By: Adeboyejo A. A.; Onyekwelu J. C.; Oyerinde O. V.;
Abstract:
Akure Strict Nature Reserve (Akure SNR), Eda and Shasha forest reserves. Each forest was categorized into three forest canopy classes: open canopy, partial canopy cover and closed canopy. Overstory trees were inventoried in nine 625 m2 main temporary sample plots in each canopy class, resulting in 27 plots for each forest reserve. Sapling and seedling species were enumerated in 25 m2 and 4 m2 quadrants and sub-quadrants, respectively laid at the center of each main plot and quadrant. Results revealed that tree growth characteristics and most biodiversity indices decreased along canopy classes, with closed and open canopy covers having the highest and lowest values, respectively. Overstory tree species richness of the closed canopy (34, 29 and 26 at Akure SNR, Eda and Shasha forests, respectively) was significantly higher than that of open canopy (11, 16 and 18 in the respective forests). Similar trend was observed in the understories of the three canopy cover classes of the forests. Shannon-Wiener diversity index varied from 2.98 - 3.11 and 2.22 - 2.72 in closed and open canopy covers, respectively of the three forests while species evenness was similar in all the canopy cover classes. Stand basal area under the closed canopy (17.06 - 79.15 m2ha-1) was significantly higher than under partial canopy cover (9.32 - 23.48 m2ha-1) and open canopy (5.61 - 6.41 m2ha-1). Since the degree of canopy openness is linked to forest degradation, the poor growth and biodiversity indices of the open canopy class is attributed to anthropogenic disturbances, which pose great risk to forest growth and biodiversity conservation. It is recommended that anthropogenic activities in the forests be reduced or halted to prevent further degradation, promote conservation and regeneration. Restoration in the partial and open canopy portions of the forests is also recommended
Keywords: Biodiversity indices; canopy cover species; conservation; forest disturbance; forest reserve, Nigeria
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