Abstract:
The study examined the impacts of urban greening induced species homogenisation on
ecosystem functions and services in some selected capital cities in the South south region of
Nigeria. The study established quadrats of 30mx200m along road (transects) in GRAs of Uyo
City, Akwa Ibom State and Yenagoa City, Bayelsa State labelled as sampled sites and a quadrat
of 100mx100m were established as control sites (secondary forest) at a minimum of 300m from
the sampled sites. Jaccard Similarity Index was used for the degree of homogenisation of plants
while Levene Statistics was used to determine the significant differences in the degree of plant
homogenisation between sample and control sites at p<0.05 significance levels. Findings showed
that Vossia cuspidata was highest (51.4%) in one of the sampled sites in Uyo City while
Cynodon dactylon highest (80.6%) in abundance in Yenagoa in one of the sampled roads.
Similarity index for homogenization was 1.6% and 10% in Uyo City and Yenagoa City
respectively. Furthermore, 96.8% of identified plants were missing in Uyo (GRA) sampled sites
(roads) while 84.6% of native plant species identified in the control sites are missing from the
urban sampled sites in Yenagoa City. The Levene statistics have shown that there is a significant
difference in the level of homogenization between sampled sites and control sites in the study
area (F=34.857; p<0.05). The plants in the control sites provided all ecological functions and
services more than the sampled site except ornamental functions (11.0%). The study concluded
that the introduction of non-native plants as a result of urban greening activities have altered
ecosystem functions and services and have promoted species homogenization in the urban
centres. Based on findings, the study recommended that urban greening projects and activities
should be managed effectively by the city authorities, to reduce its impacts on the plants species
diversity and to improve the vegetation status which can promote ecosystem functions and
services |
