My third dissertation chapter is now out in Ecology! This paper used a factorial experiment of precipitation manipulation and human management (hay harvest) in a temperate mixed-grass prairie to examine 1) how two drivers, altered precipitation and biomass removal, can synergistically affect abiotic factors and plant communities and 2) how these effects can cascade upward, impacting the arthropod food web.
This paper was a result of a collaboration with Dr. Lara Souza’s lab and I worked closely with her Ph.D. candidate, Karen Castillioni. At Kessler Atmospheric and Ecological Field Station, the Souza lab set up a seven-level precipitation manipulation gradient. Using rain-out shelters, they excluded up to 100% of precipitation on plots in addition to adding +50% precipitation to other plots (Fig. 1).
I collected arthropods from plots in 2017 and 2018 and tested 3 non-exclusive hypotheses detailing how direct and indirect effects of drought and hay harvest work synergistically to affect the plant and arthropod communities in a mixed-grass prairie. I found that both drought and hay harvest increased soil surface temperature while drought decreased soil moisture. Arthropod abundance decreased with low soil moisture and, contrary to our predictions, decreased with increased plant biomass. Arthropod diversity increased with soil moisture, decreased with high surface temperatures, and tracked arthropod abundance but was surprisingly unaffected by plant diversity or quality. Our results demonstrate that arthropod abundance is directly constrained by abiotic factors and plant biomass and in turn constrains local arthropod diversity.
This was a fun project to work on. You can click here to read the full paper.
Rebecca M. Prather 