The effect of land-use related diversity on plant-soil feedbacks and plant-community coexistence
Final Report Abstract
Recent research indicates that under field conditions aboveground insect herbivory affects the outcome of plant-soil feedbacks (PSFs) and thus influences plant performance and plant-community composition. In the Biodiversity Exploratories, we therefore tested the impact of land-use related biodiversity and aboveground herbivory by insects on species specific PSFs directly in the field. A combined herbivory-exclusion and PSF experiment that was performed along the gradient of land use intensity (i.e. herbivory intensity) revealed that without insect herbivores PSFs remained similar (both in direction and magnitude) along the land-use intensity gradient. However, when grown with aboveground insect herbivores the PSFs differed from those measured under herbivory exclusion and depended on the intensity of herbivory. This suggests that the relative importance of PSFs for plant-species performance in grassland communities decreases with increasing intensity of herbivory. Hence, land-use intensity – by influencing the abundance and diversity of aboveground insect herbivores and thus aboveground insect herbivory – affects the outcome of PSFs. Although these results highlight the importance of insect herbivory and land-use related effects on the outcome of PSFs, in PSF research it remains largely unknown how the intensity of aboveground herbivory impact the PSFs itself (i.e., how the amount of a previous damage influence the subsequent plant growth, via changes in soil conditions). Therefore, we performed a large field PSF experiment with one-year soil conditioning under different insect herbivory intensity levels followed by one-year response phase testing the effect of soil conditioning under controlled common garden conditions and field conditions. In the common garden experiment, we found that the intensity of aboveground insect herbivory did not affect soil legacy effects of plant growth (neither intraspecific nor interspecific PSF). This result was a bit surprising, but is most likely due to the fact that even smallest damage induced physiological responses in plants that in turn impact soil microbial communities via cross-induced exudation processes. In the field experiment, when herbivores were excluded, we found similar results as in the common garden experiment, but observed that when grown under herbivory the intensity of damage influenced the outcome of PSFs. In summary, the results obtained in this project contribute to a more comprehensive understanding of the importance of PSFs under natural conditions and how they are influenced by environmental interactions. Our results also show that PSFs itself are unaffected by land-use mediated herbivory effects but that the actual herbivory intensity impacts the outcome of PSFs, is soil-specific and that this selective herbivory drives the importance of PSFs for plant performance in plant communities.
Publications
- (2017) Soil temperature modifies effects of soil-biota on plant growth. Journal of Plant Ecology, 10; 808-821
Heinze, J., Gensch, S., Weber, E. & Joshi, J.
(See online at https://doi.org/10.1093/jpe/rtw097) - (2018) Plant-soil feedback effects can be masked by aboveground herbivory under natural field conditions. Oecologia, 186; 235-246
Heinze, J. & Joshi, J.
(See online at https://doi.org/10.1007/s00442-017-3997-y) - (2019) Plant-soil feedbacks of Plantago lanceolata in the field depend on plant origin and herbivory. Frontiers in Ecology and Evolution
Kirchhoff, L., Kirschbaum, A., Joshi, J., Bossdorf, O., Scheepens, J.F. & Heinze, J.
(See online at https://doi.org/10.3389/fevo.2019.00422) - (2019) The relative importance of plant-soil feedbacks for plant-species performance increases with decreasing intensity of herbivory. Oecologia. 190; 651-664
Heinze, J., Simons, N.K., Seibold, S., Wacker, A., Weithoff. G., Gossner, M.M., Prati, D., Bezemer, T.M. & Joshi, J.
(See online at https://doi.org/10.1007/s00442-019-04442-9) - (2020) The Next Step: Disentangling the Role of Plant-Soil Feedbacks in Plant Performance and Species Coexistence Under Natural Conditions. Frontiers in Ecology and Evolution
Heinze, J., Bezemer, M. & Joshi, J.
(See online at https://doi.org/10.3389/fevo.2020.00231)
