obtained, and landsat imagery of the areas was obtained from 1990-2025. The comparative findings on tree species diversity, distribution, abundance, and important value index in the study areas showed significant differences in various ecological metrics between the two ranges (Okwango and Anape). The Okwango range had 1,078 individual trees, marginally more than the Anape range, which had 1,065 individuals in its sample. The study concludes that forest and vegetation cover showed a steady decline throughout the period. The net reduction of nearly 37,500 hectares indicates the adverse impact of anthropogenic activities such as deforestation, agricultural expansion, and urban sprawl. And recommended that, land surveys should be carried out to determine the rate of encroachment into the Park by loggers and farmers, and efforts should be made to adequately protect the study area, since it is one of the few location in the country where some valuable tropical and indigenous trees species can be found.