Research & Technology pages 6 to

Global study finds species can adapt to cities

U of M researchers contribute to largest ever evolutionary field study

RESEARCH & TECHNOLOGY

Emma Rempel, staff As cities expand and are home to more people, scientists are exploring how these landscapes can influence the wildlife that coexist among us. University of Manitoba researchers Colin Garroway and Aleeza Gerstein have contributed to the largest ever field study of parallel evolution. The expansive new study, recently published in the journal Science, looked at whether cities can shape species evolution.

staff Marina Djurdjevic / graphic /

Garroway, associate professor of biological sciences, and Gerstein, assistant professor of microbiology and statistics, joined the project through a chance online encounter.

“By chance Aleeza Gerstein […] and I were both scrolling Twitter at the same time and came across a tweet from Marc Johnson from the [University of Toronto],” said Garroway.

Johnson was proposing a project that was simple in concept but grand in scale. He established the Global Urban Evolution (GLUE) Project as a collaborative field study to answer the question: can organisms adapt to cities?

With volunteers from every inhabited continent, participants would collect samples of white clover in their city to study its evolution in response to urbanization. The project organizers designed simple protocols that could be easily replicated, with participants completing data collection in about one week.

Both Garroway and Gerstein were intrigued, and they volunteered to collect data in Winnipeg as collaborators.

“It seemed very fun to be able to play a small role in a project of this scale,” said Garroway.

Contributions came from 160 cities around the world. This scale allowed the researchers to answer the question of how predictable urban evolution can be.

“This project aimed at understanding the extent to which natural selection in response to urbanization is predictable,” said Garroway.

Natural selection, commonly known as “survival of the fittest,” is the process of an organism’s adaptation to its environment. Those with traits suited to their environment will be more likely to reproduce and pass these traits on to their offspring, who will be more successful than those without the same traits.

The project focused on white clovers because of their global distribution. Participants measured the production of hydrogen cyanide (HCN) in these clovers. This toxic chemical is an antiherbivore defence and is selected for when clovers encounter many herbivores.

HCN also affects a plant’s tolerance of environmental stressors, like frost and drought. This trait, the production of HCN, is only found in plants with dominant forms, or in alleles, of two specific genes, which makes it easy to track in a population.

Researchers wanted to see whether clovers in urban habitats evolved in the same way across the world. They would begin by sampling in urban centres and continued sampling outward until they arrived in a rural region.

The group found that wild plants do adapt to city environments, and that they can adapt quickly. Clovers were found to follow a gradient of HCN production, with clovers closer to urban centres producing less HCN than those in rural habitats. This is because urban clovers have acclimated to city landscapes that are arid, with fewer threats from herbivores.

This response was consistently measured and is evidence of widespread adaptation to urbanization. However, there was variation in HCN production gradients between cities, which could be attributed to differences in environmental factors. Clovers often, but not always, evolved in the same way.

These results have wide-reaching implications that are just beginning to be explored. They suggest adaptation to urban environments is common in plants and wildlife. The ways that organisms adapt to cities could offer insight into their likelihood to survive as a species.

The majority of the world’s human population live in villages, towns or cities. Cities have been designed to meet the needs of many people in a relatively small area, so there are many similarities in their design across the globe.

These structural resemblances also create similar environmental conditions for the many species that live in and around cities. The environments in cities as distant as Toronto and Tokyo are more similar to each other than either is to its nearest rural habitats.

“Human activities are the most notable and efficient causes of contemporary evolution,” said Garroway.

“Human activities are the most notable and efficient causes of contemporary evolution”

— Colin Garroway, associate professor

or “anti-life.” A new hypothesis is gaining ground among evolutionary biologists that views cities as drivers of evolution. Cities impose harsh environmental pressures on the species that inhabit them, both directly and indirectly. This selective pressure can make cities sites for major evolutionary change.

This research shows we are not removed from nature, but exert our influence over it every day. The changes we make to our environment can change the evolutionary potential of plants and animals, so it is important to consider our connections to nature when designing our cities. Whether that means increasing or preserving green spaces in downtown areas, we can design cities to benefit our wildlife neighbours.

“For better or worse, we are a part of a new type of nature,” Garroway said.

“Cities and people are nature, and we are changing the ‘natural’ status quo. I think this is fun and important to think about.”

Nuchatlaht could change land claims for good

Nootka Island, a site of colonial expropriation for centuries, has come full circle

COMMENT

Lucas Edmond, staff Nootka Island rests off the west coast of Vancouver Island and has been a site of colonial contestation for centuries. In the late 1700s, the inlet east of Nootka Island was geographically important for trade due to its calm shelter from ocean currents. As such, the Spaniards, who initially laid colonial claim to North America’s West Coast, took exception to British presence in the inlet due to contradicting definitions of sovereignty. The Spanish claimed they had discovered the area first, while the British noted that to claim land, nations must settle it first — of course, each claim was bogus, considering a handful of Indigenous nations occupied the land before Europeans were ever aware of its existence. War over the land claim was ultimately avoided through the Nootka Sound Convention, which recognized both colonial powers’ rights to fish, trade, navigate and settle the area.

Fast forward to 1846 and Spanish presence on Vancouver Island had faded. Instead of the Spanish, the United States and Britain were vying for sovereignty over the West Coast. The issue was one of the most consequential moments of each colonial state’s history. Bargaining for land on the West Coast became so important that it influenced the election of president James K. Polk in 1844, whose slogan was “54-40 or fight!” — referencing the parallels where he wished to draw the Canada-U.S. border. Keen to avoid another war with the U.S., the British agreed to draw the border at the 49th parallel, which officially transitioned Nootka Island, according to British law, into Crown land.

The problem with these grand claims to sovereignty is that each state failed to recognize unceded Indigenous territory. Claims to sovereignty were often made via arguments of discovery or terra nullius — a Eurocentric law that only recognized property rights if groups or individuals cultivated land according to western-defined agricultural methods — even though the land was already used to support the lives of various Indigenous groups.

As Audra Simpson writes in her seminal book Mohawk Interruptus: Political Life Across the Borders of Settler States, “the United States and Canada can only come into political being because of Indigenous dispossession […] Those who still live this struggle with different political authorities find themselves in a ‘nested’ form of sovereignty and in politics of refusal.”

Now, 176 years later, the Nuchatlaht First Nation is refusing to recognize Canadian sovereignty over their hereditary land, which encompasses about 200 square kilometres of Nootka Island. Centuries of western contestation, deliberation and dispossession have come full circle and the Nuchatlaht are making their case for getting their land back in the Supreme Court of British Columbia.

The Nuchatlaht claim centuries of commercial activity on their land have benefited everybody but them, and they are right to argue this. The Nuchatlaht were virtually evicted from their land following the 1846 border agreement.

After 1846, Nootka Island was turned into Crown land and expropriated without consultation or treaty. This meant cutting trees or building settlements without a lease was illegal. The Nuchatlaht were subsequently alienated and dispossessed from their land which forced them to settle off the island.

B.C.’s provincial government has obscured this fact and claims the Nuchatlaht abandoned the land, giving the province legal tenure to manage resources on the island and dish out contracts and licenses to extractive industries. As a result, the forestry industry has clearcut nearly 80 per cent of the island’s old-growth forest. Further, industrial activity has decimated spawning rivers for salmon and threatened fishing communities’ livelihoods downstream. Not only has the Canadian government dispossessed the Nuchatlaht of their land, but it is rapidly decimating the region’s surrounding ecology — consequently giving haste to community members who are desperate to save what they can.

Beyond just Nootka, this case may be a turning point for Indigenous land claims in B.C. and potentially Canada. It is the first time that an Indigenous group seeking their land back will use the Tsilhqot’in land ruling as precedent. In 2014, the Supreme Court of Canada ruled the Tsilhqot’in were entitled to over 1,700 square kilometres of their hereditary lands outside of reserve sites. Because the group was semi-nomadic, the B.C. provincial government argued the Tsilhqot’in should only receive village sites back. However, for the first time, the highest court in Canada recognized sovereignty based on semi-nomadic lifestyles and incorporated the land linking these settlements. In sum, it was a massive overturning of traditional property law and centuries of terra nullius that had hampered so many Indigenous land claims in the past.

staff Dallin Chicoine / graphic /

Centuries of western contestation, deliberation and dispossession have come full circle and the Nuchatlaht are making their case for their land back in the Supreme Court of British Columbia

Although the Nuchatlaht First Nation is a small community consisting of 151 members, it has the potential to make a massive splash in the Canadian legal community. Indigenous land claims consistently have to prove their lineages’ use of land within a biased settler framework. In a sense, they have to play a game where the rules are defined and redefined by their competitor.

The case the Nuchatlaht are currently upholding not only has the potential to reclaim land that has been juggled by the international community for centuries, it could also be the site that redefines the very parameters that have distinguished and marginalized many Indigenous claims to sovereignty from Canada’s systemically biased legal mechanisms. Precedent was set by the Tsilhqot’in, but it will be cemented by Nuchatlaht, should their case stand. Nootka Island finds itself at yet another crucial historical juncture, but this time it’s the island’s Indigenous people leading the way.