Mycorrhizal Fungi and Reforestation in an Eastern Lowland Rainforest of Madagascar

Most terrestrial plants worldwide make associations with mycorrhizal fungi, yet the fungal diversity of Madagascar is vastly unknown. This research project is a preliminary investigation into the mycorrhizal status of 19 tree species in and near Ranomafana National Park (RNP), a lowland tropical forest on the southeast coast of Madagascar. Arbuscular mycorrhizal (AM) colonization in these species was studied in root samples under the microscope in the laboratory of Centre ValBio (CVB). The degree of AM infection was assessed for three study areas: one directly adjacent to a protected area and two reforestation sites supported by CVB. For the 19 samples examined, 16 (84%) were determined AM colonized to varying degrees. Three species were inconclusive and require further analysis. Results also suggested that the degree of AM infection was reduced at the reforestation sites, with only 9% of samples being heavily infected compared to 25% of samples adjacent to the protected area. Additionally, above-ground fruiting bodies (mushrooms) were photographed and some later identified to describe the ectomycorrhizal (ECM) fungi abundance in the study areas. These macroscopic observations simply suggested the presence of ECM associations with certain species, and mushrooms were much more abundance in the protected area of RNP. However, no real conclusions could be made about the ECM status of trees, and only a few fungal species could be confidently identified. To conclude, this study found that most native tropical trees in RNP make AM associations to varying degrees, including the more abundant species. Land degradation from previous cultivation may influence mycorrhizal abundance as well, though more research is necessary