Location and Species Matters: Variable Influence of the Environment on the Gene Flow of Imperiled, Native and Invasive Cottontails

The environment plays an important role in the movement of individuals and their associated genes among populations, which facilitates gene flow. Gene flow can help maintain the genetic diversity both within and between populations and counter the negative impact of genetic drift, which can decrease the fitness of individuals. Sympatric species can have different habitat preferences, and thus can exhibit different patterns of genetic variability and population structure. The specialist-generalist variation hypothesis (SGVH) predicts that specialists will have lower genetic diversity, lower effective population sizes (Ne), and less gene flow among populations. In this study, we used spatially explicit, individual-based comparative approaches to test SGVH predictions in two sympatric cottontail species and identify environmental variables that influence their gene flow. New England cottontail (Sylvilagus transitionalis) is the only native cottontail in the Northeast US, an early successional habitat specialist, and a species of conservation concern. Eastern cottontail (S. floridanus) is an invasive species in the Northeast US and a habitat generalist. We characterized each species’ genomic variation by developing double-digest Restriction-site Associated DNA sequence single nucleotide polymorphism markers, quantified their habitat with Geographic Information System environmental variables, and conducted our analyses at multiple scales. Surprisingly, both species had similar levels of genetic diversity and eastern cottontail’s Ne was only higher than New England cottontail in one of three subregions. At a regional level, the population clusters of New England cottontail were more distinct than eastern cottontail, but the subregional levels showed more geographic areas of restricted gene flow for eastern cottontail than New England cottontail. In general, the environmental variables had the predicted effect on each species’ gene flow. However, the most important environmental variable varied by subregion and species, which shows that location and species matter. Our results provide partial support for the SGVH and the identification of environmental variables that facilitate or impede gene flow can be used to help inform management decisions to conserve New England cottontail.

Environmental drivers of the abundance and distribution of forage fishes on the Northeast US shelf, with a particular emphasis on northern sand lance

Small pelagic fishes, also termed forage fishes, represent a critical link between secondary production and myriad top predators in marine ecosystems, including the Northeast US shelf. In this dissertation, I analyze the drivers of forage fish distribution throughout the Northeast US shelf and the drivers of the abundance of the ecologically important northern sand lance. Chapter 2 examines the basic ecology of northern sand lance and uses these insights to identify mechanistic drivers of their abundance. I then explore different scenarios of these drivers to project sand lance abundance through the end of the 21st century, which appears precarious for adult sand lance unless current trajectories change. Chapter 3 analyzes the environmental drivers of the distribution of the six dominant, offshore forage fish species (northern sand lance, Atlantic herring, alewife, blueback herring, Atlantic mackerel, and Atlantic butterfish) on the Northeast US shelf to elucidate the role of environmental covariates in shelf occupancy by these taxa. The results of this chapter indicate shelf occupancy of butterfish and Atlantic mackerel are increasing through time while occupancy of sand lance is decreasing with time. The occurrence of most of these species is also moving deeper and northward with time. Chapter 4 assesses the source-sink dynamics of three sand lance hotspots through Lagrangian particle tracking models simulating larval sand lance transport. Connectivity varies among these hotspots with Georges Bank and Stellwagen Bank having notable retention while the Great South Channel relies on larvae from other hotspots. Retention on Stellwagen Bank and Georges Bank are linked to strong wind events during the larval period of sand lance. Collectively, this dissertation improves our understanding of the dynamics driving variability in the Northeast US shelf forage fish complex, particularly for northern sand lance.

Between Basilea and Utopia: Exploring the Impact of Kingdom Theology in US Latinx Pentecostalism

This article is a general exploration of US Latinx Pentecostalism’s explicit and implicit theology of the Kingdom of God and how it can contribute to US Latinx Pentecostalism’s socio-political engagement. An overview will be provided of traditional, US Pentecostal Kingdom theology and Kingdom theology in Latin American Liberation Theology. These will be contrasted with US Latinx Pentecostal perspectives. To locate US Latinx Pentecostal theology of the Kingdom of God, this paper will first provide a wide-ranging description of a traditional evangelical hermeneutical process. Afterward, an understanding of the Kingdom that is generally taught and accepted in most evangelical contexts will be discussed. This will be followed by a survey of dominant US Pentecostal theology of the Kingdom of God through the lens of the Assemblies of God doctrinal statements and Pentecostal scholars. The life and work of various Pentecostal ministers and author Piri Thomas will provide a Kingdom perspective of US Latinx Pentecostal practitioners. I will provide an analysis based on their life experiences and some of their writings. The writings of Orlando Costas will set the stage in order to examine the works of other US Latinx Pentecostal scholars. Thereafter, the theologies of Latin American Liberation Theologians Clodivis and Leonardo Boff and others will be surveyed. Before concluding, the article will provide a historical overview of Latinx Pentecostal social engagement in the northeast US with the goal of identifying Kingdom values and priorities.

Four distinct Northeast US heat wave circulation patterns and associated mechanisms, trends, and electric usage

Northeastern US heat waves have usually been considered in terms of a single circulation pattern, the high-pressure circulation typical of most heat waves occurring in other parts of the world. However, k-means clustering analysis from 1980–2018 shows there are four distinct patterns of Northeast heat wave daily circulation, each of which has its own seasonality, heat-producing mechanisms (associated moisture, subsidence, and temperature advection), and impact on electricity demand. Monthly analysis shows statistically-significant positive trends occur in late summer for two of the patterns and early summer for a third pattern, while the fourth pattern shows a statistically significant negative trend in early summer. These results demonstrate that heat waves in a particular geographic area can be initiated and maintained by a variety of mechanisms, resulting in heat wave types with distinct impacts and potential links to climate change, and that pattern analysis is an effective tool to distinguish these differences.

The Seasonal Microbial Ecology of Plankton and Plankton-Associated Vibrio parahaemolyticus in the Northeast US

Microbial ecology studies have proven to be important resources for improving infectious disease response and outbreak prevention. Vibrio parahaemolyticus is an ongoing source of shellfish-borne food illness in the Northeast, United States and there is keen interest in understanding the environmental conditions that coincide with V. parahaemolyticus disease risk to aid harvest management and prevent further illness. Zooplankton and chitinous phytoplankton associate with V. parahaemolyticus dynamics elsewhere, however, this relationship is undetermined for the Great Bay estuary (GBE), an important emerging shellfish growing region in the Northeast, US. A comprehensive evaluation of the microbial ecology of V. parahaemolyticus associated with plankton was conducted in the GBE using three years of plankton community, nutrient concentration, water quality and V. parahaemolyticus concentration in plankton data. The concentrations of V. parahaemolyticus associated with plankton were highly seasonal and the highest concentrations of V. parahaemolyticus cultured from zooplankton occurred approximately one month before the highest concentrations of V. parahaemolyticus from phytoplankton. The two V. parahaemolyticus peaks corresponded with different water quality variables and a few highly seasonal plankton taxa. Importantly, V. parahaemolyticus concentrations and plankton community dynamics were poorly associated with nutrient concentrations and chlorophyll-a, commonly applied proxy variables for assessing ecological health risks, and human health risks from harmful plankton and V. parahaemolyticus elsewhere. Together, these statistical associations (or lack thereof) provide valuable insights to characterize the plankton-V. parahaemolyticus dynamic and inform approaches for understanding the potential contribution of plankton to human health risks from V. parahaemolyticus for the Northeast US. IMPORTANCE The Vibrio-plankton interaction is a focal relationship in Vibrio disease research; however, little is known about this dynamic in the Northeast, US where V. parahaemolyticus is an established public health issue. We integrated phototactic plankton separation with seasonality analysis to determine the dynamics of the plankton community, water quality and V. parahaemolyticus concentrations. Distinct bimodal peaks in the seasonal timing of V. parahaemolyticus abundance from phyto- vs zooplankton and differing associations with water quality variables and plankton taxa highlight that monitoring and forecasting approaches should consider the source of exposure when designing predictive methods for V. parahaemolyticus. Heliotheca tamensis has not been previously reported in the GBE. Its detection during this study provides evidence of the changes occurring in the ecology of regional estuaries and potential mechanisms for changes in V. parahaemolyticus populations. The Vibrio monitoring approaches can be translated to aid other areas facing similar public health challenges.