COS 88-7
Inoculation with native AM fungi improves establishment and growth of late successional plant species in prairie restorations
Evidence is accumulating that arbuscular mycorrhizal (AM) fungi may play a vital role in grassland community dynamics. My previous greenhouse studies suggest that fast growing early successional plants not responsive to AM fungi, while late successional plants are highly mycorrhizally responsive and demonstrate greater specificity towards individual AM fungal species. Interestingly, grassland restorations often take place at sites with disturbed soil fungal communities and are often are missing many late successional plant species, which is consistent with missing AM fungi limiting their successful reestablishment.
To see how grassland plants respond to different prairie AM fungal communities during a grassland restoration, seedlings of eight early and eight late successional plant species were planted into 1.5 meter plots. Plants in a replicated plots were inoculated with one of four fungal species, a mixture of four fungal species, or not inoculated. The entire experiment was also seeded with a diverse prairie mixture. Plant growth, fecundity, and community diversity in response to fungi was using a mixed model while plant survival was analyzed using a generalized linear mixed model. We decomposed plant response into four A PRIORI orthogonal contrasts assessing the effect of inoculation, growth differences among fungal species, and those interactions by plant successional stage.
Results/Conclusions
Plant species (p<0.0001) and inoculation (p<0.0001) were the largest predictors of plant survival, where inoculation improved survival by 40% (p<0.0001). Inoculation with AM fungi also improved plant leaf number (p=0.03), height (p=0.007) and flower number (p=0.03). Fungal species had significant effects on plant productivity (p=0.03) and fecundity (p=0.04). We found two fungal species which promoted plants better than or similar to the fungal mixture, while two other fungal species were generally less effective than the fungal mixture but more effective than having no fungal amendments at promoting plant growth. We found a significant fungal species by successional stage interaction for plant fecundity which suggested that inoculation (0=0.03) and inoculation with certain AM fungal species (p=0.1) was more important for late successional species.
These results suggest that prairie fungal inoculations are better than resident AM fungal communities at improving plant growth and establishment in prairie grassland restorations. These results also suggest that inoculation with certain AM fungal species can have large impacts on plant growth and survival, especially for late successional plant species. We recommend using AM fungal inoculations in grassland restorations that target prairie diversity, plant productivity, pollinator habit, or those which have low seedling establishment or survival.