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A savanna response to precipitation intensity
Ryan S Berry1, Andrew Kulmatiski1
1Department of Wildland Resources and the Ecology Center, Utah State University, Logan, UT, United States of America.
Plos One
|April 8, 2017
Summary
Warmer climates mean fewer, more intense rain events. This experiment shows increased precipitation intensity drives woody plant encroachment by altering soil moisture and promoting deeper root growth.
Area of Science:
- Ecohydrology
- Plant Ecology
- Climate Change Science
Background:
- Global warming alters precipitation patterns, leading to less frequent but more intense rainfall events.
- Previous studies indicated that intense precipitation events can promote woody plant encroachment.
Purpose of the Study:
- To assess the long-term persistence of woody plant encroachment responses to altered precipitation intensity over five years.
- To investigate the ecohydrological effects of precipitation intensity on plant growth and soil moisture dynamics.
Main Methods:
- A five-year field experiment in Kruger National Park, South Africa, manipulating precipitation intensity in plots.
- Measurements included grass and woody plant growth, root development, soil moisture, and hydrological tracer uptake.
- Continuous soil moisture monitoring in treated and control plots.
Main Results:
- Increased precipitation intensity reduced surface soil water and increased deep soil water availability.
- Woody plants responded by increasing root growth and activity in deeper soil layers, enhancing their growth.
- While short-term growth responses diminished in the fifth year, accumulated woody plant biomass persisted.
Conclusions:
- Even small increases in precipitation intensity can significantly increase deep soil water availability.
- Plant growth responses to precipitation intensity are rapid but transient.
- Persistent increases in woody plant biomass, indicative of shrub encroachment, can result from occasional intense precipitation events.