Invasive plant species threaten native plant communities and inhibit efforts to restore disturbed landscapes. Surface coal mines in the Appalachian Mountains are some of the most disturbed landscapes in North America. Moreover, there is not a comprehensive understanding of the land cover characteristics of post- mined lands in Appalachia. Better information on mined lands' vegetative cover and ecosystem recovery status is necessary for implementation of effective environmental management practices. The invasive autumn olive (Elaeagnus umbellata) is abundant on former coal surface mines, often outcompeting native trees due to its faster growth rate. The frequent revisit time and spatial and spectral resolution of Landsat satellites make Landsat imagery well suited for mapping and characterizing land cover and forest recovery on former coal surface mines. I performed a multitemporal classification using a random forest analysis to map autumn olive on former and current surface coal mines in southwest Virginia. Imagery from the Operational Land Imager on Landsat 8 were used as input data for the study. Calibration and validation data for use in model development were obtained using high-resolution aerial imagery. Results indicate that autumn olive cover is sufficiently dense to enable detection using Landsat imagery on approximately 12.6% of the current and former surface coal mines located in the study area that have been mined since the early 1980s. The classified map produced here had a user's and producer's accuracy of 85.3% and 78.6% respectively for the autumn olive coverage class. Overall accuracy in reference to an independent validation dataset was 96.8%. These results indicate that autumn olive growing on reclaimed coal mines in Virginia and elsewhere in the Appalachian coalfields can be mapped using Landsat imagery. Additionally, autumn olive occurrence is a significant landscape feature on former surface coal mines in the Virginia coalfields. / Master of Science

付記する学位プログラム名: 社会を駆動するプラットフォーム学卓越大学院プログラム / 京都大学 / 新制・課程博士 / 博士(農学) / 甲第25317号 / 農博第2583号 / 新制||農||1104(附属図書館) / 学位論文||R6||N5489 / DGAM / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 北島 薫, 教授 小野田 雄介, 教授 井鷺 裕司 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

No description available.

Invasive exotic species threaten native biodiversity, alter ecosystem structure and function, and annually cost over $100 billion in the US alone. Determining the ecological traits and interactions that affect invasion success are thus critical for predicting, preventing, and mitigating the negative effects of biological invasions. Native herbivores are widely assumed to facilitate exotic plant invasions by preferentially consuming native plants and avoiding exotic plants. Here, I use freshwater plant communities scattered broadly across the Southeastern U.S. to show that herbivory is an important force driving the ecology and evolution of freshwater systems. However, native consumers often preferentially consume rather than avoid exotic over native plants. Analyses of 3 terrestrial datasets showed similar patterns, with native herbivores generally preferring exotic plants. Thus, exotic plants appear defensively nave against these evolutionarily novel consumers, and exotic plants may escape their coevolved, specialist herbivores only to be preferentially consumed by the native generalist herbivores in their new ranges. In further support of this hypothesis, a meta-analysis of 71 manipulative field studies including over 100 exotic plant species and 400 native plant species from terrestrial, aquatic, and marine systems revealed that native herbivores strongly suppressed exotic plants, while exotic herbivores enhanced the abundance and species richness of exotic plants by suppressing native plants. Both outcomes are consistent with the hypothesis that prey are susceptible to evolutionarily novel consumers. Thus, native herbivores provide biotic resistance to plant invasions, but the widespread replacement of native with exotic herbivores eliminates this ecosystem service, facilitates plant invasions, and triggers an invasional meltdown. Consequently, rather than thriving because they escape their co-evolved specialist herbivores, exotic plants may thrive because their co-evolved generalist herbivores have stronger negative effects on evolutionarily nave, native plants.

Aquatic plants play an important role in the survival and proliferation of invertebrates in freshwater ecosystems. Exotic plants are now common in North American lakes and rivers, where they may displace native plants, thereby potentially altering epiphytic invertebrate communities. Differences in aquatic invertebrate communities on native and exotic plants are examined here through (1) a meta-analysis of published data, and (2) two field surveys in northeastern North America that compared invertebrates on the exotic Myriophyllum spicatum and Potamogeton crispus to those on their native congeners. The meta-analysis revealed that exotic plants generally support lower invertebrate abundance than do natives, while invertebrate taxa richness tends to be similar on exotic and native plants. The field surveys demonstrated that M. spicatum and P. crispus support significantly different invertebrate densities and lower taxa richness than their structurally similar native congeners. These results suggest that the replacement of native plants by exotics---even those with similar morphology---may cause concomitant changes to aquatic ecosystems.

This study focuses on the vegetation of the African city of Bujumbura, Burundi. Urban flora is detailed according to the origin of the species (native or introduced), their life form, the use of these species by the local population and their behaviour (invasive or not). <p>The correlation between different natural and anthropogenic environmental factors and the composition of plant communities has been demonstrated through the analysis of vegetation plots. Three types of green areas were studied: spontaneous vegetation on terra firma, wetlands <p>and domestic gardens.<p><p>The main ecological factor correlated to the composition of the spontaneous vegetation of terra firma is the degree of urbanization. From the suburb to the city centre, savannah species typical for the region are replaced by alien invasive species, mostly ruderals. The latter generally have a large distribution, often on several continents. The physiognomy of the vegetation also changes, with hemicryptophytes and phanerophytes in the outskirts and the dominance of therophytes and chamaephytes in the city centre.<p><p>In most of wetlands, a large proportion of the plant species are natives, but some wetlands are almost totally invaded by alien species. Soil type is the main environmental factor correlated with <p>the variability of the vegetation.<p><p>The flora of domestic gardens is mainly composed of introduced species used as ornamental, food or medicinal plants. The socio-economical status of the neighbourhood is the main factor correlated with the variability of the garden flora. In high standing neighbourhoods, most species are onamental, with many trees and shrubs. In popular neighbourhoods, the flora is mainly utilitarian (vegetables and fruits), with a significant proportion of native species, and composed mainly of annual species. <p>A small proportion of the alien species cultivated in gardens has become invasive in the semi-natural vegetation of the city and its surroundings. Many other species cultivated in the gardens could become invasive, based on their ecology and their invasive behaviour in other regions with a climate similar to that of Bujumbura.<p><p>Overall, the city of Bujumbura has a diverse flora, with many useful species (vegetables and fruits, traditional medicine, construction of fences and roofs, material for mats and art objects.). The vegetation also hosts wildlife: birds, fishes, hippos, crocodiles etc… <p><p>In conclusion, the vegetation of Bujumbura contributes to biodiversity conservation and provides services to the urban population, but the expansion of alien invasive species and the consequent homogenization of the vegetation is a challenge for the future.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

This dissertation examines nursery/garden centre compliance with Invasive Alien Plant (IAPs) legislation in eThekwini and uMsunduzi, South Africa. Despite South African governmental programmes, an apparent lack of public awareness regarding IAPs persists. The cost to clear IAPs in South Africa is estimated to be 12 billion Rand over 20 years. Nurseries/garden centres should be able to increase customer awareness of IAPs. However, Government regulation/instruction of nurseries/garden centres seems inadequate. A mixed methods approach involving quantitative and qualitative analyses of questionnaires, observations and interviews was used in this study. There was little evidence that nurseries/garden centres stocked/sold CARA plants. However, they were stocking/selling NEMBA plants in spite of knowing CARA, NEMBA and indigenous alternatives. There is little interaction with relevant government/industry programmes. It is recommended that the Department of Environmental Affairs institute a IAPs Advisory Committee to see to the dissemination and provision of relevant information and training concerning IAPs to the industry.

Thesis (PhD (Conservation Ecology and Entomology))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Natural and semi-natural ecosystems and human communities worldwide are under siege from a growing number of destructive invasive alien species. Alien species are those whose presence in an area is due to intentional or accidental introduction as a result of human activities. Some alien species become invasive, and some cause tremendous destruction to the ecosystem and their stability, but we do not yet understand fully the many factors that determine the levels of invasiveness in alien species. However, management of alien plants requires a detailed understanding of the factors that make them invasive in their new habitat. The aim of this study was to explore in detail the processes and potential for invasion of Schinus molle (Peruvian pepper tree) into semiarid savanna in South Africa and to examine the potential for this species to invade further in these ecosystems, and in other South African biomes. In this thesis I explored the patterns and processes of invasion of S. molle in semiarid savanna using small-scale experiments to investigate physical and ecological barriers to invasion that prevent or accelerate the invasion of this species. I examined factors such as pollination; seed production; seed dispersal; seed predation and viability, all known to contribute to invasiveness. I highlighted the critical role of microsite conditions (temperature, humidity, water availability) in facilitating S. molle seedling establishment in semi-arid savanna and demonstrated that microsite type characteristics need to be considered for management and monitoring of the species in South Africa. I demonstrated the ability of S. molle to out-compete indigenous woody plants for light and other resources and also showed that disturbance of natural ecosystems was not a prerequisite for invasion, although human activities such as tree planting have played a major role in disseminating this species in South Africa. Predicting the future distribution of invasive species is very important for the management and conservation of natural ecosystems, and for the development of policy. For this reason, I also assessed the present and potential future spatial distribution of S. molle in South Africa by using bioclimatic models and a simulation-based spread model. I produced accurate profiles of environmental conditions (both biophysical and those related to human activities) that characterize the planted and naturalized ranges of this species in South Africa, by linking species determinants, potential habitat suitability and likely spread dynamics under different scenarios of management and climate change. All those components provided insights on the dynamics of invasions by fleshy-fruited woody alien plants in general, and on S. molle invasions in South Africa in particular. I developed a conceptual model that described S. molle population dynamics leading to an understanding of the processes leading to the invasive spread of this species in South Africa. This work also emphasized the need for policy review concerning the invasive status of S. molle in South Africa, and recommendations are made for future research. / AFRIKAANSE OPSOMMING: Die natuurlike and half-natuurlike ekosisteme sowel as menslike gemeenskappe wereldwyd word bedreig deur ‘n groeiende hoeveelheid indringerplantspesies. Indringerplantspesies (daardie spesies wie se teenwoordigheid toegeskryf kan word aan opsetlike of toevallige inbringing deur menslike toedoen) is ‘n bedreiging nie net vanweë die massiewe verwoesting van die ekosisteme en ekosisteemstabilitiet nie, maar ook omdat ons nog nie ten volle verstaan hoe hulle van skaars in hul natuurlike omgewing tot dominant in hul nuwe habitat gaan nie. Bestuur van indringer plante vereis ’n begrip van biologise en ekologiese faktore wat lei tot hulle indringing in die nuwe habitat. Die primêre doel van hierdie studie was om in detail uit te vind wat die prosessesse en potensiaal is vir die indringing van S. molle (die Peruviaanse peper boom) in droë savanna en om indringingspatrone in droë savanna met huidige en potensieële toekomstige patrone in ander Suid-Afrikaanse biome te vergelyk. In hierdie tesis ondersoek ek die patrone en prosesse wat verband hou met die indringing van S. molle in droë savanna deur gebruik te maak van kleinskaalse eksperimente om fisiese en ekologise hindenisse te ondersoek wat indringing van S. molle in Suid-Afrika voorkom of versnel. Dit sluit faktore in wat bekend is om by te dra tot indringing van plant spesies, soos bestuiwing, saadproduksie, saadpredasie en kiemkragtigheid. Ek het die kritieke rol beklemtoon van mikroomgewingskondisies (temperatuur, humiditeit, waterbeskikbaarheid) in die fasilitering van S. molle saailingvestiging in droë savanna en het gedemonstreer dat die tipe mikroomgewingskarakteristieke in ag geneem moet word by betuur en monitering van die verspreiding van S. molle in Suid-Afrika. Ek het die vermoë van S. molle om inheemse plante te uitkompeteer gedemonstreer, en het gewys dat versteuring van natuurlike ekosisteme nie ’n voorvereiste vir S. molle indringing was nie, hoewel menslike aktiwiteite soos boomaanplantings ’n groot rol speel deur by te dra tot indringing van hierdie spesie in Suid-Afrika. Voorspelling van toekomstige verspreiding van indringerspesies is baie belangrik vir die bestuur en bewaring van natuurlike ekosisteme, sowel as vir ontwikkeling van wetgewing. Daarom is die huidige en potensiele toekomstige ruimtelike verspreiding van S. molle in Suid-Afrika bereken deur inkorporering van bioklimaatsmodelle en simulering gebasseer op ’n verspreidingsmodel. Ek het derhalwe akkurate profiele van omgewingstoestande (beide fisiese en daardie wat verband hou met menslike aktiwiteite) wat die aangeplante en natuurlike omvang van die spesie in Suid-Afrika kenmerk geproduseer deur spesiedeterminante, potensieële geskiktheid van habitatte en moontlike verspeidingsdinamika onder verskillende bestuursscenarios en kimaatsverandering te koppel. Al hierdie komponente verskaf insig in die dinamika van die indringing van houtagtige plante met vlesige vrugte oor die algemeen en S. molle in besonder in Suid- Afrika. Hierdie werk beklemtoon ook die behoefte vir hersiening van beleidsrigtings wat betrekking het op die indringerstatus van S. molle in Suid-Afrika en maak aanbevelings vir toekomstige navorsing.

The Brazilian pepper tree (BP, Schinus terebinthifolius), introduced to the United States in the 1800s, has since become a category one invasive plant in Florida, aggressively spreading to 3000 km2 of prime habitat. There is a serious dearth of knowledge on whether the rhizobiome plays any roles in the displacement of native flora and the range expansion of BP. This thesis discusses the well-established plant invasion mechanisms of the BP and highlights key emerging mechanisms and gaps in (a) the current understanding of the molecular, below-ground processes of BP invasion and (b) studies on the potential role of microbial interactions in the success of BP invasion already established for other select invasive species, and the intervention of soil metagenomic studies to elucidate plant invasive mechanisms. These poorly studied mechanisms could further explain the aggressive spread and resilience of BP and contribute significantly to the development of effective and sustainable control measures, enabling appropriate strategies for restoring native plants. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Resumo parte 1: A invasão biológica é uma das principais ameaças à biodiversidade em todo o mundo. Entretanto, apesar dos trópicos concentrarem a maior parcela desta diversidade, ainda é pouco e esparso o conhecimento científico disponível sobre plantas invasoras nos ecossistemas tropicais. Este capítulo tem como objetivo comparar a quantidade de trabalhos publicados sobre invasões biológicas por plantas terrestres em ambientes tropicais e não tropicais, assim como a abordagem seguida nesses artigos. Foram lidos, selecionados e revisados os artigos publicados no intervalo de 1995 a 2004, em oito revistas científicas de alto índice de impacto. Ao todo, foram encontrados 239 artigos sobre plantas invasoras, sendo que a maioria deles aborda ecossistemas da América do Norte e Europa. Este é um reflexo do desequilíbrio na produção científica atual, que não dá a devida atenção aos ambientes com a maior biodiversidade, sendo que esta recebe vários tipos de ameaças à sua conservação. Resumo parte 2: As palmeiras da espécie Archontophoenix cf. cunninghamiana são invasoras em um pequeno fragmento florestal na região metropolitana da cidade de São Paulo (SP). Este trabalho investigou a abundância das sementes dessa espécie na chuva e no banco de sementes nesse local. Foram coletadas cinqüenta amostras de solo e de sementes da chuva de sementes em doze coletas mensais. Os resultados indicam que a dispersão de sementes dessa espécie invasora é efetiva na mata e que há a possibilidade dessa espécie formar um banco de sementes sazonal. Portanto, o sucesso da invasão poderia ser explicado pela capacidade de dispersão dessa espécie na mata, assim como por outras características da espécie e pela baixa resistência à invasão da comunidade neste fragmento. / Biological invasion is one of the worst threats to the world biodiversity. The actual extent of the impact of biological invasions in the tropics is still unknown. The aim of this chapter is to survey the literature published on plant invasions, comparing the material concerning the tropics with that regarding the rest of the world. 239 articles published in 8 ecological journals over the past ten years were reviewed. Most of them focused on temperate ecosystems, in North America and Europe. There is a weak effort on research concerning plant invasions in tropical ecosystems. Much more research is needed to evaluate the real scenario in the countries that contain the highest biodiversity of the world. The exotic palm Archontophoenix cf. cunninghamiana invaded a small forest fragment in São Paulo (São Paulo, Brazil). The abundance of this species in the seed rain and seed bank were investigated. The results indicate that this species may form a seasonal seed bank in the soil and that the seed dispersal is effective in the community. The success of the invasion by this exotic palm can be attributed to its high dispersal ability and to the community high invasibility due to the isolation of the forest fragment.