Oregon Spotted Frog Needs Local Help

Under ideal growing conditions in restored habitat, Oregon spotted frog tadpoles may grow as large as this individual before completing its trans- formation into a frog. (August 2, 2020.)

by Lorraine Wilde

Endemic to the Pacific Northwest and historically distributed in the Puget Trough/Willamette Valley province and the Cascade Mountains of south-central Washington and Oregon, the Oregon spotted frog (OSF) has been lost from more than 78 percent of its original range, in estimations (1). The frog was first listed in 2004 on the International Union of the Conservation of Nature’s Red List of Threatened Species (2) and later listed as Endangered in Canada under the Species at Risk Act in 2013, then as Threatened under the Endangered Species Act in the United States in 2014. 

Its decline has been linked to the presence of the invasive bullfrog and reed canary grass, as well as loss and degradation of breeding habitat due to human impacts like dam construction, alteration of drainage, urban and agricultural use of water, and other activities that reduce or eliminate the still, shallow freshwater habitat on which they rely (1).

Whatcom County is home to some of the few remaining populations in Washington state, and local scientists have been working hard for almost a decade to help this delicate species not only survive but hopefully thrive and recover despite a shifting climate and development pressures. Community partnerships may be the key to their recovery. Local scientists have been partnering with local, regional and state agencies, citizen scientists, private land owners and nonprofits like Whatcom Land Trust to monitor OSF populations and conduct studies that will determine how best to approach their restoration and recovery.

Private Land Ownership Hampers Effort
“For a long time, the only known populations surviving in Washington were in Thurston and Klickitat County,” explains lead amphibian scientist Dr. Stephen Nyman of the Whatcom County Amphibian Monitoring Program (WCAMP). “There are historical records of Oregon spotted frog in the Lower Skagit River, in the Snohomish and in Lake Washington, but those are all extirpated. In Oregon, they used to be in the Willamette Valley, but are now extirpated there too. They still exist in a bunch of sites in the Oregon Cascades like the Deschutes and the Klamath. Originally they extended into Northeast California, but as far as we know they are extirpated there. We’re almost certain that they were never widespread and they were probably discontinuously distributed.”  

According to Nyman, the species was first found in Whatcom County in 2011 — before the species was listed. “From 2011 through 2013, the WDFW [Washington Department of Fish and Wildlife] and the U.S. Fish and Wildlife Service joined together and did a bunch of surveys and got permission from a lot of land owners,” remembers Nyman. “Back then it was established that there are three drainages where surveys tell us the frogs are present — the Upper Samish, tributaries in the lower South Fork Nooksack River, and one site in the Sumas River drainage.” 

But initial surveying efforts faced hurdles posed by private land ownership. “WDFW really made a big effort and some of those landowners got spooked, especially when they heard it was going to get listed, and, since it got listed, we haven’t had access because the landowners thought it would be a terrible thing if they had this listed species on their property,” remembers Nyman. “Even though the WDFW and Fish and Wildlife aren’t going to tell them what to do on their property — they can’t really — people have this attitude that it’s my land and I can do what I want and I don’t want you here, even if there are frogs here, we don’t want you to come back and look for them anymore. It’s a hugely frustrating thing.”

This phenomenon continues to hinder our collective understanding of the species, especially in areas where populations are most isolated. “In the Sumas River drainage, there is only one site where the frogs were found in 2011 or 2012. They haven’t been surveyed since at all so we just have no clue what’s happening with the populations there,” explains Nyman. “There are some places where no one’s ever done a survey because you can’t get cooperation from the landowner. So, there are probably populations in the watersheds where we know they would occur but we just can’t confirm that there are frogs there and we also can’t do anything to enhance the habitats because no one has permission.”  

Covid-19 has also made it extra difficult in the past two years for scientists and volunteers to go door to door or do group surveys.

Oregon spotted frog tadpoles require 90-130 days to achieve metamorphosis. In our area, habitat must hold water until July or August for tadpoles to succeed. (July 13, 2019.)
photo: Stephen Nyman

Since 2012, new populations have been discovered in the tributaries of the South Fork Nooksack River. “Originally they were found on one tributary called Black Slough, which was recently obtained by Whatcom Land Trust,” notes Nyman. “Eventually they were found on multiple tributaries including another Land Trust property — Catalyst Preserve. Two years ago, we found them on another Land Trust property upstream of Catalyst.” The 236-acre Catalyst Preserve contains several tributaries of the South Fork.

The Whatcom Land Trust recently worked with landowners to facilitate Whatcom County’s purchase of the Black Slough property this past December. “The Trust acted as a liaison between the county and the landowner, and the county purchased the property in order to allow for restoration of the wetlands and stream bank,” explains Whatcom Land Trust Conservation Manager Alex Jeffers. “The Trust, Whatcom County, South Fork residents, the Nooksack Indian Tribe and others are partnering on a long-term vision to restore the Black Slough and surrounding wetlands to support a variety of wildlife — including the OSF — that once thrived in this part of the valley. Additionally, the restoration will help increase late-summer stream flow and improve water quality in the South Fork Nooksack River Watershed.”

Local Scientists Lead the Way
Wetland ecologist and WCAMP’s Program Manager Vikki Jackson established the all-volunteer organization in 2011, before OSF was even on their radar. Nyman got involved a couple years later. “I got involved when I heard Oregon spotted frogs were discovered up here. In 2014, I started a little research project and then the species got listed at the end of that year,” remembers Nyman. “After that, I got a permit from U.S. Fish and Wildlife to work with the species and then applied for a $26,000 grant to do a before-and-after restoration study — to see how the population responded to restoration efforts.” 

WCAMP is able to receive grants and donations under the umbrella of the nonprofit, the Wildlife Conservation Trust. Nyman has thus far been successful in earning three small grants for Oregon spotted frog monitoring and restoration — the first for $26,000, a second for $25,000 and a third for $35,000. Jackson and Nyman were also recognized for their efforts in 2020 among the U.S. Fish and Wildlife’s Threatened and Endangered Species Recovery Champions.

“This work is heavily dependent on volunteers,” explains Nyman. “More than 55 percent of the work time is donated, including a lot of my own. Most of the funds go toward materials and equipment like native plants and a brush cutter.” Nyman’s second grant, which ended at the end of 2021, employed some new habitat restoration techniques to determine their effectiveness in helping OSF populations recover.

“What a lot of people do annually to help the Oregon spotted frog is that they either mow or use grazing to create areas where vegetation is either cut down or grazed very low, because Oregon spotted frog need openings in emerging herbaceous wetland vegetation for their breeding sites,” explains Nyman. “Because we have invasive reed canary grass at all of our sites that grows to be about seven feet tall, we don’t have any openings at all and we basically have no breeding habitat, just unmanaged reed canary grass, including at the Samish River Preserve.”

In 2008, Whatcom Land Trust purchased 65 acres in the headwaters of the Samish River near Wickersham that eventually became Samish River Preserve. Alpine Meadows Tree Farm owners, brothers Ken and Lewis Stremler, sold the property — once part of the historic Judson homestead built in 1888 — for 30 percent less than the appraised fair market value. 

“Prior to the Whatcom Land Trust buying the property, the preserve was mowed for hay and previous landowners had cows that were grazing down the invasive grass,” remembers Nyman. “When the property was added to the Trust, the grazing stopped and the habitat became less and less suitable for the breeding frogs. So, we had to do something. Instead of just mowing, we needed to actually change the vegetation and restore native plants.”

But, habitat restoration for the OSF at the preserve presented a number of challenges. “The Samish River Preserve is really interesting,” notes Nyman. “It’s essentially a thick floating mat of reed canary grass in relatively deep water. If you take out the invasive reed canary grass mat, all of a sudden you’ve got water for tadpoles and, in some cases, that water doesn’t dry out all year. Although 2021 was one of the drier years, some of those pools didn’t dry out. We saw that just by taking out the reed canary grass, it created an opening for these other plant species. There were apparently enough seeds in the soil or brought in by ducks for a dozen native plant species to re-establish in these habitats.” 

Based on that success, their third and most recent grant enabled WCAMP to plant desirable wetland species at Whatcom Land Trust’s Catalyst Preserve. Reed canary grass was removed and then fast spreading native plant species like the common spike rush and several species of sedge were seeded in coconut fiber coir mats that act to suppress the reed canary grass from resprouting. 

“Once established and really dense, these mats are competitive at least in the short term. We don’t yet know whether they’ll last 10 years or 15 years or … we just don’t know, but it was very cost effective in the short term and it does seem to have been effective,” notes Nyman. “Part of what we’re trying to determine is, what are the best species to re-establish? Once you get these species going, they produce a lot of seed and there’s no stopping them. That’s all very encouraging.” 

In 2021, the Whatcom County Amphibian Monitoring Program created a new pool (in foreground) and expanded others by removing reed canary- grass, which occurs here as a floating mat. (October 7, 2021.)
photo: Stephen Nyman

WCAMP’s approach focuses on continually building on previous successes. “Every year we’re trying to eliminate reed canary grass in a core area and make that bigger and bigger while also connecting different pools so that the Oregon spotted frog tadpoles can move from pool to pool as the water dries,” notes Nyman. “Connectivity is really important. The frogs can hop between sites, but obviously the tadpoles have to have aquatic connections between habitats.”

Another Challenge: Invasive Bullfrogs
Reed canary grass isn’t the only invasive species threatening the survival of the OSF. The American bullfrog (Lithobates catesbeianus), the largest of all North American frogs, can grow to a length of eight inches or more and weigh up to 1.5 pounds. That’s vastly bigger than the OSF, measuring about two to four inches and weighing in at under 0.2 pounds.

“Bullfrogs are not native to our area. They’re an Eastern North American species, but they’ve been introduced everywhere, including here in Whatcom County,” notes Nyman. “The problem is that they will eat whatever they can fit in their mouth. They eat smaller frogs, little snakes, even baby Western pond turtles. Bullfrogs are also highly aquatic, just like the Oregon spotted frog. So OSFs are getting eaten, but they’re also competing for the same habitat and resources.”

Solutions to preventing the spread of the bullfrog are few and far between. “It’s really hard to eradicate bullfrogs or even to control them,” says Nyman. “So that’s what we’re worried about, if they become established at sites up here, as they have in lots of other areas, they could really impact these populations.”

Christopher Pearl of the U.S. Geological Survey is leading a study in which Nyman participates that will use audio recordings (3) to listen for the sound of invading bullfrogs. The study will look at the habitat at sites that contain both bullfrogs and the OSF and compare them to habitats with only OSF to see if there is something particular that might keep the bullfrogs at bay, to determine which sites might be most at risk, or whether bullfrog colonization is simply inevitable. 

Although results are preliminary, it appears the bullfrogs could pose a significant threat to the OSF’s survival. “Unfortunately, we found one place where there are bullfrogs very close to where there are Oregon spotted frogs, just upstream and downstream on the Samish River, so that’s kind of a disturbing finding,” notes Nyman. “As far as we know, they’re not in any of the occupied sites yet, but again, some of the places where Oregon spotted frogs occur, including some of the known sites, are just not visited every year by anybody to study or look at the status of the population.” 

Private land ownership limitations also mean that efforts to eradicate or control bullfrog populations in Whatcom County and throughout the OSF’s range would be monumentally difficult and expensive.

Climate Change and an Uncertain Future
“What you really ideally want for Oregon spotted frog is aquatic habitat that goes from relatively deep — which could be three or four feet — to really shallow where the frogs breed, so that, as it begins to dry, the tadpoles still have habitat and in the dry season there is still water around,” explains Nyman. “But with climate change, that is going to be tougher and tougher. If we didn’t do anything, I think a lot of sites just aren’t going to have that persistent water habitat at all that tadpoles need to metamorphose.”

Habitats dependent on rainfall could be the most impacted by the drier summers of a shifting climate. “In the Samish River area that we’re working in, rain — and not snowmelt — is the driving force for hydrology. In the years I’ve been working, it does seem to be drier and warmer in the summertime,” observes Nyman. “In the southern part of the Oregon spotted frog range in Washington in Thurston County, the frogs are breeding earlier and earlier almost every year. Now they’re breeding at the end of January where previously they were breeding in February and into March which is when the frogs breed here. When they breed earlier like that, there’s more chance you could have a frost that will kill the eggs when they’re in their most vulnerable stage.”

Whatcom County Amphibian Monitoring Program Lead Scientist Stephen Nyman and volunteer Kristin Fredericks monitor Oregon spotted frog egg masses at Whatcom Land Trust’s Catalyst Preserve. The monitoring program will survey and count egg masses for five populations in Whatcom County in March 2022, part of a state-wide census for the species.
photo: Chris Brown

This year, Nyman and his team intend to apply for a much larger grant that would focus on ensuring that other parts of the Samish River Preserve get the water that the OSF so dearly need to survive and thrive. “The thought is that we might be able to supply suitable hydrology to one area by redirecting a ditch that currently takes water off the Land Trust property and redirects it to a ditch along the BNSF Railroad,” explains Nyman. “A lot of water that could be useful to the site goes into the ditch and flows right past the property. The railroad doesn’t want the water there, either. If it’s designed properly, getting the water away from the railroad ditch will really benefit the frogs as a stream channel with overflow pools while also preventing the tracks from getting undermined.” 

Efforts in 2022 will also look the potential effects of the drought and flooding in 2021. “We are anxiously — and nervously — awaiting the 2022 breeding season to see if populations suffered,” says Nyman. “It’s very possible that some of the frogs died in some areas and a number of tadpoles didn’t survive this year despite all our efforts because it was such a dry year. Some sites may also have been impacted — either positively or negatively — by the flooding. It’s also hard to say whether the recent low temperatures had any affect — although colder than other recent years, winter conditions are usually not problematic if suitable wintering sites that don’t freeze or don’t trap frogs in low oxygen conditions are available.”

This spring, WCAMP will also provide samples for a WDFW study of the genetics of the OSF to see how isolated watersheds are from one another. “With genetics now you can establish how long things have been isolated by looking at divergence in the DNA itself. We’ll have a much better idea of which frogs are more closely related and which are more distant in each watershed,” explains Nyman. “Our egg mass surveys this spring will be important to this project because you need a number of samples in order to have a statistically valid sample to make these comparisons. That’s where we’re going to need a lot of volunteers to help us out.” 

Those interested in volunteering to join the WCAMP team of citizen scientists can email Nyman to be added to an interest list at Stephen@whatfrogs.org or check the website (https://whatfrogs.wordpress.com), Facebook or Instagram for updates. Training will occur in late February or early March. “In 2022 our partners will be doing a range-wide survey of the species in Washington and Oregon to get as many surveys as possible to get a better idea of the status in its range,” explains Nyman. “We’ll survey egg masses in the early spring, tadpoles later in the spring and then frogs in July, August and September as things dry out. It’s a labor-intensive effort. But if we have five or 10 volunteers it goes a lot faster.”  


Lorraine Wilde, owner of the public relations company Wilde World Communications, has lived in Whatcom County for almost 30 years. She has published more than 350 articles and blogs. Lorraine earned her M.S. in Environmental Science from Western Washington University and cares deeply about this place she calls home.

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