Eragrostis curvula effects on above and below-ground plant species richness and diversity

Monitoring and managing the soil seed bank is fundamental to land management as it constitutes the future generations of invasive plant communities. Invasive plants have traits that result in high recruitment through increased seed generation, short seed dormancy, and phenotypic plasticity. Furthermore, invasive plants with growth forms that inhibit the growth and recruitment of other species can lead to monocultures and associated reduction in above-ground biodiversity, potentially negatively impacting the soil seed bank diversity and ecosystem functions and services. Eragrostis curvula is one such species that has many of these invasive traits, including high propagule generation, and can exclude plant species from establishing in the above-ground population, thus negatively impacting above-ground biodiversity, as measured by species richness and Shannon diversity index. However, our findings suggest it has not significantly impacted the soil seed bank species diversity or richness across eight sites within the Snowy Monaro region when competition is removed as a limiting factor. Our findings provide valuable information on a path to invasive plant species management. If E. curvula above-ground biomass is controlled, other species dormant in the soil seed bank may recruit in the ecosystem, provided they remain viable in the soil seed bank. However, to date, our research has not investigated the species composition of these sites in detail. With such a high density of potentially germinating seeds in a soil seed bank and the adverse effects the species can have on the above-ground species diversity and richness, E. curvula needs integrated management to mitigate its spread and ecosystem and economic impact.