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- Carduus acanthoides; Carduus nutans; central Pennsylvania USA; co-invasion; competition; congeners; invasional interference; invader–invader interactions; invasion ecology; invasive species management; thistles (1)
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Articles 1 - 10 of 10
Full-Text Articles in Weed Science
Salvinia Molesta: An Assessment Of The Effects And Methods Of Eradication, Arti Lal
Salvinia Molesta: An Assessment Of The Effects And Methods Of Eradication, Arti Lal
Master's Projects and Capstones
Salvinia molesta is an invasive aquatic fern. It is now the second worse aquatic invader in the world. Since the 1930s, it has invaded most tropical and some temperate countries. S. molesta plants grow vegetatively and can increase in size rapidly. S. molesta can form thick mats of up to 1-meter-thick. There are a number of ways these thick mats negatively affect the environment: 1) reduce light to benthic organisms, 2) reduce oxygen in the water column for other organisms, 3) accumulate as organic matter at the bottom of the water column, 4) decrease nutrients for other organisms, and 5) …
Slow Spread Of The Aggressive Invader, Microstegium Vimineum (Japanese Stiltgrass), Emily S.J. Rauschert, David A. Mortensen, Ottar N. Bjørnstad, Andrea N. Nord, Nora Peskin
Slow Spread Of The Aggressive Invader, Microstegium Vimineum (Japanese Stiltgrass), Emily S.J. Rauschert, David A. Mortensen, Ottar N. Bjørnstad, Andrea N. Nord, Nora Peskin
Emily Rauschert
Microstegium vimineum (Japanese stiltgrass) is a non-native weed whose rapid invasion threatens native diversity and regeneration in forests. Using data from a 4 year experiment tracking new invasions in different habitats, we developed a spatial model of patch growth, using maximum likelihood techniques to estimate dispersal and population growth parameters. The patches expanded surprisingly slowly: in the final year, the majority of new seedlings were still within 1 m of the original patch. The influence of habitat was not as strong as anticipated, although patches created in roadside and wet meadow habitats tended to expand more rapidly and had greater …
Plant Community Associations Of Two Invasive Thistles, Emily S.J. Rauschert, Katriona Shea, Sarah Goslee
Plant Community Associations Of Two Invasive Thistles, Emily S.J. Rauschert, Katriona Shea, Sarah Goslee
Emily Rauschert
In order to combat the growing problems associated with biological invasions, many researchers have focused on identifying which communities are most vulnerable to invasion by exotic species. However, once established, invasive species can significantly change the composition of the communities that they invade. The first step to disentangling the direction of causality is to discern whether a relationship with other vegetation exists at all. Carduus nutans and C. acanthoides are similar invasive thistles, which have caused substantial economic damage worldwide. We assessed the associations between the thistles and the standing flora in four sites in central Pennsylvania in which they …
Japanese Stiltgrass: An Invasive Plant On The Move, Emily S.J. Rauschert, Andrea N. Nord
Japanese Stiltgrass: An Invasive Plant On The Move, Emily S.J. Rauschert, Andrea N. Nord
Emily Rauschert
No abstract provided.
Coexistence Patterns Of Two Invasive Thistle Species, Carduus Nutans And C. Acanthoides, At Three Spatial Scales, Emily S.J. Rauschert, Katriona Shea, Ottar N. Bjørnstad
Coexistence Patterns Of Two Invasive Thistle Species, Carduus Nutans And C. Acanthoides, At Three Spatial Scales, Emily S.J. Rauschert, Katriona Shea, Ottar N. Bjørnstad
Emily Rauschert
To better understand the competitive processes involved in invasion by congeners, we examine coexistence patterns of two invasive species, Carduus nutans and C. acanthoides, at three spatial scales. A roadside survey of 5 × 5 km blocks in a previously identified overlap zone provided information about the regional scale. At smaller scales, we surveyed four fields of natural co-occurrence, quantifying the spatial patterns at the field scale by randomly placed 1 × 1 m quadrats and at the smallest scale by detailing plant position within the quadrats. The patterns observed are strikingly different at the different scales. At the regional …
Influence Of Microsite Disturbance On The Establishment Of Two Congeneric Invasive Thistles, Emily S.J. Rauschert, Katriona Shea
Influence Of Microsite Disturbance On The Establishment Of Two Congeneric Invasive Thistles, Emily S.J. Rauschert, Katriona Shea
Emily Rauschert
The successful establishment of invasive species has been shown to depend on aspects of the invaded community, such as gap characteristics. Biotic resistance may be particularly critical for stopping invaders at early life history stages, but new species can often invade following disturbances, which may create microsites with very different characteristics than are usually present. We examine the response of two invasive thistle species, Carduus nutans L. and C. acanthoides L., to three different microsite characteristics: disturbance type, size, and water availability. The two species initially responded differently to the type of disturbance: C. acanthoides had higher emergence and survival …
Invasional Interference Due To Similar Inter- And Intraspecific Competition Between Invaders May Affect Management, Emily S.J. Rauschert, Katriona Shea
Invasional Interference Due To Similar Inter- And Intraspecific Competition Between Invaders May Affect Management, Emily S.J. Rauschert, Katriona Shea
Emily Rauschert
As the number of biological invasions increases, the potential for invader– invader interactions also rises. The effect of multiple invaders can be superadditive (invasional meltdown), additive, or subadditive (invasional interference); which of these situations occurs has critical implications for prioritization of management efforts. Carduus nutans and C. acanthoides, two congeneric invasive weeds, have a striking, segregated distribution in central Pennsylvania, USA. Possible hypotheses for this pattern include invasion history and chance, direct competition, or negative interactions mediated by other species, such as shared pollinators. To explore the role of resource competition in generating this pattern, we conducted three related experiments …
Chemically Mediated Interactions Between Hosts, Parasitic Plants And Insect Herbivores, Muvari C. Tjiurutue
Chemically Mediated Interactions Between Hosts, Parasitic Plants And Insect Herbivores, Muvari C. Tjiurutue
Doctoral Dissertations
Species interactions, by changing phenotypic traits, can alter the outcome of subsequent interactions. Plant-mediated responses to herbivores have been extensively studied, but little is known about plant-mediated responses involving parasitic plants within a broader community context that also includes herbivores. Because parasitic plants are important components of many ecosystems and can shape community structure, it is important to understand how host-mediated interactions influence parasite preference and success. The goal of this thesis is to examine interactions between hosts, parasitic plants and herbivores mediated by chemical traits. We first examined the effects of dodder (Cuscuta sp.) parasitism on induced defenses …
Evaluating The Myth Of Allelopathy In California Blue Gum Plantations, Kristen Marie Nelson
Evaluating The Myth Of Allelopathy In California Blue Gum Plantations, Kristen Marie Nelson
Master's Theses
It is widely accepted that allelopathy is not only significant, but more or less singular, in the inhibition of understory vegetation in California Eucalyptus globulus (blue gum) plantations. However, there is no published documentation of allelopathy by blue gums against California native species. Here, we present evidence that germination and early seedling growth of five California native species are not inhibited by chemical extracts of blue gum foliage, either at naturally-occurring or artificially concentrated levels. In the greenhouse, seeds were germinated in field-collected soil from mature blue gum plantations and the adjacent native, coastal scrub communities. In petri plates, seeds …
Plant Functional Trait And Hyperspectral Reflectance Responses To Comp B Exposure: Efficacy Of Plants As Landmine Detectors, Paul V. Manley Ii
Plant Functional Trait And Hyperspectral Reflectance Responses To Comp B Exposure: Efficacy Of Plants As Landmine Detectors, Paul V. Manley Ii
Theses and Dissertations
At least 110 million landmines have been planted since the 1970s in about 70 nations, many of which remain in place today. Some risk of detection may be mitigated using currently available remote sensing techniques when vegetation is present. My study focused on using plants as phytosensors to detect buried explosives. I exposed three species representing different functional types (Cyperus esculentus (sedge), Ulmus alata (tree), Vitis labrusca (vine)) to 500 mg kg-1 of Composition B (Comp B; 60/40 mixture of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene (TNT)), a commonly used explosive mixture, and measured functional traits and reflectance over …