Mammalian Herbivores Alter the Population Growth and Spatial Establishment of an Early-Establishing Grassland Species

PLoS One. 2016 Feb 5;11(2):e0147715. doi: 10.1371/journal.pone.0147715. eCollection 2016.

Abstract

Plant-herbivore interactions influence the establishment context of plant species, as herbivores alter the community context in which individual species establish, and the spatial relationship between individuals and their source population as plants invade. This relationship can be described using an establishment kernel, which takes into account movement through seed dispersal, and subsequent establishment of adults. Mammalian herbivores are hypothesized to influence plant population growth and establishment through a combination of consumption of seeds and seedlings, and movement of seeds. While the movement abilities of plants are well known, we have very few empirical mechanistic tests of how biotic factors like mammalian herbivores influence this spread potential. As herbivores of all sizes are abundant on the landscape, we asked the question, how do mammalian herbivores influence the population growth, spatial establishment, and the community establishment context of an early-recruiting native prairie legume, Chamaecrista fasciculata? We planted C. fasciculata in source populations within a four-acre tallgrass prairie restoration in plots with and without herbivores, and monitored its establishment with respect to distance from the source populations. We found that herbivores decreased population growth, and decreased the mean and range establishment distance. Additionally, C. fasciculata established more often without herbivores, and when surrounded by weedy, annual species. Our results provide insight into how the interactions between plants and herbivores can alter the spatial dynamics of developing plant communities, which is vital for colonization and range spread with fragmentation and climate change. Mammalian herbivores have the potential to both slow rates of establishment, but also determine the types of plant communities that surround invading species. Therefore, it is essential to consider the herbivore community when attempting to restore functioning plant communities.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Biodiversity
  • Ecosystem
  • Grassland*
  • Herbivory*
  • Mammals*
  • Population Dynamics
  • Population Growth

Grants and funding

Funding for this work was provided by the Iowa Living Roadway Trust Fund <<http://www.iowadot.gov/lrtf/>> project numbers: 90-00-LRTF-211 and 90-00-LRTF-307, the Audubon Toyota TogetherGreen Fellowship <<http://www.togethergreen.org/>>, the National Science Foundation GRFP <<https://www.nsfgrfp.org/>>, and the Iowa State University, Department of Ecology Evolution and Organismal Biology <<http://www.eeob.iastate.edu/>>. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.