WorldWideScience

Sample records for invasive plants

  1. 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...

  2. Invasive Plants -- A Horticultural Perspective

    OpenAIRE

    Niemiera, Alexander Xavier, 1951-; Von Holle, Betsy

    2009-01-01

    This publication explains how nonnative invasive plants are harmful and why you should care, how to predict the invasive potential of a plant, and how gardeners and landscape professionals can make informed choices when choosing plants.

  3. Prioritizing invasive plant management strategies

    Science.gov (United States)

    Invasive plants are seriously impacting rangelands by displacing desirable species. Management of these species is expensive and careful allocation of scarce dollars is necessary. Ecologically-based invasive plant management (EBIPM) has the potential to provide an improved decision-making process ...

  4. 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...

  5. Invasive exotic plants suffer less herbivory than non-invasive exotic plants

    OpenAIRE

    Cappuccino, Naomi; Carpenter, David

    2005-01-01

    We surveyed naturally occurring leaf herbivory in nine invasive and nine non-invasive exotic plant species sampled in natural areas in Ontario, New York and Massachusetts, and found that invasive plants experienced, on average, 96% less leaf damage than non-invasive species. Invasive plants were also more taxonomically isolated than non-invasive plants, belonging to families with 75% fewer native North American genera. However, the relationship between taxonomic isolation at the family level ...

  6. 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...

  7. 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...

  8. 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.

  9. Alabama invasive plant council: list of invasive plants by cultural use categories

    Science.gov (United States)

    James H. Miller; Nancy J. Loewenstein; Curtis J. Hansen

    2006-01-01

    Shortly after formation of the Alabama Invasive Plant Council (ALIPC) in 2003, a committee dedicated to assessment and listing of invasive plants was convened – the ALIPC Invasive Plant Listing Committee. Committee members were drawn from the wide diversity of expertise of the Council, which welcomes participation by all land-use and water-use managers, owners,...

  10. 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…

  11. 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...

  12. A subcontinental view of forest plant invasions

    Directory of Open Access Journals (Sweden)

    Christopher M. Oswalt

    2015-01-01

    Full Text Available Over the last few decades, considerable attention has focused on small-scale studies of invasive plants and invaded systems. Unfortunately, small scale studies rarely provide comprehensive insight into the complexities of biological invasions at macroscales. Systematic and repeated monitoring of biological invasions at broad scales are rare. In this report, we highlight a unique invasive plant database from the national Forest Inventory and Analysis (FIA program of the United States Forest Service. We demonstrate the importance and capability of this subcontinental-wide database by showcasing several critical macroscale invasion patterns that have emerged from its initial analysis: (1 large portion of the forests systems (39% in the United States are impacted by invasive plants, (2 forests in the eastern United States harbor more invasive species than the western regions, (3 human land-use legacies at regional to national scales may drive large-scale invasion patterns. This accumulated dataset, which continues to grow in temporal richness with repeated measurements, will allow the understanding of invasion patterns and processes at multi-spatial and temporal scales. Such insights are not possible from smaller-scale studies, illustrating the benefit that can be gained by investing in the development of regional to continental-wide invasion monitoring programs elsewhere.

  13. [Interactions between invasive plants and arbuscular mycorrhizal fungi: a review].

    Science.gov (United States)

    Bai, Yan-fang; Guo, Shao-xia; Li, Min

    2011-09-01

    The invasion of invasive plants changes the biological community structure in their invaded lands, leading to the biodiversity loss. As an important component of soil microorganisms in terrestrial ecosystem, arbuscular mycorrhizal (AM) fungi can affect the growth performance of invasive plants. This kind of specific relations between AM fungi and invasive plants also implies that AM fungi can affect plant invasion. On the other hand, the invasion of invasive plants can affect the community structure and function of AM fungi. This paper summarized the species and harms of invasive plants in China, and discussed the relationships between AM fungi and invasive plants invasion, including the roles of AM fungi in the processes of invasive plants invasion, the effects of the invasion on AM fungi, and the interactive mechanisms between the invasion and AM fungi.

  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. 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

  16. 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

  17. 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...

  18. How can phytochemists benefit from invasive plants?

    Science.gov (United States)

    Fan, Peihong; Marston, Andrew

    2009-10-01

    The phenomenon of invasive alien species has become one of the greatest threats to the biological diversity of the planet, placing major constraints on development. In order to provide the tools needed to address this pervasive issue, the current knowledge on invasive species must be further developed with a cross-sectoral and multi-disciplinary approach. Recent theories of invasion propose that exotic plants probably produce secondary metabolites which can be allelopathic, anti-herbivore, anti-microbial and which are either unique or underrepresented in the plants' new range. This review attempts to attract the attention of phytochemists to study either the mechanisms of plant invasion or to use this widespread plant resource for humans.

  19. Exotic invasive plants in southeastern forests

    Science.gov (United States)

    James H. Miller

    1998-01-01

    Invasive exotic plants usurp forest productivity, hinder forest-use activities, and limit diversity on millions of acres of forest land in the Southeast Infestations of these plants and their range are constantly expanding, This paper examines the various aspects of the problem. Outlined are the biology, origin, range, uses, and herbicide control for 14 of the most...

  20. Uprooting and burial of invasive alien plants

    DEFF Research Database (Denmark)

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

    2011-01-01

    Invasive alien plants are a problem for conservation management, and control of these species can be combined with habitat restoration. Subsoil burial of uprooted plants is a new method of mechanical control, which might be suitable in disturbed habitats. The method was tested in Rosa rugosa...

  1. The social dimensions of invasive plants.

    Science.gov (United States)

    Head, Lesley

    2017-06-06

    Invasive plants pose a major environmental management issue. Research into the social dimensions of this issue has flourished over the past decade, as part of the critical examination of relations between human and nonhuman worlds. The social sciences and humanities have made substantial contributions to conceptualizing invasiveness and nativeness; understanding the perceptions, attitudes and values of diverse stakeholders; and analysing the politics and practices of invasive plant management. Cultural analysis allows areas of conflict and commonality to be identified. Social complexity must be added to ecological complexity to understand the causal relationships underlying invasions; and linear understandings of science-policy relationships are too simplistic. Productive connections have been established between recent social and natural science approaches in the context of rapid environmental change and unpredictable futures. Nonetheless, the prevalence of human exceptionalism in the ecological sciences constitutes a major point of divergence between social and natural science perspectives.

  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. Economic savings from invasive plant prevention

    Science.gov (United States)

    Prevention programs are often assumed to be the most cost-effective method for managing invasive plants. However, there is very little information about economic and biological factors that determine the forage benefits resulting from prevention programs. We developed a simple economic model to asse...

  6. 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

  7. 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...

  8. Curvilinear effects of invasive plants on plant diversity: plant community invaded by Sphagneticola trilobata.

    Science.gov (United States)

    Qi, Shan-Shan; Dai, Zhi-Cong; Zhai, De-Li; Chen, Si-Chong; Si, Chun-Can; Huang, Ping; Wang, Rui-Ping; Zhong, Qiong-Xin; Du, Dao-Lin

    2014-01-01

    The effects of invasive plants on the species diversity of plant communities are controversial, showing either a positive or negative linear relationship. Based on community data collected from forty 5 m×5 m plots invaded by Sphagneticola trilobata in eight cities across Hainan Island, China, we found S. trilobata decreased plant community diversity once its cover was beyond 10%. We demonstrated that the effects of invasive/native plants on the plant diversity of communities invaded by S. trilobata were curvilinear. These effects, which showed peaks under different degrees of vegetation cover, appeared not only for S. trilobata and all invasive plants, but also for all native plants. Invasive plants primarily had negative effects on plant diversity when they became abundant at a much lower cover level (less than 35%), compared with the native plants (over 60%). Thus, it is necessary to distinguish a range for assessing the effects of plants, especially invasive plants. Our results also confirmed that the invasion intensity of invasive alien plants increased with the intensity of local economic development. We highlight and further discuss the critical importance of curvilinear effects of biological invasion to provide ideas regarding the conservation of local biodiversity and the management of invasive plants.

  9. 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.

  10. Invasive plant species and the Joint Fire Science Program.

    Science.gov (United States)

    Heather E. Erickson; Rachel White

    2007-01-01

    Invasive nonnative plants may be responsible for serious, long-term ecological impacts, including altering fire behavior and fire regimes. Therefore, knowing how to successfully manage invasive plants and their impacts on natural resources is crucial. We present a summary of research on invasive plants and fire that has been generated through the Joint Fire Science...

  11. 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

  12. Climate warming, plant invasions and plant-enemy interactions

    NARCIS (Netherlands)

    Engelkes, T.

    2010-01-01

    The climate is changing and temperatures are predicted to further increase in the future. Species respond to these changes by either adapting to the local warmer conditions and/or range shifting to higher latitudes. Some of these successful range shifting plants can become invasive in their new

  13. Pollination of a native plant changes with distance and density of invasive plants in a simulated biological invasion.

    Science.gov (United States)

    Bruckman, Daniela; Campbell, Diane R

    2016-08-01

    Effects of an exotic plant on pollination may change as the invasive increases in density. Quantity of pollinator visits to a native may increase, decrease, or change nonlinearly, while visit quality is likely to decrease with greater interspecific pollen movement. How visit quantity and quality contribute to the effect on reproductive success at each invasion stage has not been measured. We simulated four stages of invasion by Brassica nigra by manipulating the neighborhood of potted plants of the native Phacelia parryi in a field experiment. Stages were far from the invasion, near the invasion, intermixed with the invasive at low density, and intermixed at high density. We measured pollinator visitation, conspecific and invasive pollen deposition, and seed set for P. parryi at each stage. Native individuals near invasive plants and within areas of low invasive density showed greatest seed production, as expected from concurrent changes in conspecific and invasive pollen deposition. Those plants experienced facilitation of visits and received more conspecific pollen relative to plants farther from invasives. Native individuals within high invasive density also received frequent visits by many pollinators (although not honeybees), but the larger receipt of invasive pollen predicted interference with pollen tubes that matched patterns in seed set. Pollinator visitation was highest when exotic plants were nearby. Detrimental effects of heterospecific pollen deposition were highest at high exotic density. Our study quantified how reproduction benefits from near proximity to a showy invasive, but is still vulnerable when the invasive reaches high density. © 2016 Botanical Society of America.

  14. 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...

  15. Geospatial assessment of invasive plants on reclaimed mines in Alabama

    Science.gov (United States)

    D. Lemke; C.J. Schweitzer; W. Tadesse; Y. Wang; J.A. Brown

    2013-01-01

    Throughout the world, the invasion of nonnative plants is an increasing threat to native biodiversity and ecosystem sustainability. Invasion is especially prevalent in areas affected by land transformation and disturbance. Surface mines are a major land transformation, and thus may promote the establishment and persistence of invasive plant communities. Using the Shale...

  16. Impact of invasive plants on food webs and pathways

    OpenAIRE

    Sikai Wang; Qiang Sheng; Tianjiang Chu; Bo Li; Jiakuan Chen; Jihua Wu

    2013-01-01

    In natural ecosystems, energy mainly flows along food chains in food webs. Numerous studies have shown that plant invasions influence ecosystem functions through altering food webs. In recent decades, more attention has been paid to the effects of alien plants on local food webs. In this review, we analyze the influence of exotic plants on food webs and pathways, and explore the impacts of local food web characteristics on community invasibility. Invasive plants alter food webs mainly by chan...

  17. Ensemble habitat mapping of invasive plant species

    Science.gov (United States)

    Stohlgren, T.J.; Ma, P.; Kumar, S.; Rocca, M.; Morisette, J.T.; Jarnevich, C.S.; Benson, N.

    2010-01-01

    Ensemble species distribution models combine the strengths of several species environmental matching models, while minimizing the weakness of any one model. Ensemble models may be particularly useful in risk analysis of recently arrived, harmful invasive species because species may not yet have spread to all suitable habitats, leaving species-environment relationships difficult to determine. We tested five individual models (logistic regression, boosted regression trees, random forest, multivariate adaptive regression splines (MARS), and maximum entropy model or Maxent) and ensemble modeling for selected nonnative plant species in Yellowstone and Grand Teton National Parks, Wyoming; Sequoia and Kings Canyon National Parks, California, and areas of interior Alaska. The models are based on field data provided by the park staffs, combined with topographic, climatic, and vegetation predictors derived from satellite data. For the four invasive plant species tested, ensemble models were the only models that ranked in the top three models for both field validation and test data. Ensemble models may be more robust than individual species-environment matching models for risk analysis. ?? 2010 Society for Risk Analysis.

  18. List of invasive plants by cultural use categories

    Science.gov (United States)

    James H. Miller; Nancy J. Loewenstein; Curtis J. Hansen

    2006-01-01

    Shortly after formation of the Alabama Invasive Plant Council (ALIPC) in 2003, a committee dedicated to assessment and listing of massive plants was convened - the ALIPC Invasive Plant Listing Committee. Committee members were drawn from the wide diversity of expertise of the Council, which welcomes participation by all land-use and water-use managers. owners, stewards...

  19. 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...

  20. 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.

  1. Paradigm of plant invasion: multifaceted review on sustainable management.

    Science.gov (United States)

    Rai, Prabhat Kumar

    2015-12-01

    A cascade of reviews and growing body of literature exists on forest invasion ecology, its mechanism or causes; however, no review addressed the sustainable management of invasive plants of forest in totality. Henceforth, the present paper aims to provide a critical review on the management of invasive species particularly in the context of forest plants. Plant invasion in forest is now increasingly being recognized as a global problem, and various continents are adversely affected, although to a differential scale. Quest for the ecological mechanism lying behind the success of invasive species over native species of forest has drawn the attention of researches worldwide particularly in the context of diversity-stability relationship. Transport, colonization, establishment, and landscape spread may be different steps in success of invasive plants in forest, and each and every step is checked through several ecological attributes. Further, several ecological attribute and hypothesis (enemy release, novel weapon, empty niche, evolution of increased competitive ability, etc.) were proposed pertaining to success of invasive plant species in forest ecosystems. However, a single theory will not be able to account for invasion success among all environments as it may vary spatially and temporally. Therefore, in order to formulate a sustainable management plan for invasive plants of forest, it is necessary to develop a synoptic view of the dynamic processes involved in the invasion process. Moreover, invasive species of forest can act synergistically with other elements of global change, including land-use change, climate change, increased concentrations of atmospheric carbon dioxide, and nitrogen deposition. Henceforth, a unified framework for biological invasions that reconciles and integrates the key features of the most commonly used invasion frameworks into a single conceptual model that can be applied to all human-mediated invasions.

  2. 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.

  3. 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...

  4. 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...

  5. 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 ...

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

    African Journals Online (AJOL)

    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 ...

  7. 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...

  8. Invasive plant monitoring for northern U.S. forests

    Science.gov (United States)

    William H. McWilliams; Randall S. Morin; Katherine Johnson; W. Keith Moser; James A. Westfall

    2012-01-01

    Invasive plants are monitored through canopy cover estimates for a list of species developed by FIA for the northern region of the U.S. that is integrated with a national list. Nearly all of the invasive plants on the NRS-FIA list are exotic species, but a few native species are listed. Highly invasive native species such as rhizomatous fern are absent, making the list...

  9. 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.

  10. What makes the plant invasion possible? Paradigm of invasion mechanisms, theories and attributes

    Directory of Open Access Journals (Sweden)

    Prabhat Kumar Rai

    2015-06-01

    Full Text Available Plant invasion is the second most severe threat to biodiversity after habitat fragmentation. Invasive species are alien species whose introduction and spread threatens ecosystems, habitats or species with socio-cultural, economic and/or environmental harm, and harm to human health. Present review precisely describes the global problems of invasion in different ecosystems, continents and its multifaceted impacts. Plant invasion is now increasingly being recognized as global problem and various continents are adversely affected, although to a differential scale. Quest for the ecological mechanism lying behind the success of invasive species over native species has drawn the attention of researches worldwide particularly in context of diversity-stability relationship. Transport, colonization, establishment and landscape spread may be different steps in success of invasive plants and each and every step is checked through several ecological attributes. Further, several ecological attribute and hypothesis (enemy release, novel weapon, empty niche, evolution of increased competitive ability etc. were proposed pertaining to success of invasive plant species. However, single theory will not be able to account for invasion success among all environments as it may vary spatially and temporally. Therefore, in order to formulate a sustainable management plan for invasive plants, it is necessary to develop a synoptic view of the dynamic processes involved in the invasion process. Moreover, invasive species can act synergistically with other elements of global change, including land-use change, climate change, increased concentrations of atmospheric carbon dioxide and nitrogen deposition. Henceforth, a unified framework for biological invasions that reconciles and integrates the key features of the most commonly used invasion frame-works into a single conceptual model that can be applied to all human-mediated invasions.

  11. 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.

  12. Plant Invasions in China – Challenges and Chances

    Science.gov (United States)

    Axmacher, Jan C.; Sang, Weiguo

    2013-01-01

    Invasive species cause serious environmental and economic harm and threaten global biodiversity. We set out to investigate how quickly invasive plant species are currently spreading in China and how their resulting distribution patterns are linked to socio-economic and environmental conditions. A comparison of the invasive plant species density (log species/log area) reported in 2008 with current data shows that invasive species were originally highly concentrated in the wealthy, southeastern coastal provinces of China, but they are currently rapidly spreading inland. Linear regression models based on the species density and turnover of invasive plants as dependent parameters and principal components representing key socio-economic and environmental parameters as predictors indicate strong positive links between invasive plant density and the overall phytodiversity and associated climatic parameters. Principal components representing socio-economic factors and endemic plant density also show significant positive links with invasive plant density. Urgent control and eradication measures are needed in China's coastal provinces to counteract the rapid inland spread of invasive plants. Strict controls of imports through seaports need to be accompanied by similarly strict controls of the developing horticultural trade and underpinned by awareness campaigns for China's increasingly affluent population to limit the arrival of new invaders. Furthermore, China needs to fully utilize its substantial native phytodiversity, rather than relying on exotics, in current large-scale afforestation projects and in the creation of urban green spaces. PMID:23691164

  13. 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.

  14. 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)-but no...... plant provenance.The ISME Journal advance online publication, 14 March 2013; doi:10.1038/ismej.2013.41....

  15. 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

  16. 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.

  17. Invasive plants have broader physiological niches.

    Science.gov (United States)

    Higgins, Steven I; Richardson, David M

    2014-07-22

    Invasive species cost the global economy billions of dollars each year, but ecologists have struggled to predict the risk of an introduced species naturalizing and invading. Although carefully designed experiments are needed to fully elucidate what makes some species invasive, much can be learned from unintentional experiments involving the introduction of species beyond their native ranges. Here, we assess invasion risk by linking a physiologically based species distribution model with data on the invasive success of 749 Australian acacia and eucalypt tree species that have, over more than a century, been introduced around the world. The model correctly predicts 92% of occurrences observed outside of Australia from an independent dataset. We found that invasiveness is positively associated with the projection of physiological niche volume in geographic space, thereby illustrating that species tolerant of a broader range of environmental conditions are more likely to be invasive. Species achieve this broader tolerance in different ways, meaning that the traits that define invasive success are context-specific. Hence, our study reconciles studies that have failed to identify the traits that define invasive success with the urgent and pragmatic need to predict invasive success.

  18. 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.

  19. The impact of invasive fish and invasive riparian plants on the ...

    African Journals Online (AJOL)

    Invasive fish and plants are widespread in the rivers and riparian zones of the Cape Floristic Region of South Africa and represent potential threats to the highly endemic freshwater fauna. We investigated the impact of invasive smallmouth bass (Micropterus dolomieu) and black wattle (Acacia mearnsii) on assemblages of ...

  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. Fire management and woody invasive plants in oak ecosystems

    Science.gov (United States)

    Joanne. Rebbeck

    2012-01-01

    The use of prescribed fire to sustain oak forests has increased rapidly in the last decade as the threat of poor regeneration and increased dominance of shade tolerant or fire sensitive tree species grows. While prescribed fire can favor oak regeneration, it may also increase the invasion and expansion of nonnative invasive plant species (NNIS). Little is known about...

  2. The assessment of invasive alien plant species removal programs ...

    African Journals Online (AJOL)

    Yusuf Adam

    Abstract. The occupation of natural environments by invasive alien plant species (IAPs) are a growing threat to ecosystems. This has resulted in the creation of government-based initiatives to mitigate invasion, however, there has been little progress towards assessing these initiatives. Remote sensing is a commonly used ...

  3. The assessment of invasive alien plant species removal programs ...

    African Journals Online (AJOL)

    The occupation of natural environments by invasive alien plant species (IAPs) are a growing threat to ecosystems. This has resulted in the creation of government-based initiatives to mitigate invasion, however, there has been little progress towards assessing these initiatives. Remote sensing is a commonly used tool in the ...

  4. 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.

  5. 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

  6. Interacting impacts of invasive plants and invasive toads on native lizards.

    Science.gov (United States)

    Price-Rees, Samantha J; Brown, Gregory P; Shine, Richard

    2012-03-01

    The ecological impacts of an invasive species may be reduced by prior invasions if selective pressures imposed by earlier events preadapt the native biota to deal with the newer arrival. In northwestern Australia, invasion of the cane toad (Rhinella marina) kills many native predators if they ingest the highly toxic toads. Remarkably, the toads' defensive toxins (bufadienolides) are chemically similar to those of another invasive species: an ornamental plant from Madagascar, Bryophyllum spp. (Crassulaceae, mother-of-millions). Omnivorous lizards (bluetongue skinks, Tiliqua scincoides) are imperiled by the invasion of toads in northwestern Australia, but conspecifics from other areas of the continent (those where exotic plants were introduced and including areas where toads have yet to invade) are less affected because they exhibit higher physiological tolerance of toad toxins (and also of plant toxins). The willingness of captive bluetongues to consume both toads and these plants and the high correlation in the lizards' sensitivity to toad toxins versus plant toxins suggest that exotic plants may have imposed strong selection on the lizards' physiological tolerance of bufadienolides. As a result, populations of lizards from areas previously exposed to these alien plants may be preadapted to deal with the toxins of the more recent anuran invader.

  7. 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.

  8. Chemical Defenses (Glucosinolates) of Native and Invasive Populations of the Range Expanding Invasive Plant Rorippa austriaca

    NARCIS (Netherlands)

    Huberty, M.; Tielborger, K.; Harvey, J.A.; Muller, C.; Macel, M.

    2014-01-01

    Due to global warming, species are expanding their range to higher latitudes. Some range expanding plants have become invasive in their new range. The Evolution of Increased Competitive Ability (EICA) hypothesis and the Shifting Defense Hypothesis (SDH) predict altered selection on plant defenses in

  9. 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

  10. Root carbon flow from an invasive plant to belowground foodwebs

    Science.gov (United States)

    Mark A. Bradford; Michael S. Strickland; Jayna L. DeVore; John C. Maerz

    2012-01-01

    Aims Soil foodwebs are based on plant production. This production enters belowground foodwebs via numerous pathways, with root pathways likely dominating supply. Indeed, root exudation may fuel 30–50 % of belowground activity with photosynthate fixed only hours earlier. Yet we have limited knowledge of root fluxes of recent-photosynthate from invasive plants to...

  11. 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

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. Effects of invasive woody plants on avian nest site selection and nesting success in shrublands

    Science.gov (United States)

    S. Schlossberg; D.I. King

    2010-01-01

    Exotic, invasive plants are a growing conservation problem. Birds frequently use invasive plants as nest substrates, but effects of invasives on avian nesting success have been equivocal in past studies. In 2004 and 2005, we assessed effects of invasive woody plants on avian nest-site selection and nesting success in western Massachusetts shrublands. At the nest scale...

  17. 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...

  18. 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...

  19. Control techniques for invasive alien plants

    Directory of Open Access Journals (Sweden)

    Michele de Sá Dechoum

    2013-03-01

    Full Text Available Invasive alien species are recognized as a major threat to the conservation of biodiversity. These species should be managed based on local and regional environmental conditions. Control techniques were tested for ten invasive species in Santa Catarina State: the trees Casuarina equisetifolia, Hovenia dulcis, Psidium guajava, Syzygium cumini, and Terminalia catappa, and shrubs and herbs Rubus fruticosus, Furcraea foetida, Hedychium coronarium, Impatiens walleriana, and Tradescantia zebrina. Treatments applied for trees were cut stump, frill and girdling or ring-barking followed by herbicide application, while the other species were treated with foliar spray, application of herbicide on the root system, cut stump and herbicide injection. The active ingredients tested were Triclopyr, Glyphosate, and the combination of Triclopyr + Fluroxipyr in concentrations from 2 to 6%, according to the species. The cut stump method was efficient for all of the woody species, while ring-barking and frilling followed by herbicide application and basal bark application resulted in different levels of efficiency for the species tested. The most efficient method for herbs and shrubs was foliar spray, and the least efficient methods were cut stump and herbicide injection.

  20. Short lag times for invasive tropical plants: evidence from experimental plantings in Hawai'i.

    Science.gov (United States)

    Daehler, Curtis C

    2009-01-01

    The lag time of an invasion is the delay between arrival of an introduced species and its successful spread in a new area. To date, most estimates of lag times for plants have been indirect or anecdotal, and these estimates suggest that plant invasions are often characterized by lag times of 50 years or more. No general estimates are available of lag times for tropical plant invasions. Historical plantings and documentation were used to directly estimate lag times for tropical plant invasions in Hawai'i. Historical planting records for the Lyon Arboretum dating back to 1920 were examined to identify plants that have since become invasive pests in the Hawaiian Islands. Annual reports describing escape from plantings were then used to determine the lag times between initial plantings and earliest recorded spread of the successful invaders. Among 23 species that eventually became invasive pests, the average lag time between introduction and first evidence of spread was 14 years for woody plants and 5 years for herbaceous plants. These direct estimates of lag times are as much as an order of magnitude shorter than previous, indirect estimates, which were mainly based on temperate plants. Tropical invaders may have much shorter lag times than temperate species. A lack of direct and deliberate observations may have also inflated many previous lag time estimates. Although there have been documented cases of long lag times due to delayed arrival of a mutualist or environmental changes over time, this study suggests that most successful invasions are likely to begin shortly after arrival of the plant in a suitable habitat, at least in tropical environments. Short lag times suggest that controlled field trials may be a practical element of risk assessment for plant introductions.

  1. Applications of Remote Sensing to Alien Invasive Plant Studies

    Directory of Open Access Journals (Sweden)

    Gregory P. Asner

    2009-06-01

    Full Text Available Biological invasions can affect ecosystems across a wide spectrum of bioclimatic conditions. Therefore, it is often important to systematically monitor the spread of species over a broad region. Remote sensing has been an important tool for large-scale ecological studies in the past three decades, but it was not commonly used to study alien invasive plants until the mid 1990s. We synthesize previous research efforts on remote sensing of invasive plants from spatial, temporal and spectral perspectives. We also highlight a recently developed state-of-the-art image fusion technique that integrates passive and active energies concurrently collected by an imaging spectrometer and a scanning-waveform light detection and ranging (LiDAR system, respectively. This approach provides a means to detect the structure and functional properties of invasive plants of different canopy levels. Finally, we summarize regional studies of biological invasions using remote sensing, discuss the limitations of remote sensing approaches, and highlight current research needs and future directions.

  2. Ecophysiology of invasive plants: osmotic adjustment and antioxidants.

    Science.gov (United States)

    Pintó-Marijuan, Marta; Munné-Bosch, Sergi

    2013-12-01

    Current research into plant invasiveness often attempts to predict the effect of invasions under future climate change, but most studies only focus on ecological aspects. Understanding ecophysiological responses by characterizing physiological markers such as osmotic adjustment or antioxidant protection indicators will help us to project future invasiveness patterns. In this opinion article, we highlight how the information from physiological measurements can be incorporated into effective management strategies. Furthermore, we propose how combining research strategies of physiologists and ecologists could speed up our understanding of the advantageous mechanisms adopted by invasive species. We suggest that a combined approach would also be of considerable benefit for the development of effective governmental biodiversity conservation policies. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Historic land use influences contemporary establishment of invasive plant species.

    Science.gov (United States)

    Mattingly, W Brett; Orrock, John L

    2013-08-01

    The legacy of agricultural land use can have widespread and persistent effects on contemporary landscapes. Although agriculture can lead to persistent changes in soil characteristics and plant communities, it remains unclear whether historic agricultural land use can alter the likelihood of contemporary biological invasions. To understand how agricultural land-use history might interact with well-known drivers of invasion, we conducted factorial manipulations of soil disturbance and resource additions within non-agricultural remnant sites and post-agricultural sites invaded by two non-native Lespedeza species. Our results reveal that variation in invader success can depend on the interplay of historic land use and contemporary processes: for both Lespedeza species, establishment was greater in remnant sites, but soil disturbance enhanced establishment irrespective of land-use history, demonstrating that contemporary processes can help to overcome legacy constraints on invader success. In contrast, additions of resources known to facilitate seedling recruitment (N and water) reduced invader establishment in post-agricultural but not in remnant sites, providing evidence that interactions between historic and contemporary processes can also limit invader success. Our findings thus illustrate that a consideration of historic land use may help to clarify the often contingent responses of invasive plants to known determinants of invasibility. Moreover, in finding significantly greater soil compaction at post-agricultural sites, our study provides a putative mechanism for historic land-use effects on contemporary invasive plant establishment. Our work suggests that an understanding of invasion dynamics requires knowledge of anthropogenic events that often occur decades before the introduction of invasive propagules.

  4. 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...

  5. Riparian vegetation: degradation, alien plant invasions, and restoration prospects

    Czech Academy of Sciences Publication Activity Database

    Richardson, D. M.; Holmes, P. M.; Esler, K. J.; Galatowitsch, S. M.; Stromberg, J. C.; Kirkman, S. P.; Pyšek, Petr; Hobbs, R. J.

    2007-01-01

    Roč. 13, č. 1 (2007), s. 126-139 ISSN 1366-9516 Institutional research plan: CEZ:AV0Z60050516 Keywords : riparian habitats * plant invasions * biogeography Subject RIV: EF - Botanics Impact factor: 2.965, year: 2007

  6. Response of native insect communities to invasive plants

    NARCIS (Netherlands)

    Bezemer, T.M.; Harvey, J.A.; Cronin, J.T.

    2014-01-01

    Invasive plants can disrupt a range of trophic interactions in native communities. As 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.

  7. Invasive plant ecology and management: Linking processes to practice

    Science.gov (United States)

    This book brings together 10 chapters from renowned researchers that study how ecosystems operate and how to adopt the principles of ecology to manage invasive plants. This book taps this expertise by seeking to bridge the inherent disconnect between processes operating within ecosystems and the pr...

  8. 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,...

  9. Wildfire and invasive plants in American deserts: a special feature

    Science.gov (United States)

    The Society for Range Management (SRM) and 26 partners hosted a special conference in Reno, Nevada in December of 2008 in response to the need to provide information for the management of native rangelands in the face of challenges posed by the interactions of invasive plants and wildfire. SRM hoste...

  10. Response of Native Insect Communities to Invasive Plants

    NARCIS (Netherlands)

    Bezemer, T.M.; Harvey, J.A.; Cronin, J.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.

  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. Mechanisms of plant invasions of North American and European grasslands

    Czech Academy of Sciences Publication Activity Database

    Seastedt, T. R.; Pyšek, Petr

    2011-01-01

    Roč. 42, - (2011), s. 133-153 ISSN 1543-592X R&D Projects: GA MŠk LC06073; GA ČR(CZ) GAP505/11/1112 Institutional research plan: CEZ:AV0Z60050516 Keywords : plant invasions * grasslands * North America and Europe Subject RIV: EF - Botanics Impact factor: 14.373, year: 2011

  13. 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...

  14. The identification and remote detection of alien invasive plants in ...

    African Journals Online (AJOL)

    Kabir Peerbhay

    The identification and remote detection of alien invasive plants in commercial forests: An Overview. Kabir Peerbhay* Onisimo Mutanga and Riyad Ismail. University of KwaZulu-Natal, School of Agricultural, Earth and Environmental Sciences, Discipline of Geography,. P/Bag X01, Scottsville 3209, Pietermaritzburg, South ...

  15. 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.

  16. 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...

  17. 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...

  18. Environmental Assessment: Invasive Pest Plant Management

    Science.gov (United States)

    2005-01-01

    biotypes such as kochia, prickly lettuce , and Russian thistle are suspected or known to be present use a tank- mix partner with ESCORT® to help control...planted seedlings after the soil has settled around the root systems but before the seedlings have broken dormancy (bud break). 4 Release --Herbaceous...stresses may injure or kill the seedlings . Applications of ESCORT® made for release should only be made after adequate rainfall has closed the

  19. 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.

  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. Application Natura 2000 Data For The Invasive Plants Spread Prediction*

    Directory of Open Access Journals (Sweden)

    Pěknicová J.

    2015-12-01

    Full Text Available The distribution of invasive plants depends on several environmental factors, e.g. on the distance from the vector of spreading, invaded community composition, land-use, etc. The species distribution models, a research tool for invasive plants spread prediction, involve the combination of environmental factors, occurrence data, and statistical approach. For the construction of the presented distribution model, the occurrence data on invasive plants (Solidago sp., Fallopia sp., Robinia pseudoaccacia, and Heracleum mantegazzianum and Natura 2000 habitat types from the Protected Landscape Area Kokořínsko have been intersected in ArcGIS and statistically analyzed. The data analysis was focused on (1 verification of the accuracy of the Natura 2000 habitat map layer, and the accordance with the habitats occupied by invasive species and (2 identification of a suitable scale of intersection between the habitat and species distribution. Data suitability was evaluated for the construction of the model on local scale. Based on the data, the invaded habitat types were described and the optimal scale grid was evaluated. The results show the suitability of Natura 2000 habitat types for modelling, however more input data (e.g. on soil types, elevation are needed.

  2. Combustion characteristics of north-eastern USA vegetation tested in the cone calorimeter: invasive versus non-invasive plants

    Science.gov (United States)

    Alison C. Dibble; Robert H. White; Patricia K. Lebow

    2007-01-01

    In the north-eastern United States, invasive plants alter forest fuels, but their combustion characteristics are largely unknown. We assessed unground samples of foliage and twigs in the cone calorimeter for 21 non-invasive, native species, paired with 21 invasive species (18 non-native). Variables included sustained ignition, peak heat release rate, total heat release...

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

    Science.gov (United States)

    Menzel, Andreas; Hempel, Stefan; Klotz, Stefan; Moora, Mari; Pyšek, Petr; Rillig, Matthias C; Zobel, Martin; Kühn, Ingolf

    2017-01-01

    It is still debated whether alien plants benefit from being mycorrhizal, or if engaging in the symbiosis constrains their establishment and spread in new regions. We analyzed the association between mycorrhizal status of alien plant species in Germany and their invasion success. We compared whether the representation of species with different mycorrhizal status (obligate, facultative, or non-mycorrhizal) differed at several stages of the invasion process. We used generalized linear models to explain the occupied geographical range of alien plants, incorporating interactions of mycorrhizal status with plant traits related to morphology, reproduction, and life-history. Non-naturalized aliens did not differ from naturalized aliens in the relative frequency of different mycorrhizal status categories. Mycorrhizal status significantly explained the occupied range of alien plants; with facultative mycorrhizal species inhabiting a larger range than non-mycorrhizal aliens and obligate mycorrhizal plant species taking an intermediate position. Aliens with storage organs, shoot metamorphoses, or specialized structures promoting vegetative dispersal occupied a larger range when being facultative mycorrhizal. We conclude that being mycorrhizal is important for the persistence of aliens in Germany and constitutes an advantage compared to being non-mycorrhizal. Being facultative mycorrhizal seems to be especially advantageous for successful spread, as the flexibility of this mycorrhizal status may enable plants to use a broader set of ecological strategies. © 2016 by the Ecological Society of America.

  4. DISTRIBUTION OF SELECTED INVASIVE PLANTS IN RIPARIAN ECOSYSTEMS OF THE WESTERN UNITED STATES

    Science.gov (United States)

    Riparian ecosystems typically exhibit high levels of plant species richness, physical disturbance, and interconnectedness; characteristics that may favor establishment and spread of invasive plant species. To assess the magnitude of this invasion, we organized an extensive surve...

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

    Science.gov (United States)

    Lind, Eric M; Parker, John D

    2010-05-03

    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.

  6. 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.

  7. 78 FR 64909 - Southwestern Region: Invasive Plant Control Project, Carson and Santa Fe National Forests, New...

    Science.gov (United States)

    2013-10-30

    ... DEPARTMENT OF AGRICULTURE Forest Service Southwestern Region: Invasive Plant Control Project... Register (65 FR 78464) to prepare an environmental impact statement (EIS) for controlling invasive plants... update certain elements of the analysis and correct deficiencies identified in the 2005 Invasive Plant...

  8. 75 FR 60405 - Lincoln National Forest, New Mexico, Integrated Non-Native Invasive Plant Project

    Science.gov (United States)

    2010-09-30

    ...-Native Invasive Plant Project AGENCY: Forest Service, USDA. ACTION: Notice of Intent to prepare an... Forest-wide management strategy to control spread of non- native invasive plants (NNIP) within the LNF..., controlled grazing, manual/mechanical methods, and adaptive management. Invasive plants designated by the...

  9. 76 FR 36896 - Salmon-Challis National Forest, ID; Forestwide Invasive Plant Treatment Environmental Impact...

    Science.gov (United States)

    2011-06-23

    ... prepare an environmental impact statement. SUMMARY: Invasive plants have been identified as a major threat... Forest. Invasive plants create many adverse environmental effects, including, but not limited to... lands are also threatened by ``potential invaders,'' invasive plants that have not been found on the...

  10. 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

  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. 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

  13. 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

  14. 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

  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. 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.

  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. 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.

  19. Indirect interactions between invasive and native plants via pollinators

    Science.gov (United States)

    Kaiser-Bunbury, Christopher N.; Müller, Christine B.

    2009-03-01

    In generalised pollination systems, the presence of alien plant species may change the foraging behaviour of pollinators on native plant species, which could result in reduced reproductive success of native plant species. We tested this idea of indirect interactions on a small spatial and temporal scale in a field study in Mauritius, where the invasive strawberry guava, Psidium cattleianum, provides additional floral resources for insect pollinators. We predicted that the presence of flowering guava would indirectly and negatively affect the reproductive success of the endemic plant Bertiera zaluzania, which has similar flowers, by diverting shared pollinators. We removed P. cattleianum flowers within a 5-m radius from around half the B. zaluzania target plants (treatment) and left P. cattleianum flowers intact around the other half (control). By far, the most abundant and shared pollinator was the introduced honey bee, Apis mellifera, but its visitation rates to treatment and control plants were similar. Likewise, fruit and seed set and fruit size and weight of B. zaluzania were not influenced by the presence of P. cattleianum flowers. Although other studies have shown small-scale effects of alien plant species on neighbouring natives, we found no evidence for such negative indirect interactions in our system. The dominance of introduced, established A. mellifera indicates their replacement of native insect flower visitors and their function as pollinators of native plant species. However, the pollination effectiveness of A. mellifera in comparison to native pollinators is unknown.

  20. Impacts of invasive plants on resident animals across ecosystems, taxa, and feeding types: a global assessment.

    Science.gov (United States)

    Schirmel, Jens; Bundschuh, Mirco; Entling, Martin H; Kowarik, Ingo; Buchholz, Sascha

    2016-02-01

    As drivers of global change, biological invasions have fundamental ecological consequences. However, it remains unclear how invasive plant effects on resident animals vary across ecosystems, animal classes, and functional groups. We performed a comprehensive meta-analysis covering 198 field and laboratory studies reporting a total of 3624 observations of invasive plant effects on animals. Invasive plants had reducing (56%) or neutral (44%) effects on animal abundance, diversity, fitness, and ecosystem function across different ecosystems, animal classes, and feeding types while we could not find any increasing effect. Most importantly, we found that invasive plants reduced overall animal abundance, diversity and fitness. However, this significant overall effect was contingent on ecosystems, taxa, and feeding types of animals. Decreasing effects of invasive plants were most evident in riparian ecosystems, possibly because frequent disturbance facilitates more intense plant invasions compared to other ecosystem types. In accordance with their immediate reliance on plants for food, invasive plant effects were strongest on herbivores. Regarding taxonomic groups, birds and insects were most strongly affected. In insects, this may be explained by their high frequency of herbivory, while birds demonstrate that invasive plant effects can also cascade up to secondary consumers. Since data on impacts of invasive plants are rather limited for many animal groups in most ecosystems, we argue for overcoming gaps in knowledge and for a more differentiated discussion on effects of invasive plant on native fauna. © 2015 John Wiley & Sons Ltd.

  1. Mechanisms of Invasion Resistance of Aquatic Plant Communities

    Science.gov (United States)

    Petruzzella, Antonella; Manschot, Johan; van Leeuwen, Casper H. A.; Grutters, Bart M. C.; Bakker, Elisabeth S.

    2018-01-01

    Invasive plant species are among the major threats to freshwater biodiversity. Few experimental studies have investigated whether native plant diversity can provide biotic resistance to invaders in freshwater ecosystems. At small spatial scales, invasion resistance may increase with plant species richness due to a better use of available resources, leaving less available for a potential invader (Complementarity effect) and/or the greater probability to have a highly competitive (or productive) native species in the community (Selection effect). In submerged aquatic plant communities, we tested the following hypotheses: (1) invader establishment success is greatest in the absence of a native plant community; (2) lower in plant communities with greater native species richness, due to complementary and/or selection effects; and (3) invader establishment success would be lowest in rooted plant communities, based on the limiting similarity theory as the invader is a rooted submerged species. In a greenhouse experiment, we established mesocosms planted with 0 (bare sediment), 1, 2, and 4 submerged plant species native to NW Europe and subjected these to the South African invader Lagarosiphon major (Ridl.) Moss. We used two rooted (Myriophyllum spicatum L., Potamogeton perfoliatus L.) and two non-rooted native species (Ceratophyllum demersum L., Utricularia vulgaris L.) representing two distinct functional groups considering their nutrient acquisition strategy which follows from their growth form, with, respectively, the sediment and water column as their main nutrient source. We found that the presence of native vegetation overall decreased the establishment success of an alien aquatic plant species. The strength of this observed biotic resistance increased with increasing species richness of the native community. Mainly due to a selection effect, the native biomass of mixed communities overyielded, and this further lowered the establishment success of the invader in our

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

    Science.gov (United States)

    Kristine M Averill; David A Mortensen; Erica A H Smithwick; Susan Kalisz; William J McShea; Norman A Bourg; John D Parker; Alejandro A Royo; Marc D Abrams; David K Apsley; Bernd Blossey; Douglas H Boucher; Kai L Caraher; Antonio DiTommaso; Sarah E Johnson; Robert Masson; Victoria A. Nuzzo

    2017-01-01

    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...

  3. Accidental introductions are an important source of invasive plants in the continental United States.

    Science.gov (United States)

    Lehan, Nora E; Murphy, Julia R; Thorburn, Lukas P; Bradley, Bethany A

    2013-07-01

    Preventing new plant invasions is critical for reducing large-scale ecological change. Most studies have focused on the deliberate introduction of nonnatives via the ornamental plant trade. However, accidental introduction may be an important source of nonnative, invasive plants. Using Web and literature searches, we compiled pathways of introduction to the United States for 1112 nonnative plants identified as invasive in the continental United States. We assessed how the proportion of accidentally and deliberately introduced invasive plants varies over time and space and by growth habit across the lower 48 states. Deliberate introductions of ornamentals are the primary source of invasive plants in the United States, but accidental introductions through seed contaminants are an important secondary source. Invasive forbs and grasses are the most likely to have arrived accidentally through seed contaminants, while almost all nonnative, invasive trees were introduced deliberately. Nonnative plants invading eastern states primarily arrived deliberately as ornamentals, while a high proportion of invasive plants in western states arrived accidentally as seed contaminants. Accidental introductions may be increasing in importance through time. Before 1850, 10 of 89 (11%) of invasive plants arrived accidentally. After 1900, 20 of 65 (31%) arrived accidentally. Recently enacted screening protocols and weed risk assessments aim to reduce the number of potentially invasive species arriving to the United States via deliberate introduction pathways. Increasing proportions of accidentally introduced invasive plants, particularly associated with contaminated seed imports across the western states, suggest that accidental introduction pathways also need to be considered in future regulatory decisions.

  4. 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.

  5. 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.

  6. 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...

  7. Invasive alien plants benefit more from clonal integration in heterogeneous environments than natives.

    Science.gov (United States)

    Wang, Yong-Jian; Müller-Schärer, Heinz; van Kleunen, Mark; Cai, Ai-Ming; Zhang, Ping; Yan, Rong; Dong, Bi-Cheng; Yu, Fei-Hai

    2017-12-01

    What confers invasive alien plants a competitive advantage over native plants remains open to debate. Many of the world's worst invasive alien plants are clonal and able to share resources within clones (clonal integration), particularly in heterogeneous environments. Here, we tested the hypothesis that clonal integration benefits invasive clonal plants more than natives and thus confers invasives a competitive advantage. We selected five congeneric and naturally co-occurring pairs of invasive alien and native clonal plants in China, and grew pairs of connected and disconnected ramets under heterogeneous light, soil nutrient and water conditions that are commonly encountered by alien plants during their invasion into new areas. Clonal integration increased biomass of all plants in all three heterogeneous resource environments. However, invasive plants benefited more from clonal integration than natives. Consequently, invasive plants produced more biomass than natives. Our results indicate that clonal integration may confer invasive alien clonal plants a competitive advantage over natives. Therefore, differences in the ability of clonal integration could potentially explain, at least partly, the invasion success of alien clonal plants in areas where resources are heterogeneously distributed. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  8. 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

  9. Conceptualising the economics of plant health protection against invasive pests

    Directory of Open Access Journals (Sweden)

    J. HEIKKILÄ

    2008-12-01

    Full Text Available Threats to animal and plant health by invading organisms are increasing due to trade liberalisation and increased movement of goods and people. This paper conceptualises an economic approach to protecting plant health against invasive organisms, specifically addressing a multidisciplinary audience involved in plant health research and in governmental policy-making process. We discuss the conceptual framework and present some generally available management options. We also build a basic model dealing with pre-emptive and reactive control, followed by a numerical illustration to the case of Colorado potato beetle in Finland. The analysis undertaken supports the notion that pre-emptive control is a viable strategy. Reactive control should be considered only if very low invasion magnitude combines with a low level of damage. However, the strategy choice implies also distributional impacts that warrant attention. The analysis results in a solution for a given set of numbers only. Uncertainty is incorporated through sensitivity analysis. The approach presented demonstrates the basic economic thinking behind the issue, and the concepts described allow further development of more sophisticated forms of analysis.;

  10. 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

  11. Shifting global invasive potential of European plants with climate change.

    Science.gov (United States)

    Peterson, A Townsend; Stewart, Aimee; Mohamed, Kamal I; Araújo, Miguel B

    2008-06-18

    Global climate change and invasions by nonnative species rank among the top concerns for agents of biological loss in coming decades. Although each of these themes has seen considerable attention in the modeling and forecasting communities, their joint effects remain little explored and poorly understood. We developed ecological niche models for 1804 species from the European flora, which we projected globally to identify areas of potential distribution, both at present and across 4 scenarios of future (2055) climates. As expected from previous studies, projections based on the CGCM1 climate model were more extreme than those based on the HadCM3 model, and projections based on the a2 emissions scenario were more extreme than those based on the b2 emissions scenario. However, less expected were the highly nonlinear and contrasting projected changes in distributional areas among continents: increases in distributional potential in Europe often corresponded with decreases on other continents, and species seeing expanding potential on one continent often saw contracting potential on others. In conclusion, global climate change will have complex effects on invasive potential of plant species. The shifts and changes identified in this study suggest strongly that biological communities will see dramatic reorganizations in coming decades owing to shifting invasive potential by nonnative species.

  12. 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.

  13. Shifting global invasive potential of European plants with climate change.

    Directory of Open Access Journals (Sweden)

    A Townsend Peterson

    Full Text Available Global climate change and invasions by nonnative species rank among the top concerns for agents of biological loss in coming decades. Although each of these themes has seen considerable attention in the modeling and forecasting communities, their joint effects remain little explored and poorly understood. We developed ecological niche models for 1804 species from the European flora, which we projected globally to identify areas of potential distribution, both at present and across 4 scenarios of future (2055 climates. As expected from previous studies, projections based on the CGCM1 climate model were more extreme than those based on the HadCM3 model, and projections based on the a2 emissions scenario were more extreme than those based on the b2 emissions scenario. However, less expected were the highly nonlinear and contrasting projected changes in distributional areas among continents: increases in distributional potential in Europe often corresponded with decreases on other continents, and species seeing expanding potential on one continent often saw contracting potential on others. In conclusion, global climate change will have complex effects on invasive potential of plant species. The shifts and changes identified in this study suggest strongly that biological communities will see dramatic reorganizations in coming decades owing to shifting invasive potential by nonnative species.

  14. Habitat invasions by alien plants: a quantitative comparison among Mediterranean, subcontinental and oceanic regions of Europe

    OpenAIRE

    Chytrý, Milan; Maskell, Lindsay C; Pino, Joan; Pyšek, Petr; Vilà, Montserrat; Font, Xavier; Smart, Simon M.

    2008-01-01

    1. Although invasions by alien plants are major threats to the biodiversity of natural habitats, individual habitats vary considerably in their susceptibility to invasion. Therefore the risk assessment procedures, which are used increasingly by environmental managers to inform effective planning of invasive plant control, require reliable quantitative information on the extent to which different habitats are susceptible to invasion. It is also important to know whether the leve...

  15. Distribution of invasive plants in the Nitra river basin: threats and benefits for food production

    Directory of Open Access Journals (Sweden)

    Alexander Fehér

    2016-12-01

    Full Text Available Invasive plants are introduced multicellular organisms of the kingdom Plantae, which produce their food by photosynthesis. An invasive plant has the ability to thrive and spread aggressively outside its native range. A naturally aggressive plant may be especially invasive when it is introduced to a new habitat. The basic literature emphasizes mainly the ecological and environmental effects of invasive plants. Impacts of these plants on the food production have never been studied in details. The direct and indirect or potential effects of occurrence of invasive plants on food production have been analysed on basis of published data according to eight selected criteria: food, fodder for animals, food and drink additives, indirect support for food production, weeds on arable lands, meadow weeds, allergenic plants in food and toxic plants. The principal components analysis of habitat preferences of invasive plants in the Nitra river basin showed that the majority of invasive plants growing along rivers is edible (Fallopia spp., Helianthus tuberosus, Impatiens glandulifera and invasive plants preferring drier agricultural fields or grasslands are toxic and/or allergenic with low or zero level of edibility (Ambrosia artemisiifolia, Heracleum mantegazzianum. The plants living in drier conditions may produce more toxins to protect the sources (eg. water in their tissues than plants near water flows where there is abundance of sources.

  16. 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.

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

    Science.gov (United States)

    Cynthia Huebner; Cassandra Olson; Heather 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 identifi...

  18. 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...

  19. 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.

  20. 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.

  1. Mutualism between co-introduced species facilitates invasion and alters plant community structure

    Science.gov (United States)

    Prior, Kirsten M.; Robinson, Jennifer M.; Meadley Dunphy, Shannon A.; Frederickson, Megan E.

    2015-01-01

    Generalized mutualisms are often predicted to be resilient to changes in partner identity. Variation in mutualism-related traits between native and invasive species however, can exacerbate the spread of invasive species (‘invasional meltdown’) if invasive partners strongly interact. Here we show how invasion by a seed-dispersing ant (Myrmica rubra) promotes recruitment of a co-introduced invasive over native ant-dispersed (myrmecochorous) plants. We created experimental communities of invasive (M. rubra) or native ants (Aphaenogaster rudis) and invasive and native plants and measured seed dispersal and plant recruitment. In our mesocosms, and in laboratory and field trials, M. rubra acted as a superior seed disperser relative to the native ant. By contrast, previous studies have found that invasive ants are often poor seed dispersers compared with native ants. Despite belonging to the same behavioural guild, seed-dispersing ants were not functionally redundant. Instead, native and invasive ants had strongly divergent effects on plant communities: the invasive plant dominated in the presence of the invasive ant and the native plants dominated in the presence of the native ant. Community changes were not due to preferences for coevolved partners: variation in functional traits of linked partners drove differences. Here, we show that strongly interacting introduced mutualists can be major drivers of ecological change. PMID:25540283

  2. 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.

  3. The development of a plant risk evaluation (PRE tool for assessing the invasive potential of ornamental plants.

    Directory of Open Access Journals (Sweden)

    Christiana Conser

    Full Text Available 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 tool for ornamental plants. The 19 questions in the final PRE tool were narrowed down from 56 original questions from existing WRA tools. We evaluated the 56 WRA questions by screening 21 known invasive and 14 known non-invasive ornamental plants. After statistically comparing the predictability of each question and the frequency the question could be answered for both invasive and non-invasive species, we eliminated questions that provided no predictive power, were irrelevant in our current model, or could not be answered reliably at a high enough percentage. We also combined many similar questions. The final 19 remaining PRE questions were further tested for accuracy using 56 additional known invasive plants and 36 known non-invasive ornamental species. The resulting evaluation demonstrated that when "needs further evaluation" classifications were not included, the accuracy of the model was 100% for both predicting invasiveness and non-invasiveness. When "needs further evaluation" classifications were included as either false positive or false negative, the model was still 93% accurate in predicting invasiveness and 97% accurate in predicting non-invasiveness, with an overall accuracy of 95%. We conclude that the PRE tool should not only provide growers with a method to accurately screen their current stock and potential new introductions, but also increase the probability of the tool being accepted for use by the industry as the basis for a nursery

  4. The development of a plant risk evaluation (PRE) tool for assessing the invasive potential of ornamental plants.

    Science.gov (United States)

    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) tool for ornamental plants. The 19 questions in the final PRE tool were narrowed down from 56 original questions from existing WRA tools. We evaluated the 56 WRA questions by screening 21 known invasive and 14 known non-invasive ornamental plants. After statistically comparing the predictability of each question and the frequency the question could be answered for both invasive and non-invasive species, we eliminated questions that provided no predictive power, were irrelevant in our current model, or could not be answered reliably at a high enough percentage. We also combined many similar questions. The final 19 remaining PRE questions were further tested for accuracy using 56 additional known invasive plants and 36 known non-invasive ornamental species. The resulting evaluation demonstrated that when "needs further evaluation" classifications were not included, the accuracy of the model was 100% for both predicting invasiveness and non-invasiveness. When "needs further evaluation" classifications were included as either false positive or false negative, the model was still 93% accurate in predicting invasiveness and 97% accurate in predicting non-invasiveness, with an overall accuracy of 95%. We conclude that the PRE tool should not only provide growers with a method to accurately screen their current stock and potential new introductions, but also increase the probability of the tool being accepted for use by the industry as the basis for a nursery certification program.

  5. [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.

  6. Region-specific patterns and drivers of macroscale forest plant invasions

    Science.gov (United States)

    Basil V. Iannone; Christopher M. Oswalt; Andrew M. Liebhold; Qinfeng Guo; Kevin M. Potter; Gabriela C. Nunez-Mir; Sonja N. Oswalt; Bryan C. Pijanowski; Songlin Fei; Bethany Bradley

    2015-01-01

    Aim Stronger inferences about biological invasions may be obtained when accounting for multiple invasion measures and the spatial heterogeneity occurring across large geographic areas. We pursued this enquiry by utilizing a multimeasure, multiregional framework to investigate forest plant invasions at a subcontinental scale. ...

  7. Characteristics of information available on fire and invasive plants in the eastern United States

    Science.gov (United States)

    Corey L. Gucker; Kris Zouhar; Jane Kapler Smith; Katharine R. Stone

    2012-01-01

    Wildland managers need detailed information about the responses of invasive species to fire and the conditions that increase site invasibility in order to effectively manage fire without introducing or increasing populations of invasive plants. Literature reviews and syntheses of original research are important sources of this information, but the usefulness of a...

  8. Invasive plants transform the three-dimensional structure of rain forests

    Science.gov (United States)

    Gegory P. Asner; R. Flint Hughes; Peter M. Vitousek; David E. Knapp; Ty Kennedy-Bowdoin; Joseph Boardman; Roberta E. Martin; Michael Eastwood; Robert O. Green

    2008-01-01

    Biological invasions contribute to global environmental change, but the dynamics and consequences of most invasions are difficult to assess at regional scales. We deployed an airborne remote sensing system that mapped the location and impacts of five highly invasive plant species across 221,875 ha of Hawaiian ecosystems, identifying four distinct ways that these...

  9. Invasive plants, insects, and diseases in the forests of the Anthropocene

    Science.gov (United States)

    Alexander M. Evans

    2014-01-01

    Invasive species, non-native plants, insects, and diseases can devastate forests. They outcompete native species, replace them in the ecosystem, and even drive keystone forest species to functional extinction. Invasives have negative effects on forest hydrology, carbon storage, and nutrient cycling. The damage caused by invasive species exacerbates the other forest...

  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. 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...

  12. 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.

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

    Science.gov (United States)

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

    2010-01-01

    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...

  14. 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.

  15. Genetic variation in anti-herbivore chemical defenses in an invasive plant

    Science.gov (United States)

    Plants produce a variety of secondary metabolites such as flavonoids (qualitative defense) or tannins (quantitative defense), that vary in effectiveness against different herbivores. Because invasive plants experience different herbivore interactions in their introduced versus native ranges, they ma...

  16. 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....

  17. 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...

  18. 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

    2017-01-01

    Abstract 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 (Tc) 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) (DTRsym), asymmetric warming with increased (DTRinc) and decreased (DTRdec) DTR. The warming treatments did not affect seed germination of invasive species under any of the conditions, but DTRsym and DTRinc 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 DTRsym and DTRinc 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 DTRsym, DTRdec decreased the biomass of both the invasive

  19. Would the control of invasive alien plants reduce malaria transmission? A review.

    Science.gov (United States)

    Stone, Christopher M; Witt, Arne B R; Walsh, Guillermo Cabrera; Foster, Woodbridge A; Murphy, Sean T

    2018-02-01

    Vector control has been the most effective preventive measure against malaria and other vector-borne diseases. However, due to concerns such as insecticide resistance and budget shortfalls, an integrated control approach will be required to ensure sustainable, long-term effectiveness. An integrated management strategy should entail some aspects of environmental management, relying on coordination between various scientific disciplines. Here, we review one such environmental control tactic: invasive alien plant management. This covers salient plant-mosquito interactions for both terrestrial and aquatic invasive plants and how these affect a vector's ability to transmit malaria. Invasive plants tend to have longer flowering durations, more vigorous growth, and their spread can result in an increase in biomass, particularly in areas where previously little vegetation existed. Some invasive alien plants provide shelter or resting sites for adult mosquitoes and are also attractive nectar-producing hosts, enhancing their vectorial capacity. We conclude that these plants may increase malaria transmission rates in certain environments, though many questions still need to be answered, to determine how often this conclusion holds. However, in the case of aquatic invasive plants, available evidence suggests that the management of these plants would contribute to malaria control. We also examine and review the opportunities for large-scale invasive alien plant management, including options for biological control. Finally, we highlight the research priorities that must be addressed in order to ensure that integrated vector and invasive alien plant management operate in a synergistic fashion.

  20. Increased seed consumption by biological control weevil tempers positive CO2 effect on invasive plant (Centaurea diffusa) fitness

    Science.gov (United States)

    Predicted increases in atmospheric CO2 and temperature may benefit some invasive plants, increasing the need for effective invasive plant management. Biological control can be an effective means of managing invasive plants, but the varied responses of plant-insect interactions to climate change make...

  1. 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

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

    CSIR Research Space (South Africa)

    Chamier, J

    2012-04-01

    Full Text Available . The biomass inputs of alien invasive plants, especially nitrogen fixers such as Acacia spp., alter nutrient cycles and can elevate nutrient concentrations in groundwater. Alien plant invasions alter the fire regimes in invaded areas by changing the size...

  3. Distribution, density and impact of invasive plants in Lake Nakuru National Park, Kenya

    NARCIS (Netherlands)

    Ngweno, C.C.; Mwasi, S.M.; Kairu, J.K.

    2010-01-01

    Invasive plants have invaded swathes of grasslands in Lake Nakuru National Park thus necessitating the Park management to institute measures to control them. Despite this, information on the status and impact of invasive plants in these grasslands is lacking. Six grassland types were identified and

  4. Chapter 12: Gaps in scientific knowledge about fire and nonnative invasive plants

    Science.gov (United States)

    Kristin Zouhar; Gregory T. Munger; Jane Kapler Smith

    2008-01-01

    The potential for nonnative, invasive plants to alter an ecosystem depends on species traits, ecosystem characteristics, and the effects of disturbances, including fire. This study identifies gaps in science-based knowledge about the relationships between fire and nonnative invasive plants in the United States. The literature was searched for information on 60...

  5. Ecological effects of the Hayman Fire - Part 7: Key invasive nonnative plants

    Science.gov (United States)

    Geneva Chong; Tom Stohlgren; Catherine Crosier; Sara Simonson; Greg Newman; Eric Petterson

    2003-01-01

    Invasive, nonnative plant species pose one of the greatest potential threats to long-term ecosystem integrity in the area burned by the 2002 Hayman Fire. In other ecosystems, nonnative invaders have been shown to cause decline of native plant species and pollinators, as well as adverse changes in fire regimes, nutrient cycling, and hydrology. Thus, invasive, nonnative...

  6. Determining a charge for the clearing of invasive alien plant species ...

    African Journals Online (AJOL)

    South Africa is running out of water supply options. One option, however, is to control invasive alien plant species (IAPs) within water catchment areas and in riparian zones. The National Water Act and subsequent documentation provide a guide for the use of economic instruments to manage invasive alien plant species at ...

  7. 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...

  8. Invasive alien plants in South Africa: how well do we understand the ecological impacts?

    CSIR Research Space (South Africa)

    Richardson, DM

    2004-01-01

    Full Text Available This paper examines the evidence for the effects of invasive alien plants in natural and semi-natural ecosystems in South Africa. Invasive alien plants are concentrated in the Western Cape, along the eastern seaboard, and into the eastern interior...

  9. 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 ...

  10. 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.

  11. 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

  12. 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

    2015-10-22

    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.

  13. 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.

  14. 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

  15. Live plant imports: the major pathway for forest insect and pathogen invasions of the US

    Science.gov (United States)

    Andrew M. Liebhold; Eckehard G. Brockerhoff; Lynn J. Garrett; Jennifer L. Parke

    2012-01-01

    Trade in live plants has been recognized worldwide as an important invasion pathway for non-native plant pests. Such pests can have severe economic and ecological consequences. Nearly 70% of damaging forest insects and pathogens established in the US between 1860 and 2006 most likely entered on imported live plants. The current regulation of plant imports is outdated...

  16. 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.

  17. Direct and indirect effects of invasive plants on soil chemistry and ecosystem function.

    Science.gov (United States)

    Weidenhamer, Jeffrey D; Callaway, Ragan M

    2010-01-01

    Invasive plants have a multitude of impacts on plant communities through their direct and indirect effects on soil chemistry and ecosystem function. For example, plants modify the soil environment through root exudates that affect soil structure, and mobilize and/or chelate nutrients. The long-term impact of litter and root exudates can modify soil nutrient pools, and there is evidence that invasive plant species may alter nutrient cycles differently from native species. The effects of plants on ecosystem biogeochemistry may be caused by differences in leaf tissue nutrient stoichiometry or secondary metabolites, although evidence for the importance of allelochemicals in driving these processes is lacking. Some invasive species may gain a competitive advantage through the release of compounds or combinations of compounds that are unique to the invaded community—the “novel weapons hypothesis.” Invasive plants also can exert profound impact on plant communities indirectly through the herbicides used to control them. Glyphosate, the most widely used herbicide in the world, often is used to help control invasive weeds, and generally is considered to have minimal environmental impacts. Most studies show little to no effect of glyphosate and other herbicides on soil microbial communities. However, herbicide applications can reduce or promote rhizobium nodulation and mycorrhiza formation. Herbicide drift can affect the growth of non-target plants, and glyphosate and other herbicides can impact significantly the secondary chemistry of plants at sublethal doses. In summary, the literature indicates that invasive species can alter the biogeochemistry of ecosystems, that secondary metabolites released by invasive species may play important roles in soil chemistry as well as plant-plant and plant-microbe interactions, and that the herbicides used to control invasive species can impact plant chemistry and ecosystems in ways that have yet to be fully explored.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Climate warming affects biological invasions by shifting interactions of plants and herbivores.

    Science.gov (United States)

    Lu, Xinmin; Siemann, Evan; Shao, Xu; Wei, Hui; Ding, Jianqing

    2013-08-01

    Plants and herbivorous insects can each be dramatically affected by temperature. Climate warming may impact plant invasion success directly but also indirectly through changes in their natural enemies. To date, however, there are no tests of how climate warming shifts the interactions among invasive plants and their natural enemies to affect invasion success. Field surveys covering the full latitudinal range of invasive Alternanthera philoxeroides in China showed that a beetle introduced for biocontrol was rare or absent at higher latitudes. In contrast, plant cover and mass increased with latitude. In a 2-year field experiment near the northern limit of beetle distribution, we found the beetle sustained populations across years under elevated temperature, dramatically decreasing A. philoxeroides growth, but it failed to overwinter in ambient temperature. Together, these results suggest that warming will allow the natural enemy to expand its range, potentially benefiting biocontrol in regions that are currently too cold for the natural enemy. However, the invader may also expand its range further north in response to warming. In such cases where plants tolerate cold better than their natural enemies, the geographical gap between plant and herbivorous insect ranges may not disappear but will shift to higher latitudes, leading to a new zone of enemy release. Therefore, warming will not only affect plant invasions directly but also drive either enemy release or increase that will result in contrasting effects on invasive plants. The findings are also critical for future management of invasive species under climate change. © 2013 John Wiley & Sons Ltd.

  3. 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

  4. 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...... observed to be species and community combination specific. This evolutionary study represents a novel in silico attempt to tackle invasiveness in an experimental framework, and may provide a new methodology for tackling these issues....

  5. Comparative water use of native and invasive plants at multiple scales: a global meta-analysis.

    Science.gov (United States)

    Cavaleri, Molly A; Sack, Lawren

    2010-09-01

    Ecohydrology and invasive ecology have become increasingly important in the context of global climate change. This study presents the first in-depth analysis of the water use of invasive and native plants of the same growth form at multiple scales: leaf, plant, and ecosystem. We reanalyzed data for several hundred native and invasive species from over 40 published studies worldwide to glean global trends and to highlight how patterns vary depending on both scale and climate. We analyzed all pairwise combinations of co-occurring native and invasive species for higher comparative resolution of the likelihood of an invasive species using more water than a native species and tested for significance using bootstrap methods. At each scale, we found several-fold differences in water use between specific paired invasive and native species. At the leaf scale, we found a strong tendency for invasive species to have greater stomatal conductance than native species. At the plant scale, however, natives and invasives were equally likely to have the higher sap flow rates. Available data were much fewer for the ecosystem scale; nevertheless, we found that invasive-dominated ecosystems were more likely to have higher sap flow rates per unit ground area than native-dominated ecosystems. Ecosystem-scale evapotranspiration, on the other hand, was equally likely to be greater for systems dominated by invasive and native species of the same growth form. The inherent disconnects in the determination of water use when changing scales from leaf to plant to ecosystem reveal hypotheses for future studies and a critical need for more ecosystem-scale water use measurements in invasive- vs. native-dominated systems. The differences in water use of native and invasive species also depended strongly on climate, with the greater water use of invasives enhanced in hotter, wetter climates at the coarser scales.

  6. 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: Notice of intent to prepare an environmental impact statement. SUMMARY: Invasive plants are currently... management techniques became available with the Pacific Northwest Region Invasive Plant Program, Preventing...

  7. Costs and benefits of biological control of invasive alien plants in South Africa

    CSIR Research Space (South Africa)

    Van Wilgen, BW

    2011-08-01

    Full Text Available and benefits of biological control of invasive alien plants in South Africa B.W. van Wilgen* & W.J. De Lange Centre for Invasion Biology, CSIR Natural Resources and the Environment, P.O. Box 320, Stellenbosch, 7599 South Africa This paper provides a brief..., and economic and recre- ational activities Grazing resources. Invasive alien plants have significant effects on grazing resources. Range- lands that are utilized by both domestic livestock and wildlife have become invaded by several alien plant species...

  8. Novel chemistry of invasive plants: exotic species have more unique metabolomic profiles than native congeners

    NARCIS (Netherlands)

    Macel, M.; de Vos, R.C.H.; Jansen, J.J.; Van der Putten, W.H.; Van Dam, N.M.

    2014-01-01

    t 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

  9. Novel chemistry of invasive plants: exotic species have more unique metabolomic profiles than native congeners

    NARCIS (Netherlands)

    Macel, M.; Vos, de R.C.H.; Jansen, J.J.; Putten, van der W.H.; Dam, van N.M.

    2014-01-01

    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

  10. A Survey of the Invasive Aquatic and Riparian Plants of the Lower Rio Grande

    Science.gov (United States)

    2005-04-01

    potentially damaging plant species were observed. These included giant cane (Arundo donax) (Figure 5), elephant- ear ( Colocasia esculenta) (Figure 6...Brownsville, TX). Hydrilla, a nonindigenous aquatic plant species , has been implicated in restricted water delivery, inaccurate water accounting, and an...the distribution and expansion of the hydrilla infestations and document the presence of other invasive aquatic and riparian plant species . Several

  11. The rhizosphere microbiota of plant invaders: an overview of recent advances in the microbiomics of invasive plants.

    Science.gov (United States)

    Coats, Vanessa C; Rumpho, Mary E

    2014-01-01

    Plants in terrestrial systems have evolved in direct association with microbes functioning as both agonists and antagonists of plant fitness and adaptability. As such, investigations that segregate plants and microbes provide only a limited scope of the biotic interactions that dictate plant community structure and composition in natural systems. Invasive plants provide an excellent working model to compare and contrast the effects of microbial communities associated with natural plant populations on plant fitness, adaptation, and fecundity. The last decade of DNA sequencing technology advancements opened the door to microbial community analysis, which has led to an increased awareness of the importance of an organism's microbiome and the disease states associated with microbiome shifts. Employing microbiome analysis to study the symbiotic networks associated with invasive plants will help us to understand what microorganisms contribute to plant fitness in natural systems, how different soil microbial communities impact plant fitness and adaptability, specificity of host-microbe interactions in natural plant populations, and the selective pressures that dictate the structure of above-ground and below-ground biotic communities. This review discusses recent advances in invasive plant biology that have resulted from microbiome analyses as well as the microbial factors that direct plant fitness and adaptability in natural systems.

  12. Do invasive plants structure microbial communities to accelerate decomposition in intermountain grasslands?

    Science.gov (United States)

    McTee, Michael R; Lekberg, Ylva; Mummey, Dan; Rummel, Alexii; Ramsey, Philip W

    2017-12-01

    Invasive plants are often associated with greater productivity and soil nutrient availabilities, but whether invasive plants with dissimilar traits change decomposer communities and decomposition rates in consistent ways is little known. We compared decomposition rates and the fungal and bacterial communities associated with the litter of three problematic invaders in intermountain grasslands; cheatgrass ( Bromus tectorum ), spotted knapweed ( Centaurea stoebe ) and leafy spurge ( Euphorbia esula ), as well as the native bluebunch wheatgrass ( Pseudoroegneria spicata ). Shoot and root litter from each plant was placed in cheatgrass, spotted knapweed, and leafy spurge invasions as well as remnant native communities in a fully reciprocal design for 6 months to see whether decomposer communities were species-specific, and whether litter decomposed fastest when placed in a community composed of its own species (referred to hereafter as home-field advantage-HFA). Overall, litter from the two invasive forbs, spotted knapweed and leafy spurge, decomposed faster than the native and invasive grasses, regardless of the plant community of incubation. Thus, we found no evidence of HFA. T-RFLP profiles indicated that both fungal and bacterial communities differed between roots and shoots and among plant species, and that fungal communities also differed among plant community types. Synthesis . These results show that litter from three common invaders to intermountain grasslands decomposes at different rates and cultures microbial communities that are species-specific, widespread, and persistent through the dramatic shifts in plant communities associated with invasions.

  13. Twelve invasive plant taxa in U.S. western riparian ecosystems

    Science.gov (United States)

    Assessments of stream ecosystems often include an evaluation of riparian condition; a key stressor in riparian ecosystems is the presence of invasive plants. We analyzed the distribution of 12 invasive taxa (common burdock [Arctium minus], giant reed [Arundo donax], cheatgrass [B...

  14. Cooperative prevention systems to protect rangelands from the spread of invasive plants

    Science.gov (United States)

    Invasive plants continue to spread and impact rangelands in the western United States. Fortunately, many rangeland ecosystems still remain invasive weed-free.Cooperative prevention systems can safeguard these remaining areas. Local-level weed prevention areas (WPAs) prioritize prevention in the larg...

  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. Invasion resistance and persistence: established plants win, even with disturbance and high propagule pressure

    Science.gov (United States)

    Christopher M. McGlone; Carolyn Hull Sieg; Thomas E. Kolb

    2011-01-01

    Disturbances and propagule pressure are key mechanisms in plant community resistance to invasion, as well as persistence of invasions. Few studies, however, have experimentally tested the interaction of these two mechanisms. We initiated a study in a southwestern ponderosa pine (Pinus ponderosa Laws.)/bunch grass system to determine the susceptibility of remnant native...

  17. Invasive plant species in lawns of Belgrade roads | Stavretović ...

    African Journals Online (AJOL)

    In this paper the presence of invasive and potentially invasive plant species in lawns of roads in Belgrade, the capital city of the Republic of Serbia was analysed. The following lawn categories were selected for the purpose of analysis: the lawns of traffic roundabouts, the lane-dividing lawns, the lawns around roads and ...

  18. Insects mediate the effects of propagule supply and resource availability on a plant invasion

    Science.gov (United States)

    Nathan J. Sanders; Jake F. Weltzin; Gregory M. Crutsinger; Matthew C. Fitzpatrick; Martin A. Nunez; Christopher M. Oswalt; Kristin E. Lane

    2007-01-01

    Invasive species are a global threat to biodiversity and the functioning of natural ecosystems. Here, we report on a two-year experiment aimed at elucidating the combined and relative effects of three key controls on plant invasions: propagule supply, soil nitrogen (N) availability, and herbivory by native insects. We focus on the exotic species Lespedeza...

  19. 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 impacts on water resources. The number of invasive species considered was restricted to those with extensive current or potential distributions; 17 out of a possible 160 species in fynbos shrublands in this case. We estimate that invasive alien plants...

  20. Ain't no mountain high enough: plant invasions reaching new elevations

    Science.gov (United States)

    An& iacute Pauchard; bal; Christoph Kueffer; Hansj& ouml Dietz; rg; Curtis C. Daehler; Jake Alexander; Peter J. Edwards; Ar& eacute; Jos& eacute valo; Ram& oacute; n; Lohengrin A. Cavieres; Antoine Guisan; Sylvia Haider; Gabi Jakobs; Keith McDougall; Constance I. Millar; Bridgett J. Naylor; Catherine G. Parks; Lisa J. Rew; Tim Seipel

    2009-01-01

    Most studies of invasive species have been in highly modified, lowland environments, with comparatively little attention directed to less disturbed, high-elevation environments. However, increasing evidence indicates that plant invasions do occur in these environments, which often have high conservation value and provide important ecosystem services. Over a thousand...

  1. Alien plant invasions in South Africa: driving forces and the human dimension

    CSIR Research Space (South Africa)

    Le Maitre, David C

    2004-01-01

    Full Text Available Invasive alien plants pose a substantial threat to the rich biodiversity of South Africa, and to the sustained delivery of a wide range of ecosystem services. Biological invasions are driven by human activities and mediated by culturally shaped...

  2. A new perspective on trait differences between native and invasive exotic plants.

    Science.gov (United States)

    Leffler, A Joshua; James, Jeremy J; Monaco, Thomas A; Sheley, Roger L

    2014-02-01

    Functional differences between native and exotic species potentially constitute one factor responsible for plant invasion. Differences in trait values between native and exotic invasive species, however, should not be considered fixed and may depend on the context of the comparison. Furthermore, the magnitude of difference between native and exotic species necessary to trigger invasion is unknown. We propose a criterion that differences in trait values between a native and exotic invasive species must be greater than differences between co-occurring natives for this difference to be ecologically meaningful and a contributing factor to plant invasion. We used a meta-analysis to quantify the difference between native and exotic invasive species for various traits examined in previous studies and compared this value to differences among native species reported in the same studies. The effect size between native and exotic invasive species was similar to the effect size between co-occurring natives except for studies conducted in the field; in most instances, our criterion was not met although overall differences between native and exotic invasive species were slightly larger than differences between natives. Consequently, trait differences may be important in certain contexts, but other mechanisms of invasion are likely more important in most cases. We suggest that using trait values as predictors of invasion will be challenging.

  3. 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...

  4. 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...

  5. 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.

  6. Invasive stink bug favors naïve plants: Testing the role of plant geographic origin in diverse, managed environments.

    Science.gov (United States)

    Martinson, Holly M; Bergmann, Erik J; Venugopal, P Dilip; Riley, Christopher B; Shrewsbury, Paula M; Raupp, Michael J

    2016-09-01

    With the introduction and establishment of exotic species, most ecosystems now contain both native and exotic plants and herbivores. Recent research identifies several factors that govern how specialist herbivores switch host plants upon introduction. Predicting the feeding ecology and impacts of introduced generalist species, however, remains difficult. Here, we examine how plant geographic origin, an indicator of shared co-evolutionary history, influences patterns of host use by a generalist, invasive herbivore, while accounting for variation in plant availability. The brown marmorated stink bug, Halyomorpha halys, is a highly polyphagous Asian herbivore and an economically important invasive pest in North America and Europe. In visual surveys of 220 plant taxa in commercial nurseries in Maryland, USA, H. halys was more abundant on non-Asian plants and selected these over Asian plants. The relationship between the relative use of plants and their availability was strongly positive but depended also on plant origin at two of our three sites, where the higher relative use of non-Asian plants was greatest for highly abundant taxa. These results highlight the importance of considering both plant origin and relative abundance in understanding the selection of host plants by invasive generalist herbivores in diverse, natural and urban forests.

  7. Strong Response of an Invasive Plant Species (Centaurea solstitialis L.) to Global Environmental Changes.

    OpenAIRE

    Dukes, Jeffrey; Chiariello, Nona R; Loarie, Scott R; Field, Christopher B

    2011-01-01

    Global environmental changes are altering interactions among plant species, sometimes favoring invasive species. Here, we examine how a suite of five environmental factors, singly and in combination, can affect the success of a highly invasive plant. We introduced Centaurea solstitialis L. (yellow starthistle), which is considered by many to be California’s most troublesome wildland weed, to grassland plots in the San Francisco Bay Area. These plots experienced ambient or elevated levels of wa...

  8. Response to enemies in the invasive plant Lythrum salicaria is genetically determined

    Science.gov (United States)

    Joshi, Srijana; Tielbörger, Katja

    2012-01-01

    Background and Aims The enemy release hypothesis assumes that invasive plants lose their co-evolved natural enemies during introduction into the new range. This study tested, as proposed by the evolution of increased competitive ability (EICA) hypothesis, whether escape from enemies results in a decrease in defence ability in plants from the invaded range. Two straightforward aspects of the EICA are examined: (1) if invasives have lost their enemies and their defence, they should be more negatively affected by their full natural pre-invasion herbivore spectrum than their native conspecifics; and (2) the genetic basis of evolutionary change in response to enemy release in the invasive range has not been taken sufficiently into account. Methods Lythrum salicaria (purple loosestrife) from several populations in its native (Europe) and invasive range (North America) was exposed to all above-ground herbivores in replicated natural populations in the native range. The experiment was performed both with plants raised from field-collected seeds as well as with offspring of these where maternal effects were removed. Key Results Absolute and relative leaf damage was higher for introduced than for native plants. Despite having smaller height growth rate, invasive plants attained a much larger final size than natives irrespective of damage, indicating large tolerance rather than effective defence. Origin effects on response to herbivory and growth were stronger in second-generation plants, suggesting that invasive potential through enemy release has a genetic basis. Conclusions The findings support two predictions of the EICA hypothesis – a genetically determined difference between native and invasive plants in plant vigour and response to enemies – and point to the importance of experiments that control for maternal effects and include the entire spectrum of native range enemies. PMID:22492331

  9. Responses of two invasive plants under various microclimate conditions in the Seoul metropolitan region.

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    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 CO(2) concentrations differed significantly between the urban (14.8 °C and 439 ppm CO(2)) and suburban (13.0 °C and 427 ppm CO(2)) 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.

  10. INVASIVE PLANTS HARBOR HUNGRY DETRITIVORES THAT ALTER ECOSYSTEM FUNCTION

    Science.gov (United States)

    Ecosystems are expected to function more efficiently in response to a diverse community of inhabitants. However, biological invasions may change expected relationships between ecosystem function and diversity. We observed increased decomposition, a measure of ecosystem function...

  11. 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’...

  12. Revealing historic invasion patterns and potential invasion sites for two non-native plant species.

    Directory of Open Access Journals (Sweden)

    Jacob N Barney

    Full Text Available The historical spatio-temporal distribution of invasive species is rarely documented, hampering efforts to understand invasion dynamics, especially at regional scales. Reconstructing historical invasions through use of herbarium records combined with spatial trend analysis and modeling can elucidate spreading patterns and identify susceptible habitats before invasion occurs. Two perennial species were chosen to contrast historic and potential phytogeographies: Japanese knotweed (Polygonum cuspidatum, introduced intentionally across the US; and mugwort (Artemisia vulgaris, introduced largely accidentally to coastal areas. Spatial analysis revealed that early in the invasion, both species have a stochastic distribution across the contiguous US, but east of the 90(th meridian, which approximates the Mississippi River, quickly spread to adjacent counties in subsequent decades. In contrast, in locations west of the 90(th meridian, many populations never spread outside the founding county, probably a result of encountering unfavorable environmental conditions. Regression analysis using variables categorized as environmental or anthropogenic accounted for 24% (Japanese knotweed and 30% (mugwort of the variation in the current distribution of each species. Results show very few counties with high habitat suitability (>/=80% remain un-invaded (5 for Japanese knotweed and 6 for mugwort, suggesting these perennials are reaching the limits of large-scale expansion. Despite differences in initial introduction loci and pathways, Japanese knotweed and mugwort demonstrate similar historic patterns of spread and show declining rates of regional expansion. Invasion mitigation efforts should be concentrated on areas identified as highly susceptible that border invaded regions, as both species demonstrate secondary expansion from introduction loci.

  13. Effects of an exotic plant invasion on native understory plants in a tropical dry forest.

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    Prasad, Ayesha E

    2010-06-01

    The dry forests of southern India, which are endangered tropical ecosystems and among the world's most important tiger (Panthera tigris) habitats, are extensively invaded by exotic plants. Yet, experimental studies exploring the impacts of these invasions on native plants in these forests are scarce. Consequently, little is known about associated implications for the long-term conservation of tigers and other biodiversity in these habitats. I studied the impacts of the exotic plant Lantana camara on understory vegetation in a dry-forest tiger habitat in southern India. I compared the richness, composition, and abundance of tree seedlings, herbs, and shrubs and the abundance of grass among plots in which Lantana was cleared or left standing. These plots were distributed across two blocks-livestock free and livestock grazed. Removal of Lantana had an immediate positive effect on herb-shrub richness in the livestock-free block, but had no effect on that of tree seedlings in either livestock block. Tree-seedling and herb-shrub composition differed significantly between Lantana treatment and livestock block, and Lantana removal significantly decreased survival of tree seedlings. Nevertheless, the absence of trees, in any stage between seedling and adult, indicates that Lantana may stall tree regeneration. Lantana removal decreased the abundance of all understory strata, probably because forage plants beneath Lantana are less accessible to herbivores, and plants in Lantana-free open plots experienced greater herbivory. Reduced access to forage in invaded habitats could negatively affect ungulate populations and ultimately compromise the ability of these forests to sustain prey-dependent large carnivores. Additional research focused on understanding and mitigating threats posed by exotic plants may be crucial to the long-term protection of these forests as viable tiger habitats.

  14. Coverage of Native Plants Is Key Factor Influencing the Invasibility of Freshwater Ecosystems by Exotic Plants in China

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    Haihao Yu

    2018-02-01

    Full Text Available Understanding the biotic and abiotic factors that influence the susceptibility of a community to invasion is beneficial for the prediction and management of invasive species and the conservation of native biodiversity. However, the relationships between factors and invasibility of a community have not been fully confirmed, and the factors most associated with the susceptibility of a community to invasion have rarely been identified. In this study, we investigated the species richness patterns in aquatic exotic and native plants and the relationships of exotic species richness with habitat and water environment factors in 262 aquatic plant communities in China. A total of 11 exotic plant species were recorded in our field survey, and we found neither a negative nor a positive relationship between aquatic exotic and native plant species richness. The aquatic exotic plant species richness is negatively correlated with the relative coverage and biomass of native plants but positively correlated with the total nitrogen (TN, total phosphorus (TP, and chemical oxygen demand (COD concentrations in the water. The native plant species richness, native species’ relative coverage, and native species’ biomass were positively related to each other, whereas the TP, TN, and COD were also positively related to each other. The native plant species richness, native species’ relative coverage, and native species biomass were each negatively correlated with the TP, TN, and COD. In addition, biotic rather than abiotic predictors accounted for most of the variation in exotic plant richness. Our results suggest that improving the vegetation coverage and the biodiversity of native plants is the most effective approach for preventing alien plant invasions and minimizing their impacts on freshwater ecosystems.

  15. Coverage of Native Plants Is Key Factor Influencing the Invasibility of Freshwater Ecosystems by Exotic Plants in China.

    Science.gov (United States)

    Yu, Haihao; Wang, Ligong; Liu, Chunhua; Fan, Shufeng

    2018-01-01

    Understanding the biotic and abiotic factors that influence the susceptibility of a community to invasion is beneficial for the prediction and management of invasive species and the conservation of native biodiversity. However, the relationships between factors and invasibility of a community have not been fully confirmed, and the factors most associated with the susceptibility of a community to invasion have rarely been identified. In this study, we investigated the species richness patterns in aquatic exotic and native plants and the relationships of exotic species richness with habitat and water environment factors in 262 aquatic plant communities in China. A total of 11 exotic plant species were recorded in our field survey, and we found neither a negative nor a positive relationship between aquatic exotic and native plant species richness. The aquatic exotic plant species richness is negatively correlated with the relative coverage and biomass of native plants but positively correlated with the total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD) concentrations in the water. The native plant species richness, native species' relative coverage, and native species' biomass were positively related to each other, whereas the TP, TN, and COD were also positively related to each other. The native plant species richness, native species' relative coverage, and native species biomass were each negatively correlated with the TP, TN, and COD. In addition, biotic rather than abiotic predictors accounted for most of the variation in exotic plant richness. Our results suggest that improving the vegetation coverage and the biodiversity of native plants is the most effective approach for preventing alien plant invasions and minimizing their impacts on freshwater ecosystems.

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

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    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

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

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    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. .

  18. Natural and land-use history of the Northwest mountain ecoregions (USA) in relation to patterns of plant invasions.

    Science.gov (United States)

    Catherine G. Parks; Steven R. Radosevich; Bryan A. Endress; Bridgett J. Naylor; Dawn Anzinger; Lisa J. Rew; Bruce D. Maxwell; Kathleen A. Dwire

    2005-01-01

    Although the Northwest currently has the least proportion of non-native invasive plant species relative to other regions or North America, invasions continue to increase into the mountainous areas of the region. Landscape structure, such as the variation found along the complex gradients of the Northwest mountain ecoregions, affects the expansion of invasive plant...

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

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    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

  20. Different traits determine introduction, naturalization and invasion success in woody plants: Proteaceae as a test case.

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    Desika Moodley

    Full Text Available A major aim of invasion ecology is to identify characteristics of successful invaders. However, most plant groups studied in detail (e.g. pines and acacias have a high percentage of invasive taxa. Here we examine the global introduction history and invasion ecology of Proteaceae--a large plant family with many taxa that have been widely disseminated by humans, but with few known invaders. To do this we compiled a global list of species and used boosted regression tree models to assess which factors are important in determining the status of a species (not introduced, introduced, naturalized or invasive. At least 402 of 1674 known species (24% have been moved by humans out of their native ranges, 58 species (14% have become naturalized but not invasive, and 8 species (2% are invasive. The probability of naturalization was greatest for species with large native ranges, low susceptibility to Phytophthora root-rot fungus, large mammal-dispersed seeds, and with the capacity to resprout. The probability of naturalized species becoming invasive was greatest for species with large native ranges, those used as barrier plants, tall species, species with small seeds, and serotinous species. The traits driving invasiveness of Proteaceae were similar to those for acacias and pines. However, while some traits showed a consistent influence at introduction, naturalization and invasion, others appear to be influential at one stage only, and some have contrasting effects at different stages. Trait-based analyses therefore need to consider different invasion stages separately. On their own, these observations provide little predictive power for risk assessment, but when the causative mechanisms are understood (e.g. Phytophthora susceptibility they provide valuable insights. As such there is considerable value in seeking the correlates and mechanisms underlying invasions for particular taxonomic or functional groups.

  1. Different Traits Determine Introduction, Naturalization and Invasion Success In Woody Plants: Proteaceae as a Test Case

    Science.gov (United States)

    Moodley, Desika; Geerts, Sjirk; Richardson, David M.; Wilson, John R. U.

    2013-01-01

    A major aim of invasion ecology is to identify characteristics of successful invaders. However, most plant groups studied in detail (e.g. pines and acacias) have a high percentage of invasive taxa. Here we examine the global introduction history and invasion ecology of Proteaceae—a large plant family with many taxa that have been widely disseminated by humans, but with few known invaders. To do this we compiled a global list of species and used boosted regression tree models to assess which factors are important in determining the status of a species (not introduced, introduced, naturalized or invasive). At least 402 of 1674 known species (24%) have been moved by humans out of their native ranges, 58 species (14%) have become naturalized but not invasive, and 8 species (2%) are invasive. The probability of naturalization was greatest for species with large native ranges, low susceptibility to Phytophthora root-rot fungus, large mammal-dispersed seeds, and with the capacity to resprout. The probability of naturalized species becoming invasive was greatest for species with large native ranges, those used as barrier plants, tall species, species with small seeds, and serotinous species. The traits driving invasiveness of Proteaceae were similar to those for acacias and pines. However, while some traits showed a consistent influence at introduction, naturalization and invasion, others appear to be influential at one stage only, and some have contrasting effects at different stages. Trait-based analyses therefore need to consider different invasion stages separately. On their own, these observations provide little predictive power for risk assessment, but when the causative mechanisms are understood (e.g. Phytophthora susceptibility) they provide valuable insights. As such there is considerable value in seeking the correlates and mechanisms underlying invasions for particular taxonomic or functional groups. PMID:24086442

  2. 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

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

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    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

  4. Greater sexual reproduction contributes to differences in demography of invasive plants and their noninvasive relatives.

    Science.gov (United States)

    Burns, Jean H; Pardini, Eleanor A; Schutzenhofer, Michele R; Chung, Y Anny; Seidler, Katie J; Knight, Tiffany M

    2013-05-01

    An understanding of the demographic processes contributing to invasions would improve our mechanistic understanding of the invasion process and improve the efficiency of prevention and control efforts. However, field comparisons of the demography of invasive and noninvasive species have not previously been conducted. We compared the in situ demography of 17 introduced plant species in St. Louis, Missouri, USA, to contrast the demographic patterns of invasive species with their less invasive relatives across a broad sample of angiosperms. Using herbarium records to estimate spread rates, we found higher maximum spread rates in the landscape for species classified a priori as invasive than for noninvasive introduced species, suggesting that expert classifications are an accurate reflection of invasion rate. Across 17 species, projected population growth was not significantly greater in invasive than in noninvasive introduced species. Among five taxonomic pairs of close relatives, however, four of the invasive species had higher projected population growth rates compared with their noninvasive relative. A Life Table Response Experiment suggested that the greater projected population growth rate of some invasive species relative to their noninvasive relatives was primarily a result of sexual reproduction. The greater sexual reproduction of invasive species is consistent with invaders having a life history strategy more reliant on fecundity than survival and is consistent with a large role of propagule pressure in invasion. Sexual reproduction is a key demographic correlate of invasiveness, suggesting that local processes influencing sexual reproduction, such as enemy escape, might be of general importance. However, the weak correlation of projected population growth with spread rates in the landscape suggests that regional processes, such as dispersal, may be equally important in determining invasion rate.

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

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    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

  6. Diet breadth influences how the impact of invasive plants is propagated through food webs.

    Science.gov (United States)

    Carvalheiro, Luisa G; Buckley, Yvonne M; Memmott, Jane

    2010-04-01

    Invasive plants are considered a major cause of ecosystem degradation worldwide. While their impacts on native plants have been widely reported, there is little information on how these impacts propagate through food webs and affect species at higher trophic levels. Using a quantitative food web approach we evaluated the impacts of an invasive plant on plant-herbivore-parasitoid communities, asking specifically how diet breadth influences the propagation of such impacts. Measuring the impact of the alien plant at the plant level seriously underestimated the community-level effect of this weed as it also caused changes in the abundance of native herbivores and parasitoids, along with a decrease in parasitoid species richness. The invading plant affected specialist and generalist subsets of communities differently, having significant and strong negative impacts on the abundance of all specialists with no negative effect on generalist consumers. Specialist consumer decline led to further disruptions of top-down regulatory mechanisms, releasing generalist species from competition via shared natural enemies. Plant invasion also significantly increased the evenness of species abundance of all trophic levels in the food webs, as well as the evenness of species interaction frequency. Extending impact evaluation to higher trophic levels and considering changes in trophic diversity within levels is hence essential for a full evaluation of the consequences of invasion by alien plants. Moreover, information on diet breadth of species in the invaded community should be taken into account when evaluating/predicting the impacts on any introduced species.

  7. 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

  8. Ecological Risk Assessment with MCDM of Some Invasive Alien Plants in China

    Science.gov (United States)

    Xie, Guowen; Chen, Weiguang; Lin, Meizhen; Zheng, Yanling; Guo, Peiguo; Zheng, Yisheng

    Alien plant invasion is an urgent global issue that threatens the sustainable development of the ecosystem health. The study of its ecological risk assessment (ERA) could help us to prevent and reduce the invasion risk more effectively. Based on the theory of ERA and methods of the analytic hierarchy process (AHP) of multi-criteria decision-making (MCDM), and through the analyses of the characteristics and processes of alien plant invasion, this paper discusses the methodologies of ERA of alien plant invasion. The assessment procedure consisted of risk source analysis, receptor analysis, exposure and hazard assessment, integral assessment, and countermeasure of risk management. The indicator system of risk source assessment as well as the indices and formulas applied to measure the ecological loss and risk were established, and the method for comprehensively assessing the ecological risk of alien plant invasion was worked out. The result of ecological risk analysis to 9 representative invasive alien plants in China shows that the ecological risk of Erigeron annuus, Ageratum conyzoides, Alternanthera philoxeroides and Mikania midrantha is high (grade1-2), that of Oxalis corymbosa and Wedelia chinensis comes next (grade3), while Mirabilis jalapa, Pilea microphylla and Calendula officinalis of the last (grade 4). Risk strategies are put forward on this basis.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. The role of the Forest Service in nonnative invasive plant research

    Science.gov (United States)

    Carolyn Hull Sieg; Julie S. Densow; Cynthia D. Huebner; James H. Miller

    2010-01-01

    In many of our Nation's wildlands, invasive nonnative plants contribute to the endangerment of native species and lead to other severe ecological and financial consequences. Projected trends of increasing human populations and associated development and globalization will contribute to increases in the already high rates of introductions of nonnative plant species...

  14. Inventory shows extent of non-native invasive plants in Minnesota forests

    Science.gov (United States)

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

    2009-01-01

    Readers are no doubt aware of the impact that non-native invasive plants (NNIP) present to Minnesota's ecosystems. The U.S. Forest Service's Northern Research Station (NRS) Forest Inventory and Analysis (FIA) Program is studying what determines where these plants are found, including forest type, tree density, disturbance, productivity, and topography.

  15. Invasive plant Alternanthera philoxeroides suffers more severe herbivory pressure than native competitors in recipient communities

    Science.gov (United States)

    Fan, Shufeng; Yu, Haihao; Dong, Xianru; Wang, Ligong; Chen, Xiuwen; Yu, Dan; Liu, Chunhua

    2016-01-01

    Host-enemy interactions are vital mechanisms that explain the success or failure of invasive plants in new ranges. We surveyed the defoliation of invasive Alternanthera philoxeroides and co-occurring native plants on two islands during different seasons over three consecutive years and measured the leaf nitrogen content and the C/N ratio of each plant species. To evaluate the effects of herbivory on A. philoxeroides, an herbivore exclosure experiment was conducted. We found that the mean defoliation of A. philoxeroides was higher than that of native plants, regardless of whether the dominant species was A. philoxeroides or native plants. A. philoxeroides defoliation increased significantly as the months progressed, whereas the defoliation of the total population of native plants was constant. The leaf nitrogen content was positively correlated with defoliation, and it was highest in A. philoxeroides. Additionally, A. philoxeroides in the herbivore exclusion treatment showed an increase in shoot biomass and total shoot length. Our study revealed that native generalist herbivores prefer the invasive plant to the natives because of the higher leaf nitrogen content. These results support the biotic resistance hypothesis, suggesting that native herbivore species can limit the population spread of invasive plants. PMID:27827418

  16. Chemical and structural effects of invasive plants on herbivore-parasitoid/predator interactions in native communities

    NARCIS (Netherlands)

    Harvey, J.A.; Fortuna, T.

    2012-01-01

    The introduction and/or spread of exotic organisms into new habitats is considered a major threat to biodiversity. Invasive plants have been shown to negatively affect native communities, competing with and excluding other plants and disrupting a wide range of trophic interactions associated with

  17. Pathways of invasive plant spread to Alaska: III. contaminants in crop and grass seed

    Science.gov (United States)

    Invasive plants disperse to new areas via numerous pathways. Study of these pathways helps to focus limited budgets for prevention and early detection. This study examined seed contaminants in imported crop and grass seed as pathway for plant dispersal to Alaska. Crop and grass seed were purchased f...

  18. 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.

  19. Adaptive management in EBIPM: A key to success in invasive plant management

    Science.gov (United States)

    EBIPM is an important advancement in management of invasive plants. EBIPM puts land management decisions on a sound-footing based on ecological principles that cause plant community change. These principles, however, must be incorporated into the adaptive management cycle to truly make a change in h...

  20. Nonnative invasive plants of Pacific coast forests: a field guide for identification

    Science.gov (United States)

    Andrew N. Gray; Katie Barndt; Sarah H. Reichard

    2011-01-01

    Nonnative plants affect the composition and function of natural and managed ecosystems and have large economic effects through lost or degraded land use and eradication costs. In spite of their importance, very little comprehensive information on the abundance, distribution, and impact of nonnative invasive plants is available. The objective of this study was to...

  1. Effects of Invasive-Plant Management on Nitrogen-Removal Services in Freshwater Tidal Marshes

    OpenAIRE

    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 eco...

  2. 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.

  3. 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 ...

  4. 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...

  5. Differential plant invasiveness is not always driven by host promiscuity with bacterial symbionts.

    Science.gov (United States)

    Klock, Metha M; Barrett, Luke G; Thrall, Peter H; Harms, Kyle E

    2016-01-01

    Identification of mechanisms that allow some species to outcompete others is a fundamental goal in ecology and invasive species management. One useful approach is to examine congeners varying in invasiveness in a comparative framework across native and invaded ranges. Acacia species have been widely introduced outside their native range of Australia, and a subset of these species have become invasive in multiple parts of the world. Within specific regions, the invasive status of these species varies. Our study examined whether a key mechanism in the life history of Acacia species, the legume-rhizobia symbiosis, influences acacia invasiveness on a regional scale. To assess the extent to which species varying in invasiveness correspondingly differ with regard to the diversity of rhizobia they associate with, we grew seven Acacia species ranging in invasiveness in California in multiple soils from both their native (Australia) and introduced (California) ranges. In particular, the aim was to determine whether more invasive species formed symbioses with a wider diversity of rhizobial strains (i.e. are more promiscuous hosts). We measured and compared plant performance, including aboveground biomass, survival, and nodulation response, as well as rhizobial community composition and richness. Host promiscuity did not differ among invasiveness categories. Acacia species that varied in invasiveness differed in aboveground biomass for only one soil and did not differ in survival or nodulation within individual soils. In addition, acacias did not differ in rhizobial richness among invasiveness categories. However, nodulation differed between regions and was generally higher in the native than introduced range. Our results suggest that all Acacia species introduced to California are promiscuous hosts and that host promiscuity per se does not explain the observed differences in invasiveness within this region. Our study also highlights the utility of assessing potential

  6. Plant invasions, generalist herbivores, and novel defense weapons

    Science.gov (United States)

    Urs Schaffner; Wendy M. Ridenour; Vera C. Wolf; Thomas Bassett; Caroline Muller; Heinz Muller-Scharer; Steve Sutherland; Christopher J. Lortie; Ragan M. Callaway

    2011-01-01

    One commonly accepted mechanism for biological invasions is that species, after introduction to a new region, leave behind their natural enemies and therefore increase in distribution and abundance. However, which enemies are escaped remains unclear. Escape from specialist invertebrate herbivores has been examined in detail, but despite the profound effects of...

  7. 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

  8. Learning from our mistakes: minimizing problems with invasive biofuel plants

    CSIR Research Space (South Africa)

    Richardson, DM

    2011-03-01

    Full Text Available . Economic driving forces are crucial. Important lessons to be learnt from forestry for reducing problems with invasiveness of alien species for biofuel production include: the use of global databases and screening tools for identifying high-risk species...

  9. The Haustorium, a Specialized Invasive Organ in Parasitic Plants.

    Science.gov (United States)

    Yoshida, Satoko; Cui, Songkui; Ichihashi, Yasunori; Shirasu, Ken

    2016-04-29

    Parasitic plants thrive by infecting other plants. Flowering plants evolved parasitism independently at least 12 times, in all cases developing a unique multicellular organ called the haustorium that forms upon detection of haustorium-inducing factors derived from the host plant. This organ penetrates into the host stem or root and connects to its vasculature, allowing exchange of materials such as water, nutrients, proteins, nucleotides, pathogens, and retrotransposons between the host and the parasite. In this review, we focus on the formation and function of the haustorium in parasitic plants, with a specific emphasis on recent advances in molecular studies of root parasites in the Orobanchaceae and stem parasites in the Convolvulaceae.

  10. Modeling population dynamics, landscape structure, and management decisions for controlling the spread of invasive plants.

    Science.gov (United States)

    Caplat, Paul; Coutts, Shaun; Buckley, Yvonne M

    2012-02-01

    Invasive plants cause substantial economic and environmental damage throughout the world. However, eradication of most invasive species is impossible and, in some cases, undesirable. An alternative is to slow the spread of an invasive species, which can delay impacts or reduce their extent. We identify three main areas where models are used extensively in the study of plant spread and its management: (i) identifying the key drivers of spread to better target management, (ii) determining the role spatial structure of landscapes plays in plant invasions, and (iii) integrating management structures and limitations to guide the implementation of control measures. We show how these three components have been approached in the ecological literature as well as their potential for improving management practices. Particularly, we argue that scientists can help managers of invasive species by providing information about plant invasion on which managers can base their decisions (i and ii) and by modeling the decision process through optimization and agent-based models (iii). Finally, we show how these approaches can be articulated for integrative studies. © 2012 New York Academy of Sciences.

  11. Explaining naturalization and invasiveness: new insights from historical ornamental plant catalogs.

    Science.gov (United States)

    Lavoie, Claude; Joly, Simon; Bergeron, Alexandre; Guay, Geneviève; Groeneveld, Elisabeth

    2016-10-01

    We identified plant attributes associated with naturalization and invasiveness using century-old ornamental plant catalogs from Québec (Canada). We tested the hypothesis that naturalization is determined by fewer factors than invasiveness, as the latter also requires dispersal, which introduces additional complexity. The approach we used took into account not only plant attributes as explanatory factors, but also propagule pressure, while accounting for phylogenetic relationships among species. Museum collections were used, in combination with scientific journal databases, to assess invasiveness. Particular attention was given to species that never escaped from gardens and thus represent cases of "failed" invasions. Naturalization in cold-temperate environments is determined by fewer factors than invasion, but only if phylogenetic links between species are taken into account, highlighting the importance of phylogenetic tools for analyzing species pools not resulting from a random selection of taxa. Hardiness is the main factor explaining naturalization in Québec. Invasion requires dispersal, as shown by three significant variables associated with the spread of diaspores in the invasiveness model (seed weight, hydrochory, number of seed dispersal modes). Plants that are not cold-hardy are likely to disappear from the market or nature, but the disappearance phenomenon is more complex, involving also seed dispersal abilities and propagule pressure. Factors contributing to naturalization or invasiveness may differ greatly between regions. Differences are due in part to the plant traits used in the models and the methodology. However, this study, conducted in a cold-temperate region, sheds new light on what is likely a context (climatic)-dependant phenomenon.

  12. 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.

  13. Climate change both facilitates and inhibits invasive plant ranges in New England.

    Science.gov (United States)

    Merow, Cory; Bois, Sarah Treanor; Allen, Jenica M; Xie, Yingying; Silander, John A

    2017-04-18

    Forecasting ecological responses to climate change, invasion, and their interaction must rely on understanding underlying mechanisms. However, such forecasts require extrapolation into new locations and environments. We linked demography and environment using experimental biogeography to forecast invasive and native species' potential ranges under present and future climate in New England, United States to overcome issues of extrapolation in novel environments. We studied two potentially nonequilibrium invasive plants' distributions, Alliaria petiolata (garlic mustard) and Berberis thunbergii (Japanese barberry), each paired with their native ecological analogs to better understand demographic drivers of invasions. Our models predict that climate change will considerably reduce establishment of a currently prolific invader ( A. petiolata ) throughout New England driven by poor demographic performance in warmer climates. In contrast, invasion of B. thunbergii will be facilitated because of higher growth and germination in warmer climates, with higher likelihood to establish farther north and in closed canopy habitats in the south. Invasion success is in high fecundity for both invasive species and demographic compensation for A petiolata relative to native analogs. For A. petiolata , simulations suggest that eradication efforts would require unrealistic efficiency; hence, management should focus on inhibiting spread into colder, currently unoccupied areas, understanding source-sink dynamics, and understanding community dynamics should A. petiolata (which is allelopathic) decline. Our results-based on considerable differences with correlative occurrence models typically used for such biogeographic forecasts-suggest the urgency of incorporating mechanism into range forecasting and invasion management to understand how climate change may alter current invasion patterns.

  14. 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

  15. Different Responses of an Invasive Clonal Plant Wedelia trilobata and its Native Congener to Gibberellin: Implications for Biological Invasion.

    Science.gov (United States)

    Dai, Zhi-Cong; Fu, Wei; Qi, Shan-Shan; Zhai, De-Li; Chen, Si-Chong; Wan, Ling-Yun; Huang, Ping; Du, Dao-Lin

    2016-02-01

    The invasive clonal plant Wedelia trilobata contains higher levels of ent-kaurane diterpenes, which are precursors of gibberellins (GAs), and higher rates of clonal growth than its native congener W. chinensis in invaded habitats. We hypothesized that the higher levels of endogenous GAs facilitate greater ramet growth in W. trilobata compared with W. chinensis. We quantified endogenous levels of GA1+3 in the two species and compared their growth responses to the changes of endogenous and exogenous GA3 by using short-term and long-term hydroponics experiments. After a period of homogeneous cultivation, levels of endogenous GA1+3 were higher in W. trilobata than in W. chinensis. The reduction of endogenous GAs repressed the emergence of adventitious roots and the growth of W. trilobata in the initial cultivation stage, and inhibited its shoot elongation and biomass. Levels of endogenous GA1+3 were positively correlated with the length of shoots and adventitious roots of W. trilobata. Adventitious roots of W. trilobata also emerged earlier and grew faster when treated with exogenous GA3. In contrast, exogenous GA3 treatment inhibited the length of adventitious roots in W. chinensis, and levels of endogenous GA1+3 did not correlate with shoot or adventitious root length. Our study suggests that GAs accelerate the rapid clonal growth of W. trilobata, more than that of its native congener W. chinensis, illustrating the relationship between plant hormones and the clonal growth of invasive plants. These findings are important for understanding the mechanisms associated with the invasiveness of clonal plants and their potential management.

  16. 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.

  17. 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.

  18. 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...

  19. 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 ...

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

    OpenAIRE

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

    2016-01-01

    Background: 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 invasi...

  1. Shifting global invasive potential of European plants with climate change

    OpenAIRE

    Peterson, A.T.; Stewart, Aimee; Mohamed, Kamal I.; Araújo, Miguel B.

    2008-01-01

    Global climate change and invasions by nonnative species rank among the top concerns for agents of biological loss in coming decades. Although each of these themes has seen considerable attention in the modeling and forecasting communities, their joint effects remain little explored and poorly understood. We developed ecological niche models for 1804 species from the European flora, which we projected globally to identify areas of potential distribution, both at present and across 4 scenarios...

  2. 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

  3. 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...

  4. 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)

  5. Habitat fragmentation, tree diversity, and plant invasion interact to structure forest caterpillar communities.

    Science.gov (United States)

    Stireman, John O; Devlin, Hilary; Doyle, Annie L

    2014-09-01

    Habitat fragmentation and invasive species are two of the most prominent threats to terrestrial ecosystems. Few studies have examined how these factors interact to influence the diversity of natural communities, particularly primary consumers. Here, we examined the effects of forest fragmentation and invasion of exotic honeysuckle (Lonicera maackii, Caprifoliaceae) on the abundance and diversity of the dominant forest herbivores: woody plant-feeding Lepidoptera. We systematically surveyed understory caterpillars along transects in 19 forest fragments over multiple years in southwestern Ohio and evaluated how fragment area, isolation, tree diversity, invasion by honeysuckle and interactions among these factors influence species richness, diversity and abundance. We found strong seasonal variation in caterpillar communities, which responded differently to fragmentation and invasion. Abundance and richness increased with fragment area, but these effects were mitigated by high levels of honeysuckle, tree diversity, landscape forest cover, and large recent changes in area. Honeysuckle infestation was generally associated with decreased caterpillar abundance and diversity, but these effects were strongly dependent on other fragment traits. Effects of honeysuckle on abundance were moderated when fragment area, landscape forest cover and tree diversity were high. In contrast, negative effects of honeysuckle invasion on caterpillar diversity were most pronounced in fragments with high tree diversity and large recent increases in area. Our results illustrate the complex interdependencies of habitat fragmentation, plant diversity and plant invasion in their effects on primary consumers and emphasize the need to consider these processes in concert to understand the consequences of anthropogenic habitat change for biodiversity.

  6. Effects of white-tailed deer and invasive plants on the herb layer of suburban forests.

    Science.gov (United States)

    Morrison, Janet A

    2017-11-01

    Lack of hunting and predators and proximity to human communities make suburban forests prone to high deer abundance and non-native plant invasions. I investigated these likely drivers of community structure in the herb layers of six suburban forests in one region of New Jersey, USA. In 223 plots I assessed the herb layer response to 2.5 years with or without deer fencing and the early stage of invasion from seed additions of Microstegium vimineum , an invasive, annual grass. Non-native plants and herbaceous native plants were affected very little by fencing or M. vimineum invasion. In contrast, across all forests the combination of deer access and M. vimineum addition had a strongly negative effect on woody native percent cover. Forests differed in overall fencing effects on woody natives; their cover was greater in fenced plots in just three forests, suggesting greater deer pressure in those forests during the experiment. The early invasion by M. vimineum was greatest in two of these same forests, but was not influenced by fencing. Multi-group structural equation modelling compared two groups of forests that differed in vegetation abundance and other characteristics. It paralleled the results above and also showed no negative influence of non-native cover on native cover, even in the forests where non-native cover was greater. It identified a positive effect of light level on herb layer plants in the forests with less vegetation, and also revealed a positive effect of soil water potential (SWP) on non-native plants in the forests with more vegetation, which had higher SWP. These suburban forests within a common region varied widely in native and non-native herb layer abundance, the early success of M. vimineum invasion and the herb layer's response to early invasion and protection from deer.

  7. 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.

  8. 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

  9. Negative per capita effects of two invasive plants, Lythrum salicaria and Phalaris arundinacea, on the moth diversity of wetland communities.

    Science.gov (United States)

    Schooler, S S; McEvoy, P B; Hammond, P; Coombs, E M

    2009-06-01

    Invasive plants have been shown to negatively affect the diversity of plant communities. However, little is known about the effect of invasive plants on the diversity at other trophic levels. In this study, we examine the per capita effects of two invasive plants, purple loosestrife (Lythrum salicaria) and reed canary grass (Phalaris arundinacea), on moth diversity in wetland communities at 20 sites in the Pacific Northwest, USA. Prior studies document that increasing abundance of these two plant species decreases the diversity of plant communities. We predicted that this reduction in plant diversity would result in reduced herbivore diversity. Four measurements were used to quantify diversity: species richness (S), community evenness (J), Brillouin's index (H) and Simpson's index (D). We identified 162 plant species and 156 moth species across the 20 wetland sites. The number of moth species was positively correlated with the number of plant species. In addition, invasive plant abundance was negatively correlated with species richness of the moth community (linear relationship), and the effect was similar for both invasive plant species. However, no relationship was found between invasive plant abundance and the three other measures of moth diversity (J, H, D) which included moth abundance in their calculation. We conclude that species richness within, and among, trophic levels is adversely affected by these two invasive wetland plant species.

  10. Crabs mediate interactions between native and invasive salt marsh plants: a mesocosm study.

    Science.gov (United States)

    Zhang, Xiao-Dong; Jia, Xin; Chen, Yang-Yun; Shao, Jun-Jiong; Wu, Xin-Ru; Shang, Lei; Li, Bo

    2013-01-01

    Soil disturbance has been widely recognized as an important factor influencing the structure and dynamics of plant communities. Although soil reworkers were shown to increase habitat complexity and raise the risk of plant invasion, their role in regulating the interactions between native and invasive species remains unclear. We proposed that crab activities, via improving soil nitrogen availability, may indirectly affect the interactions between invasive Spartina alterniflora and native Phragmites australis and Scirpus mariqueter in salt marsh ecosystems. We conducted a two-year mesocosm experiment consisting of five species combinations, i.e., monocultures of three species and pair-wise mixtures of invasive and native species, with crabs being either present or absent for each combination. We found that crabs could mitigate soil nitrogen depletion in the mesocosm over the two years. Plant performance of all species, at both the ramet-level (height and biomass per ramet) and plot-level (density, total above- and belowground biomass), were promoted by crab activities. These plants responded to crab disturbance primarily by clonal propagation, as plot-level performance was more sensitive to crabs than ramet-level. Moreover, crab activities altered the competition between Spartina and native plants in favor of the former, since Spartina was more promoted than native plants by crab activities. Our results suggested that crab activities may increase the competition ability of Spartina over native Phragmites and Scirpus through alleviating soil nitrogen limitation.

  11. Crabs mediate interactions between native and invasive salt marsh plants: a mesocosm study.

    Directory of Open Access Journals (Sweden)

    Xiao-Dong Zhang

    Full Text Available Soil disturbance has been widely recognized as an important factor influencing the structure and dynamics of plant communities. Although soil reworkers were shown to increase habitat complexity and raise the risk of plant invasion, their role in regulating the interactions between native and invasive species remains unclear. We proposed that crab activities, via improving soil nitrogen availability, may indirectly affect the interactions between invasive Spartina alterniflora and native Phragmites australis and Scirpus mariqueter in salt marsh ecosystems. We conducted a two-year mesocosm experiment consisting of five species combinations, i.e., monocultures of three species and pair-wise mixtures of invasive and native species, with crabs being either present or absent for each combination. We found that crabs could mitigate soil nitrogen depletion in the mesocosm over the two years. Plant performance of all species, at both the ramet-level (height and biomass per ramet and plot-level (density, total above- and belowground biomass, were promoted by crab activities. These plants responded to crab disturbance primarily by clonal propagation, as plot-level performance was more sensitive to crabs than ramet-level. Moreover, crab activities altered the competition between Spartina and native plants in favor of the former, since Spartina was more promoted than native plants by crab activities. Our results suggested that crab activities may increase the competition ability of Spartina over native Phragmites and Scirpus through alleviating soil nitrogen limitation.

  12. 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: L as Lagiewnicki a nd P olesie 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)

  13. 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

  14. 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.

  15. Strong human association with plant invasion success for Trifolium introductions to New Zealand.

    Science.gov (United States)

    Gravuer, Kelly; Sullivan, Jon J; Williams, Peter A; Duncan, Richard P

    2008-04-29

    It has proven difficult, when focused only on biological determinants, to explain why some plant species become naturalized in or invade new locations, whereas others fail. We analyzed the invasion of Trifolium (true clover) species into New Zealand, assessing a range of human, biogeographic, and biological influences at three key invasion stages: introduction, naturalization, and spread. We used sparse principal component analysis (SPCA) to define suites of related attributes and aggregated boosted trees to model relationships with invasion outcomes. Human and biogeographic attributes were strongly associated with success at all stages. Whereas biogeographic attributes, notably large native range, were consistently associated with success, different human factors appeared to favor success at different stages, such as presence in early trade/immigration hotspots (introduction), intentional large-scale planting (naturalization), and frequent presence as a seed contaminant (relative spread rate). Biological traits were less strongly associated with success for introduction and spread and little if at all for naturalization; we found that tall perennials with long flowering periods were more frequently selected for introduction, whereas species with extended flowering in New Zealand spread more rapidly. In addition to causal relationships, the importance of human factors may reflect indirect associations, including ecological traits associated with both human use and invasion. Nevertheless, our results highlight key roles that humans can play in facilitating plant invasion via two pathways: (i) commercial introduction leading to widespread planting and concomitant naturalization and spread and (ii) unintentional introduction and spread of species associated with human activities, such as seed contaminants.

  16. 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 habitat suitability models can be highly useful tools for guiding invasive species monitoring

  17. 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

  18. 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

  19. 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.......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....

  20. 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.

  1. 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...

  2. 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.

  3. 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.

  4. [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.

  5. Emerging technologies for non-invasive quantification of physiological oxygen transport in plants.

    Science.gov (United States)

    Chaturvedi, P; Taguchi, M; Burrs, S L; Hauser, B A; Salim, W W A W; Claussen, J C; McLamore, E S

    2013-09-01

    Oxygen plays a critical role in plant metabolism, stress response/signaling, and adaptation to environmental changes (Lambers and Colmer, Plant Soil 274:7-15, 2005; Pitzschke et al., Antioxid Redox Signal 8:1757-1764, 2006; Van Breusegem et al., Plant Sci 161:405-414, 2001). Reactive oxygen species (ROS), by-products of various metabolic pathways in which oxygen is a key molecule, are produced during adaptation responses to environmental stress. While much is known about plant adaptation to stress (e.g., detoxifying enzymes, antioxidant production), the link between ROS metabolism, O2 transport, and stress response mechanisms is unknown. Thus, non-invasive technologies for measuring O2 are critical for understanding the link between physiological O2 transport and ROS signaling. New non-invasive technologies allow real-time measurement of O2 at the single cell and even organelle levels. This review briefly summarizes currently available (i.e., mainstream) technologies for measuring O2 and then introduces emerging technologies for measuring O2. Advanced techniques that provide the ability to non-invasively (i.e., non-destructively) measure O2 are highlighted. In the near future, these non-invasive sensors will facilitate novel experimentation that will allow plant physiologists to ask new hypothesis-driven research questions aimed at improving our understanding of physiological O2 transport.

  6. 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.

  7. 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.

  8. 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…

  9. Simulated acid rain alters litter decomposition and enhances the allelopathic potential of the invasive plant Wedelia trilobata (Creeping Daisy)

    Science.gov (United States)

    Invasive species and acid rain cause global environmental problems. Limited information exists, however, concerning the effects of acid rain on the invasiveness of these plants. For example, creeping daisy, an invasive exotic allelopathic weed, has caused great damage in southern China where acid ra...

  10. Using long-term datasets to study exotic plant invasions on rangelands in the western United States

    Science.gov (United States)

    C. Morris; L. R. Morris; A. J. Leffler; C. D. Holifield Collins; A. D. Forman; M. A. Weltz; S. G. Kitchen

    2013-01-01

    Invasions by exotic species are generally described using 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 is to compare invasion curves at the local scale to the logistic growth...

  11. 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.

  12. Will climate change increase the risk of plant invasions into mountains?

    Science.gov (United States)

    Petitpierre, Blaise; McDougall, Keith; Seipel, Tim; Broennimann, Olivier; Guisan, Antoine; Kueffer, Christoph

    2016-03-01

    Mountain ecosystems have been less adversely affected by invasions of non-native plants than most other ecosystems, partially because most invasive plants in the lowlands are limited by climate and cannot grow under harsher high-elevation conditions. However, with ongoing climate change, invasive species may rapidly move upwards and threaten mid-, and then high-elevation mountain ecosystems. We evaluated this threat by modeling the current and future habitat suitability for 48 invasive plant species in Switzerland and New South Wales, Australia. Both regions had contrasting climate interactions with elevation, resulting in possible different responses of species distributions to climate change. Using a species distribution modeling approach that combines data from two spatial scales, we built high-resolution species distribution models (≤ 250 m) that account for the global climatic niche of species and also finer variables depicting local climate and disturbances. We found that different environmental drivers limit the elevation range of invasive species in each of the two regions, leading to region-specific species responses to climate change. The optimal suitability for plant invaders is predicted to markedly shift from the lowland to the montane or subalpine zone in Switzerland, whereas the upward shift is far less pronounced in New South Wales where montane and subalpine elevations are already suitable. The results suggest that species most likely to invade high elevations in Switzerland will be cold-tolerant, whereas species with an affinity to moist soils are most likely to invade higher elevations in Australia. Other plant traits were only marginally associated with elevation limits. These results demonstrate that a more systematic consideration of future distributions of invasive species is required in conservation plans of not yet invaded mountainous ecosystems.

  13. Parallel evolution in an invasive plant species: evolutionary changes in allocation to growth, defense, competitive ability and regrowth of invasive Jacobaea vulgaris

    OpenAIRE

    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, the release from specialist herbivores after introduction is expected invasive plants to shift their costly defense against specialist herbivores to cheaper defense against local generalist herbivore...

  14. 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...

  15. 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...

  16. 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

  17. Plant selection and grazing activity of the invasive snail Theba ...

    African Journals Online (AJOL)

    The land snail Theba pisana is a coastal species native to the Mediterranean but has been introduced to regions all over the world, including South Africa and Australia, where it is considered a pest. This study examines the diet of T. pisana and its preference for certain dune plants in the Cape Recife Nature Reserve of ...

  18. Research on invasive-plant traits tells us a lot

    Czech Academy of Sciences Publication Activity Database

    van Kleunen, M.; Dawson, W.; Dostál, Petr

    2011-01-01

    Roč. 26, č. 7 (2011), s. 317-317 ISSN 0169-5347 Institutional research plan: CEZ:AV0Z60050516 Keywords : global changes * habitat productivity * native and non-native plant species Subject RIV: EF - Botanics Impact factor: 15.748, year: 2011

  19. Invasive alien plant species dynamics in the Himalayan region under climate change.

    Science.gov (United States)

    Lamsal, Pramod; Kumar, Lalit; Aryal, Achyut; Atreya, Kishor

    2018-01-25

    Climate change will impact the dynamics of invasive alien plant species (IAPS). However, the ability of IAPS under changing climate to invade mountain ecosystems, particularly the Himalayan region, is less known. This study investigates the current and future habitat of five IAPS of the Himalayan region using MaxEnt and two representative concentration pathways (RCPs). Two invasive species, Ageratum conyzoides and Parthenium hysterophorus, will lose overall suitable area by 2070, while Ageratina adenophora, Chromolaena odorata and Lantana camara will gain suitable areas and all of them will retain most of the current habitat as stable. The southern Himalayan foothills will mostly conserve species ecological niches, while suitability of all the five species will decrease with increasing elevation. Such invasion dynamics in the Himalayan region could have impacts on numerous ecosystems and their biota, ecosystem services and human well-being. Trans-boundary response strategies suitable to the local context of the region could buffer some of the likely invasion impacts.

  20. Modeling the Impact of Spatial Structure on Growth Dynamics of Invasive Plant Species

    Science.gov (United States)

    Murphy, James T.; Johnson, Mark P.; Walshe, Ray

    2013-07-01

    Invasive nonindigenous plant species can have potentially serious detrimental effects on local ecosystems and, as a result, costly control efforts often have to be put in place to protect habitats. An example of an invasive problem on a global scale involves the salt marsh grass species from the genus Spartina. The spread of Spartina anglica in Europe and Asia has drawn much concern due to its ability to convert coastal habitats into cord-grass monocultures and to alter the native food webs. However, the patterns of invasion of Spartina species are amenable to spatially-explicit modeling strategies that take into account both temporal and spatio-temporal processes. In this study, an agent-based model of Spartina growth on a simulated mud flat environment was developed in order to study the effects of spatial pattern and initial seedling placement on the invasion dynamics of the population. The spatial pattern of an invasion plays a key role in the rate of spread of the species and understanding this can lead to significant cost savings when designing efficient control strategies. We present here a model framework that can be used to explicitly represent complex spatial and temporal patterns of invasion in order to be able to predict quantitatively the impact of these factors on invasion dynamics. This would be a useful tool for assessing eradication strategies and choosing optimal control solutions in order to be able to minimize future control costs.

  1. Effects of chemical management for invasive plants on the performance of Lithobates pipiens tadpoles.

    Science.gov (United States)

    Curtis, Amanda N; Bidart, M Gabriela

    2017-11-01

    Invasive plants impact amphibians by altering habitat, altering species interactions, and releasing potentially toxic secondary chemicals. Despite being costly and having the potential to affect nontarget wildlife, chemical management is commonly used to control invasive plants. Prior research has indicated that individual effects of invasive plants or herbicides can be harmful to aquatic organisms; however, information is lacking on the combined effect of these factors on amphibians. A laboratory experiment was performed to assess the impact of leachates of the invasive plants Eurasian watermilfoil (Myriophyllum spicatum) and European buckthorn (Rhamnus cathartica), the herbicide Renovate ® 3 (triclopyr [3, 5, 6-trichloro-2-pyridinyloxyacetic acid]), and the combined effects of each plant leachate and the herbicide on the growth, morphology, and survival of northern leopard frog (Lithobates pipiens) tadpoles. No effects of treatment on survival were observed. Tadpole exposure to M. spicatum reduced body mass by 17%, exposure to R. cathartica increased body mass by 36%, and exposure to R. cathartica + low herbicide increased body mass by 38% (although only early in the experiment). Exposure to Renovate 3 induced a 16% and 29% decrease in tadpole size in lower (0.22 mg triclopyr active ingredient [a.i.]/L) and higher (0.92 mg triclopyr a.i./L) concentration treatments, respectively. Results from the present study highlight the importance of considering both individual and combined effects of invasive plants and herbicides because they may have different outcomes for tadpole growth and development. Environ Toxicol Chem 2017;36:2958-2964. © 2017 SETAC. © 2017 SETAC.

  2. Connecting differential responses of native and invasive riparian plants to climate change and environmental alteration.

    Science.gov (United States)

    Flanagan, Neal E; Richardson, Curtis J; Ho, Mengchi

    2015-04-01

    Climate change is predicted to impact river systems in the southeastern United States through alterations of temperature, patterns of precipitation and hydrology. Future climate scenarios for the southeastern United States predict (1) surface water temperatures will warm in concert with air temperature, (2) storm flows will increase and base flows will decrease, and (3) the annual pattern of synchronization between hydroperiod and water temperature will be altered. These alterations are expected to disturb floodplain plant communities, making them more vulnerable to establishment of invasive species. The primary objective of this study is to evaluate whether native and invasive riparian plant assemblages respond differently to alterations of climate and land use. To study the response of riparian wetlands to watershed and climate alterations, we utilized an existing natural experiment imbedded in gradients of temperature and hydrology-found among dammed and undammed rivers. We evaluated a suite of environmental variables related to water temperature, hydrology, watershed disturbance, and edaphic conditions to identify the strongest predictors of native and invasive species abundances. We found that native species abundance is strongly influenced by climate-driven variables such as temperature and hydrology, while invasive species abundance is more strongly influenced by site-specific factors such as land use and soil nutrient availability. The patterns of synchronization between plant phenology, annual hydrographs, and annual water temperature cycles may be key factors sustaining the viability of native riparian plant communities. Our results demonstrate the need to understand the interactions between climate, land use, and nutrient management in maintaining the species diversity of riparian plant communities. Future climate change is likely to result in diminished competitiveness of native plant species, while the competitiveness of invasive species will increase

  3. Archaea and bacteria mediate the effects of native species root loss on fungi during plant invasion.

    Science.gov (United States)

    Mamet, Steven D; Lamb, Eric G; Piper, Candace L; Winsley, Tristrom; Siciliano, Steven D

    2017-05-01

    Although invasive plants can drive ecosystem change, little is known about the directional nature of belowground interactions between invasive plants, native roots, bacteria, archaea and fungi. We used detailed bioinformatics and a recently developed root assay on soils collected in fescue grassland along a gradient of smooth brome (Bromus inermis Leyss) invasion to examine the links between smooth brome shoot litter and root, archaea, bacteria and fungal communities. We examined (1) aboveground versus belowground influences of smooth brome on soil microbial communities, (2) the importance of direct versus microbe-mediated impacts of plants on soil fungal communities, and (3) the web of roots, shoots, archaea, bacteria and fungi interactions across the A and B soil horizons in invaded and non-invaded sites. Archaea and bacteria influenced fungal composition, but not vice versa, as indicated by redundancy analyses. Co-inertia analyses suggested that bacterial-fungal variance was driven primarily by 12 bacterial operational taxonomic units (OTUs). Brome increased bacterial diversity via smooth brome litter in the A horizon and roots in the B horizon, which then reduced fungal diversity. Archaea increased abundance of several bacterial OTUs, and the key bacterial OTUs mediated changes in the fungi's response to invasion. Overall, native root diversity loss and bacterial mediation were more important drivers of fungal composition than were the direct effects of increases in smooth brome. Critically, native plant species displacement and root loss appeared to be the most important driver of fungal composition during invasion. This causal web likely gives rise to the plant-fungi feedbacks, which are an essential factor determining plant diversity in invaded grassland ecosystems.

  4. 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

  5. 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

    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...... range of habitats in introduced areas by phenotypic plasticity rather than local adaptation. © 2010 The Author. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved....

  6. A Bioeconomic Model of Cattle Stocking on Rangeland Threatened by Invasive Plants and Nitrogen Deposition

    OpenAIRE

    David Finnoff; Aaron Strong; John Tschirhart

    2008-01-01

    Across western North America, invasive plant species and elevated levels of nitrogen are threatening the productivity of rangelands. A bioeconomic model of stocking cattle on these rangelands is used to show that optimal stocking depends on the competition between native grasses and the invaders. However, nitrogen deposition is important in determining the ultimate rangeland species composition. Endogenous changes in plant successional thresholds are due to the interplay of nitrogen depositio...

  7. A Manual for the Identification of Invasive Plants in Southern Forests

    Science.gov (United States)

    Lewis Zimmerman

    2012-01-01

    This manual was created specifically for use by the U.S. Forest Service Southern Research Station (SRS), Forest Inventory and Analysis (FIA) field survey crews. The SRS FIA unit currently collects data on 33 invasive plants or groups across 13 States. The ability to accurately identify plant species in the field is a crucial component of monitoring a species’ presence...

  8. Climate and Human Pressure Constraints Co-Explain Regional Plant Invasion at Different Spatial Scales.

    Science.gov (United States)

    Campos, Juan Antonio; García-Baquero, Gonzalo; Caño, Lidia; Biurrun, Idoia; García-Mijangos, Itziar; Loidi, Javier; Herrera, Mercedes

    2016-01-01

    Alien species invasion represents a global threat to biodiversity and ecosystems. Explaining invasion patterns in terms of environmental constraints will help us to assess invasion risks and plan control strategies. We aim to identify plant invasion patterns in the Basque Country (Spain), and to determine the effects of climate and human pressure on that pattern. We modeled the regional distribution of 89 invasive plant species using two approaches. First, distance-based Moran's eigenvector maps were used to partition variation in the invasive species richness, S, into spatial components at broad and fine scales; redundancy analysis was then used to explain those components on the basis of climate and human pressure descriptors. Second, we used generalized additive mixed modeling to fit species-specific responses to the same descriptors. Climate and human pressure descriptors have different effects on S at different spatial scales. Broad-scale spatially structured temperature and precipitation, and fine-scale spatially structured human population density and percentage of natural and semi-natural areas, explained altogether 38.7% of the total variance. The distribution of 84% of the individually tested species was related to either temperature, precipitation or both, and 68% was related to either population density or natural and semi-natural areas, displaying similar responses. The spatial pattern of the invasive species richness is strongly environmentally forced, mainly by climate factors. Since individual species responses were proved to be both similarly constrained in shape and explained variance by the same environmental factors, we conclude that the pattern of invasive species richness results from individual species' environmental preferences.

  9. 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.

  10. 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

  11. 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....

  12. 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 ...

  13. 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

  14. 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

  15. Management and control methods of invasive alien freshwater aquatic plants: a review

    NARCIS (Netherlands)

    Hussner, Andreas; Stiers, I.; Verhofstad, M.J.J.M.; Bakker, E.S.; Grutters, B.M.C.; Haury, J.; van Valkenburg, J.L.C.H.; Brundu, G.; Newman, J.; Clayton, J.S.; Anderson, L.W.J.; Hofstra, D.

    2017-01-01

    Introduced invasive alien aquatic plants (IAAPs) threaten ecosystems due to their excessive growth and have both ecological and economic impacts. To minimize these impacts, effective management of IAAPs is required according to national or international laws and regulations (e.g. the new EU

  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. Impacts of invasive plants on songbirds: Using song structure as an indicator of habitat quality

    Science.gov (United States)

    Yvette Ortega

    2007-01-01

    Invasive species can alter habitat quality over broad scales, so they pose a severe threat to songbird populations. Through our long-term research program supported by BEMRP, we have found that changes in habitat quality induced by exotic plants like spotted knapweed can lead to subtle yet profound changes in songbird populations. For example, in knapweed-invaded...

  18. Plant traits and spread of the invasive salt marsh grass, Spartina ...

    African Journals Online (AJOL)

    Spartina alterniflora Loisel., widely recognised as an aggressive invader of estuaries and salt marshes around the world, was discovered growing in the temporarily open/closed Great Brak Estuary on the southern Cape coast of South Africa in 2004. This is the first record of this invasive plant in Africa as well as its first ...

  19. The extent of selected nonnative invasive plants on southern forest lands

    Science.gov (United States)

    Sonja N. Oswalt; Christopher M. Oswalt

    2011-01-01

    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...

  20. ARE INVASIVE RIPARIAN PLANTS ASSOCIATED WITH REDUCED BIOTIC CONDITION OF FAUNA IN WESTERN US STREAMS?

    Science.gov (United States)

    Yes. Records on the presence or absence of 12 invasive riparian plant taxa and observations on macroinvertebrate and vertebrate communities within streams were collected at over 1000 stream reaches. The sampled reaches were selected on a probability basis to represent the populat...

  1. Biocontrol attack exacerbates pollen-limitation in the invasive plant Centaurea solstitialis

    Science.gov (United States)

    Pollen-limited seed set is rarely studied in invasive plants despite the fact that >50% of the most problematic invaders in North America are pollinator-dependent. Further, pollinators are rarely considered in the use biocontrol agents to manage invaders. The ecological literature shows that herbivo...

  2. Chapter 4: Use of fire to manage populations of nonnative invasive plants

    Science.gov (United States)

    Peter M. Rice; Jane Kapler Smith

    2008-01-01

    It may be impossible to overstate the complexity of relationships among wildland ecosystems, fires, and nonnative invasives. Strategies for managing these relationships are similarly complex; they require information on local plant phenology, ability to produce various levels of fire severity within burns, willingness to combine fire with other management techniques,...

  3. Plant species invasions along the latitudinal gradient in the United States: Reply

    Science.gov (United States)

    Curtis H. Flather; Thomas J. Stohlgren; Catherine Jarnevich; David Barnett; John Kartesz

    2006-01-01

    We welcome the opportunity to respond to the comments of our colleagues, Fridley et al. (2006), on our recent paper (Stohlgren et al. 2005) regarding plant species invasions along latitudinal gradients. We agree on many aspects of this important line of research. In fact, the two major findings that they report from their analysis of floras are consistent with our main...

  4. 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

  5. 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 ...

  6. 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.

  7. 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.

  8. Spatio-temporal dynamics of plant invasions: Linking pattern to process

    Czech Academy of Sciences Publication Activity Database

    Pyšek, Petr; Hulme, P. E.

    2005-01-01

    Roč. 12, č. 3 (2005), s. 302-315 ISSN 1195-6860 R&D Projects: GA ČR(CZ) GA206/03/1216 Institutional research plan: CEZ:AV0Z60050516 Keywords : plant invasion * rate of spread * spatial scale Subject RIV: EF - Botanics Impact factor: 1.261, year: 2005

  9. 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

  10. 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 ecosystems * plant invasions * quarantine * Weed Risk Assessment Subject RIV: EH - Ecology, Behaviour Impact factor: 0.924, year: 2012

  11. 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 (...

  12. European map of alien plant invasions, based on the quantitative assessment across habitats

    Czech Academy of Sciences Publication Activity Database

    Chytrý, M.; Pyšek, Petr; Wild, Jan; Pino, J.; Maskell, L. C.; Vila, M.

    2009-01-01

    Roč. 15, č. 1 (2009), s. 98-107 ISSN 1366-9516 R&D Projects: GA MŠk LC06073 Grant - others:Evropská komise(XE) GOCE-CT-2003-506675 Institutional research plan: CEZ:AV0Z60050516 Keywords : plant invasions * habitat * Europe Subject RIV: EF - Botanics Impact factor: 4.224, year: 2009

  13. Restoration of native plant communities infested by invasive weeds -- Sawmill Creek Research Natural Area

    Science.gov (United States)

    Peter Rice

    2000-01-01

    Invasive alien weeds established themselves on the Sawmill Creek Research Natural Area, harming elk feeding grounds and threatening the integrity of the native plant community. Management enacted herbicide control over several growing seasons, resulting in greater elk winter forage on study plots. Monitoring the long-term effects of herbicide as a restoration tool...

  14. 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....

  15. Remote sensing bio-control damage on aquatic invasive alien plant ...

    African Journals Online (AJOL)

    Naeem

    Abstract. Aquatic Invasive Alien Plant (AIAP) species are a major threat to freshwater ecosystems, placing great strain on South Africa's limited water resources. Bio-control programmes have been initiated in an effort to mitigate the negative environmental impacts associated with their presence in non-native areas. Remote ...

  16. 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

  17. Predictors, spatial distribution, and occurrence of woody invasive plants in subtropical urban ecosystems

    Science.gov (United States)

    Christina L. Staudhammer; Francisco J. Escobedo; Nathan Holt; Linda J. Young; Thomas J. Brandeis; Wayne Zipperer; Other

    2015-01-01

    We examined the spatial distribution, occurrence, and socioecological predictors of woody invasive plants (WIP) in two subtropical, coastal urban ecosystems: San Juan, Puerto Rico and Miami-Dade, United States. These two cities have similar climates and ecosystems typical of subtropical regions but differ in socioeconomics, topography, and urbanization processes. Using...

  18. 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 plants * urban environment * species richness Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 3.615, year: 2016

  19. 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

  20. 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...

  1. 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

  2. The extent of selected non-native invasive plants on Missouri forestland

    Science.gov (United States)

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

    2008-01-01

    The Northern Research Station's Forest Inventory and Analysis Program (NRSFIA) collects forest-related data throughout a 24-state region in the northeastern United States, ranging from North Dakota to Maine and Kansas to Maryland. Based on discussions with stakeholders and others, NRS-FIA found that the impact of non-native invasive plants (NNIPs) may be known at...

  3. The invasion of southern forests by nonnative plants: current and future occupation, with impacts, management strategies, and mitigation approaches

    Science.gov (United States)

    James H. Miller; Dawn Lemke; John Coulston

    2013-01-01

    Key FindingsInvasive plants continue to escape into and spread through southern forests to eventually form exclusive infestations, and replace native communities to the detriment of forest productivity, biodiversity, ecosystem services, and human use potential.Over a 300-year period, invasive plants have been increasingly...

  4. Lower resistance and higher tolerance of invasive host plants: biocontrol agents reach high densities but exert weak control

    Science.gov (United States)

    1. Invasive plants often have novel biotic interactions in their introduced ranges. Changes in herbivore defense traits are important for the effectiveness of biological control, because insect natural enemies may rapidly build up their populations on invasive plants due to decreased resistance but...

  5. Non-native plant invasion along elevation and canopy closure gradients in a Middle Rocky Mountain ecosystem

    Science.gov (United States)

    Joshua P. Averett; Bruce McCune; Catherine G. Parks; Bridgett J. Naylor; Tim DelCurto; Ricardo Mata-Gonz??lez; RunGuo Zang

    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...

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Plant invasion phenomenon enhances reproduction performance in an endangered spider

    Science.gov (United States)

    Pétillon, Julien; Puzin, Charlène; Acou, Anthony; Outreman, Yannick

    2009-10-01

    Current models in evolutionary ecology predict life history alterations in response to habitat suitability to optimize fitness. Only few empirical studies have demonstrated how life history traits that are expected to trade off against each other differ among environments. In Europe, many salt marshes have been recently invaded by the grass Elymus athericus. Previous studies however showed higher densities of the endangered spider Arctosa fulvolineata (Araneae: Lycosidae) in invaded salt marshes compared to natural habitats, which suggests a lower habitat suitability in the latter. The aim of this study was to determine if this emerging habitat (1) affects the amount of resource acquisition and (2) alters the balance between life history traits that are expected to trade off against each other in this stenotopic salt marsh species. As suggested by theoretical studies, an optimization of fitness by increasing egg size at the cost of decreasing fecundity in unsuitable (i.e., natural) habitats was expected. Females presenting cocoon were then collected in close invaded and natural salt marsh areas within the Mont Saint-Michel Bay (France). By considering female mass as covariate, cocoon mass, number of eggs, and egg volume were compared between both habitats. Clutch mass was strongly determined by female mass in both habitats. Clutch mass was however significantly smaller in the natural habitat compared to the invaded habitat, indicating a higher resource acquisition in the latter. When correcting for female size, fecundity was additionally increased in the invaded habitat through a significant decrease in egg size. This phenotypic response can be explained by differences in habitat structure between invaded and natural habitats: the former offers a more complex litter favoring nocturnal wanderers like A. fulvolineata. The existence of such an adaptive reproduction strategy depending on habitat suitability constitutes an original case of an invasion that favors an

  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. 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.

  13. 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

  14. Mountain Matokit and Vrgorac city: a new localities of threatened and invasive plant taxa in Croatia

    Directory of Open Access Journals (Sweden)

    Mara Vukojević

    2012-03-01

    Full Text Available This paper is first inventarisation of threatened and invasive vascular plants on the rocky grasslands situated on northern slopes of mountain Matokit and abandoned arable land in vicinity of town of Vrgorac. These sites represent a new site for the Croatian flora. This research was conducted in year 2010 and 2011. We found 11 species of threatened vascular plants that by the Red Book (Nikolić and Topić [14] and Flora Croatica Database (Nikolić [13] and 15 invasive species, according to preliminary list of invasive alien species (IAS in Croatia (Boršić et al. [3]. In this paper the habitat of some species, their distribution in Croatia, life forms and floral elements are described. It was found that threatened species occur exclusively on the rocky grassland habitat, except two species: critically endangered (CR Papaver argemone and endangered (EN Hibiscus trionum which were recorded on arable land. All inventoried invasive species, were recorded at the abandoned arable land, except the species Robinia pseudoacacia. Tendency for uncontrolled spread showed species Ailanthus altissima and Ambrosia artemisiifolia. Habitats of rocky grassland are on the stage of secondary succession (healing with the forest, and on the arable land the spread of invasive species exist (due to socio-economic changes: abandonment of agriculture and animal husbandry, and depopulation of the population. The results of these studies are contribution to the distribution map of threatened and invasive species in Croatia, and to the conservation of grassland habitat study area, as well as to preventing of the spread of invasive species.

  15. Predicting trends of invasive plants richness using local socio-economic data: an application in North Portugal.

    Science.gov (United States)

    Santos, Mário; Freitas, Raul; Crespí, António L; Hughes, Samantha Jane; Cabral, João Alexandre

    2011-10-01

    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. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Resource-use strategies of native and invasive plants in Eastern North American forests.

    Science.gov (United States)

    Heberling, J Mason; Fridley, Jason D

    2013-10-01

    Studies in disturbed, resource-rich environments often show that invasive plants are more productive than co-occurring natives, but with similar physiological tradeoffs. However, in resource-limited habitats, it is unclear whether native and invasive plants have similar metabolic constraints or if invasive plants are more productive per unit resource cost - that is, use resources more efficiently. Using a common garden to control for environment, we compared leaf physiological traits relating to resource investments, carbon returns, and resource-use efficiencies in 14 native and 18 nonnative invasive species of common genera found in Eastern North American (ENA) deciduous forest understories, where growth is constrained by light and nutrient limitation. Despite greater leaf construction and nitrogen costs, invaders exhibited greater instantaneous photosynthetic energy-use efficiency (PEUE) and marginally greater photosynthetic nitrogen-use efficiency (PNUE). When integrated over leaf lifespan (LL), these differences were magnified. Differences in efficiency were driven by greater productivity per unit leaf investment, as invaders exhibited both greater photosynthetic abilities and longer LL. Our results indicate that woody understory invaders in ENA forests are not constrained to the same degree by leaf-based metabolic tradeoffs as the native understory flora. These strategy differences could be attributable to pre-adaptation in the native range, although other explanations are possible. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  17. Non-native megaherbivores: the case for novel function to manage plant invasions on islands.

    Science.gov (United States)

    Hansen, Dennis M

    2015-07-20

    There is a heated debate about whether all non-native species are 'guilty until proven innocent', or whether some should be accepted or even welcomed. Further fanning the flames, I here present a case where introductions of carefully vetted, non-native species could provide a net conservation benefit. On many islands, native megaherbivores (flightless birds, tortoises) recently went extinct. Here, rewilding with carefully selected non-native species as ecological replacements is increasingly considered a solution, reinstating a herbivory regime that largely benefits the native flora. Based on these efforts, I suggest that restoration practitioners working on islands without a history of native megaherbivores that are threatened by invasive plants should consider introducing a non-native island megaherbivore, and that large and giant tortoises are ideal candidates. Such tortoises would be equally useful on islands where eradication of invasive mammals has led to increased problems with invasive plants, or on islands that never had introduced mammalian herbivores, but where invasive plants are a problem. My proposal may seem radical, but the reversibility of using giant tortoises means that nothing is lost from trying, and that indeed much is to be gained. As an easily regulated adaptive management tool, it represents an innovative, hypothesis-driven 'innocent until proven guilty' approach. Published by Oxford University Press on behalf of the Annals of Botany Company.

  18. Hyperspectral remote sensing tools for quantifying plant litter and invasive species in arid ecosystems

    Science.gov (United States)

    Nagler, Pamela L.; Sridhar, B.B. Maruthi; Olsson, Aaryn Dyami; Glenn, Edward P.; van Leeuwen, Willem J.D.; Thenkabail, Prasad S.; Huete, Alfredo; Lyon, John G.

    2012-01-01

    Green vegetation can be distinguished using visible and infrared multi-band and hyperspectral remote sensing methods. The problem has been in identifying and distinguishing the non-photosynthetically active radiation (PAR) landscape components, such as litter and soils, and from green vegetation. Additionally, distinguishing different species of green vegetation is challenging using the relatively few bands available on most satellite sensors. This chapter focuses on hyperspectral remote sensing characteristics that aim to distinguish between green vegetation, soil, and litter (or senescent vegetation). Quantifying litter by remote sensing methods is important in constructing carbon budgets of natural and agricultural ecosystems. Distinguishing between plant types is important in tracking the spread of invasive species. Green leaves of different species usually have similar spectra, making it difficult to distinguish between species. However, in this chapter we show that phenological differences between species can be used to detect some invasive species by their distinct patterns of greening and dormancy over an annual cycle based on hyperspectral data. Both applications require methods to quantify the non-green cellulosic fractions of plant tissues by remote sensing even in the presence of soil and green plant cover. We explore these methods and offer three case studies. The first concerns distinguishing surface litter from soil using the Cellulose Absorption Index (CAI), as applied to no-till farming practices where plant litter is left on the soil after harvest. The second involves using different band combinations to distinguish invasive saltcedar from agricultural and native riparian plants on the Lower Colorado River. The third illustrates the use of the CAI and NDVI in time-series analyses to distinguish between invasive buffelgrass and native plants in a desert environment in Arizona. Together the results show how hyperspectral imagery can be applied to

  19. Fault diagnosis of nuclear power plant based on invasive weed optimization algorithm

    International Nuclear Information System (INIS)

    Duan Mengqiang; Yuan Can

    2015-01-01

    It is not completely accordant for fault reasons to match up corresponding symptoms of the marine nuclear power plant. A kind of fault diagnosis method was proposed, which is about invasive weed optimization algorithm combined with probability causal model. The probability causal model likelihood function was used as fitness function of the invasive weed optimization algorithm, after that the fault diagnosis of complex systems can be converted to optimization problem. The simulation results show that the method can not only be used for the process of diagnosis of uncertainty, but also for the purpose of multiple symptoms to multiple faults diagnose with high reliability and practicability. (authors)

  20. 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.

  1. 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

  2. What do we really know about alien plant invasion? A review of the invasion mechanism of one of the world's worst weeds.

    Science.gov (United States)

    Bajwa, Ali Ahsan; Chauhan, Bhagirath Singh; Farooq, Muhammad; Shabbir, Asad; Adkins, Steve William

    2016-07-01

    This review provides an insight into alien plant invasion taking into account the invasion mechanism of parthenium weed ( Parthenium hysterophorus L.). A multi-lateral understanding of the invasion biology of this weed has pragmatic implications for weed ecology and management. Biological invasions are one of the major drivers of restructuring and malfunctioning of ecosystems. Invasive plant species not only change the dynamics of species composition and biodiversity but also hinder the system productivity and efficiency in invaded regions. Parthenium weed, a well-known noxious invasive species, has invaded diverse climatic and biogeographic regions in more than 40 countries across five continents. Efforts are under way to minimize the parthenium weed-induced environmental, agricultural, social, and economic impacts. However, insufficient information regarding its invasion mechanism and interference with ecosystem stability is available. It is hard to devise effective management strategies without understanding the invasion process. Here, we reviewed the mechanism of parthenium weed invasion. Our main conclusions are: (1) morphological advantages, unique reproductive biology, competitive ability, escape from natural enemies in non-native regions, and a C3/C4 photosynthesis are all likely to be involved in parthenium weed invasiveness. (2) Tolerance to abiotic stresses and ability to grow in wide range of edaphic conditions are thought to be additional invasion tools on a physiological front. (3) An allelopathic potential of parthenium weed against crop, weed and pasture species, with multiple modes of allelochemical expression, may also be responsible for its invasion success. Moreover, the release of novel allelochemicals in non-native environments might have a pivotal role in parthenium weed invasion. (4) Genetic diversity found among different populations and biotypes of parthenium weed, based on geographic, edaphic, climatic, and ecological ranges, might also

  3. 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.

  4. Contemporary Remotely Sensed Data Products Refine Invasive Plants Risk Mapping in Data Poor Regions.

    Science.gov (United States)

    Truong, Tuyet T A; Hardy, Giles E St J; Andrew, Margaret E

    2017-01-01

    Invasive weeds are a serious problem worldwide, threatening biodiversity and damaging economies. Modeling potential distributions of invasive weeds can prioritize locations for monitoring and control efforts, increasing management efficiency. Forecasts of invasion risk at regional to continental scales are enabled by readily available downscaled climate surfaces together with an increasing number of digitized and georeferenced species occurrence records and species distribution modeling techniques. However, predictions at a finer scale and in landscapes with less topographic variation may require predictors that capture biotic processes and local abiotic conditions. Contemporary remote sensing (RS) data can enhance predictions by providing a range of spatial environmental data products at fine scale beyond climatic variables only. In this study, we used the Global Biodiversity Information Facility (GBIF) and empirical maximum entropy (MaxEnt) models to model the potential distributions of 14 invasive plant species across Southeast Asia (SEA), selected from regional and Vietnam's lists of priority weeds. Spatial environmental variables used to map invasion risk included bioclimatic layers and recent representations of global land cover, vegetation productivity (GPP), and soil properties developed from Earth observation data. Results showed that combining climate and RS data reduced predicted areas of suitable habitat compared with models using climate or RS data only, with no loss in model accuracy. However, contributions of RS variables were relatively limited, in part due to uncertainties in the land cover data. We strongly encourage greater adoption of quantitative remotely sensed estimates of ecosystem structure and function for habitat suitability modeling. Through comprehensive maps of overall predicted area and diversity of invasive species, we found that among lifeforms (herb, shrub, and vine), shrub species have higher potential invasion risk in SEA. Native

  5. Contemporary Remotely Sensed Data Products Refine Invasive Plants Risk Mapping in Data Poor Regions

    Directory of Open Access Journals (Sweden)

    Tuyet T. A. Truong

    2017-05-01

    Full Text Available Invasive weeds are a serious problem worldwide, threatening biodiversity and damaging economies. Modeling potential distributions of invasive weeds can prioritize locations for monitoring and control efforts, increasing management efficiency. Forecasts of invasion risk at regional to continental scales are enabled by readily available downscaled climate surfaces together with an increasing number of digitized and georeferenced species occurrence records and species distribution modeling techniques. However, predictions at a finer scale and in landscapes with less topographic variation may require predictors that capture biotic processes and local abiotic conditions. Contemporary remote sensing (RS data can enhance predictions by providing a range of spatial environmental data products at fine scale beyond climatic variables only. In this study, we used the Global Biodiversity Information Facility (GBIF and empirical maximum entropy (MaxEnt models to model the potential distributions of 14 invasive plant species across Southeast Asia (SEA, selected from regional and Vietnam’s lists of priority weeds. Spatial environmental variables used to map invasion risk included bioclimatic layers and recent representations of global land cover, vegetation productivity (GPP, and soil properties developed from Earth observation data. Results showed that combining climate and RS data reduced predicted areas of suitable habitat compared with models using climate or RS data only, with no loss in model accuracy. However, contributions of RS variables were relatively limited, in part due to uncertainties in the land cover data. We strongly encourage greater adoption of quantitative remotely sensed estimates of ecosystem structure and function for habitat suitability modeling. Through comprehensive maps of overall predicted area and diversity of invasive species, we found that among lifeforms (herb, shrub, and vine, shrub species have higher potential invasion

  6. 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.

  7. 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.

  8. 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.

  9. The Coastal Squeeze: Rising seas and upland plant invasions differentially affect vertical exchange of greenhouse gases

    Science.gov (United States)

    Quinn, R. K.; Moseman-Valtierra, S.; Kroeger, K. D.; Martin, R.; Abdul-Aziz, O. I.; Ishtiaq, K. S.; Brannon, E.; Egan, K.; Tang, J.

    2016-02-01

    Biological invasions and sea level rise may significantly alter greenhouse gas fluxes from coastal marshes and their roles as major global carbon sinks. A spatial gradient in a coastal wetland was used to test how greenhouse gas fluxes may vary in response to either invasion by Phragmites australis or inundation by sea level rise. Net fluxes of CO2, N2O, and CH4 were compared between four zones of a New England coastal marsh (Sage Lot Pond, MA): the native low (Spartina alterniflora) and high marsh vegetation zones (Distichlis spicata and Juncus gerardii- dominated), invasive Phragmites australis zones, and permanently inundated, bare ponds. To test for potential proxies of greenhouse gas fluxes, plant properties were analyzed for relationships to CO2 or CH4 fluxes using a multivariate non-linear data-analytics model. Gas fluxes were also measured from a range of differently sized ponds and compared to die-back areas in two additional RI marshes. High precision infrared-based spectrometers were used to measure the gas fluxes in flux chambers. Among the native marsh zones, greatest CO2 uptake rates were found in S. alterniflora low marsh zones (averaging from -1 to -14 µmol CO2 m-2 s-1). Further, invasive Phragmites zones displayed significantly larger CO2 uptake rates (-7 to -15 µmol CO2 m-2 s-1) than the native (high) marsh zone (sinks nor sources). Among the plant properties in this study, belowground biomass was the strongest proxy for CO2 fluxes in native marsh zones, while abiotic properties are more likely to drive shifts in methane fluxes. Gas fluxes in multiple ponds and adjacent die back areas suggest a successional transition from strong C sinks in vegetated marshes to C sources. These findings signal clear potential for two alternative ecosystem fates- either inundation by rising seas or alteration by biological plant invasions- to produce opposite impacts on marsh carbon cycling.

  10. Response of an invasive native wetland plant to environmental flows: implications for managing regulated floodplain ecosystems.

    Science.gov (United States)

    Vivian, Lyndsey M; Marshall, David J; Godfree, Robert C

    2014-01-01

    The natural flow regimes of rivers underpin the health and function of floodplain ecosystems. However, infrastructure development and the over-extraction of water has led to the alteration of natural flow regimes, resulting in the degradation of river and floodplain habitats globally. In many catchments, including Australia's Murray-Darling Basin, environmental flows are seen as a potentially useful tool to restore natural flow regimes and manage the degradation of rivers and their associated floodplains. In this paper, we investigated whether environmental flows can assist in controlling an invasive native floodplain plant in Barmah Forest, south-eastern Australia. We experimentally quantified the effects of different environmental flow scenarios, including a shallow (20 cm) and deeper (50 cm) flood of different durations (12 and 20 weeks), as well as drought and soil-saturated conditions, on the growth and survival of seedlings of Juncus ingens, a native emergent macrophyte that has become invasive in some areas of Barmah Forest following river regulation and alteration of natural flow regimes. Three height classes of J. ingens (33 cm, 17 cm and 12 cm) were included in the experiment to explicitly test for relationships between treatments, plant survival and growth, and plant height. We found that seedling mortality occurred in the drought treatment and in the 20-week flood treatments of both depths; however, mortality rates in the flood treatments depended on initial plant height, with medium and short plants (initial heights of ≤17 cm) exhibiting the highest mortality rates. Both the 20 cm and 50 cm flood treatments of only 12 weeks duration were insufficient to cause mortality in any of the height classes; indeed, shoots of plants in the 20 cm flood treatment were able to elongate through the water surface at rapid rates. Our findings have important implications for management of Barmah Forest and floodplain ecosystems elsewhere, as it demonstrates

  11. Genetic uniformity characterizes the invasive spread of water hyacinth (Eichhornia crassipes), a clonal aquatic plant.

    Science.gov (United States)

    Zhang, Yuan-Ye; Zhang, Da-Yong; Barrett, Spencer C H

    2010-05-01

    Aquatic plant invasions are often associated with long-distance dispersal of vegetative propagules and prolific clonal reproduction. These reproductive features combined with genetic bottlenecks have the potential to severely limit genetic diversity in invasive populations. To investigate this question we conducted a global scale population genetic survey using amplified fragment length polymorphism markers of the world's most successful aquatic plant invader -Eichhornia crassipes (water hyacinth). We sampled 1140 ramets from 54 populations from the native (South America) and introduced range (Asia, Africa, Europe, North America, Central America and the Caribbean). Although we detected 49 clones, introduced populations exhibited very low genetic diversity and little differentiation compared with those from the native range, and approximately 80% of introduced populations were composed of a single clone. A widespread clone ('W') detected in two Peruvian populations accounted for 70.9% of the individuals sampled and dominated in 74.5% of the introduced populations. However, samples from Bangladesh and Indonesia were composed of different genotypes, implicating multiple introductions to the introduced range. Nine of 47 introduced populations contained clonal diversity suggesting that sexual recruitment occurs in some invasive sites where environmental conditions favour seedling establishment. The global patterns of genetic diversity in E. crassipes likely result from severe genetic bottlenecks during colonization and prolific clonal propagation. The prevalence of the 'W' genotype throughout the invasive range may be explained by stochastic sampling, or possibly because of pre-adaptation of the 'W' genotype to tolerate low temperatures.

  12. Simulating plant invasion dynamics in mountain ecosystems under global change scenarios.

    Science.gov (United States)

    Carboni, Marta; Guéguen, Maya; Barros, Ceres; Georges, Damien; Boulangeat, Isabelle; Douzet, Rolland; Dullinger, Stefan; Klonner, Guenther; van Kleunen, Mark; Essl, Franz; Bossdorf, Oliver; Haeuser, Emily; Talluto, Matthew V; Moser, Dietmar; Block, Svenja; Conti, Luisa; Dullinger, Iwona; Münkemüller, Tamara; Thuiller, Wilfried

    2018-01-01

    Across the globe, invasive alien species cause severe environmental changes, altering species composition and ecosystem functions. So far, mountain areas have mostly been spared from large-scale invasions. However, climate change, land-use abandonment, the development of tourism and the increasing ornamental trade will weaken the barriers to invasions in these systems. Understanding how alien species will react and how native communities will influence their success is thus of prime importance in a management perspective. Here, we used a spatially and temporally explicit simulation model to forecast invasion risks in a protected mountain area in the French Alps under future conditions. We combined scenarios of climate change, land-use abandonment and tourism-linked increases in propagule pressure to test if the spread of alien species in the region will increase in the future. We modelled already naturalized alien species and new ornamental plants, accounting for interactions among global change components, and also competition with the native vegetation. Our results show that propagule pressure and climate change will interact to increase overall species richness of both naturalized aliens and new ornamentals, as well as their upper elevational limits and regional range-sizes. Under climate change, woody aliens are predicted to more than double in range-size and herbaceous species to occupy up to 20% of the park area. In contrast, land-use abandonment will open new invasion opportunities for woody aliens, but decrease invasion probability for naturalized and ornamental alien herbs as a consequence of colonization by native trees. This emphasizes the importance of interactions with the native vegetation either for facilitating or potentially for curbing invasions. Overall, our work highlights an additional and previously underestimated threat for the fragile mountain flora of the Alps already facing climate changes, land-use transformations and overexploitation by

  13. Impacts of invasive plants on Sandhill Crane (Grus canadensis) roosting habitat

    Science.gov (United States)

    Kessler, Andrew C.; Merchant, James W.; Allen, Craig R.; Shultz, Steven D.

    2011-01-01

    Invasive plants continue to spread in riparian ecosystems, causing both ecological and economic damage. This research investigated the impacts of common reed, purple loosestrife, riparian shrubland, and riparian woodlands on the quality and quantity of sandhill crane roosting habitat in the central Platte River, Nebraska, using a discrete choice model. A more detailed investigation of the impacts of common reed on sandhill crane roosting habitat was performed by forecasting a spread or contraction of this invasive plant. The discrete choice model indicates that riparian woodlands had the largest negative impact on sandhill crane roosting habitat. The forecasting results predict that a contraction of common reed could increase sandhill crane habitat availability by 50%, whereas an expansion could reduce the availability by as much as 250%. This suggests that if the distribution of common reed continues to expand in the central Platte River the availability of sandhill crane roosting habitat would likely be greatly reduced.

  14. Managing invasive aquatic plants in a changing system: strategic consideration of ecosystem services.

    Science.gov (United States)

    Hershner, Carl; Havens, Kirk J

    2008-06-01

    Climate change is projected to increase stress for many coastal plant communities. Along large portions of the North American coast, habitat degradation from anthropogenic changes to the environment already threaten the community structure of tidal marshes and submerged aquatic grass beds. The potential loss of ecological services historically provided by these communities has been a long-standing rationale for aggressive control of invading plants such as Phragmites australis and Hydrilla verticillata. Increasing evidence of ecological services provided by invasive species such as P. australis and H. verticillata suggest that, in the face of increasing stress, it may be prudent to take a more pragmatic approach regarding the effect of these species on coastal ecosystems. The notable resilience of these species to control efforts and their competitive success and comparative vigor in stressed systems and capacity to provide at least some beneficial services combine to suggest some invasive species may have a useful role in managed coastal ecosystems.

  15. 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

  16. Planting intensity, residence time, and species traits determine invasion success of alien woody species

    Czech Academy of Sciences Publication Activity Database

    Pyšek, Petr; Křivánek, Martin; Jarošík, Vojtěch

    2009-01-01

    Roč. 90, č. 10 (2009), s. 2734-2744 ISSN 0012-9658 R&D Projects: GA ČR GA206/05/0323; GA MŠk LC06073 Grant - others:Evropská komise(XE) GOCE-CT-2003-506675 ALARM Institutional research plan: CEZ:AV0Z60050516 Keywords : woody species * invasion * planting Subject RIV: EF - Botanics Impact factor: 4.411, year: 2009

  17. 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

  18. 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

  19. 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

  20. Improved Predictions of the Geographic Distribution of Invasive Plants Using Climatic Niche Models.

    Science.gov (United States)

    Ramírez-Albores, Jorge E; Bustamante, Ramiro O; Badano, Ernesto I

    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

  1. 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

  2. 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.

  3. Lineage overwhelms environmental conditions in determining rhizosphere bacterial community structure in a cosmopolitan invasive plant.

    Science.gov (United States)

    Bowen, Jennifer L; Kearns, Patrick J; Byrnes, Jarrett E K; Wigginton, Sara; Allen, Warwick J; Greenwood, Michael; Tran, Khang; Yu, Jennifer; Cronin, James T; Meyerson, Laura A

    2017-09-05

    Plant-microbe interactions play crucial roles in species invasions but are rarely investigated at the intraspecific level. Here, we study these interactions in three lineages of a globally distributed plant, Phragmites australis. We use field surveys and a common garden experiment to analyze bacterial communities in the rhizosphere of P. australis stands from native, introduced, and Gulf lineages to determine lineage-specific controls on rhizosphere bacteria. We show that within-lineage bacterial communities are similar, but are distinct among lineages, which is consistent with our results in a complementary common garden experiment. Introduced P. australis rhizosphere bacterial communities have lower abundances of pathways involved in antimicrobial biosynthesis and degradation, suggesting a lower exposure to enemy attack than native and Gulf lineages. However, lineage and not rhizosphere bacterial communities dictate individual plant growth in the common garden experiment. We conclude that lineage is crucial for determination of both rhizosphere bacterial communities and plant fitness.Environmental factors often outweigh host heritable factors in structuring host-associated microbiomes. Here, Bowen et al. show that host lineage is crucial for determination of rhizosphere bacterial communities in Phragmites australis, a globally distributed invasive plant.

  4. Size-symmetric competition in a shade-tolerant invasive plant

    DEFF Research Database (Denmark)

    Pan, Xiao-Yun; Weiner, Jacob; Li, Bo

    2013-01-01

    Plant responses to crowding have been investigated extensively in stands of light‐demanding species, but shade‐tolerant species may react differently. In the present study, we investigated the effect of density on the mortality, size inequality, and biomass allocation of Alternanthera philoxeroides......, 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...

  5. 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

  6. 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

  7. Simulating the interactions of forest structure, fire regime, and plant invasion in the southern Appalachians using LANDIS

    Science.gov (United States)

    Weimin Xi; Szu-Hung Chen; Andrew G. Birt; John D. Waldron; Charles W. Lafon; David M. Cairns; Maria D. Tchakerian; Kier D. Klepzig; Robert N. Coulson

    2011-01-01

    Southern Appalachian forests face multiple environmental threats, including periodic fires, insect outbreaks, and more recently, exotic invasive plants. Past studies suggest these multiple disturbances interact to shape species-rich forest landscape, and they hypothesize that changes in fire regimes and increasing landscape fragmentation may influence invasive...

  8. 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

  9. 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...

  10. The Human Release Hypothesis for biological invasions: human activity as a determinant of the abundance of invasive plant species.

    Science.gov (United States)

    Zimmermann, Heike; Brandt, Patric; Fischer, Joern; Welk, Erik; von Wehrden, Henrik

    2014-01-01

    Research on biological invasions has increased rapidly over the past 30 years, generating numerous explanations of how species become invasive. While the mechanisms of invasive species establishment are well studied, the mechanisms driving abundance patterns (i.e. patterns of population density and population size) remain poorly understood. It is assumed that invasive species typically have higher abundances in their new environments than in their native ranges, and patterns of invasive species abundance differ between invaded regions. To explain differences in invasive species abundance, we propose the Human Release Hypothesis. In parallel to the established Enemy Release Hypothesis, this hypothesis states that the differences in abundance of invasive species are found between regions because population expansion is reduced in some regions through continuous land management and associated cutting of the invasive species. The Human Release Hypothesis does not negate other important drivers of species invasions, but rather should be considered as a potentially important complementary mechanism. We illustrate the hypothesis via a case study on an invasive rose species, and hypothesize which locations globally may be most likely to support high abundances of invasive species. We propose that more extensive empirical work on the Human Release Hypothesis could be useful to test its general applicability.

  11. 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.

  12. 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...

  13. Specialist Insect Herbivore and Light Availability Do Not Interact in the Evolution of an Invasive Plant.

    Science.gov (United States)

    Zhang, Zhijie; Pan, Xiaoyun; Zhang, Ziyan; He, Kate S; Li, Bo

    2015-01-01

    Release from specialist insect herbivores may allow invasive plants to evolve traits associated with decreased resistance and increased competitive ability. Given that there may be genetic trade-off between resistance and tolerance, invasive plants could also become more tolerant to herbivores. Although it is widely acknowledged that light availability affects tolerance to herbivores, little information is available for whether the effect of light availability on tolerance differ between the introduced and native populations. We conducted a common garden experiment in the introduced range of Alternanthera philoxeroides using ten invasive US and ten native Argentinean populations at two levels of light availability and in the presence or absence of a specialist stem-boring insect Agasicles hygrophila. Plant biomass (total and storage root biomass), two allocation traits (root/shoot ratio and branch intensity, branches biomass/main stem biomass) and two functional traits (specific stem length and specific leaf area), which are potentially associated with herbivore resistance and light capture, were measured. Overall, we found that A. philoxeroides from introduced ranges had comparable biomass and tolerance to specialist herbivores, lower branch intensity, lower specific stem length and specific leaf area. Moreover, introduced populations displayed higher shade tolerance of storage root biomass and lower plastic response to shading in specific stem length. Finally, light availability had no significant effect on evolution of tolerance to specialist herbivores of A. philoxeroides. Our results suggest that post-introduction evolution might have occurred in A. philoxeroides. While light availability did not influence the evolution of tolerance to specialist herbivores, increased shade tolerance and release from specialist insects might have contributed to the successful invasion of A. philoxeroides.

  14. Specialist Insect Herbivore and Light Availability Do Not Interact in the Evolution of an Invasive Plant.

    Directory of Open Access Journals (Sweden)

    Zhijie Zhang

    Full Text Available Release from specialist insect herbivores may allow invasive plants to evolve traits associated with decreased resistance and increased competitive ability. Given that there may be genetic trade-off between resistance and tolerance, invasive plants could also become more tolerant to herbivores. Although it is widely acknowledged that light availability affects tolerance to herbivores, little information is available for whether the effect of light availability on tolerance differ between the introduced and native populations. We conducted a common garden experiment in the introduced range of Alternanthera philoxeroides using ten invasive US and ten native Argentinean populations at two levels of light availability and in the presence or absence of a specialist stem-boring insect Agasicles hygrophila. Plant biomass (total and storage root biomass, two allocation traits (root/shoot ratio and branch intensity, branches biomass/main stem biomass and two functional traits (specific stem length and specific leaf area, which are potentially associated with herbivore resistance and light capture, were measured. Overall, we found that A. philoxeroides from introduced ranges had comparable biomass and tolerance to specialist herbivores, lower branch intensity, lower specific stem length and specific leaf area. Moreover, introduced populations displayed higher shade tolerance of storage root biomass and lower plastic response to shading in specific stem length. Finally, light availability had no significant effect on evolution of tolerance to specialist herbivores of A. philoxeroides. Our results suggest that post-introduction evolution might have occurred in A. philoxeroides. While light availability did not influence the evolution of tolerance to specialist herbivores, increased shade tolerance and release from specialist insects might have contributed to the successful invasion of A. philoxeroides.

  15. 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.

  16. 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.

  17. 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 * Weed s Subject RIV: EF - Botanics Impact factor: 1.730, year: 2008

  18. 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

  19. 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.

  20. Sentinel trees as a tool to forecast invasions of alien plant pathogens.

    Directory of Open Access Journals (Sweden)

    AnnaMaria Vettraino

    Full Text Available Recent disease outbreaks caused by alien invasive pathogens into European forests posed a serious threat to forest sustainability with relevant environmental and economic effects. Many of the alien tree pathogens recently introduced into Europe were not previously included on any quarantine lists, thus they were not subject to phytosanitary inspections. The identification and description of alien fungi potentially pathogenic to native European flora before their introduction in Europe, is a paramount need in order to limit the risk of invasion and the impact to forest ecosystems. To determine the potential invasive fungi, a sentinel trees plot was established in Fuyang, China, using healthy seedlings of European tree species including Quercus petreae, Q. suber, and Q. ilex. The fungal assemblage associated with symptomatic specimens was studied using the tag-encoded 454 pyrosequencing of the nuclear ribosomal internal transcribed spacer-1 (ITS 1. Taxa with probable Asiatic origin were identified and included plant pathogenic genera. These results indicate that sentinel plants may be a strategic tool to improve the prevention of bioinvasions.

  1. Soil-occupancy effects of invasive and native grassland plant species on composition and diversity of mycorrhizal associations

    Science.gov (United States)

    Jordan, Nicholas R.; Aldrich-Wolfe, Laura; Huerd, Sheri C.; Larson, Diane L.; Muehlbauer, Gary

    2012-01-01

    Diversified grasslands that contain native plant species can produce biofuels, support sustainable grazing systems, and produce other ecosystem services. However, ecosystem service production can be disrupted by invasion of exotic perennial plants, and these plants can have soil-microbial “legacies” that may interfere with establishment and maintenance of diversified grasslands even after effective management of the invasive species. The nature of such legacies is not well understood, but may involve suppression of mutualisms between native species and soil microbes. In this study, we tested the hypotheses that legacy effects of invasive species change colonization rates, diversity, and composition of arbuscular-mycorrhizal fungi (AMF) associated with seedlings of co-occurring invasive and native grassland species. In a glasshouse, experimental soils were conditioned by cultivating three invasive grassland perennials, three native grassland perennials, and a native perennial mixture. Each was grown separately through three cycles of growth, after which we used T-RFLP analysis to characterize AMF associations of seedlings of six native perennial and six invasive perennial species grown in these soils. Legacy effects of soil conditioning by invasive species did not affect AMF richness in seedling roots, but did affect AMF colonization rates and the taxonomic composition of mycorrhizal associations in seedling roots. Moreover, native species were more heavily colonized by AMF and roots of native species had greater AMF richness (number of AMF operational taxonomic units per seedling) than did invasive species. The invasive species used to condition soil in this experiment have been shown to have legacy effects on biomass of native seedlings, reducing their growth in this and a previous similar experiment. Therefore, our results suggest that successful plant invaders can have legacies that affect soil-microbial associations of native plants and that these effects

  2. 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.

  3. 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-...

  4. 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,

  5. 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.

  6. Propagule success of an invasive Poaceae depends on size of parental plants

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    Fabielle Mucio Bando

    Full Text Available Abstract: Aim Viability and successful colonization of propagules by an invasive species may depend on several factors, such as parental plant size and propagules’ fresh mass. Here, we tested (i the effects of propagules’ origin (from large and small parental plants; (ii the position in the parental stem (apical, intermediate and basal on the early development of the new sprouts of Urochloa arrecta; and (iii if the regeneration success of U. arrecta was related with propagule fresh mass that comes from large or small parental plants. Methods We selected 16 individuals of U. arrecta and separated them in two groups: (i eight “large” (stem ± 1.5 m and (ii eight “small” (stem ± 0.6 m. For each individual, we cut three fragments with two nodes (considered as the “propagule” from the apical, intermediate and basal portions of the stem and we measured the fresh mass (g, length (cm and distance between the two nodes (cm of all propagules of U. arrecta. In addition, after the experimentation, we measured the dry mass (g and length (cm of each new sprout of U. arrecta generated from each propagule. Results We found that large parental individuals produced sprouts with longer length and greater dry mass. In contrast, the position in the parental stem did not significant influence the development of sprouts in U. arrecta. In addition, the propagule fresh mass played a role in the development of sprouts just for propagules from small parental plants. Conclusions We found that the size of the parental individual is an important determinant of the development of new sprouts of this invasive species and the propagule fresh mass has a positive and significant influence in the success of U. arrecta only for propagules from smaller parental plants. We highlight that all propagules were viable, which could explain the reasons for this plant to be a successful invader.

  7. Meta-analysis reveals evolution in invasive plant species but little support for Evolution of Increased Competitive Ability (EICA).

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    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.

  8. Invasive Species

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    Invasive species have significantly changed the Great Lakes ecosystem. An invasive species is a plant or animal that is not native to an ecosystem, and whose introduction is likely to cause economic, human health, or environmental damage.

  9. 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.

  10. Alien plants introduced by different pathways differ in invasion success: unintentional introductions as a threat to natural areas.

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    Petr Pyšek

    Full Text Available BACKGROUND: Understanding the dimensions of pathways of introduction of alien plants is important for regulating species invasions, but how particular pathways differ in terms of post-invasion success of species they deliver has never been rigorously tested. We asked whether invasion status, distribution and habitat range of 1,007 alien plant species introduced after 1500 A.D. to the Czech Republic differ among four basic pathways of introduction recognized for plants. PRINCIPAL FINDINGS: Pathways introducing alien species deliberately as commodities (direct release into the wild; escape from cultivation result in easier naturalization and invasion than pathways of unintentional introduction (contaminant of a commodity; stowaway arriving without association with it. The proportion of naturalized and invasive species among all introductions delivered by a particular pathway decreases with a decreasing level of direct assistance from humans associated with that pathway, from release and escape to contaminant and stowaway. However, those species that are introduced via unintentional pathways and become invasive are as widely distributed as deliberately introduced species, and those introduced as contaminants invade an even wider range of seminatural habitats. CONCLUSIONS: Pathways associated with deliberate species introductions with commodities and pathways whereby species are unintentionally introduced are contrasting modes of introductions in terms of invasion success. However, various measures of the outcome of the invasion process, in terms of species' invasion success, need to be considered to accurately evaluate the role of and threat imposed by individual pathways. By employing various measures we show that invasions by unintentionally introduced plant species need to be considered by management as seriously as those introduced by horticulture, because they invade a wide range of seminatural habitats, hence representing even a greater

  11. Parallel evolution in an invasive plant: effect of herbivores on competitive ability and regrowth of Jacobaea vulgaris.

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    Lin, Tiantian; Klinkhamer, Peter G L; Vrieling, Klaas

    2015-07-01

    A shift in the composition of the herbivore guild in the invasive range is expected to select for plants with a higher competitive ability, a lower regrowth capacity and a lower investment in defence. We show here that parallel evolution took place in three geographically distinct invasive regions that differed significantly in climatic conditions. This makes it most likely that indeed the shifts in herbivore guilds were causal to the evolutionary changes. We studied competitive ability and regrowth of invasive and native Jacobaea vulgaris using an intraspecific competition set-up with and without herbivory. Without herbivores invasive genotypes have a higher competitive ability than native genotypes. The invasive genotypes were less preferred by the generalist Mamestra brassicae but more preferred by the specialist Tyria jacobaeae, consequently their competitive ability was significantly increased by the first and reduced by the latter. Invasive genotypes showed a lower regrowth ability in both herbivore treatments. © 2015 John Wiley & Sons Ltd/CNRS.

  12. Climate alters response of an endemic island plant to removal of invasive herbivores

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    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

  13. Invasive species management restores a plant-pollinator mutualism in Hawaii

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    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

  14. Historic Mining and Agriculture as Indicators of Occurrence and Abundance of Widespread Invasive Plant Species

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    Calinger, Kellen; Calhoon, Elisabeth; Chang, Hsiao-chi; Whitacre, James; Wenzel, John; Comita, Liza; Queenborough, Simon

    2015-01-01

    Anthropogenic disturbances often change ecological communities and provide opportunities for non-native species invasion. Understanding the impacts of disturbances on species invasion is therefore crucial for invasive species management. We used generalized linear mixed effects models to explore the influence of land-use history and distance to roads on the occurrence and abundance of two invasive plant species (Rosa multiflora and Berberis thunbergii) in a 900-ha deciduous forest in the eastern U.S.A., the Powdermill Nature Reserve. Although much of the reserve has been continuously forested since at least 1939, aerial photos revealed a variety of land-uses since then including agriculture, mining, logging, and development. By 2008, both R. multiflora and B. thunbergii were widespread throughout the reserve (occurring in 24% and 13% of 4417 10-m diameter regularly-placed vegetation plots, respectively) with occurrence and abundance of each varying significantly with land-use history. Rosa multiflora was more likely to occur in historically farmed, mined, logged or developed plots than in plots that remained forested, (log odds of 1.8 to 3.0); Berberis thunbergii was more likely to occur in plots with agricultural, mining, or logging history than in plots without disturbance (log odds of 1.4 to 2.1). Mining, logging, and agriculture increased the probability that R. multiflora had >10% cover while only past agriculture was related to cover of B. thunbergii. Proximity to roads was positively correlated with the occurrence of R. multiflora (a 0.26 increase in the log odds for every 1-m closer) but not B. thunbergii, and roads had no impact on the abundance of either species. Our results indicated that a wide variety of disturbances may aid the introduction of invasive species into new habitats, while high-impact disturbances such as agriculture and mining increase the likelihood of high abundance post-introduction. PMID:26046534

  15. Legume-rhizobium symbiotic promiscuity and effectiveness do not affect plant invasiveness.

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    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.

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

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    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

  17. Invasive alien plants in Croatia as a threat to biodiversity of South-Eastern Europe: distributional patterns and range size.

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    Nikolić, Toni; Mitić, Božena; Milašinović, Boris; Jelaska, Sven D

    2013-02-01

    During the analysis of alien and invasive flora of Europe, as a threat to biodiversity, data for Croatia were missing. The aim of our research was to analyse distributional patterns and range size of all invasive alien plants (64) for the state area (57,000 km(2)). They were detected on 49% of the state territory, averaging five taxa per 35 km(2). The greatest number of invasive plants (>30 per grid cell) was recorded in the major urban centres, increasing in the south-east direction and reflecting positive correlation with temperature and negative with altitude. The most endangered areas are in the Mediterranean region, especially on islands. The number of invasive plants increased with habitat diversity and almost 75% of all sites with invasive plants are located within a few habitats with direct anthropogenic influence. The results should provide a reliable regional and global basis for strategic planning regarding invasive alien plants management. Copyright © 2013 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  18. The invasive wetland plant Alternanthera philoxeroides shows a higher tolerance to waterlogging than its native Congener Alternanthera sessilis.

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    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.

  19. Strong response of an invasive plant species (Centaurea solstitialis L.) to global environmental changes.

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    Dukes, Jeffrey S; Chiariello, Nona R; Loarie, Scott R; Field, Christopher B

    2011-09-01

    Global environmental changes are altering interactions among plant species, sometimes favoring invasive species. Here, we examine how a suite of five environmental factors, singly and in combination, can affect the success of a highly invasive plant. We introduced Centaurea solstitialis L. (yellow starthistle), which is considered by many to be California's most troublesome wildland weed, to grassland plots in the San Francisco Bay Area. These plots experienced ambient or elevated levels of warming, atmospheric CO2, precipitation, and nitrate deposition, and an accidental fire in the previous year created an additional treatment. Centaurea grew more than six times larger in response to elevated CO2, and, outside of the burned area, grew more than three times larger in response to nitrate deposition. In contrast, resident plants in the community responded less strongly (or did not respond) to these treatments. Interactive effects among treatments were rarely significant. Results from a parallel mesocosm experiment, while less dramatic, supported the pattern of results observed in the field. Taken together, our results suggest that ongoing environmental changes may dramatically increase Centaurea's prevalence in western North America.

  20. Amorpha fruticosa – A Noxious Invasive Alien Plant in Europe or a Medicinal Plant against Metabolic Disease?

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    Ekaterina Kozuharova

    2017-06-01

    Full Text Available Amorpha fruticosa L. (Fabaceae is a shrub native to North America which has been cultivated mainly for its ornamental features, honey plant value and protective properties against soil erosion. It is registered amongst the most noxious invasive species in Europe. However, a growing body of scientific literature also points to the therapeutic potential of its chemical constituents. Due to the fact that A. fruticosa is an aggressive invasive species, it can provide an abundant and cheap resource of plant chemical constituents which can be utilized for therapeutic purposes. Additionally, exploitation of the biomass for medicinal use might contribute to relieving the destructive impact of this species on natural habitats. The aim of this review is to provide a comprehensive summary and systematize the state-of-the-art in the knowledge of the phytochemical composition and the potential of A. fruticosa in disease treatment and prevention, with especial emphasis on diabetes and metabolic syndrome. Also reviewed are aspects related to potential toxicity of A. fruticosa which has not yet been systematically evaluated in human subjects.

  1. 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

  2. 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.

    2012-01-01

    Background 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. Scope and Conclusions 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

  3. 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.

  4. An invasive clonal plant benefits from clonal integration more than a co-occurring native plant in nutrient-patchy and competitive environments.

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    You, Wenhua; Fan, Shufeng; Yu, Dan; Xie, Dong; Liu, Chunhua

    2014-01-01

    Many notorious invasive plants are clonal, however, little is known about the different roles of clonal integration effects between invasive and native plants. Here, we hypothesize that clonal integration affect growth, photosynthetic performance, biomass allocation and thus competitive ability of invasive and native clonal plants, and invasive clonal plants benefit from clonal integration more than co-occurring native plants in heterogeneous habitats. To test these hypotheses, two stoloniferous clonal plants, Alternanthera philoxeroides (invasive), Jussiaea repens (native) were studied in China. The apical parts of both species were grown either with or without neighboring vegetation and the basal parts without competitors were in nutrient- rich or -poor habitats, with stolon connections were either severed or kept intact. Competition significantly reduced growth and photosynthetic performance of the apical ramets in both species, but not the biomass of neighboring vegetation. Without competition, clonal integration greatly improved the growth and photosynthetic performance of both species, especially when the basal parts were in nutrient-rich habitats. When grown with neighboring vegetation, growth of J. repens and photosynthetic performance of both species were significantly enhanced by clonal integration with the basal parts in both nutrient-rich and -poor habitats, while growth and relative neighbor effect (RNE) of A. philoxeroides were greatly improved by clonal integration only when the basal parts were in nutrient-rich habitats. Moreover, clonal integration increased A. philoxeroides's biomass allocation to roots without competition, but decreased it with competition, especially when the basal ramets were in nutrient-rich sections. Effects of clonal integration on biomass allocation of J. repens was similar to that of A. philoxeroides but with less significance. These results supported our hypothesis that invasive clonal plants A. philoxeroides benefits

  5. An invasive clonal plant benefits from clonal integration more than a co-occurring native plant in nutrient-patchy and competitive environments.

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    Wenhua You

    Full Text Available Many notorious invasive plants are clonal, however, little is known about the different roles of clonal integration effects between invasive and native plants. Here, we hypothesize that clonal integration affect growth, photosynthetic performance, biomass allocation and thus competitive ability of invasive and native clonal plants, and invasive clonal plants benefit from clonal integration more than co-occurring native plants in heterogeneous habitats. To test these hypotheses, two stoloniferous clonal plants, Alternanthera philoxeroides (invasive, Jussiaea repens (native were studied in China. The apical parts of both species were grown either with or without neighboring vegetation and the basal parts without competitors were in nutrient- rich or -poor habitats, with stolon connections were either severed or kept intact. Competition significantly reduced growth and photosynthetic performance of the apical ramets in both species, but not the biomass of neighboring vegetation. Without competition, clonal integration greatly improved the growth and photosynthetic performance of both species, especially when the basal parts were in nutrient-rich habitats. When grown with neighboring vegetation, growth of J. repens and photosynthetic performance of both species were significantly enhanced by clonal integration with the basal parts in both nutrient-rich and -poor habitats, while growth and relative neighbor effect (RNE of A. philoxeroides were greatly improved by clonal integration only when the basal parts were in nutrient-rich habitats. Moreover, clonal integration increased A. philoxeroides's biomass allocation to roots without competition, but decreased it with competition, especially when the basal ramets were in nutrient-rich sections. Effects of clonal integration on biomass allocation of J. repens was similar to that of A. philoxeroides but with less significance. These results supported our hypothesis that invasive clonal plants A

  6. 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.

  7. Recruitment of invasive plant species in the Sundarbans following tropical Cyclone Aila

    Science.gov (United States)

    Rahman, M. M.; Vacik, H.

    2016-02-01

    The Sundarbans is the largest mangrove forest in the world. Two-thirds of the forest (62%) is in the southwest corner of Bangladesh while the rest is in the West Bengal of India. The out flow of water from Bangladesh is the third highest in the world, next to the Amazonia and Congo basin. Major rivers of Bangladesh flow from north to south, silting up the mangroves delta and draining into the Bay of Bengal. The mangroves delta is also a region of transition between the freshwater of the rivers originating from the Ganges and the saline water of the Bay of Bengal. The ecosystems as well as the luxuriant biodiversity of Sundarbans have strong interactions with marine environments. The environmental parameters with the direct influences on Sundarbans in terms of global climate change are sea-level rise, natural calamities like cyclones, salinity and drought. Almost 26 percent frequency of cyclones was increased over past 120 years in the Bay of Bengal. Five disastrous tropical cyclones originated in the Bay of Bengal since 2006 - Sidr, Nargis, Bijli, Aila and Mahasen. Cyclones impact Sundarbans through four primary mechanisms: wind damage, storm surge, sedimentation and colonization of invasive species. Many researches were carried out to investigate the wind damages. The invasions of plant species were not documented; this study is the first attempt to do so in a scientific manner. The study area in the Chandpai Range of Sundarbans was classified as `less affected' (LAA) and `high affected' (HAA) areas due to the tropical cyclone `Aila'. In total 23 invasive plant species were identified in the Chandpai Range of Sundarbans, out of them 19 species are indigenous and the rest are alien. All species were found in the HAA, where only 09 species were found in the LAA. The abundance, diversity and rate of invasion were higher in the HAA than that of LAA. Proper management must be adopted to control the invasion to protect the endemic species. Key words: Mangrove, Marine

  8. Invasive vascular plant species of oxbow lakes in south-western Poland

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    Spałek Krzysztof

    2015-06-01

    Full Text Available Natural water reservoirs are very valuable floristic sites in south-western Poland. Among them, the most important for the preservation of biodiversity of flora are oxbow lakes. The long-term process of human pressure on habitats of this type caused disturbances of their biological balance. Changes in the water regime, industrial development and chemisation of agriculture, especially in the period of the last two hundred years, led to systematic disappearances of localities of many plant species connected with rare habitats and also to the appearance of numerous invasive plant species. They are: Azolla filiculoides, Echinocystis lobata, Erechtites hieraciifolia, Impatiens glandulifera, I. parviflora, Reynoutria japonica, Solidago canadensis, S. gigantea and S. graminifolia. Field works were conducted in years 2005-2012.

  9. Timing Is Important: Unmanned Aircraft vs. Satellite Imagery in Plant Invasion Monitoring

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    Jana Müllerová

    2017-05-01

    Full Text Available The rapid spread of invasive plants makes their management increasingly difficult. Remote sensing offers a means of fast and efficient monitoring, but still the optimal methodologies remain to be defined. The seasonal dynamics and spectral characteristics of the target invasive species are important factors, since, at certain time of the vegetation season (e.g., at flowering or senescing, plants are often more distinct (or more visible beneath the canopy. Our aim was to establish fast, repeatable and a cost-efficient, computer-assisted method applicable over larger areas, to reduce the costs of extensive field campaigns. To achieve this goal, we examined how the timing of monitoring affects the detection of noxious plant invaders in Central Europe, using two model herbaceous species with markedly different phenological, structural, and spectral characteristics. They are giant hogweed (Heracleum mantegazzianum, a species with very distinct flowering phase, and the less distinct knotweeds (Fallopia japonica, F. sachalinensis, and their hybrid F. × bohemica. The variety of data generated, such as imagery from purposely-designed, unmanned aircraft vehicle (UAV, and VHR satellite, and aerial color orthophotos enabled us to assess the effects of spectral, spatial, and temporal resolution (i.e., the target species' phenological state for successful recognition. The demands for both spatial and spectral resolution depended largely on the target plant species. In the case that a species was sampled at the most distinct phenological phase, high accuracy was achieved even with lower spectral resolution of our low-cost UAV. This demonstrates that proper timing can to some extent compensate for the lower spectral resolution. The results of our study could serve as a basis for identifying priorities for management, targeted at localities with the greatest risk of invasive species' spread and, once eradicated, to monitor over time any return. The best mapping

  10. AM and DSE colonization of invasive plants in urban habitat: a study of Upper Silesia (southern Poland).

    Science.gov (United States)

    Gucwa-Przepióra, Ewa; Chmura, Damian; Sokołowska, Kamila

    2016-07-01

    Interactions between invasive plants and root endophytes may contribute to the exploration of plant invasion causes. Twenty plant species of alien origin differing in invasiveness were studied in terms of status and typical structures of arbuscular mycorrhizal fungi and dark septate endophytes (DSE) in urban habitats in Silesia Upland (southern Poland). We observed that 75 % of investigated plant species were mycorrhizal. The arbuscular mycorrhiza (AM) of most plant species was of the Arum morphology. The nearly 100 % mycorrhizal frequency, high intensity of AM colonization within root cortex and the presence of arbuscules in all mycorrhizal plant species indicate that the investigated species are able to establish AM associations in the secondary range and urban habitats. DSE were present in all mycorrhizal and non-mycorrhizal species. The frequency of DSE was significantly lower in non-mycorrhizal group of plants, however, sclerotia of DSE were found mainly in the roots of non-mycorrhizal plant species. The group of species native to North America including three Solidago congeners have the highest values of all AM mycorrhization and DSE indices. Moreover, we observed that most mycorrhizal invasive species belonged to the family Asteraceae. In turn, representatives of Poaceae had the lowest values of AM mycorrhization. Nevertheless, quite high values of DSE frequency were also encountered in roots of Poaceae species. The high invasiveness of the representatives of the Asteraceae family from North America support theory that both taxonomic pattern, and the fact of root endophytes colonization contribute to invasion success. While, the taxa of Reynoutria also represent successful invaders but they are of Asiatic origin, non-mycorrhizal and weakly colonized by DSE fungi.

  11. Edge Effects Influence the Abundance of the Invasive Halyomorpha halys (Hemiptera: Pentatomidae) in Woody Plant Nurseries.

    Science.gov (United States)

    Venugopal, P Dilip; Martinson, Holly M; Bergmann, Erik J; Shrewsbury, Paula M; Raupp, Michael J

    2015-06-01

    The invasive brown marmorated stink bug, Halyomorpha halys (Stål), has caused severe economic losses in the United States and is also a major nuisance pest invading homes. In diverse woody plant nurseries, favored host plants may be attacked at different times of the season and in different locations in the field. Knowledge of factors influencing H. halys abundance and simple methods to predict where H. halys are found and cause damage are needed to develop effective management strategies. In this study, we examined H. halys abundance on plants in tree nurseries as a function of distance from field edges (edge and core samples) and documented the abundance in tree nurseries adjoining different habitat types (corn, soybean, residential areas, and production sod). We conducted timed counts for H. halys on 2,016 individual trees belonging to 146 unique woody plant cultivars at two commercial tree nurseries in Maryland. Across three years of sampling, we found that H. halys nymphs and adults were more abundant at field edges (0-5 m from edges) than in the core of fields (15-20 m from edges). Proximity of soybean fields was associated with high nymph and adult abundance. Results indicate that monitoring efforts and intervention tactics for this invasive pest could be restricted to field edges, especially those close to soybean fields. We show clearly that spatial factors, especially distance from edge, strongly influence H. halys abundance in nurseries. This information may greatly simplify the development of any future management strategies. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

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    Steinbauer, Manuel J; Irl, Severin D H; González-Mancebo, Juana María; Breiner, Frank T; Hernández-Hernández, Raquel; Hopfenmüller, Sebastian; Kidane, Yohannes; Jentsch, Anke; Beierkuhnlein, Carl

    2017-01-01

    Ecosystems that provide environmental opportunities but are poor in species and functional richness generally support speciation as well as invasion processes. These processes are expected not to be equally effective along elevational gradients due to specific ecological, spatial, and anthropogenic filters, thus controlling the dispersal and establishment of species. Here, we investigate speciation and invasion processes along elevational gradients. We assess the vascular plant species richness as well as the number and percentage of endemic species and non-native species systematically along three elevational gradients covering large parts of the climatic range of La Palma, Canary Islands. Species richness was negatively correlated with elevation, while the percentage of Canary endemic species showed a positive relationship. However, the percentage of Canary-Madeira endemics did not show a relationship with elevation. Non-native species richness (indicating invasion) peaked at 500 m elevation and showed a consistent decline until about 1,200 m elevation. Above that limit, no non-native species were present in the studied elevational gradients. Ecological, anthropogenic, and spatial filters control richness, diversification, and invasion with elevation. With increase in elevation, richness decreases due to species-area relationships. Ecological limitations of native ruderal species related to anthropogenic pressure are in line with the absence of non-native species from high elevations indicating directional ecological filtering. Increase in ecological isolation with elevation drives diversification and thus increased percentages of Canary endemics. The best preserved eastern transect, including mature laurel forests, is an exception. The high percentage of Canary-Madeira endemics indicates the cloud forest's environmental uniqueness-and thus ecological isolation-beyond the Macaronesian islands.

  13. Evaluating Hypotheses of Plant Species Invasions on Mediterranean Islands: Inverse Patterns between Alien and Endemic Species

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    Alexander Bjarnason

    2017-08-01

    Full Text Available Invasive alien species cause major changes to ecosystem functioning and patterns of biodiversity, and the main factors involved in invasion success remain contested. Using the Mediterranean island of Crete, Greece as a case study, we suggest a framework for analyzing spatial data of alien species distributions, based on environmental predictors, aiming to gain an understanding of their spatial patterns and spread. Mediterranean islands are under strong ecological pressure from invading species due to their restricted size and increased human impact. Four hypotheses of invasibility, the “propagule pressure hypothesis” (H1, “biotic resistance hypothesis vs. acceptance hypothesis” (H2, “disturbance-mediated hypothesis” (H3, and “environmental heterogeneity hypothesis” (H4 were tested. Using data from alien, native, and endemic vascular plant species, the propagule pressure, biotic resistance vs. acceptance, disturbance-mediated, and environmental heterogeneity hypotheses were tested with Generalized Additive Modeling (GAM of 39 models. Based on model selection, the optimal model includes the positive covariates of native species richness, the negative covariates of endemic species richness, and land area. Variance partitioning between the four hypotheses indicated that the biotic resistance vs. acceptance hypothesis explained the vast majority of the total variance. These results show that areas of high species richness have greater invasibility and support the acceptance hypothesis and “rich-get-richer” distribution of alien species. The negative correlation between alien and endemic species appears to be predominantly driven by altitude, with fewer alien and more endemic species at greater altitudes, and habitat richness. The negative relationship between alien and endemic species richness provides potential for understanding patterns of endemic and alien species on islands, contributing to more effective conservation

  14. Non-invasive analysis of water and carbon transport and plant growth by nuclear magnetic resonance and positron emission tomography

    International Nuclear Information System (INIS)

    Schurr, U.; Bluemler, P.; Jahnke, S.; Roeb, G.; Minchin, P.; Lindenmair, J.; Fuellner, K.; Ziemons, K.

    2005-01-01

    Full text: Plant growth and transport processes are highly dynamic. They are characterized by plant-internal control processes and by strong interactions with the spatially and temporally varying environment. Analysis of structure-function relations of growth and transport in plants will strongly benefit from the development of non-invasive techniques. The paper will describe recent advances in the low and high-field NMR imaging of plant transport in xylem and phloem as well as on root growth analysis in artificial soils. Non-invasive functional analysis of the dynamics of carbon transport is possible by using the short-lived isotope 11 C. In addition to standard detection techniques, the recently developed positron emission tomography system for plants (PlanTIS) allows imaging the flow of 11 C-labelled compounds in two and three dimensions. These techniques will provide a real insight into the dynamic nature of growth and transport processes of plants in variable environments. (author)

  15. 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

    Background and Aims 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. Methods 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. Key Results 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. Conclusions 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

  16. Invasive plant species and their disaster-effects in dry tropical forests and rangelands of Kenya and Tanzania

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    John F. Obiri

    2011-04-01

    Full Text Available Invasive plants are a hazard in the tropical dry forests and rangelands of East Africa. Although often not reported, they have increasingly created disasters that have affected the environment and socio-economic wellbeing of communities inhabiting these dry regions. This paper reports on the key invasives in the drylands of Kenya and Tanzania and their effects, and suggests some disaster risk reduction (DRR strategies. The study was largely based on secondary data analysis and supported by surveys in the affected drylands. The findings show ten key invasive plant species that affect the drylands. Their disaster-effects vary and include: causing the death of livestock by poisoning and destroying livestock foliage, accelerating biodiversity loss via suppression of native plants, to increasing diseases by o#ering a breeding ground for mosquitoes and other insects that carry ailments like nagana and sleeping sickness. The DRR initiatives include (1 having a prudent land use system that discourages activities like unplanned burning of drylands, (2 assessing and monitoring phytosanitary risks associated with introduced plant species, (3 strengthening national and local institutional capacities that enhance invasive species awareness and preparedness for disasters, and (4 enhancing early warning systems related to plant invasion.

  17. Drought-Stressed Tomato Plants Trigger Bottom-Up Effects on the Invasive Tetranychus evansi.

    Science.gov (United States)

    Ximénez-Embún, Miguel G; Ortego, Félix; Castañera, Pedro

    2016-01-01

    Climate change will bring more drought periods that will have an impact on the irrigation practices of some crops like tomato, from standard water regime to deficit irrigation. This will promote changes in plant metabolism and alter their interactions with biotic stressors. We have tested if mild or moderate drought-stressed tomato plants (simulating deficit irrigation) have an effect on the biological traits of the invasive tomato red spider mite, Tetranychus evansi. Our data reveal that T evansi caused more leaf damage to drought-stressed tomato plants (≥1.5 fold for both drought scenarios). Mite performance was also enhanced, as revealed by significant increases of eggs laid (≥2 fold) at 4 days post infestation (dpi), and of mobile forms (≥2 fold and 1.5 fold for moderate and mild drought, respectively) at 10 dpi. The levels of several essential amino acids (histidine, isoleucine, leucine, tyrosine, valine) and free sugars in tomato leaves were significantly induced by drought in combination with mites. The non-essential amino acid proline was also strongly induced, stimulating mite feeding and egg laying when added to tomato leaf disks at levels equivalent to that estimated on drought-infested tomato plants at 10 dpi. Tomato plant defense proteins were also affected by drought and/or mite infestation, but T. evansi was capable of circumventing their potential adverse effects. Altogether, our data indicate that significant increases of available free sugars and essential amino acids, jointly with their phagostimulant effect, created a favorable environment for a better T. evansi performance on drought-stressed tomato leaves. Thus, drought-stressed tomato plants, even at mild levels, may be more prone to T evansi outbreaks in a climate change scenario, which might negatively affect tomato production on area-wide scales.

  18. Drought-Stressed Tomato Plants Trigger Bottom-Up Effects on the Invasive Tetranychus evansi.

    Directory of Open Access Journals (Sweden)

    Miguel G Ximénez-Embún

    Full Text Available Climate change will bring more drought periods that will have an impact on the irrigation practices of some crops like tomato, from standard water regime to deficit irrigation. This will promote changes in plant metabolism and alter their interactions with biotic stressors. We have tested if mild or moderate drought-stressed tomato plants (simulating deficit irrigation have an effect on the biological traits of the invasive tomato red spider mite, Tetranychus evansi. Our data reveal that T evansi caused more leaf damage to drought-stressed tomato plants (≥1.5 fold for both drought scenarios. Mite performance was also enhanced, as revealed by significant increases of eggs laid (≥2 fold at 4 days post infestation (dpi, and of mobile forms (≥2 fold and 1.5 fold for moderate and mild drought, respectively at 10 dpi. The levels of several essential amino acids (histidine, isoleucine, leucine, tyrosine, valine and free sugars in tomato leaves were significantly induced by drought in combination with mites. The non-essential amino acid proline was also strongly induced, stimulating mite feeding and egg laying when added to tomato leaf disks at levels equivalent to that estimated on drought-infested tomato plants at 10 dpi. Tomato plant defense proteins were also affected by drought and/or mite infestation, but T. evansi was capable of circumventing their potential adverse effects. Altogether, our data indicate that significant increases of available free sugars and essential amino acids, jointly with their phagostimulant effect, created a favorable environment for a better T. evansi performance on drought-stressed tomato leaves. Thus, drought-stressed tomato plants, even at mild levels, may be more prone to T evansi outbreaks in a climate change scenario, which might negatively affect tomato production on area-wide scales.

  19. Activity of components of the antioxidant system in the roots of potato plants at short-term temperature drop and invasion with parasitic nematodes.

    Science.gov (United States)

    Lavrova, V V; Matveeva, E M; Zinovieva, S V

    2017-09-01

    The activity of catalase and superoxide dismutase in the roots of susceptible plants and plants exposed to alternating temperatures, which were infected with the phytoparasitic nematode G. rostochiensis, was studied. It was found that, throughout the invasion period, the plants susceptible to invasion exhibited a high activity of these enzymes, which allowed them to maintain an active defense against the oxidative stress caused by the invasion and subsequent life activity of larvae. For the plants exposed to alternating temperatures, a decrease in the activity of catalase and superoxide dismutase at the early stages of invasion and an increase in the activity of these enzymes at the later stages was detected.

  20. Educational outreach and impacts of white-tailed deer browse on native and invasive plants at the Crooked Creek Environmental Learning Center, Armstrong County, Pennsylvania

    Science.gov (United States)

    Lindsay, Lisa O.

    Overabundance of deer can assist the intrusion of invasive plants through browse, leading to homogenization of plant communities. Public attitudes towards native and invasive plant species and white-tailed deer browse related to personal experiences, can be changed through education focusing public awareness of ramifications of deer browse on native and invasive plants. I developed an interactive, interpretive Self-Guided Walking Tour brochure of the "You Can Trail" to provide an educational outreach program for visitors of Crooked Creek Environmental Learning Center that includes ecologically important native and invasive plants species from my investigation. This research study focuses on the overall abundance of native and invasive plant species once Odocoileus virginianus have been removed from the landscape during collection periods in June and September 2013 from exclosure and access plots that were maintained for seven years. Similarity of abundance were found in native and invasive abundance of forbs, bushes and percentage of ground cover. Differences included native bush volume being greater than invasive bush volume in the access plot in June with opposing results in the exclosure plot, being greater in invasive bush volume. However, in September, native and invasive bush volume was similar within the exclosure plot, while invasive bush volume decreased in the access plot. Invasive vines recorded in the June access plot were absent in the September collection period.

  1. Evidence, Perceptions, and Trade-offs Associated with Invasive Alien Plant Control in the Table Mountain National Park, South Africa

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    Brian W. van Wilgen

    2012-06-01

    Full Text Available The Table Mountain National Park is a 265 km2 protected area embedded within a city of 3.5 million people. The park contains an extremely diverse flora with many endemic species, and has been granted World Heritage Site status in recognition of this unique biodiversity. Invasive alien plants are arguably the most significant threat to the conservation of this biodiversity, and the past decade has seen the implementation of aggressive programs aimed at the removal of invasions by these plants. These invasive alien plants include several species of trees, notably pines (Pinus species and eucalypts (Eucalyptus species, which historically have been grown in plantations, and which are utilized for recreation by the city's residents. In addition, many 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 operations and the scientific rationale for their implementation, and the concerns that have been raised about the operations. Evidence in support of control includes the aggressive invasive nature of many species, and the fact that they displace native biodiversity (often irreversibly and have negative impacts on hydrology, fire intensity, and soil stability. Those against control cite aesthetic concerns, the value of pine plantations for recreation, the (perceived unattractive nature of the treeless natural vegetation, and the (incorrect belief that trees bring additional rainfall. The debate has been conducted through the press, and examples of perceptions and official responses are given. Despite opposition, the policy promoting alien plant removal has remained in place, and considerable progress has been made towards clearing pine plantations and invasive populations. This conservation success story owes much to political support, arising largely from job

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

    Science.gov (United States)

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

    2017-08-01

    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 interactions of invasive and native species and their combined effects on river dynamics is essential for developing cost-effective management strategies. However, numerical models for simulating long-term effects of these processes are lacking. This paper investigates how an invasive alien plant species affects native riparian vegetation and hydro-morphodynamics. A morphodynamic model has been coupled to a dynamic vegetation model that predicts establishment, growth and mortality of riparian trees. We introduced an invasive alien species with life-history traits based on Japanese Knotweed (Fallopia japonica), and investigated effects of low- and high propagule pressure on invasion speed, native vegetation and hydro-morphodynamic processes. Results show that high propagule pressure leads to a decline in native species cover due to competition and the creation of unfavorable native colonization sites. With low propagule pressure the invader facilitates native seedling survival by creating favorable hydro-morphodynamic conditions at colonization sites. With high invader abundance, water levels are raised and sediment transport is reduced during the growing season. In winter, when the above-ground invader biomass is gone, results are reversed and the floodplain is more prone to erosion. Invasion effects thus depend on seasonal above- and below ground dynamic vegetation properties and persistence of the invader, on the characteristics of native species it replaces, and the combined interactions with hydro-morphodynamics.

  3. Plastic responses of native plant root systems to the presence of an invasive annual grass.

    Science.gov (United States)

    Phillips, Allison J; Leger, Elizabeth A

    2015-01-01

    • The ability to respond to environmental change via phenotypic plasticity may be important for plants experiencing disturbances such as climate change and plant invasion. Responding to belowground competition through root plasticity may allow native plants to persist in highly invaded systems such as the cold deserts of the Intermountain West, USA.• We investigated whether Poa secunda, a native bunchgrass, could alter root morphology in response to nutrient availability and the presence of a competitive annual grass. Seeds from 20 families were grown with high and low nutrients and harvested after 50 d, and seeds from 48 families, grown with and without Bromus tectorum, were harvested after ∼2 or 6 mo. We measured total biomass, root mass fraction, specific root length (SRL), root tips, allocation to roots of varying diameter, and plasticity in allocation.• Plants had many parallel responses to low nutrients and competition, including increased root tip production, a trait associated with tolerance to reduced resources, though families differed in almost every trait and correlations among trait changes varied among experiments, indicating flexibility in plant responses. Seedlings actively increased SRL and fine root allocation under competition, while older seedlings also increased coarse root allocation, a trait associated with increased tolerance, and increased root mass fraction.• The high degree of genetic variation for root plasticity within natural populations could aid in the long-term persistence of P. secunda because phenotypic plasticity may allow native species to persist in invaded and fluctuating resource environments. © 2015 Botanical Society of America, Inc.

  4. Invasive giant hogweeds in Poland: Risk of burns among forestry workers and plant distribution.

    Science.gov (United States)

    Rzymski, Piotr; Klimaszyk, Piotr; Poniedziałek, Barbara

    2015-12-01

    The Caucasian giant hogweeds (Heracleum sosnowskyi Manden. and Heracleum mantegazzianum Sommier et Lever) are aggressive invaders that are successfully spreading in different parts of the world. Exposure of human skin to these plants may lead to phototoxicity and even chemical burns manifested by cutaneous, full-thickness, and long-lasting dermatitis, and in extreme cases, massive skin necrosis. Forestry workers are a group with potentially increased risk of exposure to these plants because of the outdoor nature of their work and their active involvement in managing invasive species. Therefore, in this study, we aimed at investigating their level of awareness with regard to the giant hogweeds in Poland. The morphology of the plants, health threats, treatment, and control methods were all considered. We also evaluated the distribution of these plants within forest districts in Poland. For this reason, we surveyed 1563 employees (forest rangers, manual workers, and administration staff) of the State Forests National Forest Holding in Poland "State Forests," working in 367 different forest districts. It was initially found that the forestry workers were generally aware of the giant hogweeds' morphology and phototoxicity. More than 20% of the surveyed individuals had been exposed to these plants at least once in their lives, but only less than half of them were aware of proceeding afterward. At the same time, <35% of those surveyed had any knowledge of the control and management of these giant hogweeds. As demonstrated by our study, stands of these species are widely distributed within the Polish forest districts (reported in over 50%). Therefore, there is an urgent need to implement an efficient, multistrategic, and long-term approach to both control their spread and protect human health. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

  5. Predictors, spatial distribution, and occurrence of woody invasive plants in subtropical urban ecosystems.

    Science.gov (United States)

    Staudhammer, Christina L; Escobedo, Francisco J; Holt, Nathan; Young, Linda J; Brandeis, Thomas J; Zipperer, Wayne

    2015-05-15

    We examined the spatial distribution, occurrence, and socioecological predictors of woody invasive plants (WIP) in two subtropical, coastal urban ecosystems: San Juan, Puerto Rico and Miami-Dade, United States. These two cities have similar climates and ecosystems typical of subtropical regions but differ in socioeconomics, topography, and urbanization processes. Using permanent plot data, available forest inventory protocols and statistical analyses of geographic and socioeconomic spatial predictors, we found that landscape level distribution and occurrence of WIPs was not clustered. We also characterized WIP composition and occurrence using logistic models, and found they were strongly related to the proportional area of residential land uses. However, the magnitude and trend of increase depended on median household income and grass cover. In San Juan, WIP occurrence was higher in areas of high residential cover when incomes were low or grass cover was low, whereas the opposite was true in Miami-Dade. Although Miami-Dade had greater invasive shrub cover and numbers of WIP species, San Juan had far greater invasive tree density, basal area and crown cover. This study provides an approach for incorporating field and available census data in geospatial distribution models of WIPs in cities throughout the globe. Findings indicate that identifying spatial predictors of WIPs depends on site-specific factors and the ecological scale of the predictor. Thus, mapping protocols and policies to eradicate urban WIPs should target indicators of a relevant scale specific to the area of interest for their improved and proactive management. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Phenotypic plasticity influences the size, shape and dynamics of the geographic distribution of an invasive plant.

    Directory of Open Access Journals (Sweden)

    Jean-Baptiste Pichancourt

    Full Text Available Phenotypic plasticity has long been suspected to allow invasive species to expand their geographic range across large-scale environmental gradients. We tested this possibility in Australia using a continental scale survey of the invasive tree Parkinsonia aculeata (Fabaceae in twenty-three sites distributed across four climate regions and three habitat types. Using tree-level responses, we detected a trade-off between seed mass and seed number across the moisture gradient. Individual trees plastically and reversibly produced many small seeds at dry sites or years, and few big seeds at wet sites and years. Bigger seeds were positively correlated with higher seed and seedling survival rates. The trade-off, the relation between seed mass, seed and seedling survival, and other fitness components of the plant life-cycle were integrated within a matrix population model. The model confirms that the plastic response resulted in average fitness benefits across the life-cycle. Plasticity resulted in average fitness being positively maintained at the wet and dry range margins where extinction risks would otherwise have been high ("Jack-of-all-Trades" strategy JT, and fitness being maximized at the species range centre where extinction risks were already low ("Master-of-Some" strategy MS. The resulting hybrid "Jack-and-Master" strategy (JM broadened the geographic range and amplified average fitness in the range centre. Our study provides the first empirical evidence for a JM species. It also confirms mechanistically the importance of phenotypic plasticity in determining the size, the shape and the dynamic of a species distribution. The JM allows rapid and reversible phenotypic responses to new or changing moisture conditions at different scales, providing the species with definite advantages over genetic adaptation when invading diverse and variable environments. Furthermore, natural selection pressure acting on phenotypic plasticity is predicted to result

  7. Is Physiological Performance a Good Predictor for Fitness? Insights from an Invasive Plant Species

    Science.gov (United States)

    Molina-Montenegro, Marco A.; Salgado-Luarte, Cristian; Oses, Rómulo; Torres-Díaz, Cristian

    2013-01-01

    Is physiological performance a suitable proxy of fitness in plants? Although, several studies have been conducted to measure some fitness-related traits and physiological performance, direct assessments are seldom found in the literature. Here, we assessed the physiology-fitness relationship using second-generation individuals of the invasive plant species Taraxacum officinale from 17 localities distributed in five continents. Specifically, we tested if i) the maximum quantum yield is a good predictor for seed-output ii) whether this physiology-fitness relationship can be modified by environmental heterogeneity, and iii) if this relationship has an adaptive consequence for T. officinale individuals from different localities. Overall, we found a significant positive relationship between the maximum quantum yield and fitness for all localities evaluated, but this relationship decreased in T. officinale individuals from localities with greater environmental heterogeneity. Finally, we found that those individuals from localities where environmental conditions are highly seasonal performed better under heterogeneous environmental conditions. Contrarily, under homogeneous controlled conditions, those individuals from localities with low environmental seasonality performed much better. In conclusion, our results suggest that the maximum quantum yield seem to be good predictors for plant fitness. We suggest that rapid measurements, such as those obtained from the maximum quantum yield, could provide a straightforward proxy of individual’s fitness in changing environments. PMID:24204626

  8. Lusus naturae:climate and invasions of plant pathogens modify agricultural and forest lands

    Directory of Open Access Journals (Sweden)

    Alessandro Ragazzi

    2009-10-01

    Full Text Available The ecological and economic sustainability of agricultural and forest systems of many advanced and underdeveloped Countries are strongly threatened by the increasing introduction of exotic plant pathogens. This article provides an overview of the main causes behind these invasions. Some important diseases caused by non native phytopathogens, whose arrival in the past century had a disastrous impact on the environment and economy of vast rural areas of our Country are reported. Some dangerous, emerging pathogens, which are literally destroying whole territories in various parts of the Planet, with severe damage to agricultural crops, landscape, economy and local tourism are also reported. Action strategies to prevent immigration of unwanted pathogens, and mitigation strategies, aimed at the development of various measures to mitigate the negative effects of plant parasites already established in the territory are then discussed. Finally, it is highlighted how such a far-reaching problem can be properly tackled only with the active contribution of governments, institutions responsible for plant health monitoring (warning services, research, and agricultural, tourism and transport operators.

  9. Is physiological performance a good predictor for fitness? Insights from an invasive plant species.

    Directory of Open Access Journals (Sweden)

    Marco A Molina-Montenegro

    Full Text Available Is physiological performance a suitable proxy of fitness in plants? Although, several studies have been conducted to measure some fitness-related traits and physiological performance, direct assessments are seldom found in the literature. Here, we assessed the physiology-fitness relationship using second-generation individuals of the invasive plant species Taraxacum officinale from 17 localities distributed in five continents. Specifically, we tested if i the maximum quantum yield is a good predictor for seed-output ii whether this physiology-fitness relationship can be modified by environmental heterogeneity, and iii if this relationship has an adaptive consequence for T. officinale individuals from different localities. Overall, we found a significant positive relationship between the maximum quantum yield and fitness for all localities evaluated, but this relationship decreased in T. officinale individuals from localities with greater environmental heterogeneity. Finally, we found that those individuals from localities where environmental conditions are highly seasonal performed better under heterogeneous environmental conditions. Contrarily, under homogeneous controlled conditions, those individuals from localities with low environmental seasonality performed much better. In conclusion, our results suggest that the maximum quantum yield seem to be good predictors for plant fitness. We suggest that rapid measurements, such as those obtained from the maximum quantum yield, could provide a straightforward proxy of individual's fitness in changing environments.

  10. 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

    2015-01-01

    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

  11. Temperature-dependent performance of competitive native and alien invasive plant species

    Science.gov (United States)

    Song, Uhram

    2017-10-01

    To assess the likely impacts of environmental change, the responses of two well-known invasive plant species, native Pueraria lobata and alien Humulus japonicus, to differences in growth temperature were studied in South Korea. Habitat preferences, physiological responses such as photosynthetic rates and chlorophyll contents, growth rates, and nutrient contents were quantified for each species. A competition experiment was conducted to evaluate the temperature preferences of the two species. All results indicated that the alien species H. japonicus can take advantage of elevated temperatures (35 °C) to enhance its competitive advantage against the native species P. lobata. While H. japonicus took advantage of elevated temperatures and preferred high-temperature areas, P. lobata showed reduced performance and dominance in high-temperature areas. Therefore, in future, due to global warming and urbanization, there are possibilities that H. japonicus takes advantage of elevated temperature against P. lobata that could lead to increased H. japonicus coverage over time. Therefore, consistent monitoring of both species especially where P. lobata is dominated are required because both species are found in every continents in the world. Controlling P. lobata requires thorough inspection of H. japonicus presence of the habitat in advance to prevent post P. lobata management invasion of H. japonicus.

  12. Biological invasion by Myrica faya in Hawaii: Plant demography, nitrogen fixation, ecosystem effects

    International Nuclear Information System (INIS)

    Vitousek, P.M.; Walker, L.R.

    1989-01-01

    Myrica faya, an introduced actinorhizal nitrogen fixer, in invading young volcanic sites in Hawaii Volcanoes National Park. We examined the population biology of the invader and ecosystem-level consequences of its invasion in open-canopied forests resulting from volcanic cinder-fall. Although Myrica faya is nominally dioecious, both males and females produce large amounts of fruit that are utilized by a number of exotic and native birds, particularly the exotic Zosterops japonica. In areas of active colonization, Myrica seed rain under perch trees of the dominant native Metrosideros polymorpha ranged from 6 to 60 seeds m -2 yr -1 ; no seeds were captured in the open. Planted seeds of Myrica also germinated an established better under isolated individuals of Metrosideros than in the open. Diameter growth of Myrica is > 15-fold greater than that of Metrosideros, and the Myrica population is increasing rapidly. Rates of nitrogen fixation were measured using the acetylene reduction assay calibrated with 15 N. Myrica nodules reduced acetylene at between 5 and 20 μmol g -1 h -1 , a rate that extrapolated to nitrogen fixation of 18 kg ha -1 in a densely colonized site. By comparison, all native sources of nitrogen fixation summed to 0.2 kg ha -1 yr -1 , and precipitation added -1 yr -1 . Measurements of litter decomposition and nitrogen release, soil nitrogen mineralization, and plant growth in bioassays all demonstrated that nitrogen fixed by Myrica becomes available to other organisms as well. We conclude that biological invasion by Myrica faya alters ecosystem-level properties in this young volcanic area; at least in this case, the demography and physiology of one species controls characteristics of a whole ecosystem

  13. Extra-regional residence time as a correlate of plant invasiveness: European archaeophytes in North America.

    Science.gov (United States)

    La Sorte, Frank A; Pysek, Petr

    2009-09-01

    Human activities have degraded biogeographical barriers to dispersal resulting in the spread and naturalization of increasing numbers of nonnative invasive species. One correlate of invasiveness within a region is residence time or time since introduction. Plant species that were introduced into Europe prior to AD 1500 (European archaeophytes) that were subsequently introduced into North America provide a unique opportunity to examine the effect of extra-regional residence time (i.e., residence time that occurred in a nonnative region before a species was introduced into a new region). Here, we examine how nonnative species with extensive extra-regional residence times have affected beta diversity among states in the contiguous United States of America based on an analysis of occupancy and distance decay of similarity. State floras contained an average of 3106 +/- 922 species (mean +/- SD) with 2318 +/- 757 species classified as native, 180 +/- 43 species as European archaeophyte, and 608 -236 species as other exotic with no European archaeophyte association. For European archaeophytes, 42% were identified as noxious weeds in the United States with 8% identified as agricultural and 14% as natural-area weeds (20%, 2%, and 13% for other exotics, respectively). In strong contrast to natives and other exotics, European archaeophytes were more widespread and presented weaker distance-decay patterns. Thus, European archaeophytes were more likely to become noxious weeds, particularly within agricultural areas, and were associated with significant losses in beta diversity. We suggest that this outcome is a consequence of extra-regional residence time, which allowed for the selection of species or the evolution of traits that favored the colonization of arable habitats associated with early agricultural activities in Europe, habitats that are widespread, resource rich, and uniformly distributed in the United States. Our findings suggest that a long-term trajectory can be

  14. Inventory of Invasive Plant Species along the corridor of Kawah Ijen Nature Tourism Park, Banyuwangi, East Java

    Directory of Open Access Journals (Sweden)

    Lia Hapsari

    2014-01-01

    Full Text Available A field survey was conducted in November 2013 to inventory invasive plant species present along the corridor of Kawah Ijen Nature Tourism Park exploratively. Result showed that there were 11 plant species found abundantly along the corridor. Typical native species were dominated by Cyathea contaminans, Casuarina junghuhniana and Vaccinium varingiaefolium. Three species were determined as invasive alien species i.e. Chromolaena odorata, Acacia decurrens and Blumea lacera whereas five species were determined as native species but potential invaders i.e. Rubus moluccanus, Melastoma malabatrichum, Polygonum barbatum, Debregeasia longifolia and Pteridium aquilinum. In term of tourism particularly on nature-based destinations enable moving in and out of invasive alien species due to opening the access of some natural protected areas. The environmental impact of an alien species whether it becomes invasive at its destination depends on its biological key point,  what ecological role the species may play, and on additional factors such as its tolerance of the gross features of the environment in the new range. Keyword: invasive plants, corridor, Kawah Ijen, Nature Tourism Park, Banyuwangi

  15. 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

  16. Local crop planting systems enhance insecticide-mediated displacement of two invasive leafminer fly.

    Directory of Open Access Journals (Sweden)

    Yulin Gao

    Full Text Available Liriomyza sativae and L. trifolii are highly invasive leafminer pests of vegetable crops that have invaded southern China in recent years. Liriomyza sativae was the first of these species to invade China, but it is now being displaced by L. trifolii. The rate and extent of this displacement vary across southern China. In Hainan, monocultures of highly valuable cowpea are planted and treated extensively with insecticides in attempts to control leafminer damage. In Guangdong, cowpea fields are interspersed with other less valuable crops, such as towel gourd (Luffa cylindrica, which receive significantly fewer insecticide applications than cowpea. To determine how differences in cropping systems influence the Liriomyza species composition, we conducted field trials in 2011 and 2012 in Guangdong where both species were present. We replicated conditions in Hainan by planting cowpea monocultures that were isolated from other agricultural fields, and we replicated conditions in Guangdong by planting cowpea in a mixed crop environment with towel gourd planted in neighboring plots. We then compared leafminer populations in cowpea treated with the insecticide avermectin and untreated cowpea. We also monitored leafminer populations in the untreated towel gourd. Untreated cowpea and towel gourd had comparatively low proportions of L. trifolii, which remained relatively stable over the course of each season. Avermectin applications led to increases in the proportions of L. trifolii, and after three weekly applications populations were >95% L. trifolii in both crop systems. However, the rate of change and persistence of L. trifolii in the mixed crop system were less than in the monocrop. These results indicate that L. trifolii is much less susceptible to avermectin than is L. sativae. Further, L. sativae was able to persist in the untreated towel gourd, which probably enabled it to recolonize treated cowpea.

  17. An Invasive Plant Promotes Its Arbuscular Mycorrhizal Symbioses and Competitiveness through Its Secondary Metabolites: Indirect Evidence from Activated Carbon

    Science.gov (United States)

    Yuan, Yongge; Tang, Jianjun; Leng, Dong; Hu, Shuijin; Yong, Jean W. H.; Chen, Xin

    2014-01-01

    Secondary metabolites released by invasive plants can increase their competitive ability by affecting native plants, herbivores, and pathogens at the invaded land. Whether these secondary metabolites affect the invasive plant itself, directly or indirectly through microorganisms, however, has not been well documented. Here we tested whether activated carbon (AC), a well-known absorbent for secondary metabolites, affect arbuscular mycorrhizal (AM) symbioses and competitive ability in an invasive plant. We conducted three experiments (experiments 1–3) with the invasive forb Solidago canadensis and the native Kummerowia striata. Experiment 1 determined whether AC altered soil properties, levels of the main secondary metabolites in the soil, plant growth, and AMF communities associated with S. canadensis and K. striata. Experiment 2 determined whether AC affected colonization of S. canadensis by five AMF, which were added to sterilized soil. Experiment 3 determined the competitive ability of S. canadensis in the presence and absence of AMF and AC. In experiment 1, AC greatly decreased the concentrations of the main secondary metabolites in soil, and the changes in concentrations were closely related with the changes of AMF in S. canadensis roots. In experiment 2, AC inhibited the AMF Glomus versiforme and G. geosporum but promoted G. mosseae and G. diaphanum in the soil and also in S. canadensis roots. In experiment 3, AC reduced S. canadensis competitive ability in the presence but not in the absence of AMF. Our results provided indirect evidence that the secondary metabolites (which can be absorbed by AC) of the invasive plant S. canadensis may promote S. canadensis competitiveness by enhancing its own AMF symbionts. PMID:24817325

  18. An invasive plant promotes its arbuscular mycorrhizal symbioses and competitiveness through its secondary metabolites: indirect evidence from activated carbon.

    Directory of Open Access Journals (Sweden)

    Yongge Yuan

    Full Text Available Secondary metabolites released by invasive plants can increase their competitive ability by affecting native plants, herbivores, and pathogens at the invaded land. Whether these secondary metabolites affect the invasive plant itself, directly or indirectly through microorganisms, however, has not been well documented. Here we tested whether activated carbon (AC, a well-known absorbent for secondary metabolites, affect arbuscular mycorrhizal (AM symbioses and competitive ability in an invasive plant. We conducted three experiments (experiments 1-3 with the invasive forb Solidago canadensis and the native Kummerowia striata. Experiment 1 determined whether AC altered soil properties, levels of the main secondary metabolites in the soil, plant growth, and AMF communities associated with S. canadensis and K. striata. Experiment 2 determined whether AC affected colonization of S. canadensis by five AMF, which were added to sterilized soil. Experiment 3 determined the competitive ability of S. canadensis in the presence and absence of AMF and AC. In experiment 1, AC greatly decreased the concentrations of the main secondary metabolites in soil, and the changes in concentrations were closely related with the changes of AMF in S. canadensis roots. In experiment 2, AC inhibited the AMF Glomus versiforme and G. geosporum but promoted G. mosseae and G. diaphanum in the soil and also in S. canadensis roots. In experiment 3, AC reduced S. canadensis competitive ability in the presence but not in the absence of AMF. Our results provided indirect evidence that the secondary metabolites (which can be absorbed by AC of the invasive plant S. canadensis may promote S. canadensis competitiveness by enhancing its own AMF symbionts.

  19. An invasive plant promotes its arbuscular mycorrhizal symbioses and competitiveness through its secondary metabolites: indirect evidence from activated carbon.

    Science.gov (United States)

    Yuan, Yongge; Tang, Jianjun; Leng, Dong; Hu, Shuijin; Yong, Jean W H; Chen, Xin

    2014-01-01

    Secondary metabolites released by invasive plants can increase their competitive ability by affecting native plants, herbivores, and pathogens at the invaded land. Whether these secondary metabolites affect the invasive plant itself, directly or indirectly through microorganisms, however, has not been well documented. Here we tested whether activated carbon (AC), a well-known absorbent for secondary metabolites, affect arbuscular mycorrhizal (AM) symbioses and competitive ability in an invasive plant. We conducted three experiments (experiments 1-3) with the invasive forb Solidago canadensis and the native Kummerowia striata. Experiment 1 determined whether AC altered soil properties, levels of the main secondary metabolites in the soil, plant growth, and AMF communities associated with S. canadensis and K. striata. Experiment 2 determined whether AC affected colonization of S. canadensis by five AMF, which were added to sterilized soil. Experiment 3 determined the competitive ability of S. canadensis in the presence and absence of AMF and AC. In experiment 1, AC greatly decreased the concentrations of the main secondary metabolites in soil, and the changes in concentrations were closely related with the changes of AMF in S. canadensis roots. In experiment 2, AC inhibited the AMF Glomus versiforme and G. geosporum but promoted G. mosseae and G. diaphanum in the soil and also in S. canadensis roots. In experiment 3, AC reduced S. canadensis competitive ability in the presence but not in the absence of AMF. Our results provided indirect evidence that the secondary metabolites (which can be absorbed by AC) of the invasive plant S. canadensis may promote S. canadensis competitiveness by enhancing its own AMF symbionts.

  20. 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 SO 4 2- to NO 3 - 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 SO 4 2- to NO 3 - 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 SO 4 2- to NO 3 - ratios tended to have more toxic effects on SNB likely due to the higher exchange capacity of hydroxyl groups (OH - ) between SO 4 2- and NO 3 - . 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.

  1. Plant competitive interactions and invasiveness: searching for the effects of phylogenetic relatedness and origin on competition intensity

    Czech Academy of Sciences Publication Activity Database

    Dostál, Petr

    2011-01-01

    Roč. 177, č. 5 (2011), s. 655-667 ISSN 0003-0147 R&D Projects: GA ČR GAP504/10/0132 Institutional research plan: CEZ:AV0Z60050516 Keywords : competitive equivalence * invasive plants * phylogenetic similarity Subject RIV: EF - Botanics Impact factor: 4.725, year: 2011

  2. Potential Alternatives to Classical Biocontrol: Using Native Agents in Invaded Habitats and Genetically Engineered Sterile Cultivars for Invasive Plant Management

    Science.gov (United States)

    ShiLi Miao; Yi Li; Qinfeng Guo; Hua Yu; JiangQing Ding; et al.

    2012-01-01

    The development of an effective approach to control and eradication of invasive species has become a major challenge to scientists, managers, and society. Biocontrol has been widely utilized to control exotic plants in the past few decades with some degree of sucess. However, there have been an increasing number of controversies pertaining to this approach, largely...

  3. 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...

  4. Catalogue of alien plants of the Czech Republic (2nd edition): checklist update, taxonomic diversity and invasion patterns

    Czech Academy of Sciences Publication Activity Database

    Pyšek, Petr; Danihelka, Jiří; Sádlo, Jiří; Chrtek, Jindřich; Chytrý, M.; Jarošík, Vojtěch; Kaplan, Zdeněk; Krahulec, František; Moravcová, Lenka; Pergl, Jan; Štajerová, Kateřina; Tichý, L.

    2012-01-01

    Roč. 84, č. 2 (2012), s. 155-255 ISSN 0032-7786 R&D Projects: GA ČR(CZ) GAP504/11/1028 Institutional support: RVO:67985939 Keywords : invasive plants * checklist * Czech Republic Subject RIV: EF - Botanics Impact factor: 2.833, year: 2012

  5. The role of symbiotic nitrogen fixation in nitrogen availability, competition and plant invasion into the sagebrush steppe

    Science.gov (United States)

    Erin M. Goergen

    2009-01-01

    In the semi-arid sagebrush steppe of the Northeastern Sierra Nevada, resources are both spatially and temporally variable, arguably making resource availability a primary factor determining invasion success. N fixing plant species, primarily native legumes, are often relatively abundant in sagebrush steppe and can contribute to ecosystem nitrogen budgets. ...

  6. Behavioral response of the invasive Halyomorpha halys (Hemiptera: Pentatomidae) to host plant stimuli augmented with semiochemicals in the field

    Science.gov (United States)

    While much work has focused on understanding how the invasive brown marmorated stink bug, or Halyomorpha halys, responds to pheromonal stimuli, very little work has explored the response of H. halys to plant volatiles and other host stimuli. The goals of the current study were to understand 1) whet...

  7. Ant predation on an invasive herbivore: Can an extrafloral nectar-producing plant provide associational resistance to Opuntia individuals?

    Science.gov (United States)

    The legume Chamaecrista fasciculata attracts ants to its extrafloral nectar (EFN) which can lead to reduced herbivory and increased fecundity for the plant. In Florida, Opuntia stricta and O. humifusa, hosts of the invasive moth Cactoblastis cactorum, are often found growing in close association wit...

  8. 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,

  9. Proposed classification of invasive alien plant species in South Africa: towards prioritizing species and areas for management action

    CSIR Research Space (South Africa)

    Nel, JL

    2004-01-01

    Full Text Available the objective derivation of two lists of invasive alien plants in South Africa, using available quantitative data and expert knowledge on current patterns of distribution and abundance, life-history traits, and (for emerging invaders) estimates of potential...

  10. Invasive plants have different effects on trophic structure of green and brown food webs in terrestrial ecosystems: a meta-analysis.

    Science.gov (United States)

    McCary, Matthew A; Mores, Robin; Farfan, Monica A; Wise, David H

    2016-03-01

    Although invasive plants are a major source of terrestrial ecosystem degradation worldwide, it remains unclear which trophic levels above the base of the food web are most vulnerable to plant invasions. We performed a meta-analysis of 38 independent studies from 32 papers to examine how invasive plants alter major groupings of primary and secondary consumers in three globally distributed ecosystems: wetlands, woodlands and grasslands. Within each ecosystem we examined if green (grazing) food webs are more sensitive to plant invasions compared to brown (detrital) food webs. Invasive plants have strong negative effects on primary consumers (detritivores, bacterivores, fungivores, and/or herbivores) in woodlands and wetlands, which become less abundant in both green and brown food webs in woodlands and green webs in wetlands. Plant invasions increased abundances of secondary consumers (predators and/or parasitoids) only in woodland brown food webs and green webs in wetlands. Effects of invasive plants on grazing and detrital food webs clearly differed between ecosystems. Overall, invasive plants had the most pronounced effects on the trophic structure of wetlands and woodlands, but caused no detectable changes to grassland trophic structure. © 2016 John Wiley & Sons Ltd/CNRS.

  11. Higher photosynthesis, nutrient- and energy-use efficiencies contribute to invasiveness of exotic plants in a nutrient poor habitat in northeast China.

    Science.gov (United States)

    Liu, Ming-Chao; Kong, De-Liang; Lu, Xiu-Rong; Huang, Kai; Wang, Shuo; Wang, Wei-Bin; Qu, Bo; Feng, Yu-Long

    2017-08-01

    The roles of photosynthesis-related traits in invasiveness of introduced plant species are still not well elucidated, especially in nutrient-poor habitats. In addition, little effort has been made to determine the physiological causes and consequences of the difference in these traits between invasive and native plants. To address these problems, we compared the differences in 16 leaf functional traits related to light-saturated photosynthetic rate (P max ) between 22 invasive and native plants in a nutrient-poor habitat in northeast China. The invasive plants had significantly higher P max , photosynthetic nitrogen- (PNUE), phosphorus- (PPUE), potassium- (PKUE) and energy-use efficiencies (PEUE) than the co-occurring natives, while leaf nutrient concentrations, construction cost (CC) and specific leaf area were not significantly different between the invasive and native plants. The higher PNUE contributed to higher P max for the invasive plants, which in turn contributed to higher PPUE, PKUE and PEUE. CC changed independently with other traits such as P max , PNUE, PPUE, PKUE and PEUE, showing two trait dimensions, which may facilitate acclimation to multifarious niche dimensions. Our results indicate that the invasive plants have a superior resource-use strategy, i.e. higher photosynthesis under similar resource investments, contributing to invasion success in the barren habitat. © 2017 Scandinavian Plant Physiology Society.

  12. Vulnerability of oak-dominated forests in West Virginia to invasive exotic plants: temporal and spatial patterns of nine exotic species using herbarium records and land classification data

    Science.gov (United States)

    Cynthia D. Huebner

    2003-01-01

    Are oak-dominated forests immune to invasive exotic plants? Herbarium and land classification data were used to evaluate the extent of spread of nine invasive exotic plants and to relate their distributions to remotely-sensed land use types in West Virginia. Collector-defined habitats indicated that the most common habitat was roadsides, but seven of the nine species...

  13. The impact of invasive plants on tidal-marsh vertebrate species: common reed (Phragmites australis) and smooth cordgrass (Spartina alterniflora) as case studies

    Science.gov (United States)

    Guntenspergen, Glenn R.; Nordby, J. Cully

    2006-01-01

    Large areas of tidal marsh in the contiguous US and the Maritime Provinces of Canada are threatened by invasive plant species. Our understanding of the impact these invasions have on tidal-marsh vertebrates is sparse. In this paper, we focus on two successful invasive plant taxa that have spread outside their native range --common reed (Phragmites australis) and smooth cordgrass (Spartina a/terniflora). A cryptic haplotype of common reed has expanded its range in Atlantic Coast tidal marshes and smooth cordgrass, a native dominant plant of Atlantic Coast low-marsh habitat, has expanded its range and invaded intertidal-marsh habitats of the Pacific Coast. The invasions of common reed in Atlantic Coast tidal marshes and smooth cordgrass in Pacific Coast tidal marshes appear to have similar impacts. The structure and composition of these habitats has been altered and invasion and dominance by these two taxa can lead to profound changes in geomorphological processes, altering the vertical relief and potentially affecting invertebrate communities and the entire trophic structure of these systems. Few studies have documented impacts of invasive plant taxa on tidal-marsh vertebrate species in North America. However, habitat specialists that are already considered threatened or endangered are most likely to be affected. Extensive experimental studies are needed to examine the direct impact of invasive plant species on native vertebrate species. Careful monitoring of sites during the initial stages of plant invasion and tracking ecosystem changes through time are essential. Since tidal marshes are the foci for invasion by numerous species, we also need to understand the indirect impacts of invasion of these habitats on the vertebrate community. We also suggest the initiation of studies to determine if vertebrate species can compensate behaviorally for alterations in their habitat caused by invasive plant species, as well as the potential for adaptation via rapid evolution

  14. Comparisons of invasive plants in southern Africa originating from southern temperate, northern temperate and tropical regions

    Directory of Open Access Journals (Sweden)

    L. Henderson

    2006-08-01

    Full Text Available A subset of invasive alien plant species in southern Africa was analysed in terms of their history of introduction, rate of spread, countries/region of origin, taxonomy, growth forms, cultivated uses, weed status and current distribution in southern Africa, and comparisons made of those originating from south of the tropic of Capricorn, north of the tropic of Cancer and from the tropics. The subset of 233 species, belonging to 58 families, includes all important declared species and some potentially important species. Almost as many species originate from temperate regions (112 as from the tropics (121. Most southern temperate species came from Australia (28/36, most tropical species from tropical America (92/121 and most northern temperate species from Europe (including the Mediterranean and Asia (58/76. Transformers account for 33% of  all species. More transformers are of tropical origin (36 than of northern temperate (24 and southern temperate origin (18. However. 50% of southern temperate species are transformers, compared to 32% of northern temperate and 29% of tropical species. Southern temperate transformer species are mainly woody trees and shrubs that were established on a grand scale as silvicultural crops, barriers (hedges, windbreaks and screens and cover/binders. Most aquatics, herbs, climbers and succulent shrubs an. trom the tropics. Ornamentals are the single largest category of plants from all three regions, the tropics having contributed twice as many species as temperate regions.

  15. Propagule Pressure, Habitat Conditions and Clonal Integration Influence the Establishment and Growth of an Invasive Clonal Plant, Alternanthera philoxeroides.

    Science.gov (United States)

    You, Wen-Hua; Han, Cui-Min; Fang, Long-Xiang; Du, Dao-Lin

    2016-01-01

    Many notorious invasive plants are clonal, spreading mainly by vegetative propagules. Propagule pressure (the number of propagules) may affect the establishment, growth, and thus invasion success of these clonal plants, and such effects may also depend on habitat conditions. To understand how propagule pressure, habitat conditions and clonal integration affect the establishment and growth of the invasive clonal plants, an 8-week greenhouse with an invasive clonal plant, Alternanthera philoxeroides was conducted. High (five fragments) or low (one fragment) propagule pressure was established either in bare soil (open habitat) or dense native vegetation of Jussiaea repens (vegetative habitat), with the stolon connections either severed from or connected to the relatively older ramets. High propagule pressure greatly increased the establishment and growth of A. philoxeroides, especially when it grew in vegetative habitats. Surprisingly, high propagule pressure significantly reduced the growth of individual plants of A. philoxeroides in open habitats, whereas it did not affect the individual growth in vegetative habitats. A shift in the intraspecific interaction on A. philoxeroides from competition in open habitats to facilitation in vegetative habitats may be the main reason. Moreover, clonal integration significantly improved the growth of A. philoxeroides only in open habitats, especially with low propagule pressure, whereas it had no effects on the growth and competitive ability of A. philoxeroides in vegetative habitats, suggesting that clonal integration may be of most important for A. philoxeroides to explore new open space and spread. These findings suggest that propagule pressure may be crucial for the invasion success of A. philoxeroides, and such an effect also depends on habitat conditions.

  16. Propagule pressure, habitat conditions and clonal integration influence the establishment and growth of an invasive clonal plant, Alternanthera philoxeroides

    Directory of Open Access Journals (Sweden)

    Wen-Hua eYou

    2016-05-01

    Full Text Available Many notorious invasive plants are clonal, spreading mainly by vegetative propagules. Propagule pressure (the number of propagules may affect the establishment, growth and thus invasion success of these clonal plants, and such effects may also depend on habitat conditions. To understand how propagule pressure, habitat conditions and clonal integration affect the establishment and growth of the invasive clonal plants, an 8-week greenhouse with an invasive clonal plant, Alternanthera philoxeroides was conducted. High (five fragments or low (one fragment propagule pressure was established either in bare soil (open habitat or dense native vegetation of Jussiaea repens (vegetative habitat, with the stolon connections either severed from or connected to the relatively older ramets. High propagule pressure greatly increased the establishment and growth of A. philoxeroides, especially when it grew in vegetative habitats. Surprisingly, high propagule pressure significantly reduced the growth of individual plants of A. philoxeroides in open habitats, whereas it did not affect the individual growth in vegetative habitats. A shift in the intraspecific interaction on A. philoxeroides from competition in open habitats to facilitation in vegetative habitats may be the main reason. Moreover, clonal integration significantly improved the growth of A. philoxeroides only in open habitats, especially with low propagule pressure, whereas it had no effects on the growth and competitive ability of A. philoxeroides in vegetative habitats, suggesting that clonal integration may be of most important for A. philoxeroides to explore new open space and spread. These findings suggest that propagule pressure may be crucial for the invasion success of A. philoxeroides, and such an effect also depends on habitat conditions.

  17. Livestock as a potential biological control agent for an invasive wetland plant

    NARCIS (Netherlands)

    Silliman, Brian R.; Mozdzer, Thomas; Angelini, Christine; Brundage, Jennifer E.; Esselink, Peter; Bakker, Jan P.; Gedan, Keryn B.; van de Koppel, Johan; Baldwin, Andrew H.

    2014-01-01

    Invasive species threaten biodiversity and incur costs exceeding billions of US$. Eradication efforts, however, are nearly always unsuccessful. Throughoutmuch of North America, land managers have used expensive, and ultimately ineffective, techniques to combat invasive Phragmites australis in

  18. Transcriptome Analysis of Invasive Plants in Response to Mineral Toxicity of Reclaimed Coal-Mine Soil in the Appalachian Region.

    Science.gov (United States)

    Saminathan, Thangasamy; Malkaram, Sridhar A; Patel, Dharmesh; Taylor, Kaitlyn; Hass, Amir; Nimmakayala, Padma; Huber, David H; Reddy, Umesh K

    2015-09-01

    Efficient postmining reclamation requires successful revegetation. By using RNA sequencing, we evaluated the growth response of two invasive plants, goutweed (Aegopodium podagraria L.) and mugwort (Artemisia vulgaris), grown in two Appalachian acid-mine soils (MS-I and -II, pH ∼ 4.6). Although deficient in macronutrients, both soils contained high levels of plant-available Al, Fe and Mn. Both plant types showed toxicity tolerance, but metal accumulation differed by plant and site. With MS-I, Al accumulation was greater for mugwort than goutweed (385 ± 47 vs 2151 ± 251 μg g-1). Al concentration was similar between mine sites, but its accumulation in mugwort was greater with MS-I than MS-II, with no difference in accumulation by site for goutweed. An in situ approach revealed deregulation of multiple factors such as transporters, transcription factors, and metal chelators for metal uptake or exclusion. The two plant systems showed common gene expression patterns for different pathways. Both plant systems appeared to have few common heavy-metal pathway regulators addressing mineral toxicity/deficiency in both mine sites, which implies adaptability of invasive plants for efficient growth at mine sites with toxic waste. Functional genomics can be used to screen for plant adaptability, especially for reclamation and phytoremediation of contaminated soils and waters.

  19. Citizen science contributes to our knowledge of invasive plant species distributions

    Science.gov (United States)

    Crall, Alycia W.; Jarnevich, Catherine S.; Young, Nicholas E.; Panke, Brendon; Renz, Mark; Stohlgren, Thomas

    2015-01-01

    Citizen science is commonly cited as an effective approach to expand the scale of invasive species data collection and monitoring. However, researchers often hesitate to use these data due to concerns over data quality. In light of recent research on the quality of data collected by volunteers, we aimed to demonstrate the extent to which citizen science data can increase sampling coverage, fill gaps in species distributions, and improve habitat suitability models compared to professionally generated data sets used in isolation. We combined data sets from professionals and volunteers for five invasive plant species (Alliaria petiolata, Berberis thunbergii, Cirsium palustre, Pastinaca sativa, Polygonum cuspidatum) in portions of Wisconsin. Volunteers sampled counties not sampled by professionals for three of the five species. Volunteers also added presence locations within counties not included in professional data sets, especially in southern portions of the state where professional monitoring activities had been minimal. Volunteers made a significant contribution to the known distribution, environmental gradients sampled, and the habitat suitability of P. cuspidatum. Models generated with professional data sets for the other four species performed reasonably well according to AUC values (>0.76). The addition of volunteer data did not greatly change model performance (AUC > 0.79) but did change the suitability surface generated by the models, making them more realistic. Our findings underscore the need to merge data from multiple sources to improve knowledge of current species distributions, and to predict their movement under present and future environmental conditions. The efficiency and success of these approaches require that monitoring efforts involve multiple stakeholders in continuous collaboration via established monitoring networks.

  20. How do land management practices affect net ecosystem CO2 exchange of an invasive plant infestation?

    Science.gov (United States)

    Sonnentag, O.; Detto, M.; Runkle, B.; Kelly, M.; Baldocchi, D. D.

    2009-12-01

    Ecosystem gas and energy exchanges of invasive plant infestations under different land management practices have been subject of few studies and thus little is known. Our goal is to characterize seasonal changes in net ecosystem CO2 exchange (NEE) through the processes of photosynthesis (GEP) and ecosystem respiration (Reco) of a grassland used as pasture yet infested by perennial pepperweed (Lepidium latifolium) in California’s Sacramento-San Joaquin River Delta. We analyze eddy-covariance supported by environmental and canopy-scale hyperspectral reflectance measurements acquired in 2007-2009. Our study covers three summer drought periods with slightly different land management practices. Over the study period the site was subject to year-round grazing, and in 2008 the site was additionally mowed. Specific questions we address are a) how does pepperweed flowering affect GEP, b) does a mowing event affect NEE mainly through GEP or Reco, and c) can the combined effects of phenology and mowing on pepperweed NEE potentially be tracked using routinely applied remote sensing techniques? Preliminary results indicate that pepperweed flowering drastically decreases photosynthetic CO2 uptake due to shading by the dense arrangement of white flowers at the canopy top, causing the infestation to be almost CO2 neutral. In contrast, mowing causes the infestation to act as moderate net CO2 sink, mainly due to increased CO2 uptake during regrowth. We demonstrate that spectral regions other than commonly-used red and near-infrared might be more promising for pepperweed monitoring because of its spectral uniqueness during the flowering phase. Our results have important implications for land-use land-cover (LULC) change studies when biological invasions and their management alter ecosystem structure and functioning but not necessarily the respective LULC class.

  1. Invasive forb benefits from water savings by native plants and carbon fertilization under elevated CO2 and warming.

    Science.gov (United States)

    Blumenthal, Dana M; Resco, Víctor; Morgan, Jack A; Williams, David G; Lecain, Daniel R; Hardy, Erik M; Pendall, Elise; Bladyka, Emma

    2013-12-01

    As global changes reorganize plant communities, invasive plants may benefit. We hypothesized that elevated CO2 and warming would strongly influence invasive species success in a semi-arid grassland, as a result of both direct and water-mediated indirect effects. To test this hypothesis, we transplanted the invasive forb Linaria dalmatica into mixed-grass prairie treated with free-air CO2 enrichment and infrared warming, and followed survival, growth, and reproduction over 4 yr. We also measured leaf gas exchange and carbon isotopic composition in L. dalmatica and the dominant native C3 grass Pascopyrum smithii. CO2 enrichment increased L. dalmatica biomass 13-fold, seed production 32-fold, and clonal expansion seven-fold, while warming had little effect on L. dalmatica biomass or reproduction. Elevated CO2 decreased stomatal conductance in P. smithii, contributing to higher soil water, but not in L. dalmatica. Elevated CO2 also strongly increased L. dalmatica photosynthesis (87% versus 23% in P. smithii), as a result of both enhanced carbon supply and increased soil water. More broadly, rapid growth and less conservative water use may allow invasive species to take advantage of both carbon fertilization and water savings under elevated CO2 . Water-limited ecosystems may therefore be particularly vulnerable to invasion as CO2 increases. No claim to original US goverment works. New Phytologist © 2013 New Phytologist Trust.

  2. Coexistence via coevolution driven by reduced allelochemical effects and increased tolerance to competition between invasive and native plants.

    Science.gov (United States)

    Huang, Fangfang; Lankau, Richard; Peng, Shaolin

    2018-04-01

    Coevolution can promote long-term coexistence of two competing species if selection acts to reduce the fitness inequality between competitors and/or strengthen negative frequency dependence within each population. However, clear coevolution between plant competitors has been rarely documented. Plant invasions offer opportunities to capture the process of coevolution. Here we investigated how the developing relationship between an invasive forb, Alliaria petiolata, and a native competitor, Pilea pumila, may affect their long-term coexistence, by testing the competitive effects of populations of varying lengths of co-occurrence on each other across a chronosequence of invasion history. Alliaria petiolata and P. pumila tended to develop greater tolerance to competition over invasion history. Their coexistence was promoted more by increases in stabilizing relative to equalizing processes. These changes likely stem in part from reductions in allelopathic traits in the invader and evolution of tolerance in the native. These results suggested that some native species can evolve tolerance against the competitive effects of strong invaders, which likely promoted their persistence in invaded communities. However, the potential for coevolutionary rescue of competing populations is likely to vary across native species, and evolutionary processes should not be expected to compensate for the ecological consequences of exotic invasions. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  3. Invasive non-native plants have a greater effect on neighbouring natives than other non-natives.

    Science.gov (United States)

    Kuebbing, Sara E; Nuñez, Martin A

    2016-09-12

    Human activity is creating a global footprint by changing the climate, altering habitats and reshuffling the distribution of species. The movement of species around the globe has led to the naturalization and accumulation of multiple non-native species within ecosystems, which is frequently associated with habitat disturbance and changing environmental conditions. However, interactions among species will also influence community composition, but little is known about the full range of direct and indirect interactions among native and non-native species. Here, we show through a meta-analysis of 1,215 pairwise plant interactions between 274 vascular plant species in 21 major habitat types that interactions between non-native plants are asymmetrical with interactions between non-native and native plants. Non-native plants were always bad neighbours, but the negative effect of non-natives on natives was around two times greater than the effect of non-natives on other non-natives. In contrast, the performance of non-native plants was five times higher in the presence of a neighbouring native plant species than in the presence of a neighbouring non-native plant species. Together, these results demonstrate that invaded plant communities may accumulate additional non-native species even if direct interactions between non-natives species are negative. Put another way, invasions may be more likely to lead to more invasions, requiring more active management of ecosystems by promoting native species restoration to undermine invasive positive feedback and to assist native species recovery in invaded ecosystems.

  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. Biochar as a biosecurity tool for the management of invasive and/or infected plants.

    Science.gov (United States)

    Harries, Philip J. E.; Fielding, J. James; Alayne Street-Perrott, F.; Doerr, Stefan H.; Brackenbury, Sion

    2014-05-01

    Control of invasive alien/native plants and diseased trees is often achieved using labour-intensive mechanical methods, incurring high costs and significant carbon debt. Disposal of cleared biomass may be heavily regulated. The commonly used method, burning, wastes a potentially valuable resource. Biochar may offer a safe, cost-effective solution to the problem of disposal. Large areas of Wales are covered by bracken (Pteridium aquilinum) (37x103 ha) or invasive Rhododendron ponticum (area not yet quantified). Clearance of these plants is often necessary for agriculture or maintenance of biodiversity (bracken), or to curb the rapid dispersal of the fungus-like pathogen Phytophthora ramorum from rhododendron (the principal host) into commercial timber stands, notably Japanese larch (Larix kaempferi). In addition, ash dieback (the fungal disease Hymenoscyphus pseudoalbidus aka Chalara fraxinea) is now spreading aggressively in common ash trees (Fraxinus excelsior) in the UK. Pilot-scale experiments are being conducted using a BiGchar 1000 mobile, fast pyrolysis -gasification unit, focussing on chipped rhododendron, Japanese larch and common ash feedstocks. Preliminary results of these experiments will be presented. The biochars produced are being subjected to a range of physical and chemical analyses. Levels of micro- and macro-nutrients retained from the original feedstocks are being evaluated. Organic and inorganic contaminants are also being compared with those in the respective feedstocks. Biochar produced from R. ponticum comprised C 63.7-85.9%, H 0.4-0.8%, N 0.4-0.8%, S 0.27-1.79% and O 4.1-27.4%, with most of the mineral nutrients being retained from the original feedstock, especially Mn. Larch biochar comprised C 84.1-91.7%, H 1.8-3.1%, N 0.3-0.8%, S 0.42-0.69% and O 4.1-10.7%. Heavy-metal concentrations were below recommended limits (International Biochar Initiative, 2012), although R. ponticum growing on highly acidified soils showed some tendency to bio

  6. Do invasive alien plants really threaten river bank vegetation? A case study based on plant communities typical for Chenopodium ficifolium-An indicator of large river valleys.

    Science.gov (United States)

    Nobis, Agnieszka; Nowak, Arkadiusz; Rola, Kaja

    2018-01-01

    Riparian zones are very rich in species but subjected to strong anthropogenic changes and extremely prone to alien plant invasions, which are considered to be a serious threat to biodiversity. Our aim was to determine the spatial distribution of Chenopodium ficifolium, a species demonstrating strong confinement to large river valleys in Central Europe and an indicator of annual pioneer nitrophilous vegetation developing on river banks, which are considered to be of importance to the European Community. Additionally, the habitat preferences of the species were analysed. Differences in the richness and abundance of species diagnostic for riverside habitats, as well as the contribution of resident and invasive alien species in vegetation plots along three rivers differing in terms of size and anthropogenic impact were also examined. Finally, the effect of invaders on the phytocoenoses typical for C. ficifolium was assessed. The frequency of C. ficifolium clearly decreased with an increasing distance from the river. Among natural habitats, the species mostly preferred the banks of large rivers. The vegetation plots developing on the banks of the three studied rivers differed in total species richness, the number and cover of resident, diagnostic and invasive alien species, as well as in species composition. Our research indicates that abiotic and anthropogenic factors are the most significant drivers of species richness and plant cover of riverbank vegetation, and invasive alien plants affect this type of vegetation to a small extent.

  7. Suppression of reproductive characteristics of the invasive plant Mikania micrantha by sweet potato competition.

    Science.gov (United States)

    Shen, Shicai; Xu, Gaofeng; Clements, David Roy; Jin, Guimei; Liu, Shufang; Yang, Yanxian; Chen, Aidong; Zhang, Fudou; Kato-Noguchi, Hisashi

    2016-06-20

    As a means of biologically controlling Mikania micrantha H.B.K. in Yunnan, China, the influence of sweet potato [Ipomoea batatas (L.) Lam.] on its reproductive characteristics was studied. The trial utilized a de Wit replacement series incorporating six ratios of sweet potato and M. micrantha plants in 25 m(2) plots over 2 years. Budding of M. micrantha occurred at the end of September; flowering and fruiting occurred from October to February. Flowering phenology of M. micrantha was delayed (P sweet potato. Reproductive allocation, reproductive investment and reproductive index of M. micrantha were significantly reduced (P sweet potato densities. Apidae bees, and Calliphoridae or Syrphidae flies were the most abundant visitors to M. micrantha flowers. Overall flower visits decreased (P sweet potato increased. Thus the mechanism by which sweet potato suppressed sexual reproduction in M. micrantha was essentially two-fold: causing a delay in flowering phenology and reducing pollinator visits. The number, biomass, length, set rate, germination rate, and 1000-grain dry weight of M. micrantha seeds were suppressed (P sweet potato competition. With proportional increases in sweet potato, sexual and asexual seedling populations of M. micrantha were significantly reduced (P sweet potato. These results suggest that sweet potato significantly suppresses the reproductive ability of the invasive species M. micrantha, and is a promising alternative to traditional biological control and other methods of control. Planting sweet potato in conjunction with other control methods could provide a comprehensive strategy for managing M. micrantha. The scenario of controlling M. micrantha by utilizing a crop with a similar growth form may provide a useful model for similar management strategies in other systems.

  8. Four-trophic level food webs reveal the cascading impacts of an invasive plant targeted for biocontrol.

    Science.gov (United States)

    López-Núñez, Francisco A; Heleno, Ruben H; Ribeiro, Sérgio; Marchante, Hélia; Marchante, Elizabete

    2017-03-01

    Biological invasions are a major threat to biodiversity and as such understanding their impacts is a research priority. Ecological networks provide a valuable tool to explore such impacts at the community level, and can be particularly insightful for planning and monitoring biocontrol programmes, including the potential for their seldom evaluated indirect non-target effects. Acacia longifolia is among the worst invasive species in Portugal, and has been recently targeted for biocontrol by a highly specific gall-wasp. Here we use an ambitious replicated network approach to: (1) identify the mechanisms by which direct and indirect impacts of A. longifolia can cascade from plants to higher trophic levels, including gallers, their parasitoids and inquilines; (2) reveal the structure of the interaction networks between plants, gallers, parasitoids and inquilines before the biocontrol; and (3) explore the potential for indirect interactions among gallers, including those established with the biocontrol agent, via apparent competition. Over a 15-month period, we collected 31,737 galls from native plants and identified all emerging insects, quantifying the interactions between 219 plant-, 49 galler-, 65 parasitoid- and 87 inquiline-species-one of the largest ecological networks to date. No galls were found on any of the 16 alien plant species. Invasion by A. longifolia caused an alarming simplification of plant communities, with cascading effects to higher trophic levels, namely: a decline of overall gall biomass, and on the richness, abundance and biomass of galler insects, their parasitoids, and inquilines. Correspondingly, we detected a significant decline in the richness of interactions between plants and galls. The invasion tended to increase overall interaction evenness by promoting the local extinction of the native plants that sustained more gall species. However, highly idiosyncratic responses hindered the detection of further consistent changes in network

  9. Arbuscular and Ectomycorrhizal Fungi Associated with the Invasive Brazilian Pepper Tree (Schinus terebinthifolius) and Two Native Plants in South Florida.

    Science.gov (United States)

    Dawkins, Karim; Esiobu, Nwadiuto

    2017-01-01

    The potential role of soil fungi in the invasion of the Brazilian pepper tree ( Schinus terebinthifolius -BP) in Florida is not known; although the low biotic resistance of Florida soils is often invoked to explain the prevalence of many invasive species. To gain an initial insight into BP's mycorrhizal associations, this study examined the rhizobiome of BP and two native plants ( Hamelia patens and Bidens alba ) across six locations. Arbuscular mycorrhizal fungi (AMF) associated with the roots of the target plants and bulk soil was characterized by spore morphotyping. Sequence analysis of metagenomic DNA from lateral roots/rhizosphere of BP ( n = 52) and a native shrub H. patens ( n = 37) on the same parcel yielded other fungal associates. Overall, the total population of AMF associated with BP was about two folds greater than that of the two native plants ( p = 0.0001) growing on the same site. The dominant AMF under Schinus were members of the common Glomus and Rhizophagus spp. By contrast, the most prevalent AMF in the bulk soil and rhizosphere of the two Florida native plants, Acaulospora spp (29%) was sharply diminished (9%) under BP rhizosphere. Analysis of the ITS2 sequences also showed that Schinus rhizosphere had a high relative abundance of ectomycorrhizal fungi (76.5%) compared to the native H. patens (2.6%), with the species Lactifluus hygrophoroides (Basidiomycota) being the most prevalent at 61.5% ( p < 0.05). Unlike the native plants where pathogenic fungi like Phyllosticta sp., Phoma sp., and Neofusicoccum andium were present (8.1% for H. patens ), only one potentially pathogenic fungal taxon was detected (3.9%) under BP. The striking disparity in the relative abundance of AMF and other fungal types between BP and the native species is quite significant. Fungal symbionts could aide plant invasion via resource-use efficiency and other poorly defined mechanisms of protection from pathogens in their invaded range. This report exposes a potentially

  10. Genotypic diversity of an invasive plant species promotes litter decomposition and associated processes.

    Science.gov (United States)

    Wang, Xiao-Yan; Miao, Yuan; Yu, Shuo; Chen, Xiao-Yong; Schmid, Bernhard

    2014-03-01

    Following studies that showed negative effects of species loss on ecosystem functioning, newer studies have started to investigate if similar consequences could result from reductions of genetic diversity within species. We tested the influence of genotypic richness and dissimilarity (plots containing one, three, six or 12 genotypes) in stands of the invasive plant Solidago canadensis in China on the decomposition of its leaf litter and associated soil animals over five monthly time intervals. We found that the logarithm of genotypic richness was positively linearly related to mass loss of C, N and P from the litter and to richness and abundance of soil animals on the litter samples. The mixing proportion of litter from two sites, but not genotypic dissimilarity of mixtures, had additional effects on measured variables. The litter diversity effects on soil animals were particularly strong under the most stressful conditions of hot weather in July: at this time richness and abundance of soil animals were higher in 12-genotype litter mixtures than even in the highest corresponding one-genotype litter. The litter diversity effects on decomposition were in part mediated by soil animals: the abundance of Acarina, when used as covariate in the analysis, fully explained the litter diversity effects on mass loss of N and P. Overall, our study shows that high genotypic richness of S. canadensis leaf litter positively affects richness and abundance of soil animals, which in turn accelerate litter decomposition and P release from litter.

  11. Determining the feasibility of harvesting invasive alien plant species for energy

    Directory of Open Access Journals (Sweden)

    Worship Mugido

    2014-11-01

    Full Text Available Woody invasive alien plants (IAPs are a threat to South Africa's water resources, biodiversity and land productivity. The impacts of IAPs were the main reason for the South African government to embark on a natural resource management public works programme called Working for Water (WfW, which was aimed at controlling IAPs in a cost-effective yet labour-intensive way. At the same time, the high biomass of these species presents opportunities for synergies between the clearing of IAPs and the generation of biomass-based energy. The purpose of this study was to determine the cost of harvesting and extracting, chipping, and transporting the biomass, and also to determine the financial and economic feasibility of such an exercise from a commercial perspective. Sampling of the biomass was done at 31 representative sites within the Nelson Mandela Metropolitan Municipality, South Africa. The cost of the operation was carefully monitored, documented and reported at each stage, and compared to the cost of replacing the thermal coal currently used by industry within this municipality. The project proved to be financially viable, but only when the energy entrepreneur forms a partnership with the WfW programme, and then only under specific conditions. The project has, however, very high socio-economic returns with respect to a reduction in environmental externalities and job creation.

  12. A new strategy for controlling invasive weeds: selecting valuable native plants to defeat them.

    Science.gov (United States)

    Li, Weihua; Luo, Jianning; Tian, Xingshan; Soon Chow, Wah; Sun, Zhongyu; Zhang, Taijie; Peng, Shaolin; Peng, Changlian

    2015-06-05

    To explore replacement control of the invasive weed Ipomoea cairica, we studied the competitive effects of two valuable natives, Pueraria lobata and Paederia scandens, on growth and photosynthetic characteristics of I. cairica, in pot and field experiments. When I. cairica was planted in pots with P. lobata or P. scandens, its total biomass decreased by 68.7% and 45.8%, and its stem length by 33.3% and 34.1%, respectively. The two natives depressed growth of the weed by their strong effects on its photosynthetic characteristics, including suppression of leaf biomass and the abundance of the CO2-fixing enzyme RUBISCO. The field experiment demonstrated that sowing seeds of P. lobata or P. scandens in plots where the weed had been largely cleared produced 11.8-fold or 2.5-fold as much leaf biomass of the two natives, respectively, as the weed. Replacement control by valuable native species is potentially a feasible and sustainable means of suppressing I. cairica.

  13. A new strategy for controlling invasive weeds: selecting valuable native plants to defeat them

    Science.gov (United States)

    Li, Weihua; Luo, Jianning; Tian, Xingshan; Soon Chow, Wah; Sun, Zhongyu; Zhang, Taijie; Peng, Shaolin; Peng, Changlian

    2015-06-01

    To explore replacement control of the invasive weed Ipomoea cairica, we studied the competitive effects of two valuable natives, Pueraria lobata and Paederia scandens, on growth and photosynthetic characteristics of I. cairica, in pot and field experiments. When I. cairica was planted in pots with P. lobata or P. scandens, its total biomass decreased by 68.7% and 45.8%, and its stem length by 33.3% and 34.1%, respectively. The two natives depressed growth of the weed by their strong effects on its photosynthetic characteristics, including suppression of leaf biomass and the abundance of the CO2-fixing enzyme RUBISCO. The field experiment demonstrated that sowing seeds of P. lobata or P. scandens in plots where the weed had been largely cleared produced 11.8-fold or 2.5-fold as much leaf biomass of the two natives, respectively, as the weed. Replacement control by valuable native species is potentially a feasible and sustainable means of suppressing I. cairica.

  14. 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.

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

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    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.

  16. Does crotalaria (Crotalaria breviflora or pumpkin (Cucurbita moschata inter-row cultivation in restoration plantings control invasive grasses?

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    Ricardo Gomes César

    2013-08-01

    Full Text Available Alternative methods to control invasive fodder grasses are necessary to reduce the use of herbicides in forest restoration, which has been carried out primarily in riparian zones. We sought to investigate if inter-row cultivation of crotalaria (Crotalaria breviflora DC or pumpkin (Cucurbita moschata Duschene ex. Poir with native tree species is an efficient strategy to control invasive fodder grasses in restoration plantings. We tested five treatments in a randomized block design, namely (1 control of brachiaria grass (Urochloa decumbens (Stapf. Webster with glyphosate in the implementation and post-planting grass control of the reforestation, (2 and 3 glyphosate use in the implementation and inter-row sowing of crotalaria (2 or pumpkin (3, and control of brachiaria by mowing in the post-planting phase, (4 and 5 mowing in the implementation and inter-row sowing of crotalaria (4 or pumpkin (5, and control of brachiaria by mowing in the post-planting phase. Post-planting grass control was carried out four and nine months after tree seedling planting. Throughout 13 months, we evaluated the percentage of ground cover by brachiaria grass, pumpkin production, and native tree seedling mortality, height and crown cover. The exclusive use of glyphosate, without inter-row sowing of pumpkin or crotalaria showed the most favorable results for controlling brachiaria grass and, consequently, for tree seedling development. Hence, inter-row cultivation of green manure or short-lived crop species is not enough to control invasive grasses in restoration plantings, and complementary weeding is necessary to reduce the highly competitive potential of C4 grasses for supporting native species seedlings growth.

  17. Biodiversity of Soil Microbial Communities Following Woody Plant Invasion of Grassland: An Assessment Using Molecular Methods

    Science.gov (United States)

    Kantola, I. B.; Gentry, T. J.; Filley, T. R.; Boutton, T. W.

    2012-12-01

    Woody plants have encroached into grasslands, savannas, and other grass-dominated ecosystems throughout the world during the last century. This dramatic vegetation change is likely driven by livestock grazing, altered fire frequencies, elevated atmospheric CO2 concentrations, and/or changes in atmospheric deposition patterns. Woody invasion often results in significant changes in ecosystem function, including alterations in above- and belowground primary productivity, soil C, N, and P storage and turnover, and the size and activity of the soil microbial biomass pool. The purpose of this study was to examine the relationships and interactions between plant communities and soil microbial communities in the Rio Grande Plains region of southern Texas where grasslands have been largely replaced by woodlands. Research was conducted along a successional chronosequence representing the stages of woody plant encroachment from open grassland to closed-canopy woodland. To characterize soil microbial community composition, soil samples (0-7.5 cm) were collected in remnant grasslands (representing time 0) and near the centers of woody plant clusters, groves, and drainage woodlands ranging in age from 10 to 130 yrs. Ages of woody plant stands were determined by dendrochronology. Community DNA was extracted from each soil sample with a MoBio PowerMax Soil DNA isolation kit. The DNA concentrations were quantified on a NanoDrop ND-1000 spectrophotometer and diluted to a standard concentration. Pyrosequencing was performed by the Research and Testing Laboratory (Lubbock, TX) according to Roche 454 Titanium chemistry protocols. Samples were amplified with primers 27F and 519R for bacteria, and primers ITS1F and ITS4 for fungi. Sequences were aligned using BioEdit and the RDP Pipeline and analyzed in MOTHUR. Non-metric multidimensional scaling of the operational taxonomic units identified by pyrosequencing revealed that both bacterial and fungal community composition were

  18. Hieracium sylvularum (Asteraceae in the Mordovia State Nature Reserve: invasive plant or historical heritage of the flora?

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    Anatoliy A. Khapugin

    2017-11-01

    Full Text Available Protected Areas are considered as one of the most appropriate tool for biodiversity conservation. However, invasion of alien species is one of the main and widely known problems of these territories. Therefore, the timely detection and prevention of the invasive species dispersal is one of the main tasks of researchers in Protected Areas. The European species Hieracium sylvularum was found in the Mordovia State Nature Reserve in 2012. In the following years, new locations have been discovered there. That is why the main traits of the ecology and biology, invasiveness level of the alien species were studied. An investigation of the five known H. sylvularum locations has been carried out in the Mordovia Reserve. Attention has been paid to the age-structure of the populations, the accompanying floras' composition and morphometrical parameters of the generative individuals. The environmental conditions of habitats were revealed and compared using phytoindication methods. The mass and germination of seeds, harvested on different locations, were studied. The results indicate that H. sylvularum is not an invasive species. This alien plant is able to reproduce primarily vegetatively. Probably, the population area can extend gradually on each location. Seed dispersal is difficult due to low germinability of seeds, despite of their significant number per plant. Based on obtained results, dry and semi-dry light lichen-moss-Pinus-forests have a higher invasibility by H. sylvularum. Therefore, perhaps, its new locations may be found especially in these habitats. Annual monitoring of the currently known locations of this alien plant is necessary in the Mordovia State Nature Reserve.

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

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    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.

  20. Plant community resistance to invasion by Bromus species – the roles of community attributes, Bromus Interactions with plant communities, and Bromus traits

    Science.gov (United States)

    Chambers, Jeanne; Germino, Matthew; Belnap, Jayne; Brown, Cynthia; Schupp, Eugene W.; St. Clair, Samuel B

    2016-01-01

    The factors that determine plant community resistance to exotic annual Bromus species (Bromushereafter) are diverse and context specific. They are influenced by the environmental characteristics and attributes of the community, the traits of Bromus species, and the direct and indirect interactions of Bromus with the plant community. Environmental factors, in particular ambient and soil temperatures, have significant effects on the ability of Bromus to establish and spread. Seasonality of precipitation relative to temperature influences plant community resistance toBromus through effects on soil water storage, timing of water and nutrient availability, and dominant plant life forms. Differences among plant communities in how well soil resource use by the plant community matches resource supply rates can influence the magnitude of resource fluctuations due to either climate or disturbance and thus the opportunities for invasion. The spatial and temporal patterns of resource availability and acquisition of growth resources by Bromus versus native species strongly influence resistance to invasion. Traits of Bromus that confer a “priority advantage” for resource use in many communities include early-season germination and high growth and reproductive rates. Resistance to Bromus can be overwhelmed by high propagule supply, low innate seed dormancy, and large, if short-lived, seed banks. Biological crusts can inhibit germination and establishment of invasive annual plants, including several annual Bromus species, but are effective only in the absence of disturbance. Herbivores can have negative direct effects on Bromus, but positive indirect effects through decreases in competitors. Management strategies can be improved through increased understanding of community resistance to exotic annual Bromus species.