Abstract

Lantana camara L. (Verbenaceae) is an invasive shrub of global significance in the conservation of biodiversity in terrestrial ecosystems. The invasive species has profound impact on soil ecosystems due to its allelopathic and litter accumulation effect. This study tested for its impact on soil properties in Nairobi National Park (NNP) by randomly sampling soil from the invaded and un-invaded sites in three habitats namely forest, riverine and shrub-grassland using the Modified Whittaker plot design. Six plots were laid in the forest, four in the riverine and eight in the shrub-grassland. Ten samples were collected at invaded and ten at un-invaded sites per habitat totaling to sixty which were obtained and analysed. Two-way analysis of variance (ANOVA) results indicated significant differences in the values of soil pH, the concentrations of magnesium, calcium and potassium between the invaded and un-invaded sites and their levels were higher in invaded sites. Also magnesium, calcium and potassium varied significantly across the forest, riverine and shrub-grassland. These results suggest that L. camara can improve the nutrient levels of soil and therefore influence nutrient cycling resulting to making the ground better for its growth and this might explain the capacity of the invasive species to outcompete the native ones.

Key words: Biodiversity, conservation, impact, soil macronutrients, allelochemicals.