Importance of arbuscular mycorrhiza fungi in the restoration of a disturbed site in Kakamega forest

Abstract

Kakamega forest, a major reservoir of biodiversity in Kenya has experienced degradation over a long period of time due to human disturbance. This disturbance has resulted in a heterogeneous mixture of vegetation including disturbed primary forest, secondary forest, clearings and glades, and timber plantations. Restoration of the forest ecosystem has included the re-establishment of native tree species in order to accelerate recovery of the degraded areas and connect formally joined forest fragments. The degraded habitats, besides losing the above ground vegetation, have also lost the below-ground biological organisms. Often, restoration efforts have disregarded these below-ground organisms, some of which are crucial in maintaining plant community structure. It was hypothesised that the mycorrhizal abundance and diversity in soils of these degraded areas would affect plant growth and establishment rate in the restoration efforts. The study developed a vegetation map of a disturbed site within the Forest and assessed the mycorrhizal abundance and diversity in soils of the identified vegetation stands. Arbuscular mycorrhiza fungi abundance and diversity was found to be low at the disturbed site and also varied according to vegetation type and soil properties. The study also sought to determine the mycorrhizal dependancy of Erythrina abyssinica, Markhamia lutea, and Senna spectabilis seedlings which were some of the tree species identified for planting in the restoration efforts. The seedlings were found to be facultatively mycorrhizal but contamination of the experiment obscured the clear benefit of arbuscular mycorrhiza fungi colonization on seedling establishment.