Canopy Interception for a Tallgrass Prairie under Juniper Encroachment

PLoS One. 2015 Nov 6;10(11):e0141422. doi: 10.1371/journal.pone.0141422. eCollection 2015.

Abstract

Rainfall partitioning and redistribution by canopies are important ecohydrological processes underlying ecosystem dynamics. We quantified and contrasted spatial and temporal variations of rainfall redistribution for a juniper (Juniperus virginiana, redcedar) woodland and a tallgrass prairie in the south-central Great Plains, USA. Our results showed that redcedar trees had high canopy storage capacity (S) ranging from 2.14 mm for open stands to 3.44 mm for closed stands. The canopy funneling ratios (F) of redcedar trees varied substantially among stand type and tree size. The open stands and smaller trees usually had higher F values and were more efficient in partitioning rainfall into stemflow. Larger trees were more effective in partitioning rainfall into throughfall and no significant changes in the total interception ratios among canopy types and tree size were found. The S values were highly variable for tallgrass prairie, ranging from 0.27 mm at early growing season to 3.86 mm at senescence. As a result, the rainfall interception by tallgrass prairie was characterized by high temporal instability. On an annual basis, our results showed no significant difference in total rainfall loss to canopy interception between redcedar trees and tallgrass prairie. Increasing structural complexity associated with redcedar encroachment into tallgrass prairie changes the rainfall redistribution and partitioning pattern at both the temporal and spatial scales, but does not change the overall canopy interception ratios compared with unburned and ungrazed tallgrass prairie. Our findings support the idea of convergence in interception ratio for different canopy structures under the same precipitation regime. The temporal change in rainfall interception loss from redcedar encroachment is important to understand how juniper encroachment will interact with changing rainfall regime and potentially alter regional streamflow under climate change.

Publication types

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

MeSH terms

  • Forests
  • Grassland*
  • Juniperus / growth & development*
  • Rain*
  • Spatio-Temporal Analysis
  • Trees

Grants and funding

The field equipment installation, data collection were completed with support from the U. S. Geological Survey/National Institutes for Water Research USGS104G (G09AP00146 https://niwr.net/public/Migration/niwr.net) and USGS OWRRI grants. The data analysis, re-analysis, and paper writing were partially supported with funding from National Science Foundation/Experimental Program to Stimulate Competitive Research (EPSCoR http://www.nsf.gov/od/iia/programs/epscor/nsf_oiia_epscor_index.jsp) via grant NSF-1301789, NSF Dynamics of Coupled Natural and Human Systems (CNH) program (DEB-1413900 http://www.nsf.gov/div/index.jsp?div=DEB), and United States Department of Agriculture/National Institute of Food and Agriculture (2014-67010-21653 http://nifa.usda.gov/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.