California’s recent history of unprecedented drought has brought along with it ever-increasing fire danger and subsequent disaster. With respect to fisheries, fire poses its own unique risks. High-severity fire can destabilize the soils in a basin, exacerbating the effects of sediment loading already caused by roads and other land-uses. Species like trout and other native fishes rely on cool, clean oxygenated water to survive and spawn. Turbid waters resulting from erosion degrade habitat by clouding spawning gravel and decreasing water quality, among other effects.
In areas with species that are endemic (native only to a localized area), severe fire and the resulting effects can mean extinction. In Southern California, where researchers are only just beginning to understand the complexity of the population genetics of steelhead in the region, the risk of fire-exacerbated mass wastage events could mean the loss of entire distinct populations before they are even defined. Furthermore, this is occurring even as conservation efforts work to remove dams to connect those populations back to the Pacific. This risk to fisheries caused by anthropogenic disturbance of fire regimes exists all across California, affecting the Golden trout of the Eastern Sierra to the redband trout of the McCloud River drainage in the southern Cascades. The Feather River country has experienced no exception from massive wildfire, and I recently had the opportunity to learn about ongoing research and assessment on post-fire landscapes that exist in the Basin when I attended the Plumas National Forest Integrated Post-Fire Restoration Symposium.
My primary interest of course was learning about work that was related to fisheries condition in the Basin. Some of the most exciting discussions relating to my own project included analysis of sediment loading from roads in high-severity fire footprints using the Geomorphic Road Analysis and Inventory Package (GRAIP), riparian zone response to fire and its effect on habitat, and the application of eDNA technologies in the detection of pathogens that affect trout here in the North Fork of the Feather River.
The roads analysis was undertaken to identify which road crossings and structures were most likely to fail and those that might have the greatest impact on water quality. The results will be used by the Forest to strategize maintenance and improvements of those critical segments of the road system in a cost effective manner.
Most exciting, perhaps, was the discussion on the application of eDNA analysis in the Feather River Watershed. Researchers from UC Davis sampled locations along the North Fork of the Feather River and its tributaries for the presence of two pathogens: Ceratomyxa shasta, which causes infections of the gastrointestinal tract and other afflictions; and Myxobolus cerebralis, the agent of whirling disease.
Both species of pathogens utilize intermediate hosts, two species of worms, which inhabit sediments and soils. Fire, as mentioned above, can increase the influx of fine sediments to a stream channel. This can thereby increase available habitat for intermediate host species possibly resulting in increased spore counts.
The results of their research, though preliminary, seemed at first indication to be positive in two ways: 1) the detection rate of their eDNA sampling was quite good and 2) Myxobolus cerebralis was not detected. The intermediate host for M. cerebralis, the tubifex worm, was detected but was not of the variety that carries the M. cerebralis spores. This successful application of eDNA in detecting pathogens is significantly good news for the my project (the Upper Feather River Basin-Wide Assessment) organizers as we hope to apply eDNA sampling for these pathogens on a much wider scale in the Basin, possibly in partnership with these other researchers.
Another main takeaway was that while the aftermath of massive fires often looks disastrous, there is often more to these apparent moonscapes than meets the eye. What researchers have been discovering while working in the footprints of the Storrie, Chips Creek, Moonlight, and other fires in the Feather River Basin and across the state, is that post-fire landscapes are not ecological dead zones, but begin reestablishing surprisingly complex ecological dynamics almost as soon as the footprint cools. These dynamics are often found to be dependent not just on the time past since the fire occurred, but also the age and composition of the forest pre-burn and even on the severity of the fire.
So, attending the Plumas National Forest Integrated Post-Fire Restoration Symposium was very valuable in a number of ways. Looking through the lens of my own work it was useful in learning about the fire history of the Basin, the interaction of fire and aquatic habitat, and even provided a little bit of networking opportunity. More generally, the symposium really left me me with the sense that it is possible for agencies to embark on integrated management that truly accounts for the ecology of fire regime and it provided to me a new understanding of the surprising complexity of post-fire ecology.