2010 Progress Report: Integrating Future Climate Change and Riparian Land-Use to Forecast the Effects of Stream Warming on Species Invasions and Their Impacts on Native SalmonidsEPA Grant Number: R833834
Title: Integrating Future Climate Change and Riparian Land-Use to Forecast the Effects of Stream Warming on Species Invasions and Their Impacts on Native Salmonids
Investigators: Olden, Julian D. , Torgersen, Christian E. , Lawler, Joshua J. , Beechie, Timothy
Current Investigators: Olden, Julian D. , Torgersen, Christian E. , Lawler, Joshua J.
Institution: University of Washington , Northwest Fisheries Science Center , USGS Forest and Rangeland Ecosystem Science Center
Current Institution: University of Washington , Northwest Fisheries Science Center
EPA Project Officer: Packard, Benjamin H
Project Period: July 1, 2008 through June 30, 2012 (Extended to June 30, 2013)
Project Period Covered by this Report: July 1, 2009 through June 30,2010
Project Amount: $587,209
RFA: Ecological Impacts from the Interactions of Climate Change, Land Use Change and Invasive Species: A Joint Research Solicitation - EPA, USDA (2007) RFA Text | Recipients Lists
Research Category: Global Climate Change , Aquatic Ecosystems , Ecosystems , Climate Change
Climate change, increasing agricultural and urban land-use, and invasive species threaten the functioning of freshwater ecosystems in the Pacific Northwest of the United States. Resource managers, scientists and policy makers are becoming increasingly cognizant that the future will witness simultaneous changes in these factors, yet we still lack the science and decision-support tools required to develop management strategies that are robust to future environmental change.
Our project seeks to develop an analytical framework for linking climate change, riparian landuse, stream thermodynamics, and species invasions for the management and conservation of freshwater ecosystems. We demonstrate this framework for the John Day River, Oregon, where human-induced stream warming is promoting the range expansion of invasive smallmouth bass (Micropterus dolomieu) and northern pikeminnow (Ptychocheilus oregonensis) into formerly uninhabitable reaches that contain critical migration, spawning, and rearing habitat for endangered Chinook salmon (Oncorhynchus tshawytscha). Our proposal has three objectives. First, we will characterize and develop predictive models that forecast spatiotemporal patterns of riverine thermal regimes in response to future climate change and riparian land-use. Second, we will forecast species-specific responses (range contractions and invasions) to projected future thermal regimes. Third, we will evaluate alternative scenarios of climate change to identify critical areas for riparian habitat restoration and protection to mediate future climate-induced warming of streams and species invasions.
Research Element 1: Develop climate-change projections
This task has been completed and was summarized in the 2009 Annual Report.
Research Element 2: Characterize riparian land cover and geomorphology
Elements of this task were reported in the 2009 Annual Report. Here, the extensive habitat surveys of the North Fork and Middle Fork of the John Day River conducted in the summer 2009 are discussed. Overall we surveyed all channel units (e.g. pools, riffles, glides) occurring in 55 km of the North Fork and 50 km of the Middle Fork to describe channel width and depth, substrate, water velocity, and gradient.
Research Element 3: Quantify multi-scaled thermal regimes
Water temperature data for the John Day River has been quantified using a network of past and current digital temperature recorders at point locations. In August 2009 we collected data from 95 temperature recorders (HOBO® Pendant Temperature/Light Data Logger) that were deployed at major confluences, tributaries and other locations throughout the John Day River Basin. Loggers were programmed to record temperature at hour intervals. Stream data from the temperature recorders provides information on daily and seasonal water temperature fluctuations, which is essential to support future modeling efforts. In addition, we have acquired longer-term temperature records from 448 loggers measuring water temperatures between 1993 and 2007 (record length and frequency varies).
We now have a comprehensive understanding of the spatiotemporal patterns in stream temperatures throughout the John Day River Basin. Longitudinal patterns in stream temperatures have been examined and are reported for the North Fork in Figure 1.
Figure 1. Longitudinal temperature profile for the North Fork of the John Day River for August 2009.
Research Element 4: Develop a spatially explicit stream temperature model
In progress: nothing to report at this time.
Research Element 5: Forecast future stream thermal regimes under scenarios of climate change and riparian canopy cover
To predict the effects of climate change on riverine thermal regimes we modeled stream temperature as a function of air temperature, flow velocity, vegetation, and agricultural influence. We did this before considering the mechanistic models of WET-Temp and HeatSource (this research is on-going). We chose to model the annual maximum of the 7-day average daily max (AM7DADM), i.e. the hottest recorded weekly stream temperature when habitat for rearing salmonids is most compressed and the conditions favorable for bass and pikeminnow predation. To predict AM7DADM, we used site-specific metrics of 30-year normal mean annual air temperature PRISM data and mean annual flow velocity (computed using the Unit Runoff and Jobson methods; Research Triangle Institute 2001) and basin-specific metrics of canopy cover and riparian agriculture. We built and validated simple multivariate linear regression models using data for the last two decades. Using the derived relationship, we then mapped stream temperature continuously along the drainage network, and identified reaches that are currently thermally marginal for rearing salmonids during peak summer conditions. “Thermally marginal” is defined as any stream above 25 degrees C at its peak summer temperature, where thermal limits to dispersion were estimated based on field observations. Then, we mapped future stream temperature by producing a map of continuous stream temperature for the year 2080 using the derived linear relationship with projected air temperature input data from a middle-of-the-road emission scenario (ECHAM5 SRES A2), all else being held constant. These results are reported below for Research Element 6.
Research Element 6: Model species responses of Chinook salmon, smallmouth bass and northern
pikeminnow to future thermal regimes.
Our most recent product includes a map of potential habitat loss under the ECHAM5 SRES A2 climate change scenario for Chinook salmon. Similar models for bass and pikeminnow will be constructed using the temperature predictions from WET-Temp or HeatSource. We quantified potential habitat loss by comparing spatially continuous stream temperature maps for current and year 2080 stream temperature scenario. With this information, we located thermally marginal habitat for current normal conditions, and projected potential loss due to climate change for the year 2080. Our results indicate a significant potential compression of rearing habitat—40% of summer rearing habitat will be lost by the year 2080. Bridge Creek and Rock Creek, tributaries of the lower main stem that are currently marginally suitable, will lose all rearing habitat. Other warmer, drier streams, such as Mountain, Wall, and Cottonwood Creeks, will lose 70%, 80%, and 84% respectively. The least habitat will be lost in the upper North and Middle Forks. However, the upper North and Middle Forks are currently where the density of rearing salmonids is greatest. Therefore, even small losses of habitat will affect many individuals.
Research Element 7: Quantity the distribution of Chinook salmon, smallmouth bass and northern
pikeminnow in response to longitudinal heterogeneity in thermal regimes
We conducted an extensive fish and habitat survey in August 2009 and June 2010 to quantify the longitudinal distribution of fish species and essential habitat in the North and Middle Forks of the John Day River Basin (Figure 2). Continuous stream segments comprising 105 river kilometers were systematically surveyed to map and obtain counts of adult fish. Adult fish were located using two-person teams consisting of a diver, equipped with mask and snorkel, and an observer/data recorder on shore. Geographic locations of fish were recorded using a global positioning system with differential correction and 1:24 000 scale topographic maps. Habitat data collected included channel unit type (e.g., pool/riffle), instream cover (i.e., boulder, turbulence, large woody debris, and undercut banks), water temperature, depth, and dominant substrate composition for each channel unit. Additionally we deployed 50 temperature loggers, spaced at approximately 2 km intervals, to determine the longitudinal gradient of temperature over the study area.
Figure 2. Map of the John Day River showing the spatial extent of the fish surveys of the North Fork and Middle fork.
Overall, we documented the distribution of 12 species (Table 1) in August 2009 and June 2010. During August 2009 the overlap between smallmouth bass and chinook declined significantly compared to the spring. Both bass and juvenile chinook moved upstream as stream temperatures warmed and flow declined. Bass were found as far upstream as river km 100 on the North Fork (between Texas Bar and Desolation Creek) and river km 64 (near Big Creek) on the Middle Fork, representing the most upstream observations of bass in the North Fork to date. Smallmouth bass and juvenile chinook overlapped extensively in the downstream areas of our study area in June 2010 when flows were still high and temperatures relatively cool.
Table 1. List of species observed during longitudinal stream surveys.
|Micropterus dolomieu||Catostomus columbianus|
|Ptychocheilus oregonensis||Catostomus macrocheilus|
|Richardsonius balteatus||Lampetra tridentate|
|Rhinichthys osculus||Oncorhynchus mykiss|
|Rhinichthys cataractae||Oncorhynchus tshawytscha|
Other research activities
We have initiated a new project to investigate the behavioral and growth responses of juvenile Chinook salmon to smallmouth bass and northern pikeminnow using a series of mesocosm experiments conducted in an artificial stream channel. This research will provide insight into the mechanisms underpinning the patterns observed in the field, and thus is central to the outputs and outcomes from the EPA project. The first component of the project addresses the question: Are there differences in behavior and vulnerability of juvenile Chinook salmon to native, nonnative, and combined predators? This investigation takes a purely behavioral approach, and examines connections between the genetic basis of predator recognition, prey survival, and behavioral selection by predators. The second component is investigating the implications of increased temperature on the vulnerability of juvenile salmon to the direct (mortality) and indirect (reduced growth) effects of predation. Although many studies have been conducted on the separate effects of predation and temperature, the interaction of the two in a semi-natural environment has seldom been investigated. This integrated approach will fill a significant gap in knowledge of how predator-prey relationships will respond to climate change. Lastly, this study will be the first to compare anti-predator defenses of juvenile Chinook salmon to smallmouth bass (a species native to eastern North America and now present throughout Washington) and northern pikeminnow (a species native to select drainages in north-western North America but now expanding into new regions in the Columbia River Basin). In summary, we view this experimental work as a key data need to support the proposed objectives of the EPA project.