Ecological restoration efforts can increase the diversity and function of degraded areas. However, current restoration practices cannot typically reestablish the full diversity and species composition of remnant plant communities. Restoration quality can be improved by reintroducing key organisms from the native plant microbiome. In particular, root symbionts called arbuscular mycorrhizal (AM) fungi are critical in shaping grassland communities, but are sensitive to anthropogenic disturbance, which may pose a problem for grassland restoration. Studies of mycorrhizal amendments include inoculation densities of 2–10,000 kg of inocula per hectare. These studies report variable results that may depend on inocula volume, composition, or nativeness. Here we test eight different densities of native AM fungal amendment, ranging from 0 to 8,192 kg/ha in a newly installed prairie restoration. We found that native plant establishment benefited from native mycorrhizal inocula, resulting in improvements in native plant abundance, richness, and community diversity. Moreover, the application of very low densities of native mycorrhizal inocula, as suggested on commercial mycorrhizal products, were ineffective, and higher concentrations were required to benefit native plant abundance and community diversity. These data suggest that higher densities of mycorrhizal amendment or perhaps alternative distribution methods may be required to maximize benefits of native mycorrhizal amendments in restoration practices.
Restoration quality of native prairie can be improved by reintroducing key organisms from the native plant microbiome such as arbuscular mycorrhizal (AM) fungi. Here, we assess whether the positive effects of a native mycorrhizal inoculation observed during the first growing season remained at the end of the fourth growing season. In 2016, an experiment was initiated that assessed the response of a restored tallgrass prairie to an inoculation density gradient of native mycorrhizal fungi ranging from 0 to 8,192 kg/ha. First year results indicated that native plant establishment benefited from high but not low densities of native mycorrhizal inocula, resulting in improvements in native plant abundance, richness, and diversity. To assess whether these effects persist in later growing seasons, we resampled the prairie restoration in 2020 and analyzed the data similarly. Results from the fourth growing season indicated that the pattern of responses had persisted; the positive effects of inoculation observed during the first growing season remained after four growing seasons as demonstrated by improvements in total and native plant diversity and reduced non‐native abundance. Additionally, the low densities of mycorrhizal amendment that were not initially effective were found to reduce non‐native abundance in the fourth growing season, suggesting that low densities of mycorrhizal amendment can be amplified via positive plant‐AM fungal feedback to suppress weeds following the introduction of lesser amounts of AM fungi.
more » « less- NSF-PAR ID:
- 10411074
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Restoration Ecology
- Volume:
- 31
- Issue:
- 4
- ISSN:
- 1061-2971
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract The plant microbiome is critical to plant health and is degraded with anthropogenic disturbance. However, the value of re‐establishing the native microbiome is rarely considered in ecological restoration. Arbuscular mycorrhizal (AM) fungi are particularly important microbiome components, as they associate with most plants, and later successional grassland plants are strongly responsive to native AM fungi.
With five separate sites across the United States, we inoculated mid‐ and late successional plant seedlings with one of three types of native microbiome amendments: (a) whole rhizosphere soil collected from local old‐growth, undisturbed grassland communities in Illinois, Kansas or Oklahoma, (b) laboratory cultured AM fungi from these same old‐growth grassland sites or (c) no microbiome amendment. We also seeded each restoration with a diverse native seed mixture. Plant establishment and growth was followed for three growing seasons.
The reintroduction of soil microbiome from native ecosystems improved restoration establishment.
Including only native arbuscular mycorrhizal fungal communities produced similar improvements in plant establishment as what was found with whole soil microbiome amendment. These findings were robust across plant functional groups.
Inoculated plants (amended with either AM fungi or whole soil) also grew more leaves and were generally taller during the three growing seasons.
Synthesis and applications . Our research shows that mycorrhizal fungi can accelerate plant succession and that the reintroduction of both whole soil and laboratory cultivated native mycorrhizal fungi can be used as tools to improve native plant restoration following anthropogenic disturbance. -
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Losses of grasslands have been largely attributed to widespread land‐use changes, such as conversion to row‐crop agriculture. The remaining tallgrass prairie faces further losses due to biological invasions by non‐native plant species, often with resultant ecosystem degradation. Of critical concern for conservation, restoration of native grasslands has been met with little success following eradication of non‐native plants. In addition to the direct and indirect effects of non‐native invasive plants on beneficial soil microbes, management practices targeting invasive species may also negatively affect subsequent restoration efforts. To assess mechanisms limiting germination and survival of native species and to improve native species establishment, we established six replicate plots of each of the following four treatments: (1) inoculated with freshly collected prairie soil with native seeds; (2) inoculated with steam‐pasteurized soil with native seeds; (3) noninoculated with native seeds; or (4) noninoculated/nonseeded control. Inoculation with whole soil did not improve seed germination; however, addition of whole soil significantly improved native species survival, compared to pasteurized soil or noninoculated treatments. Inoculation with whole soil significantly decreased reestablishment of non‐native invasive
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This paper investigates the response of five tomato and five pepper varieties to native arbuscular mycorrhizal (AM) fungal inoculation in an organic farming system. The field experiment was conducted across a growing season at a working organic farm in Lawrence, KS, USA. The researchers hypothesized that native AM fungi inoculation would improve crop biomass production for both crop species, but that the magnitude of response would depend on crop cultivar. The results showed that both crops were significantly positively affected by inoculation. AM fungal inoculation consistently improved total pepper biomass throughout the experiment (range of +2% to +8% depending on the harvest date), with a +3.7% improvement at the final harvest for inoculated plants. An interaction between pepper variety and inoculation treatment was sometimes observed, indicating that some pepper varieties were more responsive to AM fungi than others. Beginning at the first harvest, tomatoes showed a consistent positive response to AM fungal inoculation among varieties. Across the experiment, AM fungi-inoculated tomatoes had +10% greater fruit biomass, which was driven by a +20% increase in fruit number. The study highlights the potential benefits of using native AM fungi as a soil amendment in organic farmed soils to improve pepper and tomato productivity.
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Abstract Arbuscular mycorrhizal (AM) fungi are root symbionts that can facilitate plant growth and influence plant communities by altering plant interactions with herbivores. Therefore, AM fungi could be critical for the conservation of certain rare plants and herbivores. For example, North American milkweed species are crucial hosts for monarch butterflies (
Danaus plexippus ). Understanding how mycorrhizal composition affects milkweeds will have direct impacts on the conservation and restoration of both increasingly threatened guilds. We present data from three studies on the effect of AM fungal composition on milkweed growth, latex production, and establishment. First, we grew seven milkweed species with and without a mixture of native mycorrhizal fungi. We assessed how important fungal composition is to milkweed growth and latex production by growing four milkweed species with seven fungal compositions, as single‐species inoculations with four native fungi, a mixture of native fungi, a single commercial fungus of presumably non‐native origin, and noninoculated controls. Finally, we assessed the field establishment of two milkweed species with and without native mycorrhizal inoculation. Milkweed species grew 98% larger and produced 82% more latex after inoculation with native mycorrhizae. Milkweeds were strongly affected by fungal composition; milkweeds were inhibited by commercial fungi (average of −14% growth) and showed variable but positive responses to native fungal species (average of +3% to +38% biomass). Finally, we found that restoration establishment was dependent on inoculation with native fungi and milkweed species. Overall, our findings indicate that some milkweed species (i.e.,Asclepias syriaca andA. incarnata ) are not responsive to mycorrhizal fungal presence or sensitive to mycorrhizal composition while others are, including endangered species (A. meadii ) and species of high conservation value (A. tuberosa ). We conclude that the reintroduction of native AM fungi could improve the establishment of desirable milkweed species and should be considered within strategies for plantings for monarch conservation.
