published_or_final_version / abstract / toc / Ecology and Biodiversity / Master / Master of Philosophy

Invasive exotic plant species have been recognized as serious threats to ecosystems. Extensive research on invasive exotic plant species has primarily focused on the impacts, characteristics, and potential treatments. Decision tools and management models that incorporate these findings often lack input from managers and have limited use in differing invasion scenarios. Therefore, in this study, I created a scientifically-driven framework that incorporates expert input to prioritize watersheds for management within the Inner Bluegrass region of Kentucky. The widely distributed invasive exotic plant Amur honeysuckle (Lonicera maackii) was used as an example species. The framework is built around the Analytic Hierarchy Process and highlights areas in most need of invasive exotic plant management by incorporating weighted landscape variables associated with the invasion process. Results of the prioritization provide useful information for natural resource managers by aiding in the development of control strategies while also creating a valuable framework that can be adapted to various invasive exotic plant species.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-10-18T14:30:50Z No. of bitstreams: 2 Dissertação - Cristiele Barbosa Valente - 2014.pdf: 1029577 bytes, checksum: ddb0057b71c64fb5c0213a752b6d73f3 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-10-18T14:31:35Z (GMT) No. of bitstreams: 2 Dissertação - Cristiele Barbosa Valente - 2014.pdf: 1029577 bytes, checksum: ddb0057b71c64fb5c0213a752b6d73f3 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-10-18T14:31:35Z (GMT). No. of bitstreams: 2 Dissertação - Cristiele Barbosa Valente - 2014.pdf: 1029577 bytes, checksum: ddb0057b71c64fb5c0213a752b6d73f3 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2014-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The invasion of terrestrial habitats by exotic plants often has negative effects on growth and fitness of native plants. Exotic plants may change the foraging behavior of pollinators and dynamics of interactions of local assemblages. Due to the lack of shared evolutionary history between exotic plants and native pollinators, it is likely that the morphological and phenological mismatches are especially important in determining the interactions involving exotic plants and specialist native pollinators. In addition, exotic plant species are expected to be pollinated by abundant generalist pollinators whose interactions are phylogenetically constrained compared to specialists pollinators. To evaluate these issues, we compiled 28 plant-pollinator networks with 778 plant species (10% alien) and 3019 pollinator species, comprising 7919 interactions. We expected that: (a) exotic plants tend to be visited by more generalist pollinator species compared to the co-occurring native plant species; (b) an increase in the proportion of exotic plants in the plant-pollinator networks promotesan increase in the global connectivity and nestednessof the interactions. If these predictions are correct, then the introduction of plants should also promote an increase in the risk of heterospecific pollen deposition on native plants. We found that exotic and native plants did not differ in the average degree of specialization of their pollinators. Moreover, an increase in the proportion of alien plants did not affecteither structure or the connectivity of networks. On the other hand, there was an increase in the risk of heterospecific pollen deposition on native plant stigmas when the proportion of exotic plants increases to about 1/3 of the flora pollinated by animals.However, above this percentage the relationship is reversed. This result may be a consequence of progressive decrease in pollinator fidelity of native plants in habitats with low-levels of invasion by exotic species, reducing the amount of shared pollen due to the impoverished pollinator fauna. / A invasão de habitats terrestres por plantas exóticas geralmente tem efeitos negativos sobre o crescimento e reprodução das plantas nativas. Além disso, plantas exóticas podem promover alterações no comportamento dos polinizadores e na dinâmica de interações das assembleias locais. Devido à ausência de uma história evolutiva entre plantas exóticas e polinizadores locais, é provável que as restrições morfológicas, fenológicas e comportamentais atuem de modo mais severo sobre interações envolvendo plantas exóticas e polinizadores nativos especialistas. Além disso, quando uma planta coloniza uma nova área, espera-se que ela interaja com maior probabilidade com os polinizadores generalistas devido, entre outros fatores, à maior abundância e menor seletividade dos mesmos. Assim, esperamos que: (a) em redes de interação planta-polinizador, os visitantes florais das plantas exóticas sejam mais generalistas do que aqueles que visitam plantas nativas; (b) a introdução de plantas exóticas promova um aumento na conectividade e no aninhamento das redes de interações planta-polinizador. Consequentemente, a introdução de plantas deve promover também um aumento no risco das plantas nativas receberem pólen heteroespecífico. Para avaliar as expectativas acima, compilamos 28 redes de interações planta-polinizador com 778 espécies de plantas (10% exóticas) e 3019 espécies de polinizadores, compreendendo 7919 interações. Em assembleias locais, as plantas exóticas e nativas não diferiram quanto ao grau de especialização de seus polinizadores. Além disso, um aumento na proporção de plantas exóticas não promoveu alterações na conectividade e estrutura das redes de interações. Por outro lado, há um aumento no risco das plantas nativas serem contaminadas por pólen heteroespecífico (Rphr) quando a porcentagem de plantas exóticas aumenta até atingir cerca de 13 da flora polinizada por animais. Isso pode ser uma consequência da diminuição na fidelidade dos polinizadores das plantas nativas em ambientes pouco invadidos. No entanto, acima desse percentual a relação é inversa, o que pode ser consequência da redução na quantidade de pólen compartilhado devido à perda de parte da fauna de polinizadores.

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

Hygrophila polysperma is a plant native to Asia that has been introduced into the Comal River, TX and is thriving while Ludwigia repens, a species native to the river appears to be declining. Both plants have similar morphologies and occupy similar habitats in the river. Two plant competition experiments were conducted to examine the competitive interactions between the two species. First, an experimental design was developed in which established Ludwigia plants were 'invaded' by sprigs of Hygrophila to determine if established Ludwigia populations would be negatively impacted by invasion. The second experiment focused on establishment and growth of sprigs of each species under three competition scenarios. Results show that the continued growth of well-established Ludwigia plants was significantly depressed by the invasion of Hygrophila in comparison with those that had not been invaded. Furthermore, the growth of Hygrophila sprigs was uninhibited by the presence of Ludwigia, but the presence of Hygrophila negatively impacted the growth of Ludwigia sprigs. There was no difference in the growth of Hygrophila sprigs whether planted alone, with Ludwigia sprigs or even if planted into stands of established Ludwigia.

For decades scientists believed that herbivory had minimal impact on freshwater ecosystems. We now know that herbivory in freshwater systems equals or exceeds herbivory in terrestrial and marine systems. In extreme cases, herbivores can change clear, macrophyte dominated ecosystems into turbid plankton dominated ecosystems. Even though research on plant-herbivore interactions in freshwater systems has increased, there is still much that is unknown. This thesis is comprised of four studies investigating freshwater plant-herbivore interactions across multiple spatial scales. The first study investigated how induced chemical defenses in Cabomba caroliniana suppress herbivore consumption and growth as well as how this herbivore-generated change in plant chemistry affects the growth of plant associated microbes. At the spatial scale of individual ponds or lakes, consumers that induce their host plants may also be indirectly affecting other consumers and microbial pathogens via changes in this shared resource. The second study moves to an ecosystem scale and investigates how exotic versus native apple snails may impact Everglades' habitats. We investigated plant preference, consumption, growth and conversion efficiencies in the singly native apple snail to occur in the U.S. (Pomacea paludosa) versus four introduced species (P. canaliculata, P. insularum, P. haustrum and P. diffusa). We found that even though plant preferences are similar, invasive snails tend to eat more, grow more rapidly, and sometimes more efficiently than natives. This suggests that invasive species could have a large impact on the environment, especially the abundance of submerged plants. The third study investigated how palatability of freshwater plants varies with latitude (i.e. geographic scale). Increased herbivory at lower latitudes is hypothesized to select for increased plant defenses, which has been shown to be true for tropical forests, salt marshes, and seaweeds. When we contrasted eight confamilial plants collected in Indiana versus Southern Florida, three of four herbivores significantly preferred northern plants. When we evaluated a second set of plants collected from Indiana versus Central Florida, only one of three herbivores preferred the northern plants. Overall, our results suggest a preference for northern plants, but the strength of this relationship was variable. We hypothesize that this variability may be driven by 1) local variance in herbivore pressure that creates variance in plant defenses, and/or 2) the effect of winter length on the survival and feeding rate of herbivores. The final study expanded to a world scale, and investigated herbivore preference for native vs exotic plants. We found that both N. American crayfish and S. American snails preferred exotic plants over confamilial natives, despite responding to different plant characteristics. The single species of apple snail that occurs in N. American showed no preference for native or exotic plants from a N. American perspective, but instead exhibited preferences that correlated with its history of evolution in S. America. As the N. American species is a sister species of the S. American snails, feeding by the N. American snail appears more affected by its S. American lineage than its recent history in N. America. This suggests that phylogenetic legacy will affect choices of the herbivore as well as resistance or susceptibility of plants.

This dissertation is an investigation into how plants provide a way to explore cultural interactions between Greece and Rome and the east. I use India, a region that remained consistently exotic to most Greeks and Romans throughout antiquity, as a test case to examine how eastern plants were received and integrated into Greek and Roman culture. Throughout I use my test case as a focus and as an object of comparison: India is a constant reminder of what was conceptualized as exotic. My methodology is primarily "plants in text," an approach that incorporates both the physical reality of plants for sale at the market as well as the imagined flora that grows at the end of the earth. The results of this inquiry show the value of investigating the cultural importance of plants and the mental constructs that surround them in the ancient Greek and Roman worlds. / The Classics

Biological invasions are driving environmental state changes on a global scale. Exotic plant species must be successful at passing several abiotic and biotic filters to establish and disrupt the native plant community assembly. Understanding where exotic plants are on a regional scale and being able to characterize how exotic plants are generally interacting with their environment is crucial information for exotic species management (chapter 1). In the western United States human-related activities are augmenting the spread of exotic plant species by increasing the ignitions of wildfire. Wildfire can lead to nutrient pulses through the removal of intact native communities and returning some mineral content into the soil. Exotic plant species that have traits that efficiently acquire nutrients accompanied by rapid growth rates may outcompete native plants. In chapters 2, 3, and 4 experimental fires demonstrated that the direct effect of fire may not be as critical as the potential indirect effects of fire such as altering the behavior of consumers (chapter 2) and reducing competition (chapters 3 and 4). In the Mojave desert, rodent consumers can have strong top-down effects on plant community assembly through foraging selection preferences. Life history traits such as seedling and seed size can lead to differential herbivory and positively benefit some plant species while inhibiting others (chapter 1) which could indirectly alter plant-plant interactions. Plant competition is a biotic filter than can determine establishment success or failure. Species that with rapid growth rates and plastic growth responses are likely to be able to capitalize on fluctuations in available resources. In the Great Basin, forecasts in climate change models predict that precipitation timing will lead to heavier fall rains and more rain than snow in the winter. Water availability is one of the main limiting factors in semi-arid and arid ecosystems where native plants have adaptive traits to maximize resource use. The interaction of wildfire and changes in climate, specifically timing of precipitation is critical to understand to be able to predict and protect against increasing wildfire frequency and severity. In chapter three, the responses by a key exotic annual grass, Bromus tectorum, and keystone native perennial shrub Artemisia tridentata subsp. wyomingensis, were positive for increased early fall precipitation but much more pronounced for B. tectorum. Exotic annual plants are able to respond to changes in timing of fall precipitation and have extreme growth which leads to superior competitive abilities through interference and priority effects (chapter 4). Native plants can compete with exotics but the magnitude of the effects are diminished compared to the negative interaction from exotics. Together these findings demonstrate that across several regions exotic annual grasses are capable of passing through abiotic filters and disrupting biotic interactions of the native plant community. This is likely to lead to increased spread of exotic annual species and may indicate potential and availability of fine fuel production supporting increases in size and frequency of wildfires in the western United States.

No description available.

Conserving the earth's precious water supply is of increasing importance in light of the growing population and climate dynamics; therefore, this study focuses on identifying those exotic species that are best suited for the changing climate and environment of the Lower Kanawha Valley Region in West Virginia without compromising the water sustainable qualities once exhibited by the indigenous species. This task was accomplished by reviewing, analyzing, and evaluating the plant hydraulics and habitat matching characteristics associated with the identified native and exotic species. These species were limited to those produced or found in the local nurseries and garden centers in the designated region, thereby providing a practical and water sustainable plant list for the local homeowners and design professionals. The final list of species was translated into a master planting design of an arboretum displaying and demonstrating water conservation on the grounds of the Hurricane Valley Park. / Department of Landscape Architecture