A Hidden Obstacle to Restoration in the Sagebrush Steppe

The sagebrush steppe is a unique ecosystem facing a number of threats to its native flora and fauna. Restoration efforts to counteract the effects of wildfires, invasive species, and anthropogenic disturbances are widespread, but success rates vary. A. tridentata , a keystone species of sagebrush, is the focus of numerous reseeding efforts. Unfortunately, many of the scattered seeds never germinate.

Little is known about how pathogenic fungi found in the soil might influence sagebrush seed germination rate. We want to know which fungal pathogens reduce A. tridentata seed survival, and how environmental conditions and overwintering influence seed-pathogen interactions.

Fungal isolates collected from dead A. tridentata seeds were subcultured, and their spores were harvested to produce inoculum. The inoculum was applied to groups of surface-sterilized A. tridentata seeds collected from three different sites, and a spore-less solution was applied as a negative control. The seeds were observed until all seeds had germinated and/or succumbed to the fungal pathogen.

Seeds inoculated with spores from the fungal isolate showed an increase in mortality and a decrease in successful germination compared to the negative control.

The success rate of sagebrush reseeding could be improved by identifying fungal pathogens present in sagebrush steppe soil.