Soil seed bank profile of a frequently mowed lawn in Nnamdi Azikiwe University, Awka, Nigeria

Abstract

Seed bank study of a frequently mowed lawn at the Nnamdi Azikiwe University, Awka, Nigeria was undertaken between August 2015 and March 2017 to compare the soil seed bank with above-ground vegetation and the relationship between both. Soil samples were randomly taken from four points in a sampled area of 100 m2 at depths of 0-5 cm, 5-10 cm and 10-15 cm. Species were identified by using manuals, on-line identification kits as well as by some ecologists. Results showed that Imperata cylindrica was dominant; in the seed bank at 0-5 cm, an unknown species A (Asteraceae) was dominant; Oldenlandia corymbosa was observed at depths of 5-10 cm and 10-15 cm. The Shannon-Wiener index for the above-ground species was summed at 39, H1 (2.22), Hmax (3.03) and Equitability ratio (0.72). Sorensen’s coefficient was 0.037. Six species occurred in the above-ground and seed bank. The study concludes that original species in the seed bank could have been replaced by new species such as Imperata cylindrica and Commelina species due, perhaps, to succession and extinction. It is recommended that restoration of the pioneer species should commence with the propagation of seed bank species and that mowing should only be allowed at pre-bloom stage.