Title: Invasion promotes invasion: Facilitation of C ₃ perennial grass dominance in mixed C ₃ /C ₄ grassland by an invasive C ₃ woody sprouter ( Prosopis glandulosa )

Abstract

1. In the Southern Great Plains (SGP) of the United States, encroachment of the native invasive woody legume, honey mesquite (Prosopis glandulosa Torr.), has caused a decline in C4 mid-grass abundance. Prosopis glandulosa invasion has also facilitated growth of the C3 mid-grass species, Texas wintergrass (Nassella leucotricha [Trin & Rupr.] Pohl) initially beneath its canopy but extending to interspaces between P. glandulosa as stand density increases. Little is known about the stability of the Prosopis/Nassella association or C4 grass recovery following P. glandulosa disturbance. 2. We quantified C3 and C4 grass production in interspaces, and basal cover in interspaces and P. glandulosa subcanopy microsites for 9 years following P. glandulosa suppression (top-kill) and compared this to untreated P. glandulosa woodland (woodland). 3. The Prosopis/Nassella association limited the window of C4 mid-grass recovery to only a few years. Nassella leucotricha dominated grass production during the first 3 years after top-kill. C4 mid-grass recovery began in year 4, but was interrupted by severe drought in years 5 through 7. Recovery resumed in year 8, due to above- average summer rainfall, but P. glandulosa regrowth was large enough by this time to limit C4 mid-grass production to a third of its potential. 4.more » Nassella leucotricha basal cover remained dominant and stable in woodland sub-canopy microsites, even during drought, and only briefly declined in top-kill subcanopy microsites before returning to pretreatment levels by year 8 as P. glandulosa regrowth increased and provided shade. 5. Synthesis and applications. A single suppression event had little impact on disrupting the Prosopis/Nassella association and allowing C4 mid-grass recovery. The coupling of a deciduous, N-fixing C3 woody species with this C3 perennial grass may be a vegetative “state” that is resistant to multiple woody suppression disturbances and permanently limits the transition back to C4 grassland.« less

Authors:

Ansley, Robert James  ^[1];

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Cooper, Caitlyn ^[2]; Zhang, Tian ^[2]

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+ Show Author Affiliations

1. Oklahoma State Univ., Stillwater, OK (United States). Natural Resource Ecology and Management Dept.
2. Texas A & M Univ., Vernon, TX (United States). Texas A & M AgriLife Research

Publication Date:

Mon Nov 04 00:00:00 EST 2019

Research Org.:

Oklahoma State Univ., Stillwater, OK (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1623550

Grant/Contract Number:  

SC0014664

Resource Type:

Accepted Manuscript

Journal Name:

Ecology and Evolution

Additional Journal Information:

Journal Volume: 9; Journal Issue: 23; Journal ID: ISSN 2045-7758

Publisher:

Wiley

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; 59 BASIC BIOLOGICAL SCIENCES; Environmental Sciences & Ecology; Evolutionary Biology