ASPECTS OF HOLOCENE VEGETATION RECONSTRUCTION OF SOUTH EASTERN NIGERIA POLLEN RECORD FROM OZZI LAKE, OPI, NSUKKA, ENUGU STATE
A palynological study of the Palaeo-vegetation of Opi Nsukka, north eastern Enugu State was investigation through a palyno-analysis of 1.5 m lake sediment core collected from Ozzi Lake, Ugwu Ozioko Opi- Agu Nsukka Enugu State. The pollen flora showed that a total of 52 pollen types belonging to 30 families were recorded. Fungal and fern spores in addition to charred plant particles were also recorded from the sediment profile. The pollen diagram was divided into four zones based on the pollen curves which suggest possible changes in vegetation. The pollen profile provided evidence of a southern guinea savannah in the late Holocene. Prior to about 3800 ± 30 BP and mid part of zone iv, there was paucity of both the lowland rainforest and savannah elements in the vegetation, but with a relative increase in grass. Also the decrgease in the members of aquatic species and hydrophytic plants indicate that the period must have been drier than humid. This can also be substantiated by the rise in the peaks of Poaceae curve. Prior to 1910 ± 25 BP to about 340 ± 25 BP, there were subtle floristic changes in the vegetation from that of closed forest-savannah vegetation to an open vegetation. This is attributed to successional changes between the lowland rainforest and the savannah species due to alternating fluctuations between the dry and humid conditions. The paucity of pollen of both the savannah and the lowland rainforest species at the later part of 340 ± 25 BP is attributed highly to increase in anthropogenic activities.