Amendments Activate Soil Seed Bank in Greenhouse Study, Indicating Potential for Improved Restoration Outcomes

Abstract

The potential for soil seed banks to contribute to effective habitat restoration is not well understood, but seed bank activation could offer a cost-effective solution for vegetation establishment of degraded sites. Our study site had been affected by deforestation and aeolian contamination from copper smelting, resulting in significant erosion and large unvegetated patches. To evaluate the potential value of soil seed bank activation for restoring intermountain grasslands and mountain forests, we set up a greenhouse-scale seed bank experiment to test the effect of nutrient amendments previously utilized in field trials in the study area. We also tested the effect of native seed augmentation on diversity. Our results showed that the tested soils had a significant seed bank as 16 volunteer plant species emerged, of which ten were native and six were non-native. Nutrient amendments did not affect grass seedling numbers, but one treatment (the addition of biofertilizer) increased forb numbers. All treatments, except synthetic fertilizer increased the total aboveground biomass of the emerging seedlings. Native seed augmentation increased grass and forb seedling numbers, but, the impact of nutrient amendments changed with seed augmentation, and certain nutrient treatments even reduced seedling emergence. While biofertilizer combined with mycorrhizae did not affect grass or forb seedling numbers, it did increase plant biomass. Activating soil seed banks with nutrient additions may be a feasible approach for ecological restoration. However, there are significant differences among treatments. Further studies would be necessary to reveal the specific effects of nutrient addition on soil seed bank activation, especially in field settings.