Continued changes in temperature and soil moisture influence the plant and soil feedback dynamics of native and non-native tallgrass prairie grasses
Negative feedback is a well-documented mechanism that occurs between plant and soil microbial communities, which promotes biological diversity. In addition to the accumulation of soil pathogens, shifts in the AM fungal community also contribute to the maintenance of these feedback loops. In the face of a rapidly changing climate, more temporal approaches are needed to understand the consequences of extreme climate events on ecological mechanisms such as this. Additionally, the presence of non-native species can generate positive feedback loops, which increase the dominance of non-native species. This can be further influenced by environmental conditions as well. Tallgrass prairie native (Schizachyrium scoparium,) and invasive (Bothriochloa ischaemum) C4 grasses were grown in a full factorial combination of altered soil communities trained from a previous climate perturbation experiment and a full factorial combination of temperature (29 °C/24 °C ) and soil moisture (100%/75% field capacity) treatments identical to the previous experiment. Plants were grown for 14 weeks in a controlled greenhouse environment. Shoot and root biomass were measured along with bi-weekly measurements of height and leaves. We did this to assess the continued effects of shifts in temperature and soil moisture on plant-soil interactions between native and non-native prairie grasses.
Results show that aboveground biomass production of S. scoparium was not promoted by its own soil relative to soil trained with B. ischaemum, indicating the absence of a strong positive feedback between S. scoparium and its own soil. Additionally, soil trained by S. scoparium under decreased soil moisture and cool temperatures increased biomass production of B. ischaemum relative to soil trained by S. scoparium in warm conditions. However, drought conditions reduced S. scoparium biomass production regardless of soil legacy. This indicated that soils previously trained under the non-native B. ischaemum did not affect the susceptibility of the native S. scoparium to drought. These results suggest that soil communities trained under the non-native grass differentially influence growth and survivorship of native species relative to their non-native counterparts and that the environmental conditions with which these grasses were grown influence the plant-soil dynamics of native and invasive grasses.