Morphological Variation and Distribution of Earthworms in Soil Types of Ebonyi State, South East Nigeria

This study investigates the morphological variation and distribution of earthworm species across contrasting soil types in Ebonyi State, located in Nigeria's South East geopolitical zone. Earthworms are keystone decomposer organisms whose diversity and abundance profoundly influence soil fertility, structure, and biological activity, yet their ecology in Ebonyi State soils remains poorly characterised. Using a stratified sampling design, earthworms were hand-sorted from monolith samples (25 by 25 by 30 cm) at 30 sites across three soil types: red clayey soils, sandy loam alluvial soils, and degraded gully erosion soils. Samples were taken during wet and dry seasons at three Zoologyhs. Earthworms were identified morphologically to species and measured for length, width, and fresh weight. A total of six earthworm species were identified, with Lumbricus rubellus and Millsonia omodeoi being the most frequent. Sandy loam alluvial soils supported the highest species richness (five species) and biomass, while gully erosion soils were almost devoid of earthworms. Zoologyh distribution showed that 78 percent of earthworms were concentrated in the top 15 cm. Abundance was significantly correlated with organic carbon content, soil moisture, and pH. The study provides the first characterised earthworm species inventory for Ebonyi State and demonstrates the negative impact of soil degradation on earthworm communities. Conservation of surface organic matter layers through mulching and reduced tillage is recommended to sustain earthworm populations. Keywords: earthworms, morphological variation, soil types, Ebonyi State, soil biology.