Assessment of the Impact of Land-Use Change on the Abundance, Composition and Diversity of Mangrove Insects in Bundu-Ama, Niger Delta

Abstract

Mangrove insect abundance, richness and diversity are currently experiencing a huge decline due to human activities especially in developing nations. In this study, we set out to assess the impact of land use change on the abundance, composition and diversity of mangrove insects in Bundu-Ama, Niger Delta, between the year 2017 and 2023. For this to be achieved, sampling exercise was conducted every other week for a period of three months. Insects were collected and documented with reference to the particular tree species where it was foraging at the point of collection. Insect identification was conducted in the field and later verified in the lab. A Geographic information systems software was used to determine the change in mangrove vegetation between both study periods. The result showed that about 3.39Ha of mangrove in the immediate surroundings of the sample site have been lost to infrastructure development during the period. This also resulted in a huge decline in the insect biodiversity of the mangrove ecosystem. In Avicennia, the insect population reduced from twenty-two to nine insect species, twenty-one to nine insect families, with a shift in dominance from Formicidae to Tabanidae. More so, diversity reduced to 1.766, evenness reduced to 80% and a dissimilarity value of 58% was recorded during the period. Meanwhile in Rhizophora, the insect community reduced from seven to three insect species; the family also reduced from seven to three, with Formicidae retaining its dominance. The ecological indices showed that diversity was very low (0.874), evenness increased slightly to 80% and the dissimilarity index was 41%. The study asserts that consequence of the loss of insect communities in the area would result in the decline in ecosystem services such as food provision, diseases control, loss of gene pool, plus an alteration in the natural, biological and environmental cycles. Hence, there is an urgent need for action from stakeholder groups to halt this menace and rehabilitate the mangrove ecosystem halting the detrimental impact on insect biodiversity. Moreover, there is an imminent need to educate the citizens on the consequences of their activities on the environment.

Keywords: Mangrove, Insect, Land use, Niger Delta, Biodiversity

DOI: 10.7176/JEES/14-4-01

Publication date: June 30th 2024