Abstract
- The encroachment of woody plants into grasslands is an ongoing global
problem that is largely attributed to anthropogenic factors such as
climate change and land management practices. Determining the
mechanisms that drive successful encroachment is a critical step
towards planning restoration and long-term management strategies.
Feedbacks between soil and aboveground communities can have a large
influence on the fitness of plants and must be considered as
potentially important drivers for woody encroachment.
- We conducted a plant-soil feedback experiment in a greenhouse between
eastern redcedar Juniperus virginiana and four common
North American prairie grass species. We assessed how soils that had
been occupied by redcedar, a pervasive woody encroacher in the Great
Plains of North America, affected the growth of big bluestem, little
bluestem smooth brome, and western wheatgrass over time. We evaluated
the effect of redcedar on grass performance by comparing the height
and biomass of individuals of each grass species that were grown in
live or sterilized conspecific or redcedar soil.
- We found that redcedar created a negative plant-soil feedback that
limited the growth of two species. These effects were found in both
live and sterilized redcedar soils, indicating redcedar may exude an
allelochemical into the soil that limits grass growth.
- Synthesis. By evaluating the strength and direction of
plant-soil feedbacks in the encroaching range, we can further our
understanding of how woody pants successfully establish in new plant
communities. Our results demonstrate that plant-soil feedback created
by redcedar inhibits the growth of certain grass species. By creating
a plant-plant interaction that negatively affects competitors,
redcedars increase the probability of seedling survival until they can
grow to overtop their neighbors. These results indicate plant-soil
feedback is a mechanism of native woody plant encroachment that could
be important in many systems yet is understudied.