When we think about restoration, many of us imagine returning a habitat or landscape to a specific picture in our mind. A flowery meadow full of deer or an open water wetland fringed with vegetation and filled with birds and amphibians alike. But habitats change. Trees creep into the meadow and cattails or invasive grasses fill in ponds.
Some habitat types are the result of disturbance regimes, meaning they require frequent disturbance to be maintained. These disturbances come in many forms – fire, flooding, landslides, human activity, or even wildlife.
Oak woodlands and prairie habitats are prime examples. These ecosystems primarily rely on disturbances from humans and natural fires. Similarly, certain wetland conditions are a result of zoogenic, or animal-driven disturbance. Beavers (Castor canadensis), for instance, play a critical role in creating desirable wetland conditions for many species. As they build dams, they create log jams and move woody materials across the landscape, producing a mix of still and flowing water, shallow and deep areas, which support a wide range of wildlife.
Many species rely on these disturbed habitats. Without regular disturbance, oak woodlands and prairies can become overgrown with introduced plants and conifers. These changes can lead to the loss of habitats preferred by species such as waterfowl, forest birds, and amphibians.
All habitats change over time, but not all in the same way or at the same speed. Despite this, we need to plan for eventual changes when restoring habitat. This concept is at the heart of a new project led by Ducks Unlimited in the Willapa and Chehalis areas of Western Washington.
By adopting an approach to conservation that embraces anthropogenic-driven and natural change, projects can create more diverse environments supporting a wide range of species, ultimately leading to more effective conservation efforts.
The Project
Ducks Unlimited, Washington Department of Fish and Wildlife, Chehalis Basin Land Trust, Kaleidoscope Foundation, and Laidlaw Island Hunt Club came together to develop a large-scale project in the Willapa-Chehalis region to conserve priority wetlands and bird habitats.
Funded this year by a North American Conservation Wetlands Act (NAWCA) grant, the project encompasses 10 different sites around the region, benefitting a host of birds, fish, and amphibians. The project will conserve 1,672 acres of freshwater wetlands, estuarine tidelands, working agricultural lands, oak woodland, and temperate rainforests. These habitats support waterfowl, shorebirds, and other wildlife such as Marbled Murrelet (Brachyramphus marmoratus), Green Sturgeon (Acipenser medirostris), and Pacific Salmon (Oncorhynchus spp.), species that require different habitats at different points in their life cycle.
By adopting an approach to conservation that embraces anthropogenic-driven and natural change, projects can create more diverse environments supporting a wide range of species, ultimately leading to more effective conservation efforts.
One specific site from this project illustrates this approach clearly. The site includes agricultural and pasture lands, oak woodlands, wetland remnants, and a population of federally threatened Oregon Spotted Frogs (Rana pretiosa). C.K. Eidem, a Regional Biologist at Ducks Unlimited and Project Officer, Tract Manager, and Conceptual Design lead, shared insights on the multi-species, multi-habitat conservation strategy they have planned for this site, and how it will benefit both frogs and birds.
Wetland Restoration
The wetland component of this project focuses on habitat improvements that will benefit the Oregon Spotted Frog as well as target waterfowl species such as Northern Pintail (Anas acuta), Wood duck (Aix sponsa), and Pacific Greater White-fronted Goose (Anser albifrons frontalis). Because these species have complementary habitat needs, restoring wetland conditions will help multiple species at once.
The Oregon Spotted Frog, in particular, has very specific habitat requirements and breeds communally in shallow pools with high sun exposure and short vegetation. Thus, they need shallow wetland habitats with short vegetation, as well as still and moving water systems in proximity. These are also key needs for waterfowl that rely heavily on these habitats for foraging, resting, and nesting.
Beavers have a long and complex history in the Pacific Northwest. In the 1800s, native Beaver populations plummeted due to unregulated and unsustainable trapping, nearly going extinct in the region. However, with improved protections and management, they have now reestablished in many of their former habitats and expanded beyond.
They are best known for their dams – massive, complex structures that effectively block water flow creating areas of deeper, slow-moving water. These ecosystem changes benefit many species including waterfowl, amphibians, and salmon. And given enough space, Beavers can create habitat conditions required by Spotted Frogs.
Reduced Beaver presence at the Willapa-Chehalis project site has contributed to a decline in suitable habitats and breeding grounds for waterfowl and Spotted Frogs. Taking a page out of the Beavers’ book, C.K. shared that, “Where we can, our projects use Beavers or mimic their dams and ponds to create wetland habitat.” These “Beaver dam analogs”, or man-made log jams, help conservation managers mimic the ecological benefits of Beavers, establishing wetland habitats with variations in water depth and flow.
Outside of Beaver declines, Spotted Frogs face additional threats including invasive species like reed canary grass, which threaten to overtake breeding pools and shallow wetlands. Predation by game fish, Bullfrogs (Lithobates catesbeianus), Great Blue Herons (Ardea herodias), and Mink (Neogale vison) also pose significant threats to Spotted Frogs.
To address these challenges, a key part of this project involves “de-leveling” pasture lands to better control surface water flow, creating more favorable habitats for both Spotted Frogs and waterfowl. Partners will also construct shallow ponds to serve as Spotted Frog breeding sites and connect old pasture water sources to form larger, sustainable wetlands. Native trees and scrub-shrub vegetation will be planted to further improve ecosystem functions.
The project will require ongoing efforts to maintain these conditions. Managers will either mow or bring in livestock to graze the wetlands, keeping vegetation short and helping to control the growth of reed canary grass. The wetlands also need to remain shallow enough to dry out or be periodically drained, to ensure they can bring in necessary equipment for these activities, adding a layer of complexity to the work.
Oak and Prairie Habitat Restoration
Oak and prairie habitats, once abundant across the Pacific Northwest, also require active management to thrive. Oaks evolved in areas with frequent, low-intensity fires, which help slow conifer encroachment, clear the understory, and promote oak sprouting. Native Americans also contributed to thriving oak and prairie habitats through cultural and traditional burning practices and oak stewardship. Today, oak declines are largely due to fire suppression, conifer encroachment, timber conversion, cattle grazing, and urban development.
At the same project site, oak woodlands will be actively managed by thinning the oak forest to promote healthy oaks and removing conifers and unhealthy trees. The understory will also be cleared and native grasses and vegetation will be planted, to improve the area’s resilience to fire and encourage oak growth.
Multi-species Impact
Ongoing management is needed in wetland and oak and prairie systems to maintain the benefits of these restored habitats. At this site alone, restoration will have a positive impact on a wide variety of species. Waterfowl species such as American Wigeon (Mareca americana), Cackling Goose (Branta hutchinsii), Bufflehead (Bucephala albeola), Common Merganser (Mergus merganser), and Green-winged Teal (Anas carolinensis) will thrive. Other bird species like the Western Screech Owl (Megascops kennicottii), Olive-sided Flycatcher (Contopus cooperi), and Northern Harrier (Circus hudsonius) will also benefit from the restored oak woodlands, wetlands, and surrounding forested areas. And of course, these habitat improvements will support the recovery of the threatened Oregon Spotted Frog.
