Forest Lands Commission tackles role of ‘refugia’
While the Ashland Forest Lands Commission develops a climate adaptation addendum to the Ashland Forest Plan, a recent discussion demonstrated the complexity of a term gaining new meaning in an ecological landscape impacted by climate change: refugia.
In the current forest plan, “refugia” is undefined, according to Forest Lands Commissioner Frank Betlejewski.
“As of right now, we’ve never formally designated a refugia acre under the current forest plan,” Betlejewski said during the Forest Lands Commission meeting Tuesday.
Wildfire Division Chief Chris Chambers said Thursday that he is incorporating input from commissioners and aims to bring a draft addendum to a Forest Lands Commission study session April 11.
Following a public review process, the addendum would go in front of Ashland City Council between mid-summer and early fall. According to the council look ahead, the Forest Lands Commission is tentatively scheduled for a presentation at the first meeting in August.
The draft outlined management of city lands and the greater Ashland watershed as a “single refugium: one patch,” Betlejewski said, covering 1,150 acres on the city side and 14,000 acres managed by the U.S. Forest Service.
Forest Lands Commissioners discussed Tuesday the implications of defining refugia with greater nuance in the forest plan addendum.
Betlejewski presented a table of refugia for three groups (fish, vegetation and wildlife) on one axis and three disturbance types on the other (fire, drought and insects), creating nine dualities of refugia-meets-disturbance.
Generally, refugia in this context “are places that are disturbed less severely or less frequently,” Betlejewski said.
Commissioner Priscila Franco said the table serves as a helpful tool given an urgent need for prioritization in forest management, and that Betlejewski’s presentation filled a gap in understanding about the various scales of refugia — for a salamander versus spotted owl, for example.
“A Del Norte salamander might spend its entire life on eight square meters of forest,” Betlejewski said. “Refugia for an owl might be something like 600 acres. … We’re looking at a question of scale.”
As an example of in-channel refugia, debris jams provide cover over spawning habitat for salmon and steelhead — perhaps representing a quarter-acre of space. Uplands vegetation along streams could be another example of fish refugia, he said.
Working from a premise of using management to create or maintain refugia, “the basic idea is to remove barriers to fish movement and restore stream structure and function,” Betlejewski said.
General technical report 995 released this February from the USFS Pacific Northwest Research Station, titled “Climate change vulnerability and adaptation in southwest Oregon,” will be the “go-to publication for managing for climate change,” Betlejewski said.
Commissioner Nathan Lewis said the refugia-disturbance table represented a useful “schematic” for identifying areas of prioritization.
“The real trick is, what do you prioritize?” Lewis posed. “That’s kind of the battle between all these chapters, saying we’re losing the battle of our soil stability so we need to get more vegetation on the ground, and we’re saying we live in a community that’s probably going to have more fire, so we need to manage for that, and that’s kind of contradictory.”
“If we’re taking care of the fish, we’re probably taking care of everything else on a larger scale,” Franco said. “The difficult task will be how to prioritize … for management to know what to do next.”
As far as vegetation refugia, the Bootleg fire showed that forest areas previously treated with thinning and prescribed fire together emerged from the fire in a stronger overall state than areas without previous treatment or only thinning, Betlejewski said.
Around Crowson Reservoir II, a treated former manzanita patch gave way to horkelia, a plant that likes disturbance and seems to have reoccupied the area, Betlejewski said.
“Right now, we’re focused on management to protect and preserve what’s there,” he said. “We have to start thinking about creating new habitats that these organisms can move into, and in this case, the horkelia is such a great example.”
“Even though we’ve got issues here with climate change and insect activity and fires, we may be a little better suited than some other places to manage for smaller habitat types because we’ve got more to work from to start with,” Betlejewski said.
Marty Main said though the term “refugia” is taking on new meaning, management of the spaces goes back decades on city lands.
“Professionally, the concept of refugia has been primarily disturbance refugia and largely related to fire, wildlife — those have been of higher value in most situations,” Main said.
Maps in 2021 comprehensive climate adaptation research show refugia in the lower watershed and other parcels, as well as units prioritized for limited or no treatment, he said.
Betlejewski said despite the ongoing management, there has never been a formal designation by vote of specific refugia zones.
“The idea of refugia should not be seen as exclusive — that that precludes any human activity,” Commissioner John Owen said. “We’re not trying to go back to the way it was.”
Owen said the idea should be viewed as an “objective that we want to expand,” and means to recognize nature-given models of refugium in the forest, which “we can expand on in our treatments of bringing human activity into it to reassert the more natural ecological progression of the area,” he said.
Report 995 adaptation options for vegetation aim to minimize the “incidence of high-severity, stand-replacing disturbance events” and maintain “spatial diversity of forest stands and age classes” to improve resilience to fire, drought and insects, “thus supporting functional forest ecosystems.”
“Reducing stand density with thinning in dry forests can decrease inter-tree competition and forest drought stress, thus increasing tree growth and vigor,” according to the report summary.
For wildlife, “ecosystem responses to climate change will affect animal species through altered food availability, competition, predator-prey dynamics, and availability of key habitat features (e.g., nesting or resting structures and ephemeral water sources),” according to the report.
In conifer forests, “large-scale disturbance, particularly wildfire” is expected to determine habitat characteristics.
High severity fire can fragment and isolate old-forest patches critical for northern spotted owls and marbled murrelets, and “reduced availability of thermal microrefugia will increase vulnerability to thermal stress for salamanders, small mammals and mesocarnivores,” according to the report.
Adaptation options in sub-alpine forests, woodlands and meadows lean on “thermal and other types of refugia” to “facilitate species persistence with climate change.”
“Increasing spatial variability in stand structures (e.g., stem density and gaps) can increase the extent of refugia in the diverse physiography of southwest Oregon,” according to the report summary. “Fuel reduction and strategic placement of fuel breaks can help to lower fire severity and protect valued habitats.”
At the Almeda fire ignition point near Ashland Pond, restoration project manager Eugene Wier with The Freshwater Trust highlighted the role of refugia in water quality and native fish preservation.
The Freshwater Trust-city of Ashland water quality trading project was designed to mitigate the temperature impacts of wastewater treatment plant discharge by creating stream shade to offset solar loading, Wier said at the site March 3.
Wier defined refugia as a place to rest — fish traveling through impaired water with high daytime temperatures rely on smaller streams or tributaries to spawn, and they have to wait for the right conditions to move.
“If they have to wait in warm water, they lose their vigor quickly,” Wier said. “If they can move into deeper pools where there’s stratified cool water, what we would define as refugia, or there’s cold water inputs coming from the floodplain seeping back in, they’re really good at identifying those places and they'll sit on that until conditions are right for them to move and complete their life cycle.”
Without a place to rest, many fish can die or deplete energy reserves before they have a chance to spawn, Wier said.
“Upper Bear Creek is the most important part for salmon and steelhead because this is where the coldest, best water is in the watershed,” Wier said. “Ashland Creek is its coldest, best tributary, so this project is being implemented here now because this is the farthest upstream, best habitat that we have that needs shade.”
Wastewater treatment plant discharge into Ashland Creek in the late autumn composes most of its flow, and can become too warm for salmon and steelhead to spawn, he said. The city plans to relocate the outfall past Ashland Pond into Bear Creek’s larger mixing zone.
A lesser amount of water expected in the reach of Ashland Creek in the late fall will also be colder, he said, and over time the concerted restoration work in the area will generate deeper pools as wood enters the stream and beavers move in.
“[Fish will] be able to come up into Ashland Creek and wait for flows to pick up in the fall, then they move up into their spawning tributaries,” Wier said. “It’s actually going to result in Ashland Creek being a lot better thermal refugia for fish most of the times of the year.”
When out-migrating smolt move down the creek in the spring, if the water becomes too warm they turn around and swim back upstream toward cold water, and wait there through the summer in the hopes of getting out again next year, he said.
“As they make their way down the creek, they find those thermal refugia, they sit there, it gives them a chance to rest until the conditions are right and they can move again,” Wier said.
If upstream-moving fish encounter an impediment and become stuck in hot water, their last choice is to turn and make a run for the Rogue River before overheating, he said.
According to general technical report 995, adaptation options for fisheries and aquatic habitat focus on “maintaining and diversifying monitoring programs; restoring natural thermal, hydrologic and wood regimes; restoring and maintaining habitat connectivity; and detecting and removing nonnative species.”
Tactics include removing barriers to fish movement, increasing instream flow and cold water retention across the landscape, restoring stream structure and function, and protecting refugial habitats, according to the report summary.
“Anything we can do to create cold pockets on the floodplain in the creek is going to be really important for helping to sustain salmon and steelhead,” Wier said.