WorldWideScience

Sample records for nonnative invasive plant

  1. Wildland fire in ecosystems: fire and nonnative invasive plants

    Science.gov (United States)

    Kristin Zouhar; Jane Kapler Smith; Steve Sutherland; Matthew L. Brooks

    2008-01-01

    This state-of-knowledge review of information on relationships between wildland fire and nonnative invasive plants can assist fire managers and other land managers concerned with prevention, detection, and eradication or control of nonnative invasive plants. The 16 chapters in this volume synthesize ecological and botanical principles regarding relationships between...

  2. Non-native plant invasions of United States National parks

    Science.gov (United States)

    Allen, J.A.; Brown, C.S.; Stohlgren, T.J.

    2009-01-01

    The United States National Park Service was created to protect and make accessible to the public the nation's most precious natural resources and cultural features for present and future generations. However, this heritage is threatened by the invasion of non-native plants, animals, and pathogens. To evaluate the scope of invasions, the USNPS has inventoried non-native plant species in the 216 parks that have significant natural resources, documenting the identity of non-native species. We investigated relationships among non-native plant species richness, the number of threatened and endangered plant species, native species richness, latitude, elevation, park area and park corridors and vectors. Parks with many threatened and endangered plants and high native plant species richness also had high non-native plant species richness. Non-native plant species richness was correlated with number of visitors and kilometers of backcountry trails and rivers. In addition, this work reveals patterns that can be further explored empirically to understand the underlying mechanisms. ?? Springer Science+Business Media B.V. 2008.

  3. Nonnative invasive plants: Maintaining biotic and soceioeconomic integrity along the urban-rural-natural gradient

    Science.gov (United States)

    Cynthia D. Huebner; David J. Nowak; Richard V. Pouyat; Allison R. Bodine

    2012-01-01

    In this chapter, we evaluate nonnative invasive plant species of the urban-rural-natural area gradient in order to reduce negative impacts of invasive plants on native species and ecosystems. This evaluation includes addressing (i) the concept of urban areas as the primary source of invasive plant species and characteristics of urban nonnative plants, including their...

  4. Non-native earthworms promote plant invasion by ingesting seeds and modifying soil properties

    OpenAIRE

    Clause, J.; Forey, E.; Lortie, C. J.; Lambert, A. M.; Barot, Sébastien

    2015-01-01

    Earthworms can have strong direct effects on plant communities through consumption and digestion of seeds, however it is unclear how earthworms may influence the relative abundance and composition of plant communities invaded by non-native species. In this study, earthworms, seed banks, and the standing vegetation were sampled in a grassland of central California. Our objectives were i) to examine whether the abundances of non-native, invasive earthworm species and non-native grassland plant ...

  5. The Role of Fuel Breaks in the Invasion of Nonnative Plants

    Science.gov (United States)

    Merriam, Kyle E.; Keeley, Jon E.; Beyers, Jan L.

    2007-01-01

    Executive Summary Fuel reduction projects have become an increasingly important component of state and federal fuels management programs. However, an unintended result of some pre-fire fuel manipulation projects may be the introduction of nonnative invasive plants. The establishment of nonnative plants within fuel breaks is a serious concern because the presence of invasive species in areas treated to reduce fuels could make adjacent wildland areas more susceptible to invasion, particularly following widespread disturbances such as fires. This report presents the results of a research project investigating the relationship between fuel reduction treatments and the invasion of nonnative plants. Throughout the rest of this document, we will collectively refer to these treatments as fuel breaks, although we sampled a range of fuel breaks described variously as fuel breaks, shaded fuel breaks, defensible fuel reduction zones, defensible fuel profile zones, fuel reduction projects, fuel management zones, wildfire protection zones, and community protection zones.

  6. Non-native earthworms promote plant invasion by ingesting seeds and modifying soil properties

    Science.gov (United States)

    Clause, Julia; Forey, Estelle; Lortie, Christopher J.; Lambert, Adam M.; Barot, Sébastien

    2015-04-01

    Earthworms can have strong direct effects on plant communities through consumption and digestion of seeds, however it is unclear how earthworms may influence the relative abundance and composition of plant communities invaded by non-native species. In this study, earthworms, seed banks, and the standing vegetation were sampled in a grassland of central California. Our objectives were i) to examine whether the abundances of non-native, invasive earthworm species and non-native grassland plant species are correlated, and ii) to test whether seed ingestion by these worms alters the soil seed bank by evaluating the composition of seeds in casts relative to uningested soil. Sampling locations were selected based on historical land-use practices, including presence or absence of tilling, and revegetation by seed using Phalaris aquatica. Only non-native earthworm species were found, dominated by the invasive European species Aporrectodea trapezoides. Earthworm abundance was significantly higher in the grassland blocks dominated by non-native plant species, and these sites had higher carbon and moisture contents. Earthworm abundance was also positively related to increased emergence of non-native seedlings, but had no effect on that of native seedlings. Plant species richness and total seedling emergence were higher in casts than in uningested soils. This study suggests that there is a potential effect of non-native earthworms in promoting non-native and likely invasive plant species within grasslands, due to seed-plant-earthworm interactions via soil modification or to seed ingestion by earthworms and subsequent cast effects on grassland dynamics. This study supports a growing body of literature for earthworms as ecosystem engineers but highlights the relative importance of considering non-native-native interactions with the associated plant community.

  7. Regional patterns of major nonnative invasive plants and associated factors in upper Midwest forests

    Science.gov (United States)

    Zhaofei Fan; W. Keith Moser; Mark H. Hansen; Mark D. Nelson

    2013-01-01

    Nonnative invasive plants (IPs) are rapidly spreading into natural ecosystems (e.g., forests and grasslands). Potential threats of IP invasion into natural ecosystems include biodiversity loss, structural and environmental change, habitat degradation, and economic losses. The Upper Midwest of the United States encompasses the states of Illinois, Indiana, Iowa, Michigan...

  8. Are native songbird populations affected by non-native plant invasion?

    Science.gov (United States)

    Amanda M. Conover; Christopher K. Williams; Vincent. D' Amico

    2011-01-01

    Development into forested areas is occurring rapidly across the United States, and many of the remnant forests within suburban landscapes are being fragmented into smaller patches, impacting the quality of this habitat for avian species. An ecological effect linked to forest fragmentation is the invasion of non-native plants into the ecosystem.

  9. The influence of ungulates on non-native plant invasions in forests and rangelands: a review.

    Science.gov (United States)

    Catherine G. Parks; Michael J. Wisdom; John G. Kie

    2005-01-01

    Herbivory by wild and domestic ungulates can strongly influence vegetation composition and productivity in forest and range ecosystems. However, the role of ungulates as contributors to the establishment and spread of non-native invasive plants is not well known. Ungulates spread seeds through endozoochory (passing through an animal's digestive tract) or...

  10. Competitive effects of non-native plants are lowest in native plant communities that are most vulnerable to invasion

    Science.gov (United States)

    J.Stephen Brewer; W. Chase Bailey

    2014-01-01

    Despite widespread acknowledgment that disturbance favors invasion, a hypothesis that has received little attention is whether non-native invaders have greater competitive effects on native plants in undisturbed habitats than in disturbed habitats. This hypothesis derives from the assumption that competitive interactions are more persistent in habitats that have not...

  11. Susceptibility of burned black spruce (Picea mariana) forests to non-native plant invasions in interior Alaska

    Science.gov (United States)

    Katie V. Spellman; Christa P.H. Mulder; Teresa N. Hollingsworth

    2014-01-01

    As climate rapidly warms at high-latitudes, the boreal forest faces the simultaneous threats of increasing invasive plant abundances and increasing area burned by wildfire. Highly flammable and widespread black spruce (Picea mariana) forest represents a boreal habitat that may be increasingly susceptible to non-native plant invasion. This study assess the role of burn...

  12. Non-Native Plant Invasion along Elevation and Canopy Closure Gradients in a Middle Rocky Mountain Ecosystem.

    Directory of Open Access Journals (Sweden)

    Joshua P Averett

    Full Text Available Mountain environments are currently among the ecosystems least invaded by non-native species; however, mountains are increasingly under threat of non-native plant invasion. The slow pace of exotic plant invasions in mountain ecosystems is likely due to a combination of low anthropogenic disturbances, low propagule supply, and extreme/steep environmental gradients. The importance of any one of these factors is debated and likely ecosystem dependent. We evaluated the importance of various correlates of plant invasions in the Wallowa Mountain Range of northeastern Oregon and explored whether non-native species distributions differed from native species along an elevation gradient. Vascular plant communities were sampled in summer 2012 along three mountain roads. Transects (n = 20 were evenly stratified by elevation (~70 m intervals along each road. Vascular plant species abundances and environmental parameters were measured. We used indicator species analysis to identify habitat affinities for non-native species. Plots were ordinated in species space, joint plots and non-parametric multiplicative regression were used to relate species and community variation to environmental variables. Non-native species richness decreased continuously with increasing elevation. In contrast, native species richness displayed a unimodal distribution with maximum richness occurring at mid-elevations. Species composition was strongly related to elevation and canopy openness. Overlays of trait and environmental factors onto non-metric multidimensional ordinations identified the montane-subalpine community transition and over-story canopy closure exceeding 60% as potential barriers to non-native species establishment. Unlike native species, non-native species showed little evidence for high-elevation or closed-canopy specialization. These data suggest that non-native plants currently found in the Wallowa Mountains are dependent on open canopies and disturbance for

  13. Non-Native Plant Invasion along Elevation and Canopy Closure Gradients in a Middle Rocky Mountain Ecosystem.

    Science.gov (United States)

    Averett, Joshua P; McCune, Bruce; Parks, Catherine G; Naylor, Bridgett J; DelCurto, Tim; Mata-González, Ricardo

    2016-01-01

    Mountain environments are currently among the ecosystems least invaded by non-native species; however, mountains are increasingly under threat of non-native plant invasion. The slow pace of exotic plant invasions in mountain ecosystems is likely due to a combination of low anthropogenic disturbances, low propagule supply, and extreme/steep environmental gradients. The importance of any one of these factors is debated and likely ecosystem dependent. We evaluated the importance of various correlates of plant invasions in the Wallowa Mountain Range of northeastern Oregon and explored whether non-native species distributions differed from native species along an elevation gradient. Vascular plant communities were sampled in summer 2012 along three mountain roads. Transects (n = 20) were evenly stratified by elevation (~70 m intervals) along each road. Vascular plant species abundances and environmental parameters were measured. We used indicator species analysis to identify habitat affinities for non-native species. Plots were ordinated in species space, joint plots and non-parametric multiplicative regression were used to relate species and community variation to environmental variables. Non-native species richness decreased continuously with increasing elevation. In contrast, native species richness displayed a unimodal distribution with maximum richness occurring at mid-elevations. Species composition was strongly related to elevation and canopy openness. Overlays of trait and environmental factors onto non-metric multidimensional ordinations identified the montane-subalpine community transition and over-story canopy closure exceeding 60% as potential barriers to non-native species establishment. Unlike native species, non-native species showed little evidence for high-elevation or closed-canopy specialization. These data suggest that non-native plants currently found in the Wallowa Mountains are dependent on open canopies and disturbance for establishment in low

  14. Fleshy fruit removal and nutritional composition of winter-fruiting plants: a comparison of non-native invasive and native species

    Science.gov (United States)

    Cathryn H. Greenberg; Scott T. Walter

    2010-01-01

    Invasive, non-native plants threaten forest ecosystems by reducing native plant species richness and potentially altering ecosystem processes. Seed dispersal is critical for successful invasion and range expansion by non-native plants; dispersal is likely to be enhanced if they can successfully compete with native plants for disperser services. Fruit production by non-...

  15. Assessment of Nonnative Invasive Plants in the DOE Oak Ridge National Environmental Research Park

    Energy Technology Data Exchange (ETDEWEB)

    Drake, S.J.

    2002-11-05

    The Department of Energy (DOE) National Environmental Research Park at Oak Ridge, Tennessee, is composed of second-growth forest stands characteristic of much of the eastern deciduous forest of the Ridge and Valley Province of Tennessee. Human use of natural ecosystems in this region has facilitated the establishment of at least 167 nonnative, invasive plant species on the Research Park. Our objective was to assess the distribution, abundance, impact, and potential for control of the 18 most abundant invasive species on the Research Park. In 2000, field surveys were conducted of 16 management areas on the Research Park (14 Natural Areas, 1 Reference Area, and Walker Branch Watershed) and the Research Park as a whole to acquire qualitative and quantitative data on the distribution and abundance of these taxa. Data from the surveys were used to rank the relative importance of these species using the ''Alien Plant Ranking System, Version 5.1'' developed by the U.S. Geological Survey. Microstegium (Microstegium vimineum) was ranked highest, or most problematic, for the entire Research Park because of its potential impact on natural systems, its tendency to become a management problem, and how difficult it is to control. Microstegium was present in 12 of the 16 individual sites surveyed; when present, it consistently ranked as the most problematic invasive species, particularly in terms of its potential impact on natural systems. Japanese honeysuckle (Lonicera japonica) and Chinese privet (Ligustrum sinense) were the second- and third-most problematic plant species on the Research Park; these two species were present in 12 and 9 of the 16 sites surveyed, respectively, and often ranked second- or third-most problematic. Other nonnative, invasive species, in decreasing rank order, included kudzu (Pueraria montma), multiflora rose (Rosa multiflora), Chinese lespedeza (Lespedeza cuneara), and other species representing a variety of life forms and growth

  16. Status and management of non-native plant invasion in three of the largest national parks in the United States

    Directory of Open Access Journals (Sweden)

    Scott Abella

    2015-06-01

    Full Text Available Globally, invasion by non-native plants threatens resources that nature reserves are designated to protect. We assessed the status of non-native plant invasion on 1,662, 0.1-ha plots in Death Valley National Park, Mojave National Preserve, and Lake Mead National Recreation Area. These parks comprise 2.5 million ha, 23% of the national park land in the contiguous USA. At least one non-native species inhabited 82% of plots. Thirty-one percent of plots contained one non-native species, 30% two, 17% three, and 4% four to ten non-native species. Red brome (Bromus rubens, an ‘ecosystem engineer’ that alters fire regimes, was most widespread, infesting 60% of plots. By identifying frequency of species through this assessment, early detection and treatment can target infrequent species or minimally invaded sites, while containment strategies could focus on established invaders. We further compared two existing systems for prioritizing species for management and found that a third of species on plots had no rankings available. Moreover, rankings did not always agree between ranking systems for species that were ranked. Presence of multiple non-native species complicates treatment, and while we found that 40% of plots contained both forb and grass invaders, exploiting accelerated phenology of non-natives (compared to native annuals might help manage multi-species invasions. Large sizes of these parks and scale of invasion are formidable challenges for management. Yet, precisely because of their size, these reserves represent opportunities to conserve large landscapes of native species by managing non-native plant invasions.

  17. Nonnative invasive plants in the Penobscot Experimental Forest in Maine, USA: influence of site, silviculture, and land use history

    Science.gov (United States)

    Elizabeth Olson; Laura S. Kenefic; Alison C. Dibble; John C. Brissette

    2011-01-01

    We investigated the occurrence of nonnative invasive plants on approximately 175 ha comprising a long-term, 60-year-old U.S. Forest Service silvicultural experiment and old-field stands in the Penobscot Experimental Forest (PEF) in central Maine. Stands in the silvicultural experiment were never cleared for agriculture, but have been repeatedly partially cut. Our...

  18. Response of six non-native invasive plant species to wildfires in the northern Rocky Mountains, USA

    Science.gov (United States)

    Dennis E. Ferguson; Christine L. Craig

    2010-01-01

    This paper presents early results on the response of six non-native invasive plant species to eight wildfires on six National Forests (NFs) in the northern Rocky Mountains, USA. Stratified random sampling was used to choose 224 stands based on burn severity, habitat type series, slope steepness, stand height, and stand density. Data for this report are from 219 stands...

  19. Occurrence and spread of nonnative invasive plants in stands treated with fire and/or mechanical treatments in the upper piedmont of South Carolina

    Science.gov (United States)

    Ross J. Phillips; Thomas A. Waldrop; Aaron D. Stottlemyer

    2013-01-01

    Increasing numbers of nonnative invasive plant species and the expansion of existing nonnative plant populations provide challenges for land managers trying to achieve commercial and restoration goals. Some methods used to achieve these goals, e.g., prescribed fire and mechanical treatments, may result in disturbances that promote the establishment and spread of...

  20. Prevention, early detection and containment of invasive, nonnative plants in the Hawaiian Islands: current efforts and needs

    Science.gov (United States)

    Christoph Kueffer,; Loope, Lloyd

    2009-01-01

    Introduction: Invasive, non-native plants (or environmental weeds) have long been recognized as a major threat to the native biodiversity of oceanic islands (Cronk & Fuller, 1995; Denslow, 2003). Globally, several hundred non-native plant species have been reported to have major impacts on natural areas on oceanic islands (Kueffer et al., 2009). In Hawaii, at least some 50 non-native plant species reach dominance in natural areas (Kueffer et al., 2009) and many of them are known to impact ecosystem processes or biodiversity. One example is the invasive Australian tree fern (Cyathea cooperi), which has been shown to be very efficient at utilizing soil nitrogen and can grow six times as rapidly in height, maintain four times more fronds, and produce significantly more fertile fronds per month than the native Hawaiian endemic tree ferns, Cibotium spp. (Durand & Goldstein, 2001a, b). Additionally, while native tree ferns provide an ideal substrate for epiphytic growth of many understory ferns and flowering plants, the Australian tree fern has the effect of impoverishing the understory and failing to support an abundance of native epiphytes (Medeiros & Loope, 1993). Other notorious examples of invasive plant species problematic for biodiversity and ecosystem processes in Hawaii include miconia (Miconia calvescens), strawberry guava (Psidium cattleianum), albizia (Falcataria moluccana), firetree (Morella faya), clidemia (Clidemia hirta), kahili ginger (Hedychium gardnerianum), and fountain grass (Pennisetum setaceum), to name just a few. Fireweed (Senecio madagascariensis) is a recent example of a seriously problematic invasive species for Hawaii’s agriculture and is damaging certain high-elevations native ecosystems as well.

  1. Impacts of invasive nonnative plant species on the rare forest herb Scutellaria montana

    Science.gov (United States)

    Sikkema, Jordan J.; Boyd, Jennifer N.

    2015-11-01

    Invasive plant species and overabundant herbivore populations have the potential to significantly impact rare plant species given their increased risk for local extirpation and extinction. We used interacting invasive species removal and grazer exclusion treatments replicated across two locations in an occurrence of rare Scutellaria montana (large-flowered skullcap) in Chattanooga, Tennessee, USA, to assess: 1) competition by invasive Ligustrum sinense (Chinese privet) and Lonicera japonica (Japanese honeysuckle) and 2) the role of invasive species in mediating Oedocoilus virginianus (white-tailed deer) grazing of S. montana. Contrary to our hypothesis that invasive species presence would suppress S. montana directly via competition, S. montana individuals experienced a seasonal increase in stem height when invasive species were intact but not when invasive species were removed. Marginally significant results indicated that invasive species may afford S. montana protection from grazers, and we suggest that invasive species also could protect S. montana from smaller herbivores and/or positively influence abiotic conditions. In contrast to growth responses, S. montana individuals protected from O. virginianus exhibited a decrease in flowering between seasons relative to unprotected plants, but invasive species did not affect this variable. Although it has been suggested that invasive plant species may negatively influence S. montana growth and fecundity, our findings do not support related concerns. As such, we suggest that invasive species eradication efforts in S. montana habitat could be more detrimental than positive due to associated disturbance. However, the low level of invasion of our study site may not be representative of potential interference in more heavily infested habitat.

  2. Impacts of Climate Variability on Non-native Plant Invasion in the Western U.S.

    Science.gov (United States)

    Bradley, B. A.

    2006-12-01

    Plant invasions are changing ecosystem structure and function throughout the United States. In many areas of the west, invasive species such as tamarisk (Tamarix spp.), cheatgrass (Bromus tectorum), and yellow starthistle (Centaurea solstitialis) dominate landscapes. Expansion of these species is occurring at a staggering rate, and invasion rates may change in the future as native ecosystems become more or less susceptible to invasion because of changes in climate. For example, evidence suggests that some plant invaders are favored under increased ambient CO2 levels, potentially leading to increased invasion with continued greenhouse gas emissions. In this work, I predict how western invasive plant species may also be affected by changes in climate variability. According to IPCC reports, rising ocean temperatures may change the frequency and intensity of El Niño events, potentially resulting in wetter El Niño years and/or more extreme and lengthier drought. In semi-arid systems, changing frequency or magnitude of extreme weather events may further shift the competitive balance between native and invasive species. For example, cheatgrass and yellow starthistle, both annual invaders, display high inter-annual variability in response to water availability. As a result, plants are larger and produce more seeds than native competitors during extreme wet years. This phenological response is so strong in cheatgrass communities that it can be observed in regional satellite records. Further, dense cheatgrass growth leads to a secondary feedback in the form of wildfire; higher density cheatgrass increases fire frequency in shrublands and enables further cheatgrass colonization. In this work, I synthesize knowledge of invasive plant phenological response under different climate conditions, drawing on information gathered through geographical mapping efforts at state or regional levels by university and agency researchers. Using the ranges of climate tolerance from current

  3. Changes in the Pincate Reserve ecosystems: Invasion of non-native plants

    Science.gov (United States)

    Denise Z. Avila-Jimenez

    2005-01-01

    Over the years, humans have modified the Sonoran Desert by introducing invasive plants that prosper in disturbed and non-disturbed habitats. These invaders modify the dynamics and structure of populations and the composition of communities, which in turn can result in radical changes in wildlife habitat. The natural landscape of the Sonoran Desert is characterized by...

  4. Using GIS to integrate FIA and remotely sensed data to estimate the invasibility of major forest types by non-native invasive plants in the Upper Midwest, USA

    Science.gov (United States)

    Zhaofei Fan; W. Keith Moser; Michael K. Crosby; Weiming Yu

    2012-01-01

    Non-native invasive plants (NNIP) are rapidly spreading into natural ecosystems such as forests in the Upper Midwest. Using the strategic inventory data from the 2005-2006 U.S. Department of Agriculture, Forest Service’s Forest Inventory and Analysis (FIA) program and forest land cover data, we estimated the regional-invasibility patterns of NNIPs for major...

  5.  Invasibility of three major non-native invasive shrubs and associated factors in Upper Midwest U.S. forest lands

    Science.gov (United States)

    W. Keith Moser; Zhaofei Fan; Mark H. Hansen; Michael K. Crosby; Shirley X. Fan

    2016-01-01

    We used non-native invasive plant data from the US Forest Service’s Forest Inventory and Analysis (FIA) program, spatial statistical methods, and the space (cover class)-for-time approach to quantify the invasion potential and success ("invasibility") of three major invasive shrubs (multiflora rose, non-native bush honeysuckles, and common buckthorn...

  6. Exotic invasive plants

    Science.gov (United States)

    Carolyn Hull Sieg; Barbara G. Phillips; Laura P. Moser

    2003-01-01

    Ecosystems worldwide are threatened by nonnative plant invasions that can cause undesirable, irreversible changes. They can displace native plants and animals, out-cross with native flora, alter nutrient cycling and other ecosystem functions, and even change an ecosystem's flammability (Walker and Smith 1997). After habitat loss, the spread of exotic species is...

  7. Invasive plants in 21st Century landscapes.

    Science.gov (United States)

    Valerie. Rapp

    2005-01-01

    A plant species is defined as invasive if it is nonnative to the ecosystem under consideration, and if it causes or is likely to cause economic or environmental harm or harm to human health. Nonnative plant invasions are generally considered to have reached the Pacific Northwest in the mid-1800s with the arrival of European-American settlers. Invasive species such as...

  8. Plant-soil interactions promote co-occurrence of three nonnative woody shrubs.

    Science.gov (United States)

    Kuebbing, Sara E; Classen, Aimée T; Call, Jaime J; Henning, Jeremiah A; Simberloff, Daniel

    2015-08-01

    Ecosystems containing multiple nonnative plant species are common, but mechanisms promoting their co-occurrence are understudied. Plant-soil interactions contribute to the dominance of singleton species in nonnative ranges because many nonnatives experience stronger positive feedbacks relative to co-occurring natives. Plant-soil interactions could impede other nonnatives if an individual nonnative benefits from its soil community to a greater extent than its neighboring nonnatives, as is seen with natives. However, plant-soil interactions could promote nonnative co-occurrence if a nonnative accumulates beneficial soil mutualists that also assist other nonnatives. Here, we use greenhouse and field experiments to ask whether plant-soil interactions (1) promote the codominance of two common nonnative shrubs (Ligustrum sinense and Lonicera maackii) and (2) facilitate the invasion of a less-common nonnative shrub (Rhamnus davurica) in deciduous forests of the southeastern United States. In the greenhouse, we found that two of the nonnatives, L. maackii and R. davurica, performed better in soils conditioned by nonnative shrubs compared to uninvaded forest soils, which. suggests that positive feedbacks among co-occurring nonnative shrubs can promote continued invasion of a site. In both greenhouse and field experiments, we found consistent signals that the codominance of the nonnatives L. sinense and L. maackii may be at least partially explained by the increased growth of L. sinense in L. maackii soils. Overall, significant effects of plant-soil interactions on shrub performance indicate that plant-soil interactions can potentially structure the co-occurrence patterns of these nonnatives.

  9. Neighbour tolerance, not suppression, provides competitive advantage to non-native plants.

    Science.gov (United States)

    Golivets, Marina; Wallin, Kimberly F

    2018-05-01

    High competitive ability has often been invoked as a key determinant of invasion success and ecological impacts of non-native plants. Yet our understanding of the strategies that non-natives use to gain competitive dominance remains limited. Particularly, it remains unknown whether the two non-mutually exclusive competitive strategies, neighbour suppression and neighbour tolerance, are equally important for the competitive advantage of non-native plants. Here, we analyse data from 192 peer-reviewed studies on pairwise plant competition within a Bayesian multilevel meta-analytic framework and show that non-native plants outperform their native counterparts due to high tolerance of competition, as opposed to strong suppressive ability. Competitive tolerance ability of non-native plants was driven by neighbour's origin and was expressed in response to a heterospecific native but not heterospecific non-native neighbour. In contrast to natives, non-native species were not more suppressed by hetero- vs. conspecific neighbours, which was partially due to higher intensity of intraspecific competition among non-natives. Heterogeneity in the data was primarily associated with methodological differences among studies and not with phylogenetic relatedness among species. Altogether, our synthesis demonstrates that non-native plants are competitively distinct from native plants and challenges the common notion that neighbour suppression is the primary strategy for plant invasion success. © 2018 John Wiley & Sons Ltd/CNRS.

  10. Nonnative plant response to silvicultural treatments: A model based on disturbance, propagule pressure, and competitive abilities

    Science.gov (United States)

    Steve Sutherland; Cara R. Nelson

    2010-01-01

    Invasion by nonnative plants can result in substantial adverse effects on the functions of native forest ecosystems, including nutrient cycling and fire regimes. Thus, forest managers need to be aware of the potential impacts of management activities, including silvicultural treatments, on nonnative vegetation. To aid in that effort, we created a conceptual model of...

  11. Negative, neutral, and positive interactions among nonnative plants: patterns, processes, and management implications.

    Science.gov (United States)

    Kuebbing, Sara E; Nuñez, Martin A

    2015-02-01

    The movement of species is one of the most pervasive forms of global change, and few ecosystems remain uninvaded by nonnative species. Studying species interactions is crucial for understanding their distribution and abundance, particularly for nonnative species because interactions may influence the probability of invasion and consequent ecological impact. Interactions among nonnatives are relatively understudied, though the likelihood of nonnative species co-occurrence is high. We quantify and describe the types of interactions among nonnative plants and determine what factors affect interaction outcomes for ecosystems globally. We reviewed 65 studies comprising 201 observations and recorded the interaction type, traits of the interacting species, and study characteristics. We conducted a census of interaction types and a meta-analysis of experiments that tested nonnative competition intensity. Both methods showed that negative and neutral interactions prevailed, and a number of studies reported that the removal of a dominant nonnative led to competitive release of other nonnatives. Positive interactions were less frequently reported and positive mean effect sizes were rare, but the plant characteristics nitrogen fixation, life cycle (annual or perennial), and functional group significantly influenced positive interactions. Positive interactions were three times more frequent when a neighboring nonnative was a nitrogen fixer and 3.5 times lower when a neighboring nonnative was an annual. Woody plants were two or four times more likely to have positive interactions relative to grasses or herbs, respectively. The prevalence of negative interactions suggests that managers should prepare for reinvasion of sites when treating dominant nonnatives. Though positive interactions were infrequent, managers may be able to anticipate positive interactions among nonnatives based upon traits of the co-occurring invaders. Predicting positive nonnative interactions is an

  12. Arthropod assemblages on native and nonnative plant species of a coastal reserve in California.

    Science.gov (United States)

    Fork, Susanne K

    2010-06-01

    Biological invasions by nonnative plant species are a widespread phenomenon. Many studies have shown strong ecological impacts of plant invasions on native plant communities and ecosystem processes. Far fewer studies have examined effects on associated animal communities. From the perspective of a reserve's land management, I addressed the question of whether arthropod assemblages on two nonnative plant species of concern were impoverished compared with those assemblages associated with two predominant native plant species of that reserve. If the nonnative plant species, Conium maculatum L., and Phalaris aquatica L., supported highly depauperate arthropod assemblages compared with the native plant species, Baccharis pilularis De Candolle and Leymus triticoides (Buckley) Pilger, this finding would provide additional support for prioritizing removal of nonnatives and restoration of natives. I assessed invertebrate assemblages at the taxonomic levels of arthropod orders, Coleoptera families, and Formicidae species, using univariate analyses to examine community attributes (richness and abundance) and multivariate techniques to assess arthropod assemblage community composition differences among plant species. Arthropod richness estimates by taxonomic level between native and nonnative vegetation showed varying results. Overall, arthropod richness of the selected nonnative plants, examined at higher taxonomic resolution, was not necessarily less diverse than two of common native plants found on the reserve, although differences were found among plant species. Impacts of certain nonnative plant species on arthropod assemblages may be more difficult to elucidate than those impacts shown on native plants and ecosystem processes.

  13. Challenging the view that invasive non-native plants are not a significant threat to the floristic diversity of Great Britain

    Czech Academy of Sciences Publication Activity Database

    Hulme, P. E.; Pauchard, A.; Pyšek, Petr; Vila, M.; Alba, Christina; Blackburn, T. M.; Bullock, J. M.; Chytrý, M.; Dawson, W.; Dunn, A. M.; Essl, F.; Genovesi, P.; Maskell, L. C.; Meyerson, L. A.; Nunez, M. A.; Pergl, Jan; Pescott, O. L.; Pocock, M. J. O.; Richardson, D. M.; Roy, H. E.; Smart, S. M.; Štajerová, Kateřina; Stohlgren, T.; van Kleunen, M.; Winter, M.

    2015-01-01

    Roč. 112, č. 23 (2015), E2988-E2989 ISSN 0027-8424 Institutional support: RVO:67985939 Keywords : plant invasions * impact * misleading analyse Subject RIV: EH - Ecology, Behaviour Impact factor: 9.423, year: 2015

  14. Native fruit traits may mediate dispersal competition between native and non-native plants

    Directory of Open Access Journals (Sweden)

    Clare Aslan

    2012-02-01

    Full Text Available Seed disperser preferences may mediate the impact of invasive, non-native plant species on their new ecological communities. Significant seed disperser preference for invasives over native species could facilitate the spread of the invasives while impeding native plant dispersal. Such competition for dispersers could negatively impact the fitness of some native plants. Here, we review published literature to identify circumstances under which preference for non-native fruits occurs. The importance of fruit attraction is underscored by several studies demonstrating that invasive, fleshy-fruited plant species are particularly attractive to regional frugivores. A small set of studies directly compare frugivore preference for native vs. invasive species, and we find that different designs and goals within such studies frequently yield contrasting results. When similar native and non-native plant species have been compared, frugivores have tended to show preference for the non-natives. This preference appears to stem from enhanced feeding efficiency or accessibility associated with the non-native fruits. On the other hand, studies examining preference within existing suites of co-occurring species, with no attempt to maximize fruit similarity, show mixed results, with frugivores in most cases acting opportunistically or preferring native species. A simple, exploratory meta-analysis finds significant preference for native species when these studies are examined as a group. We illustrate the contrasting findings typical of these two approaches with results from two small-scale aviary experiments we conducted to determine preference by frugivorous bird species in northern California. In these case studies, native birds preferred the native fruit species as long as it was dissimilar from non-native fruits, while non-native European starlings preferred non-native fruit. However, native birds showed slight, non-significant preference for non-native fruit

  15. Evolution of an invasive species research program and implications for large-scale management of a non-native, invasive plant pathogen

    Science.gov (United States)

    Christopher A. Lee; Janice M. Alexander; Susan J. Frankel; Yana Valachovic

    2012-01-01

    We conducted a research needs assessment (RNA) in 2010 to gather opinions of "experts" and a larger public on research priorities for Phytophthora ramorum, the pathogen that causes sudden oak death in forest trees and Ramorum blight in ornamental plants. We place these 2010 findings in context with findings of similar P. ramorum...

  16. Community-level plant-soil feedbacks explain landscape distribution of native and non-native plants.

    Science.gov (United States)

    Kulmatiski, Andrew

    2018-02-01

    Plant-soil feedbacks (PSFs) have gained attention for their potential role in explaining plant growth and invasion. While promising, most PSF research has measured plant monoculture growth on different soils in short-term, greenhouse experiments. Here, five soil types were conditioned by growing one native species, three non-native species, or a mixed plant community in different plots in a common-garden experiment. After 4 years, plants were removed and one native and one non-native plant community were planted into replicate plots of each soil type. After three additional years, the percentage cover of each of the three target species in each community was measured. These data were used to parameterize a plant community growth model. Model predictions were compared to native and non-native abundance on the landscape. Native community cover was lowest on soil conditioned by the dominant non-native, Centaurea diffusa , and non-native community cover was lowest on soil cultivated by the dominant native, Pseudoroegneria spicata . Consistent with plant growth on the landscape, the plant growth model predicted that the positive PSFs observed in the common-garden experiment would result in two distinct communities on the landscape: a native plant community on native soils and a non-native plant community on non-native soils. In contrast, when PSF effects were removed, the model predicted that non-native plants would dominate all soils, which was not consistent with plant growth on the landscape. Results provide an example where PSF effects were large enough to change the rank-order abundance of native and non-native plant communities and to explain plant distributions on the landscape. The positive PSFs that contributed to this effect reflected the ability of the two dominant plant species to suppress each other's growth. Results suggest that plant dominance, at least in this system, reflects the ability of a species to suppress the growth of dominant competitors

  17. Invasive non-native species' provision of refugia for endangered native species.

    Science.gov (United States)

    Chiba, Satoshi

    2010-08-01

    The influence of non-native species on native ecosystems is not predicted easily when interspecific interactions are complex. Species removal can result in unexpected and undesired changes to other ecosystem components. I examined whether invasive non-native species may both harm and provide refugia for endangered native species. The invasive non-native plant Casuarina stricta has damaged the native flora and caused decline of the snail fauna on the Ogasawara Islands, Japan. On Anijima in 2006 and 2009, I examined endemic land snails in the genus Ogasawarana. I compared the density of live specimens and frequency of predation scars (from black rats [Rattus rattus]) on empty shells in native vegetation and Casuarina forests. The density of land snails was greater in native vegetation than in Casuarina forests in 2006. Nevertheless, radical declines in the density of land snails occurred in native vegetation since 2006 in association with increasing predation by black rats. In contrast, abundance of Ogasawarana did not decline in the Casuarina forest, where shells with predation scars from rats were rare. As a result, the density of snails was greater in the Casuarina forest than in native vegetation. Removal of Casuarina was associated with an increased proportion of shells with predation scars from rats and a decrease in the density of Ogasawarana. The thick and dense litter of Casuarina appears to provide refugia for native land snails by protecting them from predation by rats; thus, eradication of rats should precede eradication of Casuarina. Adaptive strategies, particularly those that consider the removal order of non-native species, are crucial to minimizing the unintended effects of eradication on native species. In addition, my results suggested that in some cases a given non-native species can be used to mitigate the impacts of other non-native species on native species.

  18. Invasive plants affect prairie soil biology

    Science.gov (United States)

    Non-native or exotic plants often cause ecological and environmental damage in ecosystems where they invade and become established. These invasive plants may be the most serious threat to plant diversity in prairies, especially those in scattered remnants, which may be particularly vulnerable to rap...

  19. Protected-area boundaries as filters of plant invasions.

    Science.gov (United States)

    Foxcroft, Llewellyn C; Jarošík, Vojtěch; Pyšek, Petr; Richardson, David M; Rouget, Mathieu

    2011-04-01

    Human land uses surrounding protected areas provide propagules for colonization of these areas by non-native species, and corridors between protected-area networks and drainage systems of rivers provide pathways for long-distance dispersal of non-native species. Nevertheless, the influence of protected-area boundaries on colonization of protected areas by invasive non-native species is unknown. We drew on a spatially explicit data set of more than 27,000 non-native plant presence records for South Africa's Kruger National Park to examine the role of boundaries in preventing colonization of protected areas by non-native species. The number of records of non-native invasive plants declined rapidly beyond 1500 m inside the park; thus, we believe that the park boundary limited the spread of non-native plants. The number of non-native invasive plants inside the park was a function of the amount of water runoff, density of major roads, and the presence of natural vegetation outside the park. Of the types of human-induced disturbance, only the density of major roads outside the protected area significantly increased the number of non-native plant records. Our findings suggest that the probability of incursion of invasive plants into protected areas can be quantified reliably. ©2010 Society for Conservation Biology.

  20. Invasion of non-native grasses causes a drop in soil carbon storage in California grasslands

    Energy Technology Data Exchange (ETDEWEB)

    Koteen, Laura E; Harte, John [Energy and Resources Group, 310 Barrows Hall, University of California, Berkeley, CA 94720 (United States); Baldocchi, Dennis D, E-mail: lkoteen@berkeley.edu [Department of Environmental Science, Policy and Management, 137 Mulford Hall, University of California, Berkeley, CA 94720 (United States)

    2011-10-15

    Vegetation change can affect the magnitude and direction of global climate change via its effect on carbon cycling among plants, the soil and the atmosphere. The invasion of non-native plants is a major cause of land cover change, of biodiversity loss, and of other changes in ecosystem structure and function. In California, annual grasses from Mediterranean Europe have nearly displaced native perennial grasses across the coastal hillsides and terraces of the state. Our study examines the impact of this invasion on carbon cycling and storage at two sites in northern coastal California. The results suggest that annual grass invasion has caused an average drop in soil carbon storage of 40 Mg/ha in the top half meter of soil, although additional mechanisms may also contribute to soil carbon losses. We attribute the reduction in soil carbon storage to low rates of net primary production in non-native annuals relative to perennial grasses, a shift in rooting depth and water use to primarily shallow sources, and soil respiratory losses in non-native grass soils that exceed production rates. These results indicate that even seemingly subtle land cover changes can significantly impact ecosystem functions in general, and carbon storage in particular.

  1. Invasion of non-native grasses causes a drop in soil carbon storage in California grasslands

    Science.gov (United States)

    Koteen, Laura E.; Baldocchi, Dennis D.; Harte, John

    2011-10-01

    Vegetation change can affect the magnitude and direction of global climate change via its effect on carbon cycling among plants, the soil and the atmosphere. The invasion of non-native plants is a major cause of land cover change, of biodiversity loss, and of other changes in ecosystem structure and function. In California, annual grasses from Mediterranean Europe have nearly displaced native perennial grasses across the coastal hillsides and terraces of the state. Our study examines the impact of this invasion on carbon cycling and storage at two sites in northern coastal California. The results suggest that annual grass invasion has caused an average drop in soil carbon storage of 40 Mg/ha in the top half meter of soil, although additional mechanisms may also contribute to soil carbon losses. We attribute the reduction in soil carbon storage to low rates of net primary production in non-native annuals relative to perennial grasses, a shift in rooting depth and water use to primarily shallow sources, and soil respiratory losses in non-native grass soils that exceed production rates. These results indicate that even seemingly subtle land cover changes can significantly impact ecosystem functions in general, and carbon storage in particular.

  2. Invasion of non-native grasses causes a drop in soil carbon storage in California grasslands

    International Nuclear Information System (INIS)

    Koteen, Laura E; Harte, John; Baldocchi, Dennis D

    2011-01-01

    Vegetation change can affect the magnitude and direction of global climate change via its effect on carbon cycling among plants, the soil and the atmosphere. The invasion of non-native plants is a major cause of land cover change, of biodiversity loss, and of other changes in ecosystem structure and function. In California, annual grasses from Mediterranean Europe have nearly displaced native perennial grasses across the coastal hillsides and terraces of the state. Our study examines the impact of this invasion on carbon cycling and storage at two sites in northern coastal California. The results suggest that annual grass invasion has caused an average drop in soil carbon storage of 40 Mg/ha in the top half meter of soil, although additional mechanisms may also contribute to soil carbon losses. We attribute the reduction in soil carbon storage to low rates of net primary production in non-native annuals relative to perennial grasses, a shift in rooting depth and water use to primarily shallow sources, and soil respiratory losses in non-native grass soils that exceed production rates. These results indicate that even seemingly subtle land cover changes can significantly impact ecosystem functions in general, and carbon storage in particular.

  3. Setting Priorities for Monitoring and Managing Non-native Plants: Toward a Practical Approach.

    Science.gov (United States)

    Koch, Christiane; Jeschke, Jonathan M; Overbeck, Gerhard E; Kollmann, Johannes

    2016-09-01

    Land managers face the challenge to set priorities in monitoring and managing non-native plant species, as resources are limited and not all non-natives become invasive. Existing frameworks that have been proposed to rank non-native species require extensive information on their distribution, abundance, and impact. This information is difficult to obtain and often not available for many species and regions. National watch or priority lists are helpful, but it is questionable whether they provide sufficient information for environmental management on a regional scale. We therefore propose a decision tree that ranks species based on more simple albeit robust information, but still provides reliable management recommendations. To test the decision tree, we collected and evaluated distribution data from non-native plants in highland grasslands of Southern Brazil. We compared the results with a national list from the Brazilian Invasive Species Database for the state to discuss advantages and disadvantages of the different approaches on a regional scale. Out of 38 non-native species found, only four were also present on the national list. If management would solely rely on this list, many species that were identified as spreading based on the decision tree would go unnoticed. With the suggested scheme, it is possible to assign species to active management, to monitoring, or further evaluation. While national lists are certainly important, management on a regional scale should employ additional tools that adequately consider the actual risk of non-natives to become invasive.

  4. Effects of Nonnative Ungulate Removal on Plant Communities and Soil Biogeochemistry in Tropical Forests

    Science.gov (United States)

    Cole, R. J.; Litton, C. M.; Giardina, C. P.; Sparks, J. P.

    2014-12-01

    Non-native ungulates have substantial impacts on native ecosystems globally, altering both plant communities and soil biogeochemistry. Across tropical and temperate ecosystems, land managers fence and remove non-native ungulates to conserve native biodiversity, a costly management action, yet long-term outcomes are not well quantified. Specifically, knowledge gaps include: (i) the magnitude and time frame of plant community recovery; (ii) the response of non-native invasive plants; and (iii) changes to soil biogeochemistry. In 2010, we established a series of paired ungulate presence vs. removal plots that span a 20 yr. chronosequence in tropical montane wet forests on the Island of Hawaii to quantify the impacts and temporal legacy of feral pig removal on plant communities and soil biogeochemistry. We also compared soil biogeochemistry in targeted areas of low and high feral pig impact. Our work shows that both native and non-native vegetation respond positively to release from top-down control following removal of feral pigs, but species of high conservation concern recover only if initially present at the time of non-native ungulate removal. Feral pig impacts on soil biogeochemistry appear to last for at least 20 years following ungulate removal. We observed that both soil physical and chemical properties changed with feral pig removal. Soil bulk density and volumetric water content decreased while extractable base cations and inorganic N increased in low vs. high feral pig impact areas. We hypothesize that altered soil biogeochemistry facilitates continued invasions by non-native plants, even decades after non-native ungulate removal. Future work will concentrate on comparisons between wet and dry forest ecosystems and test whether manipulation of soil nutrients can be used to favor native vs. non-native plant establishment.

  5. Snowpack, fire, and forest disturbance: interactions affect montane invasions by non-native shrubs.

    Science.gov (United States)

    Stevens, Jens T; Latimer, Andrew M

    2015-06-01

    Montane regions worldwide have experienced relatively low plant invasion rates, a trend attributed to increased climatic severity, low rates of disturbance, and reduced propagule pressure relative to lowlands. Manipulative experiments at elevations above the invasive range of non-native species can clarify the relative contributions of these mechanisms to montane invasion resistance, yet such experiments are rare. Furthermore, global climate change and land use changes are expected to cause decreases in snowpack and increases in disturbance by fire and forest thinning in montane forests. We examined the importance of these factors in limiting montane invasions using a field transplant experiment above the invasive range of two non-native lowland shrubs, Scotch broom (Cytisus scoparius) and Spanish broom (Spartium junceum), in the rain-snow transition zone of the Sierra Nevada of California. We tested the effects of canopy closure, prescribed fire, and winter snow depth on demographic transitions of each species. Establishment of both species was most likely at intermediate levels of canopy disturbance, but at this intermediate canopy level, snow depth had negative effects on winter survival of seedlings. We used matrix population models to show that an 86% reduction in winter snowfall would cause a 2.8-fold increase in population growth rates in Scotch broom and a 3.5-fold increase in Spanish broom. Fall prescribed fire increased germination rates, but decreased overall population growth rates by reducing plant survival. However, at longer fire return intervals, population recovery between fires is likely to keep growth rates high, especially under low snowpack conditions. Many treatment combinations had positive growth rates despite being above the current invasive range, indicating that propagule pressure, disturbance, and climate can all strongly affect plant invasions in montane regions. We conclude that projected reductions in winter snowpack and increases in

  6. Nest-location and nest-survival of black-chinned hummingbirds in New Mexico: A comparison between rivers with differing levels of regulation and invasion of nonnative plants

    Science.gov (United States)

    D. Max Smith; Deborah M. Finch; Scott H. Stoleson

    2014-01-01

    We compared plants used as sites for nests and survival of nests of black-chinned hummingbirds (Archilochus alexandri) along two rivers in New Mexico. Along the free-flowing Gila River which was dominated by native plants, most nests were constructed in boxelder (Acer negundo). Along the flow-restricted Middle Rio Grande which was dominated by nonnative plants, most...

  7. The role of wildfire in the establishment and range expansion of nonnative plant species into natural areas: A review of current literature

    Science.gov (United States)

    Mara Johnson; Lisa J. Rew; Bruce D. Maxwell; Steve Sutherland

    2006-01-01

    Nonnative invasive plants are one of the greatest threats to natural ecosystems worldwide (Vitousek et al. 1996). In fact, their spread has been described as "a raging biological wildfire" (Dewey et al. 1995). Disturbances tend to create conditions that are favorable for germination and establishment of plant species. Nonnative plant species are often...

  8. Invasive plants often emanate from southern gardens

    Science.gov (United States)

    J.H. Miller; A. Miller

    2009-01-01

    Did you know that heavenly bamboo, thorny olive, English ivy, Boston fern, privets and many garden favorites are invading forests to their and thus our detriment? Garden clubs should band together to protect our natural vegetation against invasive plants that take over the habitat of the native flora. Often called non-native, exotic, or noxious weeds, they...

  9. Severe plant invasions can increase mycorrhizal fungal abundance and diversity

    DEFF Research Database (Denmark)

    Lekberg, Ylva; Gibbons, Sean; Rosendahl, Søren

    2013-01-01

    Invasions by non-native plants can alter ecosystem functions and reduce native plant diversity, but relatively little is known about their effect on belowground microbial communities. We show that invasions by knapweed (Centaurea stoebe) and leafy spurge (Euphorbia esula, hereafter spurge...... plant provenance.The ISME Journal advance online publication, 14 March 2013; doi:10.1038/ismej.2013.41....

  10. Invasive plants found in Louisiana’s forests, 2009 forest inventory and analysis factsheet

    Science.gov (United States)

    Sonja N. Oswalt; Christopher M. Oswalt

    2012-01-01

    Foresters and ecologists have noted the spread of nonnative invasive species onto U.S. forest land for decades. Despite soaring costs related to the management of and removal of invasive plants, and inestimable environmental impacts (e.g., altered soil chemistry, competition with native species, altered light environment; Pimentel and others 2005), nonnative invasive...

  11. Invasions by two non-native insects alter regional forest species composition and successional trajectories

    Science.gov (United States)

    Randall S. Morin; Andrew M. Liebhold

    2015-01-01

    While invasions of individual non-native phytophagous insect species are known to affect growth and mortality of host trees, little is known about how multiple invasions combine to alter forest dynamics over large regions. In this study we integrate geographical data describing historical invasion spread of the hemlock woolly adelgid, Adelges tsugae...

  12. Contrasting patterns of herbivore and predator pressure on invasive and native plants

    NARCIS (Netherlands)

    Engelkes, T.; Wouters, B.; Bezemer, T.M.; Harvey, J.A.; Putten, van der W.H.

    2012-01-01

    Invasive non-native plant species often harbor fewer herbivorous insects than related native plant species. However, little is known about how herbivorous insects on non-native plants are exposed to carnivorous insects, and even less is known on plants that have recently expanded their ranges within

  13. Nonnative invasive plants in South Carolina: combining phase-2 with phase-3 vegetation structure and diversity pilot data to enhance our understanding of forest health issues

    Science.gov (United States)

    Sonja N. Oswalt

    2006-01-01

    Studies suggest that the Southeast is an area of primary concern with regards to the spread of alien plant species (Miller 2003, Stapanian and others 1998). Data collected by Stapanian and others in 1998 showed that Japanese honeysuckle (Lonicera japonica) occurred over 2 million acres in the Southeast, invading forests and displacing native species. Among the most...

  14. Effects of invasive plants on arthropods.

    Science.gov (United States)

    Litt, Andrea R; Cord, Erin E; Fulbright, Timothy E; Schuster, Greta L

    2014-12-01

    Non-native plants have invaded nearly all ecosystems and represent a major component of global ecological change. Plant invasions frequently change the composition and structure of vegetation communities, which can alter animal communities and ecosystem processes. We reviewed 87 articles published in the peer-reviewed literature to evaluate responses of arthropod communities and functional groups to non-native invasive plants. Total abundance of arthropods decreased in 62% of studies and increased in 15%. Taxonomic richness decreased in 48% of studies and increased in 13%. Herbivorous arthropods decreased in response to plant invasions in 48% of studies and increased in 17%, likely due to direct effects of decreased plant diversity. Predaceous arthropods decreased in response to invasive plants in 44% of studies, which may reflect indirect effects due to reductions in prey. Twenty-two percent of studies documented increases in predators, which may reflect changes in vegetation structure that improved mobility, survival, or web-building for these species. Detritivores increased in 67% of studies, likely in response to increased litter and decaying vegetation; no studies documented decreased abundance in this functional group. Although many researchers have examined effects of plant invasions on arthropods, sizeable information gaps remain, specifically regarding how invasive plants influence habitat and dietary requirements. Beyond this, the ability to predict changes in arthropod populations and communities associated with plant invasions could be improved by adopting a more functional and mechanistic approach. Understanding responses of arthropods to invasive plants will critically inform conservation of virtually all biodiversity and ecological processes because so many organisms depend on arthropods as prey or for their functional roles, including pollination, seed dispersal, and decomposition. Given their short generation times and ability to respond rapidly to

  15. Alien plant invasions in European woodlands

    Czech Academy of Sciences Publication Activity Database

    Wagner, V.; Chytrý, M.; Jiménez-Alfaro, B.; Pergl, Jan; Hennekens, S. M.; Biurrun, I.; Knollová, I.; Berg, C.; Vassilev, K.; Rodwell, J. S.; Škvorc, Ž.; Jandt, U.; Ewald, J.; Jansen, F.; Tsiripidis, I.; Botta-Dukát, Z.; Casella, L.; Attorre, F.; Rašomavičius, V.; Ćušterevska, R.; Schaminée, J.H.J.; Brunet, J.; Lenoir, J.; Svenning, J.-C.; Kacki, Z.; Petrášová-Šibíková, M.; Šilc, U.; García-Mijangos, I.; Campos, J. A.; Fernández-González, F.; Wohlgemuth, T.; Onyshchenko, V.; Pyšek, Petr

    2017-01-01

    Roč. 23, č. 9 (2017), s. 969-981 ISSN 1366-9516 R&D Projects: GA ČR GB14-36079G Grant - others:AV ČR(CZ) AP1002 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985939 Keywords : neophyte * non-native * invasive plants * EUNIS * forests Subject RIV: EH - Ecology, Behaviour OBOR OECD: Biodiversity conservation Impact factor: 4.391, year: 2016

  16. Phytophagous insects on native and non-native host plants: combining the community approach and the biogeographical approach.

    Directory of Open Access Journals (Sweden)

    Kim Meijer

    Full Text Available During the past centuries, humans have introduced many plant species in areas where they do not naturally occur. Some of these species establish populations and in some cases become invasive, causing economic and ecological damage. Which factors determine the success of non-native plants is still incompletely understood, but the absence of natural enemies in the invaded area (Enemy Release Hypothesis; ERH is one of the most popular explanations. One of the predictions of the ERH, a reduced herbivore load on non-native plants compared with native ones, has been repeatedly tested. However, many studies have either used a community approach (sampling from native and non-native species in the same community or a biogeographical approach (sampling from the same plant species in areas where it is native and where it is non-native. Either method can sometimes lead to inconclusive results. To resolve this, we here add to the small number of studies that combine both approaches. We do so in a single study of insect herbivory on 47 woody plant species (trees, shrubs, and vines in the Netherlands and Japan. We find higher herbivore diversity, higher herbivore load and more herbivory on native plants than on non-native plants, generating support for the enemy release hypothesis.

  17. Impacts of nonnative invasive species on US forests and recommendations for policy and management

    Science.gov (United States)

    W. Keith Moser; Edward L. Barnard; Ronald F. Billings; Susan J. Crocker; Andrew N. Gray; George G. Ice; Mee-Sook Kim; Richard Reid; Sue U. Rodman; William H. McWilliams

    2009-01-01

    The introduction of nonnative invasive species (NNIS) into the United States has had tremendous impacts on the nation's commercial and urban forest resources. Of principal concern are the effects of NNIS on forest composition, structure, function, productivity, and patterns of carbon sequestration. In 2006, the Society of American Foresters commissioned an ad hoc...

  18. Evolution under changing climates: climatic niche stasis despite rapid evolution in a non-native plant.

    Science.gov (United States)

    Alexander, Jake M

    2013-09-22

    A topic of great current interest is the capacity of populations to adapt genetically to rapidly changing climates, for example by evolving the timing of life-history events, but this is challenging to address experimentally. I use a plant invasion as a model system to tackle this question by combining molecular markers, a common garden experiment and climatic niche modelling. This approach reveals that non-native Lactuca serriola originates primarily from Europe, a climatic subset of its native range, with low rates of admixture from Asia. It has rapidly refilled its climatic niche in the new range, associated with the evolution of flowering phenology to produce clines along climate gradients that mirror those across the native range. Consequently, some non-native plants have evolved development times and grow under climates more extreme than those found in Europe, but not among populations from the native range as a whole. This suggests that many plant populations can adapt rapidly to changed climatic conditions that are already within the climatic niche space occupied by the species elsewhere in its range, but that evolution to conditions outside of this range is more difficult. These findings can also help to explain the prevalence of niche conservatism among non-native species.

  19. The Spread of Non-native Plant Species Collection of Cibodas Botanical Garden into Mt. Gede Pangrango National Park

    Directory of Open Access Journals (Sweden)

    Musyarofah Zuhri

    2013-05-01

    Full Text Available The role of botanic garden in spread of non-native plant species has concerned of international worldwide. This study aimed to study the extent of non-native plant species from Cibodas Botanical Garden (CBG which invades into natural rainforest. A line transect was made edge-to-interior with 1,600 m in distance from CBG boundary. Result showed that distance from CBG was not significant in correlation with non-native tree and treelet density. Furthermore, presence of existing CBG’s plant collection was not a single aspect which influenced presence and abundance. Three invasive species possibly was escape from CBG and it showed edge-to-interior in stems density, i.e. Cinchona pubescens, Calliandra calothyrsus and Cestrum aurantiacum. The patterns of non-native species were influenced by presence of ditch across transect, existence of human trail, and the other non-native species did not have general pattern of spread distribution. Overall, botanical gardens should minimize the risk of unintentional introduced plant by perform site-specific risk assessment.

  20. Invasion strategy and abiotic activity triggers for non-native gobiids of the River Rhine.

    Directory of Open Access Journals (Sweden)

    Jan Baer

    Full Text Available The 24 hour activity patterns of three non-native gobiids (round goby Neogobius melanostomus, Western tubenose goby Proterorhinus semilunaris and bighead goby Ponticola kessleri were assessed over 46 consecutive months between 2011 and 2014 from their occurrence in the cooling water intake of a nuclear power plant on the River Rhine, Germany. In total, 117717 gobiids were identified and classified. The occurrence of all three species varied strongly between sampling years, and species-specific activity triggers were identified. The activity of juveniles of all three gobiids species was positively temperature dependent while adult tubenose goby activity appeared to be negatively temperature dependent. Increasing fluvial discharge in the adjoining main river stimulated the activity of juvenile round goby but inhibited activity of adult tubenose goby. Except for adult bighead goby, activity was also structured by time of day, but with no uniform mean. Meteorological factors such as precipitation, air pressure and duration of sunshine hours had little or no influence on gobiid activity. On selected rare occasions, mainly at night, all three species exhibited pulsed swarming behaviour, with thousands of individuals recorded in the intake water. Round goby swarms exhibited both the highest intensity and the largest swarming individuals, suggesting a potential competitive advantage over tubenose and bighead goby. Electric fishing surveys in natural river stretches corroborated this observation. Negative effects on the native fish fauna were apparent only for the bullhead, Cottus gobio. The activity triggers identified offer a unique insight into the invasion mechanisms of these ecosystem-changing non-native gobiids.

  1. The legacy of Charles Marlatt and efforts to limit plant pest invasions

    Science.gov (United States)

    Andrew M. Liebhold; Robert L. Griffin

    2016-01-01

    The problem of invasions by non-native plant pests has come to dominate the field of applied entomology. Most of the damaging insect pests of agriculture and forestry are non-native (Sailer 1978, Aukema et al. 2010) and this is a problem being faced around the world. This problem did not arise overnight; instead, there has been a steady accumulation of non-native...

  2. E-commerce trade in invasive plants.

    Science.gov (United States)

    Humair, Franziska; Humair, Luc; Kuhn, Fabian; Kueffer, Christoph

    2015-12-01

    Biological invasions are a major concern in conservation, especially because global transport of species is still increasing rapidly. Conservationists hope to anticipate and thus prevent future invasions by identifying and regulating potentially invasive species through species risk assessments and international trade regulations. Among many introduction pathways of non-native species, horticulture is a particularly important driver of plant invasions. In recent decades, the horticultural industry expanded globally and changed structurally through the emergence of new distribution channels, including internet trade (e-commerce). Using an automated search algorithm, we surveyed, on a daily basis, e-commerce trade on 10 major online auction sites (including eBay) of approximately three-fifths of the world's spermatophyte flora. Many recognized invasive plant species (>500 species) (i.e., species associated with ecological or socio-economic problems) were traded daily worldwide on the internet. A markedly higher proportion of invasive than non-invasive species were available online. Typically, for a particular plant family, 30-80% of recognized invasive species were detected on an auction site, but only a few percentages of all species in the plant family were detected on a site. Families that were more traded had a higher proportion of invasive species than families that were less traded. For woody species, there was a significant positive relationship between the number of regions where a species was sold and the number of regions where it was invasive. Our results indicate that biosecurity is not effectively regulating online plant trade. In the future, automated monitoring of e-commerce may help prevent the spread of invasive species, provide information on emerging trade connectivity across national borders, and be used in horizon scanning exercises for early detection of new species and their geographic source areas in international trade. © 2015 Society for

  3. Granivory of invasive, naturalized, and native plants in communities differentially susceptible to invasion

    Science.gov (United States)

    B. M. Connolly; D. E. Pearson; R. N. Mack

    2014-01-01

    Seed predation is an important biotic filter that can influence abundance and spatial distributions of native species through differential effects on recruitment. This filter may also influence the relative abundance of nonnative plants within habitats and the communities' susceptibility to invasion via differences in granivore identity, abundance, and food...

  4. A management guide for invasive plants in southern forests

    Science.gov (United States)

    James H. Miller; Steven T. Manning; Stephen F. Enloe

    2013-01-01

    Invasions of nonnative plants into forests of the Southern United States continue to spread and include new species, increasingly eroding forest productivity, hindering forest use and management activities, and degrading diversity and wildlife habitat. This book provides the latest information on how to organize and enact prevention programs, build strategies,...

  5. An invasion risk map for non-native aquatic macrophytes of the Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    Argantonio Rodríguez-Merino

    2017-05-01

    Full Text Available Freshwater systems are particularly susceptible to non-native organisms, owing to their high sensitivity to the impacts that are caused by these organisms. Species distribution models, which are based on both environmental and socio-economic variables, facilitate the identification of the most vulnerable areas for the spread of non-native species. We used MaxEnt to predict the potential distribution of 20 non-native aquatic macrophytes in the Iberian Peninsula. Some selected variables, such as the temperature seasonality and the precipitation in the driest quarter, highlight the importance of the climate on their distribution. Notably, the human influence in the territory appears as a key variable in the distribution of studied species. The model discriminated between favorable and unfavorable areas with high accuracy. We used the model to build an invasion risk map of aquatic macrophytes for the Iberian Peninsula that included results from 20 individual models. It showed that the most vulnerable areas are located near to the sea, the major rivers basins, and the high population density areas. These facts suggest the importance of the human impact on the colonization and distribution of non-native aquatic macrophytes in the Iberian Peninsula, and more precisely agricultural development during the Green Revolution at the end of the 70’s. Our work also emphasizes the utility of species distribution models for the prevention and management of biological invasions.

  6. Vision of a cyberinfrastructure for nonnative, invasive species management

    Science.gov (United States)

    2008-01-01

    Although the quantity of data on the location, status, and management of invasive species is ever increasing, invasive species data sets are often difficult to obtain and integrate. A cyberinfrastructure for such information could make these data available for Internet users. The data can be used to create regional watch lists, to send e-mail alerts when a new species enters a region, to construct models of species' current and future distributions, and to inform management. Although the exchange of environmental data over the Internet in the form of raster data is maturing, and the exchange of species occurrence data is developing quickly, there is room for improvement. In this article, we present a vision for a comprehensive invasive species cyberinfrastructure that is capable of accessing data effectively, creating models of invasive species spread, and distributing this information.

  7. Periphyton density is similar on native and non-native plant species

    NARCIS (Netherlands)

    Grutters, B.M.C.; Gross, Elisabeth M.; van Donk, E.; Bakker, E.S.

    2017-01-01

    Non-native plants increasingly dominate the vegetation in aquatic ecosystems and thrive in eutrophic conditions. In eutrophic conditions, submerged plants risk being overgrown by epiphytic algae; however, if non-native plants are less susceptible to periphyton than natives, this would contribute to

  8. Growth strategy, phylogeny and stoichiometry determine the allelopathic potential of native and non-native plants

    NARCIS (Netherlands)

    Grutters, Bart M.C.; Saccomanno, Benedetta; Gross, Elisabeth M.; Van de Waal, Dedmer B.; van Donk, Ellen; Bakker, Elisabeth S.

    2017-01-01

    Secondary compounds can contribute to the success of non-native plant species if they reduce damage by native herbivores or inhibit the growth of native plant competitors. However, there is opposing evidence on whether the secondary com- pounds of non-native plant species are stronger than those of

  9. Modelling the introduction and spread of non-native species: international trade and climate change drive ragweed invasion.

    Science.gov (United States)

    Chapman, Daniel S; Makra, László; Albertini, Roberto; Bonini, Maira; Páldy, Anna; Rodinkova, Victoria; Šikoparija, Branko; Weryszko-Chmielewska, Elżbieta; Bullock, James M

    2016-09-01

    Biological invasions are a major driver of global change, for which models can attribute causes, assess impacts and guide management. However, invasion models typically focus on spread from known introduction points or non-native distributions and ignore the transport processes by which species arrive. Here, we developed a simulation model to understand and describe plant invasion at a continental scale, integrating repeated transport through trade pathways, unintentional release events and the population dynamics and local anthropogenic dispersal that drive subsequent spread. We used the model to simulate the invasion of Europe by common ragweed (Ambrosia artemisiifolia), a globally invasive plant that causes serious harm as an aeroallergen and crop weed. Simulations starting in 1950 accurately reproduced ragweed's current distribution, including the presence of records in climatically unsuitable areas as a result of repeated introduction. Furthermore, the model outputs were strongly correlated with spatial and temporal patterns of ragweed pollen concentrations, which are fully independent of the calibration data. The model suggests that recent trends for warmer summers and increased volumes of international trade have accelerated the ragweed invasion. For the latter, long distance dispersal because of trade within the invaded continent is highlighted as a key invasion process, in addition to import from the native range. Biosecurity simulations, whereby transport through trade pathways is halted, showed that effective control is only achieved by early action targeting all relevant pathways. We conclude that invasion models would benefit from integrating introduction processes (transport and release) with spread dynamics, to better represent propagule pressure from native sources as well as mechanisms for long-distance dispersal within invaded continents. Ultimately, such integration may facilitate better prediction of spatial and temporal variation in invasion

  10. Herbicides: an unexpected ally for native plants in the war against invasive species

    Science.gov (United States)

    Andrea Watts; Tim Harrington; Dave Peter

    2015-01-01

    Herbicides are primarily used for protecting agricultural crops from weeds and controlling vegetation competition in newly planted forest stands. Yet for over 40 years, they have also proven useful in controlling invasive plant species in natural areas. Nonnative invasive plant species, if not controlled, can displace native species and disrupt an ecosystem by changing...

  11. Plant invasions in China: an emerging hot topic in invasion science

    Directory of Open Access Journals (Sweden)

    Jian Liu

    2012-12-01

    Full Text Available China has shown a rapid economic development in recent decades, and several drivers of this change are known to enhance biological invasions, a major cause of biodiversity loss. Here we review the current state of research on plant invasions in China by analyzing papers referenced in the ISI Web of Knowledge. Since 2001, the number of papers has increased exponentially, indicating that plant invasions in China are an emerging hot topic in invasion science. The analyzed papers cover a broad range of methodological approaches and research topics. While more that 250 invasive plant species with negative impacts have been reported from China, only a few species have been considered in more than a handful of papers (in order of decreasing number of references: Spartina alterniflora, Ageratina adenophora, Mikania micrantha, Alternanthera philoxeroides, Solidago canadensis, Eichhornia crassipes. Yet this selection might rather reflect the location of research teams than the most invasive plant species in China. Considering the previous achievements in China found in our analysis research in plant invasions could be expanded by (1 compiling comprehensive lists of non-native plant species at the provincial and national scales and to include species that are native to one part of China but non-native to others in these lists; (2 strengthening pathways studies (primary introduction to the country, secondary releases within the country to enhance prevention and management; and (3 assessing impacts of invasive species at different spatial scales (habitats, regions and in relation to conservation resources.

  12. Differences in Competitive Ability between Plants from Nonnative and Native Populations of a Tropical Invader Relates to Adaptive Responses in Abiotic and Biotic Environments

    Science.gov (United States)

    Liao, Zhi-Yong; Zhang, Ru; Barclay, Gregor F.; Feng, Yu-Long

    2013-01-01

    The evolution of competitive ability of invasive plant species is generally studied in the context of adaptive responses to novel biotic environments (enemy release) in introduced ranges. However, invasive plants may also respond to novel abiotic environments. Here we studied differences in competitive ability between Chromolaena odorata plants of populations from nonnative versus native ranges, considering biogeographical differences in both biotic and abiotic environments. An intraspecific competition experiment was conducted at two nutrient levels in a common garden. In both low and high nutrient treatments, C. odorata plants from nonnative ranges showed consistently lower root to shoot ratios than did plants from native ranges grown in both monoculture and competition. In the low nutrient treatment, C. odorata plants from nonnative ranges showed significantly lower competitive ability (competition-driven decreases in plant height and biomass were more), which was associated with their lower root to shoot ratios and higher total leaf phenolic content (defense trait). In the high nutrient treatment, C. odorata plants from nonnative ranges showed lower leaf toughness and cellulosic contents (defense traits) but similar competitive ability compared with plants from native ranges, which was also associated with their lower root to shoot ratios. Our results indicate that genetically based shifts in biomass allocation (responses to abiotic environments) also influence competitive abilities of invasive plants, and provide a first potential mechanism for the interaction between range and environment (environment-dependent difference between ranges). PMID:23977140

  13. Resolving whether botanic gardens are on the road to conservation or a pathway for plant invasions.

    Science.gov (United States)

    Hulme, Philip E

    2015-06-01

    A global conservation goal is to understand the pathways through which invasive species are introduced into new regions. Botanic gardens are a pathway for the introduction of invasive non-native plants, but a quantitative assessment of the risks they pose has not been performed. I analyzed data on the living collections of over 3000 botanic gardens worldwide to quantify the temporal trend in the representation of non-native species; the relative composition of threatened, ornamental, or invasive non-native plant species; and the frequency with which botanic gardens implement procedures to address invasive species. While almost all of the world's worst invasive non-native plants occurred in one or more living collections (99%), less than one-quarter of red-listed threatened species were cultivated (23%). Even when cultivated, individual threatened species occurred in few living collections (7.3), while non-native species were on average grown in 6 times as many botanic gardens (44.3). As a result, a botanic garden could, on average, cultivate four times as many invasive non-native species (20) as red-listed threatened species (5). Although the risk posed by a single living collection is small, the probability of invasion increases with the number of botanic gardens within a region. Thus, while both the size of living collections and the proportion of non-native species cultivated have declined during the 20th century, this reduction in risk is offset by the 10-fold increase in the number of botanic gardens established worldwide. Unfortunately, botanic gardens rarely implement regional codes of conduct to prevent plant invasions, few have an invasive species policy, and there is limited monitoring of garden escapes. This lack of preparedness is of particular concern given the rapid increase in living collections worldwide since 1950, particularly in South America and Asia, and highlights past patterns of introduction will be a poor guide to determining future

  14. Effects of ecological restoration alternative treatments on nonnative plant species establishment

    Science.gov (United States)

    Michael T. Stoddard; Christopher M. McGlone; Peter Z. Fule

    2008-01-01

    Disturbances generated by forest restoration treatments have the potential for enhancing the establishment of nonnative species thereby impeding long-term native plant recovery. In a ponderosa pine forest next to the Fort Valley Experimental Forest, Arizona, we examined the establishment of nonnative species after three alternative treatments with different intensities...

  15. Non-native vascular plants from Canary Islands (Spain): nomenclatural and taxonomical adjustments

    OpenAIRE

    Verloove, F.

    2013-01-01

    Se propone correcciones taxonómicas y nomenclaturales respecto a 88 taxones no nativos de la lista de plantas vasculares de las Islas Canarias (España). Non-native vascular plants from Canary Islands (Spain): nomenclatural and taxonomical adjustments. Corrections and other adjustments are proposed for 88 non-native taxa from the checklist of vascular plants from the Canary Islands (Spain).

  16. Genetically based differentiation in growth of multiple non-native plant species along a steep environmental gradient.

    Science.gov (United States)

    Haider, Sylvia; Kueffer, Christoph; Edwards, Peter J; Alexander, Jake M

    2012-09-01

    A non-native plant species spreading along an environmental gradient may need to adjust its growth to the prevailing conditions that it encounters by a combination of phenotypic plasticity and genetic adaptation. There have been several studies of how non-native species respond to changing environmental conditions along latitudinal gradients, but much less is known about elevational gradients. We conducted a climate chamber experiment to investigate plastic and genetically based growth responses of 13 herbaceous non-native plants along an elevational gradient from 100 to 2,000 m a.s.l. in Tenerife. Conditions in the field ranged from high anthropogenic disturbance but generally favourable temperatures for plant growth in the lower half of the gradient, to low disturbance but much cooler conditions in the upper half. We collected seed from low, mid and high elevations and grew them in climate chambers under the characteristic temperatures at these three elevations. Growth of all species was reduced under lower temperatures along both halves of the gradient. We found consistent genetically based differences in growth over the upper elevational gradient, with plants from high-elevation sites growing more slowly than those from mid-elevation ones, while the pattern in the lower part of the gradient was more mixed. Our data suggest that many non-native plants might respond to climate along elevational gradients by genetically based changes in key traits, especially at higher elevations where low temperatures probably impose a stronger selection pressure. At lower elevations, where anthropogenic influences are greater, higher gene flow and frequent disturbance might favour genotypes with broad ecological amplitudes. Thus the importance of evolutionary processes for invasion success is likely to be context-dependent.

  17. Invasion by nonnative brook trout in Panther Creek, Idaho: Roles of habitat quality, connectivity, and biotic resistance

    Science.gov (United States)

    Joseph R. Benjamin

    2006-01-01

    Theoretical models suggest the invasion of nonnative freshwater species is facilitated through the interaction of three factors: biotic resistance, habitat quality, and connectivity. We measured variables that represented each component to determine which were associated with small (150 mm) brook trout occurrence in Panther Creek, a tributary...

  18. Invasive Plant Management Plan for the Oak Ridge Reservation

    Energy Technology Data Exchange (ETDEWEB)

    Giffen, Neil R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McCracken, Kitty [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-09-01

    Invasive non-native plant species have become one of the greatest ecological threats across the country and around the world. Actively managing incursions of invasive plants is crucial to maintaining ecosystems, protecting natural resources, and ensuring proper function of facilities and their support infrastructures, power lines and other utility rights-of-way (ROWs), communications structures, roadways, and waterways. Invasive plants can threaten cultural resources, public and private properties, forests, wetlands, and other natural areas through increased risks of fire and storm damage, as well as decrease native plant diversity, particularly disrupting vital habitats of threatened and endangered species, both plant and animal. In 2000, the Federal Plant Protection Act came into effect. Under this Act, federal agencies are required to develop and coordinate an undesirable plants management program for control of invasive plants on federal lands under each agency’s respective jurisdiction. The agency must adequately fund the undesirable plants management program using an Integrated Pest Management Plan. Additionally, each agency is required to implement cooperative agreements with local and state agencies, as well as other federal agencies, to manage undesirable plants on federal lands under the agency’s jurisdiction. The US Department of Energy (DOE) takes its responsibility for addressing invasive and undesirable plant issues very seriously. Many DOE sites have programs to control invasive pest plant species. DOE has taken a proactive stance toward invasive plant control, and the Invasive Plant Management Plan— created to meet regulatory requirements of federal laws, executive orders, presidential memos, contracts, and agreements on DOE’s Oak Ridge Reservation (ORR)—has been in effect since 2004. This document represents the second revision of this plan.

  19. Granivory of invasive, naturalized, and native plants in communities differentially susceptible to invasion.

    Science.gov (United States)

    Connolly, B M; Pearson, D E; Mack, R N

    2014-07-01

    Seed predation is an important biotic filter that can influence abundance and spatial distributions of native species through differential effects on recruitment. This filter may also influence the relative abundance of nonnative plants within habitats and the communities' susceptibility to invasion via differences in granivore identity, abundance, and food preference. We evaluated the effect of postdispersal seed predators on the establishment of invasive, naturalized, and native species within and between adjacent forest and steppe communities of eastern Washington, USA that differ in severity of plant invasion. Seed removal from trays placed within guild-specific exclosures revealed that small mammals were the dominant seed predators in both forest and steppe. Seeds of invasive species (Bromus tectorum, Cirsium arvense) were removed significantly less than the seeds of native (Pseudoroegneria spicata, Balsamorhiza sagittata) and naturalized (Secale cereale, Centaurea cyanus) species. Seed predation limited seedling emergence and establishment in both communities in the absence of competition in a pattern reflecting natural plant abundance: S. cereale was most suppressed, B. tectorum was least suppressed, and P. spicata was suppressed at an intermediate level. Furthermore, seed predation reduced the residual seed bank for all species. Seed mass correlated with seed removal rates in the forest and their subsequent effects on plant recruitment; larger seeds were removed at higher rates than smaller seeds. Our vegetation surveys indicate higher densities and canopy cover of nonnative species occur in the steppe compared with the forest understory, suggesting the steppe may be more susceptible to invasion. Seed predation alone, however, did not result in significant differences in establishment for any species between these communities, presumably due to similar total small-mammal abundance between communities. Consequently, preferential seed predation by small

  20. Factors influencing plant invasiveness

    Science.gov (United States)

    Yvette Ortega; Dean Pearson

    2009-01-01

    Invasiveness of spotted knapweed and biological control agents. Dean and Yvette are examining the influence of drought on the invasiveness of spotted knapweed (Centaurea maculosa) and its susceptibility to herbivory by biological control agents. In collaboration with the University of Montana and Forest Health Protection, researchers have constructed 150...

  1. Invasion by non-native brook trout in Panther Creek, Idaho: Roles of habitat quality, biotic resistance, and connectivity to source habitats

    Science.gov (United States)

    Joseph R. Benjamin; Jason B. Dunham; Matthew R. Dare

    2007-01-01

    Theoretical models and empirical evidence suggest that the invasion of nonnative species in freshwaters is facilitated through the interaction of three factors: habitat quality, biotic resistance, and connectivity. We measured variables that represented each factor to determine which were associated with the occurrence of nonnative brook trout Salvelinus...

  2. Eight nonnative plants in western Oregon forests: associations with environment and management.

    Science.gov (United States)

    Andrew. Gray

    2005-01-01

    Nonnative plants have tremendous ecological and economic impacts on plant communities globally, but comprehensive data on the distribution and ecological relationships of individual species is often scarce or nonexistent. The objective of this study was to assess the influence of vegetation type, climate, topography, and management history on the distribution and...

  3. Northward invading non-native vascular plant species in and adjacent to Wood Buffalo National Park

    Energy Technology Data Exchange (ETDEWEB)

    Wein, R.W.; Wein, G.; Bahret, S.; Cody, W.J. (Alberta University, Edmonton, AB (Canada). Canadian Circumpolar Institute)

    A survey of the non-native vascular plant species in Wood Buffalo National Park, Canada's largest forested National Park, documented their presence and abundance in key locations. Most of the fifty-four species (nine new records) were found in disturbed sites including roadsides, settlements, farms, areas of altered hydrological regimes, recent bums, and intensive bison grazing. Species that have increased most in geographic area and abundance in recent years include [ital Agropyron repens], [ital Bromus inermis], [ital Chenopodium album], [ital Melilotus spp.], [ital Trifolium spp.], [ital Plantago major], [ital Achillea millefolium], [ital Crepis tectorum] and [ital Sonchus arvensis]. An additional 20 species, now common in the Peace River and Fort Vermilion areas, have the potential to invade the Park if plant communities are subjected to additional stress as northern climates are modified by the greenhouse effect and as other human-caused activities disturb the vegetation. It is recommended that permanent plots be located in key locations and monitored for species invasion and changing abundances as input to management plans.

  4. Plant invasion and speciation along elevational gradients on the oceanic island La Palma, Canary Islands

    DEFF Research Database (Denmark)

    Steinbauer, Manuel; Irl, Severin David Howard; González-Mancebo, Juana Maria

    2017-01-01

    and anthropogenic filters, thus controlling the dispersal and establishment of species. Here, we investigate speciation and invasion processes along elevational gradients. Methods: We assess the vascular plant species richness as well as the number and percentage of endemic species and non-native species...

  5. Invasive plants found in east Texas forests, 2009 forest inventory and analysis factsheet

    Science.gov (United States)

    Sonja N. Oswalt; Christopher M. Oswalt

    2011-01-01

    This science update provides information on the presence and cover of nonnative invasive plants found in forests of the eastern region of the State of Texas based on an annual inventory conducted by the Forest Inventory and Analysis (FIA) Program at the Southern Research Station of the U.S. Department of Agriculture Forest Service in cooperation with the Texas Forest...

  6. Determining effective riparian buffer width for nonnative plant exclusion and habitat enhancement

    Science.gov (United States)

    Gavin Ferris; Vincent D' Amico; Christopher K. Williams

    2012-01-01

    Nonnative plants threaten native biodiversity in landscapes where habitats are fragmented. Unfortunately, in developed areas, much of the remaining forested habitat occurs in fragmented riparian corridors. Because forested corridors of sufficient width may allow forest interior specializing native species to retain competitive advantage over edge specialist and...

  7. Germination responses of an invasive species in native and non-native ranges

    Science.gov (United States)

    Jose L. Hierro; Ozkan Eren; Liana Khetsuriani; Alecu Diaconu; Katalin Torok; Daniel Montesinos; Krikor Andonian; David Kikodze; Levan Janoian; Diego Villarreal; Maria Estanga-Mollica; Ragan M. Callaway

    2009-01-01

    Studying germination in the native and non-native range of a species can provide unique insights into processes of range expansion and adaptation; however, traits related to germination have rarely been compared between native and nonnative populations. In a series of common garden experiments, we explored whether differences in the seasonality of precipitation,...

  8. Symbiosis in the Context of an Invasive, Non-Native Grass: Fungal Biodiversity and Student Engagement

    Science.gov (United States)

    Lehr, Gavin

    Grasslands in the western United States face severe environmental threats including those brought about by climate change, such as changes in precipitation regimes and altered fire cycles; land-use conversion and development; and the introduction, establishment, and spread of non-native species. Lehmann's lovegrass (Eragrostis lehmanniana) was introduced to the southwestern United States in the early 1900s. Since its introduction, it has become the dominant grass in the mid-elevation grasslands of southern Arizona, including the Santa Rita Experimental Range (SRER), where it has displaced native grasses including Arizona cottontop, three awns, and gramas. Like all plants in terrestrial ecosystems, this grass harbors fungal symbionts that can be important for its establishment and persistence. This thesis focuses on fungal symbionts of Lehmann's lovegrass and has two components. First, the diversity and distributions of endophytes in Lehmann's lovegrass are evaluated in the context of biotic and abiotic factors in the SRER. Culturing from roots and shoots of Lehmann's lovegrass at points beneath and outside the canopy of native mesquites, which are encroaching on grasslands over time, provides insight into how a single plant species can exhibit local variation in the composition of its symbionts. Second, the thesis is used as the basis for engagement of students in science, technology, engineering, and mathematics (STEM) through the development and implementation of classroom- and field activities centered on endophytes, which help high school students address core learning aims while also gaining real research experience. Engaging students in important questions relevant to their local environment can catalyze interest in science and help students cross the threshold into research. The contributions of such approaches with respect to learning not only fulfills key next-generation science standards and common core objectives, but provides students with a meaningful

  9. Native and non-native plants provide similar refuge to invertebrate prey, but less than artificial plants

    NARCIS (Netherlands)

    Grutters, Bart; Pollux, B.J.A.; Verberk, W.C.E.P.; Bakker, E.S.

    2015-01-01

    Non-native species introductions are widespread and can affect ecosystem functioning by altering the structure of food webs. Invading plants often modify habitat structure, which may affect the suitability of vegetation as refuge and could thus impact predator-prey dynamics. Yet little is known

  10. When perception reflects reality: Non-native grass invasion alters small mammal risk landscapes and survival

    Science.gov (United States)

    Ceradnini, Joseph P.; Chalfoun, Anna

    2017-01-01

    Modification of habitat structure due to invasive plants can alter the risk landscape for wildlife by, for example, changing the quality or availability of refuge habitat. Whether perceived risk corresponds with actual fitness outcomes, however, remains an important open question. We simultaneously measured how habitat changes due to a common invasive grass (cheatgrass, Bromus tectorum) affected the perceived risk, habitat selection, and apparent survival of a small mammal, enabling us to assess how well perceived risk influenced important behaviors and reflected actual risk. We measured perceived risk by nocturnal rodents using a giving-up density foraging experiment with paired shrub (safe) and open (risky) foraging trays in cheatgrass and native habitats. We also evaluated microhabitat selection across a cheatgrass gradient as an additional assay of perceived risk and behavioral responses for deer mice (Peromyscus maniculatus) at two spatial scales of habitat availability. Finally, we used mark-recapture analysis to quantify deer mouse apparent survival across a cheatgrass gradient while accounting for detection probability and other habitat features. In the foraging experiment, shrubs were more important as protective cover in cheatgrass-dominated habitats, suggesting that cheatgrass increased perceived predation risk. Additionally, deer mice avoided cheatgrass and selected shrubs, and marginally avoided native grass, at two spatial scales. Deer mouse apparent survival varied with a cheatgrass–shrub interaction, corresponding with our foraging experiment results, and providing a rare example of a native plant mediating the effects of an invasive plant on wildlife. By synthesizing the results of three individual lines of evidence (foraging behavior, habitat selection, and apparent survival), we provide a rare example of linkage between behavioral responses of animals indicative of perceived predation risk and actual fitness outcomes. Moreover, our results

  11. Projecting invasion risk of non-native watersnakes (Nerodia fasciata and Nerodia sipedon in the western United States.

    Directory of Open Access Journals (Sweden)

    Jonathan P Rose

    Full Text Available Species distribution models (SDMs are increasingly used to project the potential distribution of introduced species outside their native range. Such studies rarely explicitly evaluate potential conflicts with native species should the range of introduced species expand. Two snake species native to eastern North America, Nerodia fasciata and Nerodia sipedon, have been introduced to California where they represent a new stressor to declining native amphibians, fish, and reptiles. To project the potential distributions of these non-native watersnakes in western North America, we built ensemble SDMs using MaxEnt, Boosted Regression Trees, and Random Forests and habitat and climatic variables. We then compared the overlap between the projected distribution of invasive watersnakes and the distributions of imperiled native amphibians, fish, and reptiles that can serve as prey or competitors for the invaders, to estimate the risk to native species posed by non-native watersnakes. Large areas of western North America were projected to be climatically suitable for both species of Nerodia according to our ensemble SDMs, including much of central California. The potential distributions of both N. fasciata and N. sipedon overlap extensively with the federally threatened Giant Gartersnake, Thamnophis gigas, which inhabits a similar ecological niche. N. fasciata also poses risk to the federally threatened California Tiger Salamander, Ambystoma californiense, whereas N. sipedon poses risk to some amphibians of conservation concern, including the Foothill Yellow-legged Frog, Rana boylii. We conclude that non-native watersnakes in California can likely inhabit ranges of several native species of conservation concern that are expected to suffer as prey or competing species for these invaders. Action should be taken now to eradicate or control these invasions before detrimental impacts on native species are widespread. Our methods can be applied broadly to quantify

  12. Invasive plant species in hardwood tree plantations

    Science.gov (United States)

    Rochelle R. Beasley; Paula M. Pijut

    2010-01-01

    Invasive plants are species that can grow and spread aggressively, mature quickly, and invade an ecosystem causing economic and environmental damage. Invasive plants usually invade disturbed areas, but can also colonize small areas quickly, and may spread and dominate large areas in a few short years. Invasive plant species displace native or desirable forest...

  13. Global exchange and accumulation of non-native plants

    Czech Academy of Sciences Publication Activity Database

    van Kleunen, M.; Dawson, W.; Essl, F.; Pergl, Jan; Winter, M.; Weber, E.; Kreft, H.; Weigelt, P.; Kartesz, J.; Nishino, M.; Antonova, L. A.; Barcelona, J. F.; Cabezas, F. J.; Cardenas, D.; Cardenas-Toro, J.; Castano, N.; Chacon, E.; Chatelain, C.; Ebel, A. L.; Figueiredo, E.; Fuentes, N.; Groom, Q. J.; Henderson, L.; Inderjit, Dr.; Kupriyanov, A.; Masciadri, S.; Meerman, J.; Morozova, O.; Moser, D.; Nickrent, D. L.; Patzelt, A.; Pelser, P. B.; Baptiste, M. P.; Poopath, M.; Schulze, M.; Seebens, H.; Shu, W.-S.; Thomas, J.; Velayos, M.; Wieringa, J. J.; Pyšek, Petr

    2015-01-01

    Roč. 525, č. 7567 (2015), s. 100-103 ISSN 0028-0836 R&D Projects: GA ČR GB14-36079G Grant - others:AV ČR(CZ) AP1002 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985939 Keywords : biological invasions * anthropocene * perspectives Subject RIV: EH - Ecology, Behaviour Impact factor: 38.138, year: 2015

  14. Characterizing the landscape dynamics of an invasive plant and risk of invasion using remote sensing.

    Science.gov (United States)

    Bradley, Bethany A; Mustard, John F

    2006-06-01

    Improved understanding of the spatial dynamics of invasive plant species may lead to more effective land management and reduced future invasion. Here, we identified the spatial extents of nonnative cheatgrass (Bromus tectorum) in the north central Great Basin using remotely sensed data from Landsat MSS, TM, and ETM+. We compared cheatgrass extents in 1973 and 2001 to six spatially explicit landscape variables: elevation, aspect, hydrographic channels, cultivation, roads, and power lines. In 2001, Cheatgrass was 10% more likely to be found in elevation ranges from 1400 to 1700 m (although the data suggest a preferential invasion into lower elevations by 2001), 6% more likely on west and northwest facing slopes, and 3% more likely within hydrographic channels. Over this time period, cheatgrass expansion was also closely linked to proximity to land use. In 2001, cheatgrass was 20% more likely to be found within 3 km of cultivation, 13% more likely to be found within 700 m of a road, and 15% more likely to be found within 1 km of a power line. Finally, in 2001 cheatgrass was 26% more likely to be present within 150 m of areas occupied by cheatgrass in 1973. Using these relationships, we created a risk map of future cheatgrass invasion that may aid land management. These results highlight the importance of including land use variables and the extents of current plant invasion in predictions of future risk.

  15. Invasibility of Mediterranean-climate rivers by non-native fish: the importance of environmental drivers and human pressures.

    Directory of Open Access Journals (Sweden)

    Maria Ilhéu

    Full Text Available Invasive species are regarded as a biological pressure to natural aquatic communities. Understanding the factors promoting successful invasions is of great conceptual and practical importance. From a practical point of view, it should help to prevent future invasions and to mitigate the effects of recent invaders through early detection and prioritization of management measures. This study aims to identify the environmental determinants of fish invasions in Mediterranean-climate rivers and evaluate the relative importance of natural and human drivers. Fish communities were sampled in 182 undisturbed and 198 disturbed sites by human activities, belonging to 12 river types defined for continental Portugal within the implementation of the European Union's Water Framework Directive. Pumpkinseed sunfish, Lepomis gibbosus (L., and mosquitofish, Gambusia holbrooki (Girard, were the most abundant non-native species (NNS in the southern river types whereas the Iberian gudgeon, Gobio lozanoi Doadrio and Madeira, was the dominant NNS in the north/centre. Small northern mountain streams showed null or low frequency of occurrence and abundance of NNS, while southern lowland river types with medium and large drainage areas presented the highest values. The occurrence of NNS was significantly lower in undisturbed sites and the highest density of NNS was associated with high human pressure. Results from variance partitioning showed that natural environmental factors determine the distribution of the most abundant NNS while the increase in their abundance and success is explained mainly by human-induced disturbance factors. This study stresses the high vulnerability of the warm water lowland river types to non-native fish invasions, which is amplified by human-induced degradation.

  16. Vulnerability of freshwater native biodiversity to non-native species invasions across the continental United States

    Science.gov (United States)

    Background/Question/Methods Non-native species pose one of the greatest threats to native biodiversity. The literature provides plentiful empirical and anecdotal evidence of this phenomenon; however, such evidence is limited to local or regional scales. Employing geospatial analy...

  17. Invasive Plants on Rangelands: a Global Threat

    Science.gov (United States)

    Invasive plant species are spreading and invading rangelands at an unprecedented rate costing ranchers billions of dollars to control invasive plants each year. In its simplest form, the invasion process has four primary stages, including introduction, establishment, spread and colonization. Th...

  18. Do invasive plant species alter soil health?

    Science.gov (United States)

    Invasive species may alter soil characteristics or interact with the soil microbial community to yield a competitive advantage. Our objectives were to determine: if invasive plant species alter soil properties important to soil health; and the long-term effects of invasive plant species on soil pro...

  19. Plant-soil biota interactions and spatial distribution of black cherry in its native and invasive ranges

    NARCIS (Netherlands)

    Reinhart, K.O.; Packer, A.; Van der Putten, W.H.; Clay, K.A.

    2003-01-01

    One explanation for the higher abundance of invasive species in their non-native than native ranges is the escape from natural enemies. But there are few experimental studies comparing the parallel impact of enemies (or competitors and mutualists) on a plant species in its native and invaded ranges,

  20. Presence and abundance of non-native plant species associated with recent energy development in the Williston Basin

    Science.gov (United States)

    Preston, Todd M.

    2015-01-01

    The Williston Basin, located in the Northern Great Plains, is experiencing rapid energy development with North Dakota and Montana being the epicenter of current and projected development in the USA. The average single-bore well pad is 5 acres with an estimated 58,485 wells in North Dakota alone. This landscape-level disturbance may provide a pathway for the establishment of non-native plants. To evaluate potential influences of energy development on the presence and abundance of non-native species, vegetation surveys were conducted at 30 oil well sites (14 ten-year-old and 16 five-year-old wells) and 14 control sites in native prairie environments across the Williston Basin. Non-native species richness and cover were recorded in four quadrats, located at equal distances, along four transects for a total of 16 quadrats per site. Non-natives were recorded at all 44 sites and ranged from 5 to 13 species, 7 to 15 species, and 2 to 8 species at the 10-year, 5-year, and control sites, respectively. Respective non-native cover ranged from 1 to 69, 16 to 76, and 2 to 82 %. Total, forb, and graminoid non-native species richness and non-native forb cover were significantly greater at oil well sites compared to control sites. At oil well sites, non-native species richness and forb cover were significantly greater adjacent to the well pads and decreased with distance to values similar to control sites. Finally, non-native species whose presence and/or abundance were significantly greater at oil well sites relative to control sites were identified to aid management efforts.

  1. Fungal endophytes from seeds of invasive, non-native Phragmites australis and their potential role in germination and seedling growth

    Science.gov (United States)

    Shearin, Zackery R. C.; Filipek, Matthew; Desai, Rushvi; Bickford, Wesley A.; Kowalski, Kurt P.; Clay, Keith

    2018-01-01

    Background and aimsWe characterized fungal endophytes of seeds of invasive, non-native Phragmites from three sites in the Great Lakes region to determine if fungal symbiosis could contribute to invasiveness through their effects on seed germination and seedling growth.MethodsField-collected seeds were surface sterilized and plated on agar to culture endophytes for ITS sequencing. Prevalence of specific endophytes from germinated and non-germinated seeds, and from seedlings, was compared.ResultsOne-third of 740 seeds yielded endophyte isolates. Fifteen taxa were identified with Alternaria sp. representing 54% of all isolates followed by Phoma sp. (21%) and Penicillium corylophilum (12%). Overall germination of seeds producing an isolate (36%) was significantly higher than seeds not producing an isolate (20%). Penicillium in particular was strongly associated with increased germination of seeds from one site. Sixty-three isolates and 11 taxa were also obtained from 30 seedlings where Phoma, Penicillium and Alternaria respectively were most prevalent. There was a significant effect of isolating an endophyte from the seed on seedling growth.ConclusionsThese results suggest that many endophyte taxa are transmitted in seeds and can increase seed germination and seedling growth of invasive Phragmites. The role of fungal endophytes in host establishment, growth and invasiveness in nature requires further research.

  2. Effects of fire on fish populations: Landscape perspectives on persistance of native fishes and nonnative fish invasions

    Science.gov (United States)

    Dunham, J.B.; Young, M.; Gresswell, Robert E.; Rieman, B.

    2003-01-01

    Our limited understanding of the short and long-term effects of fire on fish contributes to considerable uncertainty in assessments of the risks and benefits of fire management alternatives. A primary concern among the many potential effects of fire is the effects of fire and fire management on persistence of native fish populations. Limited evidence suggests vulnerability of fish to fire is contingent upon the quality of affected habitats, the amount and distribution of habitat (habitat fragmentation), and habitat specificity of the species in question. Species with narrow habitat requirements in highly degraded and fragmented systems are likely to be most vulnerable to fire and fire-related disturbance. In addition to effects of fire on native fish, there are growing concerns about the effects of fire on nonnative fish invasions. The role of fire in facilitating invasions by nonnative fishes is unknown, but experience with other species suggests some forms of disturbance associated with fire may facilitate invasion. Management efforts to promote persistence of fishes in fire-prone landscapes can take the form of four basic alternatives: (1) pre-fire management; (2) post-fire management; (3) managing fire itself (e.g. fire fighting); and (4) monitoring and adaptive management. Among these alternatives, pre-fire management is likely to be most effective. Effective pre-fire management activities will address factors that may render fish populations more vulnerable to the effects of fire (e.g. habitat degradation, fragmentation, and nonnative species). Post-fire management is also potentially important, but suffers from being a reactive approach that may not address threats in time to avert them. Managing fire itself can be important in some contexts, but negative consequences for fish populations are possible (e.g. toxicity of fire fighting chemicals to fish). Monitoring and adaptive management can provide important new information for evaluating alternatives, but

  3. Competition overwhelms the positive plant-soil feedback generated by an invasive plant.

    Science.gov (United States)

    Crawford, Kerri M; Knight, Tiffany M

    2017-01-01

    Invasive plant species can modify soils in a way that benefits their fitness more than the fitness of native species. However, it is unclear how competition among plant species alters the strength and direction of plant-soil feedbacks. We tested how community context altered plant-soil feedback between the non-native invasive forb Lespedeza cuneata and nine co-occurring native prairie species. In a series of greenhouse experiments, we grew plants individually and in communities with soils that differed in soil origin (invaded or uninvaded by L. cuneata) and in soils that were live vs. sterilized. In the absence of competition, L. cuneata produced over 60% more biomass in invaded than uninvaded soils, while native species performance was unaffected. The absence of a soil origin effect in sterile soil suggests that the positive plant-soil feedback was caused by differences in the soil biota. However, in the presence of competition, the positive effect of soil origin on L. cuneata growth disappeared. These results suggest that L. cuneata may benefit from positive plant-soil feedback when establishing populations in disturbed landscapes with few interspecific competitors, but does not support the hypothesis that plant-soil feedbacks influence competitive outcomes between L. cuneata and native plant species. These results highlight the importance of considering whether competition influences the outcome of interactions between plants and soils.

  4. Direct and Indirect Influence of Non-Native Neighbours on Pollination and Fruit Production of a Native Plant.

    Directory of Open Access Journals (Sweden)

    Ana Montero-Castaño

    Full Text Available Entomophilous non-native plants can directly affect the pollination and reproductive success of native plant species and also indirectly, by altering the composition and abundance of floral resources in the invaded community. Separating direct from indirect effects is critical for understanding the mechanisms underlying the impacts of non-native species on recipient communities.Our aims are: (a to explore both the direct effect of the non-native Hedysarum coronarium and its indirect effect, mediated by the alteration of floral diversity, on the pollinator visitation rate and fructification of the native Leopoldia comosa and (b to distinguish whether the effects of the non-native species were due to its floral display or to its vegetative interactions.We conducted field observations within a flower removal experimental setup (i.e. non-native species present, absent and with its inflorescences removed at the neighbourhood scale.Our study illustrates the complexity of mechanisms involved in the impacts of non-native species on native species. Overall, Hedysarum increased pollinator visitation rates to Leopoldia target plants as a result of direct and indirect effects acting in the same direction. Due to its floral display, Hedysarum exerted a direct magnet effect attracting visits to native target plants, especially those made by the honeybee. Indirectly, Hedysarum also increased the visitation rate of native target plants. Due to the competition for resources mediated by its vegetative parts, it decreased floral diversity in the neighbourhoods, which was negatively related to the visitation rate to native target plants. Hedysarum overall also increased the fructification of Leopoldia target plants, even though such an increase was the result of other indirect effects compensating for the observed negative indirect effect mediated by the decrease of floral diversity.

  5. Unconventional gas development facilitates plant invasions.

    Science.gov (United States)

    Barlow, Kathryn M; Mortensen, David A; Drohan, Patrick J; Averill, Kristine M

    2017-11-01

    Vegetation removal and soil disturbance from natural resource development, combined with invasive plant propagule pressure, can increase vulnerability to plant invasions. Unconventional oil and gas development produces surface disturbance by way of well pad, road, and pipeline construction, and increased traffic. Little is known about the resulting impacts on plant community assembly, including the spread of invasive plants. Our work was conducted in Pennsylvania forests that overlay the Marcellus and Utica shale formations to determine if invasive plants have spread to edge habitat created by unconventional gas development and to investigate factors associated with their presence. A piecewise structural equation model was used to determine the direct and indirect factors associated with invasive plant establishment on well pads. The model included the following measured or calculated variables: current propagule pressure on local access roads, the spatial extent of the pre-development road network (potential source of invasive propagules), the number of wells per pad (indicator of traffic density), and pad age. Sixty-one percent of the 127 well pads surveyed had at least one invasive plant species present. Invasive plant presence on well pads was positively correlated with local propagule pressure on access roads and indirectly with road density pre-development, the number of wells, and age of the well pad. The vast reserves of unconventional oil and gas are in the early stages of development in the US. Continued development of this underground resource must be paired with careful monitoring and management of surface ecological impacts, including the spread of invasive plants. Prioritizing invasive plant monitoring in unconventional oil and gas development areas with existing roads and multi-well pads could improve early detection and control of invasive plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Housing is positively associated with invasive exotic plant species richness in New England, USA.

    Science.gov (United States)

    Gavier-Pizarro, Gregorio I; Radeloff, Volker C; Stewart, Susan I; Huebner, Cynthia D; Keuler, Nicholas S

    2010-10-01

    Understanding the factors related to invasive exotic species distributions at broad spatial scales has important theoretical and management implications, because biological invasions are detrimental to many ecosystem functions and processes. Housing development facilitates invasions by disturbing land cover, introducing nonnative landscaping plants, and facilitating dispersal of propagules along roads. To evaluate relationships between housing and the distribution of invasive exotic plants, we asked (1) how strongly is housing associated with the spatial distribution of invasive exotic plants compared to other anthropogenic and environmental factors; (2) what type of housing pattern is related to the richness of invasive exotic plants; and (3) do invasive plants represent ecological traits associated with specific housing patterns? Using two types of regression analysis (best subset analysis and hierarchical partitioning analysis), we found that invasive exotic plant richness was equally or more strongly related to housing variables than to other human (e.g., mean income and roads) and environmental (e.g., topography and forest cover) variables at the county level across New England. Richness of invasive exotic plants was positively related to area of wildland-urban interface (WUI), low-density residential areas, change in number of housing units between 1940 and 2000, mean income, plant productivity (NDVI), and altitudinal range and rainfall; it was negatively related to forest area and connectivity. Plant life history traits were not strongly related to housing patterns. We expect the number of invasive exotic plants to increase as a result of future housing growth and suggest that housing development be considered a primary factor in plans to manage and monitor invasive exotic plant species.

  7. The Invasive Plant Species Education Guide

    Science.gov (United States)

    Mason, Kevin; James, Krista; Carlson, Kitrina; D'Angelo, Jean

    2010-01-01

    To help high school students gain a solid understanding of invasive plant species, university faculty and students from the University of Wisconsin-Stout (UW-Stout) and a local high school teacher worked together to develop the Invasive Plant Species (IPS) Education Guide. The IPS Education Guide includes nine lessons that give students an…

  8. Principles for ecologically based invasive plant management

    Science.gov (United States)

    Jeremy J. James; Brenda S. Smith; Edward A. Vasquez; Roger L. Sheley

    2010-01-01

    Land managers have long identified a critical need for a practical and effective framework for designing restoration strategies, especially where invasive plants dominate. A holistic, ecologically based, invasive plant management (EBIPM) framework that integrates ecosystem health assessment, knowledge of ecological processes, and adaptive management into a successional...

  9. Co-occurring nonnative woody shrubs have additive and non-additive soil legacies.

    Science.gov (United States)

    Kuebbing, Sara E; Patterson, Courtney M; Classen, Aimée T; Simberloff, Daniel

    2016-09-01

    To maximize limited conservation funds and prioritize management projects that are likely to succeed, accurate assessment of invasive nonnative species impacts is essential. A common challenge to prioritization is a limited knowledge of the difference between the impacts of a single nonnative species compared to the impacts of nonnative species when they co-occur, and in particular predicting when impacts of co-occurring nonnative species will be non-additive. Understanding non-additivity is important for management decisions because the management of only one co-occurring invader will not necessarily lead to a predictable reduction in the impact or growth of the other nonnative plant. Nonnative plants are frequently associated with changes in soil biotic and abiotic characteristics, which lead to plant-soil interactions that influence the performance of other species grown in those soils. Whether co-occurring nonnative plants alter soil properties additively or non-additively relative to their effects on soils when they grow in monoculture is rarely addressed. We use a greenhouse plant-soil feedback experiment to test for non-additive soil impacts of two common invasive nonnative woody shrubs, Lonicera maackii and Ligustrum sinense, in deciduous forests of the southeastern United States. We measured the performance of each nonnative shrub, a native herbaceous community, and a nonnative woody vine in soils conditioned by each shrub singly or together in polyculture. Soils conditioned by both nonnative shrubs had non-additive impacts on native and nonnative performance. Root mass of the native herbaceous community was 1.5 times lower and the root mass of the nonnative L. sinense was 1.8 times higher in soils conditioned by both L. maackii and L. sinense than expected based upon growth in soils conditioned by either shrub singly. This result indicates that when these two nonnative shrubs co-occur, their influence on soils disproportionally favors persistence

  10. A nonnative and a native fungal plant pathogen similarly stimulate ectomycorrhizal development but are perceived differently by a fungal symbiont.

    Science.gov (United States)

    Zampieri, Elisa; Giordano, Luana; Lione, Guglielmo; Vizzini, Alfredo; Sillo, Fabiano; Balestrini, Raffaella; Gonthier, Paolo

    2017-03-01

    The effects of plant symbionts on host defence responses against pathogens have been extensively documented, but little is known about the impact of pathogens on the symbiosis and if such an impact may differ for nonnative and native pathogens. Here, this issue was addressed in a study of the model system comprising Pinus pinea, its ectomycorrhizal symbiont Tuber borchii, and the nonnative and native pathogens Heterobasidion irregulare and Heterobasidion annosum, respectively. In a 6-month inoculation experiment and using both in planta and gene expression analyses, we tested the hypothesis that H. irregulare has greater effects on the symbiosis than H. annosum. Although the two pathogens induced the same morphological reaction in the plant-symbiont complex, with mycorrhizal density increasing exponentially with pathogen colonization of the host, the number of target genes regulated in T. borchii in plants inoculated with the native pathogen (i.e. 67% of tested genes) was more than twice that in plants inoculated with the nonnative pathogen (i.e. 27% of genes). Although the two fungal pathogens did not differentially affect the amount of ectomycorrhizas, the fungal symbiont perceived their presence differently. The results may suggest that the symbiont has the ability to recognize a self/native and a nonself/nonnative pathogen, probably through host plant-mediated signal transduction. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  11. Do non-native plant species affect the shape of productivity-diversity relationships?

    Science.gov (United States)

    Drake, J.M.; Cleland, E.E.; Horner-Devine, M. C.; Fleishman, E.; Bowles, C.; Smith, M.D.; Carney, K.; Emery, S.; Gramling, J.; Vandermast, D.B.; Grace, J.B.

    2008-01-01

    The relationship between ecosystem processes and species richness is an active area of research and speculation. Both theoretical and experimental studies have been conducted in numerous ecosystems. One finding of these studies is that the shape of the relationship between productivity and species richness varies considerably among ecosystems and at different spatial scales, though little is known about the relative importance of physical and biological mechanisms causing this variation. Moreover, despite widespread concern about changes in species' global distributions, it remains unclear if and how such large-scale changes may affect this relationship. We present a new conceptual model of how invasive species might modulate relationships between primary production and species richness. We tested this model using long-term data on relationships between aboveground net primary production and species richness in six North American terrestrial ecosystems. We show that primary production and abundance of non-native species are both significant predictors of species richness, though we fail to detect effects of invasion extent on the shapes of the relationship between species richness and primary production.

  12. Riparian Vegetation Response to the March 2008 Short-Duration, High-Flow Experiment-Implications of Timing and Frequency of Flood Disturbance on Nonnative Plant Establishment Along the Colorado River Below Glen Canyon Dam

    Science.gov (United States)

    Ralston, Barbara E.

    2010-01-01

    Riparian plant communities exhibit various levels of diversity and richness. These communities are affected by flooding and are vulnerable to colonization by nonnative species. Since 1996, a series of three high-flow experiments (HFE), or water releases designed to mimic natural seasonal flooding, have been conducted at Glen Canyon Dam, Ariz., primarily to determine the effectiveness of using high flows to conserve sediment, a limited resource. These experiments also provide opportunities to examine the susceptibility of riparian plant communities to nonnative species invasions. The third and most recent HFE was conducted from March 5 to 9, 2008, and scientists with the U.S. Geological Survey's Grand Canyon Monitoring and Research Center examined the effects of high flows on riparian vegetation as part of the overall experiment. Total plant species richness, nonnative species richness, percent plant cover, percent organic matter, and total carbon measured from sediment samples were compared for Grand Canyon riparian vegetation zones immediately following the HFE and 6 months later. These comparisons were used to determine if susceptibility to nonnative species establishment varied among riparian vegetation zones and if the timing of the HFE affected nonnative plant establishment success. The 2008 HFE primarily buried vegetation rather than scouring it. Percent nonnative cover did not differ among riparian vegetation zones; however, in the river corridor affected by Glen Canyon Dam operations, nonnative species richness showed significant variation. For example, species richness was significantly greater immediately after and 6 months following the HFE in the hydrologic zone farthest away from the shoreline, the area that represents the oldest riparian zone within the post-dam riparian area. In areas closer to the river channel, tamarisk (Tamarix ramosissima X chinensis) seedling establishment occurred (tamarisk seed production, or in 1986, a year following several

  13. Plant invasions: Merging the concepts of species invasiveness and community invasibility

    Czech Academy of Sciences Publication Activity Database

    Richardson, D. M.; Pyšek, Petr

    2006-01-01

    Roč. 30, č. 3 (2006), s. 409-431 ISSN 0309-1333 Institutional research plan: CEZ:AV0Z60050516 Keywords : plant invasions * species invasiveness * community invasibility Subject RIV: EF - Botanics Impact factor: 1.278, year: 2006

  14. Analysis of trade-offs between threats of invasion by nonnative brook trout (Salvelinus fontinalis) and intentional isolation for native westslope cutthroat trout (Oncorhynchus clarkii lewisi)

    Science.gov (United States)

    Peterson, D.P.; Rieman, B.E.; Dunham, J.B.; Fausch, K.D.; Young, M.K.

    2008-01-01

    Native salmonid fishes often face simultaneous threats from habitat fragmentation and invasion by nonnative trout species. Unfortunately, management actions to address one may create or exacerbate the other. A consistent decision process would include a systematic analysis of when and where intentional use or removal of barriers is the most appropriate action. We developed a Bayesian belief network as a tool for such analyses. We focused on native westslope cutthroat trout (Oncorhynchus clarkii lewisi) and nonnative brook trout (Salvelinus fontinalis) and considered the environmental factors influencing both species, their potential interactions, and the effects of isolation on the persistence of local cutthroat trout populations. The trade-offs between isolation and invasion were strongly influenced by size and habitat quality of the stream network to be isolated and existing demographic linkages within and among populations. An application of the model in several sites in western Montana (USA) showed the process could help clarify management objectives and options and prioritize conservation actions among streams. The approach can also facilitate communication among parties concerned with native salmonids, nonnative fish invasions, barriers and intentional isolation, and management of the associated habitats and populations. ?? 2008 NRC.

  15. Ecosystem services in the face of invasion: the persistence of native and nonnative spiders in an agricultural landscape.

    Science.gov (United States)

    Hogg, Brian N; Daane, Kent M

    2011-03-01

    The presence of intact natural ecosystems in agricultural landscapes can mitigate losses in the diversity of natural enemies and enhance ecosystem services. However, native natural enemies may fail to persist in agroecosystems if invaders dominate species interactions. In this study, native and nonnative spiders were sampled along transects that extended from oak woodland and riparian zones into surrounding California vineyards, to assess the role of natural habitat as a source for spider biodiversity in the vineyard landscape, and to compare the dominance of exotic Cheiracanthium spiders between habitats. Many spider species were more abundant in natural habitat than in vineyards, and numbers of spiders and spider species within vineyards were higher at the vineyard edge adjacent to oak woodland. These results suggest that natural habitat is a key source for spiders in vineyards. The positive effect of oak woodland on the vineyard spider community extended only to the vineyard edge, however. Proportions of Cheiracanthium spiders increased dramatically in the vineyard, while numbers of native wandering spiders (the native ecological homologues of Cheiracanthium spiders) decreased. Dispersal limitation and strong habitat preferences may have prevented native wandering spiders from establishing far from the vineyard edge. Exotic Cheiracanthium spiders, in contrast, may possess specific adaptations to vineyards or to a wide range of habitats. Results suggest that the ecosystem services provided by intact natural habitat may be limited in agricultural landscapes that are dominated by invasive species.

  16. Can a native rodent species limit the invasive potential of a non-native rodent species in tropical agroforest habitats?

    Science.gov (United States)

    Stuart, Alexander M; Prescott, Colin V; Singleton, Grant R

    2016-06-01

    Little is known about native and non-native rodent species interactions in complex tropical agroecosystems. We hypothesised that the native non-pest rodent Rattus everetti may be competitively dominant over the invasive pest rodent Rattus tanezumi within agroforests. We tested this experimentally by using pulse removal for three consecutive months to reduce populations of R. everetti in agroforest habitat, and assessed over 6 months the response of R. tanezumi and other rodent species. Following removal, R. everetti individuals rapidly immigrated into removal sites. At the end of the study period, R. tanezumi were larger and there was a significant shift in their microhabitat use with respect to the use of ground vegetation cover following the perturbation of R. everetti. Irrespective of treatment, R. tanezumi selected microhabitat with less tree canopy cover, indicative of severely disturbed habitat, whereas R. everetti selected microhabitat with a dense canopy. Our results suggest that sustained habitat disturbance in agroforests favours R. tanezumi, while the regeneration of agroforests towards a more natural state would favour native species and may reduce pest pressure in adjacent crops. In addition, the rapid recolonisation of R. everetti suggests this species would be able to recover from non-target impacts of short-term rodent pest control. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  17. The Public and Professionals Reason Similarly about the Management of Non-Native Invasive Species: A Quantitative Investigation of the Relationship between Beliefs and Attitudes

    Science.gov (United States)

    Fischer, Anke; Selge, Sebastian; van der Wal, René; Larson, Brendon M. H.

    2014-01-01

    Despite continued critique of the idea of clear boundaries between scientific and lay knowledge, the ‘deficit-model’ of public understanding of ecological issues still seems prevalent in discourses of biodiversity management. Prominent invasion biologists, for example, still argue that citizens need to be educated so that they accept scientists’ views on the management of non-native invasive species. We conducted a questionnaire-based survey with members of the public and professionals in invasive species management (n = 732) in Canada and the UK to investigate commonalities and differences in their perceptions of species and, more importantly, how these perceptions were connected to attitudes towards species management. Both native and non-native mammal and tree species were included. Professionals tended to have more extreme views than the public, especially in relation to nativeness and abundance of a species. In both groups, species that were perceived to be more abundant, non-native, unattractive or harmful to nature and the economy were more likely to be regarded as in need of management. While perceptions of species and attitudes towards management thus often differed between public and professionals, these perceptions were linked to attitudes in very similar ways across the two groups. This suggests that ways of reasoning about invasive species employed by professionals and the public might be more compatible with each other than commonly thought. We recommend that managers and local people engage in open discussion about each other’s beliefs and attitudes prior to an invasive species control programme. This could ultimately reduce conflict over invasive species control. PMID:25170957

  18. Plasticity to salinity and transgenerational effects in the nonnative shrub Baccharis halimifolia: Insights into an estuarine invasion.

    Science.gov (United States)

    Caño, Lidia; Fuertes-Mendizabal, Teresa; García-Baquero, Gonzalo; Herrera, Mercedes; González-Moro, M Begoña

    2016-05-01

    Abiotic constraints act as selection filters for plant invasion in stressful habitats. Adaptive phenotypic plasticity and transgenerational effects play a major role in colonization of heterogeneous habitats when the scale of environmental variation is smaller than that of gene flow. We investigated how plasticity and parental salinity conditions influence the performance of the invasive dioecious shrub Baccharis halimifolia, which replaces heterogeneous estuarine communities in Europe with monospecific and continuous stands. In two greenhouse experiments, we grew plants derived from seeds and cuttings collected through interspersed patches differing in edaphic salinity from an invasive population. We estimated parental environmental salinity from leaf Na(+) content in parental plants, and we measured fitness and ion homeostasis of the offspring grown in contrasting salinity conditions. Baccharis halimifolia tolerates high salinity but experiences drastic biomass reduction at moderate salinity. At moderate salinity, responses to salinity are affected by the parental salinity: flowering initiation in seedlings and male cuttings is positively correlated with parental leaf Na(+) content, and biomass is positively correlated with maternal leaf Na(+) in female cuttings and seedlings. Plant height, leaf production, specific leaf area, and ionic homeostasis at the low part of the gradient are also affected by parental salinity, suggesting enhanced shoot growth as parental salinity increases. Our results support plasticity to salinity and transgenerational effects as factors with great potential to contribute to the invasive ability of B. halimifolia through estuarine communities of high conservation value. © 2016 Botanical Society of America.

  19. Estimating Invasion Success by Non-Native Trees in a National Park Combining WorldView-2 Very High Resolution Satellite Data and Species Distribution Models

    Directory of Open Access Journals (Sweden)

    Antonio T. Monteiro

    2017-01-01

    Full Text Available Invasion by non-native tree species is an environmental and societal challenge requiring predictive tools to assess invasion dynamics. The frequent scale mismatch between such tools and on-ground conservation is currently limiting invasion management. This study aimed to reduce these scale mismatches, assess the success of non-native tree invasion and determine the environmental factors associated to it. A hierarchical scaling approach combining species distribution models (SDMs and satellite mapping at very high resolution (VHR was developed to assess invasion by Acacia dealbata in Peneda-Gerês National Park, the only national park in Portugal. SDMs were first used to predict the climatically suitable areas for A. dealdata and satellite mapping with the random-forests classifier was then applied to WorldView-2 very-high resolution imagery to determine whether A. dealdata had actually colonized the predicted areas (invasion success. Environmental attributes (topographic, disturbance and canopy-related differing between invaded and non-invaded vegetated areas were then analyzed. The SDM results indicated that most (67% of the study area was climatically suitable for A. dealbata invasion. The onset of invasion was documented to 1905 and satellite mapping highlighted that 12.6% of study area was colonized. However, this species had only colonized 62.5% of the maximum potential range, although was registered within 55.6% of grid cells that were considerable unsuitable. Across these areas, the specific success rate of invasion was mostly below 40%, indicating that A. dealbata invasion was not dominant and effective management may still be possible. Environmental attributes related to topography (slope, canopy (normalized difference vegetation index (ndvi, land surface albedo and disturbance (historical burnt area differed between invaded and non-invaded vegetated area, suggesting that landscape attributes may alter at specific locations with Acacia

  20. Early detection of invasive plants: principles and practices

    Science.gov (United States)

    Welch, Bradley A.; Geissler, Paul H.; Latham, Penelope

    2014-01-01

    Invasive plants infest an estimated 2.6 million acres of the 83 million acres managed by the National Park Service (NPS) in the United States. The consequences of these invasions present a significant challenge for the NPS to manage the agency’s natural resources “unimpaired for the enjoyment of future generations.” More NPS lands are infested daily despite diligent efforts to curtail the problem. Impacts from invasive species have been realized in most parks, resulting in an expressed need to control existing infestations and restore affected ecosystems. There is a growing urgency in the NPS and other resource management organizations to be proactive. The NPS I&M Program, in collaboration with the U.S. Geological Survey (USGS) Status and Trends Program, compiled this document to provide guidance and insight to parks and other natural areas engaged in developing early-detection monitoring protocols for invasive plants. While several rapid response frameworks exist, there is no consistent or comprehensive guidance informing the active detection of nonnative plants early in the invasion process. Early-detection was selected as a primary focus for invasive-species monitoring because, along with rapid response, it is a key strategy for successful management of invasive species. Eradication efforts are most successful on small infestations (that is less than 1 hectare) and become less successful as infestation size increases, to the point that eradication is unlikely for large (that is greater than 1,000 hectares) populations of invasive plants. This document provides guidance for natural resource managers wishing to detect invasive plants early through an active, directed monitoring program. It has a Quick-Start Guide to direct readers to specific chapters and text relevant to their needs. Decision trees and flow charts assist the reader in deciding what methods to choose and when to use them. This document is written in a modular format to accommodate use of

  1. Pollination ecology of the invasive tree tobacco Nicotiana glauca: comparisons across native and non-native ranges

    Directory of Open Access Journals (Sweden)

    Jeff Ollerton

    2012-10-01

    Full Text Available Interactions with pollinators are thought to play a significant role in determining whether plant species become invasive, and ecologically generalised species are predicted to be more likely to invade than more specialised species. Using published and unpublished data we assessed the floral biology and pollination ecology of the South American native Nicotiana glauca (Solanaceae which has become a significant invasive of semi-arid parts of the world. In regions where specialised bird pollinators are available, for example hummingbirds in California and sunbirds in South Africa and Israel, N. glauca interacts with these local pollinators and sets seed by both out-crossing and selfing. In areas where there are no such birds, such as the Canary Islands and Greece, abundant viable seed is set by selfing, facilitated by the shorter stigma-anther distance compared to plants in native populations. Surprisingly, in these areas without pollinating birds, the considerable nectar resources are only rarely exploited by other flower visitors such as bees or butterflies, either legitimately or by nectar robbing. We conclude that Nicotiana glauca is a successful invasive species outside of its native range, despite its functionally specialised hummingbird pollination system, because it has evolved to become more frequently self pollinating in areas where it is introduced. Its invasion success is not predictable from what is known of its interactions with pollinators in its home range.

  2. Positive feedback between mycorrhizal fungi and plants influences plant invasion success and resistance to invasion.

    Science.gov (United States)

    Zhang, Qian; Yang, Ruyi; Tang, Jianjun; Yang, Haishui; Hu, Shuijin; Chen, Xin

    2010-08-24

    Negative or positive feedback between arbuscular mycorrhizal fungi (AMF) and host plants can contribute to plant species interactions, but how this feedback affects plant invasion or resistance to invasion is not well known. Here we tested how alterations in AMF community induced by an invasive plant species generate feedback to the invasive plant itself and affect subsequent interactions between the invasive species and its native neighbors. We first examined the effects of the invasive forb Solidago canadensis L. on AMF communities comprising five different AMF species. We then examined the effects of the altered AMF community on mutualisms formed with the native legume forb species Kummerowia striata (Thunb.) Schindl. and on the interaction between the invasive and native plants. The host preferences of the five AMF were also assessed to test whether the AMF form preferred mutualistic relations with the invasive and/or the native species. We found that S. canadensis altered AMF spore composition by increasing one AMF species (Glomus geosporum) while reducing Glomus mosseae, which is the dominant species in the field. The host preference test showed that S. canadensis had promoted the abundance of AMF species (G. geosporum) that most promoted its own growth. As a consequence, the altered AMF community enhanced the competitiveness of invasive S. canadensis at the expense of K. striata. Our results demonstrate that the invasive S. canadensis alters soil AMF community composition because of fungal-host preference. This change in the composition of the AMF community generates positive feedback to the invasive S. canadensis itself and decreases AM associations with native K. striata, thereby making the native K. striata less dominant.

  3. Positive feedback between mycorrhizal fungi and plants influences plant invasion success and resistance to invasion.

    Directory of Open Access Journals (Sweden)

    Qian Zhang

    2010-08-01

    Full Text Available Negative or positive feedback between arbuscular mycorrhizal fungi (AMF and host plants can contribute to plant species interactions, but how this feedback affects plant invasion or resistance to invasion is not well known. Here we tested how alterations in AMF community induced by an invasive plant species generate feedback to the invasive plant itself and affect subsequent interactions between the invasive species and its native neighbors. We first examined the effects of the invasive forb Solidago canadensis L. on AMF communities comprising five different AMF species. We then examined the effects of the altered AMF community on mutualisms formed with the native legume forb species Kummerowia striata (Thunb. Schindl. and on the interaction between the invasive and native plants. The host preferences of the five AMF were also assessed to test whether the AMF form preferred mutualistic relations with the invasive and/or the native species. We found that S. canadensis altered AMF spore composition by increasing one AMF species (Glomus geosporum while reducing Glomus mosseae, which is the dominant species in the field. The host preference test showed that S. canadensis had promoted the abundance of AMF species (G. geosporum that most promoted its own growth. As a consequence, the altered AMF community enhanced the competitiveness of invasive S. canadensis at the expense of K. striata. Our results demonstrate that the invasive S. canadensis alters soil AMF community composition because of fungal-host preference. This change in the composition of the AMF community generates positive feedback to the invasive S. canadensis itself and decreases AM associations with native K. striata, thereby making the native K. striata less dominant.

  4. Bacterial endophytes enhance competition by invasive plants.

    Science.gov (United States)

    Rout, Marnie E; Chrzanowski, Thomas H; Westlie, Tara K; DeLuca, Thomas H; Callaway, Ragan M; Holben, William E

    2013-09-01

    Invasive plants can alter soil microbial communities and profoundly alter ecosystem processes. In the invasive grass Sorghum halepense, these disruptions are consequences of rhizome-associated bacterial endophytes. We describe the effects of N2-fixing bacterial strains from S. halepense (Rout and Chrzanowski, 2009) on plant growth and show that bacteria interact with the plant to alter soil nutrient cycles, enabling persistence of the invasive. • We assessed fluxes in soil nutrients for ∼4 yr across a site invaded by S. halepense. We assayed the N2-fixing bacteria in vitro for phosphate solubilization, iron chelation, and production of the plant-growth hormone indole-3-acetic acid (IAA). We assessed the plant's ability to recruit bacterial partners from substrates and vertically transmit endophytes to seeds and used an antibiotic approach to inhibit bacterial activity in planta and assess microbial contributions to plant growth. • We found persistent alterations to eight biogeochemical cycles (including nitrogen, phosphorus, and iron) in soils invaded by S. halepense. In this context, three bacterial isolates solubilized phosphate, and all produced iron siderophores and IAA in vitro. In growth chamber experiments, bacteria were transmitted vertically, and molecular analysis of bacterial community fingerprints from rhizomes indicated that endophytes are also horizontally recruited. Inhibiting bacterial activity with antibiotics resulted in significant declines in plant growth rate and biomass, with pronounced rhizome reductions. • This work suggests a major role of endophytes on growth and resource allocation of an invasive plant. Indeed, bacterial isolate physiology is correlated with invader effects on biogeochemical cycles of nitrogen, phosphate, and iron.

  5. Alien plant invasions in European woodlands

    NARCIS (Netherlands)

    Wagner, Viktoria; Chytrý, Milan; Jiménez-Alfaro, Borja; Pergl, Jan; Hennekens, Stephan; Biurrun, Idoia; Knollová, Ilona; Berg, Christian; Vassilev, Kiril; Rodwell, John S.; Škvorc, Željko; Jandt, Ute; Ewald, Jörg; Jansen, Florian; Tsiripidis, Ioannis; Botta-Dukát, Zoltán; Casella, Laura; Attorre, Fabio; Rašomavičius, Valerijus; Ćušterevska, Renata; Schaminée, Joop H.J.; Brunet, Jörg; Lenoir, Jonathan; Svenning, Jens Christian; Kącki, Zygmunt; Petrášová-Šibíková, Mária; Šilc, Urban; García-Mijangos, Itziar; Campos, Juan Antonio; Fernández-González, Federico; Wohlgemuth, Thomas; Onyshchenko, Viktor; Pyšek, Petr

    2017-01-01

    Aim: Woodlands make up a third of European territory and carry out important ecosystem functions, yet a comprehensive overview of their invasion by alien plants has never been undertaken across this continent. Location: Europe. Methods: We extracted data from 251,740 vegetation plots stored in the

  6. Does responsiveness to arbuscular mycorrhizas depend on plant invasive status?

    Science.gov (United States)

    1. Some posit invasive alien plants are less dependent on mycorrhizal associations than native plants, and thus weak mycorrhizal responsiveness may be a general mechanism of plant invasion. 2. Here, we tested whether mycorrhizal responsiveness varies by plant invasive status while controlling for ph...

  7. Interactions between exotic invasive plants and soil microbes in the rhizosphere suggest that 'everything is not everywhere'.

    Science.gov (United States)

    Rout, Marnie E; Callaway, Ragan M

    2012-07-01

    The study of soil biota in the context of exotic plant invasions has led to an explosion in our understanding of the ecological roles of many different groups of microbes that function in roots or at the root-soil interface. Part of this progress has been the emergence of two biogeographic patterns involving invasive plants and soil microbes. First, in their non-native ranges invasive plants commonly interact differently with the same soil microbes than native plants. Second, in their native ranges, plants that are invasive elsewhere commonly interact functionally with soil microbes differently in their home ranges than they do in their non-native ranges. These studies pose a challenge to a long-held paradigm about microbial biogeography - the idea that microbes are not limited by dispersal and are thus free from the basic taxonomic, biogeographical and evolutionary framework that characterizes all other life on Earth. As an analogy, the global distribution of animals that function as carnivores does not negate the fascinating evolutionary biogeographic patterns of carnivores. Other challenges to this notion come from new measurements of genetic differences among microbes across geographic boundaries, which also suggest that meaningful biogeographic patterns exist for microorganisms. We expand this discussion of whether or not 'everything is everywhere' by using the inherently biogeographic context of plant invasions by reviewing the literature on interactions among invasive plants and the microorganisms in the rhizosphere. We find that these interactions can be delineated at multiple scales: from individual plants to continents. Thus the microbes that regulate major aspects of plant biology do not appear to be exempt from the fundamental evolutionary processes of geographical isolation and natural selection. At the important scales of taxonomy, ecotype and ecosystem functions, the fundamental ecology of invaders and soil microbes indicates that everything might

  8. Contrasting effects of specialist and generalist herbivores on resistance evolution in invasive plants.

    Science.gov (United States)

    Zhang, Zhijie; Pan, Xiaoyun; Blumenthal, Dana; van Kleunen, Mark; Liu, Mu; Li, Bo

    2018-04-01

    Invasive alien plants are likely to be released from specialist herbivores and at the same time encounter biotic resistance from resident generalist herbivores in their new ranges. The Shifting Defense hypothesis predicts that this will result in evolution of decreased defense against specialist herbivores and increased defense against generalist herbivores. To test this, we performed a comprehensive meta-analysis of 61 common garden studies that provide data on resistance and/or tolerance for both introduced and native populations of 32 invasive plant species. We demonstrate that introduced populations, relative to native populations, decreased their resistance against specialists, and increased their resistance against generalists. These differences were significant when resistance was measured in terms of damage caused by the herbivore, but not in terms of performance of the herbivore. Furthermore, we found the first evidence that the magnitude of resistance differences between introduced and native populations depended significantly on herbivore origin (i.e., whether the test herbivore was collected from the native or non-native range of the invasive plant). Finally, tolerance to generalists was found to be higher in introduced populations, while neither tolerance to specialists nor that to simulated herbivory differed between introduced and native plant populations. We conclude that enemy release from specialist herbivores and biotic resistance from generalist herbivores have contrasting effects on resistance evolution in invasive plants. Our results thus provide strong support for the Shifting Defense hypothesis. © 2018 by the Ecological Society of America.

  9. Impacts of invasive plants on carbon pools depend on both species' traits and local climate.

    Science.gov (United States)

    Martin, Philip A; Newton, Adrian C; Bullock, James M

    2017-04-01

    Invasive plants can alter ecosystem properties, leading to changes in the ecosystem services on which humans depend. However, generalizing about these effects is difficult because invasive plants represent a wide range of life forms, and invaded ecosystems differ in their plant communities and abiotic conditions. We hypothesize that differences in traits between the invader and native species can be used to predict impacts and so aid generalization. We further hypothesize that environmental conditions at invaded sites modify the effect of trait differences and so combine with traits to predict invasion impacts. To test these hypotheses, we used systematic review to compile data on changes in aboveground and soil carbon pools following non-native plant invasion from studies across the World. Maximum potential height (H max ) of each species was drawn from trait databases and other sources. We used meta-regression to assess which of invasive species' H max , differences in this height trait between native and invasive plants, and climatic water deficit, a measure of water stress, were good predictors of changes in carbon pools following invasion. We found that aboveground biomass in invaded ecosystems relative to uninvaded ones increased as the value of H max of invasive relative to native species increased, but that this effect was reduced in more water stressed ecosystems. Changes in soil carbon pools were also positively correlated with the relative H max of invasive species, but were not altered by water stress. This study is one of the first to show quantitatively that the impact of invasive species on an ecosystem may depend on differences in invasive and native species' traits, rather than solely the traits of invasive species. Our study is also the first to show that the influence of trait differences can be altered by climate. Further developing our understanding of the impacts of invasive species using this framework could help researchers to identify not

  10. Invaded Invaders: Infection of Invasive Brown Treesnakes on Guam by an Exotic Larval Cestode with a Life Cycle Comprised of Non-Native Hosts.

    Directory of Open Access Journals (Sweden)

    Elden T Holldorf

    Full Text Available Multiple host introductions to the same non-native environment have the potential to complete life cycles of parasites incidentally transported with them. Our goal was to identify a recently detected parasitic flatworm in the invasive Brown Treesnake (Boiga irregularis on the remote Pacific island of Guam. We considered possible factors influencing parasite transmission, and tested for correlations between infection status and potential indicators of host fitness. We used genetic data from the parasite and information about the native ranges of other possible non-native hosts to hypothesize how it arrived on Guam and how its life cycle may be currently supported.We identified the parasite by comparing larval morphology and mtDNA sequences with other Pseudophyllid tapeworms. We assessed probability of infection in individual snakes using logistic regression and examined different factors influencing presence of parasites in hosts.We identified the parasite as the pseudophyllid cestode Spirometra erinaceieuropaei, with all sampled worms from multiple snakes sharing a single mtDNA haplotype. Infection appears to be limited to the only freshwater watershed on the island, where infection prevalence was high (77.5%. Larger snakes had a higher probability of being infected, consistent with the chronic nature of such infections. While infection status was positively correlated with body condition, infected snakes tended to have lower intra-peritoneal fat body mass, potentially indicating a negative effect on energy stores.We discovered that B. irregularis inhabiting a small area of forested habitat in a freshwater watershed on Guam are often infected by a novel parasite of Asian origin. While further work is needed, this species of Spirometra, itself a non-native species, likely depends on a suite of recently introduced hosts from different parts of the world to complete the life cycle. This baseline study provides little evidence of any effects on host

  11. Interactions of fire and nonnative species across an elevation/plant community gradient in Hawaii volcanoes national park

    Science.gov (United States)

    Alison Ainsworth; J. Boone Kauffman

    2010-01-01

    Invasive species interacting with fires pose a relatively unknown, but potentially serious, threat to the tropical forests of Hawaii. Fires may create conditions that facilitate species invasions, but the degree to which this occurs in different tropical plant communities has not been quantified. We documented the survival and establishment of plant species for 2 yr...

  12. Non-native molluscan colonizers on deliberately placed shipwrecks in the Florida Keys, with description of a new species of potentially invasive worm-snail (Gastropoda: Vermetidae

    Directory of Open Access Journals (Sweden)

    Rüdiger Bieler

    2017-04-01

    Full Text Available Artificial reefs created by deliberately sinking ships off the coast of the Florida Keys island chain are providing new habitat for marine invertebrates. This newly developing fouling community includes the previously reported invasive orange tube coral Tubastraea coccinea and the non-native giant foam oyster Hyotissa hyotis. New SCUBA-based surveys involving five shipwrecks spanning the upper, middle, and lower Florida Keys, show T. coccinea now also established in the lower Keys and H. hyotis likewise extending to new sites. Two additional mollusks found on the artificial reefs, the amathinid gastropod Cyclothyca pacei and gryphaeid oyster Hyotissa mcgintyi, the latter also common in the natural reef areas, are discussed as potentially non-native. A new species of sessile, suspension-feeding, worm-snail, Thylacodes vandyensis Bieler, Rawlings & Collins n. sp. (Vermetidae, is described from the wreck of the USNS Vandenberg off Key West and discussed as potentially invasive. This new species is compared morphologically and by DNA barcode markers to other known members of the genus, and may be a recent arrival from the Pacific Ocean. Thylacodes vandyensis is polychromatic, with individuals varying in both overall head-foot coloration and mantle margin color pattern. Females brood stalked egg capsules attached to their shell within the confines of their mantle cavity, and give rise to crawl-away juveniles. Such direct-developing species have the demonstrated capacity for colonizing habitats isolated far from their native ranges and establishing rapidly growing founder populations. Vermetid gastropods are common components of the marine fouling community in warm temperate and tropical waters and, as such, have been tagged as potentially invasive or with a high potential to be invasive in the Pacific Ocean. As vermetids can influence coral growth/composition in the Pacific and have been reported serving as intermediate hosts for blood flukes of

  13. DNA barcoding of invasive plants in China: A resource for identifying invasive plants.

    Science.gov (United States)

    Xu, Song-Zhi; Li, Zhen-Yu; Jin, Xiao-Hua

    2018-01-01

    Invasive plants have aroused attention globally for causing ecological damage and having a negative impact on the economy and human health. However, it can be extremely challenging to rapidly and accurately identify invasive plants based on morphology because they are an assemblage of many different families and many plant materials lack sufficient diagnostic characteristics during border inspections. It is therefore urgent to evaluate candidate loci and build a reliable genetic library to prevent invasive plants from entering China. In this study, five common single markers (ITS, ITS2, matK, rbcL and trnH-psbA) were evaluated using 634 species (including 469 invasive plant species in China, 10 new records to China, 16 potentially invasive plant species around the world but not introduced into China yet and 139 plant species native to China) based on three different methods. Our results indicated that ITS2 displayed largest intra- and interspecific divergence (1.72% and 91.46%). Based on NJ tree method, ITS2, ITS, matK, rbcL and trnH-psbA provided 76.84%, 76.5%, 63.21%, 52.86% and 50.68% discrimination rates, respectively. The combination of ITS + matK performed best and provided 91.03% discriminatory power, followed by ITS2 + matK (85.78%). For identifying unknown individuals, ITS + matK had 100% correct identification rate based on our database, followed by ITS/ITS2 (both 93.33%) and ITS2 + matK (91.67%). Thus, we propose ITS/ITS2 + matK as the most suitable barcode for invasive plants in China. This study also demonstrated that DNA barcoding is an efficient tool for identifying invasive species. © 2017 John Wiley & Sons Ltd.

  14. No universal scale-dependent impacts of invasive species on native plant species richness.

    Science.gov (United States)

    Stohlgren, Thomas J; Rejmánek, Marcel

    2014-01-01

    A growing number of studies seeking generalizations about the impact of plant invasions compare heavily invaded sites to uninvaded sites. But does this approach warrant any generalizations? Using two large datasets from forests, grasslands and desert ecosystems across the conterminous United States, we show that (i) a continuum of invasion impacts exists in many biomes and (ii) many possible species-area relationships may emerge reflecting a wide range of patterns of co-occurrence of native and alien plant species. Our results contradict a smaller recent study by Powell et al. 2013 (Science 339, 316-318. (doi:10.1126/science.1226817)), who compared heavily invaded and uninvaded sites in three biomes and concluded that plant communities invaded by non-native plant species generally have lower local richness (intercepts of log species richness-log area regression lines) but steeper species accumulation with increasing area (slopes of the regression lines) than do uninvaded communities. We conclude that the impacts of plant invasions on plant species richness are not universal.

  15. Interactive influences of wildfire and nonnative species on plant community succession in Hawaii Volcanoes National Park.

    Science.gov (United States)

    Alison Ainsworth

    2007-01-01

    The role of fire as a natural disturbance, its interactions with nonnative species and effects of repeated fires in the Hawaiian Islands have received little investigation. We are unsure of the role fire played in shaping forest structure and composition as well as affecting evolutionary processes of the native biota. Yet, many species do have adaptations that...

  16. Native plant community response to alien plant invasion and removal

    Directory of Open Access Journals (Sweden)

    Jara ANDREU

    2011-01-01

    Full Text Available Given the potential ecological impacts of invasive species, removal of alien plants has become an important management challenge and a high priority for environmental managers. To consider that a removal effort has been successful requires both, the effective elimination of alien plants and the restoration of the native plant community back to its historical composition and function. We present a conceptual framework based on observational and experimental data that compares invaded, non-invaded and removal sites to quantify invaders’ impacts and native plant recover after their removal. We also conduct a meta-analysis to quantitatively evaluate the impacts of plant invaders and the consequences of their removal on the native plant community, across a variety of ecosystems around the world. Our results that invasion by alien plants is responsible for a local decline in native species richness and abundance. Our analysis also provides evidence that after removal, the native vegetation has the potential to recover to a pre-invasion target state. Our review reveal that observational and experimental approaches are rarely used in concert, and that reference sites are scarcely employed to assess native species recovery after removal. However, we believe that comparing invaded, non-invaded and removal sites offer the opportunity to obtain scientific information with relevance for management.

  17. Invasion strategies in clonal aquatic plants: are phenotypic differences caused by phenotypic plasticity or local adaptation?

    Science.gov (United States)

    Riis, Tenna; Lambertini, Carla; Olesen, Birgit; Clayton, John S.; Brix, Hans; Sorrell, Brian K.

    2010-01-01

    Background and Aims The successful spread of invasive plants in new environments is often linked to multiple introductions and a diverse gene pool that facilitates local adaptation to variable environmental conditions. For clonal plants, however, phenotypic plasticity may be equally important. Here the primary adaptive strategy in three non-native, clonally reproducing macrophytes (Egeria densa, Elodea canadensis and Lagarosiphon major) in New Zealand freshwaters were examined and an attempt was made to link observed differences in plant morphology to local variation in habitat conditions. Methods Field populations with a large phenotypic variety were sampled in a range of lakes and streams with different chemical and physical properties. The phenotypic plasticity of the species before and after cultivation was studied in a common garden growth experiment, and the genetic diversity of these same populations was also quantified. Key Results For all three species, greater variation in plant characteristics was found before they were grown in standardized conditions. Moreover, field populations displayed remarkably little genetic variation and there was little interaction between habitat conditions and plant morphological characteristics. Conclusions The results indicate that at the current stage of spread into New Zealand, the primary adaptive strategy of these three invasive macrophytes is phenotypic plasticity. However, while limited, the possibility that genetic diversity between populations may facilitate ecotypic differentiation in the future cannot be excluded. These results thus indicate that invasive clonal aquatic plants adapt to new introduced areas by phenotypic plasticity. Inorganic carbon, nitrogen and phosphorous were important in controlling plant size of E. canadensis and L. major, but no other relationships between plant characteristics and habitat conditions were apparent. This implies that within-species differences in plant size can be explained

  18. A meta-analysis of trait differences between invasive and non-invasive plant species

    OpenAIRE

    van Kleunen, Mark; Weber, Ewald; Fischer, Markus

    2010-01-01

    A major aim in ecology is identifying determinants of invasiveness. We performed a meta-analysis of 117 field or experimental-garden studies that measured pair-wise trait differences of a total of 125 invasive and 196 non-invasive plant species in the invasive range of the invasive species. We tested whether invasiveness is associated with performance-related traits (physiology, leaf-area allocation, shoot allocation, growth rate, size and fitness), and whether such associations depend on typ...

  19. Invasion by nonnative brook trout in Panther Creek, Idaho: Roles of local habitat quality, biotic resistance, and connectivity to source habitats

    Science.gov (United States)

    Benjamin, Joseph R.; Dunham, Jason B.; Dare, M.R.

    2007-01-01

    Theoretical models and empirical evidence suggest that the invasion of nonnative species in freshwaters is facilitated through the interaction of three factors: habitat quality, biotic resistance, and connectivity. We measured variables that represented each factor to determine which were associated with the occurrence of nonnative brook trout Salvelinus fontinalis in Panther Creek, a tributary to the Salmon River, Idaho. Habitat variables included measures of summer and winter temperature, instream cover, and channel size. The abundance of native rainbow trout Oncorhynchus mykiss within sampled sites was used as a measure of biotic resistance. We also considered the connectivity of sample sites to unconfined valley bottoms, which were considered habitats that may serve as sources for the spread of established populations of brook trout. We analyzed the occurrence of small (<150‐mm [fork length]) and large (≥150‐mm) brook trout separately, assuming that the former represents an established invasion while accounting for the higher potential mobility of the latter. The occurrence of small brook trout was strongly associated with the proximity of sites to large, unconstrained valley bottoms, providing evidence that such habitats may serve as sources for the spread of brook trout invasion. Within sites, winter degree‐days and maximum summer temperature were positively associated with the occurrence of small brook trout. The occurrence of large brook trout was not related to any of the variables considered, perhaps due to the difficulty of linking site‐specific habitat factors to larger and more mobile individuals. The abundance of rainbow trout was not conclusively associated with the occurrence of either small or large brook trout, providing little support for the role of biotic resistance. Overall, our results suggest that source connectivity and local habitat characteristics, but not biotic resistance, influence the establishment and spread of

  20. Invasive plants on disturbed Korean sand dunes

    Science.gov (United States)

    Kim, Kee Dae

    2005-01-01

    The sand dunes in coastal regions of South Korea are important ecosystems because of their small size, the rare species found in this habitat, and the beautiful landscapes they create. This study investigated the current vegetative status of sand dunes on three representative coasts of the Korean peninsula, and on the coasts of Cheju Island, and assessed the conditions caused by invasive plants. The relationships between the degree of invasion and 14 environmental variables were studied. Plots of sand dunes along line transects perpendicular to the coastal lines were established to estimate vegetative species coverage. TWINSPAN (Two-Way Indicator Species Analysis), CCA (Canonical Correspondence Analysis), and DCCA (Detrended Canonical Correspondence Analysis) were performed to classify communities on sand dunes and assess species composition variation. Carex kobomugi, Elymus mollis, and Vitex rotundifolia were found to be the dominant species plotted on the east, the west, and the peripheral coasts of Cheju Island, respectively. Vegetation on the south coast was totally extinct. The 19 communities, including representative C. kobomugi, C. kobomugi- Ixeris repens, C. kobomugi- Oenothera biennis, E. mollis, Lolium multiflorum- Calystegia soldanella, and V. rotundifolia- C. kobomugi, were all classified according to TWINSPAN. Oenothera biennis and L. multiflorum were exotics observed within these native communities. CCA showed that invasive native and exotic species distribution was segregated significantly, according to disturbance level, exotic species number, gravel, sand and silt contents, as well as vegetation size. It further revealed that human disturbance can strongly favor the settlement of invasive and exotic species. Restoration options to reduce exotic plants in the South Korean sand dune areas were found to be the introduction of native plant species from one sand dune into other sand dune areas, prohibition of building and the introduction of exotic

  1. Evolutionary responses of native plant species to invasive plants : a review

    OpenAIRE

    Oduor, Ayub M. O.

    2013-01-01

    Strong competition from invasive plant species often leads to declines in abundances and may,in certain cases, cause localized extinctions of native plant species. Nevertheless, studies have shown that certain populations of native plant species can co-exist with invasive plant species, suggesting the possibility of adaptive evolutionary responses of those populations to the invasive plants. Empirical inference of evolutionary responses of the native plant species to invasive plants has invol...

  2. Growth form and distribution of introduced plants in their native and non-native ranges in Eastern Asia and North America

    Science.gov (United States)

    Robert E. Ricklefs; Qinfeng Guo; Hong Qian

    2008-01-01

    There is a growing interest in understanding the influence of plant traits on their ability to spread in non-native regions. Many studies addressing this issue have been based on relatively small areas or restricted taxonomic groups. Here, we analyse a large data base involving 1567 plant species introduced between Eastern Asia and North America or from elsewhere to...

  3. Minimal effectiveness of native and non-native seeding following three high-severity wildfire

    Science.gov (United States)

    Ken A. Stella; Carolyn H. Sieg; Pete Z. Fule

    2010-01-01

    The rationale for seeding following high-severity wildfires is to enhance plant cover and reduce bare ground, thus decreasing the potential for soil erosion and non-native plant invasion. However, experimental tests of the effectiveness of seeding in meeting these objectives in forests are lacking. We conducted three experimental studies of the effectiveness of seeding...

  4. Invasion of a mined landscape: what habitat characteristics are influencing the occurrence of invasive plants?

    Science.gov (United States)

    D. Lemke; I.A. Tazisong; Y. Wang; J.A. Brown

    2012-01-01

    Throughout the world, the invasion of alien plants is an increasing threat to native biodiversity. Invasion is especially prevalent in areas affected by land transformation and anthropogenic disturbance. Surface mines are a major disturbance, and thus may promote the establishment and expansion of invasive plant communities. Environmental and habitat factors that may...

  5. Colorful invasion in permissive Neotropical ecosystems: establishment of ornamental non-native poeciliids of the genera Poecilia/Xiphophorus (Cyprinodontiformes: Poeciliidae and management alternatives

    Directory of Open Access Journals (Sweden)

    André Lincoln Barroso Magalhães

    2017-03-01

    Full Text Available ABSTRACT Headwater creeks are environments susceptible to invasion by non-native fishes. We evaluated the reproduction of 22 populations of the non-native livebearers guppy Poecilia reticulata, black molly Poecilia sphenops, Yucatan molly Poecilia velifera, green swordtail Xiphophorus hellerii, southern platyfish Xiphophorus maculatus, and variable platyfish Xiphophorus variatus during an annual cycle in five headwater creeks located in the largest South American ornamental aquaculture center, Paraíba do Sul River basin, southeastern Brazil. With few exceptions, females of most species were found reproducing (stages 2, 3, 4 all year round in the creeks and gravid females of all species showed small sizes indicating stunting. Juveniles were frequent in all sites. The fecundity of the six poeciliids was always low in all periods. The sex ratio was biased for females in most species, both bimonthly as for the whole period. Water temperature, water level and rainfall were not significantly correlated with reproduction in any species. Therefore, most populations appeared well established. The pertinence of different management actions, such as devices to prevent fish escape, eradication with rotenone and research about negative effects on native species, is discussed in the light of current aquaculture practices in the region.

  6. Vulnerability of freshwater native biodiversity to non-native ...

    Science.gov (United States)

    Background/Question/Methods Non-native species pose one of the greatest threats to native biodiversity. The literature provides plentiful empirical and anecdotal evidence of this phenomenon; however, such evidence is limited to local or regional scales. Employing geospatial analyses, we investigate the potential threat of non-native species to threatened and endangered aquatic animal taxa inhabiting unprotected areas across the continental US. We compiled distribution information from existing publicly available databases at the watershed scale (12-digit hydrologic unit code). We mapped non-native aquatic plant and animal species richness, and an index of cumulative invasion pressure, which weights non-native richness by the time since invasion of each species. These distributions were compared to the distributions of native aquatic taxa (fish, amphibians, mollusks, and decapods) from the International Union for the Conservation of Nature (IUCN) database. We mapped the proportion of species listed by IUCN as threatened and endangered, and a species rarity index per watershed. An overlay analysis identified watersheds experiencing high pressure from non-native species and also containing high proportions of threatened and endangered species or exhibiting high species rarity. Conservation priorities were identified by generating priority indices from these overlays and mapping them relative to the distribution of protected areas across the US. Results/Conclusion

  7. Salinity tolerance of non-native suckermouth armoured catfish (Loricariidae: Pterygoplichthys) in south-eastern Mexico: implications for invasion and dispersal

    Science.gov (United States)

    Capps, Krista A.; Nico, Leo G.; Mendoza-Carranza, Manuel; Arevalo-Frias, Wendi; Ropicki, Andrew J.; Heilpern, Sebastian A.; Rodiles-Hernandez, Rocio

    2011-01-01

    1. Salinity tolerance is one of several important physiological attributes that determine invasion success and the pattern of dispersal of introduced aquatic organisms. Introduced freshwater fishes able to tolerate elevated salinities have the potential to invade and exploit brackish-water (mixohaline) environments and use estuaries and coastal waters as 'bridges' for dispersing from one coastal river system to another. 2. Several members of the neotropical suckermouth armoured catfish genus Pterygoplichthys (Siluriformes: Loricariidae) have established non-native populations in inland waters of North and Central America, Asia and islands in the Caribbean, and Pacific and Indian oceans. Loricariids are generally considered to be strictly freshwater; but a few naturally occur in mesohaline habitats. 3.Catch and habitat data from 2004–2005 and 2009–2011 fish surveys in the Grijalva–Usumacinta River delta region (south-eastern Mexico) confirmed that introduced Pterygoplichthys populations established in upstream freshwater sites (where these catfish are abundant) have recently dispersed into downstream oligohaline and mesohaline estuarine habitats. During 2009–2011 surveys, these non-native catfish — tentatively identified as P. pardalis or its hybrids — were found in sites with salinities ranging from 1 to 8 ppt (mean 5.2 ppt). 4.Acute-salinity experiments were conducted with Pterygoplichthys (110–302 mm standard length, N=140) captured in the Grijalva–Usumacinta Basin to determine upper salinity tolerance levels. Tests demonstrated that individuals maintained in salinities of 0.2 ppt were able to survive abrupt (acute) exposure to salinities up to 10 ppt with little mortality over 10 days (240 h experimental endpoint). A few individuals survived abrupt exposure to 11 and 12 ppt for 20 or more hours, although none survived more than a few hours at 16 ppt or greater. 5.These field and experimental results provide quantitative evidence that non-native

  8. Invasive Plant Species in the National Parks of Vietnam

    OpenAIRE

    Bernard Dell; Pham Quang Thu; Dang Thanh Tan

    2012-01-01

    The impact of invasive plant species in national parks and forests in Vietnam is undocumented and management plans have yet to be developed. Ten national parks, ranging from uncut to degraded forests located throughout Vietnam, were surveyed for invasive plant species. Transects were set up along roads, trails where local people access park areas, and also tracks through natural forest. Of 134 exotic weeds, 25 were classified as invasive species and the number of invasive species ranged from ...

  9. Response of native insect communities to invasive plants.

    Science.gov (United States)

    Bezemer, T Martijn; Harvey, Jeffrey A; Cronin, James T

    2014-01-01

    Invasive plants can disrupt a range of trophic interactions in native communities. As a novel resource they can affect the performance of native insect herbivores and their natural enemies such as parasitoids and predators, and this can lead to host shifts of these herbivores and natural enemies. Through the release of volatile compounds, and by changing the chemical complexity of the habitat, invasive plants can also affect the behavior of native insects such as herbivores, parasitoids, and pollinators. Studies that compare insects on related native and invasive plants in invaded habitats show that the abundance of insect herbivores is often lower on invasive plants, but that damage levels are similar. The impact of invasive plants on the population dynamics of resident insect species has been rarely examined, but invasive plants can influence the spatial and temporal dynamics of native insect (meta)populations and communities, ultimately leading to changes at the landscape level.

  10. Defining a regional approach for invasive plant research and management.

    Science.gov (United States)

    Steven R. Radosevich; Bryan A. Endress; Catherine G. Parks

    2005-01-01

    Invasive plants are now recognized as a serious threat to most extensive management systems, such as forests, meadows, deserts, and riparian areas [1-3]. Vitousek et al. [3] described exotic plant invasion as a significant element of global environmental change because exotic plants can alter primary productivity, decomposition, hydrology, nutrient cycling, and natural...

  11. INVASIVE ALIEN PLANT SPECIES USED FOR THE TREATMENT OF VARIOUS DISEASES IN LIMPOPO PROVINCE, SOUTH AFRICA.

    Science.gov (United States)

    Maema, Lesibana Peter; Potgieter, Martin; Mahlo, Salome Mamokone

    2016-01-01

    Invasive alien plant species (IAPs) are plants that have migrated from one geographical region to non-native region either intentional or unintentional. The general view of IAPs in environment is regarded as destructive to the ecosystem and they pose threat to native vegetation and species. However, some of these IAPS are utilized by local inhabitants as a substitute for scarce indigenous plants. The aim of the study is to conduct ethnobotanical survey on medicinal usage of invasive plant species in Waterberg District, Limpopo Province, South Africa. An ethnobotanical survey on invasive plant species was conducted to distinguish species used for the treatment of various ailments in the Waterberg, District in the area dominated by Bapedi traditional healers. About thirty Bapedi traditional healers (30) were randomly selected via the snowball method. A guided field work by traditional healers and a semi-structured questionnaire was used to gather information from the traditional healers. The questionnaire was designed to gather information on the local name of plants, plant parts used and methods of preparation which is administered by the traditional healers. The study revealed that Schinus molle L., Catharanthus roseus (L.), Datura stramonium L., Opuntia stricta (Haw.) Haw., Opuntia ficus- indica, Sambucus canadensis L., Ricinus communis L., Melia azedarch L., Argemone ochroleuca and Eriobotrya japónica are used for treatment of various diseases such as chest complaint, blood purification, asthma, hypertension and infertility. The most plant parts that were used are 57.6% leaves, followed by 33.3% roots, and whole plant, seeds and bark at 3% each. Noticeably, most of these plants are cultivated (38%), followed by 28% that are common to the study area, 20% abundant, 12% wild, and 3% occasionally. Schinus molle is the most frequently used plant species for the treatment of various ailments in the study area. National Environmental Management Biodiversity Act (NEMBA

  12. New pasture plants intensify invasive species risk.

    Science.gov (United States)

    Driscoll, Don A; Catford, Jane A; Barney, Jacob N; Hulme, Philip E; Inderjit; Martin, Tara G; Pauchard, Aníbal; Pyšek, Petr; Richardson, David M; Riley, Sophie; Visser, Vernon

    2014-11-18

    Agricultural intensification is critical to meet global food demand, but intensification threatens native species and degrades ecosystems. Sustainable intensification (SI) is heralded as a new approach for enabling growth in agriculture while minimizing environmental impacts. However, the SI literature has overlooked a major environmental risk. Using data from eight countries on six continents, we show that few governments regulate conventionally bred pasture taxa to limit threats to natural areas, even though most agribusinesses promote taxa with substantial weed risk. New pasture taxa (including species, subspecies, varieties, cultivars, and plant-endophyte combinations) are bred with characteristics typical of invasive species and environmental weeds. By introducing novel genetic and endophyte variation, pasture taxa are imbued with additional capacity for invasion and environmental impact. New strategies to prevent future problems are urgently needed. We highlight opportunities for researchers, agribusiness, and consumers to reduce environmental risks associated with new pasture taxa. We also emphasize four main approaches that governments could consider as they build new policies to limit weed risks, including (i) national lists of taxa that are prohibited based on environmental risk; (ii) a weed risk assessment for all new taxa; (iii) a program to rapidly detect and control new taxa that invade natural areas; and (iv) the polluter-pays principle, so that if a taxon becomes an environmental weed, industry pays for its management. There is mounting pressure to increase livestock production. With foresight and planning, growth in agriculture can be achieved sustainably provided that the scope of SI expands to encompass environmental weed risks.

  13. Negative impacts of invasive plants on conservation of sensitive desert wildlife

    Science.gov (United States)

    Drake, K. Kristina; Bowen, Lizabeth; Nussear, Kenneth E.; Esque, Todd C.; Berger, Andrew J.; Custer, Nathan; Waters, Shannon C.; Johnson, Jay D.; Miles, A. Keith; Lewison, Rebecca L.

    2016-01-01

    Habitat disturbance from development, resource extraction, off-road vehicle use, and energy development ranks highly among threats to desert systems worldwide. In the Mojave Desert, United States, these disturbances have promoted the establishment of nonnative plants, so that native grasses and forbs are now intermixed with, or have been replaced by invasive, nonnative Mediterranean grasses. This shift in plant composition has altered food availability for Mojave Desert tortoises (Gopherus agassizii), a federally listed species. We hypothesized that this change in forage would negatively influence the physiological ecology, immune competence, and health of neonatal and yearling tortoises. To test this, we monitored the effects of diet on growth, body condition, immunological responses (measured by gene transcription), and survival for 100 captive Mojave tortoises. Tortoises were assigned to one of five diets: native forbs, native grass, invasive grass, and native forbs combined with either the native or invasive grass. Tortoises eating native forbs had better body condition and immune functions, grew more, and had higher survival rates (>95%) than tortoises consuming any other diet. At the end of the experiment, 32% of individuals fed only native grass and 37% fed only invasive grass were found dead or removed from the experiment due to poor body conditions. In contrast, all tortoises fed either the native forb or combined native forb and native grass diets survived and were in good condition. Health and body condition quickly declined for tortoises fed only the native grass (Festuca octoflora) or invasive grass (Bromus rubens) with notable loss of fat and muscle mass and increased muscular atrophy. Bromus rubens seeds were found embedded in the oral mucosa and tongue in most individuals eating that diet, which led to mucosal inflammation. Genes indicative of physiological, immune, and metabolic functions were transcribed at lower levels for individuals fed B

  14. Impacts of invasive alien plants on water quality, with particular ...

    African Journals Online (AJOL)

    Impacts of invasive alien plants on water quality, with particular emphasis on South ... their spread results in native species loss, increased biomass and fire intensity ... areas by changing the size, distribution and plant chemistry of the biomass.

  15. Invasion of a dominant floral resource: effects on the floral community and pollination of native plants.

    Science.gov (United States)

    Goodell, Karen; Parker, Ingrid M

    2017-01-01

    Through competition for pollinators, invasive plants may suppress native flora. Community-level studies provide an integrative assessment of invasion impacts and insights into factors that influence the vulnerability of different native species. We investigated effects of the nonnative herb Lythrum salicaria on pollination of native species in 14 fens of the eastern United States. We compared visitors per flower for 122 native plant species in invaded and uninvaded fens and incorporated a landscape-scale experiment, removing L. salicaria flowers from three of the invaded fens. Total flower densities were more than three times higher in invaded than uninvaded or removal sites when L. salicaria was blooming. Despite an increase in number of visitors with number of flowers per area, visitors per native flower declined with increasing numbers of flowers. Therefore, L. salicaria invasion depressed visitation to native flowers. In removal sites, visitation to native flowers was similar to uninvaded sites, confirming the observational results and also suggesting that invasion had not generated a persistent build-up of visitor populations. To study species-level impacts, we examined effects of invasion on visitors per flower for the 36 plant species flowering in both invaded and uninvaded fens. On average, the effect of invasion represented about a 20% reduction in visits per flower. We measured the influence of plant traits on vulnerability to L. salicaria invasion using meta-analysis. Bilaterally symmetrical flowers experienced stronger impacts on visitation, and similarity in flower color to L. salicaria weakly intensified competition with the invader for visitors. Finally, we assessed the reproductive consequences of competition with the invader in a dominant flowering shrub, Dasiphora fruticosa. Despite the negative effect of invasion on pollinator visitation in this species, pollen limitation of seed production was not stronger in invaded than in uninvaded

  16. Invasive clonal plant species have a greater root-foraging plasticity than non-invasive ones.

    Science.gov (United States)

    Keser, Lidewij H; Dawson, Wayne; Song, Yao-Bin; Yu, Fei-Hai; Fischer, Markus; Dong, Ming; van Kleunen, Mark

    2014-03-01

    Clonality is frequently positively correlated with plant invasiveness, but which aspects of clonality make some clonal species more invasive than others is not known. Due to their spreading growth form, clonal plants are likely to experience spatial heterogeneity in nutrient availability. Plasticity in allocation of biomass to clonal growth organs and roots may allow these plants to forage for high-nutrient patches. We investigated whether this foraging response is stronger in species that have become invasive than in species that have not. We used six confamilial pairs of native European clonal plant species differing in invasion success in the USA. We grew all species in large pots under homogeneous or heterogeneous nutrient conditions in a greenhouse, and compared their nutrient-foraging response and performance. Neither invasive nor non-invasive species showed significant foraging responses to heterogeneity in clonal growth organ biomass or in aboveground biomass of clonal offspring. Invasive species had, however, a greater positive foraging response in terms of root and belowground biomass than non-invasive species. Invasive species also produced more total biomass. Our results suggest that the ability for strong root foraging is among the characteristics promoting invasiveness in clonal plants.

  17. Non-native species in the vascular flora of highlands and mountains of Iceland

    Directory of Open Access Journals (Sweden)

    Pawel Wasowicz

    2016-01-01

    Full Text Available The highlands and mountains of Iceland are one of the largest remaining wilderness areas in Europe. This study aimed to provide comprehensive and up-to-date data on non-native plant species in these areas and to answer the following questions: (1 How many non-native vascular plant species inhabit highland and mountainous environments in Iceland? (2 Do temporal trends in the immigration of alien species to Iceland differ between highland and lowland areas? (3 Does the incidence of alien species in the disturbed and undisturbed areas within Icelandic highlands differ? (4 Does the spread of non-native species in Iceland proceed from lowlands to highlands? and (5 Can we detect hot-spots in the distribution of non-native taxa within the highlands? Overall, 16 non-native vascular plant species were detected, including 11 casuals and 5 naturalized taxa (1 invasive. Results showed that temporal trends in alien species immigration to highland and lowland areas are similar, but it is clear that the process of colonization of highland areas is still in its initial phase. Non-native plants tended to occur close to man-made infrastructure and buildings including huts, shelters, roads etc. Analysis of spatio-temporal patterns showed that the spread within highland areas is a second step in non-native plant colonization in Iceland. Several statically significant hot spots of alien plant occurrences were identified using the Getis-Ord Gi* statistic and these were linked to human disturbance. This research suggests that human-mediated dispersal is the main driving force increasing the risk of invasion in Iceland’s highlands and mountain areas.

  18. UV Screening in Native and Non-native Plant Species in the Tropical Alpine: Implications for Climate Change-Driven Migration of Species to Higher Elevations

    Directory of Open Access Journals (Sweden)

    Paul W. Barnes

    2017-08-01

    Full Text Available Ongoing changes in Earth’s climate are shifting the elevation ranges of many plant species with non-native species often experiencing greater expansion into higher elevations than native species. These climate change-induced shifts in distributions inevitably expose plants to novel biotic and abiotic environments, including altered solar ultraviolet (UV-B (280–315 nm radiation regimes. Do the greater migration potentials of non-native species into higher elevations imply that they have more effective UV-protective mechanisms than native species? In this study, we surveyed leaf epidermal UV-A transmittance (TUV A in a diversity of plant species representing different growth forms to test whether native and non-native species growing above 2800 m elevation on Mauna Kea, Hawaii differed in their UV screening capabilities. We further compared the degree to which TUV A varied along an elevation gradient in the native shrub Vaccinium reticulatum and the introduced forb Verbascum thapsus to evaluate whether these species differed in their abilities to adjust their levels of UV screening in response to elevation changes in UV-B. For plants growing in the Mauna Kea alpine/upper subalpine, we found that adaxial TUV A, measured with a UVA-PAM fluorometer, varied significantly among species but did not differ between native (mean = 6.0%; n = 8 and non-native (mean = 5.8%; n = 11 species. When data were pooled across native and non-native taxa, we also found no significant effect of growth form on TUV A, though woody plants (shrubs and trees were represented solely by native species whereas herbaceous growth forms (grasses and forbs were dominated by non-native species. Along an elevation gradient spanning 2600–3800 m, TUV A was variable (mean range = 6.0–11.2% and strongly correlated with elevation and relative biologically effective UV-B in the exotic V. thapsus; however, TUV A was consistently low (3% and did not vary with elevation in the native

  19. Biological invasions: economic and environmental costs of alien plant, animal, and microbe species

    National Research Council Canada - National Science Library

    Pimentel, David

    2011-01-01

    ...: Economic and Environmental Costs of Alien Plant, Animal, and Microbe Species, this reference discusses how non-native species invade new ecosystems and the subsequent economic and environmental effects of these species...

  20. Private forest owners and invasive plants: risk perception and management

    Science.gov (United States)

    A. Paige Fischer; Susan Charnley

    2012-01-01

    We investigated nonindustrial private forest (NIPF) owners' invasive plant risk perceptions and mitigation practices using statistical analysis of mail survey data and qualitative analysis of interview data collected in Oregon's ponderosa pine zone. We found that 52% of the survey sample was aware of invasive plant species considered problematic by local...

  1. Synergy Between Pathogen Release and Resource Availability in Plant Invasion

    Science.gov (United States)

    Why do some exotic plant species become invasive? Two common hypotheses, increased resource availability and enemy release, may more effectively explain invasion if they favor the same species, and therefore act in concert. This would be expected if plant species adapted to high levels of available ...

  2. Invasive plant erodes local song diversity in a migratory passerine

    Science.gov (United States)

    Yvette K. Ortega; Aubree Benson; Erick Greene

    2014-01-01

    Exotic plant invasions threaten ecosystems globally, but we still know little about the specific consequences for animals. Invasive plants can alter the quality of breeding habitat for songbirds, thereby impacting important demographic traits such as dispersal, philopatry, and age structure. These demographic effects may in turn alter song-learning conditions to affect...

  3. Invasion Success by Plant Breeding Evolutionary Changes as a Critical Factor for the Invasion of the Ornamental Plant Mahonia aquifolium

    CERN Document Server

    Ross, Christel Anne

    2009-01-01

    Invasive species are a major threat to global biodiversity and cause significant economic costs. Studying biological invasions is both essential for preventing future invasions and is also useful in order to understand basic ecological processes. Christel Ross investigates whether evolutionary changes by plant breeding are a relevant factor for the invasion success of Mahonia aquifolium in Germany. Her findings show that invasive populations differ from native populations in quantitative-genetic traits and molecular markers, whereas their genetic diversity is similar. She postulates that these evolutionary changes are rather a result of plant breeding, which includes interspecific hybridisation, than the result of a genetic bottleneck or the releases from specialist herbivores.

  4. Of Asian forests and European fields: Eastern U.S. plant invasions in a global floristic context.

    Directory of Open Access Journals (Sweden)

    Jason D Fridley

    Full Text Available BACKGROUND: Biogeographic patterns of species invasions hold important clues to solving the recalcitrant 'who', 'where', and 'why' questions of invasion biology, but the few existing studies make no attempt to distinguish alien floras (all non-native occurrences from invasive floras (rapidly spreading species of significant management concern, nor have invasion biologists asked whether particular habitats are consistently invaded by species from particular regions. METHODOLOGY/PRINCIPAL FINDINGS: Here I describe the native floristic provenances of the 2629 alien plant taxa of the Eastern Deciduous Forest of the Eastern U.S. (EUS, and contrast these to the subset of 449 taxa that EUS management agencies have labeled 'invasive'. Although EUS alien plants come from all global floristic regions, nearly half (45% have native ranges that include central and northern Europe or the Mediterranean (39%. In contrast, EUS invasive species are most likely to come from East Asia (29%, a pattern that is magnified when the invasive pool is restricted to species that are native to a single floristic region (25% from East Asia, compared to only 11% from northern/central Europe and 2% from the Mediterranean. Moreover, East Asian invaders are mostly woody (56%, compared to just 23% of the total alien flora and are significantly more likely to invade intact forests and riparian areas than European species, which dominate managed or disturbed ecosystems. CONCLUSIONS/SIGNIFICANCE: These patterns suggest that the often-invoked 'imperialist dogma' view of global invasions equating invasion events with the spread of European colonialism is at best a restricted framework for invasion in disturbed ecosystems. This view must be superseded by a biogeographic invasion theory that is explicitly habitat-specific and can explain why particular world biotas tend to dominate particular environments.

  5. Effectiveness of FISK, an invasiveness screening tool for non-native freshwater fishes, to perform risk identification assessments in the Iberian Peninsula.

    Science.gov (United States)

    Almeida, David; Ribeiro, Filipe; Leunda, Pedro M; Vilizzi, Lorenzo; Copp, Gordon H

    2013-08-01

    Risk assessments are crucial for identifying and mitigating impacts from biological invasions. The Fish Invasiveness Scoring Kit (FISK) is a risk identification (screening) tool for freshwater fishes consisting of two subject areas: biogeography/history and biology/ecology. According to the outcomes, species can be classified under particular risk categories. The aim of this study was to apply FISK to the Iberian Peninsula, a Mediterranean climate region highly important for freshwater fish conservation due to a high level of endemism. In total, 89 fish species were assessed by three independent assessors. Results from receiver operating characteristic analysis showed that FISK can discriminate reliably between noninvasive and invasive fishes for Iberia, with a threshold of 20.25, similar to those obtained in several regions around the world. Based on mean scores, no species was categorized as "low risk," 50 species as "medium risk," 17 as "moderately high risk," 11 as "high risk," and 11 as "very high risk." The highest scoring species was goldfish Carassius auratus. Mean certainty in response was above the category "mostly certain," ranging from tinfoil barb Barbonymus schwanenfeldii with the lowest certainty to eastern mosquitofish Gambusia holbrooki with the highest level. Pair-wise comparison showed significant differences between one assessor and the other two on mean certainty, with these two assessors showing a high coincidence rate for the species categorization. Overall, the results suggest that FISK is a useful and viable tool for assessing risks posed by non-native fish in the Iberian Peninsula and contributes to a "watch list" in this region. © 2013 Crown copyright This article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.

  6. Herbarium specimens show patterns of fruiting phenology in native and invasive plant species across New England.

    Science.gov (United States)

    Gallinat, Amanda S; Russo, Luca; Melaas, Eli K; Willis, Charles G; Primack, Richard B

    2018-01-01

    Patterns of fruiting phenology in temperate ecosystems are poorly understood, despite the ecological importance of fruiting for animal nutrition and seed dispersal. Herbarium specimens represent an under-utilized resource for investigating geographical and climatic factors affecting fruiting times within species, patterns in fruiting times among species, and differences between native and non-native invasive species. We examined over 15,000 herbarium specimens, collected and housed across New England, and found 3159 specimens with ripe fruits, collected from 1849-2013. We examined patterns in fruiting phenology among 37 native and 18 invasive woody plant species common to New England. We compared fruiting dates between native and invasive species, and analyzed how fruiting phenology varies with temperature, space, and time. Spring temperature and year explained a small but significant amount of the variation in fruiting dates. Accounting for the moderate phylogenetic signal in fruiting phenology, invasive species fruited 26 days later on average than native species, with significantly greater standard deviations. Herbarium specimens can be used to detect patterns in fruiting times among species. However, the amount of intraspecific variation in fruiting times explained by temporal, geographic, and climatic predictors is small, due to a combination of low temporal resolution of fruiting specimens and the protracted nature of fruiting. Later fruiting times in invasive species, combined with delays in autumn bird migrations in New England, may increase the likelihood that migratory birds will consume and disperse invasive seeds in New England later into the year. © 2018 Botanical Society of America.

  7. Impact scores of invasive plants are biased by disregard of environmental co-variation and non-linearity

    Directory of Open Access Journals (Sweden)

    Jan Thiele

    2011-10-01

    Full Text Available Prioritisation of high-impact species is becoming increasingly important for management of introduced species (‘neobiota’ because of their growing number of which, however, only a small fraction has substantial impacts. Impact scores for prioritising species may be affected by the type of effect model used. Recent studies have shown that environmental co-variation and non-linearity may be significant for effect models of biological invasions. Here, we test for differences in impact scores between simple and complex effect models of three invasive plant species (Heracleum mantegazzianum, Lupinus polyphyllus, Rosa rugosa.We investigated the effects of cover percentages of the invasive plants on species richness of invaded communities using both simple linear effect models (‘basic models’ and more complex linear or non-linear models including environmental co-factors (‘full models’. Then, we calculated impact scores for each invasive species as the average reduction of species richness predicted by basic and full effect models.All three non-native species had negative effects on species richness, but the full effect models also indicated significant influence of habitat types. Heracleum mantegazzianum had uniform linear effects in all habitats, while effects of L. polyphyllus interacted strongly with habitat type, and R. rugosa showed a marked non-linear relationship. Impact scores were overestimated by basic effect models for H. mantegazzianum and R. rugosa due to disregard of habitat effects and non-linearity, respectively. In contrast, impact of L. polyphyllus was underestimated by the basic model that did not account for the strong interaction of invader cover and habitat type.We conclude that simple linear models will often yield inaccurate impact scores of non-native species. Hence, effect models should consider environmental co-variation and, if necessary, non-linearity of the effects of biological invasions on native ecosystems.

  8. Assessing plant community composition fails to capture impacts of white-tailed deer on native and invasive plant species.

    Science.gov (United States)

    Nuzzo, Victoria; Dávalos, Andrea; Blossey, Bernd

    2017-07-01

    Excessive herbivory can have transformative effects on forest understory vegetation, converting diverse communities into depauperate ones, often with increased abundance of non-native plants. White-tailed deer are a problematic herbivore throughout much of eastern North America and alter forest understory community structure. Reducing (by culling) or eliminating (by fencing) deer herbivory is expected to return understory vegetation to a previously diverse condition. We examined this assumption from 1992 to 2006 at Fermilab (Batavia, IL) where a cull reduced white-tailed deer ( Odocoileus virginianus ) abundance in 1998/1999 by 90 % from 24.6 to 2.5/km 2 , and at West Point, NY, where we assessed interactive effects of deer, earthworms, and invasive plants using 30 × 30 m paired fenced and open plots in 12 different forests from 2009 to 2012. We recorded not only plant community responses (species presence and cover) within 1 m 2 quadrats, but also responses of select individual species (growth, reproduction). At Fermilab, introduced Alliaria petiolata abundance initially increased as deer density increased, but then declined after deer reduction. The understory community responded to the deer cull by increased cover, species richness and height, and community composition changed but was dominated by early successional native forbs. At West Point plant community composition was affected by introduced earthworm density but not deer exclusion. Native plant cover increased and non-native plant cover decreased in fenced plots, thus keeping overall plant cover similar. At both sites native forb cover increased in response to deer reduction, but the anticipated response of understory vegetation failed to materialize at the community level. Deer-favoured forbs ( Eurybia divaricata , Maianthemum racemosum , Polygonatum pubescens and Trillium recurvatum ) grew taller and flowering probability increased in the absence of deer. Plant community monitoring fails to capture

  9. Resource competition in plant invasions: emerging patterns and research needs.

    Science.gov (United States)

    Gioria, Margherita; Osborne, Bruce A

    2014-01-01

    Invasions by alien plants provide a unique opportunity to examine competitive interactions among plants. While resource competition has long been regarded as a major mechanism responsible for successful invasions, given a well-known capacity for many invaders to become dominant and reduce plant diversity in the invaded communities, few studies have measured resource competition directly or have assessed its importance relative to that of other mechanisms, at different stages of an invasion process. Here, we review evidence comparing the competitive ability of invasive species vs. that of co-occurring native plants, along a range of environmental gradients, showing that many invasive species have a superior competitive ability over native species, although invasive congeners are not necessarily competitively superior over native congeners, nor are alien dominants are better competitors than native dominants. We discuss how the outcomes of competition depend on a number of factors, such as the heterogeneous distribution of resources, the stage of the invasion process, as well as phenotypic plasticity and evolutionary adaptation, which may result in increased or decreased competitive ability in both invasive and native species. Competitive advantages of invasive species over natives are often transient and only important at the early stages of an invasion process. It remains unclear how important resource competition is relative to other mechanisms (competition avoidance via phenological differences, niche differentiation in space associated with phylogenetic distance, recruitment and dispersal limitation, indirect competition, and allelopathy). Finally, we identify the conceptual and methodological issues characterizing competition studies in plant invasions, and we discuss future research needs, including examination of resource competition dynamics and the impact of global environmental change on competitive interactions between invasive and native species.

  10. Resource competition in plant invasions: emerging patterns and research needs

    Science.gov (United States)

    Gioria, Margherita; Osborne, Bruce A.

    2014-01-01

    Invasions by alien plants provide a unique opportunity to examine competitive interactions among plants. While resource competition has long been regarded as a major mechanism responsible for successful invasions, given a well-known capacity for many invaders to become dominant and reduce plant diversity in the invaded communities, few studies have measured resource competition directly or have assessed its importance relative to that of other mechanisms, at different stages of an invasion process. Here, we review evidence comparing the competitive ability of invasive species vs. that of co-occurring native plants, along a range of environmental gradients, showing that many invasive species have a superior competitive ability over native species, although invasive congeners are not necessarily competitively superior over native congeners, nor are alien dominants are better competitors than native dominants. We discuss how the outcomes of competition depend on a number of factors, such as the heterogeneous distribution of resources, the stage of the invasion process, as well as phenotypic plasticity and evolutionary adaptation, which may result in increased or decreased competitive ability in both invasive and native species. Competitive advantages of invasive species over natives are often transient and only important at the early stages of an invasion process. It remains unclear how important resource competition is relative to other mechanisms (competition avoidance via phenological differences, niche differentiation in space associated with phylogenetic distance, recruitment and dispersal limitation, indirect competition, and allelopathy). Finally, we identify the conceptual and methodological issues characterizing competition studies in plant invasions, and we discuss future research needs, including examination of resource competition dynamics and the impact of global environmental change on competitive interactions between invasive and native species. PMID

  11. 78 FR 75313 - Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To Reclassify...

    Science.gov (United States)

    2013-12-11

    ... the removal or reduction of the Act's protections. A species is an ``endangered species'' for purposes... invasive, nonnative plant species was not identified as a specific threat to E. altissimum in the 1994... and its habitat. The primary invasive, nonnative species of concern is Ehrharta calycina, a perennial...

  12. Host heterogeneity influences the impact of a non-native disease invasion on populations of a foundation tree species

    Science.gov (United States)

    Jules, Erik S.; Carroll, Allyson L.; Garcia, Andrea M.; Steenbock, Christopher M.; Kauffman, Matthew J.

    2014-01-01

    Invasive pathogens are becoming increasingly important in forested ecosystems, yet they are often difficult to study because of their rapid transmission. The rate and extent of pathogen spread are thought to be partially controlled by variation in host characteristics, such as when host size and location influence susceptibility. Few host-pathogen systems, however, have been used to test this prediction. We used Port Orford cedar (Chamaecyparis lawsoniana), a foundation tree species in riparian areas of California and Oregon (USA), and the invasive oomycete Phytophthora lateralis to assess pathogen impacts and the role of host characteristics on invasion. Across three streams that had been infected for 13–18 years by P. lateralis, we mapped 2241 trees and determined whether they had been infected using dendrochronology. The infection probability of trees was governed by host size (diameter at breast height [DBH]) and geomorphic position (e.g., active channel, stream bank, floodplain, etc.) similarly across streams. For instance, only 23% of trees <20 cm DBH were infected, while 69% of trees ≥20 cm DBH were infected. Presumably, because spores of P. lateralis are transported downstream in water, they are more likely to encounter well-developed root systems of larger trees. Also because of this water-transport of spores, differences in infection probability were found across the geomorphic positions: 59% of cedar in the active channel and the stream bank (combined) were infected, while 23% of trees found on higher geomorphic types were infected. Overall, 32% of cedar had been infected across the three streams. However, 63% of the total cedar basal area had been killed, because the greatest number of trees, and the largest trees, were found in the most susceptible positions. In the active channel and stream bank, 91% of the basal area was infected, while 46% was infected across higher geomorphic positions. The invasion of Port Orford cedar populations by

  13. Modelling Hotspots for Invasive Alien Plants in India.

    Science.gov (United States)

    Adhikari, Dibyendu; Tiwary, Raghuvar; Barik, Saroj Kanta

    2015-01-01

    Identification of invasion hotspots that support multiple invasive alien species (IAS) is a pre-requisite for control and management of invasion. However, till recently it remained a methodological challenge to precisely determine such invasive hotspots. We identified the hotspots of alien species invasion in India through Ecological Niche Modelling (ENM) using species occurrence data from the Global Biodiversity Information Facility (GBIF). The predicted area of invasion for selected species were classified into 4 categories based on number of model agreements for a region i.e. high, medium, low and very low. About 49% of the total geographical area of India was predicted to be prone to invasion at moderate to high levels of climatic suitability. The intersection of anthropogenic biomes and ecoregions with the regions of 'high' climatic suitability was classified as hotspot of alien plant invasion. Nineteen of 47 ecoregions of India, harboured such hotspots. Most ecologically sensitive regions of India, including the 'biodiversity hotspots' and coastal regions coincide with invasion hotspots, indicating their vulnerability to alien plant invasion. Besides demonstrating the usefulness of ENM and open source data for IAS management, the present study provides a knowledge base for guiding the formulation of an effective policy and management strategy for controlling the invasive alien species.

  14. Hybridization between invasive populations of Dalmatian toadflax (Linaria dalmatica) and yellow toadflax (Linaria vulgaris)

    Science.gov (United States)

    Sarah M. Ward; Caren E. Fleischmann; Marie F. Turner; Sharlene E. Sing

    2009-01-01

    Although there is evidence that interspecific hybridization can initiate invasion by nonnative plants, there are few documented examples of novel hybridization events between introduced plant species already exhibiting invasive behavior. We conducted morphometric and molecular analyses of toadflax plants with intermediate morphology found at two sites in Montana, which...

  15. Integrating invasive species policies across ornamental horticulture supply chains to prevent plant invasions

    NARCIS (Netherlands)

    Hulme, Philip E.; Brundu, Giuseppe; Carboni, Marta; Dehnen-schmutz, Katharina; Dullinger, Stefan; Early, Regan; Essl, Franz; González-moreno, Pablo; Groom, Quentin J.; Kueffer, Christoph; Kühn, Ingolf; Maurel, Noëlie; Novoa, Ana; Pergl, Jan; Pyšek, Petr; Seebens, Hanno; Tanner, Rob; Touza, Julia M.; Van Kleunen, Mark; Verbrugge, Laura Nicoline Halley

    2017-01-01

    1.Ornamental horticulture is the primary pathway for invasive alien plant introductions. We critically appraise published evidence on the effectiveness of four policy instruments that tackle invasions along the horticulture supply chain: pre-border import restrictions, post-border bans, industry

  16. Efficient distinction of invasive aquatic plant species from non-invasive related species using DNA barcoding

    NARCIS (Netherlands)

    Ghahramanzadeh, R.; Esselink, G.; Kodde, L.P.; Duistermaat, H.; Valkenburg, van J.L.C.H.; Marashi, S.H.; Smulders, M.J.M.; Wiel, van de C.C.M.

    2013-01-01

    Biological invasions are regarded as threats to global biodiversity. Among invasive aliens, a number of plant species belonging to the genera Myriophyllum, Ludwigia and Cabomba, and to the Hydrocharitaceae family pose a particular ecological threat to water bodies. Therefore, one would try to

  17. Evolutionary responses of native plant species to invasive plants: a review.

    Science.gov (United States)

    Oduor, Ayub M O

    2013-12-01

    Strong competition from invasive plant species often leads to declines in abundances and may, in certain cases, cause localized extinctions of native plant species. Nevertheless, studies have shown that certain populations of native plant species can co-exist with invasive plant species,suggesting the possibility of adaptive evolutionary responses of those populations to the invasive plants. Empirical inference of evolutionary responses of the native plant species to invasive plants has involved experiments comparing two conspecific groups of native plants for differences in expression of growth/reproductive traits: populations that have experienced competition from the invasive plant species (i.e. experienced natives) versus populations with no known history of interactions with the invasive plant species (i.e. naıve natives). Here, I employ a meta-analysis to obtain a general pattern of inferred evolutionary responses of native plant species from 53 such studies. In general, the experienced natives had significantly higher growth/reproductive performances than naıve natives, when grown with or without competition from invasive plants.While the current results indicate that certain populations of native plant species could potentially adapt evolutionarily to invasive plant species, the ecological and evolutionary mechanisms that probably underlie such evolutionary responses remain unexplored and should be the focus of future studies.

  18. Inventory of the Invasive Alien Plant Species in Indonesia

    OpenAIRE

    TJITROSOEDIRDJO, SRI SUDARMIYATI

    2005-01-01

    An inventory of the alien plant species in Indonesia based on the existing references and herbarium specimens concluded that 1936 alien plant species are found in Indonesia which belong to 187 families. Field studies should be done to get the complete figures of alien plant species in Indonesia. Based on the existing figures of the plant species, the invasive alien plant species can be identified, followed by studies on the assessment of losses, biology, management and their possible utilizat...

  19. Biotic constraints on the establishment and performance of native, naturalized, and invasive plants in Pacific Northwest (USA steppe and forest

    Directory of Open Access Journals (Sweden)

    Brian M. Connolly

    2017-02-01

    Full Text Available Factors that cause differential establishment among naturalized, invasive, and native species are inadequately documented, much less often quantified among different communities. We evaluated the effects of seed addition and disturbance (i.e., understory canopy removal on the establishment and seedling biomass among two naturalized, two invasive, and two native species (1 forb, 1 grass in each group within steppe and low elevation forest communities in eastern Washington, USA. Establishment within each plant immigrant class was enhanced by seed addition: naturalized species showed the greatest difference in establishment between seed addition and no seed addition plots, native and invasive species establishment also increased following seed addition but not to the same magnitude as naturalized species. Within seed addition plots, understory canopy disturbance resulted in significant increases in plant establishment (regardless of plant immigration class relative to undisturbed plots and the magnitude of this effect was comparable between steppe and adjacent forest. However, regardless of disturbance treatment fewer invasive plants established in the forest than in the steppe, whereas native and naturalized plant establishment did not differ between the habitats. Individual biomass of naturalized species were consistently greater in disturbed (canopy removed versus undisturbed control plots and naturalized species were also larger in the steppe than in the forest at the time of harvest. Similar trends in plant size were observed for the native and invasive species, but the differences in biomass for these two immigration classes between disturbance treatments and between habitats were not significant. We found that strong limitations of non-native species is correlated with intact canopy cover within the forest understory, likely driven by the direct or indirect consequences of low light transmittance through the arboreal and understory canopy

  20. Plant invasions in mountains: global lessons for better management

    Science.gov (United States)

    Keith L. McDougall; Anzar A. Khuroo; Lloyd L. Loope; Catherine G. Parks; Anibal Pauchard; Zafar A. Reshi; Ian Rushworth; Christoph. Kueffer

    2011-01-01

    Mountains are one of few ecosystems little affected by plant invasions. However, the threat of invasion is likely to increase because of climate change, greater anthropogenic land use, and continuing novel introductions. Preventive management, therefore, will be crucial but can be difficult to promote when more pressing problems are unresolved and predictions are...

  1. Soil modification by invasive plants: Effects on native and invasive species of mixed-grass prairies

    Science.gov (United States)

    Jordan, N.R.; Larson, D.L.; Huerd, S.C.

    2008-01-01

    Invasive plants are capable of modifying attributes of soil to facilitate further invasion by conspecifics and other invasive species. We assessed this capability in three important plant invaders of grasslands in the Great Plains region of North America: leafy spurge (Euphorbia esula), smooth brome (Bromus inermis) and crested wheatgrass (Agropyron cristatum). In a glasshouse, these three invasives or a group of native species were grown separately through three cycles of growth and soil conditioning in both steam-pasteurized and non-pasteurized soils, after which we assessed seedling growth in these soils. Two of the three invasive species, Bromus and Agropyron, exhibited significant self-facilitation via soil modification. Bromus and Agropyron also had significant facilitative effects on other invasives via soil modification, while Euphorbia had significant antagonistic effects on the other invasives. Both Agropyron and Euphorbia consistently suppressed growth of two of three native forbs, while three native grasses were generally less affected. Almost all intra- and interspecific effects of invasive soil conditioning were dependent upon presence of soil biota from field sites where these species were successful invaders. Overall, these results suggest that that invasive modification of soil microbiota can facilitate plant invasion directly or via 'cross-facilitation' of other invasive species, and moreover has potential to impede restoration of native communities after removal of an invasive species. However, certain native species that are relatively insensitive to altered soil biota (as we observed in the case of the forb Linum lewisii and the native grasses), may be valuable as 'nurse'species in restoration efforts. ?? 2007 Springer Science+Business Media B.V.

  2. Chapter 8: Fire and nonnative invasive plants in the Interior West bioregion

    Science.gov (United States)

    Peter M. Rice; Guy R. McPherson; Lisa J. Rew

    2008-01-01

    The Interior West bioregion is bounded on the east by the eastern slope of the Rocky Mountains from Canada south to Mexico and on the west by the eastern foothills of the Cascade Range in Washington and Oregon and the eastern foothills of the Sierra Nevada in California. The bioregion includes the Chihuahuan, Sonoran, and Mojave hot deserts and the Great Basin cold...

  3. 75 FR 55736 - Mark Twain National Forest; Missouri; Integrated Non-Native Invasive Plant Project

    Science.gov (United States)

    2010-09-14

    ... DEPARTMENT OF AGRICULTURE Forest Service Mark Twain National Forest; Missouri; Integrated Non... notice of intent initiates the scoping process, which guides the development of the environmental impact... information to MTNF world wide Web site. Four comment letters were received in response to that solicitation...

  4. 75 FR 60405 - Lincoln National Forest, New Mexico, Integrated Non-Native Invasive Plant Project

    Science.gov (United States)

    2010-09-30

    ... Environmental Impact Statement. SUMMARY: The Lincoln National Forest (LNF) proposes to implement an integrated... by November 29, 2010. The draft environmental impact statement is expected January 2011 and the final environmental impact statement is expected April 2011. ADDRESSES: Send written comments to NNIP Project, Lincoln...

  5. Invasional meltdown in northern lakes: Common carp invasion favors non-native plant species

    Science.gov (United States)

    Disturbances can lead to nonrandom changes in community composition due to interactions between the disturbance and the characteristics of species found in the community or available to colonize, producing both winners and losers of disturbance. When the disturbance is a biologic...

  6. Aliens in Antarctica: Assessing transfer of plant propagules by human visitors to reduce invasion risk

    NARCIS (Netherlands)

    Huiskes, A.H.L.; Gremmen, N.J.M.; Bergstrom, D.M.; Frenot, Y.; Hughes, K.A.; Imura, S.; Kiefer, K.; Lebouvier, M.; Lee, J.E.; Tsujimoto, M.; Ware, C.; Van de Vijver, B.; Chown, S.L.

    2014-01-01

    Despite considerable research on biological invasions, key areas remain poorly explored, especially ways to reduce unintentional propagule transfer. The Antarctic represents a microcosm of the situation, with the numbers of established non-native species growing. Information to help reduce potential

  7. Invasive and native plant responses to shrubland fuel reduction: comparing prescribed fire, mastication, and treatment season

    Science.gov (United States)

    Jennifer B. Potts; Scott L. Stephens

    2009-01-01

    Fuel reduction in the wildland–urban interface is a widely used international strategy for assisting human communities regarding wildfire threats, but very little research has examined whether certain fuel reduction methods and their seasonal timing promote nonnative invasion. To...

  8. Mechanisms for dominance in an early successional old field by the invasive non-native Lespedeza cuneata (Dum. Cours.) G. Don

    Science.gov (United States)

    Brandon, A.L.; Gibson, D.J.; Middleton, B.A.

    2004-01-01

    Researchers studying invasive plants often concentrate their efforts on predictive models thought to allow invasive plants to dominate native landscapes. However, if an invasive is already well established then experimental research is necessary to provide the information necessary to effectively manage the species. Prescribing appropriate management strategies without prior experimental research may not only be ineffective but also may squander limited resources or have the unintended consequence of furthering spread. Lespedeza cuneata (Dum. Cours.) G. Don. is a well-established invasive plant of old fields and tall-grass prairie in the US. Managers suspect this species shades-out native plants and this is proposed as its primary mechanism for dominance. Using field experiments we tested probable factors allowing the speices to establish itself and once established, interfere in old field plant communities. We also examined the effects of two common anthropogenic disturbances (mowing and nutrients) on L. cuneata growth and establishment. When L. cuneata was treated (clipping, herbicide and stem pull-back) there was a significant increase in species richness and native speices cover. Stem density and canopy cover of L. cuneata increased significantly with mowing frequency but decreased with nutrient input. We suggest that mowing benefits L. cuneata while also hindering woody competition. Results also indicate L. cuneata is less prevalent on nutrient enriched soils than on unamended soil. Lespedeza cuneata appears to suppress native plants by shading them out and it can subsequently take over grassland communities. Since it has a varying response to human induced disturbances and may actually benefit from mowing, land managers should be cautious when utilizing this as a management tool.

  9. Soil seed banks in plant invasions: promoting species invasiveness and long-term impakt on plant community dynamics

    Czech Academy of Sciences Publication Activity Database

    Gioria, M.; Pyšek, Petr; Moravcová, Lenka

    2012-01-01

    Roč. 84, č. 2 (2012), s. 327-350 ISSN 0032-7786 R&D Projects: GA ČR GA206/09/0563 Institutional support: RVO:67985939 Keywords : soil seed bank * plant invasions * species invasive ness Subject RIV: EF - Botanics Impact factor: 2.833, year: 2012

  10. Invaders in hot water: a simple decontamination method to prevent the accidental spread of aquatic invasive non-native species.

    Science.gov (United States)

    Anderson, Lucy G; Dunn, Alison M; Rosewarne, Paula J; Stebbing, Paul D

    Watersports equipment can act as a vector for the introduction and spread of invasive non native species (INNS) in freshwater environments. To support advice given to recreational water users under the UK Government's Check Clean Dry biosecurity campaign and ensure its effectiveness at killing a range of aquatic INNS, we conducted a survival experiment on seven INNS which pose a high risk to UK freshwaters. The efficacy of exposure to hot water (45 °C, 15 min) was tested as a method by which waters users could 'clean' their equipment and was compared to drying and a control group (no treatment). Hot water had caused 99 % mortality across all species 1 h after treatment and was more effective than drying at all time points (1 h: χ 2  = 117.24, p  clean equipment. We recommend that it is advocated in future biosecurity awareness campaigns.

  11. Do invasive alien plants benefit more from global environmental change than native plants?

    Science.gov (United States)

    Liu, Yanjie; Oduor, Ayub M O; Zhang, Zhen; Manea, Anthony; Tooth, Ifeanna M; Leishman, Michelle R; Xu, Xingliang; van Kleunen, Mark

    2017-08-01

    Invasive alien plant species threaten native biodiversity, disrupt ecosystem functions and can cause large economic damage. Plant invasions have been predicted to further increase under ongoing global environmental change. Numerous case studies have compared the performance of invasive and native plant species in response to global environmental change components (i.e. changes in mean levels of precipitation, temperature, atmospheric CO 2 concentration or nitrogen deposition). Individually, these studies usually involve low numbers of species and therefore the results cannot be generalized. Therefore, we performed a phylogenetically controlled meta-analysis to assess whether there is a general pattern of differences in invasive and native plant performance under each component of global environmental change. We compiled a database of studies that reported performance measures for 74 invasive alien plant species and 117 native plant species in response to one of the above-mentioned global environmental change components. We found that elevated temperature and CO 2 enrichment increased the performance of invasive alien plants more strongly than was the case for native plants. Invasive alien plants tended to also have a slightly stronger positive response to increased N deposition and increased precipitation than native plants, but these differences were not significant (N deposition: P = 0.051; increased precipitation: P = 0.679). Invasive alien plants tended to have a slightly stronger negative response to decreased precipitation than native plants, although this difference was also not significant (P = 0.060). So while drought could potentially reduce plant invasion, increases in the four other components of global environmental change considered, particularly global warming and atmospheric CO 2 enrichment, may further increase the spread of invasive plants in the future. © 2017 John Wiley & Sons Ltd.

  12. INVENTORY OF THE INVASIVE ALIE N PLANT SPECIES IN INDONESIA

    Directory of Open Access Journals (Sweden)

    SRI S UDARMIYATI T JITROSOEDIRDJO

    2005-01-01

    Full Text Available An inventory of the alien plant species in Indone sia based on the existing references and herbarium specimens concluded that 1936 alien plant species ar e found in Indonesia which belong to 187 families. Field studies should be done to get the complete figur es of alien plant species in Indonesia. Based on the existing figures of the plant species, the invasive alien plant species can be iden tified, followed by studies on the assessment of losses, biology, management and their possible utilizations. Alien plant species are imported to Indonesia for cultivation, collection of the botanical garden, as experimental plants or other curiosities. Aside from plants purposely imported, there are also introduced plant propagules conta-minating imported agricultural products. These alien plant species can be beneficial or have a potential of being invasive. The alien cultivated species consisted of 67% of the total number. More than half of the cultivated plants are ornamental plants. Some of th e species are naturalized or escaped from cultivation and become wild and invasive. Some other natura lized species, adapted well without any problems of invasion. There are 339 species or 17% of the species r ecorded as weeds. The highest record of weeds is found in the family of Poaceae (57 species, follo wed by Asteraceae (53 species and Cyperaceae (35 species. There are 6 families having more than 10 species of weeds: Amaranthaceae, Asteraceae, Cyperaceae, Euphorbiaceae, Poaceae, and Rubiaceae. Three families have more than 100 species: Asteraceae 162 species, Poaceae 120 species, and Papillionaceae 103 species. Five species of aquatic and 20 species of terrestrial plants considered as important alien plant species in Indonesia were identified and some of their distributions noted

  13. Using habitat suitability models to target invasive plant species surveys.

    Science.gov (United States)

    Crall, Alycia W; Jarnevich, Catherine S; Panke, Brendon; Young, Nick; Renz, Mark; Morisette, Jeffrey

    2013-01-01

    Managers need new tools for detecting the movement and spread of nonnative, invasive species. Habitat suitability models are a popular tool for mapping the potential distribution of current invaders, but the ability of these models to prioritize monitoring efforts has not been tested in the field. We tested the utility of an iterative sampling design (i.e., models based on field observations used to guide subsequent field data collection to improve the model), hypothesizing that model performance would increase when new data were gathered from targeted sampling using criteria based on the initial model results. We also tested the ability of habitat suitability models to predict the spread of invasive species, hypothesizing that models would accurately predict occurrences in the field, and that the use of targeted sampling would detect more species with less sampling effort than a nontargeted approach. We tested these hypotheses on two species at the state scale (Centaurea stoebe and Pastinaca sativa) in Wisconsin (USA), and one genus at the regional scale (Tamarix) in the western United States. These initial data were merged with environmental data at 30-m2 resolution for Wisconsin and 1-km2 resolution for the western United States to produce our first iteration models. We stratified these initial models to target field sampling and compared our models and success at detecting our species of interest to other surveys being conducted during the same field season (i.e., nontargeted sampling). Although more data did not always improve our models based on correct classification rate (CCR), sensitivity, specificity, kappa, or area under the curve (AUC), our models generated from targeted sampling data always performed better than models generated from nontargeted data. For Wisconsin species, the model described actual locations in the field fairly well (kappa = 0.51, 0.19, P guiding invasive species monitoring, and we support the use of an iterative sampling design for

  14. Positive and Negative Impacts of Non-Native Bee Species around the World.

    Science.gov (United States)

    Russo, Laura

    2016-11-28

    Though they are relatively understudied, non-native bees are ubiquitous and have enormous potential economic and environmental impacts. These impacts may be positive or negative, and are often unquantified. In this manuscript, I review literature on the known distribution and environmental and economic impacts of 80 species of introduced bees. The potential negative impacts of non-native bees include competition with native bees for nesting sites or floral resources, pollination of invasive weeds, co-invasion with pathogens and parasites, genetic introgression, damage to buildings, affecting the pollination of native plant species, and changing the structure of native pollination networks. The potential positive impacts of non-native bees include agricultural pollination, availability for scientific research, rescue of native species, and resilience to human-mediated disturbance and climate change. Most non-native bee species are accidentally introduced and nest in stems, twigs, and cavities in wood. In terms of number of species, the best represented families are Megachilidae and Apidae, and the best represented genus is Megachile . The best studied genera are Apis and Bombus , and most of the species in these genera were deliberately introduced for agricultural pollination. Thus, we know little about the majority of non-native bees, accidentally introduced or spreading beyond their native ranges.

  15. Positive and Negative Impacts of Non-Native Bee Species around the World

    Directory of Open Access Journals (Sweden)

    Laura Russo

    2016-11-01

    Full Text Available Though they are relatively understudied, non-native bees are ubiquitous and have enormous potential economic and environmental impacts. These impacts may be positive or negative, and are often unquantified. In this manuscript, I review literature on the known distribution and environmental and economic impacts of 80 species of introduced bees. The potential negative impacts of non-native bees include competition with native bees for nesting sites or floral resources, pollination of invasive weeds, co-invasion with pathogens and parasites, genetic introgression, damage to buildings, affecting the pollination of native plant species, and changing the structure of native pollination networks. The potential positive impacts of non-native bees include agricultural pollination, availability for scientific research, rescue of native species, and resilience to human-mediated disturbance and climate change. Most non-native bee species are accidentally introduced and nest in stems, twigs, and cavities in wood. In terms of number of species, the best represented families are Megachilidae and Apidae, and the best represented genus is Megachile. The best studied genera are Apis and Bombus, and most of the species in these genera were deliberately introduced for agricultural pollination. Thus, we know little about the majority of non-native bees, accidentally introduced or spreading beyond their native ranges.

  16. Plant invasions in mountains: Global lessons for better management

    Science.gov (United States)

    McDougall, K.L.; Khuroo, A.A.; Loope, L.L.; Parks, C.G.; Pauchard, A.; Reshi, Z.A.; Rushworth, I.; Kueffer, C.

    2011-01-01

    Mountains are one of few ecosystems little affected by plant invasions. However, the threat of invasion is likely to increase because of climate change, greater anthropogenic land use, and continuing novel introductions. Preventive management, therefore, will be crucial but can be difficult to promote when more pressing problems are unresolved and predictions are uncertain. In this essay, we use management case studies from 7 mountain regions to identify common lessons for effective preventive action. The degree of plant invasion in mountains was variable in the 7 regions as was the response to invasion, which ranged from lack of awareness by land managers of the potential impact in Chile and Kashmir to well-organized programs of prevention and containment in the United States (Hawaii and the Pacific Northwest), including prevention at low altitude. In Australia, awareness of the threat grew only after disruptive invasions. In South Africa, the economic benefits of removing alien plants are well recognized and funded in the form of employment programs. In the European Alps, there is little need for active management because no invasive species pose an immediate threat. From these case studies, we identify lessons for management of plant invasions in mountain ecosystems: (i) prevention is especially important in mountains because of their rugged terrain, where invasions can quickly become unmanageable; (ii) networks at local to global levels can assist with awareness raising and better prioritization of management actions; (iii) the economic importance of management should be identified and articulated; (iv) public acceptance of management programs will make them more effective; and (v) climate change needs to be considered. We suggest that comparisons of local case studies, such as those we have presented, have a pivotal place in the proactive solution of global change issues. ?? International Mountain Society.

  17. Loss of native herbaceous species due to woody plant encroachment facilitates the establishment of an invasive grass.

    Science.gov (United States)

    Alofs, Karen M; Fowler, Norma L

    2013-03-01

    Although negative relationships between diversity (frequently measured as species richness) and invasibility at neighborhood or community scales have often been reported, realistic natural diversity gradients have rarely been studied at this scale. We recreated a naturally occurring gradient in species richness to test the effects of species richness on community invasibility. In central Texas savannas, as the proportion of woody plants increases (a process known as woody plant encroachment), herbaceous habitat is both lost and fragmented, and native herbaceous species richness declines. We examined the effects of these species losses on invasibility in situ by removing species that occur less frequently in herbaceous patches as woody plant encroachment advances. This realistic species removal was accompanied by a parallel and equivalent removal of biomass with no changes in species richness. Over two springs, the nonnative bunchgrass Bothriochloa ischaemum germinated significantly more often in the biomass-removal treatment than in unmanipulated control plots, suggesting an effect of native plant density independent of diversity. Additionally, significantly more germination occurred in the species-removal treatment than in the biomass-removal treatment. Changes in species richness had a stronger effect on B. ischaemum germination than changes in plant density, demonstrating that niche-related processes contributed more to biotic resistance in this system than did species-neutral competitive interactions. Similar treatment effects were found on transplant growth. Thus we show that woody plant encroachment indirectly facilitates the establishment of an invasive grass by reducing native diversity. Although we found a negative relationship between species richness and invasibility at the scale of plots with similar composition and environmental conditions, we found a positive relationship between species richness and invasibility at larger scales. This apparent

  18. The changing role of ornamental horticulture in alien plant invasions.

    Science.gov (United States)

    van Kleunen, Mark; Essl, Franz; Pergl, Jan; Brundu, Giuseppe; Carboni, Marta; Dullinger, Stefan; Early, Regan; González-Moreno, Pablo; Groom, Quentin J; Hulme, Philip E; Kueffer, Christoph; Kühn, Ingolf; Máguas, Cristina; Maurel, Noëlie; Novoa, Ana; Parepa, Madalin; Pyšek, Petr; Seebens, Hanno; Tanner, Rob; Touza, Julia; Verbrugge, Laura; Weber, Ewald; Dawson, Wayne; Kreft, Holger; Weigelt, Patrick; Winter, Marten; Klonner, Günther; Talluto, Matthew V; Dehnen-Schmutz, Katharina

    2018-03-05

    The number of alien plants escaping from cultivation into native ecosystems is increasing steadily. We provide an overview of the historical, contemporary and potential future roles of ornamental horticulture in plant invasions. We show that currently at least 75% and 93% of the global naturalised alien flora is grown in domestic and botanical gardens, respectively. Species grown in gardens also have a larger naturalised range than those that are not. After the Middle Ages, particularly in the 18th and 19th centuries, a global trade network in plants emerged. Since then, cultivated alien species also started to appear in the wild more frequently than non-cultivated aliens globally, particularly during the 19th century. Horticulture still plays a prominent role in current plant introduction, and the monetary value of live-plant imports in different parts of the world is steadily increasing. Historically, botanical gardens - an important component of horticulture - played a major role in displaying, cultivating and distributing new plant discoveries. While the role of botanical gardens in the horticultural supply chain has declined, they are still a significant link, with one-third of institutions involved in retail-plant sales and horticultural research. However, botanical gardens have also become more dependent on commercial nurseries as plant sources, particularly in North America. Plants selected for ornamental purposes are not a random selection of the global flora, and some of the plant characteristics promoted through horticulture, such as fast growth, also promote invasion. Efforts to breed non-invasive plant cultivars are still rare. Socio-economical, technological, and environmental changes will lead to novel patterns of plant introductions and invasion opportunities for the species that are already cultivated. We describe the role that horticulture could play in mediating these changes. We identify current research challenges, and call for more

  19. PLANT INVASIONS IN RHODE ISLAND RIPARIAN ZONES

    Science.gov (United States)

    The vegetation in riparian zones provides valuable wildlife habitat while enhancing instream habitat and water quality. Forest fragmentation, sunlit edges, and nutrient additions from adjacent development may be sources of stress on riparian zones. Landscape plants may include no...

  20. A review of impacts by invasive exotic plants on forest ecosystem services

    Science.gov (United States)

    Kevin Devine; Songlin. Fei

    2011-01-01

    Many of our forest ecosystems are at risk due to the invasion of exotic invasive plant species. Invasive plant species pose numerous threats to ecosystems by decreasing biodiversity, deteriorating ecosystem processes, and degrading ecosystem services. Literature on Kentucky's most invasive exotic plant species was examined to understand their potential impacts on...

  1. Alien plant invasions and native plant extinctions: a six-threshold framework.

    Science.gov (United States)

    Downey, Paul O; Richardson, David M

    2016-01-01

    Biological invasions are widely acknowledged as a major threat to global biodiversity. Species from all major taxonomic groups have become invasive. The range of impacts of invasive taxa and the overall magnitude of the threat is increasing. Plants comprise the biggest and best-studied group of invasive species. There is a growing debate; however, regarding the nature of the alien plant threat-in particular whether the outcome is likely to be the widespread extinction of native plant species. The debate has raised questions on whether the threat posed by invasive plants to native plants has been overstated. We provide a conceptual framework to guide discussion on this topic, in which the threat posed by invasive plants is considered in the context of a progression from no impact through to extinction. We define six thresholds along the 'extinction trajectory', global extinction being the final threshold. Although there are no documented examples of either 'in the wild' (Threshold 5) or global extinctions (Threshold 6) of native plants that are attributable solely to plant invasions, there is evidence that native plants have crossed or breached other thresholds along the extinction trajectory due to the impacts associated with plant invasions. Several factors may be masking where native species are on the trajectory; these include a lack of appropriate data to accurately map the position of species on the trajectory, the timeframe required to definitively state that extinctions have occurred and management interventions. Such interventions, focussing mainly on Thresholds 1-3 (a declining population through to the local extinction of a population), are likely to alter the extinction trajectory of some species. The critical issue for conservation managers is the trend, because interventions must be implemented before extinctions occur. Thus the lack of evidence for extinctions attributable to plant invasions does not mean we should disregard the broader threat

  2. Alien plant invasions and native plant extinctions: a six-threshold framework

    Science.gov (United States)

    Downey, Paul O.; Richardson, David M.

    2016-01-01

    Biological invasions are widely acknowledged as a major threat to global biodiversity. Species from all major taxonomic groups have become invasive. The range of impacts of invasive taxa and the overall magnitude of the threat is increasing. Plants comprise the biggest and best-studied group of invasive species. There is a growing debate; however, regarding the nature of the alien plant threat—in particular whether the outcome is likely to be the widespread extinction of native plant species. The debate has raised questions on whether the threat posed by invasive plants to native plants has been overstated. We provide a conceptual framework to guide discussion on this topic, in which the threat posed by invasive plants is considered in the context of a progression from no impact through to extinction. We define six thresholds along the ‘extinction trajectory’, global extinction being the final threshold. Although there are no documented examples of either ‘in the wild’ (Threshold 5) or global extinctions (Threshold 6) of native plants that are attributable solely to plant invasions, there is evidence that native plants have crossed or breached other thresholds along the extinction trajectory due to the impacts associated with plant invasions. Several factors may be masking where native species are on the trajectory; these include a lack of appropriate data to accurately map the position of species on the trajectory, the timeframe required to definitively state that extinctions have occurred and management interventions. Such interventions, focussing mainly on Thresholds 1–3 (a declining population through to the local extinction of a population), are likely to alter the extinction trajectory of some species. The critical issue for conservation managers is the trend, because interventions must be implemented before extinctions occur. Thus the lack of evidence for extinctions attributable to plant invasions does not mean we should disregard the broader

  3. SEASONALITY OF ANNUAL PLANT ESTABLISHMENT INFLUENCES THE INTERACTIONBETWEEN THE NON-NATIVE ANNUAL GRASS BROMUS MADRITENSIS SSP. RUBENS AND MOJAVE DESERT PERENNIALS

    Energy Technology Data Exchange (ETDEWEB)

    L A. DEFALCO; G. C. FERNANDEZ; R. S. NOWAK

    2004-01-01

    Competition between native and non-native species can change the composition and structure of plant communities, but in deserts the timing of non-native plant establishment can modulate their impacts to native species. In a field experiment, we varied densities of the non-native annual grass Bromus madritensis ssp. rubens around individuals of three native perennials--Larrea iridentata, Achnatherum hymenoides, and Pleuraphis rigida--in either winter or spring. Additional plots were prepared for the Same perennial species and seasons, but with a mixture of native annual species. Relative growth rates of perennial shoots (RGRs) declined with increasing Bromus biomass when Bromus that was established in winter had 2-3 mo of growth and high water use before perennial growth began. However, this high water use did not significantly reduce water potentials for the perennials, suggesting Bromus that established earlier depleted other soil resources, such as N, otherwise used by perennial plants. Spring-established Bromus had low biomass even at higher densities and did not effectively reduce RGRs, resulting in an overall lower impact to perennials than when Bromus was established in winter. Similarly, growth and reproduction of perennials with mixed annuals as neighbors did not differ from those with Bromus neighbors of equivalent biomass, but densities of these annuals did not support the high biomass necessary to reduce perennial growth. Thus, impacts of native Mojave Desert annuals to perennials are expected to be lower than those of Bromus because seed dormancy and narrow requirements for seedling survivorship produce densities and biomass lower than those achieved by Bromus. In comparing the effects of Bromus among perennial species, the impact of increased Bromus biomass on RGR was lower for Larrea than for the two perennial grasses, probably because Lurrea maintains low growth rates throughout the year, even after Bromus has completed its life cycle. This contrasts

  4. Effects of invasive alien kahili ginger (Hedychium gardnerianum) on native plant species regeneration in a Hawaiian rainforest

    Science.gov (United States)

    Minden, V.; Jacobi, J.D.; Porembski, S.; Boehmer, H.J.

    2010-01-01

    Questions: Does the invasive alien Hedychium gardnerianum (1) replace native understory species, (2) suppress natural regeneration of native plant species, (3) increase the invasiveness of other non-native plants and (4) are native forests are able to recover after removal of H. gardnerianum. Location: A mature rainforest in Hawai'i Volcanoes National Park on the island of Hawai'i (about 1200 m. a.s.l.; precipitation approximately 2770mm yr-1). Study sites included natural plots without effects of alien plants, ginger plots with a H. gardnerianum-domimted herb layer and cleared plots treated with herbicide to remove alien plants. Methods: Counting mature trees, saplings and seedlings of native and alien plant species. Using nonparametric H-tests to compare impact of H. gardnerianum on the structure of different sites. Results: Results confirmed the hypothesis that H. gardnerianum has negative effects on natural forest dynamics. Lower numbers of native tree seedlings and saplings were found on ginger-dominated plots. Furthermore, H. gardnerianum did not show negative effects on the invasive alien tree species Psidium cattleianum. Conclusions: This study reveals that where dominance of H. gardnerianum persists, regeneration of the forest by native species will be inhibited. Furthermore, these areas might experience invasion by P. cattleianum, resulting in displacement of native canopy species in the future, leading to a change in forest structure and loss of other species dependent on natural rainforest, such as endemic birds. However, if H. gardnerianum is removed the native Hawaiian forest is likely to regenerate and regain its natural structure. ?? 2009 International Association for Vegetation Science.

  5. Uprooting and burial of invasive alien plants

    DEFF Research Database (Denmark)

    Kollmann, Johannes Christian; Brink-Jensen, Kasper; Frandsen, Sally I.

    2011-01-01

    (Japanese Rose), an invasive shrub in north-western Europe with negative effects on coastal biodiversity. Two months after uprooting and burial in dunes of north-eastern Denmark, 89% of the 58 shrubs resprouted from roots and rhizomes; on average 41 resprouts per shrub. Resprout density was twice as high...... at former shrub margins compared with the center; resprouts were taller and originated from more superficial soil layers at the margin than in the center. Resprouting was negatively correlated with fragment depth, and no resprouts were observed from greater than 15 cm depth. The number of resprouts...... increased with fragment dry mass (0.5–168.5 g). After 18 months with harrowing the species was still resprouting, flowering, and fruiting, albeit with no difference between shrub margin and center. Resprouts were taller (26 cm) and coverage was higher (0–4%) after two compared with three times harrowing...

  6. Quantifying "apparent" impact and distinguishing impact from invasiveness in multispecies plant invasions

    Science.gov (United States)

    Dean E. Pearson; Yvette K. Ortega; Ozkan Eren; Jose L. Hierro

    2015-01-01

    The quantification of invader impacts remains a major hurdle to understanding and managing invasions. Here, we demonstrate a method for quantifying the community-level impact of multiple plant invaders by applying Parker et al.'s (1999) equation (impact = range x local abundance x per capita effect or per unit effect) using data from 620 survey plots from 31...

  7. Efficient distinction of invasive aquatic plant species from non-invasive related species using DNA barcoding.

    Science.gov (United States)

    Ghahramanzadeh, R; Esselink, G; Kodde, L P; Duistermaat, H; van Valkenburg, J L C H; Marashi, S H; Smulders, M J M; van de Wiel, C C M

    2013-01-01

    Biological invasions are regarded as threats to global biodiversity. Among invasive aliens, a number of plant species belonging to the genera Myriophyllum, Ludwigia and Cabomba, and to the Hydrocharitaceae family pose a particular ecological threat to water bodies. Therefore, one would try to prevent them from entering a country. However, many related species are commercially traded, and distinguishing invasive from non-invasive species based on morphology alone is often difficult for plants in a vegetative stage. In this regard, DNA barcoding could become a good alternative. In this study, 242 samples belonging to 26 species from 10 genera of aquatic plants were assessed using the chloroplast loci trnH-psbA, matK and rbcL. Despite testing a large number of primer sets and several PCR protocols, the matK locus could not be amplified or sequenced reliably and therefore was left out of the analysis. Using the other two loci, eight invasive species could be distinguished from their respective related species, a ninth one failed to produce sequences of sufficient quality. Based on the criteria of universal application, high sequence divergence and level of species discrimination, the trnH-psbA noncoding spacer was the best performing barcode in the aquatic plant species studied. Thus, DNA barcoding may be helpful with enforcing a ban on trade of such invasive species, such as is already in place in the Netherlands. This will become even more so once DNA barcoding would be turned into machinery routinely operable by a nonspecialist in botany and molecular genetics. © 2012 Blackwell Publishing Ltd.

  8. Can transgenerational plasticity contribute to the invasion success of annual plant species?

    Science.gov (United States)

    Fenesi, Annamária; Dyer, Andrew R; Geréd, Júliánna; Sándor, Dorottya; Ruprecht, Eszter

    2014-09-01

    Adaptive transgenerational plasticity (TGP), i.e., significantly higher fitness when maternal and offspring conditions match, might contribute to the population growth of non-native species in highly variable environments. However, comparative studies that directly test this hypothesis are lacking. Therefore, we performed a reciprocal split-brood experiment to compare TGP in response to N and water availability in single populations of two invasive (Amaranthus retroflexus, Galinsoga parviflora) and two congeneric non-invasive introduced species (Amaranthus albus, Galinsoga ciliata). We hypothesized that the transgenerational effect is adaptive: (1) in invasive species compared with non-invasive adventives, and (2) in stressful conditions compared with resource-rich environments. The phenotypic variation among offspring was generated, in large part, by our experimental treatments in the maternal generation; therefore, we demonstrated a direct TGP effect on the offspring's adult fitness. We found evidence, for the first time, that invasive and non-invasive adventive species differ regarding the expression of TGP in the adult stage, as adaptive responses were found exclusively in the invasive species. The manifestation of TGP was more explicit under resource-rich conditions; therefore, it might contribute to the population dynamics of non-native species in resource-rich sites rather than to their ecological tolerance spectra.

  9. Ecological disequilibrium drives insect pest and pathogen accumulation in non-native trees.

    Science.gov (United States)

    Crous, Casparus J; Burgess, Treena I; Le Roux, Johannes J; Richardson, David M; Slippers, Bernard; Wingfield, Michael J

    2016-12-23

    Non-native trees have become dominant components of many landscapes, including urban ecosystems, commercial forestry plantations, fruit orchards, and as invasives in natural ecosystems. Often, these trees have been separated from their natural enemies (i.e. insects and pathogens) leading to ecological disequilibrium, that is, the immediate breakdown of historically co-evolved interactions once introduced into novel environments. Long-established, non-native tree plantations provide useful experiments to explore the dimensions of such ecological disequilibria. We quantify the status quo of non-native insect pests and pathogens catching up with their tree hosts (planted Acacia, Eucalyptus and Pinus species) in South Africa, and examine which native South African enemy species utilise these trees as hosts. Interestingly, pines, with no confamilial relatives in South Africa and the longest residence time (almost two centuries), have acquired only one highly polyphagous native pathogen. This is in contrast to acacias and eucalypts, both with many native and confamilial relatives in South Africa that have acquired more native pathogens. These patterns support the known role of phylogenetic relatedness of non-native and native floras in influencing the likelihood of pathogen shifts between them. This relationship, however, does not seem to hold for native insects. Native insects appear far more likely to expand their feeding habits onto non-native tree hosts than are native pathogens, although they are generally less damaging. The ecological disequilibrium conditions of non-native trees are deeply rooted in the eco-evolutionary experience of the host plant, co-evolved natural enemies, and native organisms from the introduced range. We should expect considerable spatial and temporal variation in ecological disequilibrium conditions among non-native taxa, which can be significantly influenced by biosecurity and management practices. Published by Oxford University Press on

  10. Satellite-based annual evaporation estimates of invasive alien plant ...

    African Journals Online (AJOL)

    ... of densely-invaded riparian areas is likely more pronounced. We concluded that the clearing of IAPs by the WFW programme has a positive effect on the availability of water resources through a reduction in ET. Keywords: invasive alien plants; indigenous vegetation; remote sensing; water use; evapotranspiration; SEBAL; ...

  11. Assessing stakeholder perspectives on invasive plants to inform risk analysis

    Science.gov (United States)

    Conservation and land management decisions are often based primarily on natural science, but could be more successful if human influences were effectively integrated into decision-making. This is especially true for efforts to manage invasive plants, whose arrival is usually the product of delibera...

  12. Scientific challenges in the field of invasive alien plant management

    CSIR Research Space (South Africa)

    Van Wilgen, BW

    2004-01-01

    Full Text Available This article examines scientific challenges in the field of invasion alien plant management in South Africa. Overview of the Working for Water program, Issues of research funding, and Biological control research. It also includes some of the papers...

  13. Managing invasive plants in natural areas: Moving beyond weed control

    Science.gov (United States)

    Dean Pearson; Yvette Ortega

    2009-01-01

    Exotic invasive plants present one of the greatest challenges to natural resource management. These weeds can alter entire communities and ecosystems, substantially degrading important ecosystem services such as forage for wild and domestic herbivores, water and soil quality, recreational values, and wildlife habitat. Traditionally, weed management in natural areas has...

  14. The importance of education in managing invasive plant species

    Science.gov (United States)

    Invasive plant species can establish in diverse environments and with the increase in human mobility, they are no longer restricted to isolated pockets in remote parts of the world. Cheat grass (Bromus tectorum L.) in rangelands, purple loosestrife (Lythrum salicaria L.) in wet lands and Canada this...

  15. AIRBORNE HYPERSPECTRAL IDENTIFICATION OF INVASIVE AND OPPORTUNISTIC WETLANDS PLANT SPECIES

    Science.gov (United States)

    Coastal wetlands are among the most fragmented and disturbed ecosystems and the Great Lakes are no exception. One possible result is the observed increase in the presence and dominance of invasive and other opportunistic plant species, such as the common reed (Phragmites australi...

  16. Hydrothermal processing of biomass from invasive aquatic plants

    Science.gov (United States)

    W. James Catallo; Todd F. Shupe; Thomas L. Eberhardt

    2008-01-01

    The purpose of this study was to examine the hydrothermal (HT) treatment of three invasive aquatic plants (i.e., Lemna sp., Hydrilla sp., and Eichhornia sp.) with respect to the generation of semi-volatile hydrocarbon product mixtures and biomass volume reduction. Identical HT treatments yielded similar semi-...

  17. Beyond theories of plant invasions: Lessons from natural landscapes

    Science.gov (United States)

    Stohlgren, Thomas J.

    2002-01-01

    There are a growing number of contrasting theories about plant invasions, but most are only weakly supported by small-scale field experiments, observational studies, and mathematical models. Among the most contentious theories is that species-rich habitats should be less vulnerable to plant invasion than species-poor sites, stemming from earlier theories that competition is a major force in structuring plant communities. Early ecologists such as Charles Darwin (1859) and Charles Elton (1958) suggested that a lack of intense interspecific competition on islands made these low-diversity habitats vulnerable to invasion. Small-scale field experiments have supported and contradicted this theory, as have various mathematical models. In contrast, many large-scale observational studies and detailed vegetation surveys in continental areas often report that species-rich areas are more heavily invaded than species-poor areas, but there are exceptions here as well. In this article, I show how these seemingly contrasting patterns converge once appropriate spatial and temporal scales are considered in complex natural environments. I suggest ways in which small-scale experiments, mathematical models, and large- scale observational studies can be improved and better integrated to advance a theoretically based understanding of plant invasions.

  18. Geographic extent and chronology of the invasion of non-native lionfish (Pterois volitans [Linnaeus 1758] and P. miles [Bennett 1828]) in the Western North Atlantic and Caribbean Sea

    Science.gov (United States)

    Schofield, Pamela J.

    2009-01-01

    The Indo-Pacific lionfishes (Pterois volitans [Linnaeus 1758] and P. miles [Bennett 1828]: Family Scorpaenidae) are the first non-native marine fishes to establish in the Western North Atlantic. The chronology of the invasion is reported here using records from the US Geological Survey's Nonindigenous Aquatic Species database. Currently, lionfish are established off the Atlantic coast of the USA from the Florida Keys to Cape Hatteras (North Carolina), the Great Antilles, Bermuda, Bahamas, Cayman Islands and Turks and Caicos. The species have been reported from only one island in the Lesser Antilles (St. Croix), but it is not yet established there. Lionfish are established in Mexico, Honduras and Costa Rica. Reports have come from the Gulf of Mexico (Florida), Belize, Panama and Colombia; although lionfish are not considered established in these localities at this time (August 2009), invasion is likely imminent.

  19. Climatic niche of Selinum alatum (Apiaceae, Selineae), a new invasive plant species in Central Europe and its alterations according to the climate change scenarios: Are the European mountains threatened by invasion?

    Science.gov (United States)

    Konowalik, Kamil; Proćków, Małgorzata; Proćków, Jarosław

    2017-01-01

    In recent years, a few established populations of Selinum alatum have been found in the Eastern Carpathians outside its native range that is the Caucasus and the Armenian Highlands. The species is spreading predominantly in Poland where it can outcompete native plants in certain cases. This study addresses a potential climatic niche of the plant with the special aims to illuminate future spreading and indicate areas suitable for invasion. Our results show that the extent of the favourable habitat of the species is broader than currently known. This suggests that the plant has the ability to become a potential new element in some semi-natural or disturbed ecosystems associated with mountainous areas, especially in Central and Southern Europe. Future (2070) models mostly rendered similar suitability maps, but showed slight differences over particular areas and a contraction of suitable habitats, mainly in the northern part of the non-native range.

  20. Modelling plant invasion pathways in protected areas under climate change: implication for invasion management

    Directory of Open Access Journals (Sweden)

    C.-J. Wang

    2017-12-01

    Full Text Available Global climate change may enable invasive plant species (IPS to invade protected areas (PAs, but plant invasion on a global scale has not yet been explicitly addressed. Here, we mapped the potential invasion pathways for IPS in PAs across the globe and explored potential factors determining the pathways of plant invasion under climate change. We used species distribution modelling to estimate the suitable habitats of 386 IPS and applied a corridor analysis to compute the potential pathways of IPS in PAs under climate change. Subsequently, we analysed the potential factors affecting the pathways in PAs. According to our results, the main potential pathways of IPS in PAs are in Europe, eastern Australia, New Zealand, southern Africa, and eastern regions of South America and are strongly influenced by changes in temperature and precipitation. Protected areas can play an important role in preventing and controlling the spread of IPS under climate change. This is due to the fact that measures are taken to monitor climate change in detail, to provide effective management near or inside PAs, and to control the introduction of IPS with a high capacity for natural dispersal. A review of conservation policies in PAs is urgently needed.

  1. Non-native Species in Floodplain Secondary Forests in Peninsular Malaysia

    Directory of Open Access Journals (Sweden)

    Nor Rasidah Hashim

    2010-01-01

    Full Text Available There is an increasing concern of alien species invading our tropical ecosystems because anthropogenic land use can create conditions in which non-native species thrive. This study is an assessment of bioinvasion using a quantitative survey of non-native plant species in floodplain secondary forests in Peninsular Malaysia. The study area is known to have a long cultivation and settlement history that provides ample time for non-native species introduction. The survey results showed that introduced species constituted 23% of all the identified species, with seven species unique to riparian forest strips and eleven species unique to abandoned paddy fields and the remaining five species being shared between the two secondary forest types. There existed some habitat preferences amongst the species implying both secondary forests were potentially susceptible to bioinvasion. Fourteen species are also invasive elsewhere (PIER invasives whereas fifteen species have acquired local uses such for traditional medicine and food products. The presence of these non-native species could alter native plant succession trajectory, and eventually leads to native species impoverishment if the exotics managed to outcompete the native species. As such, the findings of this study have a far-reaching application for the national biodiversity conservation efforts because it provides the required information on bioinvasion.

  2. Allelopathic potential of segetal and ruderal invasive alien plants

    Directory of Open Access Journals (Sweden)

    Nenad Novak

    2018-06-01

    Full Text Available At the global level, the invasion of alien organisms is considered the second largest threat to biodiversity. The assumption is that the high allelopathic potential is one of the features that helps invasive plant species to spread to new areas. Allelopathic potential of 8 invasive plant species (donor species and their impact on test-species was determined in the study. Donor species were velvetleaf (Abutilon theophrasti Med., ragweed (Ambrosia elatior L., jimsonweed (Datura stramonium L., common cocklebur (Xanthium strumarium L., tree of heaven (Ailanthus altissima (Mill. Swingle, indigo bush (Amorpha fruticosa L., Japanese knotweed (Reynoutria japonica Houtt. and giant goldenrod (Solidago gigantea Aiton. Three cultivated plant species from 3 different plant families were used as test-species. Test-species were: oat (Avena sativa L., oilseed rape (Brassica napus subsp. oleifera and sunflower (Helianthus annuus L.. Water extracts made of whole plants of donor species were applied to the seeds of the test-species. High allelopathic potential was proven for all species included in experiment. Allelopathic effects were exclusively negative. Impact on germination for all species was much lower in relation to the impact on the radicle and shoot length of the test-species. Perennial donor species had a stronger allelopathic potential than annual donor species. Tree of heaven was the species with the strongest allelopathic potential. Its extracts inhibited germination, radicle and shoot length of oilseed rape by 19%, 94.88% and 98.91% respectively.

  3. Plant–soil feedback induces shifts in biomass allocation in the invasive plant Chromolaena odorata

    CSIR Research Space (South Africa)

    Te Beest, M

    2009-09-01

    Full Text Available Soil communities and their interactions with plants may play a major role in determining the success of invasive species. However, rigorous investigations of this idea using cross-continental comparisons, including native and invasive plant...

  4. The distribution of a non-native (Rosa multiflora) and native (Kalmia latifolia) shrub in mature closed-canopy forests across soil fertility gradients

    Science.gov (United States)

    Cynthia D. Huebner; Jim Steinman; Todd F. Hutchinson; Todd E. Ristau; Alejandro A. Royo

    2014-01-01

    Background and aims. A soil fertility gradient, ranging from infertile to highly fertile soils, may define whether or not a plant will establish and spread at a site. We evaluated whether or not such a fertility gradient exists for Rosa multiflora Thunb., a nonnative invasive shrub, and Kalmia latifolia L., a...

  5. Invasive alien woody plants of the Orange Free State

    Directory of Open Access Journals (Sweden)

    L. Henderson

    1991-09-01

    Full Text Available The frequency and abundance of invasive alien woody plants were recorded along roadsides and at watercourse crossings in 66% (151/230 of the quarter degree squares in the study area. The survey yielded 64 species of which the most prominent (in order of prominence in streambank habitats were:  Salix babylonica, Populus x  canescens, Acacia dealbata and  Salix fragilis (fide R.D. Meikle pers. comm . The most prominent species (in order of prominence in roadside and veld habitats were:  Opunlia ficus-indica, Prunus persica, Eucalyptus spp..  Rosa eglanteria, Pyracantha angustifolia and Acacia dealbata.Little invasion was recorded for most of the province. The greatest intensity of invasion was recorded along the perennial rivers and rocky hillsides in the moist grassland of the eastern mountain region bordering on Lesotho and Natal.

  6. Novel weapons testing: are invasive plants more chemically defended than native plants?

    Directory of Open Access Journals (Sweden)

    Eric M Lind

    2010-05-01

    Full Text Available Exotic species have been hypothesized to successfully invade new habitats by virtue of possessing novel biochemistry that repels native enemies. Despite the pivotal long-term consequences of invasion for native food-webs, to date there are no experimental studies examining directly whether exotic plants are any more or less biochemically deterrent than native plants to native herbivores.In a direct test of this hypothesis using herbivore feeding assays with chemical extracts from 19 invasive plants and 21 co-occurring native plants, we show that invasive plant biochemistry is no more deterrent (on average to a native generalist herbivore than extracts from native plants. There was no relationship between extract deterrence and length of time since introduction, suggesting that time has not mitigated putative biochemical novelty. Moreover, the least deterrent plant extracts were from the most abundant species in the field, a pattern that held for both native and exotic plants. Analysis of chemical deterrence in context with morphological defenses and growth-related traits showed that native and exotic plants had similar trade-offs among traits.Overall, our results suggest that particular invasive species may possess deterrent secondary chemistry, but it does not appear to be a general pattern resulting from evolutionary mismatches between exotic plants and native herbivores. Thus, fundamentally similar processes may promote the ecological success of both native and exotic species.

  7. Fire and invasive exotic plant species in eastern oak communities: an assessment of current knowledge

    Science.gov (United States)

    Cynthia D. Huebner

    2006-01-01

    Successful regeneration of oak-dominated communities in the Eastern United States historically requires disturbance such as fire, making them vulnerable to invasion by exotic plants. Little is currently known about the effects of fire on invasive plant species and the effects of invasive plant species on fire regimes of this region. Seventeen common eastern invaders...

  8. Prescribed grazing for management of invasive vegetation in a hardwood forest understory

    Science.gov (United States)

    Ronald A. Rathfon; Songlin Fei; Jason Tower; Kenneth Andries; Michael. Neary

    2014-01-01

    Land managers considering prescribed grazing (PG) face a lack of information on animal stocking rates, timing of grazing, and duration of grazing to achieve desired conditions in natural ecosystems under invasion stress from a variety of nonnative invasive plant (NNIP) species. In this study we tested PG treatments using goats for reducing NNIP brush species and...

  9. Protected-area boundaries as filters of plant invasions

    Czech Academy of Sciences Publication Activity Database

    Foxcroft, L. C.; Jarošík, Vojtěch; Pyšek, Petr; Richardson, D. M.; Rouget, M.

    2010-01-01

    Roč. 25, č. 2 (2010), s. 400-405 ISSN 0888-8892 R&D Projects: GA MŠk LC06073; GA ČR GA206/09/0563 Grant - others: European Comission(XE) KBBE-212459 Institutional research plan: CEZ:AV0Z60050516 Keywords : protected areas * invasive plants * Kruger National Park Subject RIV: EF - Botanics Impact factor: 4.894, year: 2010

  10. Comparative patterns of plant invasions in the Mediterranean biome.

    Science.gov (United States)

    Arianoutsou, Margarita; Delipetrou, Pinelopi; Vilà, Montserrat; Dimitrakopoulos, Panayiotis G; Celesti-Grapow, Laura; Wardell-Johnson, Grant; Henderson, Lesley; Fuentes, Nicol; Ugarte-Mendes, Eduardo; Rundel, Philip W

    2013-01-01

    The objective of this work was to compare and contrast the patterns of alien plant invasions in the world's five mediterranean-climate regions (MCRs). We expected landscape age and disturbance history to have bearing on levels of invasion. We assembled a database on naturalized alien plant taxa occurring in natural and semi-natural terrestrial habitats of all five regions (specifically Spain, Italy, Greece and Cyprus from the Mediterranean Basin, California, central Chile, the Cape Region of South Africa and Southwestern - SW Australia). We used multivariate (hierarchical clustering and NMDS ordination) trait and habitat analysis to compare characteristics of regions, taxa and habitats across the mediterranean biome. Our database included 1627 naturalized species with an overall low taxonomic similarity among the five MCRs. Herbaceous perennials were the most frequent taxa, with SW Australia exhibiting both the highest numbers of naturalized species and the highest taxonomic similarity (homogenization) among habitats, and the Mediterranean Basin the lowest. Low stress and highly disturbed habitats had the highest frequency of invasion and homogenization in all regions, and high natural stress habitats the lowest, while taxonomic similarity was higher among different habitats in each region than among regions. Our analysis is the first to describe patterns of species characteristics and habitat vulnerability for a single biome. We have shown that a broad niche (i.e. more than one habitat) is typical of naturalized plant species, regardless of their geographical area of origin, leading to potential for high homogenization within each region. Habitats of the Mediterranean Basin are apparently the most resistant to plant invasion, possibly because their landscapes are generally of relatively recent origin, but with a more gradual exposure to human intervention over a longer period.

  11. Synergy between pathogen release and resource availability in plant invasion

    Czech Academy of Sciences Publication Activity Database

    Blumenthal, D.; Mitchell, C. E.; Pyšek, Petr; Jarošík, Vojtěch

    2009-01-01

    Roč. 106, č. 19 (2009), s. 7899-7904 ISSN 0027-8424 R&D Projects: GA MŠk LC06073 Grant - others:Evropská komise(XE) GOCE-CT-2003-506675 Institutional research plan: CEZ:AV0Z60050516 Keywords : plant invasions * enemy release * resource availability Subject RIV: EG - Zoology Impact factor: 9.432, year: 2009

  12. Plant invasion science in protected areas: progress and priorities

    Czech Academy of Sciences Publication Activity Database

    Foxcroft, L. C.; Pyšek, Petr; Richardson, D. M.; Genovesi, P.; MacFadyen, S.

    2017-01-01

    Roč. 19, č. 5 (2017), s. 1353-1378 ISSN 1387-3547 R&D Projects: GA ČR GB14-36079G Grant - others:AV ČR(CZ) AP1002 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985939 Keywords : plant invasions * global patterns * protected areas Subject RIV: EH - Ecology, Behaviour OBOR OECD: Biodiversity conservation Impact factor: 2.473, year: 2016

  13. Mycorrhizal status helps explain invasion success of alien plant species

    Czech Academy of Sciences Publication Activity Database

    Menzel, A.; Hempel, S.; Klotz, S.; Moora, M.; Pyšek, Petr; Rillig, M. C.; Zobel, M.; Kühn, I.

    2017-01-01

    Roč. 98, č. 1 (2017), s. 92-102 ISSN 0012-9658 R&D Projects: GA ČR GB14-36079G Grant - others:AV ČR(CZ) AP1002 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985939 Keywords : plant invasion * mycorrhiza * naturalization Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 4.809, year: 2016

  14. The long-tongued hawkmoth pollinator niche for native and invasive plants in Africa.

    Science.gov (United States)

    Johnson, Steven D; Raguso, Robert A

    2016-01-01

    Unrelated organisms that share similar niches often exhibit patterns of convergent evolution in functional traits. Based on bimodal distributions of hawkmoth tongue lengths and tubular white flowers in Africa, this study hypothesized that long-tongued hawkmoths comprise a pollination niche (ecological opportunity) that is distinct from that of shorter-tongued hawkmoths. Field observations, light trapping, camera surveillance and pollen load analysis were used to identify pollinators of plant species with very long-tubed (>8 cm) flowers. The nectar properties and spectral reflectance of these flowers were also measured. The frequency distributions of proboscis length for all captured hawkmoths and floral tube length for a representative sample of night-blooming plant species were determined. The geographical distributions of both native and introduced plant species with very long floral tubes were mapped. The convolvulus hawkmoth Agrius convolvuli is identified as the most important pollinator of African plants with very long-tubed flowers. Plants pollinated by this hawkmoth species tend to have a very long (approx. 10 cm) and narrow flower tube or spur, white flowers and large volumes of dilute nectar. It is estimated that >70 grassland and savanna plant species in Africa belong to the Agrius pollination guild. In South Africa, at least 23 native species have very long floral tubes, and pollination by A. convolvuli or, rarely, by the closely related hawkmoth Coelonia fulvinotata, has been confirmed for 11 of these species. The guild is strikingly absent from the species-rich Cape floral region and now includes at least four non-native invasive species with long-tubed flowers that are pre-adapted for pollination by A. convolvuli. This study highlights the value of a niche perspective on pollination, which provides a framework for making predictions about the ecological importance of keystone pollinators, and for understanding patterns of convergent evolution and

  15. Interactions among invasive plants: Lessons from Hawai‘i

    Science.gov (United States)

    D'Antonio, Carla M.; Ostertag, Rebecca; Cordell, Susan; Yelenik, Stephanie G.

    2017-01-01

    Most ecosystems have multiple-plant invaders rather than single-plant invaders, yet ecological studies and management actions focus largely on single invader species. There is a need for general principles regarding invader interactions across varying environmental conditions, so that secondary invasions can be anticipated and managers can allocate resources toward pretreatment or postremoval actions. By reviewing removal experiments conducted in three Hawaiian ecosystems (a dry tropical forest, a seasonally dry mesic forest, and a lowland wet forest), we evaluate the roles environmental harshness, priority effects, productivity potential, and species interactions have in influencing secondary invasions, defined here as invasions that are influenced either positively (facilitation) or negatively (inhibition/priority effects) by existing invaders. We generate a conceptual model with a surprise index to describe whether long-term plant invader composition and dominance is predictable or stochastic after a system perturbation such as a removal experiment. Under extremely low resource availability, the surprise index is low, whereas under intermediate-level resource environments, invader dominance is more stochastic and the surprise index is high. At high resource levels, the surprise index is intermediate: Invaders are likely abundant in the environment but their response to a perturbation is more predictable than at intermediate resource levels. We suggest further testing across environmental gradients to determine key variables that dictate the predictability of postremoval invader composition.

  16. Floristic characteristics of alien invasive seed plant species in China.

    Science.gov (United States)

    Wang, Congyan; Liu, Jun; Xiao, Hongguang; Zhou, Jiawei; DU, Daolin

    2016-01-01

    This study aims to determine the floristic characteristics of alien invasive seed plant species (AISPS) in China. There are a total of five hundred and thirteen AISPS, belonging to seventy families and two hundred and eighty-three genera. Seventy families were classified into nine areal types at the family level, and "Cosmopolitan" and "Pantropic" are the two main types. Two hundred and eighty-three genera were classified into twelve areal types at the genus level, and "Pantropic", "Trop. Asia & Amer. disjuncted", and "Cosmopolitan" are the three main types. These results reveal a certain degree of diversity among AISPS in China. The floristic characteristics at the family level exhibit strong pantropic characteristics. Two possible reasons for this are as follows. Firstly, southeastern China is heavily invaded by alien invasive plant species and this region has a mild climate. Secondly, southeastern China is more disturbed by human activities than other regions in China. The floristic characteristics at the genus level display strong pantropic but with abundant temperate characteristics. This may be due to that China across five climatic zones and the ecosystems in which the most alien invasive plant species occur have the same or similar climate with their natural habitat.

  17. Invasive alien woody plants of the northern Cape

    Directory of Open Access Journals (Sweden)

    L. Henderson

    1991-10-01

    Full Text Available The frequency and abundance of invasive alien woody plants were recorded along roadsides and at watercourse crossings in 31% (90/286 of the quarter degree squares in the study area. The survey yielded 23 species of which the most prominent invaders were Prosopis spp. The most prominent remaining species were: Opuntia ficus-indica, Nicotiana glauca and Melia azedarach. The greatest abundance and diversity of alien invader plants were recorded near human settlements. More than half of the total recorded species have invaded perennial riverbanks. The episodic Molopo and Kuruman Rivers have been invaded almost exclusively by  Prosopis spp., which in places have formed extensive stands.

  18. Invasive vascular plant species of limnocrenic karst springs in Poland

    Science.gov (United States)

    Spałek, Krzysztof

    2015-04-01

    Natural water reservoirs are very valuable floristic sites in Poland. Among them, the most important for preservation of biodiversity of flora are limnocrenic karst springs. The long-term process of human pressure on habitats of this type caused disturbance of their biological balance. Changes in the water regime, industrial development and chemisation of agriculture, especially in the period of last two hundred years, led to systematic disappearance of localities of many plant species connected with rare habitats and also to appear numerous invasive plant species. They are: Acorus calamus, Echinocystis lobata, Elodea canadensis, Erechtites hieraciifolia, Impatiens glandulifera, Solidago canadensis, S. gigantea and S. graminifolia. Fielworks were conducted in 2010-2014.

  19. Biological Invasion Influences the Outcome of Plant-Soil Feedback in the Invasive Plant Species from the Brazilian Semi-arid.

    Science.gov (United States)

    de Souza, Tancredo Augusto Feitosa; de Andrade, Leonaldo Alves; Freitas, Helena; da Silva Sandim, Aline

    2017-05-30

    Plant-soil feedback is recognized as the mutual interaction between plants and soil microorganisms, but its role on the biological invasion of the Brazilian tropical seasonal dry forest by invasive plants still remains unclear. Here, we analyzed and compared the arbuscular mycorrhizal fungi (AMF) communities and soil characteristics from the root zone of invasive and native plants, and tested how these AMF communities affect the development of four invasive plant species (Cryptostegia madagascariensis, Parkinsonia aculeata, Prosopis juliflora, and Sesbania virgata). Our field sampling revealed that AMF diversity and frequency of the Order Diversisporales were positively correlated with the root zone of the native plants, whereas AMF dominance and frequency of the Order Glomerales were positively correlated with the root zone of invasive plants. We grew the invasive plants in soil inoculated with AMF species from the root zone of invasive (I changed ) and native (I unaltered ) plant species. We also performed a third treatment with sterilized soil inoculum (control). We examined the effects of these three AMF inoculums on plant dry biomass, root colonization, plant phosphorous concentration, and plant responsiveness to mycorrhizas. We found that I unaltered and I changed promoted the growth of all invasive plants and led to a higher plant dry biomass, mycorrhizal colonization, and P uptake than control, but I changed showed better results on these variables than I unaltered . For plant responsiveness to mycorrhizas and fungal inoculum effect on plant P concentration, we found positive feedback between changed-AMF community (I changed ) and three of the studied invasive plants: C. madagascariensis, P. aculeata, and S. virgata.

  20. Woody invasions of urban trails and the changing face of urban forests in the great plains, USA

    Science.gov (United States)

    Nemec, K.T.; Allen, Craig R.; Alai, A.; Clements, G.; Kessler, A.C.; Kinsell, T.; Major, A.; Stephen, B.J.

    2011-01-01

    Corridors such as roads and trails can facilitate invasions by non-native plant species. The open, disturbed habitat associated with corridors provides favorable growing conditions for many non-native plant species. Bike trails are a corridor system common to many urban areas that have not been studied for their potential role in plant invasions. We sampled five linear segments of urban forest along bike trails in Lincoln, Nebraska to assess the invasion of woody non-native species relative to corridors and to assess the composition of these urban forests. The most abundant plant species were generally native species, but five non-native species were also present: white mulberry (Morus alba), common buckthorn (Rhamnus cathartica), tree-of-heaven (Ailanthus altissima), honeysuckle (Lonicera spp.) and elm (Ulmus spp.). The distribution of two of the woody species sampled, common buckthorn and honeysuckle, significantly decreased with increasing distance from a source patch of vegetation (P = 0.031 and 0.030). These linear habitats are being invaded by non-native tree and shrub species, which may change the structure of these urban forest corridors. If non-native woody plant species become abundant in the future, they may homogenize the plant community and reduce native biodiversity in these areas. ?? 2011 American Midland Naturalist.

  1. The Development of a Plant Risk Evaluation (PRE) Tool for Assessing the Invasive Potential of Ornamental Plants

    OpenAIRE

    Conser, Christiana; Seebacher, Lizbeth; Fujino, David W.; Reichard, Sarah; DiTomaso, Joseph M.

    2015-01-01

    Weed Risk Assessment (WRA) methods for evaluating invasiveness in plants have evolved rapidly in the last two decades. Many WRA tools exist, but none were specifically designed to screen ornamental plants prior to being released into the environment. To be accepted as a tool to evaluate ornamental plants for the nursery industry, it is critical that a WRA tool accurately predicts non-invasiveness without falsely categorizing them as invasive. We developed a new Plant Risk Evaluation (PRE) too...

  2. Belowground legacies of Pinus contorta invasion and removal result in multiple mechanisms of invasional meltdown.

    Science.gov (United States)

    Dickie, Ian A; St John, Mark G; Yeates, Gregor W; Morse, Chris W; Bonner, Karen I; Orwin, Kate; Peltzer, Duane A

    2014-01-01

    Plant invasions can change soil biota and nutrients in ways that drive subsequent plant communities, particularly when co-invading with belowground mutualists such as ectomycorrhizal fungi. These effects can persist following removal of the invasive plant and, combined with effects of removal per se, influence subsequent plant communities and ecosystem functioning. We used field observations and a soil bioassay with multiple plant species to determine the belowground effects and post-removal legacy caused by invasion of the non-native tree Pinus contorta into a native plant community. Pinus facilitated ectomycorrhizal infection of the co-occurring invasive tree, Pseudotsuga menziesii, but not conspecific Pinus (which always had ectomycorrhizas) nor the native pioneer Kunzea ericoides (which never had ectomycorrhizas). Pinus also caused a major shift in soil nutrient cycling as indicated by increased bacterial dominance, NO3-N (17-fold increase) and available phosphorus (3.2-fold increase) in soils, which in turn promoted increased growth of graminoids. These results parallel field observations, where Pinus removal is associated with invasion by non-native grasses and herbs, and suggest that legacies of Pinus on soil nutrient cycling thus indirectly promote invasion of other non-native plant species. Our findings demonstrate that multi-trophic belowground legacies are an important but hitherto largely unconsidered factor in plant community reassembly following invasive plant removal. Published by Oxford University Press on behalf of the Annals of Botany Company.

  3. Invasive plants as feedstock for biochar and bioenergy production.

    Science.gov (United States)

    Liao, Rui; Gao, Bin; Fang, June

    2013-07-01

    In this work, the potential of invasive plant species as feedstock for value-added products (biochar and bioenergy) through pyrolysis was investigated. The product yield rates of two major invasive species in the US, Brazilian Pepper (BP) and Air Potato (AP), were compared to that of two traditional feedstock materials, water oak and energy cane. Three pyrolysis temperatures (300, 450, and 600°C) and four feedstock masses (10, 15, 20, and 25 g) were tested for a total of 12 experimental conditions. AP had high biochar and low oil yields, while BP had a high oil yield. At lower temperatures, the minimum feedstock residence time for biochar and bioenergy production increased at a faster rate as feedstock weight increased than it did at higher temperatures. A simple mathematical model was successfully developed to describe the relationship between feedstock weight and the minimum residence time. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Litter drives ecosystem and plant community changes in cattail invasion.

    Science.gov (United States)

    Farrer, Emily C; Goldberg, Deborah E

    2009-03-01

    Invaded systems are commonly associated with a change in ecosystem processes and a decline in native species diversity; however, many different causal pathways linking invasion, ecosystem change, and native species decline could produce this pattern. The initial driver of environmental change may be anthropogenic, or it may be the invader itself; and the mechanism behind native species decline may be the human-induced environmental change, competition from the invader, or invader-induced environmental change (non-trophic effects). We examined applicability of each of these alternate pathways in Great Lakes coastal marshes invaded by hybrid cattail (Typha x glauca). In a survey including transects in three marshes, we found that T. x glauca was associated with locally high soil nutrients, low light, and large amounts of litter, and that native diversity was highest in areas of shallow litter depth. We tested whether live T. x glauca plants or their litter induced changes in the environment and in diversity with a live plant and litter transplant experiment. After one year, Typha litter increased soil NH4+ and N mineralization twofold, lowered light levels, and decreased the abundance and diversity of native plants, while live Typha plants had no effect on the environment or on native plants. This suggests that T. x glauca, through its litter production, can cause the changes in ecosystem processes that we commonly attribute to anthropogenic nutrient loading and that T. x glauca does not displace native species through competition for resources, but rather affects them non-trophically through its litter. Moreover, because T. x glauca plants were taller when grown with their own litter, we suggest that this invader may produce positive feedbacks and change the environment in ways that benefit itself and may promote its own invasion.

  5. Characterizing the Status (Disturbed, Hybrid or Novel) of Swamp Forest Fragments in a Caribbean Ramsar Wetland: The Impact of Anthropogenic Degradation and Invasive Plant Species.

    Science.gov (United States)

    Prospere, Kurt; McLaren, Kurt P; Wilson, Byron

    2016-10-01

    The last remaining Amazonian-type swamp forest fragments in Black River Lower Morass, Jamaica, have been subjected to a myriad of anthropogenic disturbances, compounded by the establishment and spread of several invasive plant species. We established 44 permanent sample plots (covering 3.92 ha) across 10 of these swamp forest fragments and sampled all non-woody plants and all trees ≥2 cm DBH found in the plots. These data were used to (1) identify thresholds of hybridity and novelty, (2) derive several diversity and structural descriptors used to characterize the swamp forest fragments and (3) identify possible indicators of anthropogenic degradation. These were incorporated into a framework and used to determine the status of the swamp forest fragments so that appropriate management and conservation measures can be implemented. We recorded 43 woody plant species (9 endemic, 28 native and 4 non-native) and 21 non-tree species. The composition and structure of all the patches differed significantly due to the impact of the herbaceous invasive plant Alpinia allughas, the presence and diversity of other non-native plants, and differing intensities of anthropogenic disturbance (e.g., burning, cutting and harvesting of non-timber forest products). We ranked forest patches along a continuum representing deviations from a historical proxy (least disturbed) swamp forest to those with dramatically altered structural and floristic attributes (=novel swamp forests). Only one fragment overrun with A. allughas was classified as novel. If effective conservation and management does not come to the BRLM, the remaining swamp forest fragments appear doomed to further degradation and will soon disappear altogether.

  6. Self-reinforcing impacts of plant invasions change over time.

    Science.gov (United States)

    Yelenik, Stephanie G; D'Antonio, Carla M

    2013-11-28

    Returning native species to habitats degraded by biological invasions is a critical conservation goal. A leading hypothesis poses that exotic plant dominance is self-reinforced by impacts on ecosystem processes, leading to persistent stable states. Invaders have been documented to modify fire regimes, alter soil nutrients or shift microbial communities in ways that feed back to benefit themselves over competitors. However, few studies have followed invasions through time to ask whether ecosystem impacts and feedbacks persist. Here we return to woodland sites in Hawai'i Volcanoes National Park that were invaded by exotic C4 grasses in the 1960s, the ecosystem impacts of which were studied intensively in the 1990s. We show that positive feedbacks between exotic grasses and soil nitrogen cycling have broken down, but rather than facilitating native vegetation, the weakening feedbacks facilitate new exotic species. Data from the 1990s showed that exotic grasses increased nitrogen-mineralization rates by two- to fourfold, but were nitrogen-limited. Thus, the impacts of the invader created a positive feedback early in the invasion. We now show that annual net soil nitrogen mineralization has since dropped to pre-invasion levels. In addition, a seedling outplanting experiment that varied soil nitrogen and grass competition demonstrates that the changing impacts of grasses do not favour native species re-establishment. Instead, decreased nitrogen availability most benefits another aggressive invader, the nitrogen-fixing tree Morella faya. Long-term studies of invasions may reveal that ecosystem impacts and feedbacks shift over time, but that this may not benefit native species recovery.

  7. Public reaction to invasive plant species in a disturbed Colorado landscape

    Science.gov (United States)

    Michael T. Daab; Courtney G. Flint

    2010-01-01

    Invasive plant species degrade ecosystems in many ways. Controlling invasive plants is costly for government agencies, businesses, and individuals. North central Colorado is currently experiencing large-scale disturbance, and millions of acres are vulnerable to invasion because of natural and socioeconomic processes. Mountain pine beetles typically endemic to this...

  8. Exotic plant invasions in successional systems: the utility of a long-term approach

    Science.gov (United States)

    Scott J. Meiners; Mary L. Cadenasso; Steward T. A. Pickett

    2003-01-01

    The limited temporal duration of most studies constrains our understanding of the dynamics of invasion, and the subsequent function of exotic species in plant communities. While most plant invasions occur over time periods of decades or longer, most experimental studies of invasions are brief, lasting only 1-2 years.

  9. Differential population responses of native and alien rodents to an invasive predator, habitat alteration and plant masting.

    Science.gov (United States)

    Fukasawa, Keita; Miyashita, Tadashi; Hashimoto, Takuma; Tatara, Masaya; Abe, Shintaro

    2013-12-22

    Invasive species and anthropogenic habitat alteration are major drivers of biodiversity loss. When multiple invasive species occupy different trophic levels, removing an invasive predator might cause unexpected outcomes owing to complex interactions among native and non-native prey. Moreover, external factors such as habitat alteration and resource availability can affect such dynamics. We hypothesized that native and non-native prey respond differently to an invasive predator, habitat alteration and bottom-up effects. To test the hypothesis, we used Bayesian state-space modelling to analyse 8-year data on the spatio-temporal patterns of two endemic rat species and the non-native black rat in response to the continual removal of the invasive small Indian mongoose on Amami Island, Japan. Despite low reproductive potentials, the endemic rats recovered better after mongoose removal than did the black rat. The endemic species appeared to be vulnerable to predation by mongooses, whose eradication increased the abundances of the endemic rats, but not of the black rat. Habitat alteration increased the black rat's carrying capacity, but decreased those of the endemic species. We propose that spatio-temporal monitoring data from eradication programmes will clarify the underlying ecological impacts of land-use change and invasive species, and will be useful for future habitat management.

  10. Modeling invasive alien plant species in river systems : Interaction with native ecosystem engineers and effects on hydro-morphodynamic processes

    NARCIS (Netherlands)

    van Oorschot, M.; Kleinhans, M. G.; Geerling, G.W.; Egger, G.; Leuven, R.S.E.W.; Middelkoop, H.

    2017-01-01

    Invasive alien plant species negatively impact native plant communities by out-competing species or changing abiotic and biotic conditions in their introduced range. River systems are especially vulnerable to biological invasions, because waterways can function as invasion corridors. Understanding

  11. Short-Term Response of Native Flora to the Removal of Non-Native Shrubs in Mixed-Hardwood Forests of Indiana, USA

    Directory of Open Access Journals (Sweden)

    Joshua M. Shields

    2015-05-01

    Full Text Available While negative impacts of invasive species on native communities are well documented, less is known about how these communities respond to the removal of established populations of invasive species. With regard to invasive shrubs, studies examining native community response to removal at scales greater than experimental plots are lacking. We examined short-term effects of removing Lonicera maackii (Amur honeysuckle and other non-native shrubs on native plant taxa in six mixed-hardwood forests. Each study site contained two 0.64 ha sample areas—an area where all non-native shrubs were removed and a reference area where no treatment was implemented. We sampled vegetation in the spring and summer before and after non-native shrubs were removed. Cover and diversity of native species, and densities of native woody seedlings, increased after shrub removal. However, we also observed significant increases in L. maackii seedling densities and Alliaria petiolata (garlic mustard cover in removal areas. Changes in reference areas were less pronounced and mostly non-significant. Our results suggest that removing non-native shrubs allows short-term recovery of native communities across a range of invasion intensities. However, successful restoration will likely depend on renewed competition with invasive species that re-colonize treatment areas, the influence of herbivores, and subsequent control efforts.

  12. Foraging Behavior Interactions Between Two non-Native Social Wasps, Vespula germanica and V. vulgaris (Hymenoptera: Vespidae): Implications for Invasion Success?

    OpenAIRE

    Pereira, Ana Julia; Pirk, Gabriela I.; Corley, Juan C.

    2016-01-01

    Vespula vulgaris is an invasive scavenging social wasp that has very recently arrived in Patagonia (Argentina), a territory previously invaded ? 35 yrs earlier ? by another wasp, Vespula germanica. Although V. vulgaris wasps possess features that could be instrumental in overcoming obstacles through several invasion stages, the presence of preestablished populations of V. germanica could affect their success. We studied the potential role played by V. germanica on the subsequent invasion proc...

  13. Effects of an invasive plant species, celastrus orbiculatus, on soil composition and processes

    Science.gov (United States)

    Leicht-Young, S. A.; O'Donnell, H.; Latimer, A.M.; Silander, J.A.

    2009-01-01

    Celastrus orbiculatus is a non-native, invasive liana that was introduced to the United States in the 1860s and has spread rapidly throughout the Northeast Several attributes contribute to the invasiveness of C. orbiculatus, including tolerance to a wide range of light levels and habitat types. We compared soil characteristics in seven sets of adjacent, paired plots, spanning a range of habitats and soil types, with and without C. orbiculatus. The paired plots were similar other than the presence or absence of Celastrus. Plots with C. orbiculatus had significantly higher soil pH, potassium, calcium and magnesium levels. Furthermore, nitrogen mineralization and litter decomposition rates were higher in plots with C. orbiculatus. Phosphorus levels were not significantly different between the paired plots. The results of this study contribute to the growing body of research of the effects of invasive species on ecosystem processes.

  14. Invasiveness does not predict impact: response of native land snail communities to plant invasions in riparian habitats

    Czech Academy of Sciences Publication Activity Database

    Horáčková, J.; Juřičková, L.; Šizling, A. L.; Jarošík, Vojtěch; Pyšek, Petr

    2014-01-01

    Roč. 9, č. 9 (2014), s. 1-10, e108296 E-ISSN 1932-6203 Institutional support: RVO:67985939 Keywords : plant invasions * land snails * impact Subject RIV: EF - Botanics Impact factor: 3.234, year: 2014

  15. Invasive plant species: Inventory, mapping, and monitoring - A national strategy

    Science.gov (United States)

    Ludke, J. Larry; D'Erchia, Frank; Coffelt, Jan; Hanson, Leanne

    2002-01-01

    America is under siege by invasive species of plants and animals, and by diseases. The current environmental, economic, and health-related costs of invasive species could exceed $138 billion per year-more than all other natural disasters combined. Notorious examples include West Nile virus, Dutch elm disease, chestnut blight, and purple loose- strife in the Northeast; kudzu, Brazilian peppertree, water hyacinth, nutria, and fire ants in the Southeast; zebra mussels, leafy spurge, and Asian long-horn beetles in the Midwest; salt cedar, Russian olive, and Africanized bees in the Southwest; yellow star thistle, European wild oats, oak wilt disease, Asian clams, and white pine blister rust in California; cheatgrass, various knapweeds, and thistles in the Great Basin; whirling disease of salmonids in the Northwest; hundreds of invasive species from microbes to mammals in Hawaii; and the brown tree snake in Guam. Thousands of species from other countries are introduced intentionally or accidentally into the United States each year. Based on past experience, 10-15 percent can be expected to establish free-living populations and about 1 percent can be expected to cause significant impacts to ecosystems, native species, economic productivity, and (or) human health.

  16. 78 FR 46889 - Endangered and Threatened Wildlife and Plants; 12-Month Finding and Candidate Removal for...

    Science.gov (United States)

    2013-08-02

    ... Removal for Potentilla basaltica; Proposed Threatened Species Status for Ivesia webberi AGENCY: Fish and..., invasive plant species--have been substantially reduced since 2002. The BLM implemented several measures... respond to nonnative, invasive plant species using chemical control and other treatment methods (Service...

  17. Do native parasitic plants cause more damage to exotic invasive hosts than native non-invasive hosts? An implication for biocontrol.

    Science.gov (United States)

    Li, Junmin; Jin, Zexin; Song, Wenjing

    2012-01-01

    Field studies have shown that native, parasitic plants grow vigorously on invasive plants and can cause more damage to invasive plants than native plants. However, no empirical test has been conducted and the mechanism is still unknown. We conducted a completely randomized greenhouse experiment using 3 congeneric pairs of exotic, invasive and native, non-invasive herbaceous plant species to quantify the damage caused by parasitic plants to hosts and its correlation with the hosts' growth rate and resource use efficiency. The biomass of the parasitic plants on exotic, invasive hosts was significantly higher than on congeneric native, non-invasive hosts. Parasites caused more damage to exotic, invasive hosts than to congeneric, native, non-invasive hosts. The damage caused by parasites to hosts was significantly positively correlated with the biomass of parasitic plants. The damage of parasites to hosts was significantly positively correlated with the relative growth rate and the resource use efficiency of its host plants. It may be the mechanism by which parasitic plants grow more vigorously on invasive hosts and cause more damage to exotic, invasive hosts than to native, non-invasive hosts. These results suggest a potential biological control effect of native, parasitic plants on invasive species by reducing the dominance of invasive species in the invaded community.

  18. Invasive Plants Field and Reference Guide: An Ecological Perspective of Plant Invaders of Forests and Woodlands

    Science.gov (United States)

    Cynthia D. Huebner; Cassandra Olson; Heather C. Smith; Heather C. Smith

    2005-01-01

    There are many field guides available about invasive plants and their identification. The purpose of this particular field guide is to give a scientific synthesis of what is known about the behavior of such species in managed, disturbed, and pristine forested systems in addition to key information for accurate identification.

  19. Insect herbivory stimulates allelopathic exudation by an invasive plant and the suppression of natives

    Science.gov (United States)

    Giles C. Thelen; Jorge M. Vivanco; Beth Newingham; William Good; Harsh P. Bais; Peter Landres; Anthony Caesar; Ragan M. Callaway

    2005-01-01

    Exotic invasive plants are often subjected to attack from imported insects as a method of biological control. A fundamental, but rarely explicitly tested, assumption of biological control is that damaged plants are less fit and compete poorly. In contrast, we find that one of the most destructive invasive plants in North America, Centaurea maculosa,...

  20. Climate effects caused by land plant invasion in the Devonian

    Science.gov (United States)

    Hir guillaume, Le; yannick, Donnadieu; yves, Goddéris; brigitte, Meyer-Berthaud; gilles, Ramstein

    2017-04-01

    Land plants invaded continents during the Mid-Paleozoic. Their spreading and diversification have been compared to the Cambrian explosion in terms of intensity and impact on the diversification of life on Earth. Whereas prior studies were focused on the evolution of the root system and its weathering contribution, here we investigated the biophysical impacts of plant colonization on the surface climate through changes in continental albedo, roughness, thermal properties, and potential evaporation using a 3D-climate model coupled to a global biogeochemical cycles associated to a simple model for vegetation dynamics adapted to Devonian conditions. From the Early to the Late Devonian, we show that continental surface changes induced by land plants and tectonic drift have produced a large CO2 drawdown without being associated to a global cooling, because the cooling trend is counteracted by a warming trend resulting from the surface albedo reduction. If CO2 is consensually assumed as the main driver of the Phanerozoic climate, during land-plant invasion, the modifications of soil properties could have played in the opposite direction of the carbon dioxide fall, hence maintaining warm temperatures during part of the Devonian.

  1. Impacts of invasive alien plants on water quality, with particular emphasis on South Africa

    OpenAIRE

    Chamier, J; Schachtschneider, K; le Maitre, DC; Ashton, PJ; van Wilgen, BW

    2012-01-01

    We review the current state of knowledge of quantified impacts of invasive alien plants on water quality, with a focus on South Africa. In South Africa, over 200 introduced plant species are regarded as invasive. Many of these species are particularly prominent in riparian ecosystems and their spread results in native species loss, increased biomass and fire intensity and consequent erosion, as well as decreased river flows. Research on the impact of invasive alien plants on water resources h...

  2. Enhanced shoot investment makes invasive plants exhibit growth advantages in high nitrogen conditions.

    Science.gov (United States)

    Liu, X A; Peng, Y; Li, J J; Peng, P H

    2018-03-12

    Resource amendments commonly promote plant invasions, raising concerns over the potential consequences of nitrogen (N) deposition; however, it is unclear whether invaders will benefit from N deposition more than natives. Growth is among the most fundamental inherent traits of plants and thus good invaders may have superior growth advantages in response to resource amendments. We compared the growth and allocation between invasive and native plants in different N regimes including controls (ambient N concentrations). We found that invasive plants always grew much larger than native plants in varying N conditions, regardless of growth- or phylogeny-based analyses, and that the former allocated more biomass to shoots than the latter. Although N addition enhanced the growth of invasive plants, this enhancement did not increase with increasing N addition. Across invasive and native species, changes in shoot biomass allocation were positively correlated with changes in whole-plant biomass; and the slope of this relationship was greater in invasive plants than native plants. These findings suggest that enhanced shoot investment makes invasive plants retain a growth advantage in high N conditions relative to natives, and also highlight that future N deposition may increase the risks of plant invasions.

  3. Intraspecific plant-soil feedback as a mechanism underlying invasiveness of neophytes of the Czech Republic

    OpenAIRE

    Knobová, Pavlína

    2017-01-01

    Intraspecific plant-soil feedback is a relationship in which plant affects the composition of the soil and such modified soil affects growth of the same plant species. This relationship and its intensity may be linked with plant dominance and invasiveness. Dominant species can alter the composition of the soil in their favor and thus show positive intraspecific plant-soil feedback. As the invasive species are commonly being dominant in their new environment, it can be expected that intraspeci...

  4. What determines positive, neutral, and negative impacts of Solidago canadensis invasion on native plant species richness?

    Science.gov (United States)

    Dong, Li-Jia; Yu, Hong-Wei; He, Wei-Ming

    2015-11-17

    Whether plant invasions pose a great threat to native plant diversity is still hotly debated due to conflicting findings. More importantly, we know little about the mechanisms of invasion impacts on native plant richness. We examined how Solidago canadensis invasion influenced native plants using data from 291 pairs of invaded and uninvaded plots covering an entire invaded range, and quantified the relative contributions of climate, recipient communities, and S. canadensis to invasion impacts. There were three types of invasion consequences for native plant species richness (i.e., positive, neutral, and negative impacts). Overall, the relative contributions of recipient communities, S. canadensis and climate to invasion impacts were 71.39%, 21.46% and 7.15%, respectively; furthermore, the roles of recipient communities, S. canadensis and climate were largely ascribed to plant diversity, density and cover, and precipitation. In terms of direct effects, invasion impacts were negatively linked to temperature and native plant communities, and positively to precipitation and soil microbes. Soil microbes were crucial in the network of indirect effects on invasion impacts. These findings suggest that the characteristics of recipient communities are the most important determinants of invasion impacts and that invasion impacts may be a continuum across an entire invaded range.

  5. Phytophagous insect fauna tracks host plant responses to exotic grass invasion.

    Science.gov (United States)

    Almeida-Neto, Mário; Prado, Paulo I; Lewinsohn, Thomas M

    2011-04-01

    The high dependence of herbivorous insects on their host plants implies that plant invaders can affect these insects directly, by not providing a suitable habitat, or indirectly, by altering host plant availability. In this study, we sampled Asteraceae flower heads in cerrado remnants with varying levels of exotic grass invasion to evaluate whether invasive grasses have a direct effect on herbivore richness independent of the current disturbance level and host plant richness. By classifying herbivores according to the degree of host plant specialization, we also investigated whether invasive grasses reduce the uniqueness of the herbivorous assemblages. Herbivorous insect richness showed a unimodal relationship with invasive grass cover that was significantly explained only by way of the variation in host plant richness. The same result was found for polyphagous and oligophagous insects, but monophages showed a significant negative response to the intensity of the grass invasion that was independent of host plant richness. Our findings lend support to the hypothesis that the aggregate effect of invasive plants on herbivores tends to mirror the effects of invasive plants on host plants. In addition, exotic plants affect specialist insects differently from generalist insects; thus exotic plants affect not only the size but also the structural profile of herbivorous insect assemblages.

  6. Perceptions of impact: Invasive alien plants in the urban environment.

    Science.gov (United States)

    Potgieter, Luke J; Gaertner, Mirijam; O'Farrell, Patrick J; Richardson, David M

    2018-06-08

    Many alien plant species are introduced to urban areas to create, augment or restore ecosystem services (ES). However, many of these species spread beyond original plantings, sometimes causing negative effects on existing ES or creating novel ecosystem disservices (EDS). An understanding of the perceptions of urban residents regarding invasive alien plants (IAPs) and the ES and EDS they provide is needed for the effective prioritisation of IAP management efforts in cities. Using the city of Cape Town, South Africa as a case study, we conducted questionnaire-based surveys (online and face-to-face) to determine the perceptions of urban residents regarding IAPs and their capacity to provide ES and EDS. Most urban residents perceive IAPs negatively (i.e. agreeing that they create EDS), but many recognise their importance in providing ES. Although most residents are not opposed to the management of IAPs, such actions are not perceived as a high priority relative to other environmental problems. Socio-demographic variables such as age, education, environmental awareness, and ethnicity shape urban residents' perceptions of IAPs. Older, more educated respondents were more likely to perceive IAPs negatively, while respondents with greater environmental awareness were aware of the benefits provided by IAPs. This study highlights the need to integrate public perceptions into the planning and management of IAPs and emphasises the importance of including ES assessments into the decision-making process, particularly in urban areas. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. [Allelopathic effects of invasive weed Solidago canadensis on native plants].

    Science.gov (United States)

    Mei, Lingxiao; Chen, Xin; Tang, Jianjun

    2005-12-01

    With growth chamber method, this paper studied the allelopathic potential of invasive weed Solidago canadensis on native plant species. Different concentration S. canadensis root and rhizome extracts were examined, and the test plants were Trifolium repens, Trifolium pretense, Medicago lupulina, Lolium perenne, Suaeda glauca, Plantago virginica, Kummerowia stipulacea, Festuca arundinacea, Ageratum conyzoides, Portulaca oleracea, and Amaranthus spinosus. The results showed that the allelopathic inhibitory effect of the extracts from both S. canadensis root and rhizome was enhanced with increasing concentration, and rhizome extracts had a higher effect than root extracts. At the lowest concentration (1:60), root extract had little effect on the seed germination and seedling growth of T. repens, but rhizome extract could inhibit the germination of all test plants though the inhibitory effect varied with different species. The inhibition was the greatest for grass, followed by forb and legume. 1:60 (m:m) rhizome extract had similar effects on seed germination and radicel growth, but for outgrowth, the extract could inhibit Kummerowia stipulacea, Amaranthus spinosus and Festuca arundinacea, had no significant impact on Lolium perenne, Plantago virginica, Ageratum conyzoides, Portulaca oleracea and Amaranthus spinosus, and stimulated Trifolium repens, Trifolium pretense and Medicago lupulina.

  8. Plant-associated bacterial populations on native and invasive plant species: comparisons between 2 freshwater environments.

    Science.gov (United States)

    Olapade, Ola A; Pung, Kayleigh

    2012-06-01

    Plant-microbial interactions have been well studied because of the ecological importance of such relationships in aquatic systems. However, general knowledge regarding the composition of these biofilm communities is still evolving, partly as a result of several confounding factors that are attributable to plant host properties and to hydrodynamic conditions in aquatic environments. In this study, the occurrences of various bacterial phylogenetic taxa on 2 native plants, i.e., mayapple (Podophyllum peltatum L.) and cow parsnip (Heracleum maximum Bartram), and on an invasive species, i.e., garlic mustard (Alliaria petiolata (M. Bieb.) Cavara & Grande), were quantitatively examined using nucleic acid staining and fluorescence in situ hybridization. The plants were incubated in triplicates for about a week within the Kalamazoo River and Pierce Cedar Creek as well as in microcosms. The bacterial groups targeted for enumeration are known to globally occur in relatively high abundance and are also ubiquitously distributed in freshwater environments. Fluorescence in situ hybridization analyses of the bacterioplankton assemblages revealed that the majority of bacterial cells that hybridized with the different probes were similar between the 2 sites. In contrast, the plant-associated populations while similar on the 3 plants incubated in Kalamazoo River, their representations were highest on the 2 native plants relative to the invasive species in Pierce Cedar Creek. Overall, our results further suggested that epiphytic bacterial assemblages are probably under the influences of and probably subsequently respond to multiple variables and conditions in aquatic milieus.

  9. Climate suitability and human influences combined explain the range expansion of an invasive horticultural plant

    Science.gov (United States)

    Carolyn M. Beans; Francis F. Kilkenny; Laura F. Galloway

    2012-01-01

    Ecological niche models are commonly used to identify regions at risk of species invasions. Relying on climate alone may limit a model's success when additional variables contribute to invasion. While a climate-based model may predict the future spread of an invasive plant, we hypothesized that a model that combined climate with human influences would most...

  10. Patterns of alien plant invasion across coastal bay areas in southern China

    Science.gov (United States)

    Hai Ren; Qinfeng Guo; Hong Liu; Jing Li; Qianmei Zhang; Hualin Xu; Fanghong Xu

    2014-01-01

    An understanding of the ways in which levels of invasions by alien species are correlated with environmental factors is helpful to manage the negative impacts of these invasive species. Two tropical coastal areas in South China, Shenzhen Bay and Leizhou Bay, are national nature reserves, but they are threatened by invasive plants. Here, we investigated the level of...

  11. Aliens in Transylvania: risk maps of invasive alien plant species in Central Romania

    Directory of Open Access Journals (Sweden)

    Heike Zimmermann

    2015-01-01

    Full Text Available Using the MAXENT algorithm, we developed risk maps for eight invasive plant species in southern Transylvania, Romania, a region undergoing drastic land-use changes. Our findings show that invasion risk increased with landscape heterogeneity. Roads and agricultural areas were most prone to invasion, whereas forests were least at risk.

  12. Biogeographical plant-soil relations of invasive medusahead (Elymus caput-medusae)

    Science.gov (United States)

    Understanding the mechanisms that underlie the success of invasive plant species is integral to predicting and ameliorating their negative impacts. Many hypotheses have consequently been proposed to explain invasive behavior. This lack of consensus within invasion ecology can partially be attributed...

  13. Fort Collins Science Center: Invasive Species Science

    Science.gov (United States)

    Stohlgren, Tom

    2004-01-01

    Invasive, non-native species of plants, animals, and disease organisms adversely affect the ecosystems they enter. Like "biological wildfires," they can quickly spread, and they affect nearly all terrestrial and aquatic ecosystems. Invasive species have become the greatest environmental challenge of the 21st century in terms of economic, environmental, and human health costs, with an estimated impact in the U.S. of over $138 billion per year. Managers of Department of the Interior and other public and private lands and waters rank invasive species as their top resource management problem.

  14. Alien invasive vascular plants in South African natural and semi-natural environments : bibliography from 1830

    CSIR Research Space (South Africa)

    Moran, VC

    1982-12-01

    Full Text Available A compilation of references to research on alien invasive plants in South Africa is given. Crop weeds and indigenous plants are not included. Reference is made to 457 publications. Keyword listings and a keyword index are provided....

  15. Application of the EDYS Model to Evaluate Control Methods for Invasive Plants at Fort Carson, Colorado

    National Research Council Canada - National Science Library

    Hunter, Rachael G

    2004-01-01

    .... Non-indigenous invasive plants can also reduce and destroy forage for livestock and wildlife, displace native plant species, increase fire frequency, reduce recreational opportunities, and can poison domestic animals...

  16. REMOTE DETENTION OF INVASIVE AND OPPORTUNISTIC PLANT SPECIES IN GREAT LAKES COASTAL WETLANDS

    Science.gov (United States)

    Invasive and opportunistic plant species have been associated with wetland disturbance. Increases in the abundance of plant species such as common reed (Phragmites australis) in coastal Great Lakes wetlands are hypothesized to occur with shifts toward drier hydrologic regimes, fr...

  17. Foraging Behavior Interactions Between Two non-Native Social Wasps, Vespula germanica and V. vulgaris (Hymenoptera: Vespidae): Implications for Invasion Success?

    Science.gov (United States)

    Pereira, Ana Julia; Pirk, Gabriela I; Corley, Juan C

    2016-01-01

    Vespula vulgaris is an invasive scavenging social wasp that has very recently arrived in Patagonia (Argentina), a territory previously invaded - 35 yrs earlier - by another wasp, Vespula germanica Although V. vulgaris wasps possess features that could be instrumental in overcoming obstacles through several invasion stages, the presence of preestablished populations of V. germanica could affect their success. We studied the potential role played by V. germanica on the subsequent invasion process of V. vulgaris wasps in Patagonia by focusing on the foraging interaction between both species. This is because food searching and exploitation are likely to overlap strongly among Vespula wasps. We carried out choice tests where two types of baits were presented in a pairwise manner. We found experimental evidence supporting the hypothesis that V. germanica and V. vulgaris have an asymmetrical response to baits with stimuli simulating the presence of each other. V. germanica avoided baits with either visual or olfactory cues indicating the V. vulgaris presence. However, V. vulgaris showed no preference between baits with or lacking V. germanica stimuli. These results suggest that the presence of an established population of V. germanica may not contribute to added biotic resistance to V. vulgaris invasion. © The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America.

  18. Allelopathy and resource competition: the effects of Phragmites australis invasion in plant communities

    OpenAIRE

    Uddin, Md Nazim; Robinson, Randall William

    2017-01-01

    Background Phragmites australis, a ubiquitous wetland plant, has been considered one of the most invasive species in the world. Allelopathy appears to be one of the invasion mechanisms, however, the effects could be masked by resource competition among target plants. The difficulty of distinguishing allelopathy from resource competition among plants has hindered investigations of the role of phytotoxic allelochemicals in plant communities. This has been addressed via experiments conducted in ...

  19. Extensive analysis of native and non-native Centaurea solstitialis L. populations across the world shows no traces of polyploidization

    Directory of Open Access Journals (Sweden)

    Ramona-Elena Irimia

    2017-08-01

    Full Text Available Centaurea solstitialis L. (yellow starthistle, Asteraceae is a Eurasian native plant introduced as an exotic into North and South America, and Australia, where it is regarded as a noxious invasive. Changes in ploidy level have been found to be responsible for numerous plant biological invasions, as they are involved in trait shifts critical to invasive success, like increased growth rate and biomass, longer life-span, or polycarpy. C. solstitialis had been reported to be diploid (2n = 2x = 16 chromosomes, however, actual data are scarce and sometimes contradictory. We determined for the first time the absolute nuclear DNA content by flow cytometry and estimated ploidy level in 52 natural populations of C. solstitialis across its native and non-native ranges, around the world. All the C. solstitialis populations screened were found to be homogeneously diploid (average 2C value of 1.72 pg, SD = ±0.06 pg, with no significant variation in DNA content between invasive and non-invasive genotypes. We did not find any meaningful difference among the extensive number of native and non-native C. solstitialis populations sampled around the globe, indicating that the species invasive success is not due to changes in genome size or ploidy level.

  20. Extensive analysis of native and non-native Centaurea solstitialis L. populations across the world shows no traces of polyploidization.

    Science.gov (United States)

    Irimia, Ramona-Elena; Montesinos, Daniel; Eren, Özkan; Lortie, Christopher J; French, Kristine; Cavieres, Lohengrin A; Sotes, Gastón J; Hierro, José L; Jorge, Andreia; Loureiro, João

    2017-01-01

    Centaurea solstitialis L. (yellow starthistle, Asteraceae) is a Eurasian native plant introduced as an exotic into North and South America, and Australia, where it is regarded as a noxious invasive. Changes in ploidy level have been found to be responsible for numerous plant biological invasions, as they are involved in trait shifts critical to invasive success, like increased growth rate and biomass, longer life-span, or polycarpy. C . solstitialis had been reported to be diploid (2 n  = 2 x  = 16 chromosomes), however, actual data are scarce and sometimes contradictory. We determined for the first time the absolute nuclear DNA content by flow cytometry and estimated ploidy level in 52 natural populations of C . solstitialis across its native and non-native ranges, around the world. All the C. solstitialis populations screened were found to be homogeneously diploid (average 2C value of 1.72 pg, SD = ±0.06 pg), with no significant variation in DNA content between invasive and non-invasive genotypes. We did not find any meaningful difference among the extensive number of native and non-native C . solstitialis populations sampled around the globe, indicating that the species invasive success is not due to changes in genome size or ploidy level.

  1. Minimizing Risks of Invasive Alien Plant Species in Tropical Production Forest Management

    Directory of Open Access Journals (Sweden)

    Michael Padmanaba

    2014-08-01

    Full Text Available Timber production is the most pervasive human impact on tropical forests, but studies of logging impacts have largely focused on timber species and vertebrates. This review focuses on the risk from invasive alien plant species, which has been frequently neglected in production forest management in the tropics. Our literature search resulted in 114 publications with relevant information, including books, book chapters, reports and papers. Examples of both invasions by aliens into tropical production forests and plantation forests as sources of invasions are presented. We discuss species traits and processes affecting spread and invasion, and silvicultural practices that favor invasions. We also highlight potential impacts of invasive plant species and discuss options for managing them in production forests. We suggest that future forestry practices need to reduce the risks of plant invasions by conducting surveillance for invasive species; minimizing canopy opening during harvesting; encouraging rapid canopy closure in plantations; minimizing the width of access roads; and ensuring that vehicles and other equipment are not transporting seeds of invasive species. Potential invasive species should not be planted within dispersal range of production forests. In invasive species management, forewarned is forearmed.

  2. An Evolutionary Modelling Approach To Understanding The Factors Behind Plant Invasiveness And Community Susceptibility To Invasion

    DEFF Research Database (Denmark)

    Warren, John; Topping, Christopher John; James, Penri

    2011-01-01

    Ecologists have had limited success in understanding which introduced species may become invasive. An evolutionary model is used to investigate which traits are associated with invasiveness. Translocation experiments were simulated in which species were moved into similar but evolutionary younger...

  3. Limitations to postfire seedling establishment: The role of seeding technology, water availability, and invasive plant abundance

    Science.gov (United States)

    Jeremy J. James; Tony Svejcar

    2010-01-01

    Seeding rangeland following wildfire is a central tool managers use to stabilize soils and inhibit the spread of invasive plants. Rates of successful seeding on arid rangeland, however, are low. The objective of this study was to determine the degree to which water availability, invasive plant abundance, and seeding technology influence postfire seedling establishment...

  4. Plant–soil feedback induces shifts in biomass allocation in the invasive plant Chromolaena odorata

    NARCIS (Netherlands)

    te Beest, M.; Stevens, N.; Olff, H.; Van der Putten, W.H.

    2009-01-01

    1. Soil communities and their interactions with plants may play a major role in determining the success of invasive species. However, rigorous investigations of this idea using cross-continental comparisons, including native and invasive plant populations, are still scarce. 2. We investigated if

  5. Invasive alien plants used in the treatment of HIV/AIDS-related ...

    African Journals Online (AJOL)

    Results: A total of 38 invasive alien plant species belonging to 23 families were recorded to be used in the treatment of HIV/AIDS related symptoms. The largest proportion of recorded invasive alien plants belonged to the family Asteraceae with 16%. Roots were the most frequently used parts constituting 35% followed ...

  6. [Distribution pattern of riparian invasive plants in Luanhe Basin, North China and its relationship with environment].

    Science.gov (United States)

    Ren, Ying; He, Ping; Xu, Jie; Jia, Jiao

    2017-06-18

    In this study, the invasive plant species from the riparian vegetation in 56 sampling sites of Luanhe Basin were identified, and the correlations between their composition, spatial distribution and environmental factors were explored. In the basin, a total of 26 invasive species were registered, which belonged to 19 genera and 12 families, and 73.1% of them were annual plants. Asteraceae and Amaranthaceae were the two dominant families with the most invasive species, attributing to 50% of the total invasive species. Amaranthus retroflexus, Bidens frondosa and Chenopodium serotinum appeared with the highest frequencies. The number of invasive species and the invasive intensity at each site were significantly negatively correlated with the altitude. The distribution of invasive plants was significantly influenced by the intensity of human activities. The invasive plants were mainly distributed in the plain area, shallow mountainous area with many reservoirs, and the mountainous area with developed tourism around Chengde City, meanwhile, only few species with broad ecological amplitude existed in the plateau area. In general, species with higher invasive grades were mainly distributed in low and medium altitude areas below 400 m. Except for A. retroflexus, no high-grade invasive plants were discovered in high altitude area so far.

  7. The legacy of plant invasions: changes in the soil seed bank of invaded plant communities

    Czech Academy of Sciences Publication Activity Database

    Gioria, Margherita; Pyšek, Petr

    2016-01-01

    Roč. 66, č. 1 (2016), s. 40-53 ISSN 0006-3568 R&D Projects: GA ČR GA15-13491S; GA ČR GB14-36079G Grant - others:AV ČR(CZ) AP1002 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985939 Keywords : plant invasions * soil seed bank * impact Subject RIV: EH - Ecology, Behaviour Impact factor: 5.378, year: 2016

  8. Differences in dry weight partitioning and flowering phenology between native and non-native plants of purple loosestrife (Lythrum salicaria L.)

    Czech Academy of Sciences Publication Activity Database

    Bastlová, D.; Květ, Jan

    2002-01-01

    Roč. 197, - (2002), s. 332-340 ISSN 0367-2530 R&D Projects: GA ČR GA206/00/1113; GA MŠk OU94035; GA AV ČR KSK6005114 Institutional research plan: CEZ:AV0Z6005908; CEZ:MSM 123100004 Keywords : plant invasions * Eurasia * North America Subject RIV: EF - Botanics Impact factor: 1.132, year: 2002

  9. Interactive effects of herbivory and competition intensity determine invasive plant performance.

    Science.gov (United States)

    Huang, Wei; Carrillo, Juli; Ding, Jianqing; Siemann, Evan

    2012-10-01

    Herbivory can reduce plant fitness, and its effects can be increased by competition. Though numerous studies have examined the joint effects of herbivores and competitors on plant performance, these interactive effects are seldom considered in the context of plant invasions. Here, we examined variation in plant performance within a competitive environment in response to both specialist and generalist herbivores using Chinese tallow as a model species. We combined tallow plants from native and invasive populations to form all possible pairwise combinations, and designated invasive populations as stronger neighbours and native populations as weaker neighbours. We found that when no herbivory was imposed, invasive populations always had higher total biomass than natives, regardless of their neighbours, which is consistent with our assumption of increased competitive ability. Defoliation by either generalist or specialist herbivores suppressed plant growth but the effects of specialists were generally stronger for invasive populations. Invasive populations had their lowest biomass when fed upon by specialists while simultaneously competing with stronger neighbours. The root/shoot ratios of invasive populations were lower than those of native populations under almost all conditions, and invasive plants were taller than native plants overall, especially when herbivores were present, suggesting that invasive populations may adopt an "aboveground first" strategy to cope with herbivory and competition. These results suggest that release from herbivores, especially specialists, improves an invader's performance and helps to increase its competitive ability. Therefore, increasing interspecific competition intensity by planting a stronger neighbour while simultaneously releasing a specialist herbivore may be an especially effective method of managing invasive plants.

  10. Influence of Removal of a Non-native Tree Species Mimosa caesalpiniifolia Benth. on the Regenerating Plant Communities in a Tropical Semideciduous Forest Under Restoration in Brazil

    Science.gov (United States)

    Podadera, Diego S.; Engel, Vera L.; Parrotta, John A.; Machado, Deivid L.; Sato, Luciane M.; Durigan, Giselda

    2015-11-01

    Exotic species are used to trigger facilitation in restoration plantings, but this positive effect may not be permanent and these species may have negative effects later on. Since such species can provide a marketable product (firewood), their harvest may represent an advantageous strategy to achieve both ecological and economic benefits. In this study, we looked at the effect of removal of a non-native tree species ( Mimosa caesalpiniifolia) on the understory of a semideciduous forest undergoing restoration. We assessed two 14-year-old plantation systems (modified "taungya" agroforestry system; and mixed plantation using commercial timber and firewood tree species) established at two sites with contrasting soil properties in São Paulo state, Brazil. The experimental design included randomized blocks with split plots. The natural regeneration of woody species (height ≥0.2 m) was compared between managed (all M. caesalpiniifolia trees removed) and unmanaged plots during the first year after the intervention. The removal of M. caesalpiniifolia increased species diversity but decreased stand basal area. Nevertheless, the basal area loss was recovered after 1 year. The management treatment affected tree species regeneration differently between species groups. The results of this study suggest that removal of M. caesalpiniifolia benefited the understory and possibly accelerated the succession process. Further monitoring studies are needed to evaluate the longer term effects on stand structure and composition. The lack of negative effects of tree removal on the natural regeneration indicates that such interventions can be recommended, especially considering the expectations of economic revenues from tree harvesting in restoration plantings.

  11. Are invasive plants more competitive than native conspecifics? Patterns vary with competitors

    Science.gov (United States)

    Zheng, Yulong; Feng, Yulong; Valiente-Banuet, Alfonso; Li, Yangping; Liao, Zhiyong; Zhang, Jiaolin; Chen, Yajun

    2015-10-01

    Invasive plants are sometimes considered to be more competitive than their native conspecifics, according to the prediction that the invader reallocates resources from defense to growth due to liberation of natural enemies [‘Evolution of Increased Competitive Ability’ (EICA) hypothesis]. However, the differences in competitive ability may depend on the identity of competitors. In order to test the effects of competitors, Ageratina adenophora plants from both native and invasive ranges competed directly, and competed with native residents from both invasive (China) and native (Mexico) ranges respectively. Invasive A. adenophora plants were more competitive than their conspecifics from native populations when competing with natives from China (interspecific competition), but not when competing with natives from Mexico. Invasive A. adenophora plants also showed higher competitive ability when grown in high-density monoculture communities of plants from the same population (intrapopulation competition). In contrast, invasive A. adenophora plants showed lower competitive ability when competing with plants from native populations (intraspecific competition). Our results indicated that in the invasive range A. adenophora has evolved to effectively cope with co-occurring natives and high density environments, contributing to invasion success. Here, we showed the significant effects of competitors, which should be considered carefully when testing the EICA hypothesis.

  12. A regional assessment of white-tailed deer effects on plant invasion

    Energy Technology Data Exchange (ETDEWEB)

    Averill, Kristine M. [Ecology Intercollege Graduate Degree Program, The Pennsylvania State University, University Park, PA, USA; Department of Plant Sciences, The Pennsylvania State University, University Park, PA, USA; Mortensen, David A. [Ecology Intercollege Graduate Degree Program, The Pennsylvania State University, University Park, PA, USA; Department of Plant Sciences, The Pennsylvania State University, University Park, PA, USA; Smithwick, Erica A. H. [Ecology Intercollege Graduate Degree Program, The Pennsylvania State University, University Park, PA, USA; Department of Geography, The Pennsylvania State University, University Park, PA, USA; Kalisz, Susan [Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, USA; McShea, William J. [Smithsonian Conservation Biology Institute, Front Royal, VA, USA; Bourg, Norman A. [Smithsonian Conservation Biology Institute, Front Royal, VA, USA; Parker, John D. [Smithsonian Environmental Research Center, Edgewater, MD, USA; Royo, Alejandro A. [United States Department of Agriculture Forest Service, Northern Research Station, Irvine, PA, USA; Abrams, Marc D. [Ecology Intercollege Graduate Degree Program, The Pennsylvania State University, University Park, PA, USA; Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA, USA; Apsley, David K. [Department of Extension, The Ohio State University, Jackson, OH, USA; Blossey, Bernd [Department of Natural Resources, Cornell University, Ithaca, NY, USA; Boucher, Douglas H. [Department of Biology, Hood College, Frederick, MD, USA; Caraher, Kai L. [Department of Biology, Hood College, Frederick, MD, USA; DiTommaso, Antonio [Soil and Crop Sciences Section, Cornell University, Ithaca, NY, USA; Johnson, Sarah E. [Ecology Intercollege Graduate Degree Program, The Pennsylvania State University, University Park, PA, USA; Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA, USA; Masson, Robert [National Park Service, Morristown National Historical Park, Morristown, NJ, USA; Nuzzo, Victoria A. [Natural Area Consultants, Richford, NY, USA

    2017-12-07

    Herbivores can profoundly influence plant species assembly, including plant invasion, and resulting community composition. Population increases of native herbivores, e.g., white-tailed deer (Odocoileus virginianus), combined with burgeoning plant invasions raise concerns for native plant diversity and forest regeneration. While individual researchers typically test for the impact of deer on plant invasion at a few sites, the overarching influence of deer on plant invasion across regional scales is unclear. We tested the effects of deer on the abundance and diversity of introduced and native herbaceous and woody plants across 23 white-tailed deer research sites distributed across the east central and northeastern United States and representing a wide range of deer densities and invasive plant abundance and identity. Deer access/exclusion or deer population density did not affect introduced plant richness or community-level abundance. Native and total plant species richness, abundance (cover and stem density), and Shannon diversity were lower in deer-access vs. deer-exclusion plots. Among deer access plots, native species richness, native and total cover, and Shannon diversity (cover) declined as deer density increased. Deer access increased the proportion of introduced species cover (but not of species richness or stem density). As deer density increased, the proportion of introduced species richness, cover, and stem density all increased. Because absolute abundance of introduced plants was unaffected by deer, the increase in proportion of introduced plant abundance is likely an indirect effect of deer reducing native cover. Indicator species analysis revealed that deer access favored three introduced plant species, including Alliaria petiolata and Microstegium vimineum, as well as four native plant species. In contrast, deer exclusion favored three introduced plant species, including Lonicera japonica and Rosa multiflora, and fifteen native plant species. Overall

  13. Invasive plant species in the West Indies: geographical, ecological, and floristic insights.

    Science.gov (United States)

    Rojas-Sandoval, Julissa; Tremblay, Raymond L; Acevedo-Rodríguez, Pedro; Díaz-Soltero, Hilda

    2017-07-01

    The level of invasion (number or proportion of invasive species) in a given area depends on features of the invaded community, propagule pressure, and climate. In this study, we assess the invasive flora of nine islands in the West Indies to identify invasion patterns and evaluate whether invasive species diversity is related to geographical, ecological, and socioeconomic factors. We compiled a database of invasive plant species including information on their taxonomy, origin, pathways of introduction, habitats, and life history. This database was used to evaluate the similarity of invasive floras between islands and to identify invasion patterns at regional (West Indies) and local (island) scales. We found a total of 516 alien plant species that are invasive on at least one of the nine islands studied, with between 24 to 306 invasive species per island. The invasive flora on these islands includes a wide range of taxonomic groups, life forms, and habitats. We detected low similarity in invasive species diversity between islands, with most invasive species (>60%) occurring on a single island and 6% occurring on at least five islands. To assess the importance of different models in predicting patterns of invasive species diversity among islands, we used generalized linear models. Our analyses revealed that invasive species diversity was well predicted by a combination of island area and economic development (gross domestic product per capita and kilometers of paved roadways). Our results provide strong evidence for the roles of geographical, ecological, and socioeconomic factors in determining the distribution and spread of invasive species on these islands. Anthropogenic disturbance and economic development seem to be the major drivers facilitating the spread and predominance of invasive species over native species.

  14. Independent Effects of Invasive Shrubs and Deer Herbivory on Plant Community Dynamics

    Directory of Open Access Journals (Sweden)

    Jeffrey S. Ward

    2016-12-01

    Full Text Available Both invasive species and deer herbivory are recognized as locally important drivers of plant community dynamics. However, few studies have examined whether their effects are synergistic, additive, or antagonistic. At three study areas in southern New England, we examined the interaction of white-tailed deer (Odocoileus virginianus Zimmermann herbivory and three levels of invasive shrub control over seven growing seasons on the dynamics of nine herbaceous and shrub guilds. Although evidence of synergistic interactions was minimal, the separate effects of invasive shrub control and deer herbivory on plant community composition and dynamics were profound. Plant communities remained relatively unchanged where invasive shrubs were not treated, regardless if deer herbivory was excluded or not. With increasing intensity of invasive shrub control, native shrubs and forbs became more dominant where deer herbivory was excluded, and native graminoids became progressively more dominant where deer herbivory remained severe. While deer exclusion and intensive invasive shrub control increased native shrubs and forbs, it also increased invasive vines. Restoring native plant communities in areas with both established invasive shrub thickets and severe deer browsing will require an integrated management plan to eliminate recalcitrant invasive shrubs, reduce deer browsing intensity, and quickly treat other opportunistic invasive species.

  15. Modeling Hawaiian ecosystem degradation due to invasive plants under current and future climates.

    Directory of Open Access Journals (Sweden)

    Adam E Vorsino

    Full Text Available Occupation of native ecosystems by invasive plant species alters their structure and/or function. In Hawaii, a subset of introduced plants is regarded as extremely harmful due to competitive ability, ecosystem modification, and biogeochemical habitat degradation. By controlling this subset of highly invasive ecosystem modifiers, conservation managers could significantly reduce native ecosystem degradation. To assess the invasibility of vulnerable native ecosystems, we selected a proxy subset of these invasive plants and developed robust ensemble species distribution models to define their respective potential distributions. The combinations of all species models using both binary and continuous habitat suitability projections resulted in estimates of species richness and diversity that were subsequently used to define an invasibility metric. The invasibility metric was defined from species distribution models with 0.8; True Skill Statistic >0.75 as evaluated per species. Invasibility was further projected onto a 2100 Hawaii regional climate change scenario to assess the change in potential habitat degradation. The distribution defined by the invasibility metric delineates areas of known and potential invasibility under current climate conditions and, when projected into the future, estimates potential reductions in native ecosystem extent due to climate-driven invasive incursion. We have provided the code used to develop these metrics to facilitate their wider use (Code S1. This work will help determine the vulnerability of native-dominated ecosystems to the combined threats of climate change and invasive species, and thus help prioritize ecosystem and species management actions.

  16. Modeling Hawaiian ecosystem degradation due to invasive plants under current and future climates

    Science.gov (United States)

    Vorsino, Adam E.; Fortini, Lucas B.; Amidon, Fred A.; Miller, Stephen E.; Jacobi, James D.; Price, Jonathan P.; `Ohukani`ohi`a Gon, Sam; Koob, Gregory A.

    2014-01-01

    Occupation of native ecosystems by invasive plant species alters their structure and/or function. In Hawaii, a subset of introduced plants is regarded as extremely harmful due to competitive ability, ecosystem modification, and biogeochemical habitat degradation. By controlling this subset of highly invasive ecosystem modifiers, conservation managers could significantly reduce native ecosystem degradation. To assess the invasibility of vulnerable native ecosystems, we selected a proxy subset of these invasive plants and developed robust ensemble species distribution models to define their respective potential distributions. The combinations of all species models using both binary and continuous habitat suitability projections resulted in estimates of species richness and diversity that were subsequently used to define an invasibility metric. The invasibility metric was defined from species distribution models with 0.8; True Skill Statistic >0.75) as evaluated per species. Invasibility was further projected onto a 2100 Hawaii regional climate change scenario to assess the change in potential habitat degradation. The distribution defined by the invasibility metric delineates areas of known and potential invasibility under current climate conditions and, when projected into the future, estimates potential reductions in native ecosystem extent due to climate-driven invasive incursion. We have provided the code used to develop these metrics to facilitate their wider use (Code S1). This work will help determine the vulnerability of native-dominated ecosystems to the combined threats of climate change and invasive species, and thus help prioritize ecosystem and species management actions.

  17. Gopherus agassizii (Desert Tortoise). Non-native seed dispersal

    Science.gov (United States)

    Ennen, J.R.; Loughran, Caleb L.; Lovich, Jeffrey E.

    2011-01-01

    Sahara Mustard (Brassica tournefortii) is a non-native, highly invasive weed species of southwestern U.S. deserts. Sahara Mustard is a hardy species, which flourishes under many conditions including drought and in both disturbed and undisturbed habitats (West and Nabhan 2002. In B. Tellman [ed.], Invasive Plants: Their Occurrence and Possible Impact on the Central Gulf Coast of Sonora and the Midriff Islands in the Sea of Cortes, pp. 91–111. University of Arizona Press, Tucson). Because of this species’ ability to thrive in these habitats, B. tournefortii has been able to propagate throughout the southwestern United States establishing itself in the Mojave and Sonoran Deserts in Arizona, California, Nevada, and Utah. Unfortunately, naturally disturbed areas created by native species, such as the Desert Tortoise (Gopherus agassizii), within these deserts could have facilitated the propagation of B. tournefortii. (Lovich 1998. In R. G. Westbrooks [ed.], Invasive Plants, Changing the Landscape of America: Fact Book, p. 77. Federal Interagency Committee for the Management of Noxious and Exotic Weeds [FICMNEW], Washington, DC). However, Desert Tortoises have never been directly observed dispersing Sahara Mustard seeds. Here we present observations of two Desert Tortoises dispersing Sahara Mustard seeds at the interface between the Mojave and Sonoran deserts in California.

  18. Responses of the soil fungal communities to the co-invasion of two invasive species with different cover classes.

    Science.gov (United States)

    Wang, C; Zhou, J; Liu, J; Jiang, K; Xiao, H; Du, D

    2018-01-01

    Soil fungal communities play an important role in the successful invasion of non-native species. It is common for two or more invasive plant species to co-occur in invaded ecosystems. This study aimed to determine the effects of co-invasion of two invasive species (Erigeron annuus and Solidago canadensis) with different cover classes on soil fungal communities using high-throughput sequencing. Invasion of E. annuus and/or S. canadensis had positive effects on the sequence number, operational taxonomic unit (OTU) richness, Shannon diversity, abundance-based cover estimator (ACE index) and Chao1 index of soil fungal communities, but negative effects on the Simpson index. Thus, invasion of E. annuus and/or S. canadensis could increase diversity and richness of soil fungal communities but decrease dominance of some members of these communities, in part to facilitate plant further invasion, because high soil microbial diversity could increase soil functions and plant nutrient acquisition. Some soil fungal species grow well, whereas others tend to extinction after non-native plant invasion with increasing invasion degree and presumably time. The sequence number, OTU richness, Shannon diversity, ACE index and Chao1 index of soil fungal communities were higher under co-invasion of E. annuus and S. canadensis than under independent invasion of either individual species. The co-invasion of the two invasive species had a positive synergistic effect on diversity and abundance of soil fungal communities, partly to build a soil microenvironment to enhance competitiveness of the invaders. The changed diversity and community under co-invasion could modify resource availability and niche differentiation within the soil fungal communities, mediated by differences in leaf litter quality and quantity, which can support different fungal/microbial species in the soil. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

  19. Long-term changes in communities of native coccinellids: population fluctuations and the effect of competition from an invasive non-native species

    Czech Academy of Sciences Publication Activity Database

    Honěk, A.; Martínková, Z.; Dixon, Anthony F. G.; Roy, H. E.; Pekárek, S.

    2016-01-01

    Roč. 9, č. 3 (2016), s. 202-209 ISSN 1752-458X R&D Projects: GA ČR GA14-26561S; GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : ladybird harmonia-axyridis * coleoptera-coccinellidae * intraguild predation * habitat preferences * central-europe * spread * ladybeetle * beetles * history * decline * Adalia * Anatis * Calvia * Coccinella * Halyzia * Harmonia * intraguild predation * invasive alien species * ladybird beetles * Propylea Subject RIV: EH - Ecology, Behaviour Impact factor: 1.840, year: 2016

  20. Plant Invasions Associated with Change in Root-Zone Microbial Community Structure and Diversity.

    Directory of Open Access Journals (Sweden)

    Richard R Rodrigues

    Full Text Available The importance of plant-microbe associations for the invasion of plant species have not been often tested under field conditions. The research sought to determine patterns of change in microbial communities associated with the establishment of invasive plants with different taxonomic and phenetic traits. Three independent locations in Virginia, USA were selected. One site was invaded by a grass (Microstegium vimineum, another by a shrub (Rhamnus davurica, and the third by a tree (Ailanthus altissima. The native vegetation from these sites was used as reference. 16S rRNA and ITS regions were sequenced to study root-zone bacterial and fungal communities, respectively, in invaded and non-invaded samples and analyzed using Quantitative Insights Into Microbial Ecology (QIIME. Though root-zone microbial community structure initially differed across locations, plant invasion shifted communities in similar ways. Indicator species analysis revealed that Operational Taxonomic Units (OTUs closely related to Proteobacteria, Acidobacteria, Actinobacteria, and Ascomycota increased in abundance due to plant invasions. The Hyphomonadaceae family in the Rhodobacterales order and ammonia-oxidizing Nitrospirae phylum showed greater relative abundance in the invaded root-zone soils. Hyphomicrobiaceae, another bacterial family within the phyla Proteobacteria increased as a result of plant invasion, but the effect associated most strongly with root-zones of M. vimineum and R. davurica. Functional analysis using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt showed bacteria responsible for nitrogen cycling in soil increased in relative abundance in association with plant invasion. In agreement with phylogenetic and functional analyses, greater turnover of ammonium and nitrate was associated with plant invasion. Overall, bacterial and fungal communities changed congruently across plant invaders, and support the hypothesis that

  1. Effects of an invasive plant on population dynamics in toads.

    Science.gov (United States)

    Greenberg, Daniel A; Green, David M

    2013-10-01

    When populations decline in response to unfavorable environmental change, the dynamics of their population growth shift. In populations that normally exhibit high levels of variation in recruitment and abundance, as do many amphibians, declines may be difficult to identify from natural fluctuations in abundance. However, the onset of declines may be evident from changes in population growth rate in sufficiently long time series of population data. With data from 23 years of study of a population of Fowler's toad (Anaxyrus [ = Bufo] fowleri) at Long Point, Ontario (1989-2011), we sought to identify such a shift in dynamics. We tested for trends in abundance to detect a change point in population dynamics and then tested among competing population models to identify associated intrinsic and extrinsic factors. The most informative models of population growth included terms for toad abundance and the extent of an invasive marsh plant, the common reed (Phragmites australis), throughout the toads' marshland breeding areas. Our results showed density-dependent growth in the toad population from 1989 through 2002. After 2002, however, we found progressive population decline in the toads associated with the spread of common reeds and consequent loss of toad breeding habitat. This resulted in reduced recruitment and population growth despite the lack of significant loss of adult habitat. Our results underscore the value of using long-term time series to identify shifts in population dynamics coincident with the advent of population decline. © 2013 Society for Conservation Biology.

  2. 77 FR 49893 - Endangered and Threatened Wildlife and Plants; Determination of Status for the Gierisch Mallow...

    Science.gov (United States)

    2012-08-17

    ... impacts, such as regulations governing mining operations; The spread of nonnative, invasive plant species... gypsum mining necessarily involves removal of the topsoil, eliminating, at least temporarily, the species..., invasive species such as cheatgrass and red brome. Livestock have been implicated in the spread of weeds...

  3. An invasive plant alters phenotypic selection on the vegetative growth of a native congener.

    Science.gov (United States)

    Beans, Carolyn M; Roach, Deborah A

    2015-02-01

    The ecological consequences of plant competition have frequently been tested, but the evolutionary outcomes of these interactions have gone largely unexplored. The study of species invasions can make an important contribution to this field of research by allowing us to watch ecological and evolutionary processes unfold as a novel species is integrated into a plant community. We explored the ecological and evolutionary impact of an invasive jewelweed, Impatiens glandulifera, on a closely related native congener, I. capensis and asked: (1) Does the presence of the invasive jewelweed alter the fitness of native jewelweed populations? (2) Does the invasive jewelweed affect the vegetative growth of the native congener? and (3) Does the invasive jewelweed alter phenotypic selection on the vegetative traits of the native congener? We used a greenhouse competition experiment, an invasive species removal field experiment, and a survey of natural populations. We show that when the invasive jewelweed is present, phenotypic selection favors native jewelweed individuals investing less in rapid upward growth and more in branching and fruiting potential through the production of nodes. This research demonstrates that invasive plants have the potential to greatly alter natural selection on native competitors. Studies investigating altered selection in invaded communities can reveal the potential evolutionary impact of invasive competitors, while deepening our understanding of the more general role of competition in driving plant evolution and permitting species coexistence. © 2015 Botanical Society of America, Inc.

  4. 77 FR 12002 - Mount Baker-Snoqualmie National Forest Site-Specific Invasive Plant Treatment Project and Forest...

    Science.gov (United States)

    2012-02-28

    ... Invasive Plant Treatment Project and Forest Plan Amendment Number 28 AGENCY: Forest Service, USDA. ACTION... Forest. The current Forest-wide treatment approach pre-dates the Pacific Northwest Region Invasive Plant... interdisciplinary analysis: (1) Whether or not to authorize site- specific invasive plant treatments using...

  5. Interactive effect of herbivory and competition on the invasive plant Mikania micrantha.

    Science.gov (United States)

    Li, Junmin; Xiao, Tao; Zhang, Qiong; Dong, Ming

    2013-01-01

    A considerable number of host-specific biological control agents fail to control invasive plants in the field, and exploring the mechanism underlying this phenomenon is important and helpful for the management of invasive plants. Herbivory and competition are two of the most common biotic stressors encountered by invasive plants in their recipient communities. We predicted that the antagonistic interactive effect between herbivory and competition would weaken the effect of herbivory on invasive plants and result in the failure of herbivory to control invasive plants. To examine this prediction, thus, we conducted an experiment in which both invasive Mikania micrantha and native Coix lacryma-job i were grown together and subjected to herbivory-mimicking defoliation. Both defoliation and competition had significantly negative effects on the growth of the invader. However, the negative effect of 75% respective defoliation on the above- and below-ground biomass of Mikania micrantha was alleviated by presence of Coix lacryma-jobi. The negative effect of competition on the above- and below-ground biomass was equally compensated at 25%, 50% and 100% defoliation and overcompensated at 75% defoliation. The interactive effect was antagonistic and dependent on the defoliation intensity, with the maximum effect at 75% defoliation. The antagonistic interaction between defoliation and competition appears to be able to release the invader from competition, thus facilitating the invasiveness of Mikania, a situation that might make herbivory fail to inhibit the growth of invasive Mikania in the invaded community.

  6. Soil fungal abundance and diversity: another victim of the invasive plant Centaurea maculosa.

    Science.gov (United States)

    Broz, Amanda K; Manter, Daniel K; Vivanco, Jorge M

    2007-12-01

    Interactions between plants and soil microbes are important determinants of both above- and belowground community composition, and ultimately ecosystem function. As exotic plants continue to invade and modify native plant communities, there has been increasing interest in determining the influence of exotic invasives on native soil microbial communities. Here, using highly sensitive molecular techniques, we examine fungal abundance and diversity in the soil surrounding a particularly aggressive invasive plant species in North America, Centaurea maculosa Lam. In mixed stands, we show that this invasive weed can alter the native fungal community composition within its own rhizosphere and that of neighboring native plants. At higher densities, the effect of C. maculosa on native soil fungal communities was even greater. Our results demonstrate that this invasive weed can have significant effects not only on visible aboveground biodiversity but also on the native soil microbial community that extends beyond its rhizosphere.

  7. Competitive impacts of an invasive nectar thief on plant-pollinator mutualisms

    Science.gov (United States)

    Hanna, Cause; Foote, David; Kremen, Claire

    2014-01-01

    Plant–pollinator mutualisms are disrupted by a variety of competitive interactions between introduced and native floral visitors. The invasive western yellowjacket wasp, Vespula pensylvanica, is an aggressive nectar thief of the dominant endemic Hawaiian tree species, Metrosideros polymorpha. We conducted a large-scale, multiyear manipulative experiment to investigate the impacts of V. pensylvanica on the structure and behavior of the M. polymorpha pollinator community, including competitive mechanisms related to resource availability. Our results demonstrate that V. pensylvanica, through both superior exploitative and interference competition, influences resource partitioning and displaces native and nonnative M. polymorpha pollinators. Furthermore, the restructuring of the pollinator community due to V. pensylvanica competition and predation results in a significant decrease in the overall pollinator effectiveness and fruit set of M. polymorpha. This research highlights both the competitive mechanisms and contrasting effects of social insect invaders on plant–pollinator mutualisms and the role of competition in pollinator community structure.

  8. Relative floral density of an invasive plant affects pollinator foraging behaviour on a native plant

    Directory of Open Access Journals (Sweden)

    Amy Marie Iler

    2014-08-01

    Full Text Available Interactions between invasive and native plants for pollinators vary from competition to facilitation of pollination of native plants. Theory predicts that relative floral densities should account for some of this variation in outcomes, with facilitation at low floral densities and competition at high floral densities of the invader. We tested this prediction by quantifying pollination and female reproductive success of a native herb, Geranium maculatum, in three experimental arrays that varied in floral density of the invasive shrub Lonicera maackii: control (no L. maackii, low floral density of L. maackii, and high floral density of L. maackii. A low density of L. maackii flowers was associated with an increase in pollinator visitation rate to G. maculatum flowers and an increase in conspecific pollen deposition compared to controls and high density arrays. Increased visitation rates were not associated with an increase in the number of visitors to low density arrays, suggesting instead that a behavioural switch in visitation within the array accounted for increased pollen deposition. In contrast, the only evidence of competition in high density arrays was a shorter duration of visits to G. maculatum flowers relative to the other treatments. The number of seeds per flower did not vary among treatments, although trends in seeds per flower were consistent with patterns of pollinator foraging behaviour. Given increased pollinator visits and pollen deposition at a low density of the invader, our study indicates that complete eradication of invasives as a management or restoration technique may have unintended negative consequences for pollination of native plants.

  9. Public attitude in the city of Belgrade towards invasive alien plant species

    Directory of Open Access Journals (Sweden)

    Tomićević Jelena

    2012-01-01

    Full Text Available Biological invasions are seen as a major threat to biodiversity at a global level, while the number of new invasions is increasing at an alarming rate. Raising the awareness of the public, academic world and policy makers about the dangers caused by invasive species, is essential for the creation of the support needed to implement and coordinate the policies necessary to address this problem. The aim of this study is to determine the level of local public awareness of the existence of these plant species, examine the public attitude towards alien invasive plant species and willingness to get involved in the prevention of their spreading. The survey was conducted in four nurseries on the territory of the City of Belgrade and the investigation dealt only with alien invasive woody plant species. Thirty customers were questioned in each of the four nurseries. The results show that local public is uninformed on the issue of invasive plant species. It is necessary to constantly and intensively raise their awareness of this issue, as well as the awareness of harmful consequences that may occur due to the uncontrolled spreading of alien invasive species. This refers not only to the population that visits the nurseries and buys the plants there and to those employed in plant production and selling, but also to the whole local public and decision makers.

  10. Invasive plant suppresses the growth of native tree seedlings by disrupting belowground mutualisms.

    Directory of Open Access Journals (Sweden)

    Kristina A Stinson

    2006-05-01

    Full Text Available The impact of exotic species on native organisms is widely acknowledged, but poorly understood. Very few studies have empirically investigated how invading plants may alter delicate ecological interactions among resident species in the invaded range. We present novel evidence that antifungal phytochemistry of the invasive plant, Alliaria petiolata, a European invader of North American forests, suppresses native plant growth by disrupting mutualistic associations between native canopy tree seedlings and belowground arbuscular mycorrhizal fungi. Our results elucidate an indirect mechanism by which invasive plants can impact native flora, and may help explain how this plant successfully invades relatively undisturbed forest habitat.

  11. Recognition of pyrrolizidine alkaloid esters in the invasive aquatic plant Gymnocoronis spilanthoides (Asteraceae)

    Science.gov (United States)

    Introduction – The freshwater aquatic plant Gymnocoronis spilanthoides (Senegal tea plant, jazmín del bañado, Falscher Wasserfreund) is an invasive plant in many countries. Behavioural observations of pyrrolizidine alkaloid-pharmacophagous butterflies suggested the presence of pyrrolizidine alkaloid...

  12. Grassland Arthropods Are Controlled by Direct and Indirect Interactions with Cattle but Are Largely Unaffected by Plant Provenance.

    Science.gov (United States)

    Farrell, Kelly Anne; Harpole, W Stanley; Stein, Claudia; Suding, Katharine N; Borer, Elizabeth T

    2015-01-01

    Cattle grazing and invasion by non-native plant species are globally-ubiquitous changes occurring to plant communities that are likely to reverberate through whole food webs. We used a manipulative field experiment to quantify how arthropod community structure differed in native and non-native California grassland communities in the presence and absence of grazing. The arthropod community was strongly affected by cattle grazing: the biovolume of herbivorous arthropods was 79% higher in grazed than ungrazed plots, whereas the biovolume of predatory arthropods was 13% higher in ungrazed plots. In plots where non-native grasses were grazed, arthropod biovolume increased, possibly in response to increased plant productivity or increased nutritional quality of rapidly-growing annual plants. Grazing may thus affect plant biomass both through the direct removal of biomass, and through arthropod-mediated impacts. We also expected the arthropod community to differ between native and non-native plant communities; surprisingly, arthropod richness and diversity did not vary consistently between these grass community types, although arthropod abundance was slightly higher in plots with native and ungrazed grasses. These results suggest that whereas cattle grazing affects the arthropod community via direct and indirect pathways, arthropod community changes commonly associated with non-native plant invasions may not be due to the identity or dominance of the invasive species in those systems, but to accompanying changes in plant traits or functional group composition, not seen in this experiment because of the similarity of the plant communities.

  13. Grassland Arthropods Are Controlled by Direct and Indirect Interactions with Cattle but Are Largely Unaffected by Plant Provenance.

    Directory of Open Access Journals (Sweden)

    Kelly Anne Farrell

    Full Text Available Cattle grazing and invasion by non-native plant species are globally-ubiquitous changes occurring to plant communities that are likely to reverberate through whole food webs. We used a manipulative field experiment to quantify how arthropod community structure differed in native and non-native California grassland communities in the presence and absence of grazing. The arthropod community was strongly affected by cattle grazing: the biovolume of herbivorous arthropods was 79% higher in grazed than ungrazed plots, whereas the biovolume of predatory arthropods was 13% higher in ungrazed plots. In plots where non-native grasses were grazed, arthropod biovolume increased, possibly in response to increased plant productivity or increased nutritional quality of rapidly-growing annual plants. Grazing may thus affect plant biomass both through the direct removal of biomass, and through arthropod-mediated impacts. We also expected the arthropod community to differ between native and non-native plant communities; surprisingly, arthropod richness and diversity did not vary consistently between these grass community types, although arthropod abundance was slightly higher in plots with native and ungrazed grasses. These results suggest that whereas cattle grazing affects the arthropod community via direct and indirect pathways, arthropod community changes commonly associated with non-native plant invasions may not be due to the identity or dominance of the invasive species in those systems, but to accompanying changes in plant traits or functional group composition, not seen in this experiment because of the similarity of the plant communities.

  14. Changes in soil bacterial communities induced by the invasive plant Pennisetum setaceum in a semiarid environment

    Science.gov (United States)

    Rodriguez-Caballero, Gema; Caravaca, Fuensanta; del Mar Alguacil, María; Fernández-López, Manuel; José Fernández-González, Antonio; García-Orenes, Fuensanta; Roldán, Antonio

    2016-04-01

    Invasive alien species are considered as a global threat being among the main causes of biodiversity loss. Plant invasions have been extensively studied from different disciplines with the purpose of identifying predictor traits of invasiveness and finding solutions. However, less is known about the implication of the rhizosphere microbiota in these processes, even when it is well known the importance of the interaction between plant rhizosphere and microbial communities. The objective of this study was to determine whether native and invasive plants support different bacterial communities in their rhizospheres and whether there are bacterial indicator species that might be contributing to the invasion process of these ecosystems. We carried out a study in five independent locations under Mediterranean semiarid conditions, where the native Hyparrhenia hirta is being displaced by Pennisetum setaceum, an aggressive invasive Poaceae and soil bacterial communities were amplified and 454-pyrosequenced. Changes in the composition and structure of the bacterial communities, owing to the invasive status of the plant, were detected when the richness and alpha-diversity estimators were calculated as well as when we analyzed the PCoA axes scores. The Indicator Species Analysis results showed a higher number of indicators for invaded communities at all studied taxonomic levels. In conclusion, the effect of the invasiveness and its interaction with the soil location has promoted shifts in the rhizosphere bacterial communities which might be facilitating the invader success in these ecosystems.

  15. Race to Displace: A Game to Model the Effects of Invasive Species on Plant Communities

    Science.gov (United States)

    Hopwood, Jennifer L.; Flowers, Susan K.; Seidler, Katie J.; Hopwood, Erica L.

    2013-01-01

    Invasive species are a substantial threat to biodiversity. Educating students about invasive species introduces fundamental concepts in biology, ecology, and environmental science. In the Race to Displace game, students assume the characteristics of select native or introduced plants and experience first hand the influences of species interactions…

  16. Apparent competition with an invasive plant hastens the extinction of an endangered lupine.

    Science.gov (United States)

    Dangremond, Emily M; Pardini, Eleanor A; Knight, Tiffany M

    2010-08-01

    Invasive plants may compete with native plants by increasing the pressure of native consumers, a mechanism known as "apparent competition." Apparent competition can be as strong as or stronger than direct competition, but the role of apparent competition has rarely been examined in biological invasions. We used four years of demographic data and seed-removal experiments to determine if introduced grasses caused elevated levels of seed consumption on native plant species in a coastal dune system in California, USA. We show that the endangered, coastal dune plant Lupinus tidestromii experiences high levels of pre-dispersal seed consumption by the native rodent Peromyscus maniculatus due to its proximity to the invasive grass, Ammophila arenaria. We use stage-structured, stochastic population models to project that two of three study populations will decline toward extinction under ambient levels of consumption. For one of these declining populations, a relatively small decrease in consumption pressure should allow for persistence. We show that apparent competition with an invasive species significantly decreases the population growth rate and persistence of a native species. We expect that apparent competition is an important mechanism in other ecosystems because invasive plants often change habitat structure and plant-consumer interactions. Possible implications of the apparent-competition mechanism include selective extinction of species preferred by seed consumers in the presence of an invasive species and biological homogenization of communities toward non-preferred native plant species.

  17. Alien plant invasion in mixed-grass prairie: Effects of vegetation type and anthropogenic disturbance

    Science.gov (United States)

    Larson, D.L.; Anderson, P.J.; Newton, W.

    2001-01-01

    The ability of alien plant species to invade a region depends not only on attributes of the plant, but on characteristics of the habitat being invaded. Here, we examine characteristics that may influence the success of alien plant invasion in mixed-grass prairie at Theodore Roosevelt National Park, in western North Dakota, USA. The park consists of two geographically separate units with similar vegetation types and management history, which allowed us to examine the effects of native vegetation type, anthropogenic disturbance, and the separate park units on the invasion of native plant communities by alien plant species common to counties surrounding both park units. If matters of chance related to availability of propagules and transient establishment opportunities determine the success of invasion, park unit and anthropogenic disturbance should better explain the variation in alien plant frequency. If invasibility is more strongly related to biotic or physical characteristics of the native plant communities, models of alien plant occurrence should include vegetation type as an explanatory variable. We examined >1300 transects across all vegetation types in both units of the park. Akaike's Information Criterion (AIC) indicated that the fully parameterized model, including the interaction among vegetation type, disturbance, and park unit, best described the distribution of both total number of alien plants per transect and frequency of alien plants on transects where they occurred. Although all vegetation types were invaded by alien plants, mesic communities had both greater numbers and higher frequencies of alien plants than did drier communities. A strong element of stochasticity, reflected in differences in frequencies of individual species between the two park units, suggests that prediction of risk of invasion will always involve uncertainty. In addition, despite well-documented associations between anthropogenic disturbance and alien plant invasion, five of

  18. Economic Impacts of Non-Native Forest Insects in the Continental United States

    Science.gov (United States)

    Juliann E. Aukema; Brian. Leung; Kent Kovacs; Corey Chivers; Jeffrey Englin; Susan J. Frankel; Robert G. Haight; Thomas P. Holmes; Andrew M. Liebhold; Deborah G. McCullough; Betsy. Von Holle

    2011-01-01

    Reliable estimates of the impacts and costs of biological invasions are critical to developing credible management, trade and regulatory policies. Worldwide, forests and urban trees provide important ecosystem services as well as economic and social benefits, but are threatened by non-native insects. More than 450 non-native forest insects are established in the United...

  19. Proposed prioritization system for the management of invasive alien plants in South Africa

    CSIR Research Space (South Africa)

    Robertson, MP

    2003-01-01

    Full Text Available system described in this article was designed to assess objectively research and control priorities of invasive alien plants at a national scale in South Africa. The evaluation consists of seventeen criteria, grouped into five modules that assess...

  20. Invasive alien plants and South African rivers: a proposed approach to the prioritisation of control operations

    CSIR Research Space (South Africa)

    Van Wilgen, BW

    2007-01-01

    Full Text Available Parallel initiatives in South Africa have been addressing the prioritisation and management of invasive alien plant species, the prioritisation of rivers for the conservation of biodiversity, and broad-scale planning for water resource management...

  1. Plant invasions in protected areas of tropical pacific islands, with special reference to Hawaii

    Science.gov (United States)

    Hughes, R. Flint; Meyer, Jean-Yves; Loope, Lloyd L.

    2013-01-01

    Isolated tropical islands are notoriously vulnerable to plant invasions. Serious management for protection of native biodiversity in Hawaii began in the 1970s, arguably at Hawaii Volcanoes National Park. Concerted alien plant management began there in the 1980s and has in a sense become a model for protected areas throughout Hawaii and Pacific Island countries and territories. We review the relative successes of their strategies and touch upon how their experience has been applied elsewhere. Protected areas in Hawaii are fortunate in having relatively good resources for addressing plant invasions, but many invasions remain intractable, and invasions from outside the boundaries continue from a highly globalised society with a penchant for horticultural novelty. There are likely few efforts in most Pacific Islands to combat alien plant invasions in protected areas, but such areas may often have fewer plant invasions as a result of their relative remoteness and/or socio-economic development status. The greatest current needs for protected areas in this region may be for establishment of yet more protected areas, for better resources to combat invasions in Pacific Island countries and territories, for more effective control methods including biological control programme to contain intractable species, and for meaningful efforts to address prevention and early detection of potential new invaders.

  2. Invasive plants and enemy release: Evolution of trait means and trait correlations in Ulex europaeus

    OpenAIRE

    Hornoy , Benjamin; Tarayre , Michèle; Hervé , Maxime; Gigord , Luc; Atlan , Anne

    2011-01-01

    International audience; Several hypotheses that attempt to explain invasive processes are based on the fact that plants have been introduced without their natural enemies. Among them, the EICA (Evolution of Increased Competitive Ability) hypothesis is the most influential. It states that, due to enemy release, exotic plants evolve a shift in resource allocation from defence to reproduction or growth. In the native range of the invasive species Ulex europaeus, traits involved in reproduction a...

  3. Ridgefield Complex - Invasive Plant ED/RR Search 2015

    Data.gov (United States)

    Department of the Interior — The proposed project is a part of the Gorge NWRs’ invasives management program and will help achieve goals and improve targeted habitats identified in the Refuges’...

  4. Responses of Two Invasive Plants Under Various Microclimate Conditions in the Seoul Metropolitan Region

    Science.gov (United States)

    Song, Uhram; Mun, Saeromi; Ho, Chang-Hoi; Lee, Eun Ju

    2012-06-01

    The possible consequences of global warming on plant communities and ecosystems have wide-ranging ramifications. We examined how environmental change affects plant growth as a function of the variations in the microclimate along an urban-suburban climate gradient for two allergy-inducing, invasive plants, Humulus japonicus and Ambrosia artemisiifolia var. elatior. The environmental factors and plant growth responses were measured at two urban sites (Gangbuk and Seongbuk) and two suburban sites (Goyang and Incheon) around Seoul, South Korea. The mean temperatures and CO2 concentrations differed significantly between the urban (14.8 °C and 439 ppm CO2) and suburban (13.0 °C and 427 ppm CO2) sites. The soil moisture and nitrogen contents of the suburban sites were higher than those at the urban sites, especially for the Goyang site. The two invasive plants showed significantly higher biomasses and nitrogen contents at the two urban sites. We conducted experiments in a greenhouse to confirm the responses of the plants to increased temperatures, and we found consistently higher growth rates under conditions of higher temperatures. Because we controlled the other factors, the better performance of the two invasive plants appears to be primarily attributable to their responses to temperature. Our study demonstrates that even small temperature changes in the environment can confer significant competitive advantages to invasive species. As habitats become urbanized and warmer, these invasive plants should be able to displace native species, which will adversely affect people living in these areas.

  5. Plant functional traits of dominant native and invasive species in mediterranean-climate ecosystems.

    Science.gov (United States)

    Funk, Jennifer L; Standish, Rachel J; Stock, William D; Valladares, Fernando

    2016-01-01

    The idea that dominant invasive plant species outperform neighboring native species through higher rates of carbon assimilation and growth is supported by several analyses of global data sets. However, theory suggests that native and invasive species occurring in low-resource environments will be functionally similar, as environmental factors restrict the range of observed physiological and morphological trait values. We measured resource-use traits in native and invasive plant species across eight diverse vegetation communities distributed throughout the five mediterranean-climate regions, which are drought prone and increasingly threatened by human activities, including the introduction of exotic species. Traits differed strongly across the five regions. In regions with functional differences between native and invasive species groups, invasive species displayed traits consistent with high resource acquisition; however, these patterns were largely attributable to differences in life form. We found that species invading mediterranean-climate regions were more likely to be annual than perennial: three of the five regions were dominated by native woody species and invasive annuals. These results suggest that trait differences between native and invasive species are context dependent and will vary across vegetation communities. Native and invasive species within annual and perennial groups had similar patterns of carbon assimilation and resource use, which contradicts the widespread idea that invasive species optimize resource acquisition rather than resource conservation. .

  6. Potential impacts of year-round sampling on monitoring presence- absence of invasive flora in the southern United States

    Science.gov (United States)

    Christopher M. Oswalt; Sonja N. Oswalt; W. Keith Moser

    2012-01-01

    Studies suggest that the southern United States is an area of primary concern with regards to the spread of nonnative invasive plant species. Recent data show that species such as Japanese honeysuckle (Lonicera japonica) and Nepalese browntop (Microstegium vimineum) are invading forests and displacing native species throughout the...

  7. The role of CVS (and FIA) data and genetic tests in assessing species vulnerability to invasive pests and changing climate

    Science.gov (United States)

    R.A. Sniezko; H.E. Lintz

    2017-01-01

    United States tree species and their associated ecosystems, managed forests, and urban plantings are increasingly vulnerable to non-native invasive pathogens and insects as well as effects associated with a changing climate. Some species, such as whitebark pine (Pinus albicaulis), have been proposed for listing under the Endangered Species Act. To...

  8. Improving methods to evaluate the impacts of plant invasions: lessons from 40 years of research

    Science.gov (United States)

    Stricker, Kerry Bohl; Hagan, Donald; Flory, S. Luke

    2015-01-01

    Methods used to evaluate the ecological impacts of biological invasions vary widely from broad-scale observational studies to removal experiments in invaded communities and experimental additions in common gardens and greenhouses. Different methods provide information at diverse spatial and temporal scales with varying levels of reliability. Thus, here we provide a synthetic and critical review of the methods used to evaluate the impacts of plant invasions and provide recommendations for future research. We review the types of methods available and report patterns in methods used, including the duration and spatial scale of studies and plant functional groups examined, from 410 peer-reviewed papers published between 1971 and 2011. We found that there has been a marked increase in papers published on plant invasion impacts since 2003 and that more than half of all studies employed observational methods while impacts of invasive forbs and graminoids while impacts, we argue that longer-term experimental research and more studies that use predictive modelling and evaluate impacts of invasions on ecosystem processes and fauna are needed. Combining broad-scale observational studies with experiments and predictive modelling may provide the most insight into invasion impacts for policy makers and land managers seeking to reduce the effects of plant invasions. PMID:25829379

  9. Impact of nonnative feral pig removal on soil structure and nutrient availability in Hawaiian tropical montane wet forests

    Science.gov (United States)

    Michael S. Long; Creighton M. Litton; Christian P. Giardina; Jonathan Deenik; Rebecca J. Cole; Jed P. Sparks

    2017-01-01

    Conservation and restoration of ecosystems impacted by nonnative ungulates increasingly involves their removal and exclusion. While the influence of nonnative ungulate removal on plant communities is commonly monitored, impacts on underlying ecological processes are seldom quantified. Here we examined how nonnative feral pig (

  10. Low genetic diversity despite multiple introductions of the invasive plant species Impatiens glandulifera in Europe.

    Science.gov (United States)

    Hagenblad, Jenny; Hülskötter, Jennifer; Acharya, Kamal Prasad; Brunet, Jörg; Chabrerie, Olivier; Cousins, Sara A O; Dar, Pervaiz A; Diekmann, Martin; De Frenne, Pieter; Hermy, Martin; Jamoneau, Aurélien; Kolb, Annette; Lemke, Isgard; Plue, Jan; Reshi, Zafar A; Graae, Bente Jessen

    2015-08-20

    Invasive species can be a major threat to native biodiversity and the number of invasive plant species is increasing across the globe. Population genetic studies of invasive species can provide key insights into their invasion history and ensuing evolution, but also for their control. Here we genetically characterise populations of Impatiens glandulifera, an invasive plant in Europe that can have a major impact on native plant communities. We compared populations from the species' native range in Kashmir, India, to those in its invaded range, along a latitudinal gradient in Europe. For comparison, the results from 39 other studies of genetic diversity in invasive species were collated. Our results suggest that I. glandulifera was established in the wild in Europe at least twice, from an area outside of our Kashmir study area. Our results further revealed that the genetic diversity in invasive populations of I. glandulifera is unusually low compared to native populations, in particular when compared to other invasive species. Genetic drift rather than mutation seems to have played a role in differentiating populations in Europe. We find evidence of limitations to local gene flow after introduction to Europe, but somewhat less restrictions in the native range. I. glandulifera populations with significant inbreeding were only found in the species' native range and invasive species in general showed no increase in inbreeding upon leaving their native ranges. In Europe we detect cases of migration between distantly located populations. Human activities therefore seem to, at least partially, have facilitated not only introductions, but also further spread of I. glandulifera across Europe. Although multiple introductions will facilitate the retention of genetic diversity in invasive ranges, widespread invasive species can remain genetically relatively invariant also after multiple introductions. Phenotypic plasticity may therefore be an important component of the

  11. A Spatially Explicit Dual-Isotope Approach to Map Regions of Plant-Plant Interaction after Exotic Plant Invasion.

    Directory of Open Access Journals (Sweden)

    Christine Hellmann

    Full Text Available Understanding interactions between native and invasive plant species in field settings and quantifying the impact of invaders in heterogeneous native ecosystems requires resolving the spatial scale on which these processes take place. Therefore, functional tracers are needed that enable resolving the alterations induced by exotic plant invasion in contrast to natural variation in a spatially explicit way. 15N isoscapes, i.e., spatially referenced representations of stable nitrogen isotopic signatures, have recently provided such a tracer. However, different processes, e.g. water, nitrogen or carbon cycles, may be affected at different spatial scales. Thus multi-isotope studies, by using different functional tracers, can potentially return a more integrated picture of invader impact. This is particularly true when isoscapes are submitted to statistical methods suitable to find homogeneous subgroups in multivariate data such as cluster analysis. Here, we used model-based clustering of spatially explicit foliar δ15N and δ13C isoscapes together with N concentration of a native indicator species, Corema album, to map regions of influence in a Portuguese dune ecosystem invaded by the N2-fixing Acacia longifolia. Cluster analysis identified regions with pronounced alterations in N budget and water use efficiency in the native species, with a more than twofold increase in foliar N, and δ13C and δ15N enrichment of up to 2‰ and 8‰ closer to the invader, respectively. Furthermore, clusters of multiple functional tracers indicated a spatial shift from facilitation through N addition in the proximity of the invader to competition for resources other than N in close contact. Finding homogeneous subgroups in multi-isotope data by means of model-based cluster analysis provided an effective tool for detecting spatial structure in processes affecting plant physiology and performance. The proposed method can give an objective measure of the spatial extent

  12. Differential responses of invasive and native plants to warming with simulated changes in diurnal temperature ranges.

    Science.gov (United States)

    Chen, Bao-Ming; Gao, Yang; Liao, Hui-Xuan; Peng, Shao-Lin

    2017-07-01

    Although many studies have documented the effects of global warming on invasive plants, little is known about whether the effects of warming on plant invasion differ depending on the imposed change in different diurnal temperature ranges (DTR). We tested the impact of warming with DTR change on seed germination and seedling growth of eight species in the family Asteraceae. Four of these are invasive ( Eupatorium catarium , Mikania micrantha , Biodens pilosa var. radiate , Ageratum conyzoides ) in China, and four are native ( Sonchus arvensis , Senecios candens , Pterocypsela indica , Eupatorium fortunei ). Four temperature treatments were set in growth chambers (three warming by 3 °C with different DTRs and control), and experiments were run to mimic wintertime and summertime conditions. The control treatment ( T c ) was set to the mean temperature for the corresponding time of year, and the three warming treatments were symmetric (i.e. equal night-and-day) (DTR sym ), asymmetric warming with increased (DTR inc ) and decreased (DTR dec ) DTR. The warming treatments did not affect seed germination of invasive species under any of the conditions, but DTR sym and DTR inc increased seed germination of natives relative to the control, suggesting that warming may not increase success of these invasive plant species via effects on seed germination of invasive plants relative to native plants. The invasive plants had higher biomass and greater stem allocation than the native ones under all of the warming treatments. Wintertime warming increased the biomass of the invasive and wintertime DTR sym and DTR inc increased that of the native plants, whereas summertime asymmetric warming decreased the biomass of the invasives but not the natives. Therefore, warming may not facilitate invasion of these invasive species due to the suppressive effects of summertime warming (particularly the asymmetric warming) on growth. Compared with DTR sym , DTR dec decreased the biomass of

  13. A comprehensive test of evolutionarily increased competitive ability in a highly invasive plant species

    Science.gov (United States)

    Joshi, Srijana; Gruntman, Michal; Bilton, Mark; Seifan, Merav; Tielbörger, Katja

    2014-01-01

    Background and Aims A common hypothesis to explain plants' invasive success is that release from natural enemies in the introduced range selects for reduced allocation to resistance traits and a subsequent increase in resources available for growth and competitive ability (evolution of increased competitive ability, EICA). However, studies that have investigated this hypothesis have been incomplete as they either did not test for all aspects of competitive ability or did not select appropriate competitors. Methods Here, the prediction of increased competitive ability was examined with the invasive plant Lythrum salicaria (purple loosestrife) in a set of common-garden experiments that addressed these aspects by carefully distinguishing between competitive effect and response of invasive and native plants, and by using both intraspecific and interspecific competition settings with a highly vigorous neighbour, Urtica dioica (stinging nettle), which occurs in both ranges. Key Results While the intraspecific competition results showed no differences in competitive effect or response between native and invasive plants, the interspecific competition experiment revealed greater competitive response and effect of invasive plants in both biomass and seed production. Conclusions The use of both intra- and interspecific competition experiments in this study revealed opposing results. While the first experiment refutes the EICA hypothesis, the second shows strong support for it, suggesting evolutionarily increased competitive ability in invasive populations of L. salicaria. It is suggested that the use of naturally co-occurring heterospecifics, rather than conspecifics, may provide a better evaluation of the possible evolutionary shift towards greater competitive ability. PMID:25301818

  14. A regional assessment of white-tailed deer effects on plant invasion

    Science.gov (United States)

    Mortensen, David A; Smithwick, Erica A H; Kalisz, Susan; McShea, William J; Bourg, Norman A; Parker, John D; Royo, Alejandro A; Abrams, Marc D; Apsley, David K; Blossey, Bernd; Boucher, Douglas H; Caraher, Kai L; DiTommaso, Antonio; Johnson, Sarah E; Masson, Robert; Nuzzo, Victoria A

    2018-01-01

    Abstract Herbivores can profoundly influence plant species assembly, including plant invasion, and resulting community composition. Population increases of native herbivores, e.g. white-tailed deer (Odocoileus virginianus), combined with burgeoning plant invasions raise concerns for native plant diversity and forest regeneration. While individual researchers typically test for the impact of deer on plant invasion at a few sites, the overarching influence of deer on plant invasion across regional scales is unclear. We tested the effects of deer on the abundance and diversity of introduced and native herbaceous and woody plants across 23 white-tailed deer research sites distributed across the east-central and north-eastern USA and representing a wide range of deer densities and invasive plant abundance and identity. Deer access/exclusion or deer population density did not affect introduced plant richness or community-level abundance. Native and total plant species richness, abundance (cover and stem density) and Shannon diversity were lower in deer-access vs. deer-exclusion plots. Among deer-access plots, native species richness, native and total cover, and Shannon diversity (cover) declined as deer density increased. Deer access increased the proportion of introduced species cover (but not of species richness or stem density). As deer density increased, the proportion of introduced species richness, cover and stem density all increased. Because absolute abundance of introduced plants was unaffected by deer, the increase in proportion of introduced plant abundance is likely an indirect effect of deer reducing native cover. Indicator species analysis revealed that deer access favoured three introduced plant species, including Alliaria petiolata and Microstegium vimineum, as well as four native plant species. In contrast, deer exclusion favoured three introduced plant species, including Lonicera japonica and Rosa multiflora, and 15 native plant species. Overall, native

  15. Buffelgrass-Integrated modeling of an invasive plant

    Science.gov (United States)

    Holcombe, Tracy R.

    2011-01-01

    Buffelgrass (Pennisetum ciliare) poses a problem in the deserts of the United States, growing in dense stands and introducing a wildfire risk in an ecosystem not adapted to fire. The Invasive Species Science Branch of the Fort Collins Science Center has worked with many partners to develop a decision support model and a data management system to address the problem. The decision support model evaluates potential strategies for resource use and allocation. The data management system is a portal where users can submit, view, and download buffelgrass data. These tools provide a case study showcasing how the FORT is working to address the urgent issue of invasive species in the United States.

  16. Separating habitat invasibility by alien plants from the actual level of invasion

    Czech Academy of Sciences Publication Activity Database

    Chytrý, M.; Jarošík, Vojtěch; Pyšek, Petr; Hájek, O.; Knollová, I.; Tichý, L.; Danihelka, Jiří

    2008-01-01

    Roč. 89, č. 6 (2008), s. 1541-1553 ISSN 0012-9658 R&D Projects: GA MŠk(CZ) LC06073 Grant - others:ALARM(XE) GOCE-CT-2003-506675 Institutional research plan: CEZ:AV0Z60050516 Keywords : archaeophyte * biological invasions * Central Europe Subject RIV: EF - Botanics Impact factor: 4.874, year: 2008

  17. Plant invasions in the Czech Republic: current state, introduction dynamics, invasive species and invaded habitats

    Czech Academy of Sciences Publication Activity Database

    Pyšek, Petr; Chytrý, M.; Pergl, Jan; Sádlo, Jiří; Wild, Jan

    2012-01-01

    Roč. 84, č. 3 (2012), s. 575-629 ISSN 0032-7786 R&D Projects: GA ČR(CZ) GAP504/11/1028 Institutional research plan: CEZ:AV0Z60050516 Institutional support: RVO:67985939 Keywords : invasive species * invaded habitats * Czech Republic Subject RIV: EF - Botanics Impact factor: 2.833, year: 2012

  18. Co-introduction vs ecological fitting as pathways to the establishment of effective mutualisms during biological invasions.

    Science.gov (United States)

    Le Roux, Johannes J; Hui, Cang; Keet, Jan-Hendrik; Ellis, Allan G

    2017-09-01

    Contents 1354 I. 1354 II. 1355 III. 1357 IV. 1357 V. 1359 1359 References 1359 SUMMARY: Interactions between non-native plants and their mutualists are often disrupted upon introduction to new environments. Using legume-rhizobium mutualistic interactions as an example, we discuss two pathways that can influence symbiotic associations in such situations: co-introduction of coevolved rhizobia; and utilization of, and adaptation to, resident rhizobia, hereafter referred to as 'ecological fitting'. Co-introduction and ecological fitting have distinct implications for successful legume invasions and their impacts. Under ecological fitting, initial impacts may be less severe and will accrue over longer periods as novel symbiotic associations and/or adaptations may require fine-tuning over time. Co-introduction will have more profound impacts that will accrue more rapidly as a result of positive feedbacks between densities of non-native rhizobia and their coevolved host plants, in turn enhancing competition between native and non-native rhizobia. Co-introduction can further impact invasion outcomes by the exchange of genetic material between native and non-native rhizobia, potentially resulting in decreased fitness of native legumes. A better understanding of the roles of these two pathways in the invasion dynamics of non-native legumes is much needed, and we highlight some of the exciting research avenues it presents. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  19. The effects of an invasive alien plant (Chromolaena odorata on large African mammals

    Directory of Open Access Journals (Sweden)

    Lihle Dumalisile

    2017-11-01

    Full Text Available Alien plants have invaded most ecosystem types (terrestrial, fresh water and marine and are responsible for the loss of irreplaceable natural services on which humankind relies. They alter food quantity, quality and accessibility, and may result in declines in native species richness, which may ultimately result in extinction. For an effective management of invasive alien plants, it is important to understand the effects that such plants have on all levels of biodiversity. However, the effects that invasive alien plants, such as the Triffid weed (Chromolaena odorata, have on mammalian biodiversity, especially large mammalian species, are not well-known, although they play major ecological roles in areas such as nutrient cycling. Also, little is known about the recovery of the ecosystem following alien plant removal. This study investigated the effects of C. odorata invasion on large mammalian herbivores in Hluhluwe-iMfolozi Park and whether clearing of this plant helped in rehabilitating the habitat. We used track counts to estimate and compare species richness, diversity and abundance indices for large mammalian species between areas with differing C. odorata invasion durations (ca 2 years, ca 10 years, ca 20 years, areas with differing clearing times (cl < 2 years, cl 3–5 years and an area without any history of C. odorata invasion as a control. The results from this study show that large mammalian species utilised the uninvaded and the cleared areas more than the invaded areas. Species richness, abundance and diversity decreased with increasing invasion duration and cleared areas showed an increasing species richness and abundance. We conclude that this invasive alien plant modifies habitats and their removal does aid in the restoration of the ecosystem.

  20. Investigating Effects of Invasive Species on Plant Community Structure

    Science.gov (United States)

    Franklin, Wilfred

    2008-01-01

    In this article, the author presents a field study project that explores factors influencing forest community structure and lifts the veil off of "plant blindness." This ecological study consists of three laboratories: (1) preliminary field trip to the study site; (2) plant survey; and (3) analyzing plant community structure with descriptive…

  1. Monitoring invasive plants using hand-held GIS technology

    Science.gov (United States)

    Theresa M. Mau-Crimmins; Barron J. Orr

    2005-01-01

    Successful control of invasive species requires a clear picture of the spatial extent of infestations. The latest mapping technology involves coupling global position systems and handheld computers running geographic information systems software in the field. A series of workshops applying this technology to mapping weeds was developed and presented to Weed Management...

  2. Bias and error in understanding plant invasion impacts

    Czech Academy of Sciences Publication Activity Database

    Hulme, P. E.; Pyšek, Petr; Jarošík, Vojtěch; Pergl, Jan; Schaffner, U.; Vila, M.

    2013-01-01

    Roč. 28, č. 4 (2013), s. 212-218 ISSN 0169-5347 R&D Projects: GA ČR(CZ) GAP504/11/1028 Institutional support: RVO:67985939 Keywords : biodiversity * invasions * ecosystem processes Subject RIV: EF - Botanics Impact factor: 15.353, year: 2013

  3. Geographic population structure in an outcrossing plant invasion after centuries of cultivation and recent founding events.

    Science.gov (United States)

    Gaskin, John F; Schwarzländer, Mark; Gibson, Robert D; Simpson, Heather; Marshall, Diane L; Gerber, Esther; Hinz, Hariet

    2018-04-01

    Population structure and genetic diversity of invasions are the result of evolutionary processes such as natural selection, drift and founding events. Some invasions are also molded by specific human activities such as selection for cultivars and intentional introduction of desired phenotypes, which can lead to low genetic diversity in the resulting invasion. We investigated the population structure, diversity and origins of a species with both accidental and intentional introduction histories, as well as long-term selection as a cultivar. Dyer's woad ( Isatis tinctoria ; Brassicaceae) has been used as a dye source for at least eight centuries in Eurasia, was introduced to eastern USA in the 1600s, and is now considered invasive in the western USA. Our analyses of amplified fragment length polymorphisms (AFLPs) from 645 plants from the USA and Eurasia did not find significantly lower gene diversity ( H j ) in the invaded compared to the native range. This suggests that even though the species was under cultivation for many centuries, human selection of plants may not have had a strong influence on diversity in the invasion. We did find significantly lower genetic differentiation ( F st ) in the invasive range but our results still suggested that there are two distinct invasions in the western USA. Our data suggest that these invasions most likely originated from Switzerland, Ukraine and Germany, which correlates with initial biological control agent survey findings. Genetic information on population structure, diversity and origins assists in efforts to control invasive species, and continued combination of ecological and molecular analyses will help bring us closer to sustainable management of plant invasions.

  4. Characterizing pathways of invasion using Sternorryhncha on imported plant material in cargo

    Science.gov (United States)

    Timothy T. Work

    2011-01-01

    Non-indigenous Homoptera, mainly scales, aphids, and mealy bugs, intercepted on plants destined for cultivation represent an elevated risk for the establishment of invasive insects in North America. These insects [grouped as the suborder Sternorrhyncha] are often parthenogenic and are imported on viable host plants.

  5. Estimates of the impacts of invasive alien plants on water flows in ...

    African Journals Online (AJOL)

    The adverse impacts of alien plant invasions on water flows have been a prime motivation for South Africa's Working for Water Programme. The approach used in this study builds on a previous national assessment in 1998 by incorporating factors that limit plant water-use, information from recent research and improved flow ...

  6. Invasive plant architecture alters trophic interactions by changing predator abundance and behavior

    Science.gov (United States)

    Dean E. Pearson

    2009-01-01

    As primary producers, plants are known to influence higher trophic interactions by initiating food chains. However, as architects, plants may bypass consumers to directly affect predators with important but underappreciated trophic ramifications. Invasion of western North American grasslands by the perennial forb, spotted knapweed (Centaurea maculosa...

  7. Impact of mine dumps on transport the invasive plant species to Upper Silesia

    Science.gov (United States)

    Sotkova, N.; Lokajickova, B.; Mec, J.; Svehlakova, H.; Stalmachova, B.

    2017-10-01

    Human activities significantly change the species composition in the area. The main factor of change was the mining industry, which changed the natural conditions on Upper Silesia. The anthropogenic relief of mine dumps are the main centre of alien plant in an industrial landscape. The poster deals with the state of the invasive plant species by the phyto-sociological surveys on Upper Silesia.

  8. Nonnative forest insects and pathogens in the United States: impacts and policy options

    Science.gov (United States)

    Gary M. Lovett; Marissa Weiss; Andrew M. Liebhold; Tom Holmes; Brian Leung; Kathy-Fallon Lambert; David A. Orwig; Faith T. Campbell; Jonathan Rosenthal; Deborah G. McCullough; Radka Wildova; Matthew P. Ayres; Charles D. Canham; David R. Foster; Shannon L. LaDeau; Troy Weldy

    2016-01-01

    We review and synthesize information on invasions of nonnative forest insects and diseases in the United States, including their ecological and economic impacts, pathways of arrival, distribution within the United States, and policy options for reducing future invasions. Nonnative insects have accumulated in United States forests at a rate of ~2.5 per yr over the last...

  9. Distribution of the invasive plant species Heracleum sosnowskyi Manden. in the Komi Republic (Russia).

    Science.gov (United States)

    Chadin, Ivan; Dalke, Igor; Zakhozhiy, Ilya; Malyshev, Ruslan; Madi, Elena; Olga Kuzivanova; Kirillov, Dmitrii; Elsakov, Vladimir

    2017-01-01

    Occurrences of the invasive plant species Heracleum sosnowskyi Manden. in the Komi Republic (northeastern part of European Russia) were recorded and published in the Global Biodiversity Information Facility (GBIF http://www.gbif.org) using the RIVR information system (http://ib.komisc.ru/add/rivr/en). RIVR stands for "Rasprostranenie Invasionnyh Vidov Rastenij" [Occurrence of Invasion Plant Species]. This citizen science project aims at collecting occurrence data about invasive plant species with the help of citizen scientists. Information can be added by any user after a simple registration (concept) process. However, the data published in GBIF are provided only by professional scientists. The total study area is approximately 19,000 km 2 . The GBIF resource contains 10894 Heracleum sosnowskyi occurrence points, each with their geographical coordinates and photographs of the plants in the locus of growth. The preliminary results of species distribution modelling on the territory of European North-East Russia presented.

  10. Linking Native and Invader Traits Explains Native Spider Population Responses to Plant Invasion.

    Directory of Open Access Journals (Sweden)

    Jennifer N Smith

    Full Text Available Theoretically, the functional traits of native species should determine how natives respond to invader-driven changes. To explore this idea, we simulated a large-scale plant invasion using dead spotted knapweed (Centaurea stoebe stems to determine if native spiders' web-building behaviors could explain differences in spider population responses to structural changes arising from C. stoebe invasion. After two years, irregular web-spiders were >30 times more abundant and orb weavers were >23 times more abundant on simulated invasion plots compared to controls. Additionally, irregular web-spiders on simulated invasion plots built webs that were 4.4 times larger and 5.0 times more likely to capture prey, leading to >2-fold increases in recruitment. Orb-weavers showed no differences in web size or prey captures between treatments. Web-spider responses to simulated invasion mimicked patterns following natural invasions, confirming that C. stoebe's architecture is likely the primary attribute driving native spider responses to these invasions. Differences in spider responses were attributable to differences in web construction behaviors relative to historic web substrate constraints. Orb-weavers in this system constructed webs between multiple plants, so they were limited by the overall quantity of native substrates but not by the architecture of individual native plant species. Irregular web-spiders built their webs within individual plants and were greatly constrained by the diminutive architecture of native plant substrates, so they were limited both by quantity and quality of native substrates. Evaluating native species traits in the context of invader-driven change can explain invasion outcomes and help to identify factors limiting native populations.

  11. Facilitation and competition among invasive plants: a field experiment with alligatorweed and water hyacinth.

    Science.gov (United States)

    Wundrow, Emily J; Carrillo, Juli; Gabler, Christopher A; Horn, Katherine C; Siemann, Evan

    2012-01-01

    Ecosystems that are heavily invaded by an exotic species often contain abundant populations of other invasive species. This may reflect shared responses to a common factor, but may also reflect positive interactions among these exotic species. Armand Bayou (Pasadena, TX) is one such ecosystem where multiple species of invasive aquatic plants are common. We used this system to investigate whether presence of one exotic species made subsequent invasions by other exotic species more likely, less likely, or if it had no effect. We performed an experiment in which we selectively removed exotic rooted and/or floating aquatic plant species and tracked subsequent colonization and growth of native and invasive species. This allowed us to quantify how presence or absence of one plant functional group influenced the likelihood of successful invasion by members of the other functional group. We found that presence of alligatorweed (rooted plant) decreased establishment of new water hyacinth (free-floating plant) patches but increased growth of hyacinth in established patches, with an overall net positive effect on success of water hyacinth. Water hyacinth presence had no effect on establishment of alligatorweed but decreased growth of existing alligatorweed patches, with an overall net negative effect on success of alligatorweed. Moreover, observational data showed positive correlations between hyacinth and alligatorweed with hyacinth, on average, more abundant. The negative effect of hyacinth on alligatorweed growth implies competition, not strong mutual facilitation (invasional meltdown), is occurring in this system. Removal of hyacinth may increase alligatorweed invasion through release from competition. However, removal of alligatorweed may have more complex effects on hyacinth patch dynamics because there were strong opposing effects on establishment versus growth. The mix of positive and negative interactions between floating and rooted aquatic plants may influence local

  12. Facilitation and competition among invasive plants: a field experiment with alligatorweed and water hyacinth.

    Directory of Open Access Journals (Sweden)

    Emily J Wundrow

    Full Text Available Ecosystems that are heavily invaded by an exotic species often contain abundant populations of other invasive species. This may reflect shared responses to a common factor, but may also reflect positive interactions among these exotic species. Armand Bayou (Pasadena, TX is one such ecosystem where multiple species of invasive aquatic plants are common. We used this system to investigate whether presence of one exotic species made subsequent invasions by other exotic species more likely, less likely, or if it had no effect. We performed an experiment in which we selectively removed exotic rooted and/or floating aquatic plant species and tracked subsequent colonization and growth of native and invasive species. This allowed us to quantify how presence or absence of one plant functional group influenced the likelihood of successful invasion by members of the other functional group. We found that presence of alligatorweed (rooted plant decreased establishment of new water hyacinth (free-floating plant patches but increased growth of hyacinth in established patches, with an overall net positive effect on success of water hyacinth. Water hyacinth presence had no effect on establishment of alligatorweed but decreased growth of existing alligatorweed patches, with an overall net negative effect on success of alligatorweed. Moreover, observational data showed positive correlations between hyacinth and alligatorweed with hyacinth, on average, more abundant. The negative effect of hyacinth on alligatorweed growth implies competition, not strong mutual facilitation (invasional meltdown, is occurring in this system. Removal of hyacinth may increase alligatorweed invasion through release from competition. However, removal of alligatorweed may have more complex effects on hyacinth patch dynamics because there were strong opposing effects on establishment versus growth. The mix of positive and negative interactions between floating and rooted aquatic plants may

  13. A global organism detection and monitoring system for non-native species

    Science.gov (United States)

    Graham, J.; Newman, G.; Jarnevich, C.; Shory, R.; Stohlgren, T.J.

    2007-01-01

    Harmful invasive non-native species are a significant threat to native species and ecosystems, and the costs associated with non-native species in the United States is estimated at over $120 Billion/year. While some local or regional databases exist for some taxonomic groups, there are no effective geographic databases designed to detect and monitor all species of non-native plants, animals, and pathogens. We developed a web-based solution called the Global Organism Detection and Monitoring (GODM) system to provide real-time data from a broad spectrum of users on the distribution and abundance of non-native species, including attributes of their habitats for predictive spatial modeling of current and potential distributions. The four major subsystems of GODM provide dynamic links between the organism data, web pages, spatial data, and modeling capabilities. The core survey database tables for recording invasive species survey data are organized into three categories: "Where, Who & When, and What." Organisms are identified with Taxonomic Serial Numbers from the Integrated Taxonomic Information System. To allow users to immediately see a map of their data combined with other user's data, a custom geographic information system (GIS) Internet solution was required. The GIS solution provides an unprecedented level of flexibility in database access, allowing users to display maps of invasive species distributions or abundances based on various criteria including taxonomic classification (i.e., phylum or division, order, class, family, genus, species, subspecies, and variety), a specific project, a range of dates, and a range of attributes (percent cover, age, height, sex, weight). This is a significant paradigm shift from "map servers" to true Internet-based GIS solutions. The remainder of the system was created with a mix of commercial products, open source software, and custom software. Custom GIS libraries were created where required for processing large datasets

  14. Effects of Invasive-Plant Management on Nitrogen-Removal Services in Freshwater Tidal Marshes.

    Directory of Open Access Journals (Sweden)

    Mary Alldred

    Full Text Available Establishing relationships between biodiversity and ecosystem function is an ongoing endeavor in contemporary ecosystem and community ecology, with important practical implications for conservation and the maintenance of ecosystem services. Removal of invasive plant species to conserve native diversity is a common management objective in many ecosystems, including wetlands. However, substantial changes in plant community composition have the potential to alter sediment characteristics and ecosystem services, including permanent removal of nitrogen from these systems via microbial denitrification. A balanced assessment of costs associated with keeping and removing invasive plants is needed to manage simultaneously for biodiversity and pollution targets. We monitored small-scale removals of Phragmites australis over four years to determine their effects on potential denitrification rates relative to three untreated Phragmites sites and adjacent sites dominated by native Typha angustifolia. Sediment ammonium increased following the removal of vegetation from treated sites, likely as a result of decreases in both plant uptake and nitrification. Denitrification potentials were lower in removal sites relative to untreated Phragmites sites, a pattern that persisted at least two years following removal as native plant species began to re-colonize treated sites. These results suggest the potential for a trade-off between invasive-plant management and nitrogen-removal services. A balanced assessment of costs associated with keeping versus removing invasive plants is needed to adequately manage simultaneously for biodiversity and pollution targets.

  15. Effects of Invasive-Plant Management on Nitrogen-Removal Services in Freshwater Tidal Marshes.

    Science.gov (United States)

    Alldred, Mary; Baines, Stephen B; Findlay, Stuart

    2016-01-01

    Establishing relationships between biodiversity and ecosystem function is an ongoing endeavor in contemporary ecosystem and community ecology, with important practical implications for conservation and the maintenance of ecosystem services. Removal of invasive plant species to conserve native diversity is a common management objective in many ecosystems, including wetlands. However, substantial changes in plant community composition have the potential to alter sediment characteristics and ecosystem services, including permanent removal of nitrogen from these systems via microbial denitrification. A balanced assessment of costs associated with keeping and removing invasive plants is needed to manage simultaneously for biodiversity and pollution targets. We monitored small-scale removals of Phragmites australis over four years to determine their effects on potential denitrification rates relative to three untreated Phragmites sites and adjacent sites dominated by native Typha angustifolia. Sediment ammonium increased following the removal of vegetation from treated sites, likely as a result of decreases in both plant uptake and nitrification. Denitrification potentials were lower in removal sites relative to untreated Phragmites sites, a pattern that persisted at least two years following removal as native plant species began to re-colonize treated sites. These results suggest the potential for a trade-off between invasive-plant management and nitrogen-removal services. A balanced assessment of costs associated with keeping versus removing invasive plants is needed to adequately manage simultaneously for biodiversity and pollution targets.

  16. An assessment of invasive plant species monitored by the Northern Research Station Forest Inventory and Analysis Program, 2005 through 2010

    Science.gov (United States)

    Cassandra M. Kurtz

    2013-01-01

    Invasive plant species are a worldwide concern due to the high ecological and economic costs associated with their presence. This document describes the plant characteristics and regional distribution of the 50 invasive plant species monitored from 2005 through 2010 on forested Phase 2 (P2) Forest Inventory and Analysis (FIA) plots in the 24 states of the Northern...

  17. Wanted and unwanted nature: Invasive plants and the alien–native dichotomy

    OpenAIRE

    Qvenild, Marte

    2013-01-01

    This thesis explores how plants are perceived and categorised as alien, invasive and native respectively at individual, professional, and political levels. The thesis demonstrates how perceptions of and interactions with plants happen in ways that do not always correspond to the environmental authorities definitions of alienness and nativeness. As alienness and nativeness are concepts that are spatiotemporal in character, the labelling of plants as alien or native often involve value-laden di...

  18. Trait differences between naturalized and invasive plant species independent of residence time and phylogeny.

    Science.gov (United States)

    Gallagher, R V; Randall, R P; Leishman, M R

    2015-04-01

    The ability to predict which alien plants will transition from naturalized to invasive prior to their introduction to novel regions is a key goal for conservation and has the potential to increase the efficacy of weed risk assessment (WRA). However, multiple factors contribute to plant invasion success (e.g., functional traits, range characteristics, residence time, phylogeny), and they all must be taken into account simultaneously in order to identify meaningful correlates of invasion success. We compiled 146 pairs of phylogenetically paired (congeneric) naturalized and invasive plant species in Australia with similar minimum residence times (i.e., time since introduction in years). These pairs were used to test for differences in 5 functional traits (flowering duration, leaf size, maximum height, specific leaf area [SLA], seed mass) and 3 characteristics of species' native ranges (biome occupancy, mean annual temperature, and rainfall breadth) between naturalized and invasive species. Invasive species, on average, had larger SLA, longer flowering periods, and were taller than their congeneric naturalized relatives. Invaders also exhibited greater tolerance for different environmental conditions in the native range, where they occupied more biomes and a wider breadth of rainfall and temperature conditions than naturalized congeners. However, neither seed mass nor leaf size differed between pairs of naturalized and invasive species. A key finding was the role of SLA in distinguishing between naturalized and invasive pairs. Species with high SLA values were typically associated with faster growth rates, more rapid turnover of leaf material, and shorter lifespans than those species with low SLA. This suite of characteristics may contribute to the ability of a species to transition from naturalized to invasive across a wide range of environmental contexts and disturbance regimes. Our findings will help in the refinement of WRA protocols, and we advocate the inclusion

  19. Does responsiveness to arbuscular mycorrhizal fungi depend on plant invasive status?

    Science.gov (United States)

    Reinhart, Kurt O; Lekberg, Ylva; Klironomos, John; Maherali, Hafiz

    2017-08-01

    Differences in the direction and degree to which invasive alien and native plants are influenced by mycorrhizal associations could indicate a general mechanism of plant invasion, but whether or not such differences exist is unclear. Here, we tested whether mycorrhizal responsiveness varies by plant invasive status while controlling for phylogenetic relatedness among plants with two large grassland datasets. Mycorrhizal responsiveness was measured for 68 taxa from the Northern Plains, and data for 95 taxa from the Central Plains were included. Nineteen percent of taxa from the Northern Plains had greater total biomass with mycorrhizas while 61% of taxa from the Central Plains responded positively. For the Northern Plains taxa, measurable effects often depended on the response variable (i.e., total biomass, shoot biomass, and root mass ratio) suggesting varied resource allocation strategies when roots are colonized by arbuscular mycorrhizal fungi. In both datasets, invasive status was nonrandomly distributed on the phylogeny. Invasive taxa were mainly from two clades, that is, Poaceae and Asteraceae families. In contrast, mycorrhizal responsiveness was randomly distributed over the phylogeny for taxa from the Northern Plains, but nonrandomly distributed for taxa from the Central Plains. After controlling for phylogenetic similarity, we found no evidence that invasive taxa responded differently to mycorrhizas than other taxa. Although it is possible that mycorrhizal responsiveness contributes to invasiveness in particular species, we find no evidence that invasiveness in general is associated with the degree of mycorrhizal responsiveness. However, mycorrhizal responsiveness among species grown under common conditions was highly variable, and more work is needed to determine the causes of this variation.

  20. Invasive exotic plant species in Sierra Nevada ecosystems

    Science.gov (United States)

    Carla M. D' Antonio; Eric L. Berlow; Karen L. Haubensak

    2004-01-01

    The Sierra Nevada is a topographically and floristically diverse region of the western United States. While it comprises only a fifth of the total land area of California, half of the native plant species in the state occur within the range. In addition, more than 400 plant species are endemic to the Sierra Nevada and many of these are listed as threatened or have...

  1. Invasion of alien plants in fire-damaged forests at southern boundary of the taiga zone

    Energy Technology Data Exchange (ETDEWEB)

    Khapugin, A.A.; Vargot, E.V.; Chugunov, G.G.; Shugaev, N.I.

    2016-07-01

    Aim of the study: Biological invasions are one of the most important areas of forest research. In this study, we revealed invasibility of fire-damaged forests at the southern boundary of the taiga zone. Area of study: The Mordovia State Nature Reserve (Central Russia). Material and Methods: Altogether, 11 square plots of each 100 ×100 m were established in different types of fire-damaged forests. To test plant invasion outside the established plots, field researches were carried out by route method in fire-damaged area of the Mordovia Reserve. Main Results: Six alien species (Erigeron canadensis, E. annuus, Oenothera biennis, Lactuca serriola, Sambucus racemosa, Viola arvensis) were registered within the established plots in 2011–2014. In addition, two alien invasive plants (Solidago canadensis and Bidens frondosa) were found outside these plots. No differences were detected in invasibility of the tested forest ecosystems. Research highlights: Among the revealed alien species, Erigeron canadensis, Lactuca serriola and Solidago canadensis are the most invasive plants in forest ecosystems. The first one was observed with a high occurrence frequency and abundance in all forest types tested. The second one has not been differed by abundance, but it characterized by a high competition as well as a large biomass and a large number of seeds. Solidago canadensis penetrated to natural forest ecosystem in a short time period due to closest location of its dispersal centers near the boundary of the Mordovia Reserve. These species are the most probable invaders of the forest ecosystems. (Author)

  2. Diversity reduces invasibility in experimental plant communities: the role of plant species

    NARCIS (Netherlands)

    Van Ruijven, J.; De Deyn, G.B.; Berendse, F.

    2003-01-01

    Several studies have presented experimental evidence that diversity reduces invasibility in grassland communities. The interpretation of these results has been disputed recently and it was proposed that sampling effects were responsible for the observed decrease of invasibility with diversity. The

  3. Plant community responses to simultaneous changes in temperature, nitrogen availability, and invasion.

    Directory of Open Access Journals (Sweden)

    Elise S Gornish

    Full Text Available Increasing rates of change in climate have been observed across the planet and have contributed to the ongoing range shifts observed for many species. Although ecologists are now using a variety of approaches to study how much and through what mechanisms increasing temperature and nutrient pollution may influence the invasions inherent in range shifts, accurate predictions are still lacking.In this study, we conducted a factorial experiment, simultaneously manipulating warming, nitrogen addition and introduction of Pityopsis aspera, to determine how range-shifting species affect a plant community. We quantified the resident community using ordination scores, then used structural equation modeling to examine hypotheses related to how plants respond to a network of experimental treatments and environmental variables. Variation in soil pH explained plant community response to nitrogen addition in the absence of invasion. However, in the presence of invasion, the direct effect of nitrogen on the community was negligible and soil moisture was important for explaining nitrogen effects. We did not find effects of warming on the native plant community in the absence of invasion. In the presence of invasion, however, warming had negative effects on functional richness directly and invasion and herbivory explained the overall positive effect of warming on the plant community.This work highlights the variation in the biotic and abiotic factors responsible for explaining independent and collective climate change effects over a short time scale. Future work should consider the complex and non-additive relationships among factors of climate change and invasion in order to capture more ecologically relevant features of our changing environment.

  4. Elevated nitrogen allows the weak invasive plant Galinsoga quadriradiata to become more vigorous with respect to inter-specific competition.

    Science.gov (United States)

    Liu, Gang; Yang, Ying-Bo; Zhu, Zhi-Hong

    2018-02-16

    Elevated nitrogen associated with global change is believed to promote the invasion of many vigorous exotic plants. However, it is unclear how a weak exotic plant will respond to elevated nitrogen in the future. In this study, the competitive outcome of a weak invasive plant (Galinsoga quadriradiata) and two non-invasive plants was detected. The plants were subjected to 3 types of culture (mixed, monoculture or one-plant), 2 levels of nitrogen (ambient or elevated at a rate of 2 g m -2 yr -1 ) and 2 levels of light (65% shade or full sunlight). The results showed that elevated nitrogen significantly promoted the growth of both the weak invader and the non-invasive plants in one-plant pots; however, growth promotion was not observed for the non-invasive species in the mixed culture pots. The presence of G. quadriradiata significantly inhibited the growth of the non-invasive plants, and a decreased negative species interaction was detected as a result of elevated nitrogen. Our results suggest that competitive interactions between G. quadriradiata and the non-invasive plants were altered by elevated nitrogen. It provides exceptional evidence that an initially weak invasive plant can become an aggressive invader through elevated nitrogen deposition.

  5. Size-symmetric competition in a shade-tolerant invasive plant

    DEFF Research Database (Denmark)

    Pan, Xiao-Yun; Weiner, Jacob; Li, Bo

    2013-01-01

    competition need not be size asymmetric, and suggest that tolerance to low light levels involves a reduction in phenotypic plasticity. Responses of the invasive A. philoxeroides to crowding may be an example of an invasive plant’s success in establishing dense stands of closely related individuals......, a shade‐tolerant invasive species. Stem fragments of A. philoxeroides were grown at either low or high densities (6 vs. 24 plants per pot) under three light levels (10%, 34%, and 100% full sun). After 8 weeks, survival was 31% lower in pots with a higher initial density. Both high density and low light...... levels reduced plant size substantially. Mean plant biomass ranged from 0.23 g in high‐density and low‐light pots to 4.41 g in low‐density and high‐light pots. There were no strong or significant effects of density or light level on size inequality of survivors. Most of the variation in allocation...

  6. Invasive alien plants in protected areas within city borders, LODZ (poland)

    International Nuclear Information System (INIS)

    Anna, B.; Grzegorz, W.J.; Krason, K.

    2017-01-01

    The aim of the study was to present the occurrence of invasive alien plant species in two forest reserves: "Las Lagiewnicki"and "Polesie Konstantynowskie", located within the city of Lodz (Central Poland). Currently, five vascular plants (Impatiens parviflora, Juncus tenuis, Padus serotina, Quercus rubra, Robinia pseudoacacia) and one moss (Orthodontium lineare) considered as invasive were found in the studied reserves. Invasive plant species accounted for a small percentage of the flora in the studied reserves, and their sites were mainly concentrated in areas transformed by human activity. The most common species were Impatiens parviflora and Padus serotina. Due to the location of the reserves within city borders and the proven negative effect of the found species on ecological systems, their sites should be monitored. (author)

  7. Living with Invasive Plants in the Anthropocene: The Importance of Understanding Practice and Experience

    Directory of Open Access Journals (Sweden)

    Lesley Head

    2015-01-01

    Full Text Available The role of humans in facilitating the rapid spread of plants at a scale that is considered invasive is one manifestation of the Anthropocene, now framed as a geological period in which humans are the dominant force in landscape transformation. Invasive plant management faces intensified challenges, and can no longer be viewed in terms of ′eradication′ or ′restoration of original landscapes′. In this perspectives piece, we focus on the practice and experience of people engaged in invasive plant management, using examples from Australia and Canada. We show how managers 1 face several pragmatic trade-offs; 2 must reconcile diverse views, even within stakeholder groups; 3 must balance competing temporal scales; 4 encounter tensions with policy; and 5 face critical and under-acknowledged labour challenges. These themes show the variety of considerations based on which invasive plant managers make complex decisions about when, where, and how to intervene. Their widespread pragmatic acceptance of small, situated gains (as well as losses combines with impressive long-term commitments to the task of invasives management. We suggest that the actual practice of weed management challenges those academic perspectives that still aspire to attain pristine nature.

  8. Using composting for control seed germination of invasive plant (water hyacinth) in Extremadura (Spain)

    Science.gov (United States)

    Labrador, Juana; Gordillo, Judit; Ruiz, Trinidad; Albano, Eva; Moreno, Marta M.

    2016-04-01

    The biotransformation of the invasive water hyacinth (Eichhornia crassipes) by composting has been showed as a viable alternative to offset the economic cost of eliminating an invasive plant giving a value to the by-product; however, as result of the propagative plant capacity, it was necessary to check if the composting process could eliminate the germination seed rate. Despite the high temperatures and the biochemical biotransformation processes of the composting components, in the case of seed water hyacinth, with a recovery rate of 100%, damage was observed in some parts of the seed anatomy such as in the outer teguments; however, other parts of the seed coat and the endosperm maintained their integrity. A microscopic analysis revealed that the embryo was noticeable and this was supported by the rate of seed germination observed (3.5 ± 0.96%). The results indicate that the use of water hyacinth for compost production is not completely safe from an environmental perspective. Keywords: Eichhornia crassipes, water hyacinth, invasive plant, seed anatomy, seed germination rate, compost. References: Ruiz T., Martín de Rodrigo E., Lorenzo G., Albano E., Morán R., Sánchez J.M. 2008. The Water Hyacinth, Eichhornia crassipes: an invasive plant in the Guadiana River Basin (Spain). Aquatic Invasions Volume 3, Issue 1:42-53.

  9. Using Remote Sensing Mapping and Growth Response to Environmental Variability to Aide Aquatic Invasive Plant Management

    Science.gov (United States)

    Bubenheim, David L.; Schlick, Greg; Genovese, Vanessa; Wilson, Kenneth D.

    2018-01-01

    Management of aquatic weeds in complex watersheds and river systems present many challenges to assessment, planning and implementation of management practices for floating and submerged aquatic invasive plants. The Delta Region Areawide Aquatic Weed Project (DRAAWP), a USDA sponsored area-wide project, is working to enhance planning, decision-making and operational efficiency in the California Sacramento-San Joaquin Delta. Satellite and airborne remote sensing are used map (area coverage and biomass density), direct operations, and assess management impacts on plant communities. Archived satellite records enable review of results following previous climate and management events and aide in developing long-term strategies. Examples of remote sensing aiding effectiveness of aquatic weed management will be discussed as well as areas for potential technological improvement. Modeling at local and watershed scales using the SWAT modeling tool provides insight into land-use effects on water quality (described by Zhang in same Symposium). Controlled environment growth studies have been conducted to quantify the growth response of invasive aquatic plants to water quality and other environmental factors. Environmental variability occurs across a range of time scales from long-term climate and seasonal trends to short-term water flow mediated variations. Response time for invasive species response are examined at time scales of weeks, day, and hours using a combination of study duration and growth assessment techniques to assess water quality, temperature (air and water), nitrogen, phosphorus, and light effects. These provide response parameters for plant growth models in response to the variation and interact with management and economic models associated with aquatic weed management. Plant growth models are to be informed by remote sensing and applied spatially across the Delta to balance location and type of aquatic plant, growth response to altered environments and

  10. Novel chemistry of invasive plants: exotic species have more unique metabolomic profiles than native congeners.

    Science.gov (United States)

    Macel, Mirka; de Vos, Ric C H; Jansen, Jeroen J; van der Putten, Wim H; van Dam, Nicole M

    2014-07-01

    It is often assumed that exotic plants can become invasive when they possess novel secondary chemistry compared with native plants in the introduced range. Using untargeted metabolomic fingerprinting, we compared a broad range of metabolites of six successful exotic plant species and their native congeners of the family Asteraceae. Our results showed that plant chemistry is highly species-specific and diverse among both exotic and native species. Nonetheless, the exotic species had on average a higher total number of metabolites and more species-unique metabolites compared with their native congeners. Herbivory led to an overall increase in metabolites in all plant species. Generalist herbivore performance was lower on most of the exotic species compared with the native species. We conclude that high chemical diversity and large phytochemical uniqueness of the exotic species could be indicative of biological invasion potential.

  11. Resource competition in plant invasions: emerging patterns and research needs

    Czech Academy of Sciences Publication Activity Database

    Gioria, Margherita; Osborne, B. A.

    2014-01-01

    Roč. 5, č. 501 (2014), s. 1-21 ISSN 1664-462X Institutional support: RVO:67985939 Keywords : plant invoasions * resource competition * dominance Subject RIV: EF - Botanics Impact factor: 3.948, year: 2014

  12. Danger to biodiversity of High Tatras by spread of invasive plant species

    International Nuclear Information System (INIS)

    Strba, P.; Gogolakova, A.

    2010-01-01

    The aim of our work was to analyze the current status of invasive plant species - their generic representation of a current extension (horizontal and vertical extension). We have been working method inventory of species richness. Site was recorded on a tourist map and a GPS (Garmin). Populations of invasive plants are studied localities mostly small (a few individuals to hundreds of individuals), but at the high anthropogenic impacts (construction activity, excessive tourist traffic), by synantropization of habitats and concurrently with the impacts of climate change here can create important focal point of the country and pose a serious threat to biodiversity is very valuable ecosystems.

  13. Predicting the presence and cover of management relevant invasive plant species on protected areas.

    Science.gov (United States)

    Iacona, Gwenllian; Price, Franklin D; Armsworth, Paul R

    2016-01-15

    Invasive species are a management concern on protected areas worldwide. Conservation managers need to predict infestations of invasive plants they aim to treat if they want to plan for long term management. Many studies predict the presence of invasive species, but predictions of cover are more relevant for management. Here we examined how predictors of invasive plant presence and cover differ across species that vary in their management priority. To do so, we used data on management effort and cover of invasive plant species on central Florida protected areas. Using a zero-inflated multiple regression framework, we showed that protected area features can predict the presence and cover of the focal species but the same features rarely explain both. There were several predictors of either presence or cover that were important across multiple species. Protected areas with three days of frost per year or fewer were more likely to have occurrences of four of the six focal species. When invasive plants were present, their proportional cover was greater on small preserves for all species, and varied with surrounding household density for three species. None of the predictive features were clearly related to whether species were prioritized for management or not. Our results suggest that predictors of cover and presence can differ both within and across species but do not covary with management priority. We conclude that conservation managers need to select predictors of invasion with care as species identity can determine the relationship between predictors of presence and the more management relevant predictors of cover. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Belowground advantages in construction cost facilitate a cryptic plant invasion.

    Science.gov (United States)

    Caplan, Joshua S; Wheaton, Christine N; Mozdzer, Thomas J

    2014-04-30

    The energetic cost of plant organ construction is a functional trait that is useful for understanding carbon investment during growth (e.g. the resource acquisition vs. tissue longevity tradeoff), as well as in response to global change factors like elevated CO2 and N. Despite the enormous importance of roots and rhizomes in acquiring soil resources and responding to global change, construction costs have been studied almost exclusively in leaves. We sought to determine how construction costs of aboveground and belowground organs differed between native and introduced lineages of a geographically widely dispersed wetland plant species (Phragmites australis) under varying levels of CO2 and N. We grew plants under ambient and elevated atmospheric CO2, as well as under two levels of soil nitrogen. We determined construction costs for leaves, stems, rhizomes and roots, as well as for whole plants. Across all treatment conditions, the introduced lineage of Phragmites had a 4.3 % lower mean rhizome construction cost than the native. Whole-plant construction costs were also smaller for the introduced lineage, with the largest difference in sample means (3.3 %) occurring under ambient conditions. In having lower rhizome and plant-scale construction costs, the introduced lineage can recoup its investment in tissue construction more quickly, enabling it to generate additional biomass with the same energetic investment. Our results suggest that introduced Phragmites has had an advantageous tissue investment strategy under historic CO2 and N levels, which has facilitated key rhizome processes, such as clonal spread. We recommend that construction costs for multiple organ types be included in future studies of plant carbon economy, especially those investigating global change. Published by Oxford University Press on behalf of the Annals of Botany Company.

  15. Arbuscular mycorrhizal assemblages in native plant roots change in the presence of invasive exotic grasses

    Science.gov (United States)

    Hawkes, C.V.; Belnap, J.; D'Antonio, C.; Firestone, M.K.

    2006-01-01

    Plant invasions have the potential to significantly alter soil microbial communities, given their often considerable aboveground effects. We examined how plant invasions altered the arbuscular mycorrhizal fungi of native plant roots in a grassland site in California and one in Utah. In the California site, we used experimentally created plant communities composed of exotic (Avena barbata, Bromus hordeaceus) and native (Nassella pulchra, Lupinus bicolor) monocultures and mixtures. In the Utah semi-arid grassland, we took advantage of invasion by Bromus tectorum into long-term plots dominated by either of two native grasses, Hilaria jamesii or Stipa hymenoides. Arbuscular mycorrhizal fungi colonizing roots were characterized with PCR amplification of the ITS region, cloning, and sequencing. We saw a significant effect of the presence of exotic grasses on the diversity of mycorrhizal fungi colonizing native plant roots. In the three native grasses, richness of mycorrhizal fungi decreased; in the native forb at the California site, the number of fungal RFLP patterns increased in the presence of exotics. The exotic grasses also caused the composition of the mycorrhizal community in native roots to shift dramatically both in California, with turnover of Glomus spp., and Utah, with replacement of Glomus spp. by apparently non-mycorrhizal fungi. Invading plants may be able to influence the network of mycorrhizal fungi in soil that is available to natives through either earlier root activity or differential carbon provision compared to natives. Alteration of the soil microbial community by plant invasion can provide a mechanism for both successful invasion and the resulting effects of invaders on the ecosystem. ?? Springer 2006.

  16. Estimating suitable environments for invasive plant species across large landscapes: A remote sensing strategy using Landsat 7 ETM+

    Science.gov (United States)

    The key to reducing ecological and economic damage caused by invasive plant species is to locate and eradicate new invasions before they threaten native biodiversity and ecological processes. We used Landsat Enhanced Thematic Mapper Plus imagery to estimate suitable environments for four invasive pl...

  17. Public Perception of Invasive Plant Species: Assessing the Impact of Workshop Activities to Promote Young Students' Awareness

    Science.gov (United States)

    Schreck Reis, Catarina; Marchante, Helia; Freitas, Helena; Marchante, Elizabete

    2013-01-01

    Invasive species are one of the main threats to biodiversity worldwide. Even though they are identified and recognized as such by the Portuguese law, the majority of the population is not yet aware of this problem. Aiming to increase awareness about biological invasions among young students, a workshop on Invasive Plant Species was organized at…

  18. Belowground interactions with aboveground consequences: Invasive earthworms and arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Paudel, Shishir; Longcore, Travis; MacDonald, Beau; McCormick, Melissa K; Szlavecz, Katalin; Wilson, Gail W T; Loss, Scot R

    2016-03-01

    A mounting body of research suggests that invasive nonnative earthworms substantially alter microbial communities, including arbuscular mycorrhizal fungi (AMF). These changes to AMF can cascade to affect plant communities and vertebrate populations. Despite these research advances, relatively little is known about (1) the mechanisms behind earthworms' effects on AMF and (2) the factors that determine the outcomes of earthworm-AMF interactions (i.e., whether AMF abundance is increased or decreased and subsequent effects on plants). We predict that AMF-mediated effects of nonnative earthworms on ecosystems are nearly universal because (1) AMF are important components of most terrestrial ecosystems, (2) nonnative earthworms have become established in nearly every type of terrestrial ecosystem, and (3) nonnative earthworms, due to their burrowing and feeding behavior, greatly affect AMF with potentially profound concomitant effects on plant communities. We highlight the multiple direct and indirect effects of nonnative earthworms on plants and review what is currently known about the interaction between earthworms and AMF. We also illustrate how the effects of nonnative earthworms on plant-AMF mutualisms can alter the structure and stability of aboveground plant communities, as well as the vertebrate communities relying on these habitats. Integrative studies that assess the interactive effects of earthworms and AMF can provide new insights into the role that belowground ecosystem engineers play in altering aboveground ecological processes. Understanding these processes may improve our ability to predict the structure of plant and animal communities in earthworm-invaded regions and to develop management strategies that limit the numerous undesired impacts of earthworms.

  19. Global warming increases the interspecific competitiveness of the invasive plant alligator weed, Alternanthera philoxeroides.

    Science.gov (United States)

    Wu, Hao; Ismail, Mohannad; Ding, Jianqing

    2017-01-01

    Global warming could accelerate the spread of invasive species to higher latitudes and intensify their effects on native species. Here, we report results of two years of field surveys along a latitudinal gradient (21°N to 31°N) in southern China, to determine the species structure of the invasive plant Alternanthera philoxeroides community. We also performed a replacement series experiment (mono and mixed) to evaluate the effects of elevated temperature on the competitiveness of A. philoxeroides with the native co-occurring species Digitaria sanguinalis. In the field survey, we found that the dominance of A. philoxeroides increased with increasing of latitude gradient while cover of D. sanguinalis decreased. In monospecific plantings, artificial warming reduced the length of D. sanguinalis roots. In mixed plantings, warming reduced both A. philoxeroides abundance and D. sanguinalis stem length when A. philoxeroides was more prevalent in the planting. Warming also significantly reduced D. sanguinalis biomass, but increased that of A. philoxeroides. In addition, elevated temperatures significantly reduced the relative yield (RY) of D. sanguinalis, particularly when A. philoxeroides was planted in higher proportion in the plot. These results suggest that the invasiveness of A. philoxeroides increased with increasing latitude, and that warming may increase the effectiveness of its interspecific competition with D. sanguinalis. Hence, under global warming conditions, the harm to native species from A. philoxeroides would increase at higher latitudes. Our findings are critical for predicting the invasiveness of alien species under climate change. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. A comprehensive test of evolutionarily increased competitive ability in a highly invasive plant species.

    Science.gov (United States)

    Joshi, Srijana; Gruntman, Michal; Bilton, Mark; Seifan, Merav; Tielbörger, Katja

    2014-12-01

    A common hypothesis to explain plants' invasive success is that release from natural enemies in the introduced range selects for reduced allocation to resistance traits and a subsequent increase in resources available for growth and competitive ability (evolution of increased competitive ability, EICA). However, studies that have investigated this hypothesis have been incomplete as they either did not test for all aspects of competitive ability or did not select appropriate competitors. Here, the prediction of increased competitive ability was examined with the invasive plant Lythrum salicaria (purple loosestrife) in a set of common-garden experiments that addressed these aspects by carefully distinguishing between competitive effect and response of invasive and native plants, and by using both intraspecific and interspecific competition settings with a highly vigorous neighbour, Urtica dioica (stinging nettle), which occurs in both ranges. While the intraspecific competition results showed no differences in competitive effect or response between native and invasive plants, the interspecific competition experiment revealed greater competitive response and effect of invasive plants in both biomass and seed production. The use of both intra- and interspecific competition experiments in this study revealed opposing results. While the first experiment refutes the EICA hypothesis, the second shows strong support for it, suggesting evolutionarily increased competitive ability in invasive populations of L. salicaria. It is suggested that the use of naturally co-occurring heterospecifics, rather than conspecifics, may provide a better evaluation of the possible evolutionary shift towards greater competitive ability. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. [Allelopathic interactions between invasive plant Solidago canadensis and native plant Phragmites australis].

    Science.gov (United States)

    Li, Yu-Zhe; Fan, Jiang-Wen; Yin, Xin; Yang, En-Yi; Wei, Wei; Tian, Zhi-Hui; Da, Liang-Jun

    2011-05-01

    Taking the seeds of invasive plant Solidago canadensis and native plant Phragmites australis from their mono- and co-dominant communities as allelopathic acceptors, this paper analyzed the differences in the seed germination rate and sprout length after treated with five level (12.5, 25, 50, 100, and 200 mg x mL(-1)) S. canadensis and P. australis extracts, aimed to understand the allelopathic interactions between the two species. The 1000-grain weight and seed germination rate under distilled water treatment of the two species in co-dominated community were greater than those in mono-dominant community. Low level (12.5 and 25 mg x mL(-1)) S. canadensi extracts slightly promoted the seed germination rates of S. canadensis in both mono- and co-dominant communities, but high level (50, 100, and 200 mg x mL(-1)) S. canadensi extracts had strong inhibition effect, especially for the S. canadensis in co-dominated community. No significant patterns were observed about the effects of P. australis extract on S. canadensis seed germination. The sprout length of S. canadensis seeds in both mono- and co-dominant communities decreased with increasing level of S. canadensis extract, but decreased in a fluctuation way with increasing level of P. australis extract. After treated with the extracts of P. australis or S. canadensis, the seed germination rate of P. australis in mono-dominant community was significantly greater than that in co-dominant community (P < 0.05), but there was no significant difference between these two extracts.

  2. Phytotoxic property of the invasive plant Tithonia diversifolia and a phytotoxic substance.

    Science.gov (United States)

    Suzuki, Masahiko; Iwasaki, Arihiro; Suenaga, Kiyotake; Kato-Noguchi, Hisashi

    2017-06-01

    Tithonia diversifolia (Hermsl.) A. Gray is a perennial invasive plant and spreads quickly in the invasive areas. The extracts of T. diversifolia were found to be toxic to several crop plant species such as rice, maize, sorghum, lettuce and cowpea, and several putative allelopathic substances were identified. However, there is limited information available for the effects of T. diversifolia on wild plants including weed plant species. We investigated the allelopathic potential of T. diversifolia extracts on weed plants, and searched for phytotoxic substances with allelopathic activity. An aqueous methanol extract of T. diversifolia leaves inhibited the growth of weed plants, Lolium multiflorum Lam., Phleum pretense L., Echinochloa crus-galli (L.) Beauv. The extract was then purified by several chromatographic runs and a phytotoxic substance with allelopathic activity was isolated and identified by spectral analysis as tagitinin C. The substance inhibited the growth of Lolium multiflorum, Phleum pratense and Echinochloa crus-galli at concentrations greater than 0.1 - 0.3 mM. The present results suggest that T. diversifolia may possess allelopathic potential on weed plants and tagitinin C may be responsible for the allelopathic effects of T. diversifolia. The allelopathic potential of T. diversifolia may contribute to its invasive characteristics.

  3. Field Spectroscopy in the VNIR-SWIR Region to Discriminate between Mediterranean Native Plants and Exotic-Invasive Shrubs Based on Leaf Tannin Content

    Directory of Open Access Journals (Sweden)

    Jan Rudolf Karl Lehmann

    2015-01-01

    Full Text Available The invasive shrub, Acacia longifolia, native to southeastern Australia, has a negative impact on vegetation and ecosystem functioning in Portuguese dune ecosystems. In order to spectrally discriminate A. longifolia from other non-native and native species, we developed a classification model based on leaf reflectance spectra (350–2500 nm and condensed leaf tannin content. High variation of leaf tannin content is common for Mediterranean shrub and tree species, in particular between N-fixing and non-N-fixing species, as well as within the genus, Acacia. However, variation in leaf tannin content has not been studied in coastal dune ecosystems in southwest Portugal. We hypothesized that condensed tannin concentration varies significantly across species, further allowing for distinguishing invasive, nitrogen-fixing A. longifolia from other vegetation based on leaf spectral reflectance data. Spectral field measurements were carried out using an ASD FieldSpec FR spectroradiometer attached to an ASD leaf clip in order to collect 750 in situ leaf reflectance spectra of seven frequent plant species at three study sites in southwest Portugal. We applied partial least squares (PLS regression to predict the obtained leaf reflectance spectra of A. longifolia individuals to their corresponding tannin concentration. A. longifolia had the lowest tannin concentration of all investigated species. Four wavelength regions (675–710 nm, 1060–1170 nm, 1360–1450 nm and 1630–1740 nm were identified as being highly correlated with tannin concentration. A spectra-based classification model of the different plant species was calculated using a principal component analysis-linear discriminant analysis (PCA-LDA. The best prediction of A. longifolia was achieved by using wavelength regions between 1360–1450 nm and 1630–1740 nm, resulting in a user’s accuracy of 98.9%. In comparison, selecting the entire wavelength range, the best user accuracy only reached 86

  4. Strategies for preventing invasive plant outbreaks after prescribed fire in ponderosa pine forest

    Science.gov (United States)

    Symstad, Amy J.; Newton, Wesley E.; Swanson, Daniel J.

    2014-01-01

    Land managers use prescribed fire to return a vital process to fire-adapted ecosystems, restore forest structure from a state altered by long-term fire suppression, and reduce wildfire intensity. However, fire often produces favorable conditions for invasive plant species, particularly if it is intense enough to reveal bare mineral soil and open previously closed canopies. Understanding the environmental or fire characteristics that explain post-fire invasive plant abundance would aid managers in efficiently finding and quickly responding to fire-caused infestations. To that end, we used an information-theoretic model-selection approach to assess the relative importance of abiotic environmental characteristics (topoedaphic position, distance from roads), pre-and post-fire biotic environmental characteristics (forest structure, understory vegetation, fuel load), and prescribed fire severity (measured in four different ways) in explaining invasive plant cover in ponderosa pine forest in South Dakota’s Black Hills. Environmental characteristics (distance from roads and post-fire forest structure) alone provided the most explanation of variation (26%) in post-fire cover of Verbascum thapsus (common mullein), but a combination of surface fire severity and environmental characteristics (pre-fire forest structure and distance from roads) explained 36–39% of the variation in post-fire cover of Cirsium arvense (Canada thistle) and all invasives together. For four species and all invasives together, their pre-fire cover explained more variation (26–82%) in post-fire cover than environmental and fire characteristics did, suggesting one strategy for reducing post-fire invasive outbreaks may be to find and control invasives before the fire. Finding them may be difficult, however, since pre-fire environmental characteristics explained only 20% of variation in pre-fire total invasive cover, and less for individual species. Thus, moderating fire intensity or targeting areas

  5. The identification and remote detection of alien invasive plants in ...

    African Journals Online (AJOL)

    Kabir Peerbhay

    remote sensing techniques offer a synoptic rapid approach for detecting and mapping weeds ... plant substrates, soil properties, the microclimate, water relations, density and height of .... Additionally, a precise weed detection system ..... complexities when detecting IAP species for real-time monitoring and decision making.

  6. Non-invasive plant growth measurements for detection of blue-light dose response of stem elongation in Chrysanthemum morifolium

    DEFF Research Database (Denmark)

    Kjær, Katrine Heinsvig

    2012-01-01

    . In the present study a non-invasive plant growth sensor (PlantEye, Phenospex B.V, Heerlen, NL) was tested in analysing changes in diurnal stem elongation patterns and plant height in response to the spectral quality of the light environment. Plants were grown in four different LED supplemental lighting...... treatments with 0%, 12.5%, 18.5% and 22.5% blue light under greenhouse conditions in winter (18 h day/4 h night). The non-invasive measurements were carried out automatically every four hour with three repetitions, and supported by manual measurements of plant height every third day. A strong linear relation...... between the non-invasive measurements and manual measurements of plant height was achieved, and a blue-light dose-response showing a decrease in plant height in relation to an increase in blue light was demonstrated. However, the non-invasive plant growth sensor was not able to distinguish between diurnal...

  7. Evidence, perceptions, and trade-offs associated with invasive alien plant control in the Table Mountain National Park, South Africa

    CSIR Research Space (South Africa)

    Van Wilgen, B

    2012-01-01

    Full Text Available citizens regard the trees as attractive and ecologically beneficial, and for these reasons the alien plant control programs have been controversial. I briefly outline the legal obligations to deal with invasive alien plants, the history of control...

  8. Application of the EDYS Model to Evaluate Control Methods for Invasive Plants at Yakima Training Center, Washington

    National Research Council Canada - National Science Library

    Hunter, Rachael G; Mata-Gonzalez, Ricardo; McLendon, Terry

    2004-01-01

    .... Non-indigenous invasive plants can also reduce and destroy forage for livestock and wildlife, displace native plant species, increase fire frequency, reduce recreational opportunities, and can poison domestic animals...

  9. Allelopathy and resource competition: the effects of Phragmites australis invasion in plant communities.

    Science.gov (United States)

    Uddin, Md Nazim; Robinson, Randall William

    2017-12-01

    Phragmites australis, a ubiquitous wetland plant, has been considered one of the most invasive species in the world. Allelopathy appears to be one of the invasion mechanisms, however, the effects could be masked by resource competition among target plants. The difficulty of distinguishing allelopathy from resource competition among plants has hindered investigations of the role of phytotoxic allelochemicals in plant communities. This has been addressed via experiments conducted in both the greenhouse and laboratory by growing associated plants, Melaleuca ericifolia, Rumex conglomeratus, and model plant, Lactuca sativa at varying densities with the allelopathic plant, P. australis, its litter and leachate of P. australis litter. This study investigated the potential interacting influences of allelopathy and resource competition on plant growth-density relationships. In greenhouse, the root exudates mediated effects showed the strongest growth inhibition of M. ericifolia at high density whereas litter mediated results revealed increased growth at medium density treatments compared to low and high density. Again, laboratory experiments related to seed germination and seedling growth of L. sativa and R. conglomeratus exhibited phytotoxicity decreased showing positive growth as plant density increased and vice versa. Overall, the differential effects were observed among experiments but maximum individual plant biomass and some other positive effects on plant traits such as root and shoot length, chlorophyll content occurred at an intermediate density. This was attributed to the sharing of the available phytotoxin among plants at high densities which is compatible to density-dependent phytotoxicity model. The results demonstrated that plant-plant interference is the combined effect of allelopathy and resource competition with many other factors but this experimental design, target-neighbor mixed-culture in combination of plant grown at varying densities with varying

  10. High-density native-range species affects the invasive plant Chromolaena odorata more strongly than species from its invasive range.

    Science.gov (United States)

    Zheng, Yulong; Liao, Zhiyong

    2017-11-22

    Invasive plant species often form dense mono-dominant stands in areas they have invaded, while having only sparse distribution in their native ranges, and the reasons behind this phenomenon are a key point of research in invasive species biology. Differences in species composition between native and invasive ranges may contribute to the difference in distribution status. In this study, we found that the high-density condition had a more negative effect on C. odorata than the low-density condition when co-grown with neighbor plants from its native range in Mexico, while this pattern was not in evidence when it was grown with neighbors from its invasive range in China. Different competitive ability and coevolutionary history with C. odorata between native-range neighbors and invasive-range neighbors may lead to the inconsistent patterns.

  11. Feral goats in the Hawaiian Islands: understanding the behavioral ecology of nonnative ungulates with GPS and remote sensing technology

    Science.gov (United States)

    Mark Chynoweth; Creighton M. Litton; Christopher A. Lepczyk; Susan Cordell

    2010-01-01

    Nonnative feral ungulates have both direct and indirect impacts on native ecosystems. Hawai`i is particularly susceptible to biological invasions, as the islands have evolved in extreme geographic isolation. In this paper we explore the ecological impacts of nonnative feral goats (Capra hircus) in the Hawaiian Islands, including both the current...

  12. Non-native grass removal and shade increase soil moisture and seedling performance during Hawaiian dry forest restoration

    Science.gov (United States)

    Jared M. Thaxton; Susan Cordell; Robert J. Cabin; Darren R. Sandquist

    2012-01-01

    Invasive non-native species can create especially problematic restoration barriers in subtropical and tropical dry forests. Native dry forests in Hawaii presently cover less than 10% of their original area. Many sites that historically supported dry forest are now completely dominated by non-native species, particularly grasses. Within a grass-dominated site in leeward...

  13. Alien plant invasions--incorporating emerging invaders in regional prioritization: a pragmatic approach for Southern Africa.

    Science.gov (United States)

    Mgidi, Theresa N; Le Maitre, David C; Schonegevel, Lucille; Nel, Jeanne L; Rouget, Mathieu; Richardson, David M

    2007-07-01

    Plant invasions are a serious threat to natural and semi-natural ecosystems worldwide. Most management-orientated research on invasions focuses on invaders that are already widespread and often have major impacts. This paper deals with "emerging" invaders-those alien species with the potential to become important problems without timely intervention. A climate matching procedure was developed to define areas of South Africa, Lesotho and Swaziland that could be invaded by 28 plant species that had previously been classified as emerging invaders. Information on the location of populations of these species in the study area was combined with information on their distributions (as native or alien) in parts of Australia and the United States of America. These two countries had the best available distribution data for this study. They also share many invasive alien plant species with South Africa. Climatic data obtained for weather stations near points of known occurrence in these countries were used to define the climatically suitable areas for each species in the study area. Almost 80% of the remaining natural environment in southern Africa was found to be vulnerable to invasion by at least one of these species, 50% by six or more and 24% by 16 or more species. The most vulnerable areas are the highveld grasslands and the eastern escarpment. The emerging invaders with the greatest potential range included Acacia podalyriifolia and Cortaderia selloana. The globally important invaders Ulex europaeus and Lythrum salicaria had a more limited invasion potential but could still become major invaders. There was no relationship between the extent of the climatically suitable areas for the different species and an expert ranking of their invasion potential, emphasising the uncertainties inherent in making expert assessments based on very little information. The methods used in this analysis establish a protocol for future modelling exercises to assess the invasion potential of

  14. Acceleration of exotic plant invasion in a forested ecosystem by a generalist herbivore.

    Science.gov (United States)

    Eschtruth, Anne K; Battles, John J

    2009-04-01

    The successful invasion of exotic plants is often attributed to the absence of coevolved enemies in the introduced range (i.e., the enemy release hypothesis). Nevertheless, several components of this hypothesis, including the role of generalist herbivores, remain relatively unexplored. We used repeated censuses of exclosures and paired controls to investigate the role of a generalist herbivore, white-tailed deer (Odocoileus virginianus), in the invasion of 3 exotic plant species (Microstegium vimineum, Alliaria petiolata, and Berberis thunbergii) in eastern hemlock (Tsuga canadensis) forests in New Jersey and Pennsylvania (U.S.A.). This work was conducted in 10 eastern hemlock (T. canadensis) forests that spanned gradients in deer density and in the severity of canopy disturbance caused by an introduced insect pest, the hemlock woolly adelgid (Adelges tsugae). We used maximum likelihood estimation and information theoretics to quantify the strength of evidence for alternative models of the influence of deer density and its interaction with the severity of canopy disturbance on exotic plant abundance. Our results were consistent with the enemy release hypothesis in that exotic plants gained a competitive advantage in the presence of generalist herbivores in the introduced range. The abundance of all 3 exotic plants increased significantly more in the control plots than in the paired exclosures. For all species, the inclusion of canopy disturbance parameters resulted in models with substantially greater support than the deer density only models. Our results suggest that white-tailed deer herbivory can accelerate the invasion of exotic plants and that canopy disturbance can interact with herbivory to magnify the impact. In addition, our results provide compelling evidence of nonlinear relationships between deer density and the impact of herbivory on exotic species abundance. These findings highlight the important role of herbivore density in determining impacts on

  15. Using soil seed banks to assess temporal patterns of genetic variation in invasive plant populations

    OpenAIRE

    Fennell, Mark; Gallagher, Tommy; Vintro, Luis Leon; Osborne, Bruce

    2014-01-01

    Most research on the genetics of invasive plant species has focused on analyzing spatial differences among existing populations. Using a long-established Gunnera tinctoria population from Ireland, we evaluated the potential of using plants derived from seeds associated with different soil layers to track genetic variation through time. This species and site were chosen because (1) G. tinctoria produces a large and persistent seed bank; (2) it has been present in this locality, Sraheens, for ∼...

  16. Contrasting patterns of herbivore and predator pressure on invasive and native plants

    NARCIS (Netherlands)

    Engelkes, T.; Wouters, B.; Bezemer, T.M.; Harvey, J.A.; Van der Putten, W.H.

    2012-01-01

    Invasive non-nativeplant species often harbor fewer herbivorous insects than related nativeplant species. However, little is known about how herbivorous insects on non-nativeplants are exposed to carnivorous insects, and even less is known on plants that have recently expanded their ranges within

  17. Interactions between invasive plants and insect herbivores: A plea for a multitrophic perspective

    NARCIS (Netherlands)

    Harvey, J.A.; Bukovinszky, T.; Van der Putten, W.H.

    2010-01-01

    Invasive species represent one of the most important threats to biodiversity worldwide, with consequences for ecosystem functioning and the delivery of important ecological services to society. Several hypotheses have been generated to explain the success of exotic plants in their new ranges, with

  18. A strategic study of the impact of invasive alien plants in the high ...

    African Journals Online (AJOL)

    2006-07-20

    Jul 20, 2006 ... 2 National Working for Water Programme, Department of Water Affairs & Forestry, Private Bag X4390, Cape Town 8000, South Africa ... its public programme Working for Water (WfW) to develop a user charge system for the clearing of invasive alien plants in ... (WRM) charge, to cover the cost of clearing.

  19. A strategic study of the impact of invasive alien plants in the high ...

    African Journals Online (AJOL)

    The aim of this study was to develop a methodology to determine the impact of upland (non-riparian) invasive alien plants in the high rainfall catchments and riparian areas in all catchments on the total surface water yield available in each of the water management areas of South Africa. This would enable the Department of ...

  20. Effects of an invasive plant, Chinese tallow (Triadica sebifera), on development and survival of anuran larvae

    Science.gov (United States)

    Taylor B. Cotten; Matthew A. Kwiatkowski; Daniel Saenz; Michael Collyer

    2012-01-01

    Amphibians are considered one of the most threatened vertebrate groups. Although numerous studies have addressed the many causes of amphibian population decline, little is known about effects of invasive plants. Chinese tallow (Triadica sebifera) is an exotic deciduous tree that has invaded the southeastern United States. Amphibian larvae in environments invaded by T....

  1. Alien plant invasions in tropical and sub-tropical savannas: patterns, processes and prospects

    Czech Academy of Sciences Publication Activity Database

    Foxcroft, L. C.; Richardson, D. M.; Rejmánek, M.; Pyšek, Petr

    2010-01-01

    Roč. 12, č. 12 (2010), s. 3913-3933 ISSN 1387-3547 R&D Projects: GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60050516 Keywords : savannas * plant invasions * world Subject RIV: EF - Botanics Impact factor: 3.474, year: 2010

  2. Eco-friendly alternatives for control and use of invasive plants in agroforestry systems

    DEFF Research Database (Denmark)

    Nielsen, Mette Olaf; Pérez, M. Reinoso; Sørensen, Marten

    2013-01-01

    Artiklen er en del af transdiciplinært projekt om anvendelse af øko-venlige metoder til bekæmpelse af den invasive marabu-plante i Cuba. Ud over de naturvidenskabelige aspekter inddrager paperet human- og socialvindenskabelige dimensioner af problemstillingen....

  3. The more the better? The role of polyploidy in facilitating plant invasions

    Czech Academy of Sciences Publication Activity Database

    te Beest, M.; Le Roux, J. J.; Richardson, D. M.; Brysting, A. K.; Suda, Jan; Kubešová, Magdalena; Pyšek, Petr

    2012-01-01

    Roč. 109, č. 1 (2012), s. 19-45 ISSN 0305-7364 R&D Projects: GA ČR GA206/09/0563 Institutional research plan: CEZ:AV0Z60050516 Keywords : plant invasions * evolution * polyploidy Subject RIV: EF - Botanics Impact factor: 3.449, year: 2012

  4. Interactions between invasive plants and insect herbivores: a plea for a multitrophic perspective

    NARCIS (Netherlands)

    Harvey, J.A.; Bukovinszky, T.; Putten, van der W.H.

    2010-01-01

    Invasive species represent one of the most important threats to biodiversity worldwide, with consequences for ecosystem functioning and the delivery of important ecological services to society. Several hypotheses have been generated to explain the success of exotic plants in their new ranges, with

  5. The role of adaptive trans-generational plasticity in biological invasions of plants

    Science.gov (United States)

    Trans-generational plasticity (TGP) that confers greater offspring fitness is likely to be an important mechanism contributing to the spread of some invasive plant species. TGP is predicted for populations found in habitats with predictable spatial or temporal resource heterogeneity, and that have ...

  6. Plant invasions research in Latin America. Fast track to a more focused agenda

    Czech Academy of Sciences Publication Activity Database

    Gardener, M. R.; Bustamante, R.O.; Herrera, I.; Durigan, G.; Pivello, V.R.; Moro, M. F.; Stoll, A.; Langdon, B.; Baruch, Z.; Rico, Adriana; Arredondo-Nuńez, A.; Flores, S.

    2012-01-01

    Roč. 5, č. 2 (2012), s. 225-232 ISSN 1755-0874 Institutional research plan: CEZ:AV0Z60870520 Keywords : control * eradication * globalisation * inventories * novel ecosystem s * plant invasions * quarantine * Weed Risk Assessment Subject RIV: EH - Ecology, Behaviour Impact factor: 0.924, year: 2012

  7. Effects of biological control agents and exotic plant invasion on deer mouse populations

    Science.gov (United States)

    Yvette K. Ortega; Dean E. Pearson; Kevin S. McKelvey

    2004-01-01

    Exotic insects are commonly introduced as biological control agents to reduce densities of invasive exotic plants. Although current biocontrol programs for weeds take precautions to minimize ecological risks, little attention is paid to the potential nontarget effects of introduced food subsidies on native consumers. Previous research demonstrated that two gall flies (...

  8. Detection and monitoring of invasive exotic plants: a comparison of four sampling methods

    Science.gov (United States)

    Cynthia D. Huebner

    2007-01-01

    The ability to detect and monitor exotic invasive plants is likely to vary depending on the sampling method employed. Methods with strong qualitative thoroughness for species detection often lack the intensity necessary to monitor vegetation change. Four sampling methods (systematic plot, stratified-random plot, modified Whittaker, and timed meander) in hemlock and red...

  9. Distribution of Invasive Plants in Urban Environment Is Strongly Spatially Structured

    Czech Academy of Sciences Publication Activity Database

    Štajerová, Kateřina; Šmilauer, P.; Brůna, Josef; Pyšek, Petr

    2017-01-01

    Roč. 32, č. 3 (2017), s. 681-692 ISSN 0921-2973 R&D Projects: GA ČR GB14-36079G Institutional support: RVO:67985939 Keywords : invasive plant s * urban environment * species richness Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 3.615, year: 2016

  10. Danger to biodiversity of High Tatras by spreading of invasive plant species

    International Nuclear Information System (INIS)

    Strba, P.; Gogolakova, A.

    2010-01-01

    The aim of our work was to analyze the current status of invasive plant species - their generic representation and current extension (horizontal and vertical extension). The authors used the method of inventory of species richness. Sites were recorded on a tourist map and GPS (Garmin).

  11. Fire Alters Emergence of Invasive Plant Species from Soil Surface-Deposited Seeds

    Science.gov (United States)

    1. Fire is recognized as an important process controlling ecosystem structure and function. Restoration of fire regimes is complicated by global concerns about exotic plants invasions, yet little is known of how the two may interact. Characterizing relationships between fire conditions and the vi...

  12. Impact of invasions by alien plants on soil seed bank communities: emerging patterns

    Czech Academy of Sciences Publication Activity Database

    Gioria, Margherita; Jarošík, Vojtěch; Pyšek, Petr

    2014-01-01

    Roč. 16, č. 3 (2014), s. 132-142 ISSN 1433-8319 R&D Projects: GA ČR(CZ) GAP504/11/1028; GA ČR GB14-36079G Institutional support: RVO:67985939 Keywords : plant invasions * impact * soil seed bank Subject RIV: EF - Botanics Impact factor: 3.606, year: 2014

  13. Does the Data Resolution/origin Matter? Satellite, Airborne and Uav Imagery to Tackle Plant Invasions

    Science.gov (United States)

    Müllerová, Jana; Brůna, Josef; Dvořák, Petr; Bartaloš, Tomáš; Vítková, Michaela

    2016-06-01

    Invasive plant species represent a serious threat to biodiversity and landscape as well as human health and socio-economy. To successfully fight plant invasions, new methods enabling fast and efficient monitoring, such as remote sensing, are needed. In an ongoing project, optical remote sensing (RS) data of different origin (satellite, aerial and UAV), spectral (panchromatic, multispectral and color), spatial (very high to medium) and temporal resolution, and various technical approaches (object-, pixelbased and combined) are tested to choose the best strategies for monitoring of four invasive plant species (giant hogweed, black locust, tree of heaven and exotic knotweeds). In our study, we address trade-offs between spectral, spatial and temporal resolutions required for balance between the precision of detection and economic feasibility. For the best results, it is necessary to choose best combination of spatial and spectral resolution and phenological stage of the plant in focus. For species forming distinct inflorescences such as giant hogweed iterative semi-automated object-oriented approach was successfully applied even for low spectral resolution data (if pixel size was sufficient) whereas for lower spatial resolution satellite imagery or less distinct species with complicated architecture such as knotweed, combination of pixel and object based approaches was used. High accuracies achieved for very high resolution data indicate the possible application of described methodology for monitoring invasions and their long-term dynamics elsewhere, making management measures comparably precise, fast and efficient. This knowledge serves as a basis for prediction, monitoring and prioritization of management targets.

  14. Using life strategies to explore the vulnerability of ecosystem services to invasion by alien plants

    NARCIS (Netherlands)

    Vicente, J.; Pinro, A.; Araujo, M.; Lomba, A.; Randin, C.; Guisan, A.; Honrado, J.; Verburg, P.H.

    2013-01-01

    Invasive plants can have different effects on ecosystem functioning and on the provision of ecosystem services, with the direction and magnitude of such effects depending on the service and ecosystem being considered, but also on the life strategies of the invaders. Strategies can influence

  15. Preliminary assessment of the impacts of invasive alien plants on ecosystem services in South Africa

    CSIR Research Space (South Africa)

    Van Wilgen, BW

    2006-01-01

    Full Text Available and invasive alien plant infestations, and to use the two to estimate impacts on each of the services. In this paper our focus is on water resources only. We describe our approach for selecting species and areas in order to estimate current and future potential...

  16. Potential for biotic resistance from herbivores to tropical and subtropical plant invasions in aquatic ecosystems

    NARCIS (Netherlands)

    Petruzella, A.; Grutters, B.M.C.; Thomaz, S.M.; Bakker, E.S.

    2017-01-01

    Invasions of tropical and subtropical aquatic plants threaten biodiversity and cause ecological and economic impacts worldwide. An urgent question is whether native herbivores are able to inhibit the spread of these alien species thus providing biotic resistance. The potential for biotic resistance

  17. EMAPi 2015: Highlighting links between science and management of alien plant invasions

    Czech Academy of Sciences Publication Activity Database

    Daehler, C. C.; van Kleunen, M.; Pyšek, Petr; Richardson, D. M.

    2016-01-01

    Roč. 30, č. 1 (2016), s. 1-3 ISSN 1619-0033 Grant - others:AV ČR(CZ) AP1002 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985939 Keywords : invasions * plants * animals Subject RIV: EH - Ecology, Behaviour

  18. Projecting trends in plant invasions in Europe under different scenarios of future land-use change

    Czech Academy of Sciences Publication Activity Database

    Chytrý, M.; Wild, Jan; Pyšek, Petr; Jarošík, Vojtěch; Dendoncker, N.; Reginster, I.; Pino, J.; Maskell, L. C.; Vila, M.; Pergl, Jan; Kühn, I.; Spangenberg, J.H.; Settele, J.

    2012-01-01

    Roč. 21, č. 1 (2012), s. 75-87 ISSN 1466-822X R&D Projects: GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60050516 Institutional support: RVO:67985939 Keywords : plant invasions * land-use change * prediction Subject RIV: EF - Botanics Impact factor: 7.223, year: 2012

  19. Invasive plant species alters consumer behavior by providing refuge from predation.

    Science.gov (United States)

    Dutra, Humberto P; Barnett, Kirk; Reinhardt, Jason R; Marquis, Robert J; Orrock, John L

    2011-07-01

    Understanding the effects of invasive plants on native consumers is important because consumer-mediated indirect effects have the potential to alter the dynamics of coexistence in native communities. Invasive plants may promote changes in consumer pressure due to changes in protective cover (i.e., the architectural complexity of the invaded habitat) and in food availability (i.e., subsidies of fruits and seeds). No experimental studies have evaluated the relative interplay of these two effects. In a factorial experiment, we manipulated cover and food provided by the invasive shrub Amur honeysuckle (Lonicera maackii) to evaluate whether this plant alters the foraging activity of native mammals. Using tracking plates to quantify mammalian foraging activity, we found that removal of honeysuckle cover, rather than changes in the fruit resources it provides, reduced the activity of important seed consumers, mice in the genus Peromyscus. Two mesopredators, Procyon lotor and Didelphis virginiana, were also affected. Moreover, we found rodents used L. maackii for cover only on cloudless nights, indicating that the effect of honeysuckle was weather-dependent. Our work provides experimental evidence that this invasive plant species changes habitat characteristics, and in so doing alters the behavior of small- and medium-sized mammals. Changes in seed predator behavior may lead to cascading effects on the seeds that mice consume.

  20. Clearing of invasive alien plants in South Africa: a preliminary assessment of costs and progress

    CSIR Research Space (South Africa)

    Marais, R

    2004-01-01

    Full Text Available This paper provides estimates of the costs of clearing important species of invasive alien plants, as well as of progress made with clearing, based on data from a recently developed GIS-based project information system. Before the deployment...

  1. Invasive plants as potential food resource for native pollinators: A case study with two invasive species and a generalist bumble bee.

    Science.gov (United States)

    Drossart, Maxime; Michez, Denis; Vanderplanck, Maryse

    2017-11-24

    It is now well established that invasive plants may induce drifts in the quantity and/or quality of floral resources. They are then often pointed out as a potential driver of bee decline. However, their impact on bee population remains quite unclear and still controversial, as bee responses are highly variable among species. Here, we compared the amino acid composition of pollen from three native and two invasive plant species included in diets of common pollinators in NW Europe. Moreover, the nutritional intake (i.e., pollen and amino acid intakes) of Bombus terrestris colonies and the pollen foraging behaviour of workers (i.e., visiting rate, number of foraging trips, weight of pollen loads) were considered. We found significant differences in pollen nutrients among the studied species according to the plant invasive behaviour. We also found significant differences in pollen foraging behaviour according to the plant species, from few to several foraging trips carrying small or large pollen loads. Such behavioural differences directly impacted the pollen intake but depended more likely on plant morphology rather than on plant invasive behaviour. These results suggest that common generalist bumble bees might not always suffer from plant invasions, depending on their behavioural plasticity and nutritional requirements.

  2. Herbivory of an invasive slug is affected by earthworms and the composition of plant communities.

    Science.gov (United States)

    Zaller, Johann G; Parth, Myriam; Szunyogh, Ilona; Semmelrock, Ines; Sochurek, Susanne; Pinheiro, Marcia; Frank, Thomas; Drapela, Thomas

    2013-05-13

    Biodiversity loss and species invasions are among the most important human-induced global changes. Moreover, these two processes are interlinked as ecosystem invasibility is considered to increase with decreasing biodiversity. In temperate grasslands, earthworms serve as important ecosystem engineers making up the majority of soil faunal biomass. Herbivore behaviour has been shown to be affected by earthworms, however it is unclear whether these effects differ with the composition of plant communities. To test this we conducted a mesocosm experiment where we added earthworms (Annelida: Lumbricidae) to planted grassland communities with different plant species composition (3 vs. 12 plant spp.). Plant communities had equal plant densities and ratios of the functional groups grasses, non-leguminous forbs and legumes. Later, Arion vulgaris slugs (formerly known as A. lusitanicus; Gastropoda: Arionidae) were added and allowed to freely choose among the available plant species. This slug species is listed among the 100 worst alien species in Europe. We hypothesized that (i) the food choice of slugs would be altered by earthworms' specific effects on the growth and nutrient content of plant species, (ii) slug herbivory will be less affected by earthworms in plant communities containing more plant species than in those with fewer plant species because of a more readily utilization of plant resources making the impacts of earthworms less pronounced. Slug herbivory was significantly affected by both earthworms and plant species composition. Slugs damaged 60% less leaves when earthworms were present, regardless of the species composition of the plant communities. Percent leaf area consumed by slugs was 40% lower in communities containing 12 plant species; in communities containing only three species earthworms increased slug leaf area consumption. Grasses were generally avoided by slugs. Leaf length and number of tillers was increased in mesocosms containing more plant

  3. Testing Carea varipes and Neostauropus alternus as biological control agents for the Florida invasive plant species Rhodomyrtus tomentosa.

    Science.gov (United States)

    Rhodomyrtus tomentosa (RT) a native plant to Southeastern Asia, commonly known as downy rose myrtle, is invasive to the regions of Central and South Florida. Introduced in the early 1920’s, this weed is currently considered a Category I invasive species by the Florida Exotic Pest Plant Council. RT...

  4. Predicting trends of invasive plants richness using local socio-economic data: An application in North Portugal

    International Nuclear Information System (INIS)

    Santos, Mario; Freitas, Raul; Crespi, Antonio L.; Hughes, Samantha Jane; Cabral, Joao Alexandre

    2011-01-01

    This study assesses the potential of an integrated methodology for predicting local trends in invasive exotic plant species (invasive richness) using indirect, regional information on human disturbance. The distribution of invasive plants was assessed in North Portugal using herbarium collections and local environmental, geophysical and socio-economic characteristics. Invasive richness response to anthropogenic disturbance was predicted using a dynamic model based on a sequential modeling process (stochastic dynamic methodology-StDM). Derived scenarios showed that invasive richness trends were clearly associated with ongoing socio-economic change. Simulations including scenarios of growing urbanization showed an increase in invasive richness while simulations in municipalities with decreasing populations showed stable or decreasing levels of invasive richness. The model simulations demonstrate the interest and feasibility of using this methodology in disturbance ecology. - Highlights: → Socio-economic data indicate human induced disturbances. → Socio-economic development increase disturbance in ecosystems. → Disturbance promotes opportunities for invasive plants.→ Increased opportunities promote richness of invasive plants.→ Increase in richness of invasive plants change natural ecosystems.

  5. Predicting trends of invasive plants richness using local socio-economic data: An application in North Portugal

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Mario, E-mail: mgsantoss@gmail.com [Laboratory of Applied Ecology, CITAB-Centre for the Research and Technology of Agro-Environment and Biological Sciences, University of Tras-os-Montes e Alto Douro, 5000-911 Vila Real (Portugal); Freitas, Raul, E-mail: raulfreitas@portugalmail.com [Herbarium, UTAD Botanical Garden, CITAB-Centre for the Research and Technology of Agro-Environment and Biological Sciences, University of Tras-os-Montes e Alto Douro, 5000-911 Vila Real (Portugal); Crespi, Antonio L., E-mail: aluis.crespi@gmail.com [Herbarium, UTAD Botanical Garden, CITAB-Centre for the Research and Technology of Agro-Environment and Biological Sciences, University of Tras-os-Montes e Alto Douro, 5000-911 Vila Real (Portugal); Hughes, Samantha Jane, E-mail: shughes@utad.pt [Department of Forest and Landscape, CITAB-Centre for the Research and Technology of Agro-Environment and Biological Sciences, University of Tras-os-Montes e Alto Douro, 5000-911 Vila Real (Portugal); Cabral, Joao Alexandre, E-mail: jcabral@utad.pt [Laboratory of Applied Ecology, CITAB-Centre for the Research and Technology of Agro-Environment and Biological Sciences, University of Tras-os-Montes e Alto Douro, 5000-911 Vila Real (Portugal)

    2011-10-15

    This study assesses the potential of an integrated methodology for predicting local trends in invasive exotic plant species (invasive richness) using indirect, regional information on human disturbance. The distribution of invasive plants was assessed in North Portugal using herbarium collections and local environmental, geophysical and socio-economic characteristics. Invasive richness response to anthropogenic disturbance was predicted using a dynamic model based on a sequential modeling process (stochastic dynamic methodology-StDM). Derived scenarios showed that invasive richness trends were clearly associated with ongoing socio-economic change. Simulations including scenarios of growing urbanization showed an increase in invasive richness while simulations in municipalities with decreasing populations showed stable or decreasing levels of invasive richness. The model simulations demonstrate the interest and feasibility of using this methodology in disturbance ecology. - Highlights: {yields} Socio-economic data indicate human induced disturbances. {yields} Socio-economic development increase disturbance in ecosystems. {yields} Disturbance promotes opportunities for invasive plants.{yields} Increased opportunities promote richness of invasive plants.{yields} Increase in richness of invasive plants change natural ecosystems.

  6. Exploring public perception of non-native species from a visions of nature perspective.

    Science.gov (United States)

    Verbrugge, Laura N H; Van den Born, Riyan J G; Lenders, H J Rob

    2013-12-01

    Not much is known about lay public perceptions of non-native species and their underlying values. Public awareness and engagement, however, are important aspects in invasive species management. In this study, we examined the relations between the lay public's visions of nature, their knowledge about non-native species, and their perceptions of non-native species and invasive species management with a survey administered in the Netherlands. Within this framework, we identified three measures for perception of non-native species: perceived risk, control and engagement. In general, respondents scored moderate values for perceived risk and personal engagement. However, in case of potential ecological or human health risks, control measures were supported. Respondents' images of the human-nature relationship proved to be relevant in engagement in problems caused by invasive species and in recognizing the need for control, while images of nature appeared to be most important in perceiving risks to the environment. We also found that eradication of non-native species was predominantly opposed for species with a high cuddliness factor such as mammals and bird species. We conclude that lay public perceptions of non-native species have to be put in a wider context of visions of nature, and we discuss the implications for public support for invasive species management.

  7. The Impact of the Invasive Alien Plant, Impatiens glandulifera, on Pollen Transfer Networks.

    Directory of Open Access Journals (Sweden)

    Carine Emer

    Full Text Available Biological invasions are a threat to the maintenance of ecological processes, including pollination. Plant-flower visitor networks are traditionally used as a surrogated for pollination at the community level, despite they do not represent the pollination process, which takes place at the stigma of plants where pollen grains are deposited. Here we investigated whether the invasion of the alien plant Impatiens glandulifera (Balsaminaceae affects pollen transfer at the community level. We asked whether more alien pollen is deposited on the stigmas of plants on invaded sites, whether deposition is affected by stigma type (dry, semidry and wet and whether the invasion of I. glandulifera changes the structure of the resulting pollen transfer networks. We sampled stigmas of plants on 10 sites invaded by I. glandulifera (hereafter, balsam and 10 non-invaded control sites. All 20 networks had interactions with balsam pollen, although significantly more balsam pollen was found on plants with dry stigmas in invaded areas. Balsam pollen deposition was restricted to a small subset of plant species, which is surprising because pollinators are known to carry high loads of balsam pollen. Balsam invasion did not affect the loading of native pollen, nor did it affect pollen transfer network properties; networks were modular and poorly nested, both of which are likely to be related to the specificity of pollen transfer interactions. Our results indicate that pollination networks become more specialized when moving from the flower visitation to the level of pollen transfer networks. Therefore, caution is needed when inferring pollination from patterns of insect visitation or insect pollen loads as the relationship between these and pollen deposition is not straightforward.

  8. Competitive interactions between native and invasive exotic plant species are altered under elevated carbon dioxide.

    Science.gov (United States)

    Manea, Anthony; Leishman, Michelle R

    2011-03-01

    We hypothesized that the greater competitive ability of invasive exotic plants relative to native plants would increase under elevated CO(2) because they typically have traits that confer the ability for fast growth when resources are not limiting and thus are likely to be more responsive to elevated CO(2). A series of competition experiments under ambient and elevated CO(2) glasshouse conditions were conducted to determine an index of relative competition intensity for 14 native-invasive exotic species-pairs. Traits including specific leaf area, leaf mass ratio, leaf area ratio, relative growth rate, net assimilation rate and root weight ratio were measured. Competitive rankings within species-pairs were not affected by CO(2) concentration: invasive exotic species were more competitive in 9 of the 14 species-pairs and native species were more competitive in the remaining 5 species-pairs, regardless of CO(2) concentration. However, there was a significant interaction between plant type and CO(2) treatment due to reduced competitive response of native species under elevated compared with ambient CO(2) conditions. Native species had significantly lower specific leaf area and leaf area ratio under elevated compared with ambient CO(2). We also compared traits of more-competitive with less-competitive species, regardless of plant type, under both CO(2) treatments. More-competitive species had smaller leaf weight ratio and leaf area ratio, and larger relative growth rate and net assimilation rate under both ambient and elevated CO(2) conditions. These results suggest that growth and allocation traits can be useful predictors of the outcome of competitive interactions under both ambient and elevated CO(2) conditions. Under predicted future atmospheric CO(2) conditions, competitive rankings among species may not change substantially, but the relative success of invasive exotic species may be increased. Thus, under future atmospheric CO(2) conditions, the ecological and

  9. The role of adaptive trans-generational plasticity in biological invasions of plants.

    Science.gov (United States)

    Dyer, Andrew R; Brown, Cynthia S; Espeland, Erin K; McKay, John K; Meimberg, Harald; Rice, Kevin J

    2010-03-01

    High-impact biological invasions often involve establishment and spread in disturbed, high-resource patches followed by establishment and spread in biotically or abiotically stressful areas. Evolutionary change may be required for the second phase of invasion (establishment and spread in stressful areas) to occur. When species have low genetic diversity and short selection history, within-generation phenotypic plasticity is often cited as the mechanism through which spread across multiple habitat types can occur. We show that trans-generational plasticity (TGP) can result in pre-adapted progeny that exhibit traits associated with increased fitness both in high-resource patches and in stressful conditions. In the invasive sedge, Cyperus esculentus, maternal plants growing in nutrient-poor patches can place disproportional number of propagules into nutrient-rich patches. Using the invasive annual grass, Aegilops triuncialis, we show that maternal response to soil conditions can confer greater stress tolerance in seedlings in the form of greater photosynthetic efficiency. We also show TGP for a phenological shift in a low resource environment that results in greater stress tolerance in progeny. These lines of evidence suggest that the maternal environment can have profound effects on offspring success and that TGP may play a significant role in some plant invasions.

  10. Global Invader Impact Network (GIIN): toward standardized evaluation of the ecological impacts of invasive plants.

    Science.gov (United States)

    Barney, Jacob N; Tekiela, Daniel R; Barrios-Garcia, Maria Noelia; Dimarco, Romina D; Hufbauer, Ruth A; Leipzig-Scott, Peter; Nuñez, Martin A; Pauchard, Aníbal; Pyšek, Petr; Vítková, Michaela; Maxwell, Bruce D

    2015-07-01

    Terrestrial invasive plants are a global problem and are becoming ubiquitous components of most ecosystems. They are implicated in altering disturbance regimes, reducing biodiversity, and changing ecosystem function, sometimes in profound and irreversible ways. However, the ecological impacts of most invasive plants have not been studied experimentally, and most research to date focuses on few types of impacts, which can vary greatly among studies. Thus, our knowledge of existing ecological impacts ascribed to invasive plants is surprisingly limited in both breadth and depth. Our aim was to propose a standard methodology for quantifying baseline ecological impact that, in theory, is scalable to any terrestrial plant invader (e.g., annual grasses to trees) and any invaded system (e.g., grassland to forest). The Global Invader Impact Network (GIIN) is a coordinated distributed experiment composed of an observational and manipulative methodology. The protocol consists of a series of plots located in (1) an invaded area; (2) an adjacent removal treatment within the invaded area; and (3) a spatially separate uninvaded area thought to be similar to pre-invasion conditions of the invaded area. A standardized and inexpensive suite of community, soil, and ecosystem metrics are collected allowing broad comparisons among measurements, populations, and species. The method allows for one-time comparisons and for long-term monitoring enabling one to derive information about change due to invasion over time. Invader removal plots will also allow for quantification of legacy effects and their return rates, which will be monitored for several years. GIIN uses a nested hierarchical scale approach encompassing multiple sites, regions, and continents. Currently, GIIN has network members in six countries, with new members encouraged. To date, study species include representatives of annual and perennial grasses; annual and perennial forbs; shrubs; and trees. The goal of the GIIN

  11. Few effects of invasive plants Reynoutria japonica, Rudbeckia laciniata and Solidago gigantea on soil physical and chemical properties.

    Science.gov (United States)

    Stefanowicz, Anna M; Stanek, Małgorzata; Nobis, Marcin; Zubek, Szymon

    2017-01-01

    Biological invasions are an important problem of human-induced changes at a global scale. Invasive plants can modify soil nutrient pools and element cycling, creating feedbacks that potentially stabilize current or accelerate further invasion, and prevent re-establishment of native species. The aim of this study was to compare the effects of Reynoutria japonica, Rudbeckia laciniata and Solidago gigantea, invading non-forest areas located within or outside river valleys, on soil physical and chemical parameters, including soil moisture, element concentrations, organic matter content and pH. Additionally, invasion effects on plant species number and total plant cover were assessed. The concentrations of elements in shoots and roots of invasive and native plants were also measured. Split-plot ANOVA revealed that the invasions significantly reduced plant species number, but did not affect most soil physical and chemical properties. The invasions decreased total P concentration and increased N-NO 3 concentration in soil in comparison to native vegetation, though the latter only in the case of R. japonica. The influence of invasion on soil properties did not depend on location (within- or outside valleys). The lack of invasion effects on most soil properties does not necessarily imply the lack of influence of invasive plants, but may suggest that the direction of the changes varies among replicate sites and there are no general patterns of invasion-induced alterations for these parameters. Tissue element concentrations, with the exception of Mg, did not differ between invasive and native plants, and were not related to soil element concentrations. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Invasion strategies in clonal aquatic plants: Are phenotypic differences caused by phenotypic plasticity or local adaptation?

    DEFF Research Database (Denmark)

    Riis, Tenna; Lambertini, Carla; Olesen, Birgit

    2010-01-01

    conditions and plant morphological characteristics. Conclusions: The results indicate that at the current stage of spread into New Zealand, the primary adaptive strategy of these three invasive macrophytes is phenotypic plasticity. However, while limited, the possibility that genetic diversity between......Background and Aims: The successful spread of invasive plants in new environments is often linked to multiple introductions and a diverse gene pool that facilitates local adaptation to variable environmental conditions. For clonal plants, however, phenotypic plasticity may be equally important....... Methods: Field populations with a large phenotypic variety were sampled in a range of lakes and streams with different chemical and physical properties. The phenotypic plasticity of the species before and after cultivation was studied in a common garden growth experiment, and the genetic diversity...

  13. INVASIVE PLANTS IN MOUNTAINOUS REMNANT FOREST: RECOMMENDATION FOR CHOOSING BEST DECISION FOR INVASIVE SPECIES MANAGEMENT OF Cestrum aurantiacum Lindl.

    Directory of Open Access Journals (Sweden)

    Decky Indrawan Junaedi

    2012-01-01

    Full Text Available Cestrum aurantiacum Lindl. is an exotic species found in native remnant forest of GPNP which is located inside the Cibodas Botanic Garden (CBG. Risk assessment is an important tool to choose best decision for invasive plant management.  Risk assessment analysis on C. aurantiacum in Cibodas Botanic Garden was conducted using Multi Criteria Decision Analysis (MCDA method.  Analytical Hierarchy Process (AHP used in the valuation process. Three sub-criteria used: minimizing the ecological impact, minimizing the management cost, and maximizing the public acceptance. Five management alternatives were used: do nothing (DN, eradication (E, containment (C, bio-control (BC and harvesting (H. Harvesting (H recommended as the best management decision for C. aurantiacumin at CBG remnant forest. This harvesting decision is not only creating environment/ ecosystem remediation but also as sources of fund in the management activity of the area.

  14. DNA barcoding discriminates the noxious invasive plant species, floating pennywort (Hydrocotyle ranunculoides L.f.), from non-invasive relatives.

    Science.gov (United States)

    VAN DE Wiel, C C M; VAN DER Schoot, J; VAN Valkenburg, J L C H; Duistermaat, H; Smulders, M J M

    2009-07-01

    Floating pennywort (Hydrocotyle ranunculoides L.f.), a member of the plant family Araliaceae originating from North America, is an example of an invasive aquatic species posing serious problems to the management of waterways outside of its original distribution area in Australia and Western Europe. As a consequence, its import was banned in the Netherlands. It can be difficult to distinguish H. ranunculoides from other species of the genus on a morphological basis. In this regard, DNA barcoding may become a good alternative once this could be performed on a routine basis. In this study, we show that it is possible to distinguish H. ranunculoides from a series of closely related congeners by using a single plastid DNA sequence, trnH-psbA. © 2009 Blackwell Publishing Ltd.

  15. Isolation and characterization of polymorphic microsatellite loci from the invasive plant Solidago canadensis (Asteraceae).

    Science.gov (United States)

    Zhao, S-Y; Sun, S-G; Guo, Y-H; Chen, J-M; Wang, Q-F

    2012-02-17

    Solidago canadensis, a clonal herb originally from North America (common name: Canada goldenrod), is an invasive species in many countries. We developed microsatellite primers for this species. Eleven polymorphic loci were generated and primers were designed. Polymorphism of these 11 loci was assessed in 35 plants from two populations (Wuhan and Shanghai) in China. The number of alleles per locus ranged from 3 to 14. The observed and expected heterozygosities varied from 0.0732 to 0.7391 and from 0.1177 to 0.8687, respectively. These microsatellite markers will be useful tools for studies of population genetics in the native and invasive range of this species.

  16. Grasses as invasive plants in South Africa revisited: Patterns, pathways and management

    Directory of Open Access Journals (Sweden)

    Vernon Visser

    2017-03-01

    Full Text Available Background: In many countries around the world, the most damaging invasive plant species are grasses. However, the status of grass invasions in South Africa has not been documented recently. Objectives: To update Sue Milton’s 2004 review of grasses as invasive alien plants in South Africa, provide the first detailed species level inventory of alien grasses in South Africa and assess the invasion dynamics and management of the group. Method: We compiled the most comprehensive inventory of alien grasses in South Africa to date using recorded occurrences of alien grasses in the country from various literature and database sources. Using historical literature, we reviewed past efforts to introduce alien grasses into South Africa. We sourced information on the origins, uses, distributions and minimum residence times to investigate pathways and patterns of spatial extent. We identified alien grasses in South Africa that are having environmental and economic impacts and determined whether management options have been identified, and legislation created, for these species. Results: There are at least 256 alien grass species in the country, 37 of which have become invasive. Alien grass species richness increased most dramatically from the late 1800s to about 1940. Alien grass species that are not naturalised or invasive have much shorter residence times than those that have naturalised or become invasive. Most grasses were probably introduced for forage purposes, and a large number of alien grass species were trialled at pasture research stations. A large number of alien grass species in South Africa are of Eurasian origin, although more recent introductions include species from elsewhere in Africa and from Australasia. Alien grasses are most prevalent in the south-west of the country, and the Fynbos Biome has the most alien grasses and the most widespread species. We identified 11 species that have recorded environmental and economic impacts in the

  17. Distribution of invasive and native riparian woody plants across the western USA in relation to climate, river flow, floodplain geometry and patterns of introduction

    Science.gov (United States)

    Ryan McShane,; Daniel Auerbach,; Friedman, Jonathan M.; Auble, Gregor T.; Shafroth, Patrick B.; Michael Merigliano,; Scott, Michael L.; N. Leroy Poff,

    2015-01-01

    Management of riparian plant invasions across the landscape requires understanding the combined influence of climate, hydrology, geologic constraints and patterns of introduction. We measured abundance of nine riparian woody taxa at 456 stream gages across the western USA. We constructed conditional inference recursive binary partitioning models to discriminate the influence of eleven environmental variables on plant occurrence and abundance, focusing on the two most abundant non-native taxa, Tamarix spp. and Elaeagnus angustifolia, and their native competitor Populus deltoides. River reaches in this study were distributed along a composite gradient from cooler, wetter higher-elevation reaches with higher stream power and earlier snowmelt flood peaks to warmer, drier lower-elevation reaches with lower power and later peaks. Plant distributions were strongly related to climate, hydrologic and geomorphic factors, and introduction history. The strongest associations were with temperature and then precipitation. Among hydrologic and geomorphic variables, stream power, peak flow timing and 10-yr flood magnitude had stronger associations than did peak flow predictability, low-flow magnitude, mean annual flow and channel confinement. Nearby intentional planting of Elaeagnus was the best predictor of its occurrence, but planting of Tamarix was rare. Higher temperatures were associated with greater abundance of Tamarix relative to P. deltoides, and greater abundance of P. deltoides relative toElaeagnus. Populus deltoides abundance was more strongly related to peak flow timing than was that of Elaeagnus or Tamarix. Higher stream power and larger 10-yr floods were associated with greater abundance of P. deltoides and Tamarix relative to Elaeagnus. Therefore, increases in temperature could increase abundance of Tamarix and decrease that of Elaeagnus relative to P. deltoides, changes in peak flow timing caused by climate change or dam operations could

  18. Is invasion success of Australian trees mediated by their native biogeography, phylogenetic history, or both?

    Science.gov (United States)

    Miller, Joseph T; Hui, Cang; Thornhill, Andrew; Gallien, Laure; Le Roux, Johannes J; Richardson, David M

    2016-12-30

    For a plant species to become invasive it has to progress along the introduction-naturalization-invasion (INI) continuum which reflects the joint direction of niche breadth. Identification of traits that correlate with and drive species invasiveness along the continuum is a major focus of invasion biology. If invasiveness is underlain by heritable traits, and if such traits are phylogenetically conserved, then we would expect non-native species with different introduction status (i.e. position along the INI continuum) to show phylogenetic signal. This study uses two clades that contain a large number of invasive tree species from the genera Acacia and Eucalyptus to test whether geographic distribution and a novel phylogenetic conservation method can predict which species have been introduced, became naturalized, and invasive. Our results suggest that no underlying phylogenetic signal underlie the introduction status for both groups of trees, except for introduced acacias. The more invasive acacia clade contains invasive species that have smoother geographic distributions and are more marginal in the phylogenetic network. The less invasive eucalyptus group contains invasive species that are more clustered geographically, more centrally located in the phylogenetic network and have phylogenetic distances between invasive and non-invasive species that are trending toward the mean pairwise distance. This suggests that highly invasive groups may be identified because they have invasive species with smoother and faster expanding native distributions and are located more to the edges of phylogenetic networks than less invasive groups. Published by Oxford University Press on behalf of the Annals of Botany Company.

  19. Alkaloid concentration of the invasive plant species Ulex europaeus in relation to geographic origin and herbivory

    Science.gov (United States)

    Hornoy, Benjamin; Atlan, Anne; Tarayre, Michèle; Dugravot, Sébastien; Wink, Michael

    2012-11-01

    In the study of plant defense evolution, invasive plant species can be very insightful because they are often introduced without their enemies, and traits linked to defense can be released from selective pressures and evolve. Further, studying plant defense evolution in invasive species is important for biological control and use of these species. In this study, we investigated the evolution of the defensive chemicals quinolizidine alkaloids (QAs) in the invasive species gorse, Ulex europaeus. Using a common garden experiment, our goals were to characterize the role of QAs relative to specialist enemies of gorse and to investigate if QA concentration evolved in invaded regions, where gorse was introduced without these enemies. Our results showed that pod infestation rate by the seed predator Exapion ulicis and infestation by the rust pathogen Uromyces genistae-tinctoriae were negatively correlated to concentration of the QA lupanine. Quinolizidine alkaloid concentration was very variable between individuals, both within and among populations, but it was not different between native and invaded regions, suggesting that no evolution of decreased resistance occurred after gorse lost its enemies. Our study also suggests that QA concentrations are traits integrated into seed predation avoidance strategies of gorse, with plants that mass-fruit in spring but do not escape pod infestation in time being richer in QAs.

  20. Livestock as a potential biological control agent for an invasive wetland plant

    Directory of Open Access Journals (Sweden)

    Brian R. Silliman

    2014-09-01

    Full Text Available Invasive species threaten biodiversity and incur costs exceeding billions of US$. Eradication efforts, however, are nearly always unsuccessful. Throughout much of North America, land managers have used expensive, and ultimately ineffective, techniques to combat invasive Phragmites australis in marshes. Here, we reveal that Phragmites may potentially be controlled by employing an affordable measure from its native European range: livestock grazing. Experimental field tests demonstrate that rotational goat grazing (where goats have no choice but to graze Phragmites can reduce Phragmites cover from 100 to 20% and that cows and horses also readily consume this plant. These results, combined with the fact that Europeans have suppressed Phragmites through seasonal livestock grazing for 6,000 years, suggest Phragmites management can shift to include more economical and effective top-down control strategies. More generally, these findings support an emerging paradigm shift in conservation from high-cost eradication to economically sustainable control of dominant invasive species.

  1. Seed dispersal networks in the Galápagos and the consequences of alien plant invasions

    DEFF Research Database (Denmark)

    Heleno, R. H.; Olesen, Jens Mogens; Nogales, M.

    2013-01-01

    Alien plants are a growing threat to the Gala´pagos unique biota. We evaluated the impact of alien plants on eight seed dispersal networks from two islands of the archipelago. Nearly 10 000 intact seeds from 58 species were recovered from the droppings of 18 bird and reptile dispersers. The most......, followed by small ground finch, two mockingbirds, the giant tortoise and two insectivorous birds. Most animals dispersed alien seeds, but these formed a relatively small proportion of the interactions. Nevertheless, the integration of aliens was higher in the island that has been invaded for longest......, suggesting a time-lag between alien plant introductions and their impacts on seed dispersal networks. Alien plants become more specialized with advancing invasion, favouring more simplified plant and disperser communities. However, only habitat type significantly affected the overall network structure. Alien...

  2. Pythium invasion of plant-based life support systems: biological control and sources

    Science.gov (United States)

    Jenkins, D. G.; Cook, K. L.; Garland, J. L.; Board, K. F.; Sager, J. C. (Principal Investigator)

    2000-01-01

    Invasion of plant-based life support systems by plant pathogens could cause plant disease and disruption of life support capability. Root rot caused by the fungus, Pythium, was observed during tests of prototype plant growth systems containing wheat at the Kennedy Space Center (KSC). We conducted experiments to determine if the presence of complex microbial communities in the plant root zone (rhizosphere) resisted invasion by the Pythium species isolated from the wheat root. Rhizosphere inocula of different complexity (as assayed by community-level physiological profile: CLPP) were developed using a dilution/extinction approach, followed by growth in hydroponic rhizosphere. Pythium growth on wheat roots and concomitant decreases in plant growth were inversely related to the complexity of the inocula during 20-day experiments in static hydroponic systems. Pythium was found on the seeds of several different wheat cultivars used in controlled environmental studies, but it is unclear if the seed-borne fungal strain(s) were identical to the pathogenic strain recovered from the KSC studies. Attempts to control pathogens and their effects in hydroponic life support systems should include early inoculation with complex microbial communities, which is consistent with ecological theory.

  3. Pollination and reproduction of an invasive plant inside and outside its ancestral range

    Science.gov (United States)

    Petanidou, Theodora; Price, Mary V.; Bronstein, Judith L.; Kantsa, Aphrodite; Tscheulin, Thomas; Kariyat, Rupesh; Krigas, Nikos; Mescher, Mark C.; De Moraes, Consuelo M.; Waser, Nickolas M.

    2018-05-01

    Comparing traits of invasive species within and beyond their ancestral range may improve our understanding of processes that promote aggressive spread. Solanum elaeagnifolium (silverleaf nightshade) is a noxious weed in its ancestral range in North America and is invasive on other continents. We compared investment in flowers and ovules, pollination success, and fruit and seed set in populations from Arizona, USA ("AZ") and Greece ("GR"). In both countries, the populations we sampled varied in size and types of present-day disturbance. Stature of plants increased with population size in AZ samples whereas GR plants were uniformly tall. Taller plants produced more flowers, and GR plants produced more flowers for a given stature and allocated more ovules per flower. Similar functional groups of native bees pollinated in AZ and GR populations, but visits to flowers decreased with population size and we observed no visits in the largest GR populations. As a result, plants in large GR populations were pollen-limited, and estimates of fecundity were lower on average in GR populations despite the larger allocation to flowers and ovules. These differences between plants in our AZ and GR populations suggest promising directions for further study. It would be useful to sample S. elaeagnifolium in Mediterranean climates within the ancestral range (e.g., in California, USA), to study asexual spread via rhizomes, and to use common gardens and genetic studies to explore the basis of variation in allocation patterns and of relationships between visitation and fruit set.

  4. Invasive Species Science Branch: research and management tools for controlling invasive species

    Science.gov (United States)

    Reed, Robert N.; Walters, Katie D.

    2015-01-01

    Invasive, nonnative species of plants, animals, and disease organisms adversely affect the ecosystems they enter. Like “biological wildfires,” they can quickly spread and affect nearly all terrestrial and aquatic ecosystems. Invasive species have become one of the greatest environmental challenges of the 21st century in economic, environmental, and human health costs, with an estimated effect in the United States of more than $120 billion per year. Managers of the Department of the Interior and other public and private lands often rank invasive species as their top resource management problem. The Invasive Species Science Branch of the Fort Collins Science Center provides research and technical assistance relating to management concerns for invasive species, including understanding how these species are introduced, identifying areas vulnerable to invasion, forecasting invasions, and developing control methods. To disseminate this information, branch scientists are developing platforms to share invasive species information with DOI cooperators, other agency partners, and the public. From these and other data, branch scientists are constructing models to understand and predict invasive species distributions for more effective management. The branch also has extensive herpetological and population biology expertise that is applied to harmful reptile invaders such as the Brown Treesnake on Guam and Burmese Python in Florida.

  5. Maps of the level of invasion of the Czech Republic by alien plants

    Czech Academy of Sciences Publication Activity Database

    Chytrý, M.; Wild, Jan; Pyšek, Petr; Tichý, L.; Danihelka, Jiří; Knollová, I.

    2009-01-01

    Roč. 81, č. 3 (2009), s. 187-207 ISSN 0032-7786 R&D Projects: GA MŠk LC06073 Grant - others:Evropská komise(XE) GOCE-CT-2003-506675 Institutional research plan: CEZ:AV0Z60050516 Keywords : plant invasions * distribution * mapping Subject RIV: EF - Botanics Impact factor: 2.638, year: 2009 http://www.preslia.cz/P093Chytry.pdf

  6. Global trade will accelerate plant invasions in emerging economies under climate change

    Czech Academy of Sciences Publication Activity Database

    Seebens, H.; Essl, F.; Dawson, W.; Fuentes, N.; Moser, D.; Pergl, Jan; Pyšek, Petr; van Kleunen, M.; Weber, E.; Winter, M.; Blasius, B.

    2015-01-01

    Roč. 21, č. 11 (2015), s. 4128-4140 ISSN 1354-1013 R&D Projects: GA ČR GB14-36079G; GA ČR(CZ) GAP504/11/1028 Grant - others:AV ČR(CZ) AP1002 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985939 Keywords : plant invasions * climate change * trade Subject RIV: EH - Ecology, Behaviour Impact factor: 8.444, year: 2015

  7. Global Invader Impact Network (GIIN): toward standardized evaluation of the ecological impacts of invasive plants

    Czech Academy of Sciences Publication Activity Database

    Barney, J. N.; Tekiela, D. R.; Barrios-Garcia, M. N.; Dimarco, R. D.; Hufbauer, R. A.; Leipzig-Scott, P.; Nunez, M. A.; Pauchard, A.; Pyšek, Petr; Vítková, Michaela; Maxwell, B. D.

    2015-01-01

    Roč. 5, č. 14 (2015), s. 2878-2889 ISSN 2045-7758 R&D Projects: GA ČR(CZ) GAP505/11/1112 Grant - others:AV ČR(CZ) AP1002 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985939 Keywords : invasive plants * coordinated distributed experiment * impact assessment Subject RIV: EH - Ecology, Behaviour Impact factor: 2.537, year: 2015

  8. Invasive plant architecture alters trophic interactions by changing predator abundance and behavior.

    Science.gov (United States)

    Pearson, Dean E

    2009-03-01

    As primary producers, plants are known to influence higher trophic interactions by initiating food chains. However, as architects, plants may bypass consumers to directly affect predators with important but underappreciated trophic ramifications. Invasion of western North American grasslands by the perennial forb, spotted knapweed (Centaurea maculosa), has fundamentally altered the architecture of native grassland vegetation. Here, I use long-term monitoring, observational studies, and field experiments to document how changes in vegetation architecture have affected native web spider populations and predation rates. Native spiders that use vegetation as web substrates were collectively 38 times more abundant in C. maculosa-invaded grasslands than in uninvaded grasslands. This increase in spider abundance was accompanied by a large shift in web spider community structure, driven primarily by the strong response of Dictyna spiders to C. maculosa invasion. Dictyna densities were 46-74 times higher in C. maculosa-invaded than native grasslands, a pattern that persisted over 6 years of monitoring. C. maculosa also altered Dictyna web building behavior and foraging success. Dictyna webs on C. maculosa were 2.9-4.0 times larger and generated 2.0-2.3 times higher total prey captures than webs on Achillea millefolium, their primary native substrate. Dictyna webs on C. maculosa also captured 4.2 times more large prey items, which are crucial for reproduction. As a result, Dictyna were nearly twice as likely to reproduce on C. maculosa substrates compared to native substrates. The overall outcome of C. maculosa invasion and its transformative effects on vegetation architecture on Dictyna density and web building behavior were to increase Dictyna predation on invertebrate prey >/=89 fold. These results indicate that invasive plants that change the architecture of native vegetation can substantially impact native food webs via nontraditional plant --> predator --> consumer

  9. Recognition of pyrrolizidine alkaloid esters in the invasive aquatic plant Gymnocoronis spilanthoides (Asteraceae).

    Science.gov (United States)

    Boppré, Michael; Colegate, Steven M

    2015-01-01

    The freshwater aquatic plant Gymnocoronis spilanthoides (Senegal tea plant, jazmín del bañado, Falscher Wasserfreund) is an invasive plant in many countries. Behavioural observations of pyrrolizidine alkaloid-pharmacophagous butterflies suggested the presence of pyrrolizidine alkaloids in the plant. To determine whether the attraction of the butterflies to the plant is an accurate indicator of pyrrolizidine alkaloids in G. spilanthoides. The alkaloid fraction of a methanolic extract of G. spilanthoides was analysed using HPLC with electrospray ionisation MS and MS/MS. Two HPLC approaches were used, that is, a C18 reversed-phase column with an acidic mobile phase, and a porous graphitic carbon column with a basic mobile phase. Pyrrolizidine alkaloids were confirmed, with the free base forms more prevalent than the N-oxides. The major alkaloids detected were lycopsamine and intermedine. The porous graphitic carbon HPLC column, with basic mobile phase conditions, resulted in better resolution of more pyrrolizidine alkaloids including rinderine, the heliotridine-based epimer of intermedine. Based on the MS/MS and high-resolution MS data, gymnocoronine was tentatively identified as an unusual C9 retronecine ester with 2,3-dihydroxy-2-propenylbutanoic acid. Among several minor-abundance monoester pyrrolizidines recognised, spilanthine was tentatively identified as an ester of isoretronecanol with the unusual 2-acetoxymethylbutanoic acid. The butterflies proved to be reliable indicators for the presence of pro-toxic 1,2-dehydropyrrolizidine alkaloids in G. spilanthoides, the first aquatic plant shown to produce these alkaloids. The presence of the anti-herbivory alkaloids may contribute to the plant's invasive capabilities and would certainly be a consideration in any risk assessment of deliberate utilisation of the plant. The prolific growth of the plant and the structural diversity of its pyrrolizidine alkaloids may make it ideal for investigating biosynthetic

  10. Improved Predictions of the Geographic Distribution of Invasive Plants Using Climatic Niche Models

    Science.gov (United States)

    Ramírez-Albores, Jorge E.; Bustamante, Ramiro O.

    2016-01-01

    Climatic niche models for invasive plants are usually constructed with occurrence records taken from literature and collections. Because these data neither discriminate among life-cycle stages of plants (adult or juvenile) nor the origin of individuals (naturally established or man-planted), the resulting models may mispredict the distribution ranges of these species. We propose that more accurate predictions could be obtained by modelling climatic niches with data of naturally established individuals, particularly with occurrence records of juvenile plants because this would restrict the predictions of models to those sites where climatic conditions allow the recruitment of the species. To test this proposal, we focused on the Peruvian peppertree (Schinus molle), a South American species that has largely invaded Mexico. Three climatic niche models were constructed for this species using high-resolution dataset gathered in the field. The first model included all occurrence records, irrespective of the life-cycle stage or origin of peppertrees (generalized niche model). The second model only included occurrence records of naturally established mature individuals (adult niche model), while the third model was constructed with occurrence records of naturally established juvenile plants (regeneration niche model). When models were compared, the generalized climatic niche model predicted the presence of peppertrees in sites located farther beyond the climatic thresholds that naturally established individuals can tolerate, suggesting that human activities influence the distribution of this invasive species. The adult and regeneration climatic niche models concurred in their predictions about the distribution of peppertrees, suggesting that naturally established adult trees only occur in sites where climatic conditions allow the recruitment of juvenile stages. These results support the proposal that climatic niches of invasive plants should be modelled with data of

  11. Woody structure facilitates invasion of woody plants by providing perches for birds.

    Science.gov (United States)

    Prather, Chelse M; Huynh, Andrew; Pennings, Steven C

    2017-10-01

    Woody encroachment threatens prairie ecosystems globally, and thus understanding the mechanisms that facilitate woody encroachment is of critical importance. Coastal tallgrass prairies along the Gulf Coast of the US are currently threatened by the spread of several species of woody plants. We studied a coastal tallgrass prairie in Texas, USA, to determine if existing woody structure increased the supply of seeds from woody plants via dispersal by birds. Specifically, we determined if (i) more seedlings of an invasive tree ( Tridacia sebifera ) are present surrounding a native woody plant ( Myrica cerifera ); (ii) wooden perches increase the quantity of seeds dispersed to a grassland; and (iii) perches alter the composition of the seed rain seasonally in prairie habitats with differing amounts of native and invasive woody vegetation, both underneath and away from artificial wooden perches. More T. sebifera seedlings were found within M. cerifera patches than in graminoid-dominated areas. Although perches did not affect the total number of seeds, perches changed the composition of seed rain to be less dominated by grasses and forbs. Specifically, 20-30 times as many seeds of two invasive species of woody plants were found underneath perches independent of background vegetation, especially during months when seed rain was highest. These results suggest that existing woody structure in a grassland can promote further woody encroachment by enhancing seed dispersal by birds. This finding argues for management to reduce woody plant abundance before exotic plants set seeds and argues against the use of artificial perches as a restoration technique in grasslands threatened by woody species.

  12. Unprecedented carbon accumulation in mined soils: the synergistic effect of resource input and plant species invasion.

    Science.gov (United States)

    Silva, Lucas C R; Corrêa, Rodrigo S; Doane, Timothy A; Pereira, Engil I P; Horwath, William R

    2013-09-01

    Opencast mining causes severe impacts on natural environments, often resulting in permanent damage to soils and vegetation. In the present study we use a 14-year restoration chronosequence to investigate how resource input and spontaneous plant colonization promote the revegetation and reconstruction of mined soils in central Brazil. Using a multi-proxy approach, combining vegetation surveys with the analysis of plant and soil isotopic abundances (delta13C and delta15N) and chemical and physical fractionation of organic matter in soil profiles, we show that: (1) after several decades without vegetation cover, the input of nutrient-rich biosolids into exposed regoliths prompted the establishment of a diverse plant community (> 30 species); (2) the synergistic effect of resource input and plant colonization yielded unprecedented increases in soil carbon, accumulating as chemically stable compounds in occluded physical fractions and reaching much higher levels than observed in undisturbed ecosystems; and (3) invasive grasses progressively excluded native species, limiting nutrient availability, but contributing more than 65% of the total accumulated soil organic carbon. These results show that soil-plant feedbacks regulate the amount of available resources, determining successional trajectories and alternative stable equilibria in degraded areas undergoing restoration. External inputs promote plant colonization, soil formation, and carbon sequestration, at the cost of excluding native species. The introduction of native woody species would suppress invasive grasses and increase nutrient availability, bringing the system closer to its original state. However, it is difficult to predict whether soil carbon levels could be maintained without the exotic grass cover. We discuss theoretical and practical implications of these findings, describing how the combination of resource manipulation and management of invasive species could be used to optimize restoration strategies

  13. A review of the influence of root-associating fungi and root exudates on the success of invasive plants

    Directory of Open Access Journals (Sweden)

    Cindy Bongard

    2012-08-01

    Full Text Available Plant-fungal interactions are essential for understanding the distribution and abundance of plants species. Recently, arbuscular mycorrhizal fungal (AMF partners of non-indigenous invasive plants have been hypothesized to be a critical factor influencing the invasion processes. AMF are known to improve nutrient and moisture uptake, as well as disrupt parasitic and pathogenic microbes in the host plant. Such benefits may enable invaders to establish significant and persistent populations in environments previously dominated by natives. Coupling these findings with studies on invader pathogen-disrupting root exudates is not well documented in the literature describing plant invasion strategies. The interaction effects of altered AMF associations and the impact of invader root exudates would be more relevant than understanding the AMF dynamics or the phytochemistry of successful invaders in isolation, particularly given that AMF and root exudates can have a similar role in pathogen control but function quite differently. One means to achieve this goal is to assess these strategies concurrently by characterizing both the general (mostly pathogens or commensals and AM-specific fungal colonization patterns found in field collected root samples of successful invaders, native plants growing within dense patches of invaders, and native plants growing separately from invaders. In this review I examine the emerging evidence of the ways in which AMF-plant interactions and the production of defensive root exudates provide pathways to invasive plant establishment and expansion, and conclude that interaction studies must be pursued to achieve a more comprehensive understanding of successful plant invasion.

  14. Invasion of Opuntia humifusa and O. phaeacantha (Cactaceae into plant communities of the Karadag Nature Reserve

    Directory of Open Access Journals (Sweden)

    Valentina V. Fateryga

    2017-11-01

    Full Text Available The results of a study of Opuntia humifusa and O. phaeacantha naturalised in the Karadag Nature Reserve (southeastern part of the Crimean Peninsula are presented. There, the largest coenopopulations of Opuntia plants are confined to the «biostation» territory (bordering with the park, administrative buildings and housing estate. Twelve localities were described in the Karadag Reserve. These differ by phytocoenotic characteristics, area and floristic composition. Seven localities include only O. humifusa plants; four ones include only O. phaeacantha individuals; and both the species are present on the twelfth locality. The total number of individuals of each species and ontogenetic structure of the population were studied in each locality. The total number of O. humifusa individuals in the Karadag Reserve is more than 600 plants within the «biostation» territory, while the total number of O. phaeacantha plants is about 400 individuals. Studying of the plant communities has been carried out according to the Braun-Blanquet method. Opuntia plants form derivate communities within degraded steppes, phryganoid-steppes, and semi-desert badland phytocoenoses almost at all studied localities. A significant number of synanthropic species (including alien plants was found within these communities. Opuntia plants are able to self-reproduce predominantly vegetatively. Self-seeding reproduction occurs less frequently. Both species can be considered as invasive plants because they have a high adaptive capacity.

  15. Invasive grasses change landscape structure and fire behavior in Hawaii

    Science.gov (United States)

    Lisa M. Ellsworth; Creighton M. Litton; Alexander P. Dale; Tomoaki Miura

    2014-01-01

    How does potential fire behavior differ in grass-invaded non-native forests vs open grasslands? How has land cover changed from 1950–2011 along two grassland/forest ecotones in Hawaii with repeated fires? A study on non-native forest with invasive grass understory and invasive grassland (Megathyrsus maximus) ecosystems on Oahu, Hawaii, USA was...

  16. Invasive pests—insects and diseases

    Science.gov (United States)

    Donald A. Duerr; Paul A. Mistretta

    2013-01-01

    Key FindingsNonnative pest species have increasing impacts in the South regardless of climate change, patterns of land ownership, or changes in the composition of vegetation.“New” nonnative invasive insects and diseases will have serious impacts on southern forests over the next 50 years. Some species such as emerald ash borer...

  17. Effects of an invasive plant on a desert sand dune landscape

    Science.gov (United States)

    Barrows, C.W.; Allen, E.B.; Brooks, M.L.; Allen, M.F.

    2009-01-01

    Given the abundance of non-native species invading wildland habitats, managers need to employ informed triage to focus control efforts on weeds with the greatest potential for negative impacts. Our objective here was to determine the level of threat Sahara mustard, Brassica tournefortii, represents to meeting regional goals for protecting biodiversity. Sahara mustard has spread throughout much of the Mojave and lower Sonoran Deserts. It has occurred in southern California's Coachella Valley for nearly 80 years, punctuated by years of extremely high abundance following high rainfall. In those years the mustard has clear negative impacts on the native flora. Using mustard removal experiments we identified reductions in native plant reproduction, shifting composition increasingly toward Sahara mustard while decreasing the fraction of native species. High between-year variance in precipitation may be a key to maintaining biodiversity as the mustard is less abundant in drier years. Sahara mustard impacts to the native fauna were much less evident. Of the animal species evaluated, only the Coachella Valley fringe-toed lizard, Uma inornata, demonstrated a negative response to mustard abundance; however the impacts were short-lived, lasting no more than a year after the mustard's dominance waned. Without control measures the long-term impacts to desert biodiversity may rest on the changing climate. Wetter conditions or increased periodicity of high rainfall years will favor Sahara mustard and result in reduced biodiversity, especially of native annual plants. Drier conditions will keep the mustard from becoming dominant but may have other negative consequences on the native flora and fauna. ?? 2008 Springer Science+Business Media B.V.

  18. Do forest soil microbes have the potential to resist plant invasion? A case study in Dinghushan Biosphere Reserve (South China)

    Science.gov (United States)

    Chen, Bao-Ming; Li, Song; Liao, Hui-Xuan; Peng, Shao-Lin

    2017-05-01

    Successful invaders must overcome biotic resistance, which is defined as the reduction in invasion success caused by the resident community. Soil microbes are an important source of community resistance to plant invasions, and understanding their role in this process requires urgent investigation. Therefore, three forest communities along successional stages and four exotic invasive plant species were selected to test the role of soil microbes of three forest communities in resisting the exotic invasive plant. Our results showed that soil microbes from a monsoon evergreen broadleaf forest (MEBF) (late-successional stage) had the greatest resistance to the invasive plants. Only the invasive species Ipomoea triloba was not sensitive to the three successional forest soils. Mycorrhizal fungi in early successional forest Pinus massonina forest (PMF) or mid-successional forest pine-broadleaf mixed forest (PBMF) soil promoted the growth of Mikania micrantha and Eupatorium catarium, but mycorrhizal fungi in MEBF soil had no significant effects on their growth. Pathogens plus other non-mycorrhizal microbes in MEBF soil inhibited the growth of M. micrantha and E. catarium significantly, and only inhibited root growth of E. catarium when compared with those with mycorrhizal fungi addition. The study suggest that soil mycorrhizal fungi of early-mid-successional forests benefit invasive species M. micrantha and E. catarium, while soil pathogens of late-successional forest may play an important role in resisting M. micrantha and E. catarium. The benefit and resistance of the soil microbes are dependent on invasive species and related to forest succession. The study gives a possible clue to control invasive plants by regulating soil microbes of forest community to resist plant invasion.

  19. Identification of invasive and expansive plant species based on airborne hyperspectral and ALS data

    Science.gov (United States)

    Szporak-Wasilewska, Sylwia; Kuc, Gabriela; Jóźwiak, Jacek; Demarchi, Luca; Chormański, Jarosław; Marcinkowska-Ochtyra, Adriana; Ochtyra, Adrian; Jarocińska, Anna; Sabat, Anita; Zagajewski, Bogdan; Tokarska-Guzik, Barbara; Bzdęga, Katarzyna; Pasierbiński, Andrzej; Fojcik, Barbara; Jędrzejczyk-Korycińska, Monika; Kopeć, Dominik; Wylazłowska, Justyna; Woziwoda, Beata; Michalska-Hejduk, Dorota; Halladin-Dąbrowska, Anna

    2017-04-01

    The aim of Natura 2000 network is to ensure the long term survival of most valuable and threatened species and habitats in Europe. The encroachment of invasive alien and expansive native plant species is among the most essential threat that can cause significant damage to protected habitats and their biodiversity. The phenomenon requires comprehensive and efficient repeatable solutions that can be applied to various areas in order to assess the impact on habitats. The aim of this study is to investigate of the issue of invasive and expansive plant species as they affect protected areas at a larger scale of Natura 2000 network in Poland. In order to determine the scale of the problem we have been developing methods of identification of invasive and expansive species and then detecting their occurrence and mapping their distribution in selected protected areas within Natura 2000 network using airborne hyperspectral and airborne laser scanning data. The aerial platform used consists of hyperspectral HySpex scanner (451 bands in VNIR and SWIR), Airborne Laser Scanner (FWF) Riegl Lite Mapper and RGB camera. It allowed to obtain simultaneous 1 meter resolution hyperspectral image, 0.1 m resolution orthophotomaps and point cloud data acquired with 7 points/m2. Airborne images were acquired three times per year during growing season to account for plant seasonal change (in May/June, July/August and September/October 2016). The hyperspectral images were radiometrically, geometrically and atmospherically corrected. Atmospheric correction was performed and validated using ASD FieldSpec 4 measurements. ALS point cloud data were used to generate several different topographic, vegetation and intensity products with 1 m spatial resolution. Acquired data (both hyperspectral and ALS) were used to test different classification methods including Mixture Tuned Matched Filtering (MTMF), Spectral Angle Mapper (SAM), Random Forest (RF), Support Vector Machines (SVM), among others

  20. Invasion of a Legume Ecosystem Engineer in a Cold Biome Alters Plant Biodiversity

    Directory of Open Access Journals (Sweden)

    Vanessa M. S. Vetter

    2018-06-01

    Full Text Available Plant ecosystem engineers are widely used to combat land degradation. However, the ability of those plants to modulate limiting abiotic and biotic resources of other species can cause damage to ecosystems in which they become invasive. Here, we use Lupinus nootkatensis as example to estimate and project the hazardous potential of nitrogen fixing herbaceous plants in a sub-polar oceanic climate. L. nootkatensis was introduced to Iceland in the 1940s to address erosion problems and foster reforestation, but subsequently became a high-latitude invader. In a local field survey, we quantified the impact of L. nootkatensis invasion at three different cover levels (0, 10–50, and 51–100% upon native plant diversity, richness, and community composition of heath-, wood-, and grasslands using a pairwise comparison design and comparisons of means. Afterward, we scaled impacts up to the ecosystem and landscape level by relating occurrences of L. nootkatensis to environmental and human-mediated variables across Iceland using a species distribution model. Plant diversity was significantly deteriorated under high lupine cover levels of the heath- and woodland, but not in the grassland. Plant species richness of the most diverse habitat, the heathland, linearly decreased with lupine cover level. The abundance of small rosettes, cushion plants, orchids, and small woody long-lived plants of the heath declined with invader presence, while the abundance of late successional species and widespread nitrophilous ruderals in wood- and grasslands increased. Distribution modeling revealed 13.3% of Iceland’s land surface area to be suitable lupine habitat. Until 2061–2080, this area will more than double and expand significantly into the Central Highlands due to human mediation and increasingly favorable climatic conditions. Species-rich habitats showed a loss of plant species diversity and richness as well as a change in community composition even in low lupine

  1. Using long-term datasets to study exotic plant invasions on rangelands in the western United States

    Science.gov (United States)

    Invasions by exotic species are generally described with a logistic growth curve divided into three phases: introduction, expansion and saturation. This model is constructed primarily from regional studies of plant invasions based on historical records and herbarium samples. The goal of this study w...

  2. Alien plants introduced by different pathways differ in invasion success: unintentional introductions as a threat to natural areas

    Czech Academy of Sciences Publication Activity Database

    Pyšek, Petr; Jarošík, Vojtěch; Pergl, Jan

    2011-01-01

    Roč. 6, č. 9 (2011), e24890 E-ISSN 1932-6203 R&D Projects: GA MŠk LC06073; GA ČR(CZ) GAP504/11/1028 Institutional research plan: CEZ:AV0Z60050516 Keywords : plant invasions * pathways * naturalization and invasion Subject RIV: EF - Botanics Impact factor: 4.092, year: 2011

  3. Alien plant invasion in mixed-grass prairie: effects of vegetation type, stochiasticity, and anthropogenic disturbance in two park units

    Science.gov (United States)

    Larson, Diane L.; Anderson, Patrick J.; Newton, Wesley E.

    2001-01-01

    The ability of alien plant species to invade a region depends not only on attributes of the plant, but on characteristics of the habitat being invaded. Here, we examine characteristics that may influence the success of alien plant invasion in mixed-grass prairie at Theodore Roosevelt National Park, in western North Dakota, USA. The park consists of two geographically separate units with similar vegetation types and management history, which allowed us to examine the effects of native vegetation type, anthropogenic disturbance, and the separate park units on the invasion of native plant communities by alien plant species common to counties surrounding both park units. If matters of chance related to availability of propagules and transient establishment opportunities determine the success of invasion, park unit and anthropogenic disturbance should better explain the variation in alien plant frequency. If invasibility is more strongly related to biotic or physical characteristics of the native plant communities, models of alien plant occurrence should include vegetation type as an explanatory variable. We examined >1300 transects across all vegetation types in both units of the park. Akaike's Information Criterion (AIC) indicated that the fully parameterized model, including the interaction among vegetation type, disturbance, and park unit, best described the distribution of both total number of alien plants per transect and frequency of alien plants on transects where they occurred. Although all vegetation types were invaded by alien plants, mesic communities had both greater numbers and higher frequencies of alien plants than did drier communities. A strong element of stochasticity, reflected in differences in frequencies of individual species between the two park units, suggests that prediction of risk of invasion will always involve uncertainty. In addition, despite well-documented associations between anthropogenic disturbance and alien plant invasion, five of

  4. Pre-damage biomass allocation and not invasiveness predicts tolerance to damage in seedlings of woody species in Hawaii.

    Science.gov (United States)

    Lurie, Matthew H; Barton, Kasey E; Daehler, Curtis C

    2017-12-01

    Plant-herbivore interactions have been predicted to play a fundamental role in plant invasions, although support for this assertion from previous research is mixed. While plants may escape from specialist herbivores in their introduced ranges, herbivory from generalists is common. Tolerance traits may allow non-native plants to mitigate the negative consequences of generalist herbivory that they cannot avoid in their introduced range. Here we address whether tolerance to herbivory, quantified as survival and compensatory growth, is associated with plant invasion success in Hawaii and investigate traits that may enhance tolerance in seedlings, the life stage most susceptible to herbivory. In a greenhouse experiment, we measured seedling tolerance to simulated herbivory through mechanical damage (50% leaf removal) of 16 non-native woody plant species differing in invasion status (invasive vs. non-invasive). Seedlings were grown for 2 weeks following damage and analyzed for biomass to determine whether damaged plants could fully compensate for the lost leaf tissue. Over 99% of all seedlings survived defoliation. Although species varied significantly in their levels of compensation, there was no consistent difference between invasive and non-invasive species. Seedlings of 11 species undercompensated and remained substantially smaller than control seedlings 2 weeks after damage; four species were close to compensating, while one species overcompensated. Across species, compensation was positively associated with an increased investment in potential storage reserves, specifically cotyledons and roots, suggesting that these organs provide resources that help seedlings re-grow following damage. Our results add to a growing consensus that pre-damage growth patterns determine tolerance to damage, even in young seedlings which have relatively low biomass. The lack of higher tolerance in highly invasive species may suggest that invaders overcome herbivory barriers to invasion

  5. Shift in cytotype frequency and niche space in the invasive plant Centaurea maculosa.

    Science.gov (United States)

    Treier, Urs A; Broennimann, Olivier; Normand, Signe; Guisan, Antoine; Schaffner, Urs; Steinger, Thomas; Müller-Schärer, Heinz

    2009-05-01

    Polyploidy is often assumed to increase the spread and thus the success of alien plant species, but few empirical studies exist. We tested this hypothesis with Centaurea maculosa Lam., a species native to Europe and introduced into North America approximately 120 years ago where it became highly invasive. We analyzed the ploidy level of more than 2000 plants from 93 native and 48 invasive C. maculosa populations and found a pronounced shift in the relative frequency of diploid and tetraploid cytotypes. In Europe diploid populations occur in higher frequencies than tetraploids and only four populations had both cytotypes, while in North America diploid plants were found in only one mixed population and thus tetraploids clearly dominated. Our results showed a pronounced shift in the climatic niche between tetraploid populations in the native and introduced range toward drier climate in North America and a similar albeit smaller shift between diploids and tetraploids in the native range. The field data indicate that diploids have a predominately monocarpic life cycle, while tetraploids are often polycarpic. Additionally, the polycarpic life-form seems to be more prevalent among tetraploids in the introduced range than among tetraploids in the native range. Our study suggests that both ploidy types of C. maculosa were introduced into North America, but tetraploids became the dominant cytotype with invasion. We suggest that the invasive success of C. maculosa is partly due to preadaptation of the tetraploid cytotype in Europe to drier climate and possibly further adaptation to these conditions in the introduced range. The potential for earlier and longer seed production associated with the polycarpic life cycle constitutes an additional factor that may have led to the dominance of tetraploids over diploids in the introduced range.

  6. The economics of landscape restoration: Benefits of controlling bush encroachment and invasive plant species in South Africa and Namibia

    CSIR Research Space (South Africa)

    Stafford, William

    2017-01-01

    Full Text Available Bush encroachment and alien plant invasions alter the composition and/or balance of species in natural ecosystems and impact biodiversity, land productivity and water availability. Therefore, the appropriate control and management of bush...

  7. Effects of metal lead on growth and mycorrhizae of an invasive plant species (Solidago canadensis L.).

    Science.gov (United States)

    Yang, Ruyi; Yu, Guodong; Tang, Jianjun; Chen, Xin

    2008-01-01

    It is less known whether and how soil metal lead (Pb) impacts the invasion of exotic plants. A greenhouse experiment was conducted to estimate the effects of lead on the growth and mycorrhizae of an invasive species (Solidago canadensis L.) in a microcosm system. Each microcosm unit was separated into HOST and TEST compartments by a replaceable mesh screen that allowed arbuscular mycorrhizal (AM) fungal hyphae rather than plant roots to grow into the TEST compartments. Three Pb levels (control, 300, and 600 mg/kg soil) were used in this study to simulate ambient soil and two pollution sites where S. canadensis grows. Mycorrhizal inoculum comprised five indigenous arbuscular mycorrhizal fungal species (Glomus mosseae, Glomus versiform, Glomus diaphanum, Glomus geosporum, and Glomus etunicatum). The 15N isotope tracer was used to quantify the mycorrhizally mediated nitrogen acquisition of plants. The results showed that S. canadensis was highly dependent on mycorrhizae. The Pb additions significantly decreased biomass and arbuscular mycorrhizal colonization (root length colonized, RLC%) but did not affect spore numbers, N (including total N and 15N) and P uptake. The facilitating efficiency of mycorrhizae on nutrient acquisition was promoted by Pb treatments. The Pb was mostly sequestered in belowground of plant (root and rhizome). The results suggest that the high efficiency of mycorrhizae on nutrient uptake might give S. canadensis a great advantage over native species in Pb polluted soils.

  8. Shrubs as ecosystem engineers across an environmental gradient: effects on species richness and exotic plant invasion.

    Science.gov (United States)

    Kleinhesselink, Andrew R; Magnoli, Susan M; Cushman, J Hall

    2014-08-01

    Ecosystem-engineering plants modify the physical environment and can increase species diversity and exotic species invasion. At the individual level, the effects of ecosystem engineers on other plants often become more positive in stressful environments. In this study, we investigated whether the community-level effects of ecosystem engineers also become stronger in more stressful environments. Using comparative and experimental approaches, we assessed the ability of a native shrub (Ericameria ericoides) to act as an ecosystem engineer across a stress gradient in a coastal dune in northern California, USA. We found increased coarse organic matter and lower wind speeds within shrub patches. Growth of a dominant invasive grass (Bromus diandrus) was facilitated both by aboveground shrub biomass and by growing in soil taken from shrub patches. Experimental removal of shrubs negatively affected species most associated with shrubs and positively affected species most often found outside of shrubs. Counter to the stress-gradient hypothesis, the effects of shrubs on the physical environment and individual plant growth did not increase across the established stress gradient at this site. At the community level, shrub patches increased beta diversity, and contained greater rarified richness and exotic plant cover than shrub-free patches. Shrub effects on rarified richness increased with environmental stress, but effects on exotic cover and beta diversity did not. Our study provides evidence for the community-level effects of shrubs as ecosystem engineers in this system, but shows that these effects do not necessarily become stronger in more stressful environments.

  9. Effect of plant species richness on weed invasion in experimental plant communities

    Czech Academy of Sciences Publication Activity Database

    Lanta, Vojtěch; Lepš, Jan

    2008-01-01

    Roč. 198, č. 2 (2008), s. 253-263 ISSN 1385-0237 R&D Projects: GA ČR GD206/03/H034; GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60050516; CEZ:AV0Z50070508 Keywords : Biodiversity * Invasion * Weeds Subject RIV: EF - Botanics Impact factor: 1.730, year: 2008

  10. The role of habitat factors in successful invasion of alien plant Acer negundo in riparian zones.

    Science.gov (United States)

    Sikorski, Piotr; Sikorska, Daria

    2016-04-01

    Ash-leaved maple (Acer negundo) is one of the most invasive species occurring in riparian zones. The invasion is especially effective in disturbed areas, as the plant favours anthropogenic sites. The plant was also observed to be able to penetrate into sandy bars, also those separated from the land, inaccessible to people. It's removal is time-consuming and laborious, often involves damage done to sensitive vegetation and the results are doubtful, as the plant quickly regenerates. The invasion patterns and establishment of ash-leaved maple in natural ecosystems are poorly investigated. The aim of this study was to test how habitat factors such as: light availability, soil characteristics and competition contribute to ash-leaved maple effective colonization of natural sand bars free from anthropogenic pressure. In 2014 sand bars located in Vistula River Valley in Warsaw were inventoried and classified basing on their development stage as 1 - initial, 2 - unstable, 3 - stable. Apart from the occurrence of the invasive ash-leaved maple the plants competing with it were recognized and the percentage of the shoots of shrubs and herbaceous plants was estimated. PAR was measured at ground level and 1 meter above ground, the thickness of organic layer formed on the top of the sand was also measured as the indicator of sand bar development stage. The maple's survival in extremely difficult conditions resembles the strategy of willows and poplars naturally occurring in the riparian zones, which are well adapted to this environment. The success of invasion strongly depends on the plants establishment during sand bars initial stage of development. The seedlings growth correlates with the age of the sand bar (r1=0,41, r2=0,42 i r3=0,57). The colonization lasts for 4-6 years and the individuals start to cluster in bigger parches. After that period the maple turns into the phase of competition for space. Habitat factors such as shading (r2=0,41 i r3=0,51) and organic layer

  11. Using soil seed banks to assess temporal patterns of genetic variation in invasive plant populations.

    Science.gov (United States)

    Fennell, Mark; Gallagher, Tommy; Vintro, Luis Leon; Osborne, Bruce

    2014-05-01

    Most research on the genetics of invasive plant species has focused on analyzing spatial differences among existing populations. Using a long-established Gunnera tinctoria population from Ireland, we evaluated the potential of using plants derived from seeds associated with different soil layers to track genetic variation through time. This species and site were chosen because (1) G. tinctoria produces a large and persistent seed bank; (2) it has been present in this locality, Sraheens, for ∼90 years; (3) the soil is largely undisturbed; and (4) the soil's age can be reliably determined radiometrically at different depths. Amplified fragment length polymorphic markers (AFLPs) were used to assess differences in the genetic structure of 75 individuals sampled from both the standing population and from four soil layers, which spanned 18 cm (estimated at ∼90 years based on (210)Pb and (137)Cs dating). While there are difficulties in interpreting such data, including accounting for the effects of selection, seed loss, and seed migration, a clear pattern of lower total allele counts, percentage polymorphic loci, and genetic diversity was observed in deeper soils. The greatest percentage increase in the measured genetic variables occurred prior to the shift from the lag to the exponential range expansion phases and may be of adaptive significance. These findings highlight that seed banks in areas with long-established invasive populations can contain valuable genetic information relating to invasion processes and as such, should not be overlooked.

  12. The invasive alien plants threatened the balance of ecosystem in conservative area in Ontoloe Island, Flores-Indonesia

    Science.gov (United States)

    Antonius Mboka Segu Wake, Ignatius; Retnaningsih Soeprobowati, Tri; Jumari

    2018-05-01

    Invasive alien plants threaten to biodiversity, particularly in small island with high endemicity values such as Ontoloe Island, a tourist destination area of Riung Seventeen Island in Flores. The study aims to characterized the invasive plants have attacked the conservative area in Ontoloe Island. The method used by combining the line method and the plot method with three observation stations in utilization block and four observation station in protection block. Plot of 1mx1m was used for the observation of ground cover plants and seedling, 5mx5m for the observation in stake level, 10mx10m for the observation in pole level, 20mx20m for the observation in tree level. The data level of the plants obtained then analyzed with Important Value Index (IVI). Result showed that Lamtoro plants (Leuchaena leucocephala) is the invasive alien species which has the highest IVI in both of utilization block and protection block in each level of tree, stake, and pole. There are other invasive alien plants such as Tembeleken (Lantana camara) and Bidara (Zizipus mauritiana) dominated in stake level and Alang-alang (Imperata cylindrica) dominated in seedling level. All the native plants in Ontoloe Island will be threatened their existing because of the less control of invasive alien plants. Therefore, needs serious handling by the government in order to keep the balanced of the ecosystems in Ontoloe Island to be maintained especially to not deviated from management objectives area of Komodo Dragons conservation (Varanus komodoensis Ouwens, 1912).

  13. Estimating suitable environments for invasive plant species across large landscapes: a remote sensing strategy using Landsat 7 ETM+

    Science.gov (United States)

    Young, Kendal E.; Abbott, Laurie B.; Caldwell, Colleen A.; Schrader, T. Scott

    2013-01-01

    The key to reducing ecological and economic damage caused by invasive plant species is to locate and eradicate new invasions before they threaten native biodiversity and ecological processes. We used Landsat Enhanced Thematic Mapper Plus imagery to estimate suitable environments for four invasive plants in Big Bend National Park, southwest Texas, using a presence-only modeling approach. Giant reed (Arundo donax), Lehmann lovegrass (Eragrostis lehmanniana), horehound (Marrubium vulgare) and buffelgrass (Pennisteum ciliare) were selected for remote sensing spatial analyses. Multiple dates/seasons of imagery were used to account for habitat conditions within the study area and to capture phenological differences among targeted species and the surrounding landscape. Individual species models had high (0.91 to 0.99) discriminative ability to differentiate invasive plant suitable environments from random background locations. Average test area under the receiver operating characteristic curve (AUC) ranged from 0.91 to 0.99, indicating that plant predictive models exhibited high discriminative ability to differentiate suitable environments for invasive plant species from random locations. Omission rates ranged from <1.0 to 18%. We demonstrated that useful models estimating suitable environments for invasive plants may be created with <50 occurrence locations and that reliable modeling using presence-only datasets can be powerful tools for land managers.

  14. Quantitative economic impact assessment of an invasive plant disease under uncertainty - a case study for potato spindle tuber viroid (PSTVd) invasion into the European Union

    NARCIS (Netherlands)

    Soliman, T.; Mourits, M.C.M.; Oude Lansink, A.G.J.M.; Werf, van der W.

    2012-01-01

    International treaties require that phytosanitary measures against introduction and spread of invasive plant pests are justified by a science-based pest risk analysis, including an assessment of potential economic consequences. This study evaluates the economic justification of the currently applied

  15. Parallel evolution in an invasive plant species : evolutionary changes in allocation to growth, defense, competitive ability and regrowth of invasive Jacobaea vulgaris

    NARCIS (Netherlands)

    Lin, Tiantian

    2015-01-01

    Although the introduction of invasive plant species in a given area causes economic and ecological problems, it still provides an ideal opportunity for ecologists to study evolutionary changes. According to the Evolution of Increased Competitive Ability hypothesis and Shifting Defense Hypothesis,

  16. Explaining the variation in impacts of non-native plants on local-scale species richness: the role of phylogenetic relatedness

    Czech Academy of Sciences Publication Activity Database

    Vila, M.; Rohr, R. P.; Espinar, J. L.; Hulme, P. E.; Pergl, Jan; Le Roux, J. J.; Schaffner, U.; Pyšek, Petr

    2015-01-01

    Roč. 24, č. 2 (2015), s. 139-146 ISSN 1466-822X R&D Projects: GA ČR(CZ) GAP505/11/1112; GA ČR(CZ) GAP504/11/1028 Grant - others:AV ČR(CZ) AP1002 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985939 Keywords : biological invasions * impact * metaanalysis Subject RIV: EH - Ecology, Behaviour Impact factor: 5.840, year: 2015

  17. Antioxidant activity of an invasive plant, Melastoma malabathricum and its potential as herbal tea product

    Science.gov (United States)

    Sari, N. M.; Kuspradini, H.; Amirta, R.; Kusuma, I. W.

    2018-04-01

    East Kalimantan possesses abundant biodiversity of tropical medicinal plant. Melastoma malabathricum (known locally as karamunting, senduduk) is an invasive plant along with other species in the family of Melastomataceae with traditional medicinal purposes. This research explored the potential of Karamunting (M. malabathricum) plant for its antioxidant activity and the potential as a material for herbal tea product. The plant was macerated to yield ethanolic extract, and at the same time plant powder was packed into tea bags and extracted with hot water to obtain the infused water. Antioxidant activity was evaluated by DPPH radical scavenging assay. The results showed that the ethanol extracts of plant samples displayed ability to inhibit DPPH free radical formation by 82% at 50 ppm concentration. Evaluation of the tea water extract showed that the highest inhibition obtained by leaves powder by 90% and fruit 88% at 1 minutes immersion time. This finding suggest that leaves and fruit of M. malabathricum plants display potential as herbal tea material having antioxidant activity if the safety aspect can be assured.

  18. Stakeholder Perceptions of an Ecosystem Services Approach to Clearing Invasive Alien Plants on Private Land

    Directory of Open Access Journals (Sweden)

    Lauren S. Urgenson

    2013-03-01

    Full Text Available Incentivizing private landowners and other stakeholders is central to the effective conservation of ecosystem services in working landscapes. To better understand how to design effective incentives, the perceptions of landowners and other stakeholders are explored regarding a proposed approach to clearing invasive alien plants on private land in the Western Cape Province, South Africa. The public funded national program, Working for Water, conserves ecosystem services while employing and training people from marginalized sectors of society to clear these plants. Private landowner involvement is a key conservation challenge, because without adequate landowner involvement, invasive alien plants persist on the landscape and continuously reinvade cleared areas. We collected interview data from private landowners in three study sites, and web-survey data from conservation professionals and Working for Water managers, in order to compare stakeholder perceptions of (1 government and landowners' responsibilities for clearing invasive alien plants; (2 existing and proposed policy tools; and (3 the extent to which stakeholders consider the proposed financial incentive to be sufficient. There was significant consensus among stakeholders concerning their preference for shared landowner and government responsibility and for a policy mix that combines incentives with disincentives. Landowners from the three study sites differed in the level of responsibility they were willing to assume. Stakeholders also diverged in terms of their perceptions of the proposed financial incentives. Furthermore, the perspectives of landowners were strongly associated with ecological and social features of the landscapes in which they are located. Understanding stakeholders' points of view within their differing contexts is shown to be a valuable means of gaining insight into the opportunities and constraints that face ecosystem service conservation in working landscapes.

  19. Human disturbance and upward expansion of plants in a warming climate

    Science.gov (United States)

    Dainese, Matteo; Aikio, Sami; Hulme, Philip E.; Bertolli, Alessio; Prosser, Filippo; Marini, Lorenzo

    2017-08-01

    Climate change is expected to trigger an upward expansion of plants in mountain regions and, although there is strong evidence that many native species have already shifted their distributions to higher elevations, little is known regarding how fast non-native species might respond to climate change. By analysing 131,394 occurrence records of 1,334 plant species collected over 20 years in the European Alps, we found that non-natives are spreading upwards approximately twice as fast as natives. Whereas the spread of natives was enhanced by traits favouring longer dispersal distances, this was not the case for non-natives. This was due to the non-native species pool already being strongly biased towards species that had traits facilitating spread. A large proportion of native and non-native species seemed to be able to spread upwards faster than the current velocity of climate change. In particular, long-distance dispersal events and proximity to roads proved to be key drivers for the observed rapid spread. Our findings highlight that invasions by non-native species into native alpine communities are a potentially significant additional pressure on these vulnerable ecosystems that are already likely to suffer dramatic vegetation changes with ongoing warming and increasing human activity in mountain regions.

  20. Meta-analysis reveals evolution in invasive plant species but little support for Evolution of Increased Competitive Ability (EICA).

    Science.gov (United States)

    Felker-Quinn, Emmi; Schweitzer, Jennifer A; Bailey, Joseph K

    2013-03-01

    Ecological explanations for the success and persistence of invasive species vastly outnumber evolutionary hypotheses, yet evolution is a fundamental process in the success of any species. The Evolution of Increased Competitive Ability (EICA) hypothesis (Blossey and Nötzold 1995) proposes that evolutionary change in response to release from coevolved herbivores is responsible for the success of many invasive plant species. Studies that evaluate this hypothesis have used different approaches to test whether invasive populations allocate fewer resources to defense and more to growth and competitive ability than do source populations, with mixed results. We conducted a meta-analysis of experimental tests of evolutionary change in the context of EICA. In contrast to previous reviews, there was no support across invasive species for EICA's predictions regarding defense or competitive ability, although invasive populations were more productive than conspecific native populations under noncompetitive conditions. We found broad support for genetically based changes in defense and competitive plant traits after introduction into new ranges, but not in the manner suggested by EICA. This review suggests that evolution occurs as a result of plant introduction and population expansion in invasive plant species, and may contribute to the invasiveness and persistence of some introduced species.

  1. Effects of soil nutrient heterogeneity on intraspecific competition in the invasive, clonal plant Alternanthera philoxeroides.

    Science.gov (United States)

    Zhou, Jian; Dong, Bi-Cheng; Alpert, Peter; Li, Hong-Li; Zhang, Ming-Xiang; Lei, Guang-Chun; Yu, Fei-Hai

    2012-03-01

    Fine-scale, spatial heterogeneity in soil nutrient availability can increase the growth of individual plants, the productivity of plant communities and interspecific competition. If this is due to the ability of plants to concentrate their roots where nutrient levels are high, then nutrient heterogeneity should have little effect on intraspecific competition, especially when there are no genotypic differences between individuals in root plasticity. We tested this hypothesis in a widespread, clonal species in which individual plants are known to respond to nutrient heterogeneity. Plants derived from a single clone of Alternanthera philoxeroides were grown in the greenhouse at low or high density (four or 16 plants per 27·5 × 27·5-cm container) with homogeneous or heterogeneous availability of soil nutrients, keeping total nutrient availability per container constant. After 9 weeks, measurements of size, dry mass and morphology were taken. Plants grew more in the heterogeneous than in the homogeneous treatment, showing that heterogeneity promoted performance; they grew less in the high- than in the low-density treatment, showing that plants competed. There was no interactive effect of nutrient heterogeneity and plant density, supporting the hypothesis that heterogeneity does not affect intraspecific competition in the absence of genotypic differences in plasticity. Treatments did not affect morphological characteristics such as specific leaf area or root/shoot ratio. Results indicate that fine-scale, spatial heterogeneity in the availability of soil nutrients does not increase competition when plants are genetically identical, consistent with the suggestion that effects of heterogeneity on competition depend upon differences in plasticity between individuals. Heterogeneity is only likely to increase the spread of monoclonal, invasive populations such as that of A. philoxeroides in China.

  2. Restoration ecology and invasive riparian plants: An introduction to the special section on Tamarix spp. in western North America

    Science.gov (United States)

    Shafroth, Patrick B.; Briggs, Mark K.

    2008-01-01

    River systems around the world are subject to various perturbations, including the colonization and spread of non-native species in riparian zones. Riparian resource managers are commonly engaged in efforts to control problematic non-native species and restore native habitats. In western North America, small Eurasian trees or shrubs in the genus Tamarixoccupy hundreds of thousands of hectares of riparian lands, and are the targets of substantial and costly control efforts and associated restoration activities. Still, significant information gaps exist regarding approaches used in control and restoration efforts and their effects on riparian ecosystems. In this special section of papers, eight articles address various aspects of control and restoration associated with Tamarix spp. These include articles focused on planning restoration and revegetation; a synthetic analysis of past restoration efforts; and several specific research endeavors examining plant responses, water use, and various wildlife responses (including birds, butterflies, and lizards). These articles represent important additions to the Tamarix spp. literature and contain many lessons and insights that should be transferable to other analogous situations in river systems globally.

  3. Legume-rhizobium symbiotic promiscuity and effectiveness do not affect plant invasiveness.

    Science.gov (United States)

    Keet, Jan-Hendrik; Ellis, Allan G; Hui, Cang; Le Roux, Johannes J

    2017-06-01

    The ability to fix atmospheric nitrogen is thought to play an important role in the invasion success of legumes. Interactions between legumes and nitrogen-fixing bacteria (rhizobia) span a continuum of specialization, and promiscuous legumes are thought to have higher chances of forming effective symbioses in novel ranges. Using Australian Acacia species in South Africa, it was hypothesized that widespread and highly invasive species will be more generalist in their rhizobial symbiotic requirements and more effective in fixing atmospheric nitrogen compared with localized and less invasive species. To test these hypotheses, eight localized and 11 widespread acacias were examined using next-generation sequencing data for the nodulation gene, nodC , to compare the identity, species richness, diversity and compositional similarity of rhizobia associated with these acacias. Stable isotope analysis was also used to determine levels of nitrogen obtained from the atmosphere via symbiotic nitrogen fixation. No differences were found in richness, diversity and community composition between localized and widespread acacias. Similarly, widespread and localized acacias did not differ in their ability to fix atmospheric nitrogen. However, for some species by site comparisons, significant differences in δ15N isotopic signatures were found, indicating differential symbiotic effectiveness between these species at specific localities. Overall, the results support recent findings that root nodule rhizobial diversity and community composition do not differ between acacias that vary in their invasiveness. Differential invasiveness of acacias in South Africa is probably linked to attributes such as differences in propagule pressure, reasons for (e.g. forestry vs. ornamental) and extent of, plantings in the country. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  4. Invasive species management restores a plant-pollinator mutualism in Hawaii

    Science.gov (United States)

    Hanna, Cause; Foote, David; Kremen, Claire

    2013-01-01

    1.The management and removal of invasive species may give rise to unanticipated changes in plant–pollinator mutualisms because they can alter the composition and functioning of plant–pollinator interactions in a variety of ways. To utilize a functional approach for invasive species management, we examined the restoration of plant–pollinator mutualisms following the large-scale removal of an invasive nectar thief and arthropod predator, Vespula pensylvanica. 2.We reduced V. pensylvanica populations in large plots managed over multiple years to examine the response of plant–pollinator mutualisms and the fruit production of a functionally important endemic Hawaiian tree species, Metrosideros polymorpha. To integrate knowledge of the invader's behaviour and the plant's mating system, we determined the efficacy of V. pensylvanica as a pollinator of M. polymorpha and quantified the dependence of M. polymorpha on animal pollination (e.g. level of self-compatibility and pollen limitation). 3.The reduction of V. pensylvanica in managed sites, when compared to unmanaged sites, resulted in a significant increase in the visitation rates of effective bee pollinators (e.g. introduced Apis mellifera and native Hylaeus spp.) and in the fruit production of M. polymorpha. 4.Apis mellifera, following the management of V. pensylvanica, appears to be acting as a substitute pollinator for M. polymorpha, replacing extinct or threatened bird and bee species in our study system. 5.Synthesis and applications. Fruit production of the native M. polymorpha was increased after management of the invasive pollinator predator V. pensylvanica; however, the main pollinators were no longer native but introduced. This research thus demonstrates the diverse impacts of introduced species on ecological function and the ambiguous role they play in restoration. We recommend incorporating ecological function and context into invasive species management as this approach may enable conservation

  5. Climate alters response of an endemic island plant to removal of invasive herbivores

    Science.gov (United States)

    Kathryn, Mceachern A.; Thomson, D.M.; Chess, K.A.

    2009-01-01

    Islands experience higher rates of species extinction than mainland ecosystems, with biological invasions among the leading causes; they also serve as important model systems for testing ideas in basic and applied ecology. Invasive removal programs on islands are conservation efforts that can also be viewed as powerful manipulative experiments, but few data are available to evaluate their effects. We collected demographic and herbivore damage data for Castilleja mollis Pennell, an endangered plant endemic to Santa Rosa Island, California, over a 12-year period before, during, and after the implementation of control for introduced cattle, deer, and elk. We used these long-term data to explore mechanisms underlying herbivore effects, assess the results of herbivore reduction at the scales of both individual plants and populations, and determine how temporal variability in herbivory and plant demography influenced responses to herbivore removals. For individual plants, herbivore effects mediated by disturbance were greater than those of grazing. Deer and elk scraping of the ground substantially increased plant mortality and dormancy and reduced flowering and growth. Stem damage from browsing did not affect survivorship but significantly reduced plant growth and flower production. Herbivore control successfully lowered damage rates, which declined steeply between 1997 and 2000 and have remained relatively low. Castilleja mollis abundances rose sharply after 1997, suggesting a positive effect of herbivore control, but then began to decline steadily again after 2003. The recent decline appears to be driven by higher mean growing season temperatures; interestingly, not only reductions in scraping damage but a period of cooler conditions were significant in explaining increases in C. mollis populations between 1997 and 2002. Our results demonstrate strong effects of introduced herbivores on both plant demography and population dynamics and show that climate

  6. Climate alters response of an endemic island plant to removal of invasive herbivores.

    Science.gov (United States)

    McEachern, A Kathryn; Thomson, Diane M; Chess, Katherine A

    2009-09-01

    Islands experience higher rates of species extinction than mainland ecosystems, with biological invasions among the leading causes; they also serve as important model systems for testing ideas in basic and applied ecology. Invasive removal programs on islands are conservation efforts that can also be viewed as powerful manipulative experiments, but few data are available to evaluate their effects. We collected demographic and herbivore damage data for Castilleja mollis Pennell, an endangered plant endemic to Santa Rosa Island, California, over a 12-year period before, during, and after the implementation of control for introduced cattle, deer, and elk. We used these long-term data to explore mechanisms underlying herbivore effects, assess the results of herbivore reduction at the scales of both individual plants and populations, and determine how temporal variability in herbivory and plant demography influenced responses to herbivore removals. For individual plants, herbivore effects mediated by disturbance were greater than those of grazing. Deer and elk scraping of the ground substantially increased plant mortality and dormancy and reduced flowering and growth. Stem damage from browsing did not affect survivorship but significantly reduced plant growth and flower production. Herbivore control successfully lowered damage rates, which declined steeply between 1997 and 2000 and have remained relatively low. Castilleja mollis abundances rose sharply after 1997, suggesting a positive effect of herbivore control, but then began to decline steadily again after 2003. The recent decline appears to be driven by higher mean growing season temperatures; interestingly, not only reductions in scraping damage but a period of cooler conditions were significant in explaining increases in C. mollis populations between 1997 and 2002. Our results demonstrate strong effects of introduced herbivores on both plant demography and population dynamics and show that climate

  7. The potential impact of invasive woody oil plants on protected areas in China under future climate conditions.

    Science.gov (United States)

    Dai, Guanghui; Yang, Jun; Lu, Siran; Huang, Conghong; Jin, Jing; Jiang, Peng; Yan, Pengbo

    2018-01-18

    Biodiesel produced from woody oil plants is considered a green substitute for fossil fuels. However, a potential negative impact of growing woody oil plants on a large scale is the introduction of highly invasive species into susceptible regions. In this study, we examined the potential invasion risk of woody oil plants in China's protected areas under future climate conditions. We simulated the current and future potential distributions of three invasive woody oil plants, Jatropha curcas, Ricinus communis, and Aleurites moluccana, under two climate change scenarios (RCP2.6 and RCP8.5) up to 2050 using species distribution models. Protected areas in China that will become susceptible to these species were then identified using a spatial overlay analysis. Our results showed that by 2050, 26 and 41 protected areas would be threatened by these invasive woody oil plants under scenarios RCP2.6 and RCP8.5, respectively. A total of 10 unique forest ecosystems and 17 rare plant species could be potentially affected. We recommend that the invasive potential of woody oil plants be fully accounted for when developing forest-based biodiesel, especially around protected areas.

  8. The invasive wetland plant Alternanthera philoxeroides shows a higher tolerance to waterlogging than its native Congener Alternanthera sessilis.

    Directory of Open Access Journals (Sweden)

    Yue Chen

    Full Text Available Plant invasion is one of the major threats to natural ecosystems. Phenotypic plasticity is considered to be important for promoting plant invasiveness. High tolerance of stress can also increase survival of invasive plants in adverse habitats. Limited growth and conservation of carbohydrate are considered to increase tolerance of flooding in plants. However, few studies have examined whether invasive species shows a higher phenotypic plasticity in response to waterlogging or a higher tolerance of waterlogging (lower plasticity than native species. We conducted a greenhouse experiment to compare the growth and morphological and physiological responses to waterlogging of the invasive, clonal, wetland species Alternanthera philoxeroides with those of its co-occurring, native, congeneric, clonal species Alternanthera sessilis. Plants of A. philoxeroides and A. sessilis were subjected to three treatments (control, 0 and 60 cm waterlogging. Both A. philoxeroides and A. sessilis survived all treatments. Overall growth was lower in A. philoxeroides than in A. sessilis, but waterlogging negatively affected the growth of A. philoxeroides less strongly than that of A. sessilis. Alternanthera philoxeroides thus showed less sensitivity of growth traits (lower plasticity and higher waterlogging tolerance. Moreover, the photosynthetic capacity of A. philoxeroides was higher than that of A. sessilis during waterlogging. Alternanthera philoxeroides also had higher total non-structural and non-soluble carbohydrate concentrations than A. sessilis at the end of treatments. Our results suggest that higher tolerance to waterlogging and higher photosynthetic capacity may partly explain the invasion success of A. philoxeroides in wetlands.

  9. Invasive plants and enemy release: evolution of trait means and trait correlations in Ulex europaeus.

    Science.gov (United States)

    Hornoy, Benjamin; Tarayre, Michèle; Hervé, Maxime; Gigord, Luc; Atlan, Anne

    2011-01-01

    Several hypotheses that attempt to explain invasive processes are based on the fact that plants have been introduced without their natural enemies. Among them, the EICA (Evolution of Increased Competitive Ability) hypothesis is the most influential. It states that, due to enemy release, exotic plants evolve a shift in resource allocation from defence to reproduction or growth. In the native range of the invasive species Ulex europaeus, traits involved in reproduction and growth have been shown to be highly variable and genetically correlated. Thus, in order to explore the joint evolution of life history traits and susceptibility to seed predation in this species, we investigated changes in both trait means and trait correlations. To do so, we compared plants from native and invaded regions grown in a common garden. According to the expectations of the EICA hypothesis, we observed an increase in seedling height. However, there was little change in other trait means. By contrast, correlations exhibited a clear pattern: the correlations between life history traits and infestation rate by seed predators were always weaker in the invaded range than in the native range. In U. europaeus, the role of enemy release in shaping life history traits thus appeared to imply trait correlations rather than trait means. In the invaded regions studied, the correlations involving infestation rates and key life history traits such as flowering phenology, growth and pod density were reduced, enabling more independent evolution of these key traits and potentially facilitating local adaptation to a wide range of environments. These results led us to hypothesise that a relaxation of genetic correlations may be implied in the expansion of invasive species.

  10. Invasive plants and enemy release: evolution of trait means and trait correlations in Ulex europaeus.

    Directory of Open Access Journals (Sweden)

    Benjamin Hornoy

    Full Text Available Several hypotheses that attempt to explain invasive processes are based on the fact that plants have been introduced without their natural enemies. Among them, the EICA (Evolution of Increased Competitive Ability hypothesis is the most influential. It states that, due to enemy release, exotic plants evolve a shift in resource allocation from defence to reproduction or growth. In the native range of the invasive species Ulex europaeus, traits involved in reproduction and growth have been shown to be highly variable and genetically correlated. Thus, in order to explore the joint evolution of life history traits and susceptibility to seed predation in this species, we investigated changes in both trait means and trait correlations. To do so, we compared plants from native and invaded regions grown in a common garden. According to the expectations of the EICA hypothesis, we observed an increase in seedling height. However, there was little change in other trait means. By contrast, correlations exhibited a clear pattern: the correlations between life history traits and infestation rate by seed predators were always weaker in the invaded range than in the native range. In U. europaeus, the role of enemy release in shaping life history traits thus appeared to imply trait correlations rather than trait means. In the invaded regions studied, the correlations involving infestation rates and key life history traits such as flowering phenology, growth and pod density were reduced, enabling more independent evolution of these key traits and potentially facilitating local adaptation to a wide range of environments. These results led us to hypothesise that a relaxation of genetic correlations may be implied in the expansion of invasive species.

  11. Ecological impacts of non-native species

    Science.gov (United States)

    Wilkinson, John W.

    2012-01-01

    Non-native species are considered one of the greatest threats to freshwater biodiversity worldwide (Drake et al. 1989; Allen and Flecker 1993; Dudgeon et al. 2005). Some of the first hypotheses proposed to explain global patterns of amphibian declines included the effects of non-native species (Barinaga 1990; Blaustein and Wake 1990; Wake and Morowitz 1991). Evidence for the impact of non-native species on amphibians stems (1) from correlative research that relates the distribution or abundance of a species to that of a putative non-native species, and (2) from experimental tests of the effects of a non-native species on survival, growth, development or behaviour of a target species (Kats and Ferrer 2003). Over the past two decades, research on the effects of non-native species on amphibians has mostly focused on introduced aquatic predators, particularly fish. Recent research has shifted to more complex ecological relationships such as influences of sub-lethal stressors (e.g. contaminants) on the effects of non-native species (Linder et al. 2003; Sih et al. 2004), non-native species as vectors of disease (Daszak et al. 2004; Garner et al. 2006), hybridization between non-natives and native congeners (Riley et al. 2003; Storfer et al. 2004), and the alteration of food-webs by non-native species (Nystrom et al. 2001). Other research has examined the interaction of non-native species in terms of facilitation (i.e. one non-native enabling another to become established or spread) or the synergistic effects of multiple non-native species on native amphibians, the so-called invasional meltdown hypothesis (Simerloff and Von Holle 1999). Although there is evidence that some non-native species may interact (Ricciardi 2001), there has yet to be convincing evidence that such interactions have led to an accelerated increase in the number of non-native species and cumulative impacts are still uncertain (Simberloff 2006). Applied research on the control, eradication, and

  12. Responses of soil N-fixing bacteria communities to invasive plant species under different types of simulated acid deposition

    Science.gov (United States)

    Wang, Congyan; Zhou, Jiawei; Jiang, Kun; Liu, Jun; Du, Daolin

    2017-06-01

    Biological invasions have incurred serious threats to native ecosystems in China, and soil N-fixing bacteria communities (SNB) may play a vital role in the successful plant invasion. Meanwhile, anthropogenic acid deposition is increasing in China, which may modify or upgrade the effects that invasive plant species can cause on SNB. We analyzed the structure and diversity of SNB by means of new generation sequencing technology in soils with different simulated acid deposition (SAD), i.e., different SO4 2- to NO3 - ratios, and where the invasive ( Amaranthus retroflexus L.) and the native species ( Amaranthus tricolor L.) grew mixed or isolated for 3 months. A. retroflexus itself did not exert significant effects on the diversity and richness of SNB but did it under certain SO4 2- to NO3 - ratios. Compared to soils where the native species grew isolated, the soils where the invasive A. retroflexus grew isolated showed lower relative abundance of some SNB classes under certain SAD treatments. Some types of SAD can alter soil nutrient content which in turn could affect SNB diversity and abundance. Specifically, greater SO4 2- to NO3 - ratios tended to have more toxic effects on SNB likely due to the higher exchange capacity of hydroxyl groups (OH-) between SO4 2- and NO3 -. As a conclusion, it can be expected a change in the structure of SNB after A. retroflexus invasion under acid deposition rich in sulfuric acid. This change may create a plant soil feedback favoring future A. retroflexus invasions.

  13. Home range use and movement patterns of non-native feral goats in a tropical island montane dry landscape.

    Science.gov (United States)

    Chynoweth, Mark W; Lepczyk, Christopher A; Litton, Creighton M; Hess, Steven C; Kellner, James R; Cordell, Susan

    2015-01-01

    Advances in wildlife telemetry and remote sensing technology facilitate studies of broad-scale movements of ungulates in relation to phenological shifts in vegetation. In tropical island dry landscapes, home range use and movements of non-native feral goats (Capra hircus) are largely unknown, yet this information is important to help guide the conservation and restoration of some of the world's most critically endangered ecosystems. We hypothesized that feral goats would respond to resource pulses in vegetation by traveling to areas of recent green-up. To address this hypothesis, we fitted six male and seven female feral goats with Global Positioning System (GPS) collars equipped with an Argos satellite upload link to examine goat movements in relation to the plant phenology using the Normalized Difference Vegetation Index (NDVI). Movement patterns of 50% of males and 40% of females suggested conditional movement between non-overlapping home ranges throughout the year. A shift in NDVI values corresponded with movement between primary and secondary ranges of goats that exhibited long-distance movement, suggesting that vegetation phenology as captured by NDVI is a good indicator of the habitat and movement patterns of feral goats in tropical island dry landscapes. In the context of conservation and restoration of tropical island landscapes, the results of our study identify how non-native feral goats use resources across a broad landscape to sustain their populations and facilitate invasion of native plant communities.

  14. Home range use and movement patterns of non-native feral goats in a tropical island montane dry landscape

    Science.gov (United States)

    Chynoweth, Mark W.; Lepczyk, Christopher A.; Litton, Creighton M.; Hess, Steve; Kellner, James; Cordell, Susan

    2015-01-01

    Advances in wildlife telemetry and remote sensing technology facilitate studies of broad-scale movements of ungulates in relation to phenological shifts in vegetation. In tropical island dry landscapes, home range use and movements of non-native feral goats (Capra hircus) are largely unknown, yet this information is important to help guide the conservation and restoration of some of the world’s most critically endangered ecosystems. We hypothesized that feral goats would respond to resource pulses in vegetation by traveling to areas of recent green-up. To address this hypothesis, we fitted six male and seven female feral goats with Global Positioning System (GPS) collars equipped with an Argos satellite upload link to examine goat movements in relation to the plant phenology using the Normalized Difference Vegetation Index (NDVI). Movement patterns of 50% of males and 40% of females suggested conditional movement between non-overlapping home ranges throughout the year. A shift in NDVI values corresponded with movement between primary and secondary ranges of goats that exhibited long-distance movement, suggesting that vegetation phenology as captured by NDVI is a good indicator of the habitat and movement patterns of feral goats in tropical island dry landscapes. In the context of conservation and restoration of tropical island landscapes, the results of our study identify how non-native feral goats use resources across a broad landscape to sustain their populations and facilitate invasion of native plant communities.

  15. Kalispel Non-Native Fish Suppression Project 2007 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Wingert, Michele; Andersen, Todd [Kalispel Natural Resource Department

    2008-11-18

    Non-native salmonids are impacting native salmonid populations throughout the Pend Oreille Subbasin. Competition, hybridization, and predation by non-native fish have been identified as primary factors in the decline of some native bull trout (Salvelinus confluentus) and westslope cutthroat trout (Oncorhynchus clarki lewisi) populations. In 2007, the Kalispel Natural Resource Department (KNRD) initiated the Kalispel Nonnative Fish Suppression Project. The goal of this project is to implement actions to suppress or eradicate non-native fish in areas where native populations are declining or have been extirpated. These projects have previously been identified as critical to recovering native bull trout and westslope cutthroat trout (WCT). Lower Graham Creek was invaded by non-native rainbow (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis) after a small dam failed in 1991. By 2003, no genetically pure WCT remained in the lower 700 m of Graham Creek. Further invasion upstream is currently precluded by a relatively short section of steep, cascade-pool stepped channel section that will likely be breached in the near future. In 2008, a fish management structure (barrier) was constructed at the mouth of Graham Creek to preclude further invasion of non-native fish into Graham Creek. The construction of the barrier was preceded by intensive electrofishing in the lower 700 m to remove and relocate all captured fish. Westslope cutthroat trout have recently been extirpated in Cee Cee Ah Creek due to displacement by brook trout. We propose treating Cee Cee Ah Creek with a piscicide to eradicate brook trout. Once eradication is complete, cutthroat trout will be translocated from nearby watersheds. In 2004, the Washington Department of Fish and Wildlife (WDFW) proposed an antimycin treatment within the subbasin; the project encountered significant public opposition and was eventually abandoned. However, over the course of planning this 2004 project, little public

  16. History of nonnative Monk Parakeets in Mexico.

    Science.gov (United States)

    Hobson, Elizabeth A; Smith-Vidaurre, Grace; Salinas-Melgoza, Alejandro

    2017-01-01

    Nonnative Monk Parakeets have been reported in increasing numbers across many cities in Mexico, and were formally classified as an invasive species in Mexico in late 2016. However, there has not been a large-scale attempt to determine how international pet trade and national and international governmental regulations have played a part in colonization, and when the species appeared in different areas. We describe the changes in regulations that led the international pet trade market to shift to Mexico, then used international trade data to determine how many parakeets were commercially imported each year and where those individuals originated. We also quantified the recent increases in Monk Parakeet (Myiopsitta monachus) sightings in Mexico in both the scientific literature and in citizen science reports. We describe the timeline of increased reports to understand the history of nonnative Monk Parakeets in Mexico. As in other areas where the species has colonized, the main mode of transport is through the international pet trade. Over half a m