The roles of spatial scale and landscape change in mediating predator effects on stream fish communities

Doctor of PhilosophyDivision of BiologyKeith B. GidoThe role of predators in ecosystems has not only intrigued and puzzled ecologists over time, but predators are charismatic icons of conservation whose status indicates threats of global change. Through habitat alteration and fragmentation, climate change, and species introductions, predation pressure has been altered globally through the loss of apex predators, introduction of predators, and changes in predator distributions and abundance. While we know predators can influence ecosystems through top-down processes, managing changes in predation pressure requires quantifying effects of predators at scales relevant to management and conservation. In lotic systems, scales relevant to management often span across drainage basins, so predator effects must be quantified across stream networks. Because lotic communities also respond to landscape change, understanding the role of predators across stream networks requires careful consideration of local and broad scale abiotic factors influencing both predators and prey. I combined simulated, experimental, and observational data to 1) assess sampling strategies to determine effects of landscape change on stream fish communities, 2) measure changes in predator consumption rates across spatial scales and the role of prey behavior in driving scaling relationships, and 3) quantify the relationship between the presence of predators and stream fish community structure while controlling for abiotic variability across stream networks. In chapter 2, I compared how the distribution of sample sites (completely random, highly skewed, or uniform distributions) across landscape gradients influenced variability in measured responses of stream fish community metrics. Strong responses (species richness) to environmental gradients were robust to sample distributions, but large sample size and uniform distributions of samples across gradients were necessary to quantify more complex ecological responses (community composition). In chapter 3, I conducted a mesocosm study to quantify differences in per capita consumption across different arena sizes and measured three aspects of prey behavior hypothesized to be important in driving consumption rates: aggregation, movement, and spatial overlap with predators. Per capita consumption was highest in the largest arena relative to the smallest. I hypothesize the positive relationship between consumption and spatial scale was driven by lower group vigilance because prey aggregated less in large arenas. In chapter 4, I compared fish community structure, including richness and abundance of species, at sites in which a predatory fish, largemouth bass (Micropterus salmoides), were present or absent. I first identified which abiotic factors, including both natural stream attributes and anthropogenic landscape changes, drove the presence of largemouth bass and stream fish community structure. I then controlled for important abiotic factors to determine relationships between largemouth bass and stream fish community structure. Richness was higher than predicted based on abiotic factors at sites where bass were present. Several species associated with small impoundments exhibited significant co-occurrence patterns with largemouth bass, likely driving the heightened richness at sites with bass. Complex ecological phenomena such as community responses to predators are difficult to measures, especially in the context of landscape change. These studies highlight the importance of thoughtful study design, the scale-dependence of biotic interactions, and challenges of quantifying responses to predators at scales relevant to conservation and management

How Does Lake Powell Water Storage Influence Release Temperatures and Grand Canyon Fishes?

Current Lake Powell reservoir operations for equalization and the Upper Basin drought contingency plan are articulated as target reservoir surface elevations and storage volumes. This analysis asks and answers the question how does water storage in Lake Powell influence release temperatures and Grand Canyon fishes

The Role of Hydrologic Regimes in Driving Morphologic Divergence and the Trait Compositions of Fish Assemblages

The hydrologic regime is an important determinant of the ecological integrity of a stream. Hydrologic regimes are defined by the magnitude, timing, frequency, rate of change, and duration of high and low flow events and capture long term patterns of variability and predictability of water movement in a stream. Flow regimes influence many aspects of the biophysical environment in lotic systems; therefore organisms have adapted to natural flow patterns. We investigated how fish have adapted to flow regimes at both a population and community level. In the first study presented in this thesis, we hypothesized fish exhibit phenotypic divergence to allow them to persist across gradients of hydrologic variability. We combined a comparative field study and mesocosm experiment to investigate the morphological divergence of Campostoma anomalom (central stonerollers) between streams characterized by highly variable, intermittent flow regimes and streams characterized by relatively stable, groundwater flow regimes and assessed the plastic effects of one component of flow regimes, magnitude (water velocity), on fish morphology. We observed differences in shape between flow regimes likely driven by differences in allometric growth patterns, but observed no morphologic plasticity. The second study included in this thesis investigated the relationships between fish traits and hydrologic metrics and determined how traits are spatially auto-correlated within a stream network. We observed complex relationships between fish traits and hydrology; some traits exhibited different responses in different flow regimes. Trait-hydrology relationships were the strongest in groundwater and runoff streams, but very weak in intermittent streams. Spatial factors described more variability in the distribution of fish traits than hydrologic metrics within and between flow regimes and different types of spatial auto-correlation structured trait patterns across flow regimes. Overall, the results of these studies support the implementation of environmental-flow standards and contribute new considerations to include in the development of ecological-flow relationships

Perceptions of the Engineering Curricula from Women and LGBTQIA+ Students

The National Science Foundation’s Revolutionizing Engineering and computer science Departments (RED) grant was awarded to the Civil and Environmental Engineering (CEE) Department at Midsized MidAtlantic University in 2016. This RED grant enables the institution to improve the inclusion of underrepresented and underserved engineering students over the course of five years. One of the ways our RED research team implemented this grant was to conduct climate surveys distributed to all engineering students to document students’ academic preparation and participation, feelings of otherness in the College of Engineering, engineering self-efficacy, sense of inclusion and belonging in the College of Engineering, and their commitment to engineering as a major and career. We also surveyed students’ perceptions of the inclusiveness of the engineering curricula. While extensive research has been done on female and sexual minority students’ perceptions of belongingness in engineering, fewer studies have looked at how these students view the engineering curricula. This paper describes the responses of women and sexual minorities from the 2018 survey. We found that when it comes to their perceptions of coursework, they (in comparison to classmates without these identities) are less comfortable sharing in class, less likely to think bias/discrimination polices are stated and reinforced, and more likely to feel that their experiences and interests are excluded from the engineering curriculum. Not only do they feel their own identity’s interests are excluded, they felt the curriculum more broadly excluded the interests, experiences, and achievements of racial/ethnic groups, disabled groups, and low-income groups. In other words, their status as minority students made them more attuned to exclusionary coursework, practices, and attitudes for other minority identities as well compared to their male and heterosexual peers. The paper will discuss ways in which the RED team is intervening to make the engineering curricula more inclusive for all groups of students, and discuss recommendations for other programs to implement

The importance of waterbirds as an overlooked pathway of invasion for alien species

The importance of waterbirds as vectors of aliens has been recognized since Darwin's time, yet research by pioneers has been forgotten during the development of modern invasion biology, which tends to overlook this means of dispersal. Waterbirds are ignored in databases of alien species and invasion pathways, making management and prevention of invasions more difficult. I summarize 22 studies that provide empirical evidence for the dispersal of alien plants and invertebrates by waterbirds in aquatic and terrestrial ecosystems, complementing 14 studies recently identified by Reynolds et al. (2015, Diversity and Distributions, 21, 744–754). Together, these studies provide empirical evidence for the dispersal of 79 alien plant species and eight alien invertebrates by waterbirds, including some of the worst aquatic invaders and the most widely distributed alien terrestrial plant species. Waterbirds known to be vectors include ducks, geese, swans, shorebirds, gulls, herons and rails. Aliens are usually dispersed after being ingested or becoming attached to plumage, bills or feet, but waterbirds also disperse alien species when making nests, when preying on other vectors such as fish, or even attached to leg rings. Whilst waterbirds may have a trivial role in explaining the arrival of alien species to new continents, they have a vital role in spreading aliens around once they get there. Greater focus on the role of waterbird vectors is essential if management of invasions is to be effective, and I make proposals for future research.Peer reviewe

The Implementation of Earth Jurisprudence through Substantive Constitutional Rights of Nature

To date, international processes associated with sustainable development have not led to an internationally legally binding framework that adequately addresses the challenges we face. Human influence on the planet has led to the adoption, although not universally accepted, of the term Anthropocene to define our new relationship with nature. This paper aims to look at the role and rule of law in the making of society and, more importantly, the arguments for a shift in the paradigm from an Anthropocentric ontology to a more Earth-centered one. We critique the current approach to sustainable development and environmental protection, review arguments on the Rights of Nature and explore the potential for the concept of Earth Jurisprudence building on current literature. In particular, the paper outlines that a constitutional right of nature is needed to address the challenges that we now face globally. To this end, we also examine in detail the case study of the constitution of Ecuador where the rights of nature have been codified. We outline some of the key issues involved in this proposed approach to new legal frameworks and make recommendations for future research

Switchgrass Leaf Area Index and Light Extinction Coefficients

Much of recent interest in biofuel species modeling has been for switchgrass (Panicum virgatum L.). Such modeling requires accurate simulation of light interception. We investigated the stability of the light extinction coefficient (k) in Beer’s Law with data from Temple, TX; Lincoln, NE; and Elsberry, MO. Variability in k values was not related to fraction of light intercepted, time of day, or incident solar radiation. Only the magnitude of leaf area index (LAI) showed a significant impact on the k value. Th e mean k value (−0.37) for the ‘Alamo’ switchgrass data at Temple was similar to the previously published k value (−0.33) and similar to Alamo k values in Nebraska (−0.38) and Missouri (−0.31). Compared to Alamo, other switchgrass cultivars had similar k values in Nebraska but were higher in Missouri. This study gave guidance as to which factors are important for quantifying k with Beer’s Law for light interception of switchgrass

Board # 139 : Rethinking Engineering Diversity, Transforming Engineering Diversity (REDTED)

The research project described in this paper is titled “Rethinking Engineering Diversity, Transforming Engineering Diversity (REDTED),” which is part of the National Science Foundation, Revolutionizing Engineering Department (RED) grants. The project is in its first year and therefore what is described in this paper will be a brief overview of the project and some of the work done during the first year. The proposed research is to explore how the representation of women and Underrepresented Minority (URM) students and historically underserved groups will be increased in an engineering department by deploying a multi-pronged approach. The approach includes curricular and extra-curricular reform, which is targeted at the Civil and Environmental Engineering (CEE) Department at Rowan University and includes: a) Radically changing admission standards to promote excellence; b) Enhancing the perception and understanding of diversity and equality among students, faculty and administrators to create a more inclusive environment; c) Developing Advocate and Allies Mentoring Program for first year, and transfer students; d) Transforming existing engineering curriculum of second and third year from a narrow sub-discipline based approach to a more inclusive, system-based approach; e) Enriching students’ aspirations by providing successful and diverse role models from industry and academia; and f) Developing a model for inclusion of diverse students. The study is unique in that the definition of diversity is expanded to include both visible and invisible aspects. It also takes a comprehensive approach in making engineering more appealing to a more diverse population while also making sure that the diverse students who do choose to pursue engineering find an inclusive and welcoming climate. The first year of the study has been devoted to building partnerships and developing a consistent message. In addition, surveys of students and faculty to get baseline data on the attitudes to inclusivity have also been conducted to inform the strategies to be employed. In addition, faculty workshops to begin the process of modifying the curriculum is also being conducted. In addition, the student peer mentoring program and its structure is also being developed and student workshops are being conducted to develop peer mentoring skills

An integrated photonics engine for unsupervised correlation detection

With more and more aspects of modern life and scientific tools becoming digitized, the amount of data being generated is growing exponentially. Fast and efficient statistical processing, such as identifying correlations in big datasets, is therefore becoming increasingly important, and this, on account of the various compute bottlenecks in modern digital machines, has necessitated new computational paradigms. Here, we demonstrate one such novel paradigm, via the development of an integrated phase-change photonics engine. The computational memory engine exploits the accumulative property of Ge2Sb2Te5 phase-change cells and wavelength division multiplexing property of optics in delivering fully parallelized and colocated temporal correlation detection computations. We investigate this property and present an experimental demonstration of identifying real-time correlations in data streams on the social media platform Twitter and high-traffic computing nodes in data centers. Our results demonstrate the use case of high-speed integrated photonics in accelerating statistical analysis methods

First-Generation College Students and Othering in Undergraduate Engineering

We have baseline data collected from a sample of all Rowan engineering students in 2015-6, and have analyzed the differences between first-generation engineering students (FGES) and non-first-generation engineering students (Non-FGES) with respect to (a) their perceptions of “otherness” in a variety of situations in engineering at Rowan (FGES do not perceive themselves as “other” in most situations); (b) their background in engineering-related subjects and extra-curricular activities in high school (FGES background differs from Non-FGES); (c) their satisfaction with various aspects of the engineering program at Rowan (there are few differences); (d) their self-confidence as engineers (there are some differences); and (e) their commitment to and belief in a future career in engineering (FGES are strongly committed to, and believe they have, a future in engineering)