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 fantastic to southern flying squirrels in the upper reaches of the Good Lakes.
Like other species about the planet, 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 instances as far as their beginning height though 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 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 adhere 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.
Though each have protruding, just about comical-hunting 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 acquiring 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-hunting 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 contemporary climate transform.
To comprehend 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.
Though there are no baseline research to show there are additional 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 a variety of introduced species of trout. And in central and eastern North America, the red wolf/coyote cross is a extended-standing instance of hybridization resulting from human improvement.
Crossbreeding can have numerous consequences, none of them properly understood. It could improve genetic diversity, assisting species climate speedy ecosystem alterations – maybe Mother Nature’s answer to the upheavals humans have wrought.
But if hybrids are improved 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 out to be the dominant species, or what’s recognized as a “swarm.”
Bowman is now quite 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.
Though they can breed with every other and their parent species, they do not look to be carrying out a lot of that and it is possibly since they’re not as properly suited to the habitat. Northerners are fantastic at withstanding cold, though southerners are fantastic at fighting off illness from warmer climes. Maybe their hybrid babies are capable of neither.
What ever the concern, they do not look to be living extended sufficient to breed beyond the 5 % threshold. They could in essence be a genetic dead finish.
But it is difficult 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 powerful swimming skills of their polar forebears.
Bowman and his group lately sequenced the hybrid squirrels’ genomes to figure out what genetic alterations may well be accountable for their inability to improve their population, but do not but have outcomes.
In the meantime, he’s watching closely to see what impact all 3 forms of squirrels’ habits may well have on northern forests. Bowman’s graduate student, Rebekah Persad, for instance lately identified their dining preferences have substantial 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 critical since northern forests rely on each spores and nitrogen to produce connections involving roots that let trees to share water and soil nutrients.
But southern flyers are largely seed eaters, possessing evolved in seed-making deciduous forests. If they take more than from their northern cousins in the coniferous forests and do not turn out to be fungus-eaters, that could place the entire ecosystem at threat.
Fortunately, it appears southerners are not fussy eaters and Persad’s early investigation suggests they – and their hybrid babies – could be switching up their diets to consist of fungus.
That could be fantastic news for northern forests. For now, anyway.
As we humans continue to eliminate barriers involving species, it could imply additional hybrids, along with additional queries about their influence on new habitats.
Catch additional news at Good Lakes Now:
Science Says What? What’s up with dissolved organic carbon (AKA why is my neighborhood stream murky?)
Science Says What? How 5th-graders counting plants can lead to good transform
Featured image: Southern flying squirrel. (Photo Credit: James Proffitt)