Sat. May 27th, 2023

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

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

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

Nowadays, 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 All-natural Sources and Forestry and a professor at Trent University in Peterborough, was the very first to notice their northern creep and continues to comply with their progress. His analysis 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-searching 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 discovering 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-searching squirrels have been in truth hybrids and Bowman’s discovery would turn out to be the very first documented instance of crossbreeding following the expansion of a species’ variety due to modern day climate adjust.

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

Hybrids 101

To fully grasp what’s at stake, very first a quick primer on hybrids: Crossbreeding wildlife is not new, but human-induced alterations 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 additional hybrids than nature intended, anecdotal proof is mounting.

In the Pacific Northwest, crossings amongst 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 a variety of 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 quite a few consequences, none of them properly understood. It could enhance genetic diversity, assisting species climate fast ecosystem alterations – probably Mother Nature’s answer to the upheavals humans have wrought.

But if hybrids are much better 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 come to be the dominant species, or what’s identified as a “swarm.”

Bowman is now fairly confident this is not taking place with the squirrels. His analysis 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 carrying out a lot of that and it is likely due to the fact they’re not as properly suited to the habitat. Northerners are very good at withstanding cold, even though southerners are very good at fighting off illness from warmer climes. Maybe their hybrid babies are capable of neither.

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

But it is tough to know in advance if a hybrid’s novel mix of genes will harm or enable. 1 instance of a genetic gamble that didn’t function out so properly: 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 alterations may possibly be accountable for their inability to enhance their population, but do not but have benefits.

Graduate student, Rebekah Persad, searching 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 kinds of squirrels’ habits may possibly have on northern forests. Bowman’s graduate student, Rebekah Persad, for instance not too long ago identified their dining preferences have considerable 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 significant due to the fact northern forests rely on each spores and nitrogen to make connections amongst roots that let trees to share water and soil nutrients.

But southern flyers are mainly 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 come to be fungus-eaters, that could place the entire ecosystem at threat.

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

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

As we humans continue to take away barriers amongst species, it may well imply additional hybrids, along with additional queries about their effect on new habitats.

Catch additional news at Good Lakes Now: 

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

Science Says What? How 5th-graders counting plants can lead to good adjust

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

By Editor