Impact of Flood on the Biodiversity of Agodi Gardens, Ibadan

Abstract

The study of flood effect on the species diversity in Agodi Biological Gardens was carried out to determine the rate of devastation that the catastrophes of 30 August 2011 flood disaster caused on the ex-situ environment. Both physicochemical parameters and structured questionnaire were used to assess the rate of devastation effect for a period of five months after the flood occurrence. Water analysis was carried out for heavy metals and trace elements, while questionnaire was administered to both staff and visitors for their perception. The results revealed that there was no effect of heavy metals from the sampled water, while the trace elements tested showed greater values in Manganese (6.81) and Iron (5.5), which are much higher than the standard values. Some species of animals (Tortoise Gopherus polyphemus (1), Parrot (Psittacines) (2), Ostrich- Strutios carmelus (1), Water geese (3), Peacock (2) and Nile crocodile (1) were decimated or carried away by the flood during and after the incidence. During the 1980 flood, all the fauna species were reportedly swept or carried away. The Garden is densely forested mostly by abundant species: Gmelina aborea (10.32859 relative density) and Tectona grandis (23.0046 relative density), which were adversely affected by incidence of flood (6 and 20 tree uprooted respectively). Twenty eight standing trees were uprooted or fell down either on the animals’ cages or obstructed the visitors’ parts. Most of the respondents (68.4%) to the Garden claimed that they were aware of the flood’s effect on the species (flora and animals), while 80.8% showed great displeasure and all the staff had negative perception of the devastating effect of flood on the species survival. From the aforementioned results, it has been observed that floods have had a serious inhibitory role on Agodi Biological Garden over the years. Such inimical effect of floods must be checked or controlled if this ex-situ centre will continue to survive to play a key role for the conservation of biological diversities.

Keywords: Species diversity, Flood effect, Agodi Biological Garden, Climate change.