Nature-based Solutions: How restoring habitat protects people and wildlife

Residents of BC’s Lower Mainland are acutely aware of the damaging effects of climate change. In just two years, the region broke multiple records for extreme weather events, including: precipitation, windstorms, snowfalls, heat waves, and drought. 2022 was also the fifth hottest year on record, despite the year falling within the cyclical cooling period of La Nina¹.

These weather events have exposed real vulnerabilities in the ability of the region’s existing infrastructure to cope with, and adapt to, the unfolding climate crisis. During the floods of November 2021, which had devastating effects in the Fraser Valley, further catastrophe was narrowly averted by volunteers whose last-ditch efforts to sandbag the Barrowtown Pump Station prevented it from being overwhelmed by rising floodwaters.

In response, municipalities have already invested heavily to repair and replace floodgates, dikes, and seawalls, to the tune of millions of dollars. While these engineered solutions may be adequate in the short-term, building these structures is often devastating to ecosystems, particularly those found in coastal, riparian, and wetland zones. These lost habitats were once crucial to both people and wildlife in the region; providing habitat, filtering water, and buffering land against floods.

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Nature-based Solutions for addressing climate risks and fostering biodiversity in the Lower Mainland of British Columbia

Working with nature

In the mid-2000s, the International Union for Conservation of Nature (IUCN) pioneered a concept called “Nature-based Solutions.” In a 2016 report, the IUCN describes Nature-based Solutions as actions that protect, restore, or enhance natural and modified ecosystems. These restored ecosystems provide benefits to biodiversity while simultaneously addressing major socio-economic challenges². Nature-based Solutions seek to highlight an aspect of ecosystems that are often forgotten in the discourse around their protection: their direct benefits to human society. They also mark a shift in ecological management, away from industrial society’s mindset of human dominance over nature to one that values the natural environment no differently than the built environment, and acknowledges that the health of ecosystems is inextricably linked to the health of society.

Within the last decade, municipalities have been using this approach to design ‘green infrastructure.’ Examples of green infrastructure include rain gardens, green roofs, and bioswales; natural habitats that capture and store rainwater while boosting urban biodiversity. In 2019, the City of Vancouver adopted its Rain City Strategy, aimed at sustainably managing stormwater through habitat revitalization projects. Out of the Rain City Strategy grew 60 green infrastructure projects that have collectively managed and treated almost 50 million liters of rainwater to date.

Nature-based Solutions to the salmon crisis

Wild Pacific salmon are experiencing unprecedented declines across the coast of BC. Along with climate change and overharvesting, habitat loss is a primary driver. In urban and suburban areas, engineered flood infrastructure such as floodgates, dikes, seawalls, and culverts have dramatically reduced the quality, quantity, and connectivity of salmon habitat. This is evident in the heavily populated Lower Fraser River, where a recent study determined that flood infrastructure has cut off 85% of accessible habitat from salmon. Historically, these habitats were prime locations for juvenile salmon due to their shallow, calm waters and abundant riparian vegetation.

To address these issues, jurisdictions are increasingly turning to Nature-based Solutions. These strategies can benefit struggling salmon populations, while simultaneously mitigating risks to communities from increased flood events. Unlike engineered flood infrastructure, which aims to control the path of water, Nature-based Solutions seek to make room for water by mimicking natural ecosystem processes. An example includes green setback dikes, which allow rivers to flow more freely over floodplain ecosystems. This green infrastructure provides not only habitat for species like salmon, but allows the floodplain habitat to act as a natural sponge for flood water.

Nature-based flood infrastructure is already in action in the Nicola River watershed in the southern interior of BC. A partnership between First Nations, the provincial government, and the BC Wildlife Federation is spurring the construction of almost 100 Beaver Dam Analogues³ (BDAs) throughout the watershed. Designed to mimic the complexity and ecological function of beaver dams, BDAs regulate streamflows and buffer against drought in the summer and floods in the winter. BDAs also create complex, high quality wetland habitat that is crucial for juvenile salmon. This approach demonstrates that Nature-based flood infrastructure can benefit both humans and salmon.

Following the November 2021 Floods, an Indigenous-led group called the Build Back Better, Together Collaborative (BBBTC)⁴ is building momentum for flood planning and mitigation that benefits salmon. Through collaborative workshops with the province, farmers, and other stakeholders, the BBBTC frames flood recovery as an opportunity to restore salmon habitat and advance reconciliation goals.

An economic case

In 2021 alone, climate related impacts cost the province of BC $17.1 billion, a gargantuan sum that is only expected to grow as extreme weather events become more frequent and intense. Currently, large sums of public money are being invested in annual repairs and maintenance to existing infrastructure, only for them to be damaged by the following storm. Compared to traditional infrastructure made of static materials like rock, metal, or concrete, Nature-based Solutions composed of living materials are better poised to adapt to ever-changing climate threats. For instance, shoreline defenses that use native vegetation instead of concrete are more malleable to changing conditions, and able to repair themselves after storms.

In Surrey, the construction of a living dike will provide Boundary Bay and nearby agricultural land a resilient defence against sea level rise, while restoring salt marsh habitat in an area important to juvenile salmon, crustaceans, and migratory birds.

Green space makes urban environments better for people, too

The benefits of green space also apply to the people who live near them. Research shows that people who have access to green space have better health outcomes, including reduced rates of mental illness, obesity, and cardiovascular disease. Green spaces are public gathering places that strengthen community bonds and tackle chronic loneliness. Children who play in green space have better eyesight and develop motor skills earlier. Greenery provides shade, local cooling effects, and absorbs urban noise.

During extreme weather events, green spaces play a critical role in directly protecting people from hazards. On coasts, they buffer shorelines against waves and mitigate floods. In cities, vegetation helps to reduce the “urban heat island effect,” a process where heat during the day is absorbed by paved surfaces and radiated back into the environment at night, preventing the area from truly cooling down.

During the heat dome of 2021, the urban heat island effect played a role in the deaths of 619 people across BC⁵. Strikingly, proximity to green space was a key factor predicting the likelihood of fatality: the less greenery people had in their neighbourhoods, the more likely they were to succumb to heat. What is deeply troubling about this relationship is that low-income neighbourhoods have significantly less green space, their residents are less likely to have air conditioning, and a greater proportion of residents live alone, which are all contributors to higher risk of death during extreme heat.

This finding should serve as a stark reminder of the inequities that exist within our current system. It is also a warning of the consequences of fast-tracking development proposals that override the environmental and social objectives within municipal planning processes in order to rapidly expand the built environment. While the benefits of Nature-based Solutions are abundantly clear, it is also important that decision-makers ensure benefits of green infrastructure are equitably distributed and that their efforts don’t result in gentrification of lower income neighbourhoods.

When it comes to addressing climate change, it may seem like new technologies are the solution. However, the concept of Nature-based Solutions reminds us that, in many cases, the best tools we have to respond to climate risks are the ones which have existed for millenia: the ecosystems of the natural world.

Notes and references

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Raincoast’s in-house scientists, collaborating graduate students, postdoctoral fellows, and professors make us unique among conservation groups. We work with First Nations, academic institutions, government, and other NGOs to build support and inform decisions that protect aquatic and terrestrial ecosystems, and the wildlife that depend on them. We conduct ethically applied, process-oriented, and hypothesis-driven research that has immediate and relevant utility for conservation deliberations and the collective body of scientific knowledge.

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