Over the last century anadromous alewife (Alosa psuedoharengus) and blueback herring (Alosa aestivalis), collectively called river herring, suffered drastic declines throughout their range from Newfoundland (Canada) to North Carolina (USA). A 2011 petition to include river herring in the Endangered Species Act (ESA) was rejected, partly due to inadequate information towards identifying coast-wide population status. Additionally, knowledge gaps were identified with basic ecology of the river herring life cycle in freshwater, including species reproductive strategies. In Chapter 2, I investigated how body size, spawning arrival time, and sex influence river herring reproductive success. I collaborated with the Massachusetts Division of Marine Fisheries to introduce adult river herring (421, 266, and 410 individuals in 2013, 2014, and 2015, respectively) into Pentucket Pond (Massachusetts, USA), which historically had river herring but is currently inaccessible to upstream migrants. Using fin clips from stocked adult fish and juveniles collected in the lake each summer, I genotyped individuals and constructed pedigrees with 15 microsatellites. River herring had small (mean =1.1) families and spawned multiple times with multiple mates from May to June. Females were more successful than males. Earlier arrival and larger body size were independent indicators of reproductive success. These results provide critical river herring life history information for the freshwater component of population models that will inform management of this at-risk species. Presently, most river herring populations are monitored using data from citizen counts of spawning adults entering freshwater. Involving citizen watershed groups in data collection and may provide ancillary benefits beyond collection of population-level count data. In Chapter 3, I used pre-and post-surveys to assess how involvement in one citizen monitoring program influenced participants’ environmental knowledge, attitudes, and behaviors. Participants began the program with high scores for broader scientific and pro-environmental attitudes and pro-environmental behaviors. After the program, participants reported increased connection to nature, citizen science involvement, river herring knowledge, and engagement in outdoor recreation. For participants, engagement with nature was the most important program benefit. These results provide an additional case study to the citizen science literature and demonstrate that citizen science programs can help participants connect with the environment.

In 2004, I initiated a year-long study to investigate the food habits of burrowing owls (Athene cunicularia). Burrowing owls have been found in a variety of human-altered landscapes; however, little is known about burrowing owl food habits in urban landscapes. Burrowing owl food habits during the non-breeding season are also largely undocumented, despite increasing concern over the survival of overwintering burrowing owls. Differences in prey consumption between reproductive and non-reproductive owls during the breeding season have not yet been examined. I collected pellets over a 12 month period at four study sites affected by different levels of human alteration in the southern San Joaquin Valley of California. Data was collected at four study sites representing natural (Wind Wolves), semi-natural (Allensworth Ecological Reserve), agricultural (Friant Kern Canal), and urban (Bakersfield) landscapes. Invertebrates, primarily ground dwelling insects, were the most commonly consumed prey type, found in 96% of all pellets examined. Among vertebrates, mammals were the most commonly consumed (18.5% of all pellets). Shannon-Weiner diversity indices identified differences in prey diversity consumed between seasons within each site and between sites within seasons, except during the breeding season where diversity was the same at all sites. The diversity indices at Wind Wolves (natural site) and Bakersfield (urban site) were the same, while the diversity indices at Allensworth Ecological Reserve (semi-natural site) and Friant Kern Canal (agricultural site) were the same. Binary logistic regression was used to determine if consumption of individual prey types varied by site, season, and a site/season interaction. Mammals were consumed in greater proportions during the breeding season at most sites compared to other seasons. The proportion of pellets containing mammals during the breeding season decreased as the level of human-alteration increased, with mammal consumption highest at Wind Wolves (60.0%) and lowest at Bakersfield (13.1%). Consumption of several insect categories differed by site and/or season (Coleoptera, Dermaptera, and Orthoptera), but overall consumption of insects was not different by either factor. To assess differences in prey consumption between reproductive and non-reproductive owls, pellets collected during the 2005 breeding season were classified as having come from a nest burrow or a non-nest burrow based on positive identification of reproduction. Shannon-Weiner diversity indices and binary logistic regression were calculated for this data set. No differences were detected in overall diversity or in the proportional consumption of individual prey categories. The results of this study indicate that burrowing owls have a highly variable diet and may have sufficient ecological plasticity to allow them to adjust their food habits to the prey species available in human-altered landscapes. However, the implications of altered food habits on burrowing owl fitness in heavily disturbed landscapes, particularly urban landscapes, needs further study.

The southern Appalachian Mountains have among the highest salamander diversity in the world, largely due to local speciation in the family Plethodontidae. Plethodontid salamanders (i.e., lungless salamanders) are particularly sensitive to habitat climate conditions due to their reliance on cutaneous respiration, and their immediate environmental conditions (microhabitat) likely influence their dispersion and activity more than the large-scale atmospheric conditions. The Northern Gray-cheeked salamander (Plethodon montanus) is restricted to high elevations in the Appalachian Mountains. Our goal was to investigate the relationship between P. montanus and its microhabitat by examining behavioral preference for climatic conditions, characterizing the microclimate with small-scale models, and testing for differences in stress hormones at different elevations. We found that behavioral preference is most restricted by relative humidity, microclimate models predicted far less prevalence at lower elevations than typical coarse-scale models, and stress hormones were elevated at a low elevation plot compared to a high elevation plot.

Crassostrea virginica, the eastern oyster, is a native keystone species that inhabits many coastal and estuarine ecosystems along the Atlantic seaboard. Introduction of the eastern oyster into estuarine areas with limited current populations is gaining popularity as a pro-active approach to improve estuarine water quality. In November 2014 and April 2015, a total of five pilot oyster reef treatments were deployed in Brevard County: bagged adult oysters (grown by community members under their docks through oyster gardening) collected in fall 2014 and spring 2015, bagged clean shell, oyster restoration mats, and empty plots (control). Locations of deployment included a Merritt Island impoundment (Marsh Harbor), Nicol Park (Port St. John), and Scout Island (Melbourne Beach). Prior to deployment, we collected morphometric data (shell length, weight) on all gardened oysters. Abiotic factors including salinity, air and water temperature, and wind speed were collected monthly. During quarterly sampling at each site, morphometric data were collected for all live oysters, surviving and newly recruited. Results show survival of gardened oysters and natural recruitment differed by and depended greatly on the within-site location of each reef. In areas with no recruitment and limited gardened oyster survival, regular deployment of gardened oysters is needed for long term success. In areas with natural recruitment, bagged, clean shell or oyster restoration mats are most successful. Future restoration sites should be tested prior to any large-scale oyster deployments.

Marine protected areas (MPAs) are increasing in popularity as a tool to manage fish stocks through conservation of entire habitats and fish assemblages. Quantifying the habitat use, site fidelity, and movement patterns of marine species is vital to this method of marine spatial planning. The success of these protected areas requires that sufficient habitat is guarded against fishing pressure. For large animals, which often have correspondingly large home range areas, protecting an entire home range can be logistically challenging. For MPAs to successfully protect large top predator species, it is important to understand what areas of a home range are especially important, such as breeding and feeding grounds. New technologies, such as acoustic telemetry, have made it possible to track marine animal movements at finer spatial and temporal scales than previously possible, better illuminating these spatial use patterns. This study focused on the movement patterns of great barracuda (n=35), an ecologically important top predator, around Buck Island Reef National Monument, a no-take MPA in St. Croix, U.S.V.I. managed by the National Park Service. As developing standardized methods for acoustic telemetry is still a work in progress, the first half of this study focuses on determining appropriate tools for generating home range size estimates for great barracuda and analyzing ecological parameters driving these results. The second half of this study focused on the use of network analysis to look at spatial divisions within individual home ranges and to compare individual to population level spatial patterns, as well as to generate a relative estimate of population density within the park. Barracuda within the park demonstrated high site fidelity to individual territories, but at the population level they consistently used all habitats within the array. Core use areas within home ranges were evenly distributed throughout all habitats monitored by the acoustic array, although movement corridors were detected along high rugosity reef structures. Greater population densities within the park indicate that density dependent behaviors may be influencing habitat use within the park, and suggest that barracuda are contributing high levels of top down pressure through predation within the park boundaries.

Mycorrhizal networks (MNs), or the networks of fungal mycelia that connect plants to each other, are vital in contributing to the well-being of ecosystems. They not only assist in the transport of nutrients across an ecosystem, but also help protect an ecosystem from disease and adverse conditions. However, more research into these networks is needed and modelling these networks as graphs can help us achieve this. By applying centrality analysis and performing k-core partitioning on these networks, we are able to identify the trees that are most important and central to a MN and observe the effects of removing these trees. We also perform random partitioning on these networks and compare the results to the k-core partitioning results. We found that these networks are fairly resilient to the removal of a single keystone individual, but this can disrupt the interconnectedness of a MN in a dry (xeric) moisture regime. We also found that these networks are less resilient to k-core partitioning. In a network of trees divided up by age cohorts, the maximal k-core subgraph contained a mix of trees that mostly belonged to older cohorts and were linked to one specific fungal genet. This could influence conservation efforts for not only a few older trees, but also some younger trees and potentially specific fungal genets. When removing the maximal k-core subgraphs for networks in dry (xeric) and moist (mesic) moisture regimes, the network became disconnected for the xeric graph and still somewhat connected for the mesic graph. So, mycorrhizal networks could possibly be more resilient to this k-core partitioning in an area where the soil is moist rather than dry.

Knowledge of sex allocation trade-offs with tree growth in insect-pollinated woody plants is limited, particularly in invasive plants. This study examined patterns of growth and reproductive investment in a North American invasive plant species, Triadica sebifera, I hypothesized that the energy limitations of smaller trees may result in the production of more male reproductive structures that are energetically less costly. Diameter at breast height was a significant predictor of seed and catkin mass and regression can describe these relationships across sites. Seed and catkin mass were positively correlated across sites. The relationship between the seed mass:catkin mass ratio and DBH was not significant, nor was seed mass:catkin mass and total investment. Results showed a significant positive relationship between total reproductive investment and tree size across sites. Seed mass:catkin mass ratio and reproduction investment showed substantial variation among individual trees of similar size within sites.

When new populations are first identified in a region there are multiple potential sources: introduction of a non-native species, extra-range expansion of a nearby population, or demographic growth of a previously unnoticed species. Red foxes were absent or rare in the mid-eastern portion United States until the late 1800s. Their origins potentially include natural population increase/expansion, translocations from Europe, and, eventually, 20th century fur farming. In this study I attempt to identify the relative impact of native expansion versus human mediated introductions of both colonial era European foxes and early 20th century fur-farm foxes on the establishment of red foxes in the mid-Atlantic region of the United States. I subsequently address the potential impacts of hybridization and nuclear introgression between previously separate sister taxa. Through analysis of mitochondrial DNA, I identified indigenous haplotypes, two European haplotypes, and fur-farm haplotypes; another set of haplotypes were potentially indigenous or native. In addition, I found European Y-chromosome haplotypes. Most European and fur-farm haplotypes were found near the densely human-populated coastal plain and Hudson River lowlands; most red foxes of the Appalachians and Piedmont had native eastern haplotypes. However, nuclear data does not support this division showing low genetic structure despite the broad geographic scale of our study area, attributable both to range expansion and admixture. Admixture has not had the same impact on the nuclear genome as it has in mitochondrial haplotypes leading to mito-nuclear discordance across the region. I also found evidence for differential patterns of expansion related to habitat. Specifically, the Appalachian Mountains acted as a corridor for gene flow from the northern native source into the southern Mid-Atlantic region

The importance of social behaviour is evident in human society, but there are both costs and benefits associated with cooperation and sociality throughout the animal kingdom. At what point do the benefits outweigh the costs, and when do selective pressures favour sociality and colonization over solitude and independence? To investigate these questions, we have focused on an anomalous species of spider, Anelosimus studiosus, also known now as the northern social spider. Throughout its broad range, A. studiosus is solitary and aggressive, but recently, colonies of cooperative and social individuals have been observed at northern latitudes. This leads to two research questions: 1) what characteristics differentiate the two variants behaviourally, and, 2) how are they different physiologically? Colonies and individuals were collected from multiple populations throughout the Tennessee River watershed area and maintained in a laboratory environment for quantitative and qualitative assessment of behavioural traits as well as specific neurochemical analysis by high performance liquid chromatography with electrochemical detection. After classifying individuals as social or aggressive, I looked at the influence of factors such as age, reproductive state, nutritional state, and time of day on behaviour and neurophysiology. I found correlations between social behaviours and serotonin, aggressive behaviours and octopamine (invertebrate counterpart of norepinephrine), and several other compounds associated with an increase or decrease in aggression. These studies combine techniques from multiple disciplines to contribute to the greater understanding of the proximate control of social and aggressive behaviours as well as factors influencing the evolution of sociality.

Water supplies in California are stretched to critical levels as a result of population growth, periodic drought, and climate change. The California legislature recognized that the best way to increase supply is to decrease demand so the Water Use Efficiency Senate Bill 7 (SBx7-7) was signed into law in 2009. The law requires water purveyors to reduce per capita water usage by 20% by the year 2020. To comply, water purveyors are searching for innovative ways to increase water conservation. A review of the literature has shown that many factors influence water consumption. However, the majority of household water consumption is attributable to outdoor landscaping, and traditional grass lawns have increasingly been targeted for conservation measures by municipalities. The purpose of this study was to determine if the receipt of a landscape rebate reduces water consumption. The theoretical frameworks for this study were Ajzen and Fishbein’s theory of reasoned action and theory of planned behavior. Archival data were collected and analyzed utilizing an ordinary least squares regression analysis. The analyses determined that there was a significant reduction in water consumption for customers who received a rebate but there was no significant difference in water consumption in the 24 months before and 24 months after receipt of a rebate. While the results were mixed, a robust water conservation program, including Cash-4-Grass rebates, can have a significant impact on water consumption. This study is expected to promote positive social change via empirical data that allows water professionals to encourage alternative methods for extending California’s water supplies.