Climate change: streams, fish, and riparian habitats

Climate change, streams, and riparian areas:

Logging in RHCAs is likely to exacerbate some of the negative effects of climate change on riparian and stream ecosystems. Stream temperature is a primary concern. Actions that minimize increased water temperatures are important for maintaining cold water refugia. The Independent Scientific Advisory Board (2007) states:

“Adequate protection or restoration of riparian buffers along streams is the most effective method of providing summer shade. This action will be most effective in headwater tributaries where shading is crucial for maintaining cool water temperatures. Expanding efforts to protect riparian areas from grazing, logging, development, or other activities that could impact riparian vegetation will help reduce water temperature increases. It will be especially important to ensure that this type of protection is afforded to potential thermal refugia. Removing barriers to fish passage into thermal refugia also should be a high priority.”

Bull trout may lose over 90% of their habitat within the next 50 years due to increased stream temperatures as a result of climate change. Bull trout require very cold headwater streams for spawning, and so are likely to be disproportionately affected by stream temperature increases due to climate change. Recent projections of the loss of suitable habitat for bull trout in the Columbia Basin range from 22% to 92% (ISAB 2007). The US Fish and Wildlife Service notes that:

“[g]lobal climate change threatens bull trout throughout its range in the coterminous United States…..With a warming climate, thermally suitable bull trout spawning and rearing areas are predicted to shrink during warm seasons, in some cases very dramatically, becoming even more isolated from one another under moderate climate change scenarios….Climate change will likely interact with other stressors, such as habitat loss and fragmentation; invasions of nonnative fish; diseases and parasites; predators and competitors; and flow alteration, rendering some current spawning, rearing, and migratory habitats marginal or wholly unsuitable.”

Salmon face serous threats to their continued existence due to climate change, and are predicted to suffer significant habitat loss. The Independent Scientific Advisory Board (2007) notes that according to some research predictions:

“[T]emperature increases alone will render 2% to 7% of current trout habitat in the Pacific Northwest unsuitable by 2030, 5%-20% by 2060, and 8% to 33% by 2090. Salmon habitat may be more severely affected, in part because these fishes can only occupy areas below barriers and are thus restricted to lower, hence warmer, elevations within the region. Salmon habitat loss would be most severe in Oregon and Idaho with potential losses exceeding 40% by 2090.”

Commercial logging in RHCAs would likely exacerbate the issue of high stream temperatures, putting imperiled fish in additional jeopardy. Even localized temperature increases may have negative effects on struggling fish populations, especially when repeated in numerous streams across the landscape. Past and current logging, grazing, and roads have increased stream temperatures to ecologically and legally unacceptable extremes. There is little evidence to support that USFS proposals to log in RHCAs and to focus on tree species composition in RHCAs is an appropriate response or will ameliorate stream temperature problems. High stream temperatures, as well as increased fine sediment in many areas, are likely the pressing risks to fish viability and stream ecosystems. The synergistic effects of climate change, high temperatures, and increased fine sediments warrant actions such as protecting shade, ecosystem integrity, and terrestrial and aquatic connectivity. Wildfire is far less of a threat to these parameters than widespread logging in RHCAs.

Hicks et al. (1991) found base flows increased for 8 to 9 years after clearcut logging because rainfall is not intercepted, evaporated, and transpired by trees. Instead, most rainfall becomes surface, subsurface, or groundwater flow once the trees are removed, and therefore contributes to base flow increases. However, the author found that base flow rates declined to lower than normal volumes in areas of hardwood riparian re-growth for the following 18 of 19 years in their study. This was thought to be due to uptake and ET of stream water by the hardwoods, which had a greater effect on lowering streamflow than conifers. Base flow rates in areas without hardwood re-growth continued to be higher than expected 16 years after logging. The authors predicted base flow rates would return to normal in approximately 40 to 60 years. In addition, Jones & Grant (1996) found that watersheds with drier conditions and more intense summer droughts were more sensitive to the effects of logging and roads on increased peak flows. Logging to increase base flows has been widely cautioned against, and is unpredictable and unlikely to increase base flows during the lowest flow periods or for the long-term. In combination with climate change, unintended negative effects may have severe consequences.

Hutto et al. 2016 note, in relation to climate change, that increased efforts towards fuels reduction would be an untenable emphasis:

“Any perceived problem with future changes in fire behavior cannot be solved by redoubling our effort to treat this particular climate change symptom by installing widespread fuel treatments that do nothing to stop the warming trend, and do little to reduce the extent or severity of weather-driven fires (Gedalof et al. 2005). Therefore, fuel management efforts to reduce undesirable effects of wildfires outside the xeric ponderosa pine forest types could be more strategically directed toward creating fire-safe communities….Fuel treatment efforts more distant from human communities may carry the negative ecological consequences we outlined earlier and do little to stop or mitigate the effects of fires that are increasingly weather driven (Rhodes and Baker 2008, Franklin et al. 2014, Moritz et al. 2014, Odion et al. 2014).”

Logging in streamside corridors is likely to decrease connectivity, especially connectivity in mixed-conifer areas that currently serve as important corridors and are among the last remaining areas that can provide connectivity for species that are associated with mature and complex forests. Commercial logging, in order to be viable, is likely to further incentivize removal of a greater number of trees, and further exacerbate an already concerning situation.

Increasing connectivity is the most commonly recommended strategy for preserving biodiversity in the face of climate change, according to a review of 22 years of scientific recommendations (Heller and Zavaleta 2009). Increasing connectivity includes actions such as removing barriers to species dispersal, locating reserves near each other, and reforestation. Other commonly recommended connectivity-related actions include creating “ecological reserve networks [i.e.,] large reserves, connected by small reserves, stepping stones”; “protecting the “full range of bioclimatic variation”; increasing the number and size of reserves; and creating and managing buffer zones around reserves (Heller and Zavaleta 2009). Large blocks of habitat that are well-connected to each other are important for the long-term survival for many species in the face of climate change.

It is essential that we preserve core habitats and connectivity corridors because these areas are very important for maintaining genetic diversity, facilitating movement and migration, and providing for range and habitat needs. Connectivity corridors also allow for species to colonize new areas or recolonize after disturbances, which will help species adapt to shifts in geographic range due to climate change. Many species are already facing threats to their viability due to fragmentation and a lack of connectivity; climate change threatens to severely exacerbate risks to their continued survival by further fragmenting habitats.

We are concerned about the potential negative effects of logging in RHCAs on numerous bird species, especially those likely to be vulnerable to climate change. Many birds that are threatened by climate change-driven range shifts are also threatened by logging and other practices on the Malheur NF and other NFs in eastern Oregon. Bird species that rely on denser forests and complex canopy structure are also suffering widespread habitat loss due to logging that targets mature mixed-conifer forests—these provide needed complexity and forest density. Logging in RHCAs may have disproportionately negative effects on climate- endangered and climate-threatened birds because RHCAs currently provide some of the best remaining habitat for these birds–many of which breed in eastern Oregon and rely on denser mixed-conifer forests and/or old growth mixed-conifer forests. This includes species such as: Boreal owl; Northern pygmy owl; Northern saw-whet owl; Pine grosbeak; Vaux’s swift; Hermit thrush; Three-toed woodpecker; Varied thrush; Evening grosbeak; Hammond’s flycatcher; Townsend’s warbler; Cordilleran flycatcher; Winter wren; Hairy woodpecker; Great gray owl; and Pine siskin (Csuti et al 1997; Langham et al. 2015). Multiple large timber sales across the Malheur National Forest and other National Forests in eastern Oregon are targeting denser mixed- conifer forests. This represents a significant portion of mixed-conifer forests in the region, and has resulted in widespread degradation and elimination of wildlife habitat for species that depend on these forests. Recommendations need to avoid cumulative impacts to wildlife and aquatic species and their habitats from logging and climate change.

Hutto et al. 2016 note, in relation to climate change, that increased efforts towards fuels reduction would be an untenable emphasis: “Any perceived problem with future changes in fire behavior cannot be solved by redoubling our effort to treat this particular climate change symptom by installing widespread fuel treatments that do nothing to stop the warming trend, and do little to reduce the extent or severity of weather-driven fires (Gedalof et al. 2005). Therefore, fuel management efforts to reduce undesirable effects of wildfires outside the xeric ponderosa pine forest types could be more strategically directed toward creating fire-safe communities….Fuel treatment efforts more distant from human communities may carry the negative ecological consequences we outlined earlier and do little to stop or mitigate the effects of fires that are increasingly weather driven (Rhodes and Baker 2008, Franklin et al. 2014, Moritz et al. 2014, Odion et al. 2014).”

Citations:

Csuti B, Kimerling J, O’Neil T (1997). Atlas of Oregon Wildlife: Distribution, Habitat, and Natural History.

Hutto, R., 1995. Composition of Bird Communities Following Stand-Replacement Fires in Northern Rocky Mountain (U.S.A.) Conservation Biology, Vol. 9, No. 5 (Oct., 1995), pp. 1041-1058

Hutto, R. 2008. The ecological importance of severe wildfires: some like it hot. Ecological Applications, 18(8), 2008, pp. 1827–1834

Hutto, R., Conway, C., Saab, V., and J. Walters. 2008. What constitutes a natural fire regime? Insight from the ecology and distribution of coniferous forest birds in North America. Fire Ecology Special Issue, Vol. 4, No. 2.

Hutto, R. L., R. E. Keane, R. L. Sherriff, C. T. Rota, L. A. Eby, and V. A. Saab. 2016. Toward a more ecologically informed view of severe forest fires. Ecosphere 7(2):e01255. 10.1002/ecs2.1255.

Langham GM, Schuetz JG, Distler T, Soykan CU, Wilsey C (2015) Conservation Status of North American Birds in the Face of Future Climate Change. PLoS ONE 10(9): e0135350.

Moriarty, K.; Epps, C.; Zeilinski, W., 2016. Forest Thinning Changes Movement Patterns and Habitat Use by Pacific Martens. The Journal of Wildlife Management; DOI: 10.1002/jwmg.1060

Oregon Department of Fish and Wildlife. Accessed 2015. Frequently Asked Questions and Sensitive Species List  http://www.dfw.state.or.us/wildlife/diversity/species/docs/SSL_by_category.pdf

Pacific Northwest Research Station (2017) Science Findings: Woodpecker Woes: the Right Tree Can Be Hard to Find. https://www.fs.fed.us/pnw/sciencef/scifi199.pdf

Pierce, J. and Meyer, G. 2008. Long-term fire history from alluvial fan sediments: the role of drought and climate variability and implications for management of Rocky Mountain Forests. International Journal of Wildland Fire. http://www.publish.csiro.au/wf/wf07027

Pilliod, David S.; Bull, Evelyn L.; Hayes, Jane L.; Wales, Barbara C. 2006. Wildlife and invertebrate response to fuel reduction treatments in dry coniferous forests of the Western United States: a synthesis. Gen. Tech. Rep. RMRS-GTR-173. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 34 p.

Pollock, M., Beechie, T., and Imake, H. (2012). Using reference conditions in ecosystem restoration: an example for riparian conifer forests in the Pacific Northwest. ESA journal, 3(11): 98.

Pollock, M. and Beechie, T. 2014. Does Riparian Forest Thinning Enhance Forest Biodiversity? The Ecological Importance of Downed Wood. Journal of American Waters Resource Association (JAWRA) 50(3): 543-559.

Reeves, G. H., Bisson, P. A., Rieman, B. E., & Benda, L. E. (2006). Postfire Logging in Riparian Areas. Conservation Biology, 20(4), 994-1004.

Rhodes, J. J., and W. L. Baker. 2008. Fire probability, fuel treatment effectiveness and ecological tradeoffs in western U.S. public forests. Open Forest Science Journal 1:1–7.

Robertson, B. and Hutto, R., 2007. Is selectively harvested forest an ecological trap for Olive-sided flycatchers? The Cooper Ornithological Society, The Condor 109: 109-121.

Rota, C., 2013. Not all forests are disturbed equally: population dynamics and resource selection of Black-backed Woodpeckers in the Black Hills, South Dakota. Ph.D. Dissertation, University of Missouri-Columbia, MO.

Williams, M. and W. Baker, 2012. Spatially extensive reconstructions show variable-severity fire and heterogeneous structure in historical western United States dry forests. Global Ecology and Biogeography 750 1.11.

Williams, M. and W. L. Baker, W.; 2014. High-severity fire corroborated in historical dry forests of the western United States: response to Fulé et al. Global Ecology and Biogeography 2014.