The Biogeography of Climate Change: Animals and Plants That Can Adapt to Global Warming

The anthropogenic climate change we are experiencing today is happening in an instant when compared to the cycles in Earth’s past history. There have been abrupt, flash-in-the-pan changes such as occurred some 65 million years ago leading to the end of dinosaurs. And geologists can mark great extinction events in the past through the fossil record. But there is nothing equivalent to what is occurring today.

Our influence on the global climate is causing extensive habitat loss and temperature swings that are threatening thousands of animal and plant species. So it seems a logical question to ask, what will survive, and indeed thrive, in the world we are remaking because of our industrial activity?

In a paper published in the May 2021 edition of Molecular Ecology, researchers from McGill University in Montreal, Canada, decided to study evolution in real-time and picked as their subject a freshwater fish species, Gasterosteus aculeatus, the Three-spined Stickleback (see picture above). Sticklebacks seem to be a target of many biology research studies. It could be because they live both in fresh and saltwater, can tolerate a wide range of temperatures, come in different shapes and sizes, and exhibit very interesting behaviours not often seen in other species.

The McGill researchers tracked six different fish populations through seasonal environmental changes and sequenced their genomes along the way. What they noted was changes in genetic structures over a single season as habitat shifts occurred. Sticklebacks tend to live in riverine environments that get inundated repeatedly by saltwater or get blocked by sandbars which leave the fish communities isolated in small bodies of brackish water before a fresh inundation once again alters their world.

The seasonal variations of wet and dry, of cold and warm, are reflected in changes to the Sticklebacks genome. In a McGill news release, Alan Garcia-Elfring, lead author in the study is quoted stating:

“The modern version of Darwin’s idea of evolution by natural selection posits that organisms with genes that favour survival and reproduction will tend to leave more offspring than their peers, causing the genes to increase in frequency over generations. As a result, populations become adapted or better-suited to their environments over time. However, this process has typically been studied retrospectively, in populations that adapted to their current environments long in the past. This can make it difficult to understand the sequence of events – for example, which traits were most important and when – that led to their adaptation.”

Garcia-Elfring points out that the McGill study found natural selection at work over a single season, something not previously observed and contrary to the way we think of Darwinian evolution as a process unfolding over multiple generations and years.

If Sticklebacks can readily adapt to dramatic habitat seasonal changes, then does that bode well for other species? One would hope so but currently, we are observing climate-change-induced die-offs at rates 100 to 1,000 times faster than what can be observed from studying our geological past. Sticklebacks are not to be counted out. So what about other species of flora and fauna? Can we identify a bunch that are well suited for rapid adaptive change?

We know one thing: humans can create an artificial environment to shield themselves from the extremes of heat and drought associated with climate change. A good example: think of living in Las Vegas this last week with daytime high temperatures nearing 45 Celsius (113 Fahrenheit). Not all of us can enjoy air conditioning and cocoon ourselves indoors as we wait out a barely livable outside.

A Top Ten Survivors List of Plants and Animals

In a 2014 article appearing in the Smithsonian Magazine, author Helen Thompson writes about ten species of plants and animals that are showing rapid adaptability in the face of climate change. They are:

1. Acropora Hyacinthus – is a coral found off the coast of American Samoa. It appears to tolerate both hot and cool water. Researchers believe Acropora can be transplanted to places where coral bleaching has been extensive, with the hope it can help to repopulate reefs.
2. Thymus Vulgaris – a variety of thyme that produces phenols, chemicals that act as a deterrent to being eaten by herbivores. The plant appears to like the increasingly warmer winters and is spreading and crowding out native species. Because of the phenol, native herbivores have to find new food sources.
3. Oncorhynchus gorbuscha – or Pink Salmon appears to be altering its migratory patterns in response to water temperature changes. Genetic changes have been noted that appear to be associated with the timing of migration.
4. Oncorhynchus nerka – or Sockeye Salmon is changing its migration patterns similar to its cousin the Pink Salmon. Over 60 years because of warmer water temperatures in Washington’s Columbia River, the salmon are adapting by changing when they run.
5. Strix aluco – or Tawny Owls are found in Europe with two types of plumage: brown in the summer and gray in the winter. In Finland where winters are getting milder, over the last 48 years, the preponderance of grey plumage has given way to brown indicating natural selection at work.
6. Wyeomiyia smithii – or Pitcher Plant Mosquitoes, thrive in the swamps and bogs of Eastern North America where its larvae hatch inside the water contained in Pitcher Plants. Entomologists note as temperatures rise, the mosquitoes change hibernation patterns. This is reflected by changes in their genome. Studies of the Asian Tiger Mosquito exhibit similar changes in hibernation periodicity and genome.
7. Cepaea nemoralis – or Banded Snail displays its genetic adaptations by shell colour. The snails with brown shells tend to thrive in cooler environments. Snails with yellow shells thrive in warmer climes. In The Netherlands over the last 43 years, Banded Snail populations are increasingly yellow even in heavily shaded areas where one might expect a darker colour to provide a greater advantage. The snail’s adaptation is in response to warming and the end result is changes in colouration.
8. Tamiasciurus hudsonicus – or Red Squirrel, a species native to Canada’s Yukon territory, is changing when births happen. The rate of change has been twenty days earlier per decade. The reason is earlier spring onsets, greater food availability, and inherited genetic changes manifesting over generations. Interestingly, although Thompson doesn’t mention this, it’s not just Red Squirrels in the Yukon that are exhibiting this adaptability. Here in Toronto, Black and Red Squirrels are also showing signs of adaptation to earlier springs.
9. Drosophila melanogaster – or the Common Fruit Fly in Australia is undergoing genetic mutations all along the continent’s east coast with local flies found in the south exhibiting mutations similar to ones found in the warmer north. These changes to Fruit Flies in Australia is being duplicated in reverse in the Northern Hemisphere with more northerly flies exhibiting mutations found more commonly in the warmer south.
10. Parus major – or Great Tit is a bird that likes to eat caterpillars. Timing of egg-laying coincides with caterpillar hatching. But caterpillars are hatching earlier in the spring than ever before. Somehow the Great Tit has adapted fortuitously, something other bird species may not be capable of doing.

The Stickleback didn’t make the 2014 article’s top ten, but it clearly exhibits all the genetic traits to adapt to the worst that we humans and the environment can throw at it. It’s good to know that our fossil fuel addiction has yet to drive this little fish and other species to extinction. Accelerated evolutionary adaptation can be seen in the above examples working in near real-time.