April 13, 2026
Adaptive capacity – the ability of a species, group of species or an ecosystem to cope with or recover from climate-related stressors – is an important component of climate vulnerability assessments.
While there has been research produced on adaptive capacity, including a framework for understanding organizational adaptive capacity published in 2020, much of this previous work has focused on terrestrial species. Freshwater organisms predominantly rely on the temperature of the water around them to regulate their body temperature, which makes their adaptive capacity quite different from terrestrial species. In addition, freshwater systems face a number of stressors and are losing biodiversity at an unprecedented pace. A deeper understanding and wider implementation of adaptive capacity in natural resource management decisions has potential to improve outcomes.
Bringing Together Expertise
In 2023, the Midwest Climate Adaptation Science Center (CASC) gathered scientists and resource management professionals with a wide range of expertise for a workshop in Wisconsin to begin tailoring the adaptive capacity framework to freshwater organisms. The workshop was organized by Olivia LeDee and Holly Embke of the Midwest CASC, alongside David “Bo” Bunnell of the USGS Great Lakes Science Center and Cory Suski of the University of Illinois Urbana-Champaign. Participants represented several geographies across the U.S. and Canada, as well as different areas of expertise.
Their workshop conversations resulted in a March 2026 publication in Global Change Biology Communications titled Adaptive Capacity of Freshwater Organisms in North America: Current Understanding and Future Applications. In it, the authors assess the relevance of adaptive capacity factors for three freshwater taxa, identify key opportunities and gaps in linking trait-based information into adaptive capacity assessments, and illustrate how adaptive capacity can enhance management decisions for freshwater species.
Connecting the Dots
There are two primary challenges when it comes to incorporating adaptive capacity concepts into freshwater fisheries management, Dr. Suski explained. “Firstly, fish populations can vary considerably across locations due to nutrient levels, community composition and population density. Secondly, levels of angler harvest can vary both spatially and temporally, which can influence population dynamics.”
Through workshop discussions, the group began to identify existing practices that, while not explicitly using the term adaptive capacity, get at the same concept. Dr. Embke said, “That was an aha moment for all of us. Connecting adaptive processes to the more common trait-based approaches demonstrated that we didn’t need to start from scratch to understand and operationalize adaptive capacity. There was existing information out there.”
The paper examines three different freshwater taxa: fishes, mussels and crayfish. All three face disproportionate population declines and tend to be heavily managed in freshwater ecosystems. For each taxa, the team used expert knowledge, case studies and a literature review to assess the relevance of adaptive capacity factors, identify opportunities to bridge trait-based information and adaptive capacity assessments and demonstrate how adaptive capacity can inform management decisions. They also surfaced a number of knowledge gaps that should be prioritized in future research.
Real World Case Studies
The case studies examined in the paper illustrate how adaptive capacity concepts can be applied in different ways, depending on context and the needs of management practitioners. The cases highlighted below – spanning threatened and endangered species, recreational management and forecasting environmental change – demonstrate these varying applications.
Coldwater crayfish, a species that only occurs in a small part of the Ozarks region of Missouri and Arkansas, was one of the case study subjects. They face a number of threats, including invasive species, water quality degradation, and climate change impacts. Research on key adaptive capacity factors for coldwater crayfish – their thermal tolerance and vulnerability to stream disturbance – led to the species not being listed under the Endangered Species Act and for thermal refuges to be dismissed as a potential conservation strategy. However, a more integrated consideration of adaptive capacity categories may inform alternative strategies, such as reducing interactions with invasive species and preserving genetic diversity.
Another case study species was lake trout, a recreationally important fish in the Great Lakes, Canada and Alaska. Lake trout display differing morphology – physical features like body size or color, for example – depending on their local environments. “Without explicitly using the term adaptive capacity, fisheries managers have used morphology to understand lake trout feeding strategies and other behavior. They then make stocking decisions according to which morphology is going to be most successful,” Dr. Embke explained. “Using morphology as a tool to link directly to adaptive capacity is an interesting idea, because it’s an easy thing to measure and can give you a lot of information – though there’s more work to be done to quantify that relationship and determine when it can be relied on as a tool.”
A third case study focused on North American freshwater mussels, which are threatened by habitat loss, pollution, invasive species and climate change. Conservation management efforts have long focused on reintroduction and restoration. The success of these strategies relies on nuanced understanding of mussel adaptive capacity factors, such as habitat requirements and physiological tolerances, and must be adapted to align with future environmental conditions.
Key Insights for Better Management Decisions
This paper, and the expert workshop that informed it, fills a gap in vulnerability assessment methodologies by providing a synthesis of the relevance of adaptive capacity factors across three freshwater taxa. By integrating existing trait-based approaches with adaptive capacity frameworks, this research can support more efficient and effective natural resource management decisions.
“The workshop provided a great opportunity to introduce the adaptive capacity framework to scientists and managers focusing on freshwater organisms,” said Dr. Bunnell. “For Great Lakes fish species of restoration or conservation concern, I am excited to explore how we can use this framework to provide actionable science to inform decision makers and stakeholders. Although this framework is typically applied at the species level, it can also be used to help describe the adaptive capacity of populations within a particular species. For example, we could use it to evaluate the adaptive capacity of candidate source populations for a reintroduction effort.”
Future Opportunities
The research team identified key knowledge gaps and opportunities for future research in understanding the adaptive capacity of freshwater species. Several important traits, including genetic diversity, hybridization potential, reproduction and lifespan, are understudied. Data is especially limited for mussels, crayfish and non-salmonid fish species. Incorporating a broader range of expertise and expanding the geographic scope of the research beyond the U.S. and Canada could also provide useful insights.
Many of the workshop participants are continuing to explore adaptive capacity through related projects and management applications. Dr. Suski said, “I was inspired to try and do a better job of pulling adaptive capacity concepts into our research activities – I want to do a better job of filling the gaps identified in the paper and try to deepen the knowledge base of adaptive capacity in freshwater fishes to help improve management outcomes.” After the workshop, he worked with the Illinois Department of Natural Resources to develop a project researching paddlefish physiology and adaptive capacity.