How flora and fauna are evolving before our eyes, in the face of climate adversity

During Britain’s industrial revolution, the peppered moth became one of the most famous examples of rapid evolution. The black and white insect, widespread in the northern hemisphere, largely disappeared from urban areas in England as its habitat became covered with factory soot. In its place, a black form of the moth dominated, blending in with its new surroundings, better able to hide from birds and other predators. As air quality improved in the 20th century, black and white moths experienced a resurgence in urban areas.

For scientists, the humble peppered moth is one of thousands of examples of how humanity is impacting the natural world, forcing other species to adapt to our dominance of Earth.

At the end of 2024, I asked researchers for modern day examples they had seen in their work. I received dozens of responses. Shrinking mahogany trees, a brittle star almost exclusively found in beer bottles discarded by fisherman and city snails evolving paler shells to counter city heat were among the most striking examples that we documented in an article this week. But there were many more we did not have space to publish.

More on some of our world’s most magnificent, resilient creatures, after this week’s most important reads. And do keep up with the latest from Los Angeles’s devastating wildfires on our live blog here.

One fascinating example was offered to me by Dr Irina Druzhinina, senior mycologist with Kew’s Royal Botanic Gardens, who pointed out how the construction of Britain’s railway network in the 19th and 20th century turbocharged the spread of Serpula lacrymans, better known as dry rot fungus. It is a homeowner’s nightmare, causing millions of pounds of damage to UK homes every year by breaking down the parts of timber that give wood its strength. Druzhinina told me the fungus was spread around the country by the growth of train travel.

“As railways expanded, large quantities of untreated or poorly treated timber were used in construction, including sleepers, bridges, and railway buildings. These materials provided an ideal environment for the fungus to spread and proliferate,” she explained. “The movement of infected wood in sleepers or crates inadvertently helped the fungus spread across regions. It is why we now have concrete sleepers all around even though the wood is better for railways.”

Differences between cities and the countryside was also a common theme in responses, including a recent paper on differences in body sizes among African dwarf chameleons. The urban heat effect, meaning that towns and cities are usually significantly warmer than surrounding rural areas, also featured a lot.

Dr. Barbara Gravendeel, a botanist with Naturalis Biodiversity Center in the Netherlands, pointed to the example of dandelions that grow faster and flower earlier in urban areas.

“We collected seeds from common dandelion (Taraxacum officinale) individuals along an urban–rural gradient in Amsterdam to study how these plants evolve in response to urban heat. Urban dandelions grow faster at elevated temperatures and require shorter cold periods to induce flowering, as compared to dandelions from rural populations,” she said.

Creeping woodsorrel, another common plant in the northern hemisphere, has redder leaves in urban areas to combat heat stress while keeping greener leaves in cooler rural habitat, Japanese researchers found in 2023.

Many researchers said there are are likely thousands more examples around the world waiting to be discovered. If you would like to get involved in finding them, citizen science apps like iNaturalist are a great way to help researchers spot differences across large areas. Happy searching.

Read more on biodiversity:

The good news

The bad news

Down to Earth readers on the eco-friendly changes they made for the planet

Canadian reader Kerri Seifried emailed in about a recent change to her home that will yield both short and long-term benefits for her and the planet: installing solar panels.

“In the past 12 months I have installed solar panels that should generate 100% of our electricity use – and then we installed a heat pump, which should replace our outdated and unsafe furnace and reduce our consumption.”

“We really won’t know what the net effect will be until next August,” she warns, but she is undoubtedly optimistic.

“We live in British Columbia, and there are incentives from the federal and provincial governments for these improvements. None come close to covering the total costs but they are very welcome just the same. I feel it will be about 10 years before we recoup the outlays, but as our furnace needed replacing anyways, it was a good time to switch.”

Let us know the positive change you’ve made in your life by replying to this newsletter, or emailing us on downtoearth@theguardian.com

Profiling the Earth’s most at-risk animals

Location: The Galápagos, Coral Triangle, coastal east Africa
Status: Near threatened

The bullet-shaped Albacore tuna migrate in schools throughout the Mediterranean and travel in single species schools, without the level of mixing as seen in other species. Tuna are important as they are a top predator in the food chain and maintain a balanced environment.

For more on wildlife at threat, visit the Age of Extinction page here

One image that sums up the week in environmental news

Credit: Chew Valley Plants Trees

Reporting from England’s Chew valley in Somerset, Jamie Grierson met a determined group of 1,000 climate-concerned citizens, who have embarked on a noble project: planting 100,000 trees in an effort to boost biodiversity and reduce flooding in the area.

“There are about 30 helpers, split into pairs, carefully planting hawthorn, blackthorn and crab apple saplings, one tree at a time,” Jamie reports. “Undaunted by the scale of the project, they are planting one of the biggest new woodlands in England.”

For more of the week’s best environmental pictures, catch up on The Week in Wildlife here