Objective: Provide planners and coastal restoration practitioners with tools, resources, and on-the-ground examples to aid in planning, prioritizing, and executing habitat restoration projects that consider both climate change impacts—so that project investments are more enduring in the face of changing conditions—as well as how conservation action can contribute to coastal resilience for surrounding human communities.
Authors: Katherine Kahl, The Nature Conservancy, Rachael Franks Taylor, formerly The Nature Conservancy, & Tara Baranowski, The Nature Conservancy
Publication Date: January 20, 2014
Revision Date: April, 2016
Update Note: Major components of this Case Study project have been completed. Please scroll down to the end of this study for an update summary and links to current detailed information.
Among its many significant benefits, Lake Erie provides drinking water for 11 million people, is a well-known bird migration corridor, contributes over nine billion dollars annually to the region's economy from tourism and sport fishing alone, and produces more fish suitable for human consumption than all the other Great Lakes combined. The majority of that biological productivity–and human population–occurs in and around the western Lake Erie basin. Yet as much as Lake Erie is celebrated, it is highlighted as an example of ecological decline. Harmful algal blooms and nuisance algae are a recurring problem, and include a massive bloom in 2011 followed by a reprieve in 2012 when drought conditions led to less runoff from the largely agricultural watershed (see Figure 1). This is just one notable example of alteration to the Lake Erie environment over the past 200 years. While extensive and species-rich wetlands continue to provide great cultural value and key ecosystem services on which people rely, these wetlands and the shorelines of western Lake Erie have been extensively altered or lost due to development, conversion, drainage, and modified hydrology and sedimentation patterns (Figure 1). Only five percent of the estimated original 307,000 acres of Lake Erie wetlands remain, and these losses continue. In the recently released Lake Erie Biodiversity Conservation Strategy (Pearsall et al., 2012), the lake's coastal wetlands were assessed as "fair"–meaning that they will not be viable without conservation action. Thoughtful restoration that considers habitat function as well as current and future threats such as climate change is critically needed to ensure that the remaining biota can persist and be resilient over time.
In addition to significant wetland alterations and losses, agricultural runoff in the form of sediment and nutrient loading threatens coastal health. These stressors are likely to increase as a result of climate change, as both current trends and future projections strongly suggest that the peak intensity of storm events will increase in this region (Titus et al. 2009, Pryor et al. 2009). Besides improving habitat quality, restoration projects can address these stresses and restore wetlands' ability to attenuate sediments and nutrients, convert former agricultural lands back to natural habitat, and/or provide enhancements on lands still in agricultural production, allowing some of the lost ecosystem services to be regained while still providing economic opportunities.
The purpose of this case study is to provide planners and coastal restoration practitioners with tools, resources, and on-the-ground examples to aid in planning, prioritizing, and executing habitat restoration projects that consider both climate change impacts—so that project investments are more enduring in the face of changing conditions—as well as how conservation action can contribute to coastal resilience for surrounding human communities.
To demonstrate how these resources and considerations have been put into practice, the ongoing restoration of 585 acres of coastal habitat in the Ottawa National Wildlife Refuge will be used as an example in this case study. To complete this restoration The Nature Conservancy has partnered with the U.S. Fish and Wildlife Service, Ducks Unlimited, and NOAA to:
- restore altered hydrology and plant native vegetation on former agricultural lands,
- engineer a water conveyance system, and
- construct a gated structure and fish ladder along the Toussaint River, providing fish passage between a newly restored 100-acre wetland and western Lake Erie.
Coastal habitats are dynamic. Restoring the health and function of these habitats means rehabilitating some of the processes on which they rely.
Wetland Habitat: Ottawa National Wildlife Refuge
Courtesy of U.S. Fish and Wildlife Service
- Water Filtration: Wetlands are like the kidneys of the landscape, helping to filter out sediment and pollutants and improving water quality.
- Flood Control: In addition to benefiting water quality, coastal wetlands help moderate water quantity, helping to absorb and store water from precipitation events and preventing or minimizing flooding of surrounding areas.
- Diverse, Native, Climate-Adaptable Species: Native plant species are essential to ecological function. These species are often specialized to local conditions and serve specific niches. Depending on the nature of the restoration site, native species may have been lost or suppressed, requiring replanting. In cases where invasive species have flourished, those invaders will need to be controlled to a degree that – and select species accordingly.
B. How Can Restorations Make Communities More Resilient?
Functional coastal wetlands provide a number of ecosystem services, such as flood control, attenuation of sediments and nutrients, erosion prevention, improvement of water quality, and habitat (Maynard and Wilcox, 1997). Shoreline systems are dynamic environments and are subject to forces from both the land and adjacent waters. Climate change can amplify these dynamic conditions through more frequent storms and the increased wind and waves that result, more extreme lake level fluctuations, and altered precipitation patterns and temperature regimes. Restoration can help improve the services that coastal wetlands provide as well as their resilience to changing conditions.
- Lake Level Fluctuation: Many of the remaining coastal wetlands have been disconnected from Lake Erie and are no longer subject to natural, periodic lake level fluctuations. (Note that some diked wetlands have water conveyance systems that emulate lake level changes.) Inundation helps control invasive species like Phragmites, while the exposure of mudflats and bottom sediments helps stimulate growth of native plants from the seed bank. Considering ways to restore this hydrologic regime between the target wetlands and Lake Erie is a key consideration for enduring restoration benefits.
- Connectivity: In addition to the hydrologic regime, connectivity to Lake Erie also restores the exchange of nutrients and aquatic species between wetlands and the lake. Coastal wetlands provide key energy and nutrients that form the basis for the nearshore and open water food webs as well as fish spawning and nursery habitats, services that are lost when wetlands are disconnected.
- Shoreline Stabilization and Erosion Prevention: Functional coastal wetlands offer protection to upland habitats and properties by serving as a buffer against daily erosive forces (wind, waves, ice) and more extreme events (storm surge, seiche). Heavily engineered stabilization structures can disrupt coastal processes that determine where coastal wetlands will form and persist and have the potential to create additional problems elsewhere. Their potential impacts on coastal wetlands include, but are not limited to, the creation of barriers that prevent in-lake aquatic species from accessing wetland habitats and preventing coastal wetlands from migrating with lake level fluctuations.
- Fish and Wildlife Habitat: Coastal wetlands also provide critical habitat for a wide variety of fish and wildlife species, migratory birds in particular. The presence of these migratory species is a huge draw for birdwatchers throughout the region, who contribute an estimated $30 million in recreation and tourism revenue to the economies of coastal communities along Lake Erie alone (Xie, 2012).
Diagram of Wetland Values
Courtesy of Green Planet Ethics
This section outlines some of the analytical resources available to aid in selecting a restoration site and designing a site-specific restoration project. Not all resources were used in the project described in this case study due to their availability at the time of project inception (many are new or under development), the early selection of the site based on partner needs and project benefits, and the project's focus on habitat resilience—including enduring benefits under projected climate changes—rather than on coastal hazard mitigation.
Selecting a Restoration Site
Western Lake Erie Restorable Wetlands Assessment (TNC): The Nature Conservancy (TNC) and NOAA, working under a national partnership, collaborated with the University of Michigan-Dearborn and U.S. Geological Survey to develop a Restorable Wetlands Assessment, which can help funders and practitioners identify some of the most regionally or locally restorable areas. This assessment focuses on hydrologic reconnection, while recognizing that other enhancements may be necessary. By mapping remaining coastal wetlands as well as diked and drained wetlands, the assessment also provides a foundation for examining the ecosystem services and functions those wetlands currently or could potentially provide if restored. This assessment draws on a number of data sources and tools that are available for the Great Lakes region, including Great Lakes Coastal LiDAR data (NOAA Digital Coast) and the Oblique Photo Viewer (U.S. Army Corps of Engineers).
Oblique Photograph of Ottawa NWR
Taken from U.S. Army Corps of Engineers Oblique Photo Viewer
Considerations for Restoration Design
Once a site has been selected for restoration, some factors to consider include: what types of species to reintroduce (if necessary), analyzing the hydrogeomorphic processes that need to be accounted for during the restoration, and what type of passive or active connectivity structure meets project goals. During the design phase it is also important to consider a range of current and future conditions.
Climate‐Smart Restoration and Great Lakes Coastal Future: Tools for the Design and Implementation of 'Guide to Climate Change Vulnerability Assessment' (National Wildlife Federation): Staff from NOAA and the National Wildlife Federation helped the project manager assess climate change impacts and how future conditions might influence anticipated benefits of the project, leading to recommendations about appropriate tree species that were both native and likely to withstand future climate conditions for the aspects of the project involving revegetation of former agricultural lands.
Climate Wizard from The Nature Conservancy
Climate Wizard (The Nature Conservancy): Climate Wizard and its Custom Analysis tool for user-defined geographies and analyses allows practitioners to examine the restoration site under a range of future climate conditions. Users can by region visualize historic and potential future temperature ranges and precipitation fluctuation over time in order to understand and appropriately design projects that account for these parameters.
Great Lakes Water Level Dashboard (NOAA Great Lakes Environmental Research Laboratory): The Great Lakes Water Level Dashboard provides an interactive viewer with which to explore historic and future projections of water levels for the Great Lakes. Restoring coastal wetland hydrology can be active (using water conveyance systems) or passive (reopening habitats to the lake), and the approach can be informed by analyzing existing restrictions to flow or the movement of aquatic species. In these cases, a fish passage or connectivity structure can be sited with consideration for current and likely future placement relative to lake levels.
Great Lakes Lake Level View (NOAA Office for Coastal Management): The NOAA Lake Level Viewer is a useful communitications tool that allows users to visualize where inundation would occur if water levels in the great lakes were to increase by 6 feet and how the coastline would change if water levels declined by 6 feet.
NOAA Lake Level Viewer
Taken from: NOAA Lake Level Viewer
The strategy for this project involved a series of restoration activities undertaken on five separate tracts (see Figure 2) within the Ottawa National Wildlife Refuge, totaling 585 acres of restored habitat.
Figure 2. Project Overview
Courtesy of The Nature Conservancy
The specific objectives for which this project was undertaken include (Please note: tract-by-tract descritpions pictured below):
- Restoration of 100 acres of new emergent, herbaceous wetlands See Blausey tract description...
- Restoration of 83 acres of forested uplands and wetlands See Helle and MS#2 tract descriptions...
- Restoration of 33 acres of grasslands and sedge meadow See Kontz tract description...
- Creation of 170 acres of new fish habitat See Blausey and Pool 2a tract descriptions...
- Enhancement of 296 acres of fish and wildlife habitat See Blausey, Helle, Kontz, and MS#2 tract descriptions...
- Reduced sediments and nutrients entering the Toussaint River, thus improved quality of waters entering southwestern Lake Erie
- Increased food supply and cover for migrating and breeding birds
- Reestablishment of hydrologic and biologic connectivity in a priority coastal tributary
- Increased habitat for wetland-dependent fish and wildlife species, including many federal and state threatened and endangered species
- Increased spawning and nursery habitat for over 25 species of fish, including walleye, yellow perch, northern pike, largemouth bass, and crappie species
- Improvement in Index of Biological Integrity scores for fish community species
- Increased populations of sentinel and focal bird and other animal species. Sentinel species for the Maumee Area of Concern include bald eagle, great blue heron, and mink, while wood thrush, dunlin, and blue-winged teal may comprise focal taxa. Sentinel species are species that are used as indicators of a given ecosystem's health, as their presence or absence denotes the existence of specific conditions in a habitat, community, or that ecosystem. Focal species refers to a species of biotic organism that holds some kind of cultural or ecological significance within a region. In the western Lake Erie region both focal and sentinel species are priorities for ecosystems management (Zacharias & Roff, 2001).
- Enhanced resiliency to climate change vulnerabilities through improved water conveyance and water level control to restored wetlands, and
- Contribution to the delisting of Beneficial Use Impairments (BUIs) in the Maumee Area of Concern, which included degradation of fish and wildlife populations, degradation of benthos, and loss of fish and wildlife habitat.
Although climate change will stress the western Lake Erie coastal system through increases in temperature, changes in precipitation regime, and potential changes in lake level regime, the desired restoration outcomes described above are all likely to help increase resilience. Our work increases habitat availability in an area where there have been major losses and improves connectivity at both local and continental scales (e.g. through providing more stopover habitat for birds). Further, while in an ideal restoration situation we would not need to manage water levels through mechanical means over the long term, the fact that this project incorporates water control does reduce the risk that any changes in precipitation or lake levels that occur will undermine our ability to reach our conservation goals.
Ottawa National Wildlife Refuge Project Update
The Nature Conservancy (TNC), Ducks Unlimited, and U.S. Fish and Wildlife Service collaborated on this project. Funding was provided by NOAA with a $1,306.520 grant through the Great Lakes Restoration Initiative. Matching work was provided by TNC through unrecovered indirect costs and contractual expenses for invasive plant treatment. The majority of the grant award was sub-contracted to Ducks Unlimited for project engineering and construction management. The entire project will enhance 512 acres of coastal wetland and associated upland through a combination of native reseeding, reforestation, contouring, invasive plant removal, and installation of water control structures.
The project extended from July 2011 through June 2014. Construction began soon after funds were awarded in late 2011, and enhancements in the Blausey Tract were complete by the early months of 2013. In 2013, 82% of birds observed during breeding season surveys were waterfowl and shorebirds, such as great egrets, great blue heron, pied-billed grebe, and solitary sandpipers. Additionally, hundreds of waterfowl and shorebirds were observed utilizing the unit during migration season. Prior to the restoration, only 4% of the birds observed were waterfowl or shorebirds. Restoration provided a remarkable increase wetland birds in a short time.
In addition to the 171-acre Blausey restoration, this project included work at four other locations. Restoration work planned for all tracts has been completed.
For recent detailed information regarding this project see the following links:
Ohio's Country Journal, "Wetland Rehabilitation Effort Paying Off"
The Nature Conservancy Case Studies: Ottawa National Wildlife Refuge