Collembola Richness and Diversity along A Land-Use Intensity Gradient in Taita, Kenya

Abstract

Soil Collembola communities were sampled along a gradient of land use intensification in Taita-Taveta, Wundanyi division, Coast Province during the wet season (October-November 2007) and dry season (February- March 2008). This gradient ranged from Natural undisturbed land use to intensively cultivated (disturbed) horticulture fields. The eight land use types (LUTs) were stands of (1) Pinus patula, (2) Cypress lusitanica, (3) Indigenous forest, (4) Fallow, (5) Pennisetum purpureum, (6) horticulture fields, (7) Coffea africana and (8) Zea mays intercropped with Phaseolus vulgaris. The dynamic behavioural modified Berlesse funnel technique was used for collembolan extraction from soil. Collembola were identified to genus level. 11462 individuals per m² were identified from 30 genera. Generally, low Collembolan population were recorded in the wet season of 2007 with density of 2618 individuals per m² compared to density of 8844 individuals per m² in the dry season of 2008 sampled in all the land use types (LUUs). The highest Collembolan population was recorded in Cypress lusitanica with a density of 3781 individuals per m² and lowest in Zea mays intercropped with Phaseolus vulgaris with a density of 198 individuals per m². A total of 30 genera in 11 families were recorded. The genus Cryptopygus was the most commonly sampled followed by Thalassaphorura, Parisotoma, Lepidocyrtus and Folsomides (37.2%, 17.7%, 8.5%, 6.1% and 5.5%) respectively. Land use type like Pinus patula, Cypress lusitanica, and Pennisetum purpureum had high carbon, nitrogen and acidity, supported high numbers and diverse Collembolan assemblages. The results show that both density and diversity of soil the Collembolan communities were higher in undisturbed sites than in disturbed land use types. In conclusion the Collembolan communities are negatively impacted by land use intensification.