COLLEMBOLA RICHNESS AND DIVERSITY ALONG A GRADIENT OF LAND-USE INTENSITY AND SOIL ABIOTIC FACTORS 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) vegetable fields. The eight land use types include stands of Pinus patula (LUT 1), Cypress lusitanica (LUT 2), Indigenous forest (LUT 3), Fallow (LUT 4), Pennisetum purpureum (LUT 5), horticulture fields (LUT 6), Coffea arabica (LUT 7) and Zea mays intercropped with Phaseolus vulgaris (LUT 8). The dynamic behavioural modified Berlesse funnel technique was used for collembolan extraction from soil and identified to genus level. A total of 6665 individuals were identified from 30 genera. Generally, low Collembolan population were recorded in the wet season of 2007 with total of 1973 individuals compared to 8638 individuals in the dry season of 2008 sampled in all the land use types (LUUs). The highest Collembolan population was recorded in LUT 2 (2827) and lowest in LUT 8 (148). 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 LUT 1, LUT 2 and LUT 5 had high carbon, nitrogen and acidity, supported high numbers and diverse Collembolan assemblages. The results show that both abundance and diversity of the soil Collembolan communities were better in the undisturbed sites than in the disturbed land use types. In conclusion the Collembolan communities are negatively impacted by land use intensity.