Native Plant Establishment Success Influenced Yb Spotted Knapweed (Centaurea Stoebe) Control Method

Grand Valley State University ScholarWorks@GVSU Funded Articles Open Access Publishing Support Fund 2014 Native Plant Establishment Success Influenced yb Spotted Knapweed (Centaurea stoebe) Control Method Laurelin M. Martin Grand Valley State University Neil W. MacDonald Grand Valley State University, [email protected] Tami E. Brown Grand Valley State University Follow this and additional works at: https://scholarworks.gvsu.edu/oapsf_articles Part of the Biology Commons ScholarWorks Citation Martin, Laurelin M.; MacDonald, Neil W.; and Brown, Tami E., "Native Plant Establishment Success Influenced by Spotted Knapweed (Centaurea stoebe) Control Method" (2014). Funded Articles. 15. https://scholarworks.gvsu.edu/oapsf_articles/15 This Article is brought to you for free and open access by the Open Access Publishing Support Fund at ScholarWorks@GVSU. It has been accepted for inclusion in Funded Articles by an authorized administrator of ScholarWorks@GVSU. For more information, please contact [email protected]. RESEARCH ARTICLE Native Plant Establishment Success Influenced by Spotted Knapweed (Centaurea stoebe) Control Method Laurelin M. Martin, Neil W. MacDonald and Tami E. Brown ABSTRACT Invasive species frequently need to be controlled as part of efforts to reestablish native species on degraded sites. While the effectiveness of differing control methods are often reported, the impacts these methods have on the establishment of a native plant community are often unknown. To determine methods that effectively reduce spotted knapweed (Cen- taurea stoebe) while enhancing native species establishment, we tested 12 treatment combinations consisting of an initial site preparation (mowing, mowing + clopyralid, or mowing + glyphosate), in factorial combination with annual adult knapweed hand pulling and/or burning. We established 48 plots and applied site preparation treatments during summer 2008, seeded 23 native forbs and grasses during spring 2009, pulled adult knapweed annually from 2009–2012, and burned in the early spring 2012. During July of 2011 and 2012, percent cover of all species was visually estimated. By 2011, seeded species had established in all treatment plots, including plots that retained greater than 50% knapweed cover, indicating that native species successfully established despite knapweed dominance. Mowing alone had no longterm impacts on community development. Clopyralid favored non-native grass establishment, while glyphosate encouraged non-native forbs. Clopyralid had minimal impacts on native forb establishment, but did effectively control knapweed. Pulling reduced knapweed cover, increased non-native grass cover and enhanced native species establishment. Burn- ing had little impact, possibly due to low intensity and unseasonable weather. On the heavily invaded site we studied, combining the use of clopyralid with hand pulling effectively controlled knapweed and favored the establishment of seeded native grasses and forbs. Keywords: community development, ecological restoration, invasive plants, Michigan prairie, native diversity uccessful restoration often requires control efforts (D’Antonio and Mey- while also allowing for either unin- Sthe concomitant control of inva- erson 2002). hibited or accelerated restoration of a sive species, which otherwise will Control efforts targeting invasive native community. hinder the restoration effort, espe- species can also inhibit the develop- Spotted knapweed (Centaurea stoebe; cially on degraded land. Following ment of a native community (Erskine hereafter knapweed) has invaded over invasive plant establishment, resto- Ogden and Rejmánek 2005, Rinella et 2.9 million hectares in North America ration of a native plant community al. 2009, Ortega and Pearson 2011). (DiTomaso 2000) and can success- becomes very challenging (DiTomaso Successful control of one invasive fully invade plant communities on 2000). Invasive plants are capable of plant may open the community to both remnant and disturbed sites. altering ecosystem function (Weiden- further invasion or surges in domi- Following invasion, knapweed forms hamer and Callaway 2010), nutrient nance of other non-natives already peripherally enlarging monocultures cycles (Ehrenfeld et al. 2001, Allison present (Zavaleta et al. 2001, Ortega that seed profusely, have allelopathic and Vitousek 2004), and disturbance and Pearson 2011). Unfortunately, effects on susceptible species, and regimes (D’Antonio and Vitousek it is infrequent for studies targeting negatively impact ecosystem richness 1992, Brooks et al. 2004), resulting invasive species control to report on and diversity (Watson and Renney in a continuing need for longterm the effects of these treatments on the 1974, Schirman 1981, Tyser 1992, restored plant community (Reid et Sheley et al. 1998, Kedzie-Webb et Ecological Restoration Vol. 32, No. 3, 2014 al. 2009, Kettenring and Reinhardt al. 2001, Thorpe et al. 2009). While ISSN 1522-4740 E-ISSN 1543-4079 Adams 2011). Thus, it is highly desir- it is known that knapweed can be ©2014 by the Board of Regents of the able to determine which methods controlled using a variety of methods University of Wisconsin System. can be used to control invasive plants including herbicide application (Rice 282 • September 2014 ECOLOGICAL RESTORATION 32:3 et al. 1997), biological controls (Story reduced knapweed cover and increased average, is 369 mm (NCDC 2009). et al. 2006, but see Ortega et al. 2012), native species diversity, cover, and During the study, total precipita- and controlled burning (MacDonald floristic quality. These treatments tion from April through August et al. 2007), resurgence of knapweed included factorial combinations of was 386 mm during 2009, 381 mm is very likely without the formation mowing alone or mowing in combina- during 2010, 510 mm during 2011 of a competitive, native community tion with a single application of either and 302 mm during 2012, as deter- (Sheley et al. 1996), especially on sites a broadleaf-specific herbicide (clopy- mined from the Muskegon, Michi- in which seeds from previous infes- ralid), or broad-spectrum herbicide gan National Weather Service station tations are present in the seed bank (glyphosate), hand pulling of adult (NCDC 2014). Normal tempera- (Sheley et al. 1996, Carpinelli et al. knapweed, and burning. Based on our tures for the area are 18.3 °C in June, 2004). As diverse native plant com- review of published literature and pre- 21.1 °C in July, and 20.3 °C in August munities are more capable of resist- vious study in adjacent areas (Mac- (NCDC 2014). Temperature averages ing knapweed invasion (Kennedy et Donald et al. 2003, 2007), we hypoth- during the study for June, July and al. 2002, Bakker and Wilson 2004, esized: (1) a single mowing would August respectively were 18.9 °C, Maron and Marler 2007), it is impor- have little longterm impacts, (2) use 18.8 °C, and 19.9 °C for 2009, tant during any restoration project to of clopyralid would reduce knapweed 19.8 °C , 23.9 °C, and 23.9 °C for ensure that such diverse native systems cover and lead to increases in grass 2010, 19.7 °C, 24.1 °C, and 21.8 °C are reestablished. cover, (3) application of glyphosate for 2011, and 20.8 °C, 25.4 °C, and Targeting native plant establishment would reduce competition during 21.2 °C for 2012 (NCDC 2014). in combination with knapweed con- native species seedling establishment, Thus, while 2009 and 2010 experi- trol requires knowledge on how com- but allow for rapid knapweed resur- enced relatively normal weather, in munity development will be affected. gence, (4) pulling of adult knapweed 2011 there was above average precipi- For instance, the controlled burning would reduce knapweed cover, allow- tation, and in 2012, low precipitation of native, fire-adapted species stimu- ing for increased native species estab- and high temperatures led to a severe lates flower stalk production, facili- lishment due to decreased competi- drought conditions lasting from mid- tates seedling establishment, enhances tion, (5) controlled burns performed June through mid-October (NDMC productivity, and increases warm-sea- in mid-Spring would both reduce 2013). son grasses (Old 1969, Abrams et al. knapweed and increase native warm- Prior to establishment of the Bass 1986, Howe 1994, Maret and Wilson season grasses, (6) the broadleaf-spe- River Recreation Area, the site was 2005). In addition, carefully timed cific herbicide treatment (clopyralid) highly disturbed by extensive gravel burns can reduce knapweed cover would result in higher grass cover, mining in the mid-1900s (MacDon- and seed viability (Emery and Gross while the broad-spectrum herbicide ald et al. 2003), leaving a persistent 2005, MacDonald et al. 2007, Ver- (glyphosate) + pulling + burning treat- ruderal plant community infested by meire and Rinella 2009). Applying ment and the mowing + pulling + spotted knapweed (MacDonald et al. effective control methods, but rely- burning treatment would lead to the 2003, 2007, 2013). Knapweed was the ing on a remnant native seed bank highest native diversity. Within the dominant invasive plant at our study or colonization from nearby sites for context of these hypotheses, the goal site prior to the initiation of our study native species establishment may result of the restoration was to establish a with 60% to 70% cover based upon in communities with lower species diverse native plant community that the total pre-treatment knapweed den- richness (Heslinga and Grese 2010), would effectively resist reinfestation

Load more