[MAIPC] FW: [Aliens-L] COYDOGS AND LYNXCATS AND PIZZLIES, OH MY

[Marc Imlay]

Fascinating discussion. 

 

COYDOGS AND LYNXCATS AND PIZZLIES, OH MY

Thanks to human activity, native animals and plants are expected to
hybridize more than ever. Is that a problem — or a solution?

 From: aliens-l-request at list.auckland.ac.nz
<mailto:aliens-l-request at list.auckland.ac.nz>
[mailto:aliens-l-request at list.auckland.ac.nz] On Behalf Of Pamela Zevit
Adamah Consultants
Sent: Tuesday, May 19, 2015 2:31 PM
To: Issg List
Subject: [Aliens-L] COYDOGS AND LYNXCATS AND PIZZLIES, OH MY

  

Pamela Zevit, R.P. Bio 
Adamah Consultants 

Coquitlam BC Canada
604-939-0523 

 <mailto:adamah at telus.net> adamah at telus.net 

Re-connecting People & Nature 

Science World - Scientists in the Schools Ambassador

http://ensia.com/articles/coydogs-and-lynxcats-and-pizzlies-oh-my/ 

May 12, 2015 — Native wolves had been eradicated and the forests of the
eastern United States long cut down when residents of western New York first
began to notice the arrival of coyotes in the 1940s. 

The coyotes of the Rocky Mountains and Great Plains were lithe and quick,
usually weighing less than 30 pounds. The newcomers were different. 

“These things were unique,” says Javier Monzón, an evolutionary biologist at
Stony Brook University in New York. They were bigger and stockier with
larger skulls — all the better to kill white-tailed deer, which were making
a comeback as forests began to regrow. 

Indeed, scientists have since discovered these super-sized coyotes are only
about two-thirds coyote. About 10 percent of their genes belong to domestic
dogs and a quarter comes from wolves, with which they hybridized as they
moved east north of the Great Lakes. “They’re not wolves and they’re not
like pure coyotes from the West,” says Monzón, who has studied the animals’
genetics. Depending on their location, people call them brush wolves,
coydogs, eastern coyotes or coywolves. 

Monzón says hybridization enabled eastern coyotes to adapt quickly to fill
the niche left by wolves. In fact, areas with the highest densities of deer
had coyotes with the greatest proportion of wolf in their genomes. “There
was a very rich resource that was waiting to be exploited,” says Monzón.
“They’ve done very well here.” 

A Nightmare of Our Time 

Some scientists and conservationists see the coywolf as a nightmare of the
Anthropocene — a poster child of mongrelization as plants and animals
reshuffle in response to habitat loss, climate change and invasive species.
Golden-winged warblers increasingly cross with blue-winged warblers in the
U.S. Northeast and eastern Canada. Southern flying squirrels hybridize with
northern flying squirrels as the southern species presses northward in
Ontario. Polar bears mate with grizzlies in the Canadian Arctic along the
Beaufort Sea to produce “pizzly bears.”

All of this interbreeding upsets the conventional notion of species as
discrete, inviolable entities. Moreover, some scientists and
conservationists warn that hybridization will degrade biodiversity as
unusual species are lost to genetic homogenization. 

Partly scientists fear hybrids will be less fit than organisms that have
evolved in place over eons. And often that is true, but the problem solves
itself over time as hybrids lose out in the competitive race for survival. 

“Hybridization is one of the overlooked but clearly very, very important
causes of species’ going extinct.” — Stuart Pimm

Sometimes, however, the hybrids are more fit. Gradually they outcompete
distinctive strains and species, wiping out biological diversity that has
evolved over millennia. Often it is a common generalist species that swamps
and essentially obliterates a rare, specialized and localized species. Many
biologists view such occurrences as a net loss of biodiversity. 

“Hybridization is one of the overlooked but clearly very, very important
causes of species’ going extinct,” says Stuart Pimm, professor of
conservation ecology at Duke University. “Hybridization is a major problem.
It comes from our moving species around, it comes from our changing
habitat.” 

Prime examples are stocked rainbow trout that cross with native cutthroat
trout in the U.S. West, driving rare subspecies into ever-tinier refugia;
common barred owls pushing westward to Oregon and California that cross with
threatened northern spotted owls; and bobcats in northern Minnesota that
hybridize with lynx, posing “an underappreciated factor limiting the
distribution and recovery of lynx,”
<http://www.fs.fed.us/rmrs/docs/pubs/genetics/Schwartz_et_al_conservation_ge
netics.pdf> according to one study. 

As scientists scrutinize genomes, the old idea of separate, radiating
species — an ever-diverging tree of life — has come to be understood as more
of a tangled web.

Fear of the common overwhelming the rare can drive conservation decisions.
For example, in the southeastern United States, wildlife managers are
attempting to sterilize coyotes so they defend territory against other
coyotes but won’t hybridize with the critically endangered red wolf,
recently reintroduced to coastal North Carolina. 

Survive and Prosper 

Other researchers see hybridization differently, though — as a shortcut to
the kind of evolution that has benefited organisms since time immemorial. By
this view, hybridization threatens some species but enables others to
survive and prosper. 

As scientists scrutinize genomes, the old idea of separate, radiating
species — an ever-diverging tree of life — has come to be understood as more
of a tangled web, says Michael L. Arnold, research professor of evolutionary
genetics at the University of Georgia and the author of Evolution Through
Genetic Exchange. Living things evolve into new species only to cross again
and again. 

“Diversity driven by hybridization — it’s an evolutionary phenomenon.” ­—
Michael L. Arnold

Examples include hybridization between polar bears and brown bears long
before modern climate change — during the most recent Ice Age, when shifting
glaciers may have forced polar and grizzly bears into common regions. And
gray wolves in forest regions owe their dark pelage to genes from domestic
dogs — not a black lab of recent heritage, but the dogs that accompanied
early humans from Asia perhaps 14,000 years ago. For that matter, humans
swapped genes with Neanderthals, who survive (genetically speaking) today in
Europeans. 

“Diversity driven by hybridization — it’s an evolutionary phenomenon,” says
Arnold. 

Jim Mallet, a Harvard evolutionary biologist, has discovered thatHeliconius
butterfly species in the Amazon rainforest, far from significant human
interference, have freely crossed with related species. The payoff?
Acquisition of bright, distinctive colors to warn birds that the butterflies
contain cyanide. The butterflies’ defense works only if the birds recognize
it. 

“It’s not just those color pattern genes,” says Mallet. “It’s going on all
over the genome. When you have that level of fluidity, just estimating who
got what from where is becoming really difficult,” says Mallet. 

Scientists who view hybridization as a driver of evolution and biodiversity
say it even has a role to play in future conservation. Rather than try to
protect rare species, such as the red wolf, from hybridization at all costs,
biologists should consider the advantages of “the potential adaptive
benefits from genomic transfers,” Arnold says. 

Opponents of hybridization “might argue it’s less fit if it’s a hybrid,”
says Arnold. “My argument would be, well, maybe it’s more fit. They would
argue that hybridization is destroying biodiversity. And I would argue that
maybe it’s not. Maybe it’s adding to it.” 

The coywolf is as good an example as any — a combination of coyote stealth
and wolf robustness that has helped it adapt to a rapidly changing
landscape. 

This more tolerant view of hybridization has already scored one huge
conservation success story. Faced with an isolated and severely inbred
population of Florida panthers, wildlife managers in the state reinvigorated
the population by releasing eight female cougars of a different subspecies
captured in Texas. Opponents of the move were concerned that hybridization
between subspecies would destroy what was unique about the Florida panther.
But the infusion of new genes saved the population. 

Scientists and conservationists shouldn’t reflexively try to enforce
distinctions between species and subspecies, says Arnold. “I really don’t
like this idea of purity, because if we really push that to its nth degree,
we are a hybrid. So we need to get rid of us.”  <http://ensia.com/> 

 

 

 

 



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