FOR THE SAKE OF LAMPREY

Lamprey have remained largely unchanged for 360 million years, but today, their populations have been severely impacted by dams and habitat loss. For the past several years, Cascade Forest Conservancy has worked to incorporate lamprey habitat needs into restoration planning wherever lamprey may be present. 

 

 

Meet the Pacific lamprey: An Ancient Species at Risk

 

Adult Pacific lamprey have long, eel-like bodies and flexible, cartilage skeletons, and a number of unique features that set them apart from species that evolved more recently. Instead of gill slits, lamprey have rows of seven gill pores on each side of their heads. They have a single nostril (located on top of their head), lack paired fins, and perhaps most notably, adults possess disk-shaped and tooth-filled mouths they use to suction onto prey and even climb waterfalls as they travel upstream to spawn.     

 

Visitors to Bonneville Dam can see Pacific lamprey using their sucking mouths to navigate upstream to spawn. Lamprey have been on Earth for so long, they are older than trees!

Pacific lamprey are a culturally significant species for Indigenous communities and contribute to the health of aquatic ecosystems, but today, populations of these ancient survivors are in serious decline due to the impacts of impassable dams, predation by non-native fish, and habitat loss.       

Restoring aquatic habitat with lamprey in mind

 

Like salmon and steelhead, Pacific lamprey are anadromous, migrating as adults from saltwater to spawn in freshwater streams. They all share many habitat needs, including gravel-bottomed streambeds for spawning, access to side channels and off-channel habitats, and pools for refugia. However, while both species benefit from healthy, complex stream ecosystems, their habitat needs differ at certain stages of their life cycles.

Once Pacific lamprey hatch and develop into larvae, they depend on a very specific type of habitat for much of their lives. Larval lamprey move downstream and burrow into areas of fine sediment, where they can spend up to 10 years or more filter-feeding on algae, diatoms, and organic material, serving a key ecological role filter feeding beneath fine stream sediments.

 

Lamprey depend on a very specific type of habitat for much of their lives, typically found along stream margins, in pools, and in other slow-moving areas where fine sediments accumulate.

 

These habitats are typically found along stream margins, in pools, and in other slow-moving areas where fine sediments accumulate. In addition to fine sediments and organic material, larval lamprey also need adequate dissolved oxygen and suitable water velocities.

 

Although lamprey and salmonids share some habitat needs, stream restoration projects designed primarily to benefit salmonids often overlook the fine sediments critical to larval lamprey survival.

 

Because larval lamprey remain buried in sediment year-round, activities that disturb these areas can affect them at any time. Multiple age classes of lamprey may also occupy the same sediment patch, meaning a single disturbance can affect several generations.

Lamprey surveys at Salmon Creek

 

For the past several years, Cascade Forest Conservancy has worked to incorporate lamprey habitat needs into restoration planning wherever lamprey may be present. One example is our work on Salmon Creek, a tributary of the Cowlitz River. Previous observations of Pacific and Western lamprey throughout much of the watershed indicated that our restoration sites along the mainstem and tributaries could be providing habitat for lamprey.

The Pacific Lamprey Habitat Restoration Guide emphasizes the importance of understanding whether lamprey are present at a restoration site, which life stages use the habitat, and when and how they use it. With that guidance in mind, we conducted larval lamprey surveys across three project reaches of Salmon Creek in June and July before beginning restoration work. We used electrofishing and a modified sediment-sampling method developed by Lasne et al. (2010) to better understand where larval lamprey were present.

 

Several surveys have been conducted along Salmon Creek.

 

We found larval lamprey in two of the three surveyed reaches, with habitat and abundance changing substantially as we moved upstream. In just 10 minutes of electrofishing at one upstream sediment patch, we found approximately 30 larval lamprey! Based on the available habitat size, we estimated the area likely supported hundreds of larvae across different age classes.

These findings directly influenced our restoration plans. Because we found so many larval lamprey in the upper reach, we removed part of that area from our project design to avoid disturbing occupied sediment and potentially harming the population. 

Our work at Salmon Creek shows why surveying for lamprey before restoration matters. Projects designed to improve habitat for salmonids can also benefit lamprey, but without understanding where larvae are present, restoration activities can unintentionally disturb the habitat they depend on. By incorporating lamprey surveys into our planning, we can make more informed decisions that benefit a broader range of native fish species.

Thanks to Monica Blanchard at WDFW for electrofishing at our project sites, to the volunteers who dug around in the creek, and to the Pacific Lamprey Conservation Initiative for supporting the work to protect lamprey!

SIGNS OF TROUBLE AND HOPE AT MCDONALD RIDGE

Cascade Forest Conservancy staff, volunteers, and Forest Service botanists recently conducted native plant surveys in wildfire-impacted forests beneath the slopes of Mount Adams. 

There we observed signs of climate change impacts affecting our forests, but documented examples of how CFC and our community can make a positive impact.  

 

This location, McDonald Ridge, has experienced four wildfires in 16 years. CFC and the US Forest Service are partners in a yearslong effort to support the recovery of native plant communities on the landscape and improve habitat for pollinators at this high elevation site.

 

On this occasion, we climbed the ridge to visit a site planted and seeded in April of this year during an unusually timed spring planting trip that was only possible due to low winter snow pack.

 

 

Among charred trees and fallen logs, we found that many individual native flowers and shrubs we seeded and planted in the past were surviving and growing. We also saw other species of native plants recovering on their own, plentiful blooms, and many busy pollinators.

Climate change in our region is increasing the frequency and severity of droughts and wildfires, and current conditions in the Pacific Northwest could make the 2026 wildfire season one of the worst in years.

But as we recently observed on McDonald Ridge, community and partnership-driven restoration efforts are also having an impact.   

PROJECT UPDATE: INVASIVE SURVEYS IN TIMBER UNITS

Parts of the Gifford Pinchot National Forest and other national forests possess something increasingly rare in the western United States: forests and river corridors largely free of invasive plants. These places are important refuges for native plant communities, including many rare and threatened species. 

This is not something we should take for granted. As collaborators in the stewardship of this area, we feel a great sense of responsibility in doing what we can to help keep it this way. 

More and more, we are seeing formerly healthy native plant communities in the national forest succumb to aggressive invasive species like scotch broom, herb Robert, bull thistle, and others. Cascade Forest Conservancy, often with the help of our science and stewardship volunteers, have worked throughout the years to remove invasive species from sensitive habitats and conduct field mapping to record new outbreaks of invasive plants to share with partners and work collaboratively to keep further expansion at bay.

 

 

These efforts are important, but the best way to protect our local native ecosystems is to prevent outbreaks of invasive plant species before they happen.

Roads are known pathways for these introductions, but an under-discussed and increasingly impactful vector for invasive species are the logging machines that wind their way into previously intact forest stands. Too often, this results in outbreaks of invasive plant infestations that will be in these areas for perpetuity.

Cascade Forest Conservancy is working to address this threat on multiple fronts. 

In our role as watchdogs, we study and weigh in on the Forest Service’s plans for all timber sales and other management actions. We find that the introduction of invasive plants is often mentioned only in passing in Forest Service planning documents. While there are mitigation measures written into timber planning documents, such as stated requirements for equipment to be cleaned and checked for weed seeds, these protocols are insufficient to combat the scale of the problem or the seriousness of the threat to rare strongholds of local biodiversity.

Today, due to increased timber targets forced on land managers and a renewed rush to access new forest stands for logging, the integrity of native plant communities are at risk.

 

 

We continue to highlight these risks in formal comments on timber sales and in our conversations with Forest Service planners. More recently, we’ve launched an additional new effort to monitor recently logged forests for early signs of invasive plant establishment.

By detecting and treating infestations early, we aim to reduce long-term impacts and help protect these vulnerable ecosystems. We can sometimes treat these areas on the spot through hand-pulling; other times we share our findings with the Forest Service and the county weed treatment teams for more comprehensive treatment and, hopefully, continual monitoring. While this effort won’t stop all new infestations, it’s a meaningful step we can take, and one that we’re pursuing through volunteer trips that bring community members directly into these forests to assist with invasive plant surveys and control.

We continue to highlight these risks in formal comments on timber sales and in our conversations with Forest Service planners. More recently, we’ve launched an additional new effort to monitor recently logged forests for early signs of invasive plant establishment.

By detecting and treating infestations early, we aim to reduce long-term impacts and help protect these vulnerable ecosystems. We can sometimes treat these areas on the spot through hand-pulling; other times we share our findings with the Forest Service and the county weed treatment teams for more comprehensive treatment and, hopefully, continual monitoring. While this effort won’t stop all new infestations, it’s a meaningful step we can take, and one that we’re pursuing through volunteer trips that bring community members directly into these forests to assist with invasive plant surveys and control.

Timber harvest and wildfires

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