Impact of Land Use on Arbuscular Mycorrhizal Fungal Communities in Machinga District, Southern Malawi.

The influence of land use on soil bio-resources in Sub-Saharan Africa is largely unknown. With ever increasing pressure on natural resource base, the trend of converting natural forests to croplands is only expected to increase. Natural forests in sub-Saharan Africa harbor a rich source of biota which include arbuscular mycorrhizal fungi (AMF). Yet, very little is known about the effects of conversion changes on AMF in the region. We examined communities of AMF in Miombo woodlands (natural forest) and croplands located within Malosa Forest Reserve in Machinga District, in Malawi, a country in sub-Saharan Africa. Three smallholder plots under continuous monoculture maize, three plots under maize – pigeon pea intercrop and 3 natural forest sites lying in close proximity to the croplands were included in the study. Results revealed significant variation in AMF fungal community species composition among land use types. Shannon-Weiner diversity index differed significantly (F_2,24 = 22.24, p<0.0001)  among land uses with significantly higher H´ in agricultural soils than in natural forest soils. Contrary to ecological predictions, we found no evidence of a negative effect of crop production on the taxonomic diversity of AMF. However, our study showed a significant negative influence of agricultural intensification on AMF spore abundance and AMF community structure. Further research should investigate if AMF assemblages identified vary in their functional traits and their implications to ecosystem function or agronomic performance.