Masters Theses

Date of Award

8-2007

Degree Type

Thesis

Degree Name

Master of Science

Major

Wildlife and Fisheries Science

Major Professor

Craig A. Harper

Committee Members

Gary E. Bates, Mathew J. Gray

Abstract

Conversion of tall fescue (Festuca arundinacea) to managed native warm-season grasses (nwsg) and associated forbs benefits many wildlife species that depend on early successional habitat. Planting nwsg, however, may not be necessary depending on the composition of the seedbank. Treatments were implemented in a randomized complete block design with replication during 2003 and 2004 at three study sites across Tennessee to determine the effects of seasonal herbicide applications and disking on tall fescue eradication and resulting vegetation composition and structure. Treatments included: fall glyphosate (2.2 kg ai/ha; Gly-4 2qt/ac); fall glyphosate followed by winter disking; fall imazapic (0.2 kg ai/ha; Plateau 12 oz/ac); fall imazapic followed by winter disking; spring glyphosate; spring glyphosate followed by fall disking; spring imazapic; and spring imazapic followed by fall disking. Vegetation composition and structure were measured June – September, and November 2004 and February, April, and June – September 2005. All treatments reduced tall fescue cover compared to control one growing season after treatment. Fall herbicide applications with and without disking decreased tall fescue cover more than spring treatments when measured two growing seasons after treatment. Reduction in tall fescue improved openness at ground level during the brooding season and angle of obstruction during the wintering period for bobwhites. Disking following herbicide application increased cover of bobwhite food plants, including common ragweed (Ambrosia artemisifolia), beggar’s-lice (Desmodium spp.), and beggar-ticks (Bidens spp.). Imazapic increased cover of desirable nwsg, such as broomsedge bluestem (Andropogon virginicus); however on 2 sites, imazapic applications resulted in increased cover of orchardgrass (Dactylis glomerata), which was structurally identical to tall fescue. Fall glyphosate applications are recommended to eradicate tall fescue. If certain undesirable plants are suspected to germinate from the seedbank after tall fescue is removed, an imazapic application may be necessary in April or May to control species such as johnsongrass (Sorghum halapense), crabgrass (Digitaria sanguinalis), and yellow nutsedge (Cyperus esculentus).

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