Assessment of soil seed banks in relation to aboveground vegetation in three ecosystems within university of ibadan, Ibadan, South Western Nigeria

Abstract

Succession after disturbance. In the assessment of natural re-vegetation capacity of some ecosystems within the University of Ibadan, Nigeria, SSB contents were assessed and compared with the above-ground vegetation (AGV). Three ecosystems (Arable, Fallow and Plantation) were selected, with 25 x 25 m area marked out in each for random sampling, using XY-ordinate technique. Ten points were located for placement of wooden quadrat (50 x 50 cm). All plant species that rooted within each quadrat were enumerated. Soil samples were collected at 0-15 cm depth at the centre of each quadrat and bulked by site. One kilogram soil, replicated 12 times in each site, was monitored for seedling emergence for five months. Species richness (R), Shannon-Wiener index (H') and Jaccard Similarity Index (J) were determined for AGV and SSB. Plant family Poaceae dominated AGV while Amaranthaceae dominated SSB in all ecosystems. The R in AGV and SSB ranged from 14-24 and 6-15 respectively. The H' in AGV were close (2.27-2.69) but ranged from 0.84 (plantation) to 2.27 (arable) in SSB. The J for SSB/AGV were 33.3%, 14.3% and 5.9% in arable, fallow and plantation ecosystem respectively, indicating the highest species resemblance in the most disturbed arable ecosystem.