Distribution and diversity of earthworm (Annelida, Clitellata)populations across four land use types in northern Cameroon

Earthworms are present in all types of soil. Changes in land use influence populations of earthworms. However, information on the dynamics of earthworm populations in northern Cameroon is not available. This paper highlights the research carried out on the abundance, biomass, and diversity of earthworm populations throughout four types of land use in northern Cameroon. Earthworms were sampled throughout the rainy season in three regions, across pastures, woody savannahs, grass savannahs, and fields, using formaldehyde and hand sorting. Earthworms of the woody savannah and pasture have a high mean density (63 and 45 individuals/m2, respectively) and biomass (25.2 and 22 g/m2, respectively). Region rather than land use had a significant effect (P = 0.031) on earthworm diversity. The increase in earthworm abundance in woody savannah and pasture is certainly due to the modification of the soil microclimate and litter by ligneous plants, and to the input of cow dung in pastures, both of which improve the quality and quantity of the organic matter brought to the soil. This research provides insight into the patterns of earthworm populations in northern Cameroon and the need to implement adequate use and management strategies for the maintenance of these soil organisms that provide major ecosystem services.