Nitrogen availability along an elevational transect in a tropical montane forest – Rwenzori, Uganda

To better understand environmental controls on N availability in tropical montane forests, we setup an elevational transect on Mt. Rwenzori in Uganda, ranging from 1264 to 2886 m a.s.l. Analysis of total N content and δ15N stable isotope composition in top 30 cm revealed a positive correlation between total N content and elevation.

Total N content increased four-fold between lowland to upper montane. Whereas soil δ15N decreased three-fold along the elevation transect. However, canopy N content showed negative correlation with elevation. and canopy N:P ratio revealed more N availability at the lower elevations and more P availability at higher elevations.