Diversity of Epiphytic Lichens in Urban, Peri-Urban and Adjoining Rural Areas of Benin City to Monitor the Ecosystem Health

Abstract

Lichens are widely used as biomonitors of environmental pollution, few lichen studies have been used to assess environmental quality in Nigeria. Managed and natural areas within Benin City metropolis and adjourning areas were investigated using lichen diversity to determine the ecosystem health status in four sites: Urban, Peri-urban, Rural and the Reference site. Lichen colonies obtained in triplicates per site from 10 mature trees (>60cm ghb) were collected and identified using standard keys and manuals. Based on the European Guideline procedure, Lichen Diversity Value (LDV) were estimated from lichen colony count obtained from a ladder grid (10cm x 10cm) at five levels placed perpendicularly at four aspects (North, South, East west) on each side of the tree at 100cm above ground level. Site disturbance statuses were deduced from the LDV position on the percentage environmental alteration scale. Growth form distribution were crustose 12 (85.71%) and foliose two (14.29%). Six lichen taxa was identified to generic levels. The estimated LDV which inferred environmental alterations for each site were: Urban (13.60), Rural (16.30), Peri-urban (19.70) and Reference site (33.77). These findings show high environmental alterations (stress) in the Urban and Rural areas with the reference site moderately altered with less external stress.