UMD Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/3
New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.
More information is available at Theses and Dissertations at University of Maryland Libraries.
Browse
3 results
Search Results
Item EFFECTS OF THE INVASIVE PHRAGMITES AUSTRALIS ON THE PREDATION OF MOSQUITOES THROUGH CHANGES IN HABITAT COMPLEXITY(2019) Weeks, Virginia Lynn; Leisnham, Paul; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Ephemeral stormwater ponds in the eastern United States are often invaded by non-native Phragmites australis which has been associated with numerous negative impacts on resident systems, including changes in hydrology, displacement of native macrophytes, and degradation of wildlife habitat. Few studies have documented the impacts of invasive P.australis on macroinvertebrate communities. Vegetated edges of stormwater retention facilities are often important developmental habitat for medically significant mosquitoes and the invertebrate predators that regulate their abundances. The displacement of resident macrophytes by P.australis could alter the physical structure of pond vegetation and disrupt the interactions between mosquitoes and their visual predators. The overall goal of my thesis was to evaluate differences in habitat complexity between native macrophytes, T.latifolia and J.effuses, and P.australis, and explore how those differences may impact predation of mosquitoes. I addressed this goal by conducting a controlled laboratory predation experiment and field surveys of four stormwater ponds.Item Spatio-temporal mechanisms of urban mosquito coexistence in Baltimore, MD(2019) Saunders, Megan Elizabeth Maria; Leisnham, Paul T.; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Understanding the interactions governing species distributions and community structure are of fundamental ecological importance. Mosquitoes that utilize container habitats at their larval stage usually engage in strong competition and competitive exclusion is expected; however, numerous container-utilizing mosquito species co-occur in the same individual container habitats and regionally coexist. I investigated spatial and temporal mechanisms governing the distributions and abundances of the competitively superior invasive Aedes albopictus and resident Culex spp. mosquitoes in four neighborhoods with varying socioeconomic status in Baltimore, Maryland. Specifically, I investigated if the findings from both field surveys and field and laboratory experiments were consistent with four spatial and temporal hypotheses for species coexistence that act at different scales: spatial partitioning among neighborhoods and blocks, seasonal condition-specific competition, aggregation among individual container habitats, and priority colonization effects within individual containers. I found modest but important evidence for all hypotheses that could each facilitate Culex spp. coexistence with Ae. albopictus. I found clear neighborhood effects, with low SES neighborhoods supporting higher abundances of mosquitoes than high SES neighborhoods overall, but with the highest abundances of Ae. albopictus in low SES neighborhoods and Culex spp. being more variable among neighborhoods. Culex spp. abundances were higher in the early summer compared to mid-summer peaks in abundance for Ae. albopictus. Laboratory competition trials showed increased aggregation of Ae. albopictus had a slight positive effect on Culex spp. population performance, and aggregation conditions sufficient for coexistence among experimentally placed ovitraps and negative associations of Aedes and Culex genera in resident containers in the field. Lastly, I found that priority colonization of a container leads to stronger population performance for both species, and that resource availability seems to affect Culex spp. more than competition. The results of my dissertation have revealed the role of several ecological mechanisms that may facilitate the regional coexistence of Culex spp. with Ae. albopictus and is among the first bodies of work to do so. Due to their roles in the transmission of human pathogens, future examination of other spatial and temporal mechanisms of coexistence between Ae. albopictus and resident Culex spp. is warranted.Item KNOWLEDGE, ATTITUDES, AND IMPLEMENTATION OF BMPS AND MOSQUITO MANAGEMENT ACROSS A SOCIOECONOMIC GRADIENT(2017) Maeda, Potential Kanoko; Leisnham, Paul T.; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)To reduce nutrient pollution in our waterways and restore impaired watersheds, residents are needed to voluntarily practice a range of stormwater best management practices (BMPs). The overall goal of my thesis was to better understand barriers to BMP implementation by exploring the links among resident demographics, knowledge, and behaviors, as well as mosquito management, so that appropriate education can be more effectively developed and targeted. Importantly, this study found respondents who defined themselves as Caucasian or other races, and that were in owned houses, had higher mean BMP knowledge than respondents that identified themselves as African American and who are renters, respectively. This study also found that one barrier to BMP implementation, concern of mosquito breeding in BMPs, was not significant. Estimated abundances for all mosquito abundance metrics were significantly higher in combined other types of wet containers compared to wet disconnected downspouts, a commonly found BMP.