Invasive plants are a significant threat to native ecosystems and to biodiversity. They are often strong competitors and have multiple techniques to outcompete native plants. Thus, controlling or removing invasive plants facilitates the restoration of native ecosystems. We used GPS technology coupled with field surveying techniques adapted from the U.S. Fish and Wildlife Service to locate and identify invasive plants present within VCU’s Rice Rivers Center. We digitally overlaid a 50-meter x 50-meter grid system over the property. In each grid cell we recorded visual estimations of invasive plant coverage sorted into modified Daubenmire cover classes and used ArcGIS for mapping and analysis. Altogether, we found 25 unique invasive plant species. 93% of the grid cells contained at least one invasive species, and one grid cell contained seven unique species. The influence of anthropogenic disturbance on invasive species distribution, analyzed by using a 50-meter wide buffer zone around each disturbance (e.g., roads, buildings, etc.), showed that the presence and coverage of invasive species was greater within disturbed areas compared to intact forest. Microstegium vimineum, Lonicera japonica, and Ligustrum sinense were most common and widely distributed within terrestrial habitats, while Murdannia keisak was most widely distributed in the restored wetland. Our results for M. vimineum were compared to a similar 2004 study: this species has since spread from 40% to 76% of the grid cells. The spatial maps we have created will be a foundation for an integrated invasive species management program at the Rice Rivers Center and will assist with management, control and restoration efforts within terrestrial and aquatic ecosystems.

Invasive alien plants have impacted southern U.S. forests. This study focuses on quantifying current distribution, rate of dispersals, and economic losses caused by four major invaders — Chinese tallow (Triadica sebifera (L.) Small), Chinese Privet (Ligustrum sinense Lour.), European Privet (Ligustrum vulgare L.), and Japanese Honeysuckle (Lonicera japonica Thunb.). Using data from USDA Forest Service’s Forest Inventory and Analysis (FIA), National Oceanic and Atmospheric Administration (NOAA), and USGS Land Use and Land Cover (LULC), I first used logistic regressions to build occupation models for these four species. Second, I used VB.NET© (Microsoft, 2003) and Environment System Research Institute (ESRI) Arc View® 9.2 Geographical Information System (GIS) to model spatially explicit dispersal dynamics of these species. Finally, I evaluated economic losses associated with these invasions. The results of occupation models showed that landscape features, climatic conditions, forest and site conditions, forest management activities and disturbances, and forest ownership have statistically significant impacts on current distributions of all four species. The results of dispersal models showed that invasions of Chinese tallow, Chinese and European privets, and Japanese honeysuckle will be likely to appear on approximately 6.65 million acres of forest land in East Texas and Louisiana, 3.81 million acres in Mississippi and Alabama, and 12.55 million acres in Mississippi and Alabama, respectively, during the next 20 years. The estimated timber losses resulting from the invasion with no control for the next 20 years at 5% discount rate is 518 million dollars for Chinese tallow, 2.72 billion dollars for Chinese and European privets, and 11.05 billion dollars for Japanese honeysuckle. From an economic point of view, it would be most cost effective to execute high intensity control for these invasive species. Based on these findings, strategies for monitoring and mitigating these invasive species are proposed.

Soil fungi play an important role in regulating plant communities as well as above and below ground ecosystem-level processes; conversely, plant communities may also affect the structure and functionality of these root-associating fungi. Alteration of these fungal communities due to non-native plant invasion has the potential to disrupt biogeochemical cycling, soil structure, and plant growth. Both beneficial symbionts such as arbuscular mycorrhizal fungi (AMF) as well as the total fungal community are potentially altered by aggressive invasive plant species in such a way as to disrupt existing native endophytic fungal communities in the soil post invasion. This disruption could provide a pathway for invasion and suggests the importance of investigating plant-fungal associations in invaded ranges. I used molecular techniques to characterize the fungal communities colonizing Vincetoxicum rossicum or Dog-strangling vine (DSV) and Alliaria petiolata or garlic mustard, both European natives that are currently well established in Eastern North America, as well as native plants that are commonly found persisting in the presence of dense colonies of DSV, as well as those same natives growing separately from DSV. Fungi colonizing different plant groups were analyzed using primers that target the internal transcribed spacer region of the ribosomal operon in order to amplify total fungal species (TF), as well as primers designed to exclusively amplify AMF using small subunit rRNA sequences. Significant differences were observed in the diversity of both the TF and the AMF communities colonizing native plants in the invaded sites relative to the uninvaded sites. Sequencing work indicated that DSV forms associations with a broad array of fungal partners relative to proximal native plants, suggesting the likelihood of it being a fungal generalist. As well, DSV was found to associate with described opportunistic AMF such as Glomus intraradices, G. caledonium, G. fasciculatum and G. mosseae, while natives growing within DSV patches were not. Finally, garlic mustard was found to have the dominant effect where DSV and garlic mustard were co-occurring. These findings support the ongoing investigations into plant invasion processes, and therefore contribute to the development of effective strategies for invasive species management as well as site restoration techniques.

Soil fungi play an important role in regulating plant communities as well as above and below ground ecosystem-level processes; conversely, plant communities may also affect the structure and functionality of these root-associating fungi. Alteration of these fungal communities due to non-native plant invasion has the potential to disrupt biogeochemical cycling, soil structure, and plant growth. Both beneficial symbionts such as arbuscular mycorrhizal fungi (AMF) as well as the total fungal community are potentially altered by aggressive invasive plant species in such a way as to disrupt existing native endophytic fungal communities in the soil post invasion. This disruption could provide a pathway for invasion and suggests the importance of investigating plant-fungal associations in invaded ranges. I used molecular techniques to characterize the fungal communities colonizing Vincetoxicum rossicum or Dog-strangling vine (DSV) and Alliaria petiolata or garlic mustard, both European natives that are currently well established in Eastern North America, as well as native plants that are commonly found persisting in the presence of dense colonies of DSV, as well as those same natives growing separately from DSV. Fungi colonizing different plant groups were analyzed using primers that target the internal transcribed spacer region of the ribosomal operon in order to amplify total fungal species (TF), as well as primers designed to exclusively amplify AMF using small subunit rRNA sequences. Significant differences were observed in the diversity of both the TF and the AMF communities colonizing native plants in the invaded sites relative to the uninvaded sites. Sequencing work indicated that DSV forms associations with a broad array of fungal partners relative to proximal native plants, suggesting the likelihood of it being a fungal generalist. As well, DSV was found to associate with described opportunistic AMF such as Glomus intraradices, G. caledonium, G. fasciculatum and G. mosseae, while natives growing within DSV patches were not. Finally, garlic mustard was found to have the dominant effect where DSV and garlic mustard were co-occurring. These findings support the ongoing investigations into plant invasion processes, and therefore contribute to the development of effective strategies for invasive species management as well as site restoration techniques.

Magister Scientiae (Biodiversity and Conservation Biology) / The spread of invasive species is one of the greatest threats to global biodiversity. Alien plant invasions also have serious economic impact in terms of the delivery of ecosystem goods and services. Studies of biological invasions in southern Africa have tended to overlook grasses (family Poaceae), although there are many naturalised species in the region. Only a few of these, all perennials, have been officially categorised as invasive in South Africa, but in the winter rainfall region of the Western Cape, grass invasion especially by Mediterranean European annuals have also been noted. These grasses can be difficult to identify. DNA barcoding has been suggested as an alternative method of identifying grasses in the hope of facilitating identification of existing invaders and preventing future invasions. In this study a list of all known naturalised grasses in South Africa was compiled, and a DNA barcoding reference database was assembled for these naturalised grass species as well as for native southern African grass species. The two official markers for plant DNA barcoding (rbcLa + matK) were used in barcoding and phylogenetic analyses, both individually and in combination. The barcoding data was assessed for identification efficacy using three distance-based metrics and one tree-based metric in the R package SPIDER, both including and excluding singleton data. This study lists 128 naturalised grass species and subspecies found in South Africa. In the DNA barcoding analyses, matK was found to perform better as a single barcode than rbcLa, with identification success rates of up to 84% for matK and 76% for rbcLa, using the most successful metric which was the Nearest Neighbour criterion for both of these markers in the data sets without singletons. The combined rbcLa + matK data set performed better than either of the two individual markers, with identification success rates of up to 91% in the data without singletons, with the most successful metric again being the Nearest Neighbour criterion. The combined rbcLa + matK data would therefore be the recommended DNA barcode for southern African grasses of the three data sets tested, based on the results of this study. Phylogenetic trees were constructed with the DNA barcoding data using Bayesian Inference (BI) and Maximum Parsimony (MP) to assess the usefulness of the data in phylogenetic studies and to confirm the efficacy of this grass DNA barcoding data when using tree-based methods of identification. Both the matK and combined datasets resolved all of the grass tribes represented in this study as monophyletic, but the rbcLa data did not.

No description available.

Invasive species are an increasing problem worldwide, threatening indigenous communities and species. In a world where people travel and trade a lot in a global market, many organisms are transported to new parts of the world where they have never existed before. Most do not survive in the new environment but die, but some thrive and thrive. When such species are established and multiply in places outside their natural range, it can be followed by negative consequences for species that have existed there for a long time - so-called indigenous species. Then the new species are often called alien invasive species. An example of this is the beautiful and colourful plant flower lupin (Lupinus polyphyllus)that people on their travels brought with them from North America, among other things, Europe. Global warming and increased trade between countries is the main reason why foreign species are introduced to new ecosystems while climate change means that habitats can change to become more suitable for an invasive alien species. The invasive species currently causes major economic losses worldwide. Lupins, park slides, and giant sheds are examples of invasive plants that have been introduced in European gardens because they are beautiful and easy to care for. They are also invasive, spread aggressively and are detrimental to our nature because they penetrate our native species. To stop these invasive plants and from damaging Europe's nature, the EU countries have decided to take action against certain species. On January 1, 2015, the EU adopted a regulation on invasive alien species and how to combat it within the Union. On February 5, 2016, the Swedish Environmental Protection Agency submitted the Authority's proposal to the Swedish Government on new rules and measures on how to stop invasive harmful species. Already today, great resources are being devoted to combating invading plants such in our nature reserves. However, an early preventive or direct targeted intervention is much more cost effective than a continuous control of unwanted, invasive species with well-established populations. In order to succeed in this, we need an increased awareness of the problem of alien, invasive species among the public and decision makers, but also a sharp global analysis. Only with knowledge and continuous monitoring can we put in early action against future, aggressive invaders.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O processo de introdução de espécies é reconhecido como a segunda causa mais importante de erosão da diversidade biológica em muitos ambientes no Brasil e no mundo. As espécies invasoras possuem não apenas o poder de sobrevivência e adaptação em outros ambientes, mas a capacidade de dominar a diversidade biológica nativa através da alteração das características básicas dos processos ecológicos naturais e das interações. A jaqueira, Artocarpus heterophyllus Lamarck (Moraceae), tem sua origem nas florestas tropicais da Índia, tendo sido introduzida no Brasil ainda no período Colonial e atualmente é invasora em áreas de Mata Atlântica. Este estudo fornece os primeiros dados sobre a influência da espécie exótica invasora Artocarpus heterophyllus sobre comunidades de anuros de folhiço. As amostragens foram realizadas em uma área de Mata Atlântica, no litoral sudoeste do estado do Rio de Janeiro, incluindo informações sobre riqueza de espécies, densidades específicas e parâmetros ambientais. Nosso estudo foi realizado no Parque Estadual da Ilha Grande entre janeiro de 2009 e março de 2011. Para amostrar a comunidade de anuros de folhiço usamos 154 parcelas de 5 x 5 m, sendo 77 delas em áreas com jaqueiras e 77 em áreas sem jaqueiras, totalizando 3.850 m de chão de floresta amostrados. Nós amostramos um total de 613 anuros habitando o chão da floresta, pertencentes a dez espécies: Brachycephalus didactylus; Chiasmocleis sp.; Haddadus binotatus; Ischnocnema guentheri; Ischnocnema octavioi; Ischnocnema parva; Leptodactylus marmoratus; Physalaemus signifer; Rhinnela ornata e Zachaenus parvulus. Seis das dez espécies foram comuns às áreas com e sem jaqueiras, sendo a similaridade entre as duas áreas de 60%. As áreas com jaqueiras tiveram o dobro (N = 18) de parcelas sem nenhum anfíbio. O número de anfíbios registrados nas parcelas com jaqueiras (38%) foi menor do que o encontrado nas áreas sem jaqueiras (62%). O anfíbio predominante no folhiço em ambas às condições foi Ischnocnema parva, tendo abundancia maior nas parcelas sem jaqueiras. A densidade total de anuros vivendo no chão da floresta nas áreas com jaqueiras (12,2 ind/100 m) foi menor que nas áreas sem jaqueiras (19,7 ind/100 m). Entre os parâmetros ambientais analisados os que possuíram maior influência sobre a abundância de anfíbios foram a profundidade do folhiço e o pH do solo. Os dados sugerem que a jaqueira, além de ocupar o habitat de espécies nativas, é capaz de promover alterações na estrutura desses habitats que irão intervir na fauna do local. / The process of species introduction is recognized as the second most important cause of biological diversity erosion in many environments in Brazil and worldwide. Invasive species have not only the power to survive and adapt in other environments, but also the ability to master the native biodiversity by altering the basic characteristics of natural ecological processes and interactions. The jackfruit tree, Artocarpus heterophyllus Lamarck (Moraceae), has its origin in the tropical forests of India, being introduced in Brazil during the Colonial period and is currently invading the Atlantic Forest. In this study we provide the first data about the influence of the invasive alien species Artocarpus heterophyllus on anuran communities. Samples were taken in an area of Atlantic Forest, on the Southwest coast of the State of Rio de Janeiro, and included information on species richness, density and environmental parameters. Our study was conducted at the Ilha Grande State Park, between January 2009 and March 2011. To sample the community of litter anurans we constructed 154 plots of 5 x 5 m, being 77 of them in areas with jackfruit and 77 in areas with no jackfruit, totaling 3.850m of forest floor sampled. We collected a total of 613 frogs inhabiting the forest floor, being distributed within ten species: Brachycephalus didactylus; Chiasmocleis sp.; Haddadus binotatus; Ischnocnema guentheri; Ischnocnema otavioi; Ischnocnema parva; Leptodactylus marmoratus; Physalaemus signifer; Rhinnela ornata and Zachaenus parvulus. Six of this species were common to areas with and without jackfruit, and the similarity between the two areas was 60%. Areas with jackfruit had the double (N = 18) of plots with no amphibian. The number of amphibians recorded in plots with jackfruit (38%) was lower than the number found in areas without jackfruit (62%). The predominant amphibian species in both conditions was Ischnocnema parva, which had greater abundance in plots without jackfruit. The total density of frogs living on the forest floor in areas with jackfruit (12.2 ind/100 m) was lower than in areas without jackfruit (19.7 ind/100 m). Among the environmental parameters analyzed those with greater influence on the abundance of amphibians were the depth of leaf litter and soil pH. The data suggested that the addition of jackfruit, besides occupying the habitat of native species, is able to promote changes in the structure of these habitats that may intervene in the local fauna.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O processo de introdução de espécies é reconhecido como a segunda causa mais importante de erosão da diversidade biológica em muitos ambientes no Brasil e no mundo. As espécies invasoras possuem não apenas o poder de sobrevivência e adaptação em outros ambientes, mas a capacidade de dominar a diversidade biológica nativa através da alteração das características básicas dos processos ecológicos naturais e das interações. A jaqueira, Artocarpus heterophyllus Lamarck (Moraceae), tem sua origem nas florestas tropicais da Índia, tendo sido introduzida no Brasil ainda no período Colonial e atualmente é invasora em áreas de Mata Atlântica. Este estudo fornece os primeiros dados sobre a influência da espécie exótica invasora Artocarpus heterophyllus sobre comunidades de anuros de folhiço. As amostragens foram realizadas em uma área de Mata Atlântica, no litoral sudoeste do estado do Rio de Janeiro, incluindo informações sobre riqueza de espécies, densidades específicas e parâmetros ambientais. Nosso estudo foi realizado no Parque Estadual da Ilha Grande entre janeiro de 2009 e março de 2011. Para amostrar a comunidade de anuros de folhiço usamos 154 parcelas de 5 x 5 m, sendo 77 delas em áreas com jaqueiras e 77 em áreas sem jaqueiras, totalizando 3.850 m de chão de floresta amostrados. Nós amostramos um total de 613 anuros habitando o chão da floresta, pertencentes a dez espécies: Brachycephalus didactylus; Chiasmocleis sp.; Haddadus binotatus; Ischnocnema guentheri; Ischnocnema octavioi; Ischnocnema parva; Leptodactylus marmoratus; Physalaemus signifer; Rhinnela ornata e Zachaenus parvulus. Seis das dez espécies foram comuns às áreas com e sem jaqueiras, sendo a similaridade entre as duas áreas de 60%. As áreas com jaqueiras tiveram o dobro (N = 18) de parcelas sem nenhum anfíbio. O número de anfíbios registrados nas parcelas com jaqueiras (38%) foi menor do que o encontrado nas áreas sem jaqueiras (62%). O anfíbio predominante no folhiço em ambas às condições foi Ischnocnema parva, tendo abundancia maior nas parcelas sem jaqueiras. A densidade total de anuros vivendo no chão da floresta nas áreas com jaqueiras (12,2 ind/100 m) foi menor que nas áreas sem jaqueiras (19,7 ind/100 m). Entre os parâmetros ambientais analisados os que possuíram maior influência sobre a abundância de anfíbios foram a profundidade do folhiço e o pH do solo. Os dados sugerem que a jaqueira, além de ocupar o habitat de espécies nativas, é capaz de promover alterações na estrutura desses habitats que irão intervir na fauna do local. / The process of species introduction is recognized as the second most important cause of biological diversity erosion in many environments in Brazil and worldwide. Invasive species have not only the power to survive and adapt in other environments, but also the ability to master the native biodiversity by altering the basic characteristics of natural ecological processes and interactions. The jackfruit tree, Artocarpus heterophyllus Lamarck (Moraceae), has its origin in the tropical forests of India, being introduced in Brazil during the Colonial period and is currently invading the Atlantic Forest. In this study we provide the first data about the influence of the invasive alien species Artocarpus heterophyllus on anuran communities. Samples were taken in an area of Atlantic Forest, on the Southwest coast of the State of Rio de Janeiro, and included information on species richness, density and environmental parameters. Our study was conducted at the Ilha Grande State Park, between January 2009 and March 2011. To sample the community of litter anurans we constructed 154 plots of 5 x 5 m, being 77 of them in areas with jackfruit and 77 in areas with no jackfruit, totaling 3.850m of forest floor sampled. We collected a total of 613 frogs inhabiting the forest floor, being distributed within ten species: Brachycephalus didactylus; Chiasmocleis sp.; Haddadus binotatus; Ischnocnema guentheri; Ischnocnema otavioi; Ischnocnema parva; Leptodactylus marmoratus; Physalaemus signifer; Rhinnela ornata and Zachaenus parvulus. Six of this species were common to areas with and without jackfruit, and the similarity between the two areas was 60%. Areas with jackfruit had the double (N = 18) of plots with no amphibian. The number of amphibians recorded in plots with jackfruit (38%) was lower than the number found in areas without jackfruit (62%). The predominant amphibian species in both conditions was Ischnocnema parva, which had greater abundance in plots without jackfruit. The total density of frogs living on the forest floor in areas with jackfruit (12.2 ind/100 m) was lower than in areas without jackfruit (19.7 ind/100 m). Among the environmental parameters analyzed those with greater influence on the abundance of amphibians were the depth of leaf litter and soil pH. The data suggested that the addition of jackfruit, besides occupying the habitat of native species, is able to promote changes in the structure of these habitats that may intervene in the local fauna.

Les cours d’eau sont des vecteurs de dispersion efficaces pour les espèces végétales colonisant les berges, y compris pour celles qui ne sont pas a priori adaptées à ce mode de dispersion. Dans le cas d’espèces invasives, l’étude des traits de dispersion et de colonisation, et leur variabilité, permet la compréhension du potentiel de propagation d’une espèce dans son aire d’invasion et du potentiel d’adaptation à de nouveaux environnements. Le complexe invasif Fallopia est un taxon génotypiquement diverse qui colonise les berges. Son succès reposerait en partie sur la dispersion des propagules végétatives et sexuées. L'objectif de ce travail a été d’étudier les stratégies de dispersion par les cours d’eau, de ce taxon terrestre. Ce travail a permis de quantifier le potentiel de dispersion et de colonisation de Fallopia par l’étude de la flottaison et la viabilité en fonction de la durée d’immersion des propagules. Ce travail a montré que les rhizomes ne flottent pas contrairement aux tiges et aux akènes. La durée de flottaison est liée aux traits morphologiques. La germination des akènes dans l’eau peut allonger cette durée de flottaison. La durée d’immersion ne réduit la viabilité des propagules qu’à partir de 3 semaines. La variabilité observée des traits a permis d’identifier différentes stratégies de propagation du taxon en milieu aquatique. La régénération dans l’eau des tiges et akènes permet leur installation rapide sur le site du dépôt tandis que les rhizomes régénèrent qu’une fois sur le site de dépôt si les conditions sont favorables. Bien que la variation des traits des propagules soit continue entre les taches, il est possible d’identifier, en particulier sur les akènes, des individus ayant des aptitudes à la dispersion sur des longues distances, pouvant participer à la progression du front d’invasion du taxon. Ces résultats montrent que les capacités de dispersion et colonisation des propagules peuvent participer au succès de propagation du taxon par les cours d'eau / Watercourses are efficient dispersal vectors for plant species colonising riverbanks, including those that are not primarily adapted to this dispersal mode. In the case of invasive species, the study of plant traits participating to dispersal and colonization, and their variability, is important to understand the spread potential of one species in the invasive area, as well as its adaptive potential to new environments. The invasive complex Fallopia displays a high genotypic diversity and highly colonises riverbanks. Dispersal of sexual and vegetative propagules could explain their colonization success. The aim of this work is to study the dispersal strategies by watercourses displayed by this terrestrial taxon.This work has quantified the dispersal and colonization potential of Fallopia propagules through the study of their floatation ability and their viability after water exposure. This work demonstrated that rhizomes do not float unlike stem fragments and achenes. Floatability is related to morphological traits. Achene germination in water may increase the floatation time. Il was also demonstrated that viability was only reduced after 3 weeks of water exposure. The variability observed for the traits allows to identify different spread strategies in this taxon. Stem and achene regeneration in water enables a rapid installation in the riverbanks, while rhizomes regenerate after deposition in the riverbank, if environmental conditions are favourable to the development and the survival of the plant. Even if variability of propagule traits is continuous, it is possible to identify, in particular for achenes, individuals that have the capacity to disperse over long distances, and that could participate to the progression of the invasive front of the taxon. These results demonstrated that dispersal and colonization abilities of Fallopia propagules might participate to the spread potential of the species through watercourses