Great Lakes Shoreline Research Articles

The deceptively complicated “elevation ordinary high water mark” and the problem with using it on a Laurentian Great Lakes shore

In 2013 the Laurentian Great Lakes are at historically low levels; but they will undoubtedly rise again as they always have in an ongoing pattern of seasonal, annual and decadal fluctuations. Those fluctuations, coupled with other physical dynamics unique to the Great Lakes system, will continue to shift shorelines lake-ward and land-ward dramatically over time, perhaps more so because of increased storminess from climate change. These shifting shores implicate legal doctrines that attempt to balance public interests and private property rights at the shore, and they complicate the Great Lakes states' efforts to effectively and fairly manage their Great Lakes shorelands. One challenge comes from using an elevation-based standard to mark ordinary high water, a method that is difficult conceptually to administer and that yields multiple marks over time. We describe briefly Great Lakes shoreline dynamics and the application of state Public Trust Doctrines to those shorelines, and we discuss in detail recent litigation in Michigan regarding use of an elevation-based standard to mark ordinary high water, illustrating the inherent problems with that standard. We conclude that the elevation-based standard should be abandoned, or if not abandoned applied in a manner to adequately safeguard public trust shorelands.

Monitoring land cover change in the Lake Superior basin

Consistent, repeatable and broadly applicable land use, land cover data is needed across the Lake Superior basin to facilitate ecosystem condition assessment and trend analysis. Such a data set collected regularly through time could inform and focus field monitoring efforts, and help prioritize restoration and mitigation efforts. Unfortunately, few data sets exist that are bi-nationally consistent in time, classification method, or resolution. To this end, we integrated land cover data across both the Canadian (Ontario Provincial Land Cover data) and US portions (National Land Cover Data) of the Lake Superior basin for two time steps (approximately 1992 and 2001) roughly one decade apart. After harmonizing landcover classes across the two datasets we compared the explicit amount and relative amount (total hectares and proportion of each area as percents) for each of the common land cover classes that occurred across the two time steps for the entire Lake Superior basin, for the U.S. portion of the Lake Superior basin only, and for the Canadian portion of the Lake Superior basin only. We also compared land cover change for the entire basin within a 1 km and a 10 km buffer of the Great Lakes shoreline. We then summarized and compared these land cover types for each time period across a common set of watersheds derived from elevation data (Hollenhorst et al., 2007) for the entire Lake Superior basin. This allowed us to identify and quantify the types of change occurring generally across the entire basin, more specifically across both the U.S. and Canadian portions of the basin, and more explicitly for near coastal areas and watersheds across the entire basin. Noteworthy changes were detected across the basin, particularly an increase in mixed forest types and a corresponding decrease in coniferous forest types.

Drawing Lines in Law Books and on Sandy Beaches: Marking Ordinary High Water on Michigan's Great Lakes Shorelines under the Public Trust Doctrine

In 1968 the Michigan Legislature adopted an elevation-based approach for discerning the ordinary high water mark (OHWM) along the state's Great Lakes shorelines pursuant to the public trust doctrine. In 2005 the Michigan Supreme Court reaffirmed that Michigan's public trust interest extends up to the OHWM, but it articulated a different standard for discerning that OHWM, noting in passing that the state's statutory standard relates only to certain regulatory authorities. The court left unresolved the questions of exactly how these two methods of marking ordinary high water relate to one another and precisely how far up the shore the state's authorities to regulate private shoreline development extends. We first describe how the Great Lakes states, including Michigan, have adapted the public trust doctrine to their Great Lakes shorelines, particularly in terms of demarcating boundaries. We then discuss attributes of the Great Lakes that make those efforts problematic and present original data on changing water levels and shoreline profiles along Lake Michigan over time. Based on that analysis, we conclude that while use of an OHWM on Great Lakes shorelines makes sense, the state's statutory elevation-based OHWM standard makes little sense given Great Lakes shoreline dynamics. We identify further legal and policy issues the state will likely confront as it attempts to mark OHW in the foreseeable future given both the state of the law and the nature of the Great Lakes.

Productivity, embryo and eggshell characteristics, and contaminants in bald eagles from the Great Lakes, USA, 1986 to 2000

Chlorinated hydrocarbon concentrations in eggs of fish-eating birds from contaminated environments such as the Great Lakes of North America tend to be highly intercorrelated, making it difficult to elucidate mechanisms causing reproductive impairment, and to ascribe cause to specific chemicals. An information- theoretic approach was used on data from 197 salvaged bald eagle (Haliaeetus leucocephalus) eggs (159 clutches) that failed to hatch in Michigan and Ohio, USA (1986-2000). Contaminant levels declined over time while eggshell thickness increased, and by 2000 was at pre-1946 levels. The number of occupied territories and productivity increased during 1981 to 2004. For both the entire dataset and a subset of nests along the Great Lakes shoreline, polychlorinated biphenyls (SigmaPCBs, fresh wet wt) were generally included in the most parsimonious models (lowest-Akaike's information criterion [AICs]) describing productivity, with significant declines in productivity observed above 26 microg/g SigmaPCBs (fresh wet wt). Of 73 eggs with a visible embryo, eight (11%) were abnormal, including three with skewed bills, but they were not associated with known teratogens, including SigmaPCBs. Eggs with visible embryos had greater concentrations of all measured contaminants than eggs without visible embryos; the most parsimonious models describing the presence of visible embryos incorporated dieldrin equivalents and dichlorodiphenyldichloroethylene (DDE). There were significant negative correlations between eggshell thickness and all contaminants, with SigmaPCBs included in the most parsimonious models. There were, however, no relationships between productivity and eggshell thickness or Ratcliffe's index. The SigmaPCBs and DDE were negatively associated with nest success of bald eagles in the Great Lakes watersheds, but the mechanism does not appear to be via shell quality effects, at least at current contaminant levels, while it is not clear what other mechanisms were involved.

Importance of Coastal Change Variables in Determining Vulnerability to Sea- and Lake-Level Change

Abstract In 2001, the U.S. Geological Survey began conducting scientific assessments of coastal vulnerability to potential future sea- and lake-level changes in 22 National Park Service sea- and lakeshore units. Coastal park units chosen for the assessment included a variety of geological and physical settings along the U.S. Atlantic, Pacific, Gulf of Mexico, Gulf of Alaska, Caribbean, and Great Lakes shorelines. This research is motivated by the need to understand and anticipate coastal changes caused by accelerating sea-level rise, as well as lake-level changes caused by climate change, over the next century. The goal of these assessments is to provide information that can be used to make long-term (decade to century) management decisions. Here we analyze the results of coastal vulnerability assessments for several coastal national park units. Index-based assessments quantify the likelihood that physical changes may occur based on analysis of the following variables: tidal range, ice cover, wave height,...

Multiscale relationships between Great Lakes nearshore fish communities and anthropogenic shoreline factors

The multi-scale nature of streams, rivers, and inland lakes is well documented, although relationships between the ecology of Great Lakes nearshore areas and shoreline processes are generally poorly described. Given the high levels of development pressure currently exerted on Great Lakes shorelines, we sought to determine whether patterns exist between measures of shoreline development quantified at multiple spatial scales and adjacent fish community measures. We expected that fish measures for nearshore areas immediately adjacent to intact versus modified shorelines would differ as a result of the greater buffering capacity of the intact shorelines. Further, we expected anthropogenic shoreline factors to act cumulatively in combination with prevailing currents to influence fish communities in downdrift nearshore areas. Our results indicated that a few shallow water and nearshore fish community measures exhibited significant patterns that may be attributable to immediately adjacent shoreline characteristics. In addition, several fish measures were related to urban-residential land uses and shore structure numbers of updrift shoreline areas, suggesting that cumulative anthropogenic factors operating over larger spatial scales also influence local fish communities. Based on these results, we argue that there is critical need for multi-scale management strategies for shorelines that address the potential for both local and cumulative, larger-scale environmental impacts relative to local nearshore biota.

The scale-dependent importance of habitat factors and dispersal limitation in structuring Great Lakes shoreline plant communities

Niche-based and neutral models of community structure posit distinct mechanisms underlying patterns in community structure; correlation between species’ distributions and habitat factors points to niche assembly while spatial pattern independent of habitat suggests neutral assembly via dispersal limitation. The challenge is to disentangle the relative contributions when both processes are operating, and to determine the scales at which each is important. We sampled shoreline plant communities on an island in Lake Michigan, varying the extent and the grain of sampling, and used both distance-based correlation methods and variance partitioning to quantify the proportion of the variation in plant species composition that was attributable to habitat factors and to spatial configuration independent of habitat. Our results were highly scale dependent. We found no distance decay of plant community similarity at the island scale (1−33 km). All of the explained variation (32%) in species composition among samples at this scale was attributed to habitat factors. However, at a site intensively sampled at a smaller scale (5−1,200 m), similarity of species composition did decay with distance. Using a coarse sampling grain (transects), habitat factors explained 40% of the variation, but the purely spatial component explained a comparable 22%. Analyzing plots within transects revealed variation in species composition that was still jointly determined by habitat and spatial factors (18 and 11% of the variance, respectively). For both grain sizes, most of the habitat component was spatially structured, reflecting an abrupt alongshore transition from sandy dunes to cobble beach. Space per se explained more variation in species composition at a second site where the habitat transition was more gradual; here, habitat acted as a less selective filter, allowing the signal of dispersal limitation to be detected more readily. We conclude that both adaptation to specific habitat factors and habitat-independent spatial position indicative of dispersal limitation determine plant species composition in this system. Our results support the prediction that dispersal limitation—a potentially, but not necessarily, neutral driver—is relatively more important at smaller scales.

Stable Nitrogen Isotopes of Plankton and Benthos Reflect a Landscape-level Influence on Great Lakes Coastal Ecosystems

As populations and human activities increase in coastal watersheds, an understanding of the connections of aquatic ecosystems to the adjacent terrestrial landscape is necessary to identify, monitor, and protect vulnerable coastal habitats. This study investigates the relationships between land-use patterns and δ 15N values of aquatic organisms in coastal ecosystems, across a defined watershed gradient for the U.S. portion of the Great Lakes shoreline. δ 15N measured in plankton and benthic invertebrates reflects a range of basin wide land-use gradients and demonstrates a strong connection between watershed-based anthropogenic activities and exposure in aquatic biota. For example, benthos δ 15N values range over 12‰ across sites in our study, but regression analyses suggest that over 50% of the variability is explained by the regional landscape. Further, multiple taxa at comparable trophic position showed similar patterns in relation to watershed-scale land use. Our results suggest that within the coastal environment, the expression of landscape in aquatic biota is stronger in habitats such as embayments and wetlands than open nearshore. These results support the use of δ 15N in Great Lakes coastal biota as an exposure indicator of watershed-scale N loading.

Use of IKONOS Imagery to Map Coastal Wetlands of Georgian Bay

Abstract Wetlands throughout North America have been diminished in quantity and quality because of human activities, and it is therefore important that fishery managers monitor changes in supply of this critical fish habitat. Use of traditional field-based methods to detect and record the change in aquatic vegetation in Great Lakes wetlands is a daunting task because wetlands are extensive and widely distributed along the Great Lakes shoreline. Mapping wetlands for such a large geographic area necessitates the use of remote sensing technology to obtain an accurate inventory of these ecosystems. The objective of this study was to explore the capabilities of using IKONOS satellite imagery to map different types of aquatic vegetation and habitat features in Great Lakes wetlands. We acquired imageries for Fathom Five National Marine Park in Lake Huron and an area of eastern Georgian Bay in 2002 and chose 11 wetlands for habitat mapping with remote sensing software. The comparison of results of the image analy...

Nearshore Community Characteristics Related to Shoreline Properties in the Great Lakes

Successful protection and restoration of Great Lakes nearshore ecosystems will likely rely on management of terrestrial resources along Great Lakes shorelines. However, relationships between biological communities and changing shoreline environmental properties are poorly understood. We sought to begin understanding the potential roles of shoreline geomorphological and land cover properties in structuring nearshore biological communities in the Laurentian Great Lakes. Despite high variability in densities (benthic macroinvertebrates and zooplankton) and catch per unit effort (CPUE, shallow water and nearshore fish) within and among lake areas, several biological community patterns emerged to suggest that nearshore aquatic communities respond to shoreline features via the influences of these features on nearshore substrate composition and stability. Benthic macroinvertebrate densities were not different between shoreline types, although they were generally lower at nearshore sites with less stable substrates. Shallow water fish CPUE and zooplankton densities were generally lower for nearshore areas adjacent to developed mid-bluff shorelines and sites characterized by less stable substrates. Larger fish CPUE appeared to be unresponsive to local shoreline and substrate properties of nearshore zones. The emergence of these patterns despite significant ecological differences among lake areas (e.g., productivity, community composition, etc.) suggests that shoreline development may have comparable influences on nearshore ecosystems throughout the Great Lakes, providing a terrestrialbased indicator of relative nearshore biological and ecological integrity.

Influence of shoreline features on fish distribution in the Laurentian Great Lakes

In this paper, we used assembled fish distributions (over 9500 field observations) and correlated them with 11 categories of the Great Lakes shoreline (i.e., bedrock, bluff, coarse beach, sandy beach – dune, sandy–silty bank, clay bank, low riverine – coastal plain, composite, wetland, artificial, and unclassified) to validate the appropriateness of classifying Great Lakes fishes into three species complexes (taxocenes) that account for differences in their dependence on shoreline features. A χ2 goodness-of-fit test with Bonferroni correction indicated a significant positive association between the presence of fish and three shoreline classes: wetland, sandy beach – dune, and bluff. The Dutilleul modified t test was used to quantify the correlation between wetlands and distribution of the 25 most abundant species and those of different functional groupings. Our results confirm that (i) the Great Lakes fish community utilizes certain shoreline features (especially wetlands) disproportionately to their availability, (ii) the distribution of wetland-associated taxa is influenced by wetland type (i.e., protected embayment versus open-shoreline wetland), and (iii) the preferred utilization of coastal wetlands by a majority of the fish community is consistent across geographical scales, from the local site to the entire Great Lakes shoreline.

Plants as regional indicators of Great Lakes coastal wetland health

In this paper we explore the potential for developing plant-based indicators for key dimensions of wetland stress, including 1) hydrologic flow modification (through water-level regulation and diking), 2) water quality degradation (through nutrient loading and sedimentation), and 3) ecological structural breakdown or physical degradation. Based on a review of the literature, we identify species or species groups that potentially function as indicators of individual dimensions of anthropogenic stress and propose floristic metrics for monitoring wetland health. We then examine the utility of these metrics for evaluating wetland disturbance at both regional and local scales, utilizing a database of wetland sites spanning the entire U.S. Great Lakes shoreline. We conclude that multiple dimensions of wetland disturbance can be measured based on coverage values of key aquatic plants.

News Briefs: Erosion will consume one quarter of all homes within 500 feet of America's oceans and Great Lakes shorelines over the next 60 years,

News Briefs: Erosion will consume one quarter of all homes within 500 feet of America's oceans and Great Lakes shorelines over the next 60 years,

Isozyme diversity in Iris Cristata and the threatened glacial endemic I. Lacustris (Iridaceae)

Iris cristata and I. lacustris differ markedly in geographic distribution, glacial history of current ranges, and ecology. We hypothesized that I. cristata, a widespread species of unglaciated regions of eastern North America, would exhibit genetic diversity typical of other widespread plant species, whereas the threatened I. lacustris, which occupies glaciated habitats on Great Lakes shorelines, would display little genetic variation. Iris lacustris lacked detectable polymorphisms in 18 isozyme loci, although we found evidence of possible incomplete gene silencing in four additional loci in some populations. In contrast, I. cristata was polymorphic at 73% of 15 loci examined, with an average of three alleles per locus. Genetic diversity (H(e)) was 0.231. All species-level and population-level estimates of genetic diversity were higher than averages for plants having comparable life history traits. Nearly 98% of the total genetic diversity in I. cristata was apportioned within populations, and heterozygosity and fixation estimates suggest a high level of outcrossing in this species (t = 1.265). The long-lived perennial habit and high outcrossing rate in stable populations are proposed as factors contributing to high genetic diversity in I. cristata. The data are consistent with an hypothesis of a recent origin of I. lacustris from a very limited I. cristata gene pool exacerbated by repeated bottlenecks and founder effects as I. lacustris populations were displaced by lake-level changes over the past 11 000 yr.

Ontario‐great lakes shoreline management: An update

The growth of international experience with integrated coastal zone management (ICZM) since the United Nations Conference on Environment and Development in 1992 provides an opportunity to apply new concepts to assist a variety of coastal regions facing similar management concerns and issues. Significant political and social changes within the province of Ontario in Canada are resulting in important and fundamental impacts on existing Great Lakes shoreline management policies and programs. Reforms to the Planning Act alter the role of the provincial government in land use planning and place increased responsibilities with local municipalities. Funding cutbacks and program reductions have removed staff and support from the Great Lakes Shoreline Management Program, endangering its very future. Recent management initiatives by the Toronto Waterfront Regeneration Trust suggest the potential for the application of concepts and principles from ICZM on the Great Lakes. There is a need for improved leadership and direction by all levels of government, as well as by communities and citizens, in efforts to incorporate concepts and experience from current initiatives in ICZM. This will allow for the development of a stronger, more effective, and more efficient approach for Great Lakes shoreline management in Ontario based on concepts and practices related to ICZM.

Assessing the Impact of Climate Change on the Great Lakes Shoreline Wetlands

Great Lakes shoreline wetlands are adapted to a variable water supply. They require the disturbance of water level fluctuations to maintain their productivity. However, the magnitude and rate of climate change could alter the hydrology of the Great Lakes and affect wetland ecosystems. Wetlands would have to adjust to a new pattern of water level fluctuations; the timing, duration, and range of these fluctuations are critical to the wetland ecosystem response. Two "what if" scenarios: (1) an increased frequency and duration of low water levels and (2) a changed temporal distribution and amplitude of seasonal water levels were developed to assess the sensitivity of shoreline wetlands to climate change. Wetland functions and values such as wildlife, waterfowl and fish habitat, water quality, areal extent, and vegetation diversity are affected by these scenarios. Key wetlands are at risk, particularly those that are impeded from adapting to the new water level conditions by man-made structures or geomorphic conditions. Wetland remediation, protection and enhancement policies and programs must consider climate change as an additional stressor of wetlands.

Integrated coastal zone management and the Great Lakes

Integrated coastal zone management (ICZM) has developed over the last several years as a major international initiative resulting from the 1992 United Nations Conference on Environment and Development. The concept is based on an attempt to develop an uniform management framework for a comprehensive approach to all the sectoral activities that effect the coastal zone. The development of Great Lakes coastal (or shoreline) management plans by the US state governments and the province of Ontario largely fail to address the range of issues and mechanisms considered as essential components of ICZM. The preparation of management plans needs to reflect a stronger attempt to develop a broader ecosystem approach with linkages to human activities and impacts and address the variety of urban and rural land use concerns characteristic of the Great Lakes shoreline.

Prehistoric, historic, and present settlement patterns related to ecological hierarchy in the Eastern Upper Peninsula of Michigan, U.S.A.

The distribution of human occupation across a landscape provides informationabout how people use the landscape, about patterns of economic development,and about social interactions of human groups. When the distributions areexamined over several thousand years, we gain an evolutionary understanding,not only of the people and their cultural patterns, but also of physicallandscape development. The focus of this assessment was to examine andcompare settlement patterns of prehistoric, historic, and present timeperiods, based on known cultural sites in the Eastern Upper Peninsula ofMichigan, U.S.A., and to generate hypotheses about the interaction ofsettlement pattern and landscape change at multiple scales. Patterns ofsettlement among the three time periods were compared at three geographicscales: by subregional ecosystems, by landscape ecosystems and by terraincharacteristics. The Michigan Bureau of History database of archaeologicalsites was searched for prehistoric habitation sites of Middle or LateWoodland period (ca. 3000-300 years before present). Historic occupationswere drawn from pre-European settlement landscape data based on General LandOffice survey notes of the 1850s. We extracted “urban” categories from landcover classified from Landsat Thematic Mapper imagery to measure presentoccupations. Spatial patterns and dynamics of settlement areas in each timeperiod were examined using the ARC/INFO geographic information system (GIS).Results showed a tendency for settlement in all time periods on the bedrockand lowland landscape groups near Great Lakes shorelines, generally occupyingslopes less than two percent. The distribution of present occupations, interms of both slope aspect and geographic subregion (multi-scalar), wassimilar to the distribution of prehistoric occupations. Both prehistoric andpresent sites were primarily south facing and were frequently found alongGreen Bay and Lake Michigan shorelines.

Development of Great Lakes shoreline management plans by Ontario conservation authorities

The Great Lakes shoreline in Ontario is subject to severe flooding and erosion due to frequent high water level periods and storm events leading to wind and wave action. After extensive property damages in 1985 and 1986, the province established a shoreline management program to be administered by the Ontario Ministry of Natural Resources. A key component of this program is the development of Great Lakes shoreline management plans by Ontario conservation authorities. A review of three such plans reveals a focus on understanding the range and frequency of shoreline flooding and erosion, and the use of land use regulations and shoreline protection structures to reduce the impact from these hazards. Limited attention and responses are provided for the range of issues and concerns that occur in these shoreline areas such as ecosystem management, species and habitat protection, and water quality. A lack of consistency, enforcement, monitoring and coordination occurs in the provincial program which has also recently been affected by related land use and environmental planning initiatives and government financial restraints.

Land‐use planning reform in Ontario: Implications for great lakes shoreline management

Recent planning reform in Ontario has focused on an interest in ecosystem based land‐use planning and management and will have significant impacts on the provincial Great Lakes shoreline management program. Since the high water levels on the Great Lakes during 1985/86, the Ontario Ministry of Natural Resources (OMNR) and local conservation authorities (CAs) have been developing provincial policy and management plans to reduce property damage from flooding and erosion that occurs during frequent high‐water‐level events. The program reflects the long‐standing interest in use of municipal land‐use zoning regulations to control shoreline development in areas prone to flooding and erosion. Provincial land‐use planning reform underway since 1991 will have important implications by requiring a greater focus on land‐use and environmental issues. Important lessons can be learned from the experience in Ontario with regard to coastal zone management in other regions where land‐use planning can be greater linked to e...