Ecological impacts of fragmentation on the diversity and distributions of indigenous tree species in tropical rainforest of Nigeria

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Research Paper 03/10/2022
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Ecological impacts of fragmentation on the diversity and distributions of indigenous tree species in tropical rainforest of Nigeria

Ndakara Ofudjaye Emmanuel, Atuma, Ifeanyi Morrison, Iwegbue Chukwujindu Maxwell Azubuike
J. Bio. Env. Sci.21( 4), 22-34, October 2022.
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This study investigated the ecological impacts of fragmentation on diversity and distributions of indigenous tree species in Nigerian rainforest, with the aim to ascertain how fragmentation impacted on the species of Ceiba pentandra, Irvingia gaboneensis, Piptadeniastrum africanum, Milicia excelsa, Musanga cecropioides, and Pentaklepta macrophylla. The study was carried out in 42 randomly selected matured rainforest fragments above 80 years within the 7 States of the Niger Delta region (grouped into 21 small and big fragments respectively). Data collected were on fragments sizes and tree species populations, through quadrats of 10m × 10m. Statistical analysis of data involved the descriptive, regression, t-test, similarity and diversity indices. Results showed that population of trees, population density and species populations differed among the fragments and significantly varied between the small and big fragments groups. Population densities were higher in big fragments. Populations of trees were significantly related with fragments sizes, with correlation values of 0.90 and 0.79 for the small and big fragments. High similarity index of 91% for the tree species was observed between the small and big fragments. With calculated t-value of 0.265 < table t-value of 2.228, the diversity index between small and big fragments was not significant at 5% level of confidence. Species diversity was higher in small fragments. Fragmentation had higher impact on species richness than their relative abundance. In conclusion, fragmentation has impact on diversity and distributions of tree species. Ecosystem-based management is recommended as an approach to ensure sustainability of indigenous tree species in the rainforest, for the purpose of biodiversity conservation.


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