Evidence for a fungal loop in shrublands

1. Dryland communities may mitigate the loss of limited resources by exchanging nutrients through subterranean fungal connections, termed fungal loops. In arid grasslands, fungal loops can influence community composition and primary productivity, yet their ecological significance across dryland systems remains unexplored. We investigated the functional role of fungal loops in nutrient translocation in a North American shrubland ecosystem.

2. We traced the movement of 15N from moss-dominated biocrusts to the dominant xeric shrub Larrea tridentata, and the movement of 13C from L. tridentata to biocrusts in plots established in situ in the Sonoran Desert. Measurements occurred at three time points spanning one week following a simulated 2.5 mm rainfall event, and at distances up to 1 m from tracer application. We also used ITS sequencing to investigate changes in fungal community composition in soils over the one-week period.

3. We discovered movement of 15N from biocrusts into L. tr...