Over the past decade, cities around the world have increasingly turned to nature-based infrastructure to become more resilient in the face of a changing climate. Urban forests provide shade during heat waves and improve air quality; wetlands filter stormwater and reduce flooding; and restored oyster reefs filter water, create habitat and reduce wave energy along shorelines. When carefully designed and managed, these “nature-based solutions” can support climate adaptation, biodiversity and public health.
There’s a catch, however: Living things are not static building materials. They evolve and adapt in response to changing conditions, sometimes in unpredictable ways. As the climate shifts, the natural systems that humans depend on shift too.
Marina Alberti, professor of urban design and planning at the University of Washington, studies how cities and nature influence one another. In a new article published May 14 in Science, Alberti and collaborators explore how evolutionary change can affect the long-term performance of nature-based solutions.
UW News spoke with Alberti about what’s at stake and how city planners can work with evolution rather than simply reacting to it.
Why did you want to study evolution within nature-based solutions?
MA: Today, an increasing share of infrastructure investment is going to nature-based solutions because they can cost-effectively reduce climate-driven risks to cities while supporting biodiversity, public health and climate adaptation. However, their long-term performance depends on a fundamental biological process that is still rarely considered in design: evolution. These systems are not static infrastructure. They depend on living organisms — plants, microbes, oysters, corals and others — whose traits can shift over time as urban environments change. Cities expose these organisms to heat, drought, flooding, pollution, nutrient enrichment, disease, habitat fragmentation and new species interactions. Those pressures influence which organisms survive, reproduce and continue providing the ecological functions that cities rely on. Over time, ecological and evolutionary responses may alter the very processes that allow these systems to cool neighborhoods, filter water, stabilize shorelines or reduce wave energy.
So the central question is not simply whether a project works on day one. It is whether it can continue to perform as the organisms within it respond to climate stress, urban pressures and the intervention itself.
The problem is that implementation of nature-based solutions is outpacing the science needed to evaluate long-term performance. For these solutions to serve as resilient infrastructure, they must be designed as living, dynamic, evolving systems.
Did you find examples where evolutionary change can affect infrastructure performance?
MA: We found examples showing that evolutionary change can affect traits directly linked to the performance of nature-based solutions. Urban or climate pressures can favor traits that alter the processes these systems rely on, affecting their ability to deliver intended functions.
For example, coastal marsh plants such as Spartina alterniflora are used to stabilize sediment, reduce erosion and help buffer waves. In marshes exposed to excess nutrients from sources such as fertilizer runoff, wastewater, stormwater and upstream land use, however, Spartina can shift biomass allocation toward shoots and away from roots. This shift can reduce the sediment-stabilization function that restoration projects depend on.
In another example, urban tree populations may evolve greater drought tolerance to help them survive hotter and drier periods. But evolutionary responses that improve survival do not necessarily preserve the desired functions for cities. Those trees may persist but grow more slowly or produce less canopy, which could in turn reduce shade, carbon uptake or pollutant removal.
When can evolution strengthen nature-based solutions?
MA: Evolution can strengthen nature-based solutions when populations have enough variation in traits to help them survive and retain their function under changing conditions. Coral reefs are a great example of this. Corals build reef structure, support biodiversity, store carbon and help reduce wave energy along shorelines. But warming seas are driving bleaching and functional decline. To increase their resilience, researchers are testing assisted-evolution approaches, including selective breeding and the use of heat-tolerant coral genotypes. On the Great Barrier Reef, this includes selecting corals that maintain photosynthetic performance and stable symbiotic relationships under heat stress.
These approaches could help sustain reef-based coastal protection as oceans warm, but they also carry risks, including reduced genetic diversity, tradeoffs with other functions and uncertain responses to future conditions.
Oyster reefs show the same principle in another coastal system. Eastern oysters filter water, create habitat, support fisheries and build reef structures that reduce wave energy. They face disease, warming, acidification, eutrophication and low oxygen. Selective breeding and genomic tools can help identify oyster lines better suited to these conditions, but restoration efforts should avoid narrowing genetic diversity. Genetically diverse, site-appropriate stocks are more likely to maintain the functions that coastal communities value.
What were your biggest takeaways from reviewing the available research?
MA: The key lesson is that nature-based solutions are not static assets. Their performance depends on ecological and evolutionary processes that continue after design and deployment.
A second lesson is that context matters. In urban environments, environmental factors, such as temperature, pollution, hydrology and soil conditions, can vary across neighborhoods, blocks and shoreline segments. The same species or design may therefore perform differently in different parts of a city.
Third, variation is central to resilience. Genetic diversity, trait diversity and community diversity can increase the capacity of a system to respond to changing conditions.
Fourth, current adaptation does not guarantee future performance. Populations of organisms in long-urbanized environments may be adapted to present conditions, but those adaptations may not align with future climates.
Finally, a reminder and a caution: Evolution does not necessarily favor the traits that make species effective nature-based solutions. Traits that help organisms persist under urban stress may not be the same traits that support cooling, water filtration, shoreline protection or habitat formation. The challenge for planners is to design and manage these systems so that survival and function remain aligned over time.
What steps can urban designers and planners take?
MA: Planners should design for long-term performance. That means asking: Which organisms provide the desired function? Which traits matter for that function? What environmental pressures will those organisms face? Is there enough genetic, trait or species variation to support future adaptations?
In practice, this means using diverse, site-appropriate source material and considering both local adaptation and future climate conditions. It also means reducing pressures that can weaken performance, such as excess nutrients, contaminants and pollution, while maintaining the habitat conditions organisms need to persist and adapt over time.
It also means monitoring differently. Cities should track not only whether a project is working now, but also whether the organisms, traits and ecological processes that support its performance are changing over time.
Designing nature-based solutions for changing climate conditions requires sustaining genetic diversity, supporting ecological function and maintaining evolutionary potential.
UW co-authors include Anna M. Malesis-Dahm, a doctoral student of urban design and planning. A complete list of co-authors is included with the paper.
This research was funded by the National Science Foundation.
For more information, contact Marina Alberti at malberti@uw.edu.