Document Type

Article

Publication Title

Diversity

Publication Date

Winter 2-2024

Keywords

Castilleja, grassland management, nutrients, Pedicularis, species richness, tallgrass prairie

Abstract

Root hemiparasites infiltrate the vascular tissue of host roots to acquire water and nutrients, which often reduces host growth. Hemiparasites are postulated to be keystone species in grassland communities if they suppress dominant species and increase plant community biodiversity, and ecosystem engineers if they increase nutrient accessibility for surrounding species. We examined keystone effects by evaluating species richness and evenness in 1 m2 plots in a recent prairie restoration where Castilleja sessiliflora was naturally present or absent, and in a longer-established prairie restoration with or without Pedicularis canadensis. We examined ecosystem engineer effects by determining nitrate and phosphate concentrations under, 25 cm from, and 50 cm from hemiparasites, and in the center of hemiparasite-free plots. On the C. sessiliflora site, plots with the hemiparasites had higher species richness due to more forbs and higher floristic quality, consistent with the keystone species hypothesis. Soil phosphate levels were also greater in plots with C. sessiliflora present, consistent with the hypothesis of ecosystem engineering by this hemiparasite. In contrast, plots with/without P. canadensis showed no associations of any community metrics with the hemiparasite, and no correspondence between the presence of hemiparasites and soil nutrients. Although hemiparasites can increase grassland community heterogeneity, the effect is not universal, and the direction and strength of effects likely depends on local conditions.

Funding Source

Friends of Nachusa Grasslands, the Beta Lambda Chapter of the Phi Sigma Biological Honors Society, and the Graduate School of Illinois State University.

Comments

Data are available in a file called Scheidel&Borowicz24-Effects of Hemiparasites in Grassland Restorations Are Not Universal-DATA

DOI

doi.org/10.3390/d16020000

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