Environmental Indicators and Impact Assessment Commons^™

Interannual Variation Of Ichthyofaunal Utilization Of A Man-Made Salt Marsh Creek In Mission Bay, California, Maria Angst

McNair Summer Research Program

Southern California’s wetlands are drastically declining due to human activities. Increasingly, marsh restoration and creation are being used to mitigate such losses. This study used minnow traps to resample the ichthyofauna of a created marsh (Crown Point Mitigation Site; CPMS) and an adjacent natural marsh (Kendall Frost) in Mission Bay, California, 26 years following the marsh creation. These data were compared to data collected from 1995-1998, immediately after marsh creation, and data from 2021. Fishes captured included Fundulus parvipinnis, Gillichthys mirabilis, Acanthagobius flavimanus, Ctenogobius sagittula, and Mugil cephalus. Species richness and dominance measures were higher in the natural relative to …

Identifying Key Stream Restoration Variables In An Agriculturally Impaired Chesapeake Bay Watershed, Julia Portmann

Masters Theses, 2020-current

The Chesapeake Bay watershed spans several states, supports diverse ecosystems, and is crucial to local economies. However, agricultural practices in this region impair water quality. The Smith Creek watershed, within the Shenandoah Valley, was designated a showcase watershed in 2010 by the United States Department of Agriculture to demonstrate the efficacy of implementing restoration projects. We sampled fifteen farms ranging from unrestored to thirty-six years since restoration. At each site, we conducted a kick-net survey for macroinvertebrates, measured canopy cover, algal density, substrate size, and bank height and angle. We identified macroinvertebrates to family and calculated the Chesapeake Basin-wide Index …

The Effect Of Different Feeding Regimes On Recent Nutritional And Growth Measurements In Juvenile California Killifish (Fundulus Parvipinnis), Emily Parks

Theses

Gaining a deeper understanding of in-situ growth approximations for juvenile fishes is one way to understand how food consumption may affect fish growth. If variations in growth rate are strongly mirrored by past food status, then the condition (degree of well-being) of fish can be potentially used as a reference for relative prey availability. Furthermore, confirming that there is a positive relationship between food availability and fish growth rate is a critical first step to deepen our understanding of growth rate variation as well as examining if growth can be a proxy for habitat quality.

The California killifish (Fundulus …

Rodent Dental Microwear Texture Analysis As A Proxy For Fine-Scale Paleoenvironment Reconstruction, Jenny H. E. Burgman

Graduate Theses and Dissertations

Dental microwear texture analysis (DMTA) of fossil fauna has become a valuable tool for dietary inference and paleoenvironment reconstruction. Most of this work has utilized larger taxa with larger home ranges. These studies may result in broader-scale habitat inferences that could mask the details of complex mosaic habitats. Rodent DMTA offers an opportunity to work at finer spatial scales because most species have smaller home ranges. Rodents are also keystone species within their ecosystems, abundant, ubiquitous, and found in many fossil deposits. These attributes make them excellent proxies for environmental reconstructions. However, the application of DMTA to rodents remains relatively …

The Effects Of Dissolved And Suspended Solids On Freshwater Meiofauna, Jessica Cline

Honors Theses

Meiofauna include small-sized animals (< 1mm) distributed in all aquatic ecosystems on Earth, where they play fundamental trophic and ecological roles. The biodiversity of marine meiofauna and its links with anthropogenic activities is routinely investigated, however, freshwater communities are less known. This is particularly true for the Southeastern United States, which is greatly investigated and elected a hotspot of biodiversity for larger species but very little is known about the meiofauna. The purpose of this research is to reveal the biodiversity of meiofauna from the Tennessee River and test for potential correlations with anthropogenic activities. As a proxy for pollution, dissolved and suspended solids were considered in this study. The research hypothesis is that meiofaunal biodiversity would be affected by possible changes of dissolved and suspended solids in the water column. Possible mechanisms causing biodiversity shifts could be ascribed to osmotic stresses of animals to cope with variation in dissolved solids or, more indirectly, because different sunlight penetration caused by suspended solids would affect primary production. To test the hypothesis, water samples were collected from nine stations located along the Tennessee River in Hamilton County. Each station was visited three times, and, during each visit, environmental parameters (including dissolved and suspended solids) were measured. Meiofauna biodiversity (estimated as richness, community composition, and phylogenetic diversity) was revealed using a metagenomic approach. Statistical analyses were applied to test for possible correlations between the biodiversity estimates and the measured environmental parameters. Results show a high biodiversity of meiofauna with more than 200 amplicon-sequence variants distributed across 10 metazoan phyla. Environmental conditions are highly variable among stations and statistical analyses show that while both dissolved solids (TDS) and turbidity (suspended solids, NTU) did not significantly affect meiofauna biodiversity in the collected samples, various other water, and sediment metrics were found to be significant predictors of meiofauna biodiversity. In conclusion, the results of this project not only reveal for the first time the meiofauna biodiversity from the Tennessee River, but also suggest that meiofauna could be used as bioindicators for several anthropogenic activities in freshwater ecosystems.

The Relationship Between Substrate Composition, Community Structure And Feeding Preferences Of Parrot Fishes (Scaridae) In Anmardub, Guna Yala Coastal Reefs, Caitlin Amman

Independent Study Project (ISP) Collection

Coral reefs are important marine ecosystems, as they support biodiversity and generate buffer zones, yet their abundance is incredibly limited globally. One of the main threats that coral reefs face is excessive macroalgal coverage, which limits sunlight from reaching corals, and thus, limits the energy that can reach them. Parrot fish (Scaridae) are keystone herbivores, as they consume macroalgae growing on corals, which aids in reef survivability. While there is previous research on the abundances, sizes, and feeding habits of Scaridae species in the Caribbean, there is no published research on how community structure and feeding preferences of parrot fishes …

Connecticut Embayment Characteristics 2022, Jamie M.P. Vaudrey, James E. O'Donnell

Department of Marine Sciences

Data on Connecticut embayment characteristics. This Excel file is the centerpiece for capturing embayment characteristics as presented in RESPEC (2022), developed specifically for this project. Some parameters such as watershed size, embayment size, and tidal range were pulled from other sources described in Appendix A of RESPEC (2022), but much of the data and indicators in the Excel file were developed for this project. Each parameter included in the spreadsheet is fully defined in Appendix A of RESPEC (2022). All data available in the spreadsheet are provided by embayment in Appendix C of RESPEC (2022), including the results of bathymetric …

2022 Gray Wolf Questions And Answers, United States Fish And Wildlife Service

United States Fish and Wildlife Service: Publications

2022 Gray Wolf Questions and Answers

What does the February 10, 2022, ruling mean?

How does this ruling affect wolves in the Northern Rocky Mountains?

When does the court decision to vacate the delisting rule go into effect?

What is the legal status of gray wolves as of this ruling?

Is the Service continuing its status review of wolves in the western United States?

Is emergency listing an option for the Northern Rocky Mountain population?

Are wolf hunts going to stop as a result of the court decision?

How does this ruling affect wolves in Yellowstone National Park?

Where can …

Spatial And Temporal Variability Of Mercury In Upper And Lower Red Lake Walleye, Tyler Orgon

Biology Graduate Theses

Mercury is a global pollutant that is released into our environment by natural and anthropogenic processes resulting in extensive studies conducted on mercury cycling in aquatic ecosystems which has led to the issuance of human-health-based fish-consumption advisories. We examined total mercury concentrations in Walleye Sander vitreus from Upper and Lower Red Lakes, located in north central Minnesota, between 2019 and 2020. Upper and Lower Red Lake form a contiguous water body consisting of two large (483.1 and 665.6 km2, respectively) basins that are naturally connected by a 1.4 km-wide strait. Both basins are important fisheries for recreation, subsistence, and commercial …

Integrating Data Types To Estimate Spatial Patterns Of Avian Migration Across The Western Hemisphere, Timothy D. Meehan, Sarah P. Saunders, William V. Deluca, Nicole L. Michel, Joanna Grand, Jill L. Deppe, Miguel F. Jimenez, Erika J. Knight, Nathaniel E. Seavy, Melanie A. Smith, Lotem Taylor, Chad Witko, Michael E. Akresh, David R. Barber, Erin M. Bayne, James C. Beasley, Jerrold L. Belant, Richard O. Bierregaard, Keith L. Bildstein, Than J. Boves, John N. Brzorad, Steven P. Campbell, Antonio Celis-Murillo, Hilary A. Cooke, Robert Domenech, Laurie Goodrich, Elizabeth A. Gow, Aaron Haines, Michael T. Hallworth, Jason M. Hill, Amanda E. Holland, Scott Jennings, Roland Kays, Tommy King, Stuart A. Mackenzie, Peter P. Marra, Rebecca A. Mccabe, Kent P. Mcfarland, Michael J. Mcgrady, Ron Melcer, D. Ryan Norris, Russell E. Norvell, Olin E. Rhodes, Christopher C. Rimmer, Amy L. Scarpignato, Adam Shreading, Jesse L. Watson, Chad R. Wilsey

United States Department of Agriculture Wildlife Services: Staff Publications

For many avian species, spatial migration patterns remain largely undescribed, especially across hemispheric extents. Recent advancements in tracking technologies and high-resolution species distribution models (i.e., eBird Status and Trends products) provide new insights into migratory bird movements and offer a promising opportunity for integrating independent data sources to describe avian migration. Here, we present a three-stage modeling framework for estimating spatial patterns of avian migration. First, we integrate tracking and band re-encounter data to quantify migratory connectivity, defined as the relative proportions of individuals migrating between breeding and nonbreeding regions. Next, we use estimated connectivity proportions along with eBird occurrence …

Low-Head Dam Removal Increases Functional Diversity Of Stream Fish Assemblages, Adam Christopher Jones

Masters Theses

Despite the growing number of dam removals to date, very few have been studied to understand their impacts on stream fish communities. Despite being the most common type of dam in the U.S., an even smaller proportion of studies focus on the impacts of low-head dam removals, instead, focusing on the impacts of removal of larger dams. In this study, two previously impounded Illinois rivers were monitored to assess the impacts of low-head dam removal on the functional assemblage of stream fishes. This was accomplished by aggregating fishes into habitat and reproductive guilds, relating community changes to habitat, environmental metrics, …

Informing Wetland Management With Waterfowl Movement And Sanctuary Use Responses To Human-Induced Disturbance, Fiona Mcduie, Austen A. Lorenz, Robert C. Klinger, Cory T. Overton, Cliff L. Feldheim, Joshua T. Ackerman, Michael L. Casazza

Faculty Research, Scholarly, and Creative Activity

Long-term environmental management to prevent waterfowl population declines is informed by ecology, movement behavior and habitat use patterns. Extrinsic factors, such as human-induced disturbance, can cause behavioral changes which may influence movement and resource needs, driving variation that affects management efficacy. To better understand the relationship between human-based disturbance and animal movement and habitat use, and their potential effects on management, we GPS tracked 15 dabbling ducks in California over ~4-weeks before, during and after the start of a recreational hunting season in October/November 2018. We recorded locations at 2-min intervals across three separate 24-h tracking phases: Phase 1) two …

Characterization Of Cdom In The Elkhorn Slough Estuary Using Eem Spectroscopy And Its Potential For Macrophyte Monitoring, María Vila Duplá

Faculty Research, Scholarly, and Creative Activity

The Elkhorn Slough estuary is an upwelling-influenced system located in Monterey Bay, California. It is of great ecological importance, as it provides essential habitat to over 750 species, and is one of the largest estuaries in California. The sources and distribution of chromophoric dissolved organic matter (cDOM) in Elkhorn Slough are strongly influenced by geochemical processes linked to the transition between sea and continent, and to anthropogenic activity from adjacent lands. In 2016, water samples were collected from across the Elkhorn Slough estuary to assess the sources and spatial dynamics of cDOM and its components throughout the system. Using EEM …

A Phenological Analysis Of Páramo Vegetation Along An Altitudinal Gradient: The Influence Of Camelids On Andean Flora In The Páramo Of Chimborazo, Ecuador, Tessa Seifried

Independent Study Project (ISP) Collection

This study hopes to reveal the mechanisms behind camelid-plant interactions in the Chimborazo province of Ecuador, which is known for having a large population of domesticated alpacas (Vicugna pacos), along with wild vicuñas (Vicugna vicugna) that were reintroduced into the area 30 years ago. These camelid species, especially vicuñas, are understudied within Ecuador in regards to their effects on plant composition, diversity, and spatial phenology. To gain a better insight into this topic, three sites were chosen: a site inhabited by only vicuña, a site inhabited by only alpaca, and a site inhabited by both species. The vicuña site sat …

A Ladder Of Endemicity: A Pioneering Study Of Anuran Communities Along An Elevational Gradient In The Eastern Andean Cloud Forests, Ecuador, Ella Halbert

Independent Study Project (ISP) Collection

Per unit of area, Ecuador is home to the most herpetofauna of any region on Earth, yet many ecosystems are under researched. Positioned between the Eastern Andes and the Amazon rainforest, the Río Pastaza Basin of Ecuador has been the recent focus of anuran biodiversity surveys and is home to many endemic species. This study aimed to determine how the anuran community composition of a vertical transect in the Llanganates National Park varied between elevations. A 7-day expedition was conducted along a new trail up Abitagua Range spanning 1,050 m in elevation. Each night, visual encounter surveys were employed to …

Rabbit Control: Rhdv1 K5, Department Of Primary Industries And Regional Development, Western Australia

Biosecurity factsheets

The national release of the Korean strain of rabbit haemorrhagic disease virus, RHDV1 K5, took place during the first week of March 2017. It was the first time in 20 years a new rabbit biocontrol agent had been released into Australia, and was part of a 20-year national biocontrol plan for rabbits. More than 600 release sites were selected, including 110 sites in Western Australia (WA).

RHDV1 K5 is a naturally occurring Korean variant of the rabbit haemorrhagic disease virus (RHDV). Its release was expected to boost management and help slow the increase in rabbit numbers. RHDV1 K5 does not …

The Potential Influence Of Abiotic Conditions On Mussel Species Abundance In San Francisco Bay, Alexandra G. Farrell, M. Christina Vasquez Dr.

Honors Thesis

Climate change has negatively altered seawater conditions, which may have severe implications for marine ecosystems. Mussels are susceptible to environmental changes since they are primary consumers and filter-feeding bivalves. Two species of particular interest to the West Coast of the U.S. are Mytilus galloprovincialis and M. trossulus. M. trossulus is native to the California Coast and was historically prevalent from Southern California to Washington. However, with increased shipping and rising seawater temperature, M. galloprovincialis, an invasive species from the Mediterranean, pushed the species range of M. trossulus poleward. M. trossulus is more tolerant of cold seawater with variable salinity while …

The Effect Of Changing Substrate On Arctic Aquatic Invertebrates Abundance, Tom Dolman

Michael D. Wilson Symposium

Climate change is directly affecting tundra ecosystems in northern regions, and warming temperatures have caused discontinuous permafrost and thawing sediments across the region. This project investigates how increasing erosion and the foraging patterns of migratory snow geese may degrade habitat for aquatic invertebrates in the upper Mast River, located in Wapusk National Park, Manitoba, Canada. In the past two decades, many of the important species of aquatic invertebrates have shown declines. Declining invertebrate populations are predicted to affect aquatic ecosystems and decrease the resources available to shorebirds and waterfowl, which breed and migrate through this area.

Assessing And Mapping The Spatial-Temporal Change In Forest Phenology Of Arabuko-Sokoke Forest Using Moderate Resolution Satellite, Bailey Ytterdahl

Independent Study Project (ISP) Collection

This study focuses on coastal forests in Kenya that have some of the highest variety of flora and fauna, specifically Arabuko Sokoke Forest. Arabuko Sokoke Forest is located 110 miles north of Mombasa and 18 kilometers south of Malindi. This forest is known to be a worldwide biodiversity hotspot that is home to endemic and rare plants and animals. Within the Arabuko Sokoke Forest ecosystem, there are two main issues that challenge the conservation of the area. First, there has been more competition for land, primarily for agriculture and development. Second, there is an increase demand for forest resources due …

An Assessment Of Terrestrial Decapoda Diversity Across Three Ecological Zones In Mida Creek, Kenya, Reese Yount

Independent Study Project (ISP) Collection

Mangroves make up one of the most effective natural remedies at combating climate change today. They represent great commercial interest worldwide and yet, are being degraded at an unsustainable rate. If successful mangrove conservation plans are to be implemented for our posterity, mangrove ecosystems need to be better understood at the community level. Mangrove crabs make up the most diverse and populace mangrove inhabitants. They are classified as ecosystem engineers and their potential for being used as bioindicators makes them integral to assessing mangrove health. Yet, their diversity and distribution patterns are not well understood. The aim of this study …

Non-Breeding Ecology Of Loggerhead Shrikes In An Intensive Agricultural Region, Emily Rose Donahue

Student Theses and Dissertations

As intensive agriculture has transformed much of the landscape across central North America, many grassland species have had to learn to adjust these new, highly homogeneous habitats while facing steep population declines. The Loggerhead Shrike (Lanius ludovicianus; hereinafter shrike) is one such declining species that persists in these agricultural landscapes. However, we lack information on the sustainability of these populations, and shrike non-breeding ecology, as for most passerines, remains understudied. Specifically, little is known about non-breeding behavior, diet, survival, site fidelity, and habitat selection. If survival, space use, and habitat selection metrics differ between demographic groups within non-breeding populations also …

Plant Community Response To The Combined Effects Of Elevation, And Simulated Nutrient And Sediment Loading In Sagittaria Lancifolia-Dominated Wetlands, Donnie Day

LSU Master's Theses

Coastal wetlands are experiencing threats to their long-term sustainability brought about by the combined effects of relative sea-level rise and human modifications to hydrology, sediment delivery and nutrient loading. Restoration and management strategies can include adding sediment to the surface of deteriorating marshes to facilitate positive feedbacks among elevation, plant productivity, sediment trapping, and accretion; however, if delivered using nitrate-enriched river waters, belowground biomass and soil organic matter pools may be negatively affected, resulting in the acceleration of wetland loss. Overall, there is limited information on the combined effects of nutrient loading, sedimentation, and flooding dynamics in regulating feedbacks among …

Solutions Human Centered Approach To Conservation, Illustration Department, History, Philosophy, + The Social Sciences Department

Illustration Course Work & Materials

"These essays were were written and illustrated by students at the Rhode Island school of Design in February, 2021. Their perspectives are entirely personal and reflect their efforts within a 5.5-week fused studio/seminar course that was centered on the Sixth Mass Extinction and how biodiversity is changing because of humans. Discovering that science communication is more than delivering just the facts, students were invited to research a topic of personal interest that is relevant to human impacts on biodiversity. Through analysis of data and other scientific information, each sought to synthesize their research and opinions on their topic through a …

Infaunal Bivalve Density And Richness In North Inlet Estuary, South Carolina: Seasonal Patterns And Ecological Factors, Valerie M. Knowles, Juliana Harding

Honors Theses

Estuarine bivalves recruit to benthic habitats after the larvae are in the planktonic stage. The observed infaunal bivalve density relates to larval supply from adult reproduction during warmer months as well as larval and juvenile mortality post-recruitment. The purpose of this research was to examine annual and seasonal patterns of infaunal bivalve density and richness in the context of habitat water temperature and salinity. Cores were collected biweekly from Bly Creek in North Inlet estuary between January 2019 and February 2020. Temperatures ranged from 9-30 ºC and salinity ranged from ~17-36 psu. Bivalves were sieved out of the cores, counted, …

The Effects Of Multiple Stressors On Stream Communities: The Convergence Of Drought, Nutrient Pollution, And Invasive Species, Robert Joseph Fournier Iii

Graduate Theses and Dissertations

Freshwater systems experience multi-faceted degradation from a variety of ecological and environmental stressors. Three common stressors in these systems, drought, nutrient pollution, and invasive species, have wide-ranging effects on stream population- community- and ecosystem dynamics. We have a broad understanding of how each of these stressors works to influence stream systems independently. However, we still know relatively little about if, and how, these stressors might interact when they co-occur. Though drought is a natural part of many stream systems, all three of these stressors can be exacerbated or facilitated by anthropogenic actions. Accordingly, as human population and resource use continue …

Multidecadal Analysis Of Beach Loss At The Major Offshore Sea Turtle Nesting Islands In The Northern Arabian Gulf, Rommel H. Maneja, Jeffrey D. Miller, Wenzhao Li, Rejoice Thomas, Hesham El-Askary, Sachi Perera, Ace Vincent B. Flandez, Abdullajid U. Basali, Joselito Francis A. Alcaria, Jinoy Gopalan, Surya Prakash Tiwari, Mubarak Al-Jedani, Perdana K. Prihartato, Ronald A. Loughlan, Ali Qasem, Mohamed A. Qurban, Wail Falath, Daniele Struppa

Mathematics, Physics, and Computer Science Faculty Articles and Research

Undocumented historical losses of sea turtle nesting beaches worldwide could overestimate the successes of conservation measures and misrepresent the actual status of the sea turtle population. In addition, the suitability of many sea turtle nesting sites continues to decline even without in-depth scientific studies of the extent of losses and impacts to the population. In this study, multidecadal changes in the outlines and area of Jana and Karan islands, major sea turtle nesting sites in the Arabian Gulf, were compared using available Kodak aerographic images, USGS EROS Declassified satellite imagery, and ESRI satellite images. A decrease of 5.1% and 1.7% …

Swimming Point Benthic Community Condition Elizabeth River (2019), Daniel M. Dauer

Elizabeth River Reports

Executive Summary

The subtidal macrobenthic communities off Swimming Point in the Elizabeth River were quantitatively sampled in summer 2019. The primary objective of this study was to characterize the ecological condition of the benthos compared to benthic data collected in summer 2010 (Dauer 2011).

The estimated the level of degraded benthic bottom of the Swimming Point stratum (BIBI < 3.0) in 2019 was 64% ± 18.8% a decrease from the 2010 value of 84% ± 14.0%. The level of severely degraded bottom (BIBI ≤ 2.0) in 2019 was 28% ± 17.6% compared to the 2010 value of 52% ± 19.6%. The ecological condition of benthic communities at Swimming Point in 2019 were comparable to the values for the Mainstem segment of the Elizabeth River in 2019 which had an estimated degraded benthic bottom of 52% ± 19.6% and a value of 36% ± 18.8 of severely degraded bottom.

The BIBI and its metrics showed a mixture of improvements and degradations in benthic community condition. Compared to the previous benthic community condition reported in Dauer (2011) the 2019 Swimming Point benthos: (1) the average BIBI value improved significantly from 2.2 ± …

Water Quality Assessment In The Occurrence Of Acanthaster Spp. (Crown-Of-Thorns Starfish, Cots) On Coral Reefs In Menjangan Island, Bali, Indonesia, Novia Arinda Pradisty, Eghbert Elvan Ampou, Rizki Hanintyo

Makara Journal of Science

Aquatic stressors are known to cause biological impairment that can result in biodiversity loss in several Marine Protected Areas (MPA), including in Menjangan Island, West Bali National Park. The objectives of this study were to correlate the changes in water quality parameters with the biological effect of Crown-of-Thorns starfish (CoTS) population dynamics and to assess the most applicable parameters for continuous environmental monitoring. Field observations and surveys were conducted three times in 2017, during the wet season, dry season and season transition, in order to assess the effect of seasonal variability. Redundancy Analysis (RDA) was performed to determine the relationship …

Foliar Application Of Low Concentrations Of Titanium Dioxide And Zinc Oxide Nanoparticles To The Common Sunflower Under Field Conditions, Marek Kolenčík, Dávid Ernst, Martin Urík, Ľuba Ďurišová, Marek Bujdoš, Martin Šebesta, Edmund Dobročka, Samuel Kšiňan, Ramakanth Illa, Qian Yu, Huan Feng, Ivan Černý, Veronika Holišová, Gabriela Kratošová

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Nano-fertilisers have only recently been introduced to intensify plant production, and there still remains inadequate scientific knowledge on their plant-related effects. This paper therefore compares the effects of two nano-fertilisers on common sunflower production under field conditions. The benefits arising from the foliar application of micronutrient-based zinc oxide fertiliser were compared with those from the titanium dioxide plant-growth enhancer. Both the zinc oxide (ZnO) and titanium dioxide (TiO₂) were delivered by foliar application in nano-size at a concentration of 2.6 mg·L⁻¹. The foliar-applied nanoparticles (NPs) had good crystallinity and a mean size distribution under 30 nm. …

Benthic Biological Monitoring Of The Elizabeth River Watershed (1999 And 2019), Daniel M. Dauer

Elizabeth River Reports

Executive Summary

A study of the macrobenthic communities of the Elizabeth River watershed was conducted in summer 1999 and again in summer 2019 – a 20-year span. The primary objective of the Benthic Biological Monitoring Program of the Elizabeth River watershed was to characterize the ecological condition of regional areas of the tidal waters of the Elizabeth River watershed as indicated by the structure of the benthic communities. These characterizations are based upon application of the Benthic Index of Biotic Integrity (BIBI) developed for the Chesapeake Bay to five primary strata - the Mainstem of the river, the Lafayette River, …