Ecophysiological responses of native invasive woody Juniperus virginiana L. to resource availability and stand characteristics in the semiarid grasslands of the Nebraska Sandhills

Authors

Joseph Msanne, University of Nebraska-LincolnFollow
Tala Awada, University of Nebraska - LincolnFollow
N. M. Bryan, University of Nebraska - Lincoln
Walter H. Schacht, University of Nebraska - LincolnFollow
Rhae A. Drijber, University of Nebraska - LincolnFollow
Y. Li, Chinese Academy of Sciences
X. Zhou, Campbell Scientific Inc.
Jane A. Okalebo, University of Nebraska-LincolnFollow
David A. Wedin, University of Nebraska - LincolnFollow
James R. Brandle, University of Nebraska - LincolnFollow
J. Hiller, University of Nebraska-LincolnFollow

Date of this Version

2017

Citation

PHOTOSYNTHETICA 55 (2): 219-230, 2017, DOI: 10.1007/s11099-016-0683-y.

Comments

“© The Author(s).” This article is published with open access at link.springer.com

Abstract

Vegetation in grasslands is changing at an unprecedented rate. In the Nebraska Sandhills, this shift is attributed in part to encroachment of the woody species Juniperus virginiana. We investigated changes in resource availability and their feedback on seasonal trends in photosynthetic characteristics of J. virginiana trees scattered in open grasslands vs. a dense 57-year-old stand. Dense stand exhibited lower volumetric soil water content, NH₄ ⁺, NO₃ ^–, and δ¹³C, as well as foliage δ¹³C, δ¹⁵N, and N content, compared to grasslands. Water potential was higher in trees in grasslands compared to dense stand. J. virginiana in dense stand exhibited similar trends to trees in grasslands for net photosynthetic rate (P_N), stomatal conductance, transpiration, maximum photochemical efficiency of PSII, maximum carboxylation velocity, and maximum rate of electron transport. P_N peaked early summer and declined in the fall, with trees in open grasslands lagging behind those in dense stand. Plasticity of this species may place it at a competitive advantage in the Sandhills, further altering grasslands vegetation and ecosystem processes.