Flowering rush (Butomus umbellatus L.) is an emergent perennial monocot that has invaded aquatic systems along the U.S. - Canadian border. Currently, there are two known cytotypes of flowering rush, diploid and triploid, within the invaded range. Although most studies have focused on the triploid cytotype, little information is known about diploid plants. Therefore, phenology and resource allocation were studied on the diploid cytotype of flowering rush in three study sites (Mentor Marsh, Ohio; Tonawanda Wildlife Management Area, New York; and Unity Island, New York) to understand seasonal resource allocation, environmental influences on growth, and to optimize management strategies. Samples were harvested once a month from May to November at each site from 2021 to 2023. Plant metrics were regressed to air temperature, water temperature, and water depth. Aboveground biomass peaked from July-September and comprised 50 to 70% of total biomass. Rhizome biomass peaked from September to November and comprised 40 to 50% of total biomass. Rhizome bulbil densities peaked from September to November at 3,000 to 16,000 rhizome bulbils m-2. Regression analysis resulted in strong negative relationships between rhizome starch content and air temperature (r2=0.52) and water temperature (r2=46). Other significant, though weak, relationships were found including a positive relationship between aboveground biomass and air temperature (r2=0.17), a negative relationship between rhizome bulbil biomass and air temperature (r2=0.18) and a positive relationship between leaf density and air temperature (r2=0.17). Rhizomes and rhizome bulbils combined stored up to 60% of total starch and present a unique challenge to management as these structures cannot be reached directly with herbicides. Therefore, management should target the aboveground tissue before peak production (July) to reduce internal starch storage and aim to limit regrowth over several years.

The eastern Great Lakes Late Quaternary timescale is based on older thermoluminescence dates and on uncalibrated radiocarbon dates from extensive sections along the north shores of Lakes Erie and Ontario. New optically stimulated luminescence dates from Late Quaternary delta sediments from the north shores of Lake Erie at Sand Hills Park give consistent ages of 23.5 to 20.5 ka. This is 4 to 7 ka older than previously assigned based on lithologic correlation with 16.5 ka calibrated radiocarbon dated sediments 5 km to the west at Vanderven. On the existing eastern Great Lakes stratigraphy, it puts deposition of these Sand Hills Park sediments in the Erie interstadial and not in the fluctuating postglacial glacial retreat of the Mackinaw phase to which the Vanderven sediments belong. The Sand Hills delta and underlying diamicts must have been overridden by the Porty Bruce advance at 18 ka. IntCal20 calibration of existing radiocarbon ages suggests that the physical stratigraphic relations of the various Wisconsin units are accurate and that the existing timescale is simply too young.

This paper presents research on the benefits of removing legacy pollutants in Great Lakes Areas of Concern (AOCs). AOCs are heavily polluted coastal locations identified as priorities for restoration under the Great Lakes Water Quality Agreement (GLWQA) between the United States and Canada. Legacy pollutants pose a human and environmental health risk that can limit opportunities for redevelopment, recreation, and wildlife habitats. The AOC program improves water quality through remediation and restoration projects, which may increase the desirability of living in proximity to AOCs. In this paper, we estimate the economic benefit of cleaning up part of the Milwaukee Estuary AOC with a two-part sorting model using panel data on neighborhood populations and moving decisions before and after a series of remediation actions. Our results provide evidence that residents value remediation, though estimates are sensitive to the definition of the cleanup area. The average annual benefit for a household living near the AOC just downstream of cleanup is $268, with a range of $28-$499 depending on their race and tenure group; the aggregate benefit is $350 million. Results indicate a large difference in benefits between renters and owners but statistically insignificant differences between race groups.

This paper estimates the effect of environmental remediation on housing prices in the Milwaukee Estuary Area of Concern (AOC) using a hedonic analysis of individual arms-length sales before and after a major remediation action between 2011 and 2015. Our design leverages this before-after comparison as well as the proximity of homes to remediation and the AOC boundary. Measuring the effect of AOCs in the housing market has always been a difficult task, given that water in AOCs can provide a mix of amenities and disamenities. Indeed, we find little evidence of a negative proximity effect when applying hedonic analysis to cross-section data. However, when we apply the analysis to a repeated cross section in a quasi-experimental framework, we find statistically significant evidence that living near the affected part of the AOC became more desirable after cleanup.

A unique regional climate progression, ca 14.2–11.5 cal ka BP, in the eastern Great Lakes region of North America is suggested by subfossil logs, high-resolution 14C dates, and established proxy records in New York, USA. The progression began with a northern boreal-type climate ca. 14.2–13.1 ka coeval with the expansion of Lake Iroquois, a transition to a southern boreal-type climate ~13.1–12.9 ka that coincided with the transition of Lake Iroquois into progressively lower lake levels, and a continuation of the southern boreal-type climate ~12.9–11.5 ka. These conditions and changes are evident in the tree rings and relative dominance of tamarack (Larix laricina) and spruce species (Picea spp.) plus the presence of black ash (Fraxinus nigra) as the only thermophilous species. Together they suggest variations in atmospheric moisture levels, surface winds, temperature extremes, and/or an enhanced seasonality over time. Here we propose that the evolution of the glacial Great Lakes and their interactions with ice sheets, meltwater, winds, and regional topography created a regional glacial lake-effect climate, 14.2–11.5 cal ka BP, that was opposite to the established warming Bølling-Allerød–cold Younger Dryas climate progression.

The round goby (Neogobius melanostomus) is a successful invader of the Great Lakes–St Lawrence River basin that harbours a number of local parasites. The most common are metacercariae of the genus Diplostomum. Species of Diplostomum are morphologically difficult to distinguish but can be separated using molecular techniques. While a few species have been sequenced from invasive round gobies in this study system, their relative abundance has not been documented. The purpose of this study was to determine the species composition of Diplostomum spp. and their relative abundance in round gobies in the St Lawrence River by sequencing the barcode region of cytochrome c oxidase I. In 2007–2011, Diplostomum huronense (=Diplostomum sp. 1) was the most common, followed in order by Diplostomum indistinctum (=Diplostomum sp. 4) and Diplostomum indistinctum sensu Galazzo, Dayanandan, Marcogliese & McLaughlin (2002). In 2012, the most common species infecting the round goby in the St Lawrence River was D. huronense, followed by D. indistinctum and Diplostomum gavium (=Diplostomum sp. 3). The invasion of the round goby in the St Lawrence River was followed by a decline of Diplostomum spp. in native fishes to low levels, leading to the previously published hypothesis that the presence of the round goby has led to a dilution effect. Herein, it is suggested that despite the low infection levels in the round goby, infections still may lead to spillback, helping to maintain Diplostomum spp. in native fishes, albeit at low levels.

Greenock Swamp wetland complex is one of few remaining natural wetlands in the Great Lakes region and, at 89 km2 in areal extent, is currently the largest hardwood swamp in southern Ontario, Canada. We present here pollen and sediment records from a kettle hole (Schmidt Lake) and adjacent Thuja occidentalis swamp to reconstruct regional paleoclimate and vegetation history, and to assess the timing and development of the swamp ecosystem and associated carbon stocks. Pollen-inferred paleoclimate reconstructions show the expected warming in the Early Holocene, and indicate the Mid-Holocene initiation of lake-effect snow. This enhanced snowfall may have maintained high water tables in the adjacent wetland since ca. 8300 years ago, promoting the establishment of a swamp dominated by Thuja occidentalis. Carbon accumulation rates in a >2-m-long peat core collected from a Thuja occidentalis stand adjacent to Schmidt Lake are 30–40 g C/m2/yr, which is higher than the average of northern high-latitude peatlands. Using topographic and hydrological parameters, we estimated that mean swamp peat thicknesses could exceed 2 m. Thus, this study encourages future investigations on temperate swamps from the perspective of hitherto underestimated Holocene carbon sinks and shows the importance of regional hydroclimate in supporting swamp ecosystems.

Other-than-human persons and the role they play in transforming social, economic, and ideological material realities is an area of expanding interest in archaeology. Although the Anishinaabeg were an early and vital focus of cultural anthropological studies on nonhumans given their significant relationships with other-than-human persons, known to them as manitou, emerging archaeologies advancing this topic are not largely centered on ancestral Anishinaabeg sites and artifacts. This article analyzes a set of nonvessel ceramic artifacts from Late Woodland archaeological sites in the Inland Waterway in northern Michigan, which are interpreted to be ceramic renderings of manitou. I argue that these were manitou-in-clay, vibrant relational entities that are brought into being for and through use in ceremonial perspective practices related to Mishipishu—a complexly powerful, seductive, and dangerous nonhuman being known as the head of all water spirits. I contextualize the making and breaking of Mishipishu manitou-in-clay as acts of petition by hunter-fishers who had been seduced by this manitou in dreams, as they headed out on necessary but high-risk early-spring resource harvesting in the inland lakes of the Inland Waterway. This case advances insights into how relationships with other-than-human persons were coproductive of the world in the northern Great Lakes region during the Late Woodland period.

This article explores the environmental and market determinants of irrigation management in a five-state Great Lakes region. We found evidence that corn, soybean, and potato irrigators respond to the cost of water at the intensive margin. Evidence of a water-cost effect at the extensive margin was mixed. This article is unique in its geographic focus and its consideration of various temperature effects. We found evidence of a long-run average temperature effect on crop acreage allocation decisions and a short-run extreme heat effect on water application rates.

Until now, availability of wood from the Younger Dryas abrupt cooling event (YDE) in N. America ca. 12.9 to 11.6 ka has been insufficient to develop high-resolution chronologies for refining our understanding of YDE conditions. Here we present a multi-proxy tree-ring chronology (ring widths, “events” evidenced by microanatomy and macro features, stable isotopes) from a buried black spruce forest in the Great Lakes area (Liverpool East site), spanning 116 yr at ca. 12,000 cal yr BP. During this largely cold and wet period, the proxies convey a coherent and precise forest history including frost events, tilting, drowning and burial in estuarine sands as the Laurentide Ice Sheet deteriorated. In the middle of the period, a short mild interval appears to have launched the final and largest episode of tree recruitment. Ultimately the tops of the trees were sheared off after death, perhaps by wind-driven ice floes, culminating an interval of rising water and sediment deposition around the base of the trees. Although relative influences of the continental ice sheet and local effects from ancestral Lake Michigan are indeterminate, the tree-ring proxies provide important insight into environment and ecology of a N. American YDE boreal forest stand.

Directly dated Cucurbita from archaeological sites near Lake Huron expand the range and human usage of adventive, cultivated wild gourds or squash into the Great Lakes region, USA, by 4000 14C yr BP. The data also show that domesticated C. pepo squash was cultivated there by 3000 14C yr BP. Although milder Hypsithermal climate may have been a contributing factor, squash and gourds expanded northward during the mid-Holocene mainly by human agency and may be the first human-introduced adventive plant in temperate North America. Even after 3000 14C yr BP, when domesticated squash generally replaced wild varieties at northern sites, squash stands were probably informally managed rather than intensively cultivated.

Proglacial lakes, formed during retreat of the Laurentide ice sheet, evolved quickly as outlets became ice-free and the earth deformed through glacial isostatic adjustment. With high-resolution digital elevation models (DEMs) and GIS methods, it is possible to reconstruct the evolution of surface hydrology. When a DEM deforms through time as predicted by our model of viscoelastic earth relaxation, the entire surface hydrologic system with its lakes, outlets, shorelines and rivers also evolves without requiring assumptions of outlet position. The method is applied to proglacial Lake Oshkosh in Wisconsin (13,600 to 12,900 cal yr BP). Comparison of predicted to observed shoreline tilt indicates the ice sheet was about 400 m thick over the Great Lakes region. During ice sheet recession, each of the five outlets are predicted to uplift more than 100 m and then subside approximately 30 m. At its maximum extent, Lake Oshkosh covered 6600 km2 with a volume of 111 km3. Using the Hydrologic Engineering Center-River Analysis System model, flow velocities during glacial outburst floods up to 9 m/s and peak discharge of 140,000 m3/s are predicted, which could drain 33.5 km3 of lake water in 10 days and transport boulders up to 3 m in diameter.

We investigate seasonal variations in the diet and drinking water of four Great Lakes mastodon (Mammut americanum) specimens using stable isotope analysis of serially sampled inner-enamel bioapatite structural carbonate (δ13Csc, δ18Osc), and previously published bulk analyses. Isotopic analyses and thin section measurements showed that mastodon tooth enamel extension rates (~ 12–4 mm/yr, decreasing toward the cervix) were lower than those of mammoths or modern elephants. Mastodons had distinct and highly regular seasonal variations in δ13Csc and δ18Osc, which we interpret in the context of local glacial history and vegetation changes. Seasonal variations in δ18O were large but variations in δ13C were small, and may have been obscured if coarser sampling methods than our inner-enamel sampling approach were used. Thus, our approach may be particularly useful for understanding relatively small seasonal changes in δ13C within C3 environments. The seasonal patterns, though not entirely conclusive, suggest that the Ontario mastodons did not migrate over very long distances. Rather, the climate and seasonal dietary patterns of mastodons within the region changed over time, from ~ 12,400 to 10,400 14C yr BP (~ 15,000 – 12,000 cal yr BP). Insights gained using these methods can contribute to a better understanding of megafaunal extinctions and Paleoamerican lifeways.

Between 10,500 and 9000 cal yr BP, δ18O values of benthic ostracodes within glaciolacustrine varves from Lake Superior range from − 18 to − 22‰ PDB. In contrast, coeval ostracode and bivalve records from the Lake Huron and Lake Michigan basins are characterized by extreme δ18O variations, ranging from values that reflect a source that is primarily glacial (∼ − 20‰ PDB) to much higher values characteristic of a regional meteoric source (∼ − 5‰ PDB). Re-evaluated age models for the Huron and Michigan records yield a more consistent δ18O stratigraphy. The striking feature of these records is a sharp drop in δ18O values between 9400 and 9000 cal yr BP. In the Huron basin, this low δ18O excursion was ascribed to the late Stanley lowstand, and in the Lake Michigan basin to Lake Agassiz flooding. Catastrophic flooding from Lake Agassiz is likely, but a second possibility is that the low δ18O excursion records the switching of overflow from the Lake Superior basin from an undocumented northern outlet back into the Great Lakes basin. Quantifying freshwater fluxes for this system remains difficult because the benthic ostracodes in the glaciolacustrine varves of Lake Superior and Lake Agassiz may not record the average δ18O value of surface water.

This paper explores the use of functional benefits transfer to forecast the effects of waste sites on property values. The results of a meta-analysis of hedonic studies of waste sites are coupled with spatial analysis techniques to produce estimates of the effects of toxic contamination in Areas of Concern (AOCs) in the U.S. Great Lakes. Based on U.S. Census data for median home values, the methods used here suggest that approximately S5.2 billion (2005 dollars) have been lost in residential property values surrounding twenty-three of the AOCs. This compares to estimates that place the cost of remediation of all U.S. AOCs at up to $4.5 billion (2005 dollars). The case study also identifies issues surrounding the use of a meta-analysis with hedonic property value studies to support functional transfer.

Establishing reliable methods for the identification of benthic chironomid communities is important due to their significant contribution to biomass, ecology and the aquatic food web. Immature larval specimens are more difficult to identify to species level by traditional morphological methods than their fully developed adult counterparts, and few keys are available to identify the larval species. In order to develop molecular criteria to identify species of chironomid larvae, larval and adult chironomids from Western Lake Erie were subjected to both molecular and morphological taxonomic analysis. Mitochondrial cytochrome c oxidase I (COI) barcode sequences of 33 adults that were identified to species level by morphological methods were grouped with COI sequences of 189 larvae in a neighbor-joining taxon-ID tree. Most of these larvae could be identified only to genus level by morphological taxonomy (only 22 of the 189 sequenced larvae could be identified to species level). The taxon-ID tree of larval sequences had 45 operational taxonomic units (OTUs, defined as clusters with >97% identity or individual sequences differing from nearest neighbors by >3%; supported by analysis of all larval pairwise differences), of which seven could be identified to species or ‘species group’ level by larval morphology. Reference sequences from the GenBank and BOLD databases assigned six larval OTUs with presumptive species level identifications and confirmed one previously assigned species level identification. Sequences from morphologically identified adults in the present study grouped with and further classified the identity of 13 larval OTUs. The use of morphological identification and subsequent DNA barcoding of adult chironomids proved to be beneficial in revealing possible species level identifications of larval specimens. Sequence data from this study also contribute to currently inadequate public databases relevant to the Great Lakes region, while the neighbor-joining analysis reported here describes the application and confirmation of a useful tool that can accelerate identification and bioassesment of chironomid communities.