ABSTRACT

A survey was conducted to determine the features and dominant soil, plant and macro-organisms that could serve as ecological indicators of some selected areas with different forms of land degradation across Imo and Abia states. The disturbed areas include an old gully erosion area, a 10 - year old kaolin mined area, a 3 - year old crude oil spilled/fire affected area and a 5 - year old cultivated farmland Ten meters away and 50m away from each ofthese areas served as moderately disturbed area and as control respectively. A 6 - 8 year old fallow land located 50m away from the cultivated farmland above served as control. Parameters determined are types of floral species and their population densities; soil physico-chemical characteristics and population of soil macro-organisms. Results show that the soil physico-chemical characteristics in each disturbed area were significantly different from that in the undisturbed areas. Major soil characteristics of gully erosion area are high P (23mg/kg) and low N (0.035%) while oil-spilled/fire affected area showed high Fe content (283.8mg/kg), low N (0 043%) and high OM (2.507%). Soils ofthe kaolin-mined area had low N (0.028%) and OM (0.586%) but high pH (4.41) and Fe (297.23mg/kg). Cultivated farmland had moderate N (0 140%), low Mg (0.4 cmol/kg) and low P (2.3mg/kg) while fallow land had N (0 196%) and high cations (CEC=5.665 cmol/kg) Soil macro-organisms were absent in the gully erosion area, oil-spilled/fire affected area as well as in the kaolin mined area. In the controls for the gully erosion area, Macrotermes Spp (arthropoda)was highest among other macro-organisms in the moderately disturbed area at 0 - 15cm and in the control (12.75/250g of soil) at 15-30cm soil depth. In the oil spilled/ fire affected area, Macrotermes Spp was also highest in the moderately disturbed area and in the control (0.75/250g of soil) at the 0 - 15cm soil depth. In the kaolin mined area, only Lumhricus Spp (annelida) occurred in the moderately disturbed area at 0 - 15cm soil depth. The cultivated farmland had only Lumhricus Spp (0.5/250g of soil) while its control (fallow land) contained high numbers of arthropods followed by annelida with representatives for each phylum at 0-15cm depth and 15-30cm depth. In terms of plant species, gully erosion area was characterized by Bamhusa vulgaris (Chamaephyte, Bamhuceae), oil-spilled/fire affected area by Oldenlandia herbacea (Therophyte, Rubiaceae)\ kaolin-mined area by PhyUtiithus amarus (Therophyte, Euphorbiaceaey, cultivated farmland by lower case herbs and grasses (e g. Pouzolzia giiineense'. Therophyte, Euphorbiaceae) while fallow land was characterized by diversity of floral members of different families. Lands undergoing various forms of degradation express different ecological characteristics as regards the soil chemical features, soil macro-organisms and vegetation; and these characteristics make useful input in rehabilitation process and subsequent usage