Arbuscular mycorrhizal fungal dynamics following change of land use from mature forest to Eucalyptus plantation

Change of arbuscular mycorrhizal fungi (AMF) dynamics following land use change was investigated. A study was carried out using four land use types viz., a mature forest (MF), a Eucalyptus plantation (EP: which was established after clearing mature forests in the area in 1980s) and two regenerating forests (Re: following clear-cut of Eucalyptus in 2005), where one is bordered by a Eucalyptus plantation (Re-EP) and the other bordered by a mature forest (Re-MF), located in the Intermediate Zone of Sri Lanka. Soil samples were collected from each land use type and the AMF spores were quantified and identified into morphotypes. Percentage AMF colonisation in fine roots was also quantified. Some basic soil parameters (pH, soil moisture, available P and total C) were also tested. A total of 24,698; 16,379; 15,791 and 15,165 spores were recovered from MF, EP, Re-EP and Re-MF, respectively. The number of morphotypes was 14, 13, 11 and 9 in Re-EP, EP, MF and Re-MF, respectively. The MF showed the highest diversity index (0.970), followed by EP, Re-EP and Re-MF. The MF showed a significantly higher average number of spores (2,058) compared to EP, Re-EP and Re-MF (1,365; 1,316 and 1,264, respectively). Out of 19 morphotypes, 5 (26 %) were observed in all land use types, while 4 (21 %) were observed exclusively in Re-EP. Percentage root colonisation was significantly higher in MF (approximate to 70 %) than in other land use types (52 - 53 %). The MF showed a higher soil moisture and total organic matter content than the rest of the study sites, with no significant difference in available P. The results indicate that the change of land use has clearly altered the abundance and composition of the AMF population.