Invasive species are an ongoing focus of the NW CASC’s efforts to fund and facilitate actionable science, which have included research on more than 24 invasive species since 2011 across Northwestern habitats ranging from Puget Sound prairies to sagebrush steppe, from coastal wetlands to high elevation forests. In 2024 alone, NW CASC invested over $650,000 in research on invasive species, and the CASC program nationwide invested over $4 million.
As part of these efforts, NW CASC hosts the Northwest Regional Invasive Species and Climate Change (NW RISCC) Network, a partnership of regional agencies and organizations dedicated to helping practitioners address the nexus of climate change and invasive species, including plants, animals and pathogens. This partnership has contributed to state and local preparedness in the region by identifying priority research needs, connecting researchers with practitioners through meetings and events, and by synthesizing, summarizing, and sharing information on topics of emerging concern. You can stay up-to-date on upcoming NW RISCC events, resources and more by subscribing to the NW RISCC listserv or by visiting nwriscc.org.
As part of this issue’s Science Spotlight, we’re sharing a new, NW RISCC management brief on the invasive European Green Crab, as well as an update on recent NW CASC research addressing interacting invasive species in the Columbia River Basin.
Don’t Get Crabby, Get Proactive! Check out a New NW RISCC Management Brief on the European Green Crab
The European green crab has received significant attention for its known and potential economic, cultural, and ecological impacts in the Northwest and beyond. Check out the NW RISCC Network’s latest Management Brief for information on the ways warming temperatures are influencing this ongoing invasion and management efforts. Learn more on the NW RISCC website or download the management brief below:
Recent NW CASC Research Addresses on Interacting Invasive Species in the Columbia River Basin
Changes in our climate not only influence how invasive species affect native species, but also how invasive species interact with each other, and how these complex interactions shape their overall impact in a landscape. Despite the climate-driven increase in multi-species invasions, many management tools are limited by their ability to account for only a single invasive species. In response to this limitation, recent NW CASC-supported research — led by University of Washington’s Julian Olden — used a case study of interacting invasive species in the Columbia River Basin to develop strategies for helping resource managers predict the ecological outcomes of multi-species invasions, evaluate tradeoffs of management strategies, and improve the resilience of freshwater ecosystems to increasing water temperatures. Olden partnered with Columbia River Inter-Tribal Fish Commission, Confederated Tribes of the Warm Springs Reservation of Oregon, Oregon Department of Fish and Wildlife, and the U.S. Fish and Wildlife Service, to understand how interactions between invasive smallmouth bass and invasive rusty crayfish are affecting spring Chinook salmon and summer steelhead in the Columbia River Basin and how to help resource managers develop strategies for minimizing their impact.
In Oregon’s John Day River, both invasive smallmouth bass and invasive rusty crayfish directly affect salmonids by preying on juveniles, and indirectly affect salmonids through competition. These two invasive species also have a complicated relationship with each other. Adult smallmouth bass feed on rusty crayfish, while rusty crayfish feed on smallmouth bass eggs and juveniles. These dynamic interactions likely vary across the basin, depending on the water temperature, which helps determine these species’ feeding rates and other behaviors. Though these basic interactions are known, the uncertainty lies in how continued, climate-induced stream warming will influence their impact on salmonids and what strategies will be effective in managing them.
To help answer this question, the research team used a new, network version of an individual-based modeling framework, HexSim, to simulate the population dynamics of the two invasives under varying future conditions. By identifying high-risk introduction sites and predicting how invasions may play out over time, this model enables resource managers to understand different scenarios and evaluate the tradeoffs of different management actions. To learn about the findings from this recently completed project, stay tuned for an upcoming publication, which will be shared in a future issue of NW CASC Connections.
Protecting our Region from Invasive Species in a Changing Climate
This work is just one example of how the Northwest Climate Adaptation Science Center is helping our region protect culturally and economically important species from the increasing threats of invasive species in a changing climate. In our upcoming newsletters, we’ll be diving into more of NW CASC’s work on invasives species, fire and partnerships!