June 2, 2023 3:06 pm

Science Says What? is a month-to-month column written by Wonderful Lakes now contributor Sharon Oosthoek exploring what science can inform us about what’s taking place beneath and above the waves of our beloved Wonderful Lakes and their watershed.

The final couple decades have been very good to southern flying squirrels in the upper reaches of the Wonderful Lakes.

Like other species about the globe, these tree-best dwelling rodents have reacted to warming temperatures by advancing northward. In their case, by gliding below the cover of darkness from tree to tree employing flaps of skin involving their front and rear legs. Taking benefit of air resistance, they can glide about 3 occasions as far as their beginning height although employing their tails as rudders.

Right now, southern flying squirrels are routinely identified in Ontario’s Algonquin Park, roughly 62 miles (one hundred km) from their historic northern limit and solidly in the territory of a separate species of squirrel – northern flying squirrels.

Jeff Bowman, a population ecologist with the Ontario Ministry of Organic Sources and Forestry and a professor at Trent University in Peterborough, was the initial to notice their northern creep and continues to stick to their progress. His investigation is uncovering some intriguing implications.

Back in 2003, he found that exactly where the two species overlapped, some of their babies looked a bit like southerners and a bit like northerners.

When each have protruding, nearly comical-seeking eyes, and can flatten their bodies like furry pancakes for aerodynamic gliding, southern squirrels are smaller sized and have pure white belly fur. The bigger northerners have two-toned gray-white bellies.

But Bowman was obtaining some southern-sized squirrels with mottled grey-white belly fur.

Not surprisingly, he also found each species sharing tree cavities, exactly where squirrels cuddle collectively for warmth on frigid winter nights. And make babies.

DNA evaluation would later confirm the strange-seeking squirrels have been in reality hybrids and Bowman’s discovery would turn out to be the initial documented instance of crossbreeding following the expansion of a species’ variety due to contemporary climate transform.

Jeff Bowman weighing a squirrel. (Photo Credit: James Proffitt)

Hybrids 101

To comprehend what’s at stake, initial a quick primer on hybrids: Crossbreeding wildlife is not new, but human-induced modifications such as worldwide warming, improvement and the introduction of non-native creatures are bringing collectively previously separated species.

When there are no baseline research to show there are extra hybrids than nature intended, anecdotal proof is mounting.

In the Pacific Northwest, crossings involving spotted and barred owls threaten the tiny population of spotted owls whose old development forest habitat has been squeezed by logging. Across western North America, pure cutthroat trout populations have declined as they breed with several introduced species of trout. And in central and eastern North America, the red wolf/coyote cross is a lengthy-standing instance of hybridization resulting from human improvement.

Crossbreeding can have a number of consequences, none of them effectively understood. It could improve genetic diversity, assisting species climate speedy ecosystem modifications – probably Mother Nature’s answer to the upheavals humans have wrought.

But if hybrids are greater suited to a changed habitat than either of their parents, it could lead to the dilution of the genetics of their parent species, even beyond recognition. In that case, the hybrids could turn into the dominant species, or what’s identified as a “swarm.”

Bowman is now fairly confident this is not taking place with the squirrels. His investigation shows the hybrids have been holding steady for the previous 20 years at just below 5 % of the population.

When they can breed with every single other and their parent species, they do not appear to be undertaking a lot of that and it is in all probability mainly because they’re not as effectively suited to the habitat. Northerners are very good at withstanding cold, although southerners are very good at fighting off illness from warmer climes. Possibly their hybrid babies are capable of neither.

What ever the concern, they do not appear to be living lengthy adequate to breed beyond the 5 % threshold. They may possibly in essence be a genetic dead finish.

But it is challenging to know in advance if a hybrid’s novel mix of genes will harm or aid. One particular instance of a genetic gamble that didn’t function out so effectively: Grizzly/polar bear crossbreeds in a German zoo excelled at hunting seals but didn’t have the sturdy swimming skills of their polar forebears.

Bowman and his group not too long ago sequenced the hybrid squirrels’ genomes to figure out what genetic modifications may well be accountable for their inability to improve their population, but do not but have final results.

Graduate student, Rebekah Persad, seeking for truffles (common northern squirrel meals). (Photo Credit: James Proffitt)

Crisis averted?

In the meantime, he’s watching closely to see what impact all 3 varieties of squirrels’ habits may well have on northern forests. Bowman’s graduate student, Rebekah Persad, for instance not too long ago identified their dining preferences have important implications.

Northerners have a tendency to consume fungus – mushrooms and truffles— spreading fungal spores and nitrogen-fixing bacteria as they defecate all through the forest. This is crucial mainly because northern forests rely on each spores and nitrogen to produce connections involving roots that permit trees to share water and soil nutrients.

But southern flyers are largely seed eaters, obtaining evolved in seed-making deciduous forests. If they take more than from their northern cousins in the coniferous forests and do not turn into fungus-eaters, that could place the complete ecosystem at danger.

Fortunately, it appears southerners are not fussy eaters and Persad’s early investigation suggests they – and their hybrid babies – may possibly be switching up their diets to incorporate fungus.

That could be very good news for northern forests. For now, anyway.

As we humans continue to eliminate barriers involving species, it may possibly imply extra hybrids, along with extra queries about their effect on new habitats.

Catch extra news at Wonderful Lakes Now: 

Science Says What? What’s up with dissolved organic carbon (AKA why is my nearby stream murky?)

Science Says What? How 5th-graders counting plants can lead to constructive transform

Featured image: Southern flying squirrel. (Photo Credit: James Proffitt)