Rehabilitating downy brome (Bromus tectorum) - Invaded shrublands using imazapic and seeding with native shrubs

Suzanne M. Owen, Carolyn Hull Sieg, Catherine A Gehring

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Rehabilitation of downy brome-infested shrublands is challenging once this invasive grass dominates native communities. The effectiveness of imazapic herbicide in reducing downy brome cover has been variable, and there is uncertainty about the impacts of imazapic on native species. We used a before-after-control-impact (BACI) field experiment and greenhouse studies to (1) determine if imazapic herbicide applied at 132 g ai ha-1 (8 oz/ac-1) and seeding with two native shrub species (Wyoming big sagebrush [Artemisia tridentata] and Mexican cliffrose [Purshia mexicana]) reduced downy brome cover and promoted shrub establishment, (2) assess potential effects of imazapic on nontarget plant species and plant community composition, and (3) determine if imazapic affected downy brome or seeded shrub species when applied at different developmental stages. Seeding shrubs, alone, or in combination with imazapic application, did not significantly increase shrub density, possibly because of droughty conditions. In the field, imazapic reduced downy brome cover by 20% and nontarget forb cover by 25% and altered plant community composition the first year after treatment. Imazapic was lethal to downy brome at all growth stages in the greenhouse and reduced shrub germination by 50 to 80%, but older shrub seedlings were more tolerant of the herbicide. We conclude that a one-time application of imazapic combined with seeding shrubs was only slightly effective in rehabilitating areas with high downy brome and thatch cover and resulted in short-term impacts to nontarget species. These results highlight the need to treat downy brome infestations before they become too large. Also, removing thatch prior to treating with imazapic, although likely lethal to the native shrubs we studied, could increase the effectiveness of imazapic.

Original languageEnglish (US)
Pages (from-to)223-233
Number of pages11
JournalInvasive Plant Science and Management
Volume4
Issue number2
DOIs
StatePublished - Apr 2011

Fingerprint

imazapic
Bromus tectorum
shrublands
sowing
shrubs
thatch
herbicides
Purshia mexicana
plant communities
Artemisia tridentata subsp. wyomingensis
developmental stages
greenhouses
Artemisia tridentata
nontarget organisms
indigenous species
uncertainty

Keywords

  • Exotic species management
  • herbicide
  • nontarget species
  • rangeland seeding

ASJC Scopus subject areas

  • Plant Science

Cite this

Rehabilitating downy brome (Bromus tectorum) - Invaded shrublands using imazapic and seeding with native shrubs. / Owen, Suzanne M.; Sieg, Carolyn Hull; Gehring, Catherine A.

In: Invasive Plant Science and Management, Vol. 4, No. 2, 04.2011, p. 223-233.

Research output: Contribution to journalArticle

@article{98305b35fdff4e0c9759d9c53dd0dc70,
title = "Rehabilitating downy brome (Bromus tectorum) - Invaded shrublands using imazapic and seeding with native shrubs",
abstract = "Rehabilitation of downy brome-infested shrublands is challenging once this invasive grass dominates native communities. The effectiveness of imazapic herbicide in reducing downy brome cover has been variable, and there is uncertainty about the impacts of imazapic on native species. We used a before-after-control-impact (BACI) field experiment and greenhouse studies to (1) determine if imazapic herbicide applied at 132 g ai ha-1 (8 oz/ac-1) and seeding with two native shrub species (Wyoming big sagebrush [Artemisia tridentata] and Mexican cliffrose [Purshia mexicana]) reduced downy brome cover and promoted shrub establishment, (2) assess potential effects of imazapic on nontarget plant species and plant community composition, and (3) determine if imazapic affected downy brome or seeded shrub species when applied at different developmental stages. Seeding shrubs, alone, or in combination with imazapic application, did not significantly increase shrub density, possibly because of droughty conditions. In the field, imazapic reduced downy brome cover by 20{\%} and nontarget forb cover by 25{\%} and altered plant community composition the first year after treatment. Imazapic was lethal to downy brome at all growth stages in the greenhouse and reduced shrub germination by 50 to 80{\%}, but older shrub seedlings were more tolerant of the herbicide. We conclude that a one-time application of imazapic combined with seeding shrubs was only slightly effective in rehabilitating areas with high downy brome and thatch cover and resulted in short-term impacts to nontarget species. These results highlight the need to treat downy brome infestations before they become too large. Also, removing thatch prior to treating with imazapic, although likely lethal to the native shrubs we studied, could increase the effectiveness of imazapic.",
keywords = "Exotic species management, herbicide, nontarget species, rangeland seeding",
author = "Owen, {Suzanne M.} and Sieg, {Carolyn Hull} and Gehring, {Catherine A}",
year = "2011",
month = "4",
doi = "10.1614/IPSM-D-10-00054.1",
language = "English (US)",
volume = "4",
pages = "223--233",
journal = "Invasive Plant Science and Management",
issn = "1939-7291",
publisher = "Allen Press Inc.",
number = "2",

}

TY - JOUR

T1 - Rehabilitating downy brome (Bromus tectorum) - Invaded shrublands using imazapic and seeding with native shrubs

AU - Owen, Suzanne M.

AU - Sieg, Carolyn Hull

AU - Gehring, Catherine A

PY - 2011/4

Y1 - 2011/4

N2 - Rehabilitation of downy brome-infested shrublands is challenging once this invasive grass dominates native communities. The effectiveness of imazapic herbicide in reducing downy brome cover has been variable, and there is uncertainty about the impacts of imazapic on native species. We used a before-after-control-impact (BACI) field experiment and greenhouse studies to (1) determine if imazapic herbicide applied at 132 g ai ha-1 (8 oz/ac-1) and seeding with two native shrub species (Wyoming big sagebrush [Artemisia tridentata] and Mexican cliffrose [Purshia mexicana]) reduced downy brome cover and promoted shrub establishment, (2) assess potential effects of imazapic on nontarget plant species and plant community composition, and (3) determine if imazapic affected downy brome or seeded shrub species when applied at different developmental stages. Seeding shrubs, alone, or in combination with imazapic application, did not significantly increase shrub density, possibly because of droughty conditions. In the field, imazapic reduced downy brome cover by 20% and nontarget forb cover by 25% and altered plant community composition the first year after treatment. Imazapic was lethal to downy brome at all growth stages in the greenhouse and reduced shrub germination by 50 to 80%, but older shrub seedlings were more tolerant of the herbicide. We conclude that a one-time application of imazapic combined with seeding shrubs was only slightly effective in rehabilitating areas with high downy brome and thatch cover and resulted in short-term impacts to nontarget species. These results highlight the need to treat downy brome infestations before they become too large. Also, removing thatch prior to treating with imazapic, although likely lethal to the native shrubs we studied, could increase the effectiveness of imazapic.

AB - Rehabilitation of downy brome-infested shrublands is challenging once this invasive grass dominates native communities. The effectiveness of imazapic herbicide in reducing downy brome cover has been variable, and there is uncertainty about the impacts of imazapic on native species. We used a before-after-control-impact (BACI) field experiment and greenhouse studies to (1) determine if imazapic herbicide applied at 132 g ai ha-1 (8 oz/ac-1) and seeding with two native shrub species (Wyoming big sagebrush [Artemisia tridentata] and Mexican cliffrose [Purshia mexicana]) reduced downy brome cover and promoted shrub establishment, (2) assess potential effects of imazapic on nontarget plant species and plant community composition, and (3) determine if imazapic affected downy brome or seeded shrub species when applied at different developmental stages. Seeding shrubs, alone, or in combination with imazapic application, did not significantly increase shrub density, possibly because of droughty conditions. In the field, imazapic reduced downy brome cover by 20% and nontarget forb cover by 25% and altered plant community composition the first year after treatment. Imazapic was lethal to downy brome at all growth stages in the greenhouse and reduced shrub germination by 50 to 80%, but older shrub seedlings were more tolerant of the herbicide. We conclude that a one-time application of imazapic combined with seeding shrubs was only slightly effective in rehabilitating areas with high downy brome and thatch cover and resulted in short-term impacts to nontarget species. These results highlight the need to treat downy brome infestations before they become too large. Also, removing thatch prior to treating with imazapic, although likely lethal to the native shrubs we studied, could increase the effectiveness of imazapic.

KW - Exotic species management

KW - herbicide

KW - nontarget species

KW - rangeland seeding

UR - http://www.scopus.com/inward/record.url?scp=79959330925&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79959330925&partnerID=8YFLogxK

U2 - 10.1614/IPSM-D-10-00054.1

DO - 10.1614/IPSM-D-10-00054.1

M3 - Article

VL - 4

SP - 223

EP - 233

JO - Invasive Plant Science and Management

JF - Invasive Plant Science and Management

SN - 1939-7291

IS - 2

ER -