Planktonic flora and fauna of Opa Reservoir wetlands, Obafemi Awolowo University, Ile-Ife, Nigeria

Victor Folorunso Olaleye,Henry Adefisayo Adewole,Emmanuel Olusegun Akindele,Aderonke Tolulope Adebayo

doi:10.1186/s41936-021-00237-8

Victor Folorunso Olaleye, Henry Adefisayo Adewole + Show 2 more

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https://doi.org/10.1186/s41936-021-00237-8

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Abstract

BackgroundWetlands are transition zones between aquatic and terrestrial environments of Opa Reservoir Obafemi Awolowo University, Ile-Ife, Nigeria, threatened by increase in agricultural practices and urbanization within the catchment area. A critical appraisal of the current ecological integrity of the wetlands using planktonic composition and community structure which are formidable to sustaining wetlands is essential, hence this study.ResultA total of 104 plankton species comprises of 68 species of phytoplankton and 36 species of zooplankton were recorded from the wetlands. In each sampled location and during the sampling period, Bacillariophyta had the highest occurrence among the phytoplankton, while Rotifera recorded the highest occurrence among the zooplankton. Generally, Synedra ulna and copepod (cyclopoid) Nauplius, respectively, were the most common phytoplankton and zooplankton recorded during the period of study. Analyses also showed that the phytoplankton had a higher species occurrence and abundance (65.3% and 98.18%, respectively) than the zooplankton (34.6% and 1.82%, respectively). Diversity indices (Shannon–Wiener, Margalef, and Simpson) analyses of both plankton groups revealed that the wetlands were generally polluted.ConclusionThe study concluded that the ability of the wetlands to support and maintain a balanced adaptive community of plankton with species composition and diversity is being eroded due to anthropogenic activities in the wetland areas. This could have some ecological and socioeconomic implications considering the fact that they are intrinsically a part of the adjoining reservoir which provides many ecosystem services.

Highlights

Wetlands are transition zones between aquatic and terrestrial environments of Opa Reservoir Obafemi Awolowo University, Ile-Ife, Nigeria, threatened by increase in agricultural practices and urbanization within the catchment area
Opa Reservoir was considerably rich in phytoplankton, and most of the recorded species have been previously reported in Nigeria and tropical freshwaters (Atobatele, 2013; Sharma et al, 2013; Singh et al, 2013; Peresin et al, 2014; and Akindele & Olutona, 2017)
It is worth being mentioned that the ratio of phytoplankton to zooplankton in terms of taxonomic composition (~ 2:1) and abundance (~ 6:1) in the wetlands suggests that phytoplankton is autotrophic and is at the base of the food pyramid in an aquatic ecosystem

Summary

Introduction

Wetlands are transition zones between aquatic and terrestrial environments of Opa Reservoir Obafemi Awolowo University, Ile-Ife, Nigeria, threatened by increase in agricultural practices and urbanization within the catchment area. Fen, peatland or water area, whether natural or artificial, permanent or temporary, with water that is stationary or flowing, which may be fresh, brackish, or salty, with a depth at low tide not exceed six meters, have provided a wide range of ecosystem services for humankind in all continents (Junk, 2002; Millennium Ecosystem Assessment, 2005) They are characterized by a large number of ecological niches and harbour a Adebayo et al JoBAZ (2021) 82:40 control, community structure and wild life support, recreation, and esthetics (Leck et al, 2012). The composition and community structure of plankton are useful in assessing the biological integrity and functioning of wetland ecosystem (Akindele & Adeniyi, 2013b; Brettum & Andersen, 2005)

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