Invasive Plant Science and Management最新文献

{"title":"Effectiveness of integrating mowing and systemic herbicides applied with a weed wiper for Sporobolus indicus var. pyramidalis management in Florida","authors":"Jose C.L.S. Dias, Temnotfo L. Mncube, Brent A. Sellers, Jason A. Ferrell, Stephen F. Enloe, Joao M.B. Vendramini, Philipe Moriel","doi":"10.1017/inp.2024.16","DOIUrl":"https://doi.org/10.1017/inp.2024.16","url":null,"abstract":"<jats:italic>Sporobolus indicus</jats:italic> (L.) R. Br. var. <jats:italic>pyramidalis</jats:italic> (P. Beauv.) Veldkamp is an invasive species in grasslands, and herbicide application has been the most efficient management method to suppress this weed. Experiments were conducted to determine the effects of wiping glyphosate and hexazinone on <jats:italic>S. indicus</jats:italic> var. <jats:italic>pyramidalis</jats:italic> in 2017 and 2018. A dose-response experiment using a hand-held weed wiper was established with twenty treatments comprising two herbicides (glyphosate and hexazinone), uni- and bi-directional wiping methods, and five herbicide concentrations (6.25, 12.5, 25.0, 50.0 and 100% v/v basis). Data were collected 30 and 60 days after treatment (DAT). An ATV-mounted roto-type weed wiper experiment was established in a strip plot arrangement with mowing as the horizontal strip, the wiping method (uni-directional vs bi-directional) randomized as the vertical strip with three dosages of each herbicide for a total of 12 wiping treatments. Data were collected 35 and 90 DAT. The percent plant mortality was calculated using differences in pre- and post-treatment plant counts. Analysis of variance (ANOVA) and log-logistic linear regression were used to analyze the data. The dose-response experiment showed that <jats:italic>S. indicus</jats:italic> var. <jats:italic>pyramidalis</jats:italic> mortality increased with herbicide concentration and mortality was greater with the bi-directional wiping method compared to the uni-directional method. Treatments wiped bi-directionally with glyphosate at 70% v/v, hexazinone at 30% v/v and hexazinone at 60% v/v, resulted in <jats:italic>S. indicus</jats:italic> var. <jats:italic>pyramidalis</jats:italic> mortality ranging from 75 to 98% by 90 DAT across all locations. The ATV-mounted weed-wiper experiment showed that mowing prior to herbicide application with weed-wipers decreased the efficacy of both herbicides. Overall, both experiments indicate that <jats:italic>S. indicus</jats:italic> var. <jats:italic>pyramidalis</jats:italic> should be wiped bi-directionally using either glyphosate (70% v/v) or hexazinone (at least 30% v/v) to obtain satisfactory control. Further work should be conducted to determine if seasonality impacts the response of <jats:italic>S. indicus</jats:italic> var. <jats:italic>pyramidalis</jats:italic> to mowing and the application of these herbicides.","PeriodicalId":14470,"journal":{"name":"Invasive Plant Science and Management","volume":"43 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141191521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Injection-based approaches for controlling Douglas-fir (Pseudotsuga menziesii) invasion in conservation efforts of the Patagonian forest","authors":"M. Florencia Spalazzi, Tomás Milani, Cecilia I. Nuñez, Martin A. Nuñez, François P. Teste","doi":"10.1017/inp.2024.11","DOIUrl":"https://doi.org/10.1017/inp.2024.11","url":null,"abstract":"Invasion by nonnative woody species poses a major threat to the environment, biodiversity, and economies worldwide. Nahuel Huapi National Park in Argentina is a protected area for habitat conservation that harbors several invasive <jats:italic>Pinaceae</jats:italic> species, where Douglas-fir [<jats:italic>Pseudotsuga menziesii</jats:italic> (Mirb.) Franco] is one of the most aggressive and abundant conifer tree invaders. Management of invasions in protected areas must include efficient, easy to deploy, and cost-effective techniques, while reducing the impact on native ecosystems. Because the region has no control measures applied other than conventional felling, we analyzed the effectiveness of two systemic herbicides (glyphosate and aminopyralid + triclopyr) at two different concentrations, applied with the drill and fill method. We then quantified defoliation of <jats:italic>P. menziesii</jats:italic> trees after 6, 12, and 24 mo after application and performed an economic cost analysis to determine profitability. For the application, the trees were grouped into diameter at breast height classes and randomly assigned to one of the four treatments. Herbicide doses were adjusted according to tree size. We found that glyphosate at high concentrations completely defoliated 33% of the trees after 6 mo and 87% after 12 and 24 mo. Glyphosate at low concentrations defoliated almost 30% of the trees after 24 mo, most of which were smaller trees. The aminopyralid + triclopyr treatment did not produce significant defoliation at any of the tested concentrations. When compared with conventional felling, the drill and fill method was found to reduce removal costs by 98%. We observe that differences in costs are mainly due to dead trees that remain standing, decompose slowly, and do not generate costs associated with their removal and debris management. Drill and fill is a suitable method for treating scattered trees in a native forest community, with reduced environmental consequences compared with other removal techniques currently applied within conservation areas of the Patagonian forest.","PeriodicalId":14470,"journal":{"name":"Invasive Plant Science and Management","volume":"21 1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141169526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Excising the ghosts of invasions past: restoring native vegetation to soil infested with invasive swallow-worts","authors":"Emmett H. U. Snyder, Ian M. Jones, Melanie A. Sifton, Carla Timm, Courtney Stevens, Robert S. Bourchier, Sandy M. Smith","doi":"10.1017/inp.2024.7","DOIUrl":"https://doi.org/10.1017/inp.2024.7","url":null,"abstract":"Invasive plants can gain a foothold in new environments by manipulating soil conditions through allelopathy or through the disruption of associations between native plants and their mycorrhizal associates. The resulting changes in soil conditions can affect the recovery of habitats long after the invasive plant has been removed. We conducted a series of greenhouse experiments to examine the effects of soil conditioned by pale swallow-wort [<jats:italic>Vincetoxicum rossicum</jats:italic> (Kleopow) Barbarich; Apocynaceae], on the growth of native plants. Additionally, we tested the effects of aqueous extracts of common milkweed (<jats:italic>Asclepias syriaca</jats:italic> L.; Apocynaceae), a related plant with known allelopathic effects, on the regrowth of <jats:italic>V. rossicum</jats:italic> from transplanted root crowns. Soil from a 15-yr-old <jats:italic>V. rossicum</jats:italic> infestation reduced seedling emergence in <jats:italic>A. syriaca</jats:italic> as well as in <jats:italic>V. rossicum</jats:italic> itself. Conversely, the same soil had no effect on the growth of mature <jats:italic>A. syriaca</jats:italic> plants. Soil conditioned by <jats:italic>V. rossicum</jats:italic> growth in the greenhouse had no effect on the biomass and percentage cover generated by two restoration seed mixes. Soil conditioned by <jats:italic>A. syriaca</jats:italic>, however, yielded lower biomass and percentage cover from both seed mixes. In contrast to the allelopathic effects of <jats:italic>A. syriaca</jats:italic> on seedlings, aqueous extracts of <jats:italic>A. syriaca</jats:italic> increased aboveground plant growth in <jats:italic>V. rossicum</jats:italic>. Our results suggest that the effects of <jats:italic>V. rossicum</jats:italic>–conditioned soil on native plants are concentrated at the seedling establishment phase. Additionally, the use of diverse native seed mixes shows great potential for restoring productivity to ecosystems affected by <jats:italic>V. rossicum</jats:italic>.","PeriodicalId":14470,"journal":{"name":"Invasive Plant Science and Management","volume":"28 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140941239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isolation and reinoculation of a gall-inducing fungus in the invasive Brazilian peppertree (Schinus terebinthifolia) in Florida","authors":"Dale A. Halbritter, Min B. Rayamajhi, Paul Madeira, Jorge G. Leidi, Telmah Telmadarrehei, Carey Minteer","doi":"10.1017/inp.2024.3","DOIUrl":"https://doi.org/10.1017/inp.2024.3","url":null,"abstract":"Stem galls and witch’s broom–like growths are locally abundant on the highly invasive Brazilian peppertree (<jats:italic>Schinus terebinthifolia</jats:italic>) at field sites in southern Florida where a thrips biological control agent (<jats:italic>Pseudophilothrips ichini</jats:italic>) is being released to reduce the invasive potential of the plant. Galls have also been observed on potted plants in nursery stock grown to feed laboratory colonies of the agent. Herein, our objective was to isolate and identify the causal agent of the galls and assess its ability to induce galls in naive plants. We obtained stem galls from both field- and nursery-grown plants, aseptically isolated a fungus in acidic potato dextrose agar, and purified fungal colonies. Stems of potted naive saplings were wound-inoculated with purified hyphal fragments from the purified colonies, which readily induced galls like those observed in the field and nursery. Simultaneous molecular analysis of the fungal DNA obtained from the galls of field and nursery plants, experimentally induced galls, and fungal colony isolates identified this gall-inducing fungus as <jats:italic>Cophinforma</jats:italic> sp. We demonstrated that this <jats:italic>Cophinforma</jats:italic> sp. can infect <jats:italic>S. terebinthifolia</jats:italic> stems via mechanical wounds and induce visibly discernible stem galls in saplings within 3 mo. This will serve as a model for galled plant production for assessing the impacts of the gall-inducing fungus on <jats:italic>S. terebinthifolia</jats:italic>, with potential for further study to investigate interactions between the thrips and this naturalized fungus, which may synergistically and/or additively enhance <jats:italic>S. terebinthifolia</jats:italic> management efficacy.","PeriodicalId":14470,"journal":{"name":"Invasive Plant Science and Management","volume":"94 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140629754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unraveling the influence of environmental factors on fireweed (Senecio madagascariensis) germination and its management implications","authors":"Virender Singh Hooda, Bhagirath Singh Chauhan","doi":"10.1017/inp.2024.8","DOIUrl":"https://doi.org/10.1017/inp.2024.8","url":null,"abstract":"Fireweed (<jats:italic>Senecio madagascariensis</jats:italic> Poir.) has invaded and colonized numerous habitats in the coastal areas of southeastern Australia and is a major weed in cultivated lands as well as in poorly grassed, neglected, and highly grazed pastures. To examine the seed germination ecology of two populations (Felton and Gatton) of <jats:italic>S. madagascariensis</jats:italic>, experiments were conducted in the laboratory and screenhouse. The germination of both populations increased as the alternating temperatures increased from the coolest temperatures (15/5 C) to warmer temperatures (25/15 C). However, the highest temperature regime (35/25 C) resulted in the lowest germination rates. The Gatton population exhibited greater tolerance to higher temperatures, resulting in significantly higher germination (2.4 times) than the Felton population at the highest alternating temperature of 35/25 C. Compared to the Felton population, the Gatton population demonstrated higher tolerance to salt and water stress. In comparison to alternating light and dark periods (12 h each) (97-98%), the germination of both populations of <jats:italic>S. madagascariensis</jats:italic> was significantly reduced under complete darkness (24 h) (33-39%). A screenhouse seed burial depth experiment revealed similar emergence of <jats:italic>S. madagascariensis</jats:italic> seedlings between the populations. The maximum emergence (60%) was observed for seeds placed at the soil surface, followed by a dramatic decline in seedling emergence with an increase in depth. No seedlings emerged from a burial depth of 4 cm. With the addition of wheat crop residue to the soil surface at rates comparable to 4 to 8 Mg ha<jats:sup>-1</jats:sup>, seedling emergence of <jats:italic>S. madagascariensis</jats:italic> decreased significantly. Information acquired from this study could be utilized to manage and develop effective weed management strategies for controlling <jats:italic>S. madagascariensis</jats:italic> in different agroecological conditions.","PeriodicalId":14470,"journal":{"name":"Invasive Plant Science and Management","volume":"20 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140154620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fall or spring aminopyralid applications control Taeniatherum caput-medusae","authors":"Lisa C. Jones, Cody Beckley, Corey V. Ransom, Timothy S. Prather","doi":"10.1017/inp.2024.6","DOIUrl":"https://doi.org/10.1017/inp.2024.6","url":null,"abstract":"<jats:italic>Taeniatherum caput-medusae</jats:italic> (L.) Nevski is an invasive winter annual grass of western North American grasslands and rangelands that negatively impacts forage production, wildlife habitat, and ecosystem processes. Growth regulator herbicides, such as aminopyralid, applied in spring reduce invasive annual grass seed viability in greenhouse and California annual grassland experiments. Beginning in fall 2017, we tested combinations of sequential fall (preemergence, PRE) and spring (postemergence, POST) aminopyralid applications at low (103 g ae ha<jats:sup>-1</jats:sup>) and high (206 g ae ha<jats:sup>-1</jats:sup>) rates at two ecologically distinct sites in the Intermountain West. PRE and POST aminopyralid applications at low and high rates controlled <jats:italic>T. caput-medusae</jats:italic> by 76-100% the second summer after study initiation. At the Utah site (which is warmer, drier, and more degraded than the Idaho site), the high rate resulted in better control. The first summer, POST aminopyralid applications at low and high rates reduced seed viability 47-91% compared to nontreated seeds, with the greatest reductions seen in Utah, which was experiencing drought. Across study sites, reduced <jats:italic>T. caput-medusae</jats:italic> germination in one year was linked to improved control the following year. The Idaho site also had desirable perennial grasses on which we investigated non-target effects. In general, there was a correlation between high <jats:italic>T. caput-medusae</jats:italic> control and higher perennial grass cover, indicating that successful control can make desirable perennial grasses more vigorous in this system. The option of a spring aminopyralid application increases the management window for controlling invasive annual grasses by decreasing seed viability, thereby depleting short-lived seed banks.","PeriodicalId":14470,"journal":{"name":"Invasive Plant Science and Management","volume":"5 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140005816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Population structure of three invasive congeneric teasel (Dipsacus) species","authors":"John F. Gaskin, Natalie West, Brian G. Rector","doi":"10.1017/inp.2024.5","DOIUrl":"https://doi.org/10.1017/inp.2024.5","url":null,"abstract":"Three species of the Old World genus <jats:italic>Dipsacus</jats:italic> L. are considered invasive in the Americas, yet they may differ in how they spread, reproduce, and in genetic diversity. Differences in invasion method may suggest that different management techniques are needed for each species. We performed genetic analyses on 572 plants in 69 populations from the USA, Argentina, and Eurasia with the goals of analyzing taxonomy, diversity, mode of reproduction, population structure and founder effect of each of these species’ invasions, as well as looking for evidence of recent or ongoing hybridization. We found <jats:italic>D. sativus</jats:italic> to be lowest in diversity and possibly relying on self-pollination more than the other species, <jats:italic>D. fullonum</jats:italic> and <jats:italic>D. laciniatus</jats:italic>. We found no evidence of hybridization within the invasions and no support for <jats:italic>D. sativus</jats:italic> as a subspecies of <jats:italic>D. fullonum</jats:italic>. The closest genetic matches of <jats:italic>D. fullonum</jats:italic> from USA to the native range were with Hungary and Spain, while the closest match for <jats:italic>D. fullonum</jats:italic> between Argentina and the native range was with Spain. <jats:italic>Dipsacus laciniatus</jats:italic> from the USA most closely matched with samples from Russia. Population structure information regarding these three weedy <jats:italic>Dipsacus</jats:italic> species can help us understand their invasive processes as well as give insight into their management and the development of a biological control program.","PeriodicalId":14470,"journal":{"name":"Invasive Plant Science and Management","volume":"79 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140005935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrilla verticillata subsp. lithuanica: discovery and establishment outside of the Connecticut River","authors":"Jeremiah R. Foley, Summer E. Stebbins, Riley Doherty, Nicholas P. Tippery, Gregory J. Bugbee","doi":"10.1017/inp.2024.4","DOIUrl":"https://doi.org/10.1017/inp.2024.4","url":null,"abstract":"Hydrilla [<jats:italic>Hydrilla verticillata</jats:italic> (L.f.) Royle], an invasive aquatic weed, has had a rich introduction history into the United States with multiple subspecies being introduced since the 1960’s. The most recent occurred prior to 2016, when northern hydrilla (<jats:italic>Hydrilla verticillata</jats:italic> subsp. <jats:italic>lithuanica</jats:italic>) was discovered in the Connecticut River. By 2021, following a three-year survey from Agawam, MA to the Long Island Sound by the Connecticut Agricultural Experiment Station Office of Aquatic Invasive Species, <jats:italic>H. verticillata</jats:italic> subsp. <jats:italic>lithuanica</jats:italic> was found in over 113 km of the river, occupying 344 hectares. Since this survey, there has been concern that <jats:italic>H. verticillata</jats:italic> subsp. <jats:italic>lithuanica</jats:italic> would spread to nearby waterbodies and have a significant negative impact. Here we report the first documented spread and establishment of <jats:italic>H. verticillata</jats:italic> subsp. <jats:italic>lithuanica</jats:italic> from the Connecticut River to five waterbodies in Connecticut and one in Massachusetts. Of the total eight sites where <jats:italic>H. verticillata</jats:italic> observations were made, 75% (n=6) were confirmed to be <jats:italic>H. verticillata</jats:italic> subsp. <jats:italic>lithuanica</jats:italic> and 25% (n=2) to be wandering hydrilla (<jats:italic>Hydrilla. verticillata</jats:italic> subsp. <jats:italic>peregrina</jats:italic>). Except for one site, all six locations infested with <jats:italic>H. verticillata</jats:italic> subsp. <jats:italic>lithuanica</jats:italic> provide watercraft access through public or private boat ramps. The authors also postulate on the mechanisms facilitating the spread and establishment of this subspecies.","PeriodicalId":14470,"journal":{"name":"Invasive Plant Science and Management","volume":"4 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139771519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term interactive impacts of the invasive shrub, Lonicera maackii, and white-tailed deer, Odocoileus virginianus, on a deciduous forest understory","authors":"Marco U. Donoso, Hanna Leonard, David L. Gorchov","doi":"10.1017/inp.2024.2","DOIUrl":"https://doi.org/10.1017/inp.2024.2","url":null,"abstract":"White-tailed deer and invasive plants affect forest understories, but few studies have investigated their interaction. We investigated long-term (11-year) effects of excluding deer and removing the invasive shrub, <jats:italic>Lonicera maackii</jats:italic>, on plants in southwest Ohio. Deer exclusion enhanced tree seedling richness and density, but reduced annual and bare ground cover. Vine density was reduced by <jats:italic>Lonicera</jats:italic>, especially where deer were excluded. Seedlings of several tree species, the invasive shrub <jats:italic>Euonymous alatus</jats:italic>, and the invasive vine <jats:italic>E. fortunei</jats:italic>, were indicator species of the deer exclosure x <jats:italic>Lonicera</jats:italic> removal treatment combination. The effect of deer on cover of native species depended on <jats:italic>Lonicera</jats:italic> treatment: where shrubs were removed, cover was higher where deer were excluded, but where shrubs were present, cover was higher where deer had access. We attribute these interactions to the reduced growth of, and shading by, <jats:italic>Lonicera</jats:italic> where deer had access and browsed this invasive shrub. Some of these effects were evident in the first 6 years, but are now larger. Other effects were not evident in the earlier evaluation. These findings inform management of areas with high densities of deer and invasive shrubs palatable to deer. Control only of invasive shrubs will reduce native cover and not improve tree regeneration. Managing only deer will increase woody plants but reduce native cover. Management of both stressors is needed to promote tree regeneration and restoration of plant communities.","PeriodicalId":14470,"journal":{"name":"Invasive Plant Science and Management","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139586788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Competition reduces structural defense in an invasive thistle in the field","authors":"Rachel Lamb, Joseph Keller, Katriona Shea","doi":"10.1017/inp.2023.33","DOIUrl":"https://doi.org/10.1017/inp.2023.33","url":null,"abstract":"Invasive thistles reduce the productivity of pastures and rangelands because their structural defenses make them unpalatable to grazing livestock. However, plants potentially alter their growth patterns, including their allocation of resources to defense, in response to the presence of competing vegetation. Understanding the effects of competition on the structural defense of problematic pasture weeds can inform management plans that reduce the economic harm caused by these pests. We grew <jats:italic>Carduus nutans</jats:italic> L. in a fully crossed factorial field experiment in a single abandoned pasture in 2017 with two experimental factors: the level of thistle infestation (1 thistle or 5, resulting in densities of 4 or 20 plants m<jats:sup>-2</jats:sup>) and the presence or absence of grazing (simulated by weekly trimming of competing vegetation). We assessed the effects of treatments on defense by counting prickles &gt;3 mm long on leaves. Our analysis included leaf age and leaf size as covariates. Competition reduced the number of prickles present on leaves. Regression analysis showed that an increase from, for example, 50 g to 200 g of competing vegetation within 50 x 50 cm study plots reduced the expected average number of prickles on intermediate-aged leaves with average length 25.5 cm by 76.9 prickles/leaf, or 41%. This pattern was similar for leaves of all ages, though the oldest leaves generally had fewer prickles than younger leaves. We did not observe differences in defense structures between plants neighbored by conspecifics and those neighbored by other competitors. <jats:italic>Carduus nutans</jats:italic> has been previously managed using high densities of grazers, and this practice may be more likely to damage less-defended individuals such as those we observed in our treatments with competition. This finding suggests that maintaining competition in pastures may increase <jats:italic>C. nutans</jats:italic>’ vulnerability to grazing.","PeriodicalId":14470,"journal":{"name":"Invasive Plant Science and Management","volume":"38 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139421763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}