Ecological data as a resource for invasive species management in U.S. Great Lakes coastal wetlands

The coordinated use of ecological data is critical to the proper management of invasive species in the coastal wetlands of the Laurentian Great Lakes. Researchers and government programs have been increasingly calling for the use of data in management activities to increase the likelihood of success and add transparency in decision making. Web-enabled databases have the potential to provide managers working in Great Lakes coastal wetlands with relevant data to support management decisions. To assess the potential value of these databases to managers in Laurentian Great Lakes states, we surveyed wetland managers to determine their current data usage as well as their future data interests and catalogued the online databases currently available. Surveys were disseminated via email to managers in 56 different organizations overseeing invasive species management efforts in Great Lakes coastal wetlands; 46 responses were included in this analysis. Of the survey respondents, all reported using raw biotic data for decision making, (i.e. presence of target species) but many indicated that they would prefer to incorporate a greater variety of data, as well as more complex information. Our survey found that managers used web-enabled databases, but most databases that we catalogued only provided presence data for wetland biota. We concluded that databases can provide the types of data sought by invasive species managers but have unmet potential to be integrated into responsive management processes.     

Large-Scale Storm Damage on the U.S. Shores of the Great Lakes

Storm Data from the National Oceanic and Atmospheric Administration provides a data set for examining the spatial and temporal distribution of storm damage caused by large-scale, cyclonic storms on the U.S. shoreline of the Great Lakes for the period 1959–1990. On average, damage reports are much more frequent during high lake levels. Seasonally, the number reaches a maximum in November, declines during the winter months, and reaches a secondary maximum in April. This decrease in the winter months may be due to the protective ice cover on the lakes. Although Michigan received the most damage reports, Illinois, New York, and Ohio have a higher density of reports. Lake Erie and Lake Michigan are most frequently mentioned in the reports. A comparison of dollar losses shows that 1984 and 1985 were by far the costliest years since 1959. Comparison with a similar high-water period in the mid-1970s suggests that shorelines were much more vulnerable to storm damage in the mid-1980s when water levels were higher.     

Perspectives on U.S. Great Lakes Chemical Toxic Substances Research

Because of their magnitude, their geographic and demographic characteristics, and their unique limnological properties, the Great Lakes appear to be especially susceptible to chemical contamination. The scientific basis for dealing with this contamination is very limited compared with the magnitude of the problem. This is particularly evident when the vast array of toxic xenobiotic substances of anthropogenic origin are considered. Major knowledge gaps exist on the critical transport pathways, ultimate fate, and ecological effects of toxic substances (of urgent importance are health effects on humans residing in the basin), as well as on the economic and social aspects of toxics management.The economic climate of the 1980s, however, is likely to severely limit the resources available for the conduct of research which is so badly needed. Consequently, it appears that the Great Lakes research community will have imposed upon it a markedly increased demand for information and a concomitant reduction in the resources available to accomplish the task. Finally, despite a pessimistic outlook for research support, there is optimism that the Great Lakes will respond positively, and in a relatively short time span (years as opposed to centuries), to the abatement of toxic inputs. Nevertheless, additional information on the processes affecting the distribution and fate of toxic substances is still critical to the understanding required to ensure effective remedial actions.     

Characteristics of double-crested cormorant colonies in the U.S. Great Lakes island landscape

The Great Lakes form the largest freshwater island system in the world and provide breeding habitat for a large proportion of the continental population of double-crested cormorants (Phalacrocorax auritus). Here, cormorants have a high profile due to conflicts with humans; by 2007, most active (64%) breeding sites in U.S. waters were managed. This study used data from the U.S. Great Lakes Colonial Waterbird Database and The Nature Conservancy's Great Lakes Island GIS database to identify important features of breeding sites in the U.S. Great Lakes and broaden understanding of cormorant presence at the island-landscape scale. Islands 0.5–10 ha were used more frequently than expected, and most sites had remoteness values of ≤ 3 km. Colony size was positively correlated with years occupied and large colonies (> 1000 pairs) developed primarily (95%) on island sites > 1.0 ha. Sites supporting large colonies were more remote than those supporting smaller colonies. Presence of other colonial waterbird species, especially Herring Gulls (Larus argentatus), also characterized cormorant sites. Islands used by cormorants comprised a small proportion (n = 90, 3%) of the U.S. Great Lakes island resource, and < 1% of the total island area. Certain characteristics of breeding sites (e.g., small islands, proximity to mainland) may increase negative attitudes about cormorants. To understand cormorant impacts to island resources (e.g., vegetation; other colonial waterbird species), we suggest cormorant presence in the Great Lakes be considered in the broader context of island science, conservation and known threats, and at a landscape scale.     

Managing rivers under changing environmental and societal boundary conditions,Part 1: National trends and U.S. Army Corps of Engineers reservoirs

Most major rivers in the United States are managed by a system of reservoirs; many of which were built more than a half century ago. These reservoirs were designed based on environmental, societal, and regulatory assumptions at the time of construction. Since then, we have learned that climate is not stationary, population growth is being decoupled from energy needs and water demand, and new regulations (such as the Clean Water Act and Endangered Species Act) affect how river systems are managed. This study explores changing environmental, societal, and regulatory conditions relevant to the design and operation of U.S. Army Corps of Engineers reservoirs across the conterminous United States. Results demonstrate large geographic variability in how these conditions have changed over time. In the south‐western United States, there is an amplified trend towards drier conditions and less reservoir flexibility with warmer temperatures, less precipitation, high sedimentation rates, and large population growth. In the north‐eastern United States, the impacts of increased temperature on reservoirs may be masked by greater precipitation and lower water demand. Environmental, societal, and regulatory changes can reduce the flexibility of reservoir operations and, in some instances, make it challenging for the reservoir to meet its intended purpose as designed decades ago. This study is the first step towards formalizing a process for monitoring broad trends relevant to water resources management for the purpose of moving towards adaptation of infrastructure. An interactive tool was developed for each condition: https://nicholasinstitute.duke.edu/reservoir‐national‐trends/ .     

美国陆军工程兵团水电工程标准体系介绍

美国陆军工程兵团是世界最大的公共工程、设计和建筑管理机构,其水电工程标准体系在水电工程勘察、设计、施工等各方面研究、开发和应用上均处于世界领先水平,在世界范围的水电工程建设中得以广泛应用。了解其最新体系的情况,不仅对我国水电行业的发展有重要学习借鉴作用,同时对于中国企业实施“走出去”战略,融入国际经济合作也有重大的意义。     

Land Use Land Cover Change in the U.S. Great Lakes Basin 1992 to 2001

The pace of Land Use/Land Cover (LULC) change in the Great Lakes, particularly in urban and suburban areas, far exceeds that predicted by population growth alone. Thus, quantification of LULC and change through time may be a key factor in understanding the near-shore ecology of this system. The work described in this paper is part of a larger effort called the Great Lakes Environmental Indicators Project (GLEI), whose goal was to develop and refine environmental state indicators for the U.S. near-shore zone of the Great Lakes. Here we describe methodologies for using existing Landsatbased LULC maps to assemble consistent LULC data for the U.S. portion of the Great Lakes basin for 1992 and 2001, as well as summarizing salient LULC results. Between 1992 and 2001, 2.5% (798,755 ha) of the U.S. portion of the Great Lakes watershed experienced change. Transitions due to new construction included a 33.5% (158,858 ha) increase in low-intensity development and a 7.5% (140,240 ha) increase in road area. Agricultural and forest land each experienced ∼2.3% (259,244 ha and 322,463 ha, respectively) decrease in area. Despite the large and enduring agricultural losses observed (2.23% of 1992 agricultural area), the rate of agricultural land decrease between 1992 and 2001 was less than that reported by the EPA (−9.8%) for the previous ∼10-year period. Areas of new development were largely concentrated near coastal areas of the Great Lakes. Over 38% (6,014 ha) of wetland losses to development between 1992 and 2001 occurred within 10 km of a coastal area, and most of that area was within the nearest 1 kilometer. Clearly, these land use change data will be especially useful as quantifiable indicators of landscape change over time and aid in future land use planning decisions for protection of the integrity of the Great Lakes ecosystem.     

Managing rivers under changing environmental and societal boundary conditions,Part 2: Expected compared with experienced conditions at U.S. Army Corps of Engineers reservoirs

Reservoirs are critical infrastructure typically built to function as designed for 50 to 100 years. The majority of U.S. Army Corps of Engineers reservoirs are more than 50 years old. The environmental, societal, and regulatory conditions surrounding the reservoir, that is, the reservoir's expected conditions, shaped its design. Many of these expectations assumed a future similar to the past. However, recent decades have experienced warming climates, cyclical changes in precipitation, the introduction of new regulations, and populations concentrating in urban environments. The design documents for nine U.S. Army Corps of Engineers were obtained to compare the expected conditions when reservoirs were authorized with the conditions experienced since the reservoir began operating. In some instances, we found large differences between expectations and reality. Average precipitation at Philpott, North Carolina was 15% less than expected whereas the sedimentation rate at Redmond, Kansas was twice the expected rate. Reservoirs can adapt to changing conditions by updating water control plans, which has occurred at five of these reservoirs in the last decade. Reallocations are sometimes needed to address more significant changes. For example, Redmond has reallocated storage space due to higher than expected sedimentation, and Falls, North Carolina is seeking reallocation due to higher than expected population growth and water demand. As conditions change, controversies and litigation around Corps reservoir management will likely continue. This highlights the importance of clearly documenting changing conditions through consistent and ongoing data collection and analysis to facilitate adapting reservoir operations in a timely manner, thereby minimizing controversy.     

Winter limnology on the Great Lakes: The role of the U.S. Coast Guard

We describe a unique educational collaboration between the U.S. Coast Guard and Bowling Green State University with the goal of engaging Coast Guard crew members in a monitoring program intended to increase both temporal and spatial resolutions of sampling during winter in Lake Erie, a period where extreme weather conditions and safety considerations challenge our ability to sample.     

Drivers of revitalization in Great Lakes coastal communities

Sediment remediation and habitat restoration projects have been increasingly employed along the coast of the Great Lakes to improve environmental quality since the designation of 43 highly degraded Areas of Concern (AOCs) by the 1987 Great Lakes Water Quality Agreement between the U.S. and Canada. Improvements in water quality, habitat, and other environmental conditions can also support community wellbeing and revitalization; however, the mechanisms that support these connections are relatively unclear. We address this gap through a case study of three AOCs near Lake Michigan: 1) Grand Calumet River; 2) White Lake, and 3) Muskegon Lake. By analyzing secondary data and planning documents, we found that alongside environmental cleanup, anchor institutions, housing and economic development, and local events drive revitalization. Our research also illustrates that, rather than acting as discrete processes, environmental cleanup and revitalization drivers overlap in time and space. Finally, our research reveals a high level of variation within and across AOCs in terms of diverse socioeconomic contexts, planning capacities, and existing partnerships. Together, our findings point to the need for collaborative and inclusive planning processes that account for the heterogeneity present within and across AOCs to simultaneously support remediation, restoration, and revitalization and to sustain continued revitalization in AOC communities after delisting.     

Potential Impacts of Nesting Double-crested Cormorants on Great Blue Herons and Black-crowned Night-herons in the U.S. Great Lakes Region

With recovery of double-crested cormorants (Phalacrocorax auritus) in the Great Lakes region, their numbers have increased significantly leading to concern about potential impacts on other species. Cormorants are thought to affect co-occurring colonial waterbirds by usurping limited habitat and destroying vegetation used as nest sites by these species. This paper summarizes initial results from a study to assess potential impacts of double-crested cormorants on great blue herons (Ardea herodius) and black-crowned night-herons (Nycticorax nycticorax) in the Great Lakes. The study examined population trends, interspecific interactions, and cormorant impacts on vegetation. Despite a steady increase in breeding cormorants in the U.S. Great Lakes over the past two decades, population trends of great blue herons and black-crowned night-herons do not indicate cormorants have negatively influenced breeding distribution or productivity of either species at a regional scale. Cormorants have caused total or partial loss of forest cover at a number of islands in the U.S. Great Lakes and these initial data suggest soil chemistry at cormorant colony sites will affect normal plant growth and survival. However, site use data and field observations indicate double-crested cormorant presence has not caused black-crowned nightheron or great blue heron declines or abandonment except under special circumstances. Although preliminary, these results suggest cormorant control policy should not be justified by assumption of potential impacts on other waterbird species without careful documentation.     

Colonial waterbird site occupancy dynamics reflect variation in colony site environments in the U.S. Great Lakes

Colonies of breeding waterbirds are salient biological features of many of the world’s great lakes. Globally, status of colonial waterbird populations ranges from declining and in need of conservation to maintain their roles in aquatic ecosystems, to “overabundant” and managed to reduce human-wildlife conflict; both ends of this spectrum are observed in the North American Great Lakes. Conservation and management of colonial waterbirds should rely on knowledge of colony site use dynamics because the best approach may vary depending on the frequency with which historical colony sites are abandoned and new sites colonized. The goal of this study was to understand how site use dynamics are influenced by the physical and avian social environment, using the Great Lakes Colonial Waterbird Survey as a source of breeding-season site occupancy records. This study is the first to apply community occupancy modeling techniques to colonial waterbirds. Model parameter estimates were generated through a Bayesian analysis using Markov chain Monte Carlo simulation. Sites with large waterbird colonies and those not susceptible to flooding were most likely to persist as breeding locations into the next survey period, and thus should be prioritized for conservation and management. Additionally, the model demonstrated that co-nester presence was positively related to persistence probabilities, while relationships between colonization probabilities and co-nester presence ranged from positive to negative for different focal species. Finally, species-specific responses to presence of other species and to environmental influences were apparent; knowledge of this relationship variability should be incorporated into management strategies to achieve optimal outcomes.     

A brief history of the U.S. EPA Great Lakes National Program Office's water quality survey

The U.S. Environmental Protection Agency Great Lakes National Program Office (GLNPO) water quality survey (WQS) constitutes the longest-running, most extensive monitoring of water quality and the lower trophic level biota of the Laurentian Great Lakes, and has been instrumental in tracking shifts in nutrients and the lower food web over the past several decades. The initial impetus for regular monitoring of the Great Lakes was provided by the 1972 Great Lakes Water Quality Agreement (GLWQA) which asked the parties to develop monitoring and surveillance programs to ensure compliance with the goals of the agreement. The resulting monitoring plan, eventually known as the Great Lakes International Surveillance Plan (GLISP), envisioned a nine-year rotation of intensive surveys of the five lakes. A broadening of the scope of the GLWQA in 1978 and the completion of the first nine-year cycle of sampling, prompted reappraisals of the GLISP. During this pause, and using knowledge gained from GLISP, GLNPO initiated an annual WQS with the narrower focus of tracking water quality changes and plankton communities in the offshore waters of the lakes. Beginning in 1983 with lakes Erie, Huron, and Michigan, the WQS added Lake Ontario in 1986 and Lake Superior in 1992, evolving into its current form in which all five lakes are sampled twice a year. The WQS is unique in that all five lakes are sampled by one agency, using one vessel and one principal laboratory for each parameter group, and represents an invaluable resource for managing and understanding the Great Lakes.     

Environmental predictors of phytoplankton chlorophyll-a in Great Lakes coastal wetlands

Coastal wetlands of the Laurentian Great Lakes are diverse and productive ecosystems that provide many ecosystem services, but are threatened by anthropogenic factors, including nutrient input, land-use change, invasive species, and climate change. In this study, we examined one component of wetland ecosystem structure – phytoplankton biomass – using the proxy metric of water column chlorophyll-a measured in 514 coastal wetlands across all five Great Lakes as part of the Great Lakes Coastal Wetland Monitoring Program. Mean chlorophyll-a concentrations increased from north-to-south from Lake Superior to Lake Erie, but concentrations varied among sites within lakes. To predict chlorophyll-a concentrations, we developed two random forest models for each lake – one using variables that may directly relate to phytoplankton biomass (“proximate” variables; e.g., dissolved nutrients, temperature, pH) and another using variables with potentially indirect effects on phytoplankton growth (“distal” variables; e.g., land use, fetch). Proximate and distal variable models explained 16–43% and 19–48% of variation in chlorophyll-a, respectively, with models developed for lakes Erie and Michigan having the highest amount of explanatory power and models developed for lakes Ontario, Superior, and Huron having the lowest. Land-use variables were important distal predictors of chlorophyll-a concentrations across all lakes. We found multiple proximate predictors of chlorophyll-a, but there was little consistency among lakes, suggesting that, while chlorophyll-a may be broadly influenced by distal factors such as land use, individual lakes and wetlands have unique characteristics that affect chlorophyll-a concentrations. Our results highlight the importance of responsible land-use planning and watershed-level management for protecting coastal wetlands.     

Results from the U.S. Great Lakes Fish Monitoring Program and Effects of Lake Processes on Bioaccumulative Contaminant Concentrations

An analysis of composite samples of 820 lake trout, walleye, steelhead, Chinook, and coho from the Laurentian Great Lakes reveals differences in contaminant processing among and between lakes which results in differing concentrations of bioaccumulative contaminants. Generally, contaminants are most concentrated in fish from Lake Michigan and least concentrated in fish from Lake Superior, with the notable exceptions of toxaphene and alpha-HCH. Differences in contamination patterns, however, are apparent not only among the lakes but between sites within a lake or even fish within a site. Lake trout composites from Lake Superior show an increase in the degree of chlorination of PCBs with increasing total PCBs. The PCB congener profile of lake trout from the Sturgeon Bay site of Lake Michigan is substantially different from that of the Saugatuck site of Lake Michigan, possibly due to the influence of contamination from nearby Green Bay. Finally, the ratios of selected PBDE and PCB congeners are much different in Lake Superior fish compared to fishes from all the other lakes. We hypothesize that this is a result of the colder temperatures and associated lower plankton growth rates in Lake Superior allowing PCB and PBDE uptake by phytoplankton to reach near equilibrium, thus enhancing the relative concentrations, in phytoplankton and the food web in general, of congeners that may be kinetically limited in other lakes.     

美军野战供水系统介绍

饮用水供应是世界各国军队后勤保障的重要任务.美军的野战供水系统具备非常成熟的软件系统和硬件设施,简要介绍了美军的野战供水标准、供水方案和净水装置.     

Latitudinal gradient of floristic condition among Great Lakes coastal wetlands

Coastal wetland vegetation along the Great Lakes differs strongly with latitude, but most studies of Great Lakes wetland condition have attempted to exclude the effect of latitude to discern anthropogenic effects on condition. We developed an alternative approach that takes advantage of the strong relationship between latitude and coastal wetland floristic condition. Latitude was significantly correlated with 13 of 37 environmental variables tested, including growing degree days, agriculture, atmospheric deposition, nonpoint-source pollution, and soil texture, which suggests that latitude is a good proxy for several environmental drivers of vegetation. Using data from 64 wetlands along the U.S. coast of Lakes Huron, Michigan, Erie, and Ontario, we developed linear regressions between latitude and two measures of floristic condition, the Floristic Quality Index (FQI, adj. r² = 0.437, p < 0.001) and the first axis scores from a non-metric multidimensional scaling of wetland plant cover (MDS1, adj. r² = 0.501, p < 0.001). Departures from the central tendency of these regression models represented wetlands of better or worse condition than expected for their latitude. This approach provides a means to identify wetlands worthy of preservation, to establish vegetation targets for wetland restoration, and to forecast changes in floristic quality associated with future climate change.