Great Lakes Shoreline Research Articles

Microbe-sediment interactions in Great Lakes recreational waters: Implications for human health risk.

Microbial assessments of recreational water have traditionally focused on culturing or DNA-based approaches of the planktonic water column, omitting influence from microbe-sediment relationships. Sediment (bed and suspended) has been shown to often harbour levels of bacteria higher than the planktonic phase. The fate of suspended sediment (SS) bacteria is extensively related to transport dynamics (e.g., deposition) of the associated sediment/floc. When hydraulic energy allows, SS will settle, introducing new (potentially pathogenic) organisms to the bed. With turbulence, including waves, currents and swimmers, the risk of human ingestion is elevated due to resuspension of bed sediment and associated microbes. This research used multiplex nanofluidic reverse transcriptase quantitative PCR on RNA of bacteria associated with bed and SS to explore the active bacteria in freshwater shorelines. Bacterial genes of human health concern regarding recreational water use were targeted, such as faecal indicator bacteria (FIB), microbial source tracking genes and virulence factors from waterborne pathogens. Results indicate avian sources (i.e., gulls, geese) to be the largest nonpoint source of FIB associated with sediment in Great Lakes shorelines. This research introduces a novel approach to microbial water quality assessments and enhances our understanding of microbe-sediment dynamics and the quality of freshwater beaches.

Great Lakes Shoreline Restoration: Evaluation and Benchmarks

Great Lakes Shoreline Restoration: Evaluation and Benchmarks

Coalescent methods reconstruct contributions of natural colonization and stocking to origins of Michigan inland Cisco (Coregonus artedi)

Fish population structure in previously glaciated regions is often influenced by natural colonization processes and human-mediated dispersal, including fish stocking. Endemic populations are of conservation interest because they may contain rare and unique genetic variation. While coregonines are native to certain Michigan inland lakes, some were stocked with fish from Great Lakes sources, calling into question the origin of extant populations. While most stocking targeted lake whitefish (Coregonus clupeaformis), cisco (C. artedi) were also stocked from the Great Lakes to inland waterbodies. We used population genetic data (microsatellite genotypes and mitochondrial (mt)DNA sequences), coalescent modeling, and approximate Bayesian computation to investigate the origins of 12 inland Michigan cisco populations. The spatial distribution of mtDNA haplotypes suggests Michigan is an introgression zone for two ancestral cisco lineages associated with separate glacial refugia. Low levels of genetic diversity and high levels of genetic divergence were observed for populations located well inland of the Great Lakes relative to populations occupying waterbodies near the Great Lakes. Estimates of recent Great Lakes gene flow ranged from 27 to 48% for populations near the Great Lakes shoreline but were substantially lower (under 8%) for populations further inland. Inland lakes with elevated recent gene flow estimates may have been recipients of stocked coregonine fry, including cisco. Low levels of genetic diversity paired with a high likelihood of endemism as indicated by strong genetic divergence and low Great Lakes population inputs suggest the analyzed cisco populations occupying southern Michigan kettle lakes are of elevated conservation interest.

Patterns and processes of beach and foredune geomorphic change along a Great Lakes shoreline: Insights from a year-long drone mapping study along Lake Michigan

Coastal storms are an important driver of geomorphic change along Great Lakes shorelines. While there is abundant anecdotal evidence for storm impacts in the region, only a handful of studies over the last few decades have quantified them and addressed system morphodynamics. Annual to seasonal lake-level fluctuations and declining winter-ice covers also influence coastal response to storms, yet relationships between hydrodynamics and geomorphology are poorly constrained. Given this, the Great Lakes region lags behind marine coasts in terms of predictive modeling of future coastal change, which is a necessary tool for proactive coastal management. To help close this gap, we conducted a year-long study at a sandy beach-dune system along the western shore of Lake Michigan, evaluating storm impacts under conditions of extremely high water level and absent shorefast ice. Drone-derived beach and dune topography data were used to link geomorphic changes to specific environmental conditions. High water levels throughout the year of study facilitated erosion during relatively minor wave events, enhancing the vulnerability of the system to a large storm in January 2020. This event occurred with no shorefast ice present and anomalously high winter water levels, resulting in widespread erosion and overwash. This resulted in 20% of the total accretion and 66% of the erosion documented at the site over the entire year. Our study highlights the importance of both antecedent and present conditions in determining Great Lakes shoreline vulnerability to storm impacts.

A hierarchical Bayesian model of storm surge and total water levels across the Great Lakes shoreline – Lake Ontario

This study presents a novel approach to determine the distribution of compound flood events composed of storm surge and static water levels along the Great Lakes shoreline. A mixture distribution of the bulk (Student-t) and tail (GPD-negative binomial) components of storm surge is estimated in a hierarchical Bayesian modeling framework. Parameters are modeled across the entire shoreline using Gaussian processes and hourly gauged data, with priors for spatial autocorrelation informed by numerical output from a lake hydrodynamic model. The distribution of total water levels is obtained through Monte Carlo sampling that combines the estimated distribution of surge with stochastic traces of static lake levels that account for water level management, seasonality, and plausible variability in water supplies. The approach can therefore support coastal flood risk assessments in cases when the distribution of static water levels changes are due to altered water level management or climate change. The model is applied in a case study on Lake Ontario. Results suggest that spatial variability in parameter estimates varies significantly by month and mixture distribution component. Evaluations of performance indicate the model is able to capture adequately storm surge behavior at gauges across the lakeshore, even under cross-validation. A frequency analysis of total water levels at two ungauged sites is presented, with specific attention given to the implications of model assumptions on uncertainty in design events. The paper concludes with a discussion of model limitations and avenues for future work.

Evaluating the impacts of foreshore sand and birds on microbiological contamination at a freshwater beach

Beaches along the Great Lakes shorelines are important recreational and economic resources. However, contamination at the beaches can threaten their usage during the swimming season, potentially resulting in beach closures and/or advisories. Thus, understanding the dynamics that control nearshore water quality is integral to effective beach management. There have been significant improvements in this effort, including incorporating modeling (empirical, mechanistic) in recent years. Mechanistic modeling frameworks can contribute to this understanding of dynamics by determining sources and interactions that substantially impact fecal indicator bacteria concentrations, an index routinely used in water quality monitoring programs. To simulate E. coli concentrations at Jeorse Park beaches in southwest Lake Michigan, a coupled hydrodynamic and wave–current interaction model was developed that progressively added contaminant sources from river inputs, avian presence, bacteria–sediment interactions, and bacteria–sand–sediment interactions. Results indicated that riverine inputs affected E. coli concentrations at Jeorse Park beaches only marginally, while avian, shoreline sand, and sediment sources were much more substantial drivers of E. coli contamination at the beach. By including avian and riverine inputs, as well as bacteria–sand–sediment interactions at the beach, models can reasonably capture the variability in observed E. coli concentrations in nearshore water and bed sediments at Jeorse Park beaches. Consequently, it will be crucial to consider avian contamination sources and water-sand-sediment interactions in effective management of the beach for public health and as a recreational resource and to extend these findings to similar beaches affected by shoreline embayment.

A Complicated Groundwater Flow System Supporting Ridge-and-Swale Wetlands in a Lake Michigan Strandplain

Beach ridges and wetland swales formed in embayments along Great Lakes shorelines during Holocene lake-level changes. Vegetation differences among swales suggested influence from differing groundwater flow systems. We characterized the hydrology across 79 ridge/swale wetlands in the Manistique/Thompson embayments of Lake Michigan using chemical and physical methods. Cross-sections were built from geologic data, and nested piezometers were installed across three ridges/swales where upwelling was noted. Stainless steel piezometers driven in 30 swales were sampled and water analyzed for specific conductance, alkalinity, and major ions. Surface water from 11 swales was analyzed. Water dominated by Ca-Mg-HCO3 was prevalent across the strandplain, with specific conductance generally less than 100 μS/cm. Conductivity, Ca, Mg, and HCO3 in groundwater were greater at identified groundwater discharges; where an amalgamated beach ridge forms a surficial groundwater divide; and swales nearer Lake Michigan that likely receive greatly mineralized water from a deeper aquifer. Repositioning of the shoreline as the embayments filled over the past 4700 years, coupled with isostatic rebound and changes in lake water levels, altered head differentials and changed the sources of discharge from local, intermediate, and deep flow systems over time. Extant plant communities are consistent with the groundwater dependence of these wetlands.

St. Lawrence Seaway: Western Great Lakes Basin

The St. Lawrence Seaway connects Lake Superior, Lake Huron, Lake Michigan, Lake Erie and Lake Ontario to the Atlantic Ocean. The lakes and connecting rivers, St. Mary’s, St. Claire, Detroit, Niagara and St. Lawrence, have been a major artery for transportation, migration and trade. The Menominee River flows into Green Bay and Lake Michigan and connects to the St. Lawrence Seaway. The Great Lakes have been sailed for trading and commercial purposes since at least the 17th century. Approximately 6000 ships have sunk killing more than 30,000 sailors and passengers. Cold Canadian winds over the three Western Great Lakes pick up moisture when the lakes are not yet frozen and create snow belts in the states of Wisconsin, Michigan and in Ontario, Canada. The Western Great Lakes moderate the seasonal temperatures as they absorb heat and cool the air in the summer. The lakes radiate heat in the fall. This temperature buffering creates fruit belts further north of where the fruit is traditionally grown. During the 1950s and 1960s all of the Agent Blue, the arsenic containing herbicide used in Vietnam War, was manufactured on the banks of the Menominee River by the Ansul Company at Marinette, Wisconsin. The groundwater and the river bottom are now heavily contaminated with arsenic compounds that were released from 1957 to 1977 by Ansul as a result of the manufacture of the herbicide. The linkage of Lake Michigan to the Mississippi River has allowed Chicago’s wastewater to be disposed of into the tributaries of the Illinois River and Mississippi River to avoid contaminating Lake Michigan the source of Chicago’s drinking water. An unintended consequence of linking the Western Great Lakes basin with the Mississippi River basin was the creation of the wet pathway (Chicago Sanitary and Ship Canal) through which the flying Asian carp is trying to use to get into the Great Lakes. An electric fish barrier was constructed on the Chicago Sanitary and Ship Canal in an attempt to prevent the carp from migrating into Lake Michigan, the Great Lakes basin and the St. Lawrence Seaway. The Western Great Lakes shorelines are actively eroding partly as a consequence of the high surface water levels. In June of 2020 Lake Michigan, Lake St. Claire and Lake Huron experienced the highest water level ever recorded since the 1800s. The high risk erosion areas are retreating at the average rate of 30 cm per year for the last 15 years. Planned urban development in a high risk area helps to prevent the loss of buildings. Locating structures back from lake bluffs promotes natural shorelines and reduces the need for engineered shore protection. Erosion of the sediment under the Mackinac Bridge and pipeline has occurred. The pipeline which carries 87 million liters of oil per day between Sarnia, Ontario and Superior, Wisconsin is at risk.

Applying best-worst scaling to rank ecosystem and economic benefits of restoration and conservation in the Great Lakes

Since 2010, over $2.4 billion in public funds have been invested in the cleanup and restoration of the Great Lakes Basin through the Great Lakes Restoration Initiative. Efforts have targeted restoration of Areas of Concern and other degraded sites. While the ecological benefits of Great Lakes restoration have been highlighted by the Environmental Protection Agency, and the economic benefits studied by the binational International Joint Commission, public preferences for Great Lakes conservation and restoration have not been well studied. Using best-worst scaling and a seven-preference choice set, 1,215 Basin residents quantitatively ranked their preferred reasons to restore and conserve Great Lakes shorelines and waterways, with a focus on restoration at Areas of Concern and National Park Service sites. The analysis shows the most preferred reason for restoration and conservation is to promote human health, followed by the protection of native species, and the prevention of new invasive species from entering the Great Lakes. The least preferred reason for restoration and conservation is to improve local property values. Although respondents' top reason was human-centered, respondents' preferred ecosystem conservation over the benefits of economic revitalization, recreational use, and improved property values. Preferences analyzed by gender, income, and home location followed these same rankings. Preferences for habitat restoration and the prevention of invasive species align with the focus areas guiding the Great Lakes Restoration Initiative, providing evidence of public support for this expansive, publicly funded restoration effort.

An endemic plant and the plant-insect visitor network of a dune ecosystem

Network theory increasingly is used to quantify and evaluate mutualistic interactions, such as those among plants and their flower-visiting insects or pollinators. Some plant species have been shown to be important in community structure using network metrics; however, the roles of plant taxa, particularly rare species, are not well understood. Pitcher's thistle (Cirsium pitcheri), a threatened endemic of Great Lakes shorelines, flowers late-June to early-August, when other floral resources may be less abundant or unavailable. We performed 10 min insect visitor observations on all insect pollinated plants in 44–10 m by 10 m plots at Sturgeon Bay, northern lower MI, USA, during C. pitcheri flowering and recorded plant species, number of open flowers, species of insect visiting, and number of visits by insects. Pitcher's thistle received 18.2% of all 600 recorded visits, 61.1% more than the next most visited plant. Pitcher's thistle also received visits from 22 of the 59 different insect species in the network, twice as many as the next most visited plant species. Species-level network analysis metrics showed that Pitcher's thistle was most generalized, with greatest species strength, betweenness, and connectance scores of any other plant taxon, demonstrating network topological importance. Pitcher's thistle received significantly more insect visits relative to its abundance that did any other plant species. Therefore, conservation of C. pitcheri and of other rare taxa, particularly in xeric and low diversity systems, can be significant beyond species-level management and may extend to conservation of the plant-insect community.

DEVELOPMENT AND VALIDATION OF A STORM SURGE AND WAVE MODEL FOR LAKE HURON (GREAT LAKES, USA)

The Federal Emergency Management Agency (FEMA) is tasked with developing flood insurance rate maps along coastlines and major water bodies within the United States, which includes the U.S. portion of the Great Lakes shoreline. Previous flood studies have developed storm surge and wave models of the Great Lakes (including Lake Huron) in support of FEMA’s efforts; however, an independent technical review of those previous coastal flood studies in Lake Huron revealed technical deficiencies in the methods and tools used to generate the wave conditions needed to support overland mapping. Most paramount of these was the fact that starting wave conditions for one dimensional (1D) transformation from a two-dimensional (2D) model were taken from deep water. Using 1D methods to shoal and refract waves to the coastline for runup and/or overland wave analysis may fail to capture the more complex nature of wave refraction/diffraction that 2D wave models can capture. Further, this method omits the development of the directional wave spectra in the nearshore region. To address this concern, a coupled 2D wave and water level model (ADCIRC+SWAN) was developed to hindcast historical storms that have occurred in Lake Huron. These model results will be used to drive the 1D methods to assess nearshore wave hazards from locations near the surfzone limit.

Radar quantifies migrant concentration and Dawn reorientation at a Great Lakes shoreline

BackgroundMillions of flying migrants encounter the Great Lakes and other large water bodies on long-distance flights each spring and fall, but quantitative data regarding how they traverse these obstacles are limited. Shorelines are known areas of migrant concentration due to the ecological barrier effect, but details on the magnitude of this concentration and the flight behaviors causing it are largely unknown and difficult to quantify. Mobile avian radar can provide a unique view of how birds and bats move across landscapes by tracking thousands of individual migrants moving through a sample volume that extends multiple kilometers in radius.ResultsDuring the spring of 2014 we used two avian radar units to compare migration patterns at shoreline (1.5 km from the shore) and inland (20 km from the shore) sites along the eastern shoreline of Lake Michigan in the north-central US. We found shoreline activity to be 27% greater than inland activity over all time periods, and 132% greater during the hour surrounding dawn. An analysis of flight directions found that migrants flew to the north and northwest during dusk and night, with many heading out over the lake, but shifted direction towards the east at dawn, as those flying over water reoriented towards land. This shift in direction, which was most intense at the shoreline, may contribute to the higher concentrations of migrants observed at shorelines in this study and others.ConclusionsThese findings help confirm and quantify the phenomenon of nocturnal migrant reorientation at dawn, and also stress the functional importance of coastal regions for aerial migrants. The high use of coasts by migrants highlights the importance of conserving shoreline stopover habitat, which often competes with anthropogenic uses. We suggest using a high degree of caution when assessing potential impacts from development in these sensitive environments, and encourage protection of these high-use areas.

Virulence and biodegradation potential of dynamic microbial communities associated with decaying Cladophora in Great Lakes

Cladophora mats that accumulate and decompose along shorelines of the Great Lakes create potential threats to the health of humans and wildlife. The decaying algae create a low oxygen and redox potential environment favoring growth and persistence of anaerobic microbial populations, including Clostridium botulinum, the causal agent of botulism in humans, birds, and other wildlife. In addition to the diverse population of microbes, a dynamic chemical environment is generated, which involves production of numerous organic and inorganic substances, many of which are believed to be toxic to the sand and aquatic biotic communities. In this study, we used 16S-rDNA-based-amplicon sequencing and microfluidic-based quantitative PCR approaches to characterize the bacterial community structure and the abundances of human pathogens associated with Cladophora at different stages (up to 90days) of algal decay in laboratory microcosms. Oxygen levels were largely depleted after a few hours of incubation. As Cladophora decayed, the algal microbial biodiversity decreased within 24h, and the mat transitioned from an aerobic to anaerobic environment. There were increasing abundances of enteric and pathogenic bacteria during decomposition of Cladophora, including Acinetobacter, Enterobacter, Kluyvera, Cedecea, and others. In contrast, there were no or very few sequences (<0.07%) assigned to such groups in fresh Cladophora samples. Principal coordinate analysis indicated that the bacterial community structure was dynamic and changed significantly with decay time. Knowledge of microbial communities and chemical composition of decaying algal mats is critical to our further understanding of the role that Cladophora plays in a beach ecosystem's structure and function, including the algal role in trophic interactions. Based on these findings, public and environmental health concerns should be considered when decaying Cladophora mats accumulate Great Lakes shorelines.

Spatial Distribution and Air-Water Exchange of Organic Flame Retardants in the Lower Great Lakes.

Organic flame retardants (OFRs) such as polybrominated diphenyl ethers (PBDEs) and novel halogenated flame retardants (NHFRs) are ubiquitous, persistent, and bioaccumulative contaminants that have been used in consumer goods to slow combustion. In this study, polyethylene passive samplers (PEs) were deployed throughout the lower Great Lakes (Lake Erie and Lake Ontario) to measure OFRs in air and water, calculate air-water exchange fluxes, and investigate spatial trends. Dissolved Σ12BDE was greatest in Lake Ontario near Toronto (18 pg/L), whereas gaseous Σ12BDE was greatest on the southern shoreline of Lake Erie (11 pg/m(3)). NHFRs were generally below detection limits. Air-water exchange was dominated by absorption of BDEs 47 and 99, ranging from -964 pg/m(2)/day to -30 pg/m(2)/day. Σ12BDE in air and water was significantly correlated with surrounding population density, suggesting that phased-out PBDEs continued to be emitted from population centers along the Great Lakes shoreline in 2012. Correlation with dissolved Σ12BDE was strongest when considering population within 25 km while correlation with gaseous Σ12BDE was strongest when using population within 3 km to the south of each site. Bayesian kriging was used to predict dissolved Σ12BDE over the lakes, illustrating the utility of relatively highly spatially resolved measurements in identifying potential hot spots for future study.

Pre-settlement Snail Fauna on the Sandbanks Baymouth Bar, Lake Ontario, Compared with Nearby Contemporary Faunas

The terrestrial snail fauna in a pre-settlement soil layer, radiocarbon dated at approximately 1065–1560 years old, on the baymouth bar at Sandbanks Provincial Park, Lake Ontario, was compared with 4 nearby contemporary snail faunas from forested dunes.The pre-settlement sample differed in snail diversity, with 23 species compared with 9–20 species in contemporary samples. Six species were unique to the pre-settlement sample: Carychium exile, Euconulus fulvus, Gastrocopta armifera, Gastrocopta corticaria, Vallonia parvula, and Vertigo sp. The number of individual snails was much greater at the pre-settlement site when corrected for difference in size of sample area. The reason for the higher diversity, greater number of individuals, and different fauna associated with the pre-settlement area is unclear, but may be attributed to reduction and changes in the litter layer at the contemporary comparison sites caused by European earthworms. This work suggests that major erosional and depositional events occurred on Great Lakes shoreline dunes in the past and that these can be used to study post glacial mollusc faunas and past ecological processes, with some potentially significant results.

Population viability analysis and the effects of light availability and litter on populations of Cirsium pitcheri, a rare, monocarpic perennial of Great Lakes shorelines

An understanding of plant population dynamics in response to natural and anthropogenic influences is critical for rare species management. We present a long-term study and population viability analysis of a federally threatened monocarpic, Cirsium pitcheri, endemic to the Great Lakes, in northern Michigan. Population growth rates of C. pitcheri were highly variable; only four of the 14year-pairs studied during the 19yr study period indicated a growing population (λ>1). Elasticity analysis showed population growth was sensitive to seedling recruitment. We manipulated light and litter levels in the growth chamber to simulate natural succession or invasive plants and to determine their effects on seedlings and ultimately, population performance. The absence of shading and litter increased seedling emergence from 8% to 42%, but no simulated population had less than a 5% risk of extinction over a 25-year period. These populations are, strictly speaking, non-viable. Population viability and conservation of this species are linked to recruitment, including seedling success. Control of plant and animal invasive species and addition of greenhouse transplants to increase recruitment may help reverse population declines.

Blueprint for the Great Lakes Trail

The Great Lakes are vast yet vulnerable. There is a need to focus the public’s attention on the significance of the lakes for the region as a cohesive, bi-national whole. To address this need, build on existing water law, and engage the public, this article provides a blueprint to establish a Great Lakes Trail on the shores of the Great Lakes. The trail will link together 10,000 miles of coastline and provide the longest marked walking trail in the world. It will demarcate an already existing, yet largely unrecognized, public trust easement and engage the public with their common heritage in the lakeshore. The Great Lakes Trail is rooted in longstanding legal rights in the beach commons that have been forgotten and eroded over time. The trail provides a tangible way to restore the public’s coastal history and reinvigorate public trust rights.In the United States, when each of the Great Lakes states entered the Union, the federal government transferred to them the waters and lake beds of the Great Lakes up to the Ordinary High Water Mark on the beach. The states were to hold these lands and waters in trust for the public use and enjoyment. In 2005, the Michigan Supreme Court held in favor of the public’s right to access and walk along this beach. This is the only Great Lakes state court decision to directly address the public’s right to walk along the Great Lakes, and it provides an excellent contemporary model decision for the region. On the Canadian side of the Great Lakes there is an existing movement to build a Waterfront Trail along all of the Great Lakes and St. Lawrence River, as well as legislative efforts to recognize a right of passage on foot along the Great Lakes shoreline. However, the states and provinces lack consistency in how they address public access to this coast, and have not identified it as a broad public asset like the Appalachian Trail. Establishing the Great Lakes Trail will be a monumental effort, requiring a multidisciplinary approach. It will require generating local, and especially lakeshore property owners’ support for the trail; developing a system of local volunteers; working with artists and educators to design art installations and signs that reflect each community’s values and educate the public about Great Lakes ecological and legal issues; building local tourism economies with chambers of commerce to promote trailoriented businesses; and partnering with GIS mappers and App developers to produce real time local business information and mapping. Ultimately, getting people to utilize their public trust rights in walking the coasts of the Great Lakes engages them in actively seeing the importance of the Great Lakes as an ecological, political, economic, and cultural asset, which is a precursor to developing and implementing cooperative Great Lakes governance structures.

Notable decomposition products of senescing Lake Michigan Cladophora glomerata

Massive accumulations of Cladophora, a ubiquitous, filamentous green alga, have been increasingly reported along Great Lakes shorelines, negatively affecting beach aesthetics, recreational activities, public health and beachfront property values. Previously, the decomposition byproducts of decaying algae have not been thoroughly examined. To better understand the negative consequences and potential merit of the stranded Cladophora, a three month mesocosm study of the dynamic chemical environment of the alga was conducted using fresh samples collected from southern Lake Michigan beaches. Typical fermentation products, such as organic acids, sulfide compounds, and alcohols were detected in the oxygen–deprived algae. Short chain carboxylic acids peaked on day seven, in correspondence with the lowest pH value. Most low molecular mass carbon compounds were eventually consumed, but 4-methylphenol, indole, and 3-methylindole were detected throughout the incubation period. Natural oils were detected in fresh and decomposing algae, indicating the stable nature of these compounds. The mesocosm experiment was validated by directly sampling the fluid within decomposing Cladophora mats in the field; many of the same compounds were found. This study suggests that the problematic Cladophora accumulations may be harvested for useful byproducts, thereby reducing the odiferous and potentially harmful mats stranded along the shorelines.

Blueprint for the Great Lakes Trail

The Great Lakes are vast yet vulnerable. There is a need to focus the public’s attention on the significance of the lakes for the region as a cohesive, binational whole. To address this need, build on existing water law, and engage the public, this Article provides a blueprint to establish a Great Lakes Trail on the shores of the Great Lakes. The Trail will link together 10,000 miles of coastline and provide the longest marked walking trail in the world. It will demarcate an already existing, yet largely unrecognized, public trust easement and engage the public with their common heritage in the lakeshore. The Great Lakes Trail is rooted in longstanding legal rights in the beach commons that have been forgotten and eroded over time. The Trail will provide a tangible way to restore the public’s coastal history and reinvigorate public trust rights. In the United States, when each of the Great Lakes states entered the Union, the federal government transferred to them the waters and lakebeds of the Great Lakes up to the ordinary high water mark on the beach. The states were to hold these lands and waters in trust for the public use and enjoyment. In 2005, the Michigan Supreme Court held in favor of the public’s right to access and walk along this beach. This is the only Great Lakes state court decision to directly address the public’s right to walk along the Great Lakes, and it provides an excellent contemporary model decision for the region. On the Canadian side of the Great Lakes, there is an existing movement to build a Waterfront Trail along all of the Great Lakes and St. Lawrence River, as well as legislative efforts to recognize a right of passage on foot along the Great Lakes shoreline. However, the states and provinces lack consistency in how they address public access to this coast, and have not identified it as a broad public asset like the Appalachian Trail. Establishing the Great Lakes Trail will be a monumental effort, requiring a multidisciplinary approach. It will require generating local, and especially lakeshore property owners’ support for the Trail; developing a system of local volunteers; working with artists and educators to design art installations and signs that reflect each community’s values and educate the public about Great Lakes ecological and legal issues; building local tourism economies with chambers of commerce to promote trail-oriented businesses; and partnering with GIS mappers and app developers to produce real time local business information and mapping. Ultimately, allowing people to utilize their public trust rights in walking the coasts of the Great Lakes actively engages them in seeing the importance of the Great Lakes as an ecological, political, economic, and cultural asset, which is a precursor to developing and implementing cooperative Great Lakes governance structures.

Influence of topography, bare sand, and soil pH on the occurrence and distribution of plant species in a lacustrine dune ecosystem

Dune ecosystems along the Great Lakes shoreline provide essential habitat for specialized plant communities and several state and federal listed rare species. I conducted a vegetation survey in Grand Sable Dunes, Pictured Rocks National Lakeshore, MI, in an effort to investigate the hypothesis that physical dune characteristics influence the distribution of encountered listed species of concern. Three species with concern status were encountered (Cirsium pitcheri, Stellaria longipes, and Tanacetum bipinnatum). Overall plant diversity was negatively correlated with soil pH. Increases in dune aspect and slope resulted in increased abundance of C. pitcheri and S. longipes, while T. bipinnatum decreased in abundance. Increases in species richness and plant density resulted in decreased abundance of C. pitcheri and T. bipinnatum, while S. longipes increased in abundance. These three species rarely co-occurred in quadrats. The gradient of dune stabilization that has naturally occurred within Grand Sable Dunes provides the necessary range of distinct microhabitat necessary for C. pitcheri, S. longipes, and T. bipinnatum to establish and maintain populations. Younger foredunes with less vegetation cover are necessary for C. pitcheri and T. bipinnatum. As dunes stabilize and more species colonize, the microhabitat becomes more suitable for S. longipes. Ensuring a natural range of dune stabilization from active foredunes to stable hind dunes will benefit conservation of endangered, threatened, and species of concern.