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 great 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 beneath the cover of darkness from tree to tree applying flaps of skin in between their front and rear legs. Taking benefit of air resistance, they can glide about 3 occasions as far as their beginning height when applying their tails as rudders.
These days, southern flying squirrels are routinely located 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 1st to notice their northern creep and continues to stick to their progress. His study 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, practically 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 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 with each other for warmth on frigid winter nights. And make babies.
DNA evaluation would later confirm the strange-searching squirrels have been in reality hybrids and Bowman’s discovery would turn out to be the 1st documented instance of crossbreeding following the expansion of a species’ variety due to modern day climate modify.
To recognize what’s at stake, 1st a brief 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 with each other previously separated species.
Though there are no baseline research to show there are much more hybrids than nature intended, anecdotal proof is mounting.
In the Pacific Northwest, crossings in between 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 different 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 a number of consequences, none of them nicely understood. It could enhance genetic diversity, assisting species climate speedy ecosystem modifications – maybe Mother Nature’s answer to the upheavals humans have wrought.
But if hybrids are far 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 study shows the hybrids have been holding steady for the previous 20 years at just beneath 5 % of the population.
Though they can breed with each and every other and their parent species, they do not look to be carrying out a lot of that and it is almost certainly for the reason that they’re not as nicely suited to the habitat. Northerners are great at withstanding cold, when southerners are great at fighting off illness from warmer climes. Probably their hybrid babies are capable of neither.
What ever the challenge, they do not look to be living extended adequate to breed beyond the 5 % threshold. They might in essence be a genetic dead finish.
But it is really hard to know in advance if a hybrid’s novel mix of genes will harm or enable. A single instance of a genetic gamble that didn’t function out so nicely: Grizzly/polar bear crossbreeds in a German zoo excelled at hunting seals but didn’t have the robust 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 possibly be accountable for their inability to enhance their population, but do not however have final results.
In the meantime, he’s watching closely to see what impact all 3 varieties of squirrels’ habits may possibly have on northern forests. Bowman’s graduate student, Rebekah Persad, for instance not too long ago located 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 significant for the reason that northern forests rely on each spores and nitrogen to generate connections in between roots that enable trees to share water and soil nutrients.
But southern flyers are largely seed eaters, possessing evolved in seed-generating 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 complete ecosystem at danger.
Fortunately, it appears southerners are not fussy eaters and Persad’s early study suggests they – and their hybrid babies – might be switching up their diets to involve fungus.
That could be great news for northern forests. For now, anyway.
As we humans continue to take away barriers in between species, it might imply much more hybrids, along with much more queries about their influence on new habitats.
Catch much more 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 constructive modify
Featured image: Southern flying squirrel. (Photo Credit: James Proffitt)
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