Effects of environmental variables on the distribution and diversity of avian species in three selected locations in the University of Ibadan, Ibadan, Nigeria

Abstract

The effects of environmental variables on the distribution and abundance of avian species in the University of Ibadan was carried out.  Three sites were selected within UI [Fallow/Urban Land (FUL), Conserved Forest (CF), and Oil Palm Plantation (OPP)]. Birds were sampled  between November 2023 and March 2024 using the Point Count method with a 50m radius. Binoculars were used for visible species and a  voice recorder for audible but out-of-sight birds. Avian species composition and abundance were determined using standard methods.  Diversity was determined using ShannonWeiner index. Monthly temperature and rainfall data were collected from Nigerian  Meteorological Agency (NiMet). Data were analysed using descriptive statistics, Canonical Correspondence analysis, and Bray-Curtis  Cluster analysis in Paleontological Statistics (PAST). A total of 1,642 individual avian species were encountered belonging to 17 families.  The families Corvidae and Columbidae were the most dominant families in the study area. The highest and lowest diversity indices were:  FUL (2.271) and OPP (1.935) respectively. Temperature and rainfall ranges were 28.6°-32°C and 0-96mm respectively. Temperature  influenced the abundance of Spilopelia senegalensis, Crinifer piscator, Milvus migrans, and Columba sp. While rainfall influenced the  abundance of Bubulcus ibis. Both CF and FUL were similar in terms of avian diversity. Avian species were encountered in the University of Ibadan at low diversity. Hence, conservation efforts should focus on preserving diverse habitats and minimizing human impacts to  maintain healthy bird populations.