Study Finds Climate Change Accelerates Hybridization Between Native, Invasive Trout
MISSOULA – A new article by researchers from the University of Montana, the U.S. Geological Survey and Montana Fish, Wildlife & Parks asserts that climate warming is increasing the hybridization of trout – interbreeding between native and non-native species – in the interior western United States.
Clint Muhlfeld, a research assistant professor in the UM Division of Biological Sciences’ Flathead Lake Biological Station and research ecologist with the USGS Northern Rocky Mountain Science Center in Glacier National Park, is the lead author of the article, titled “Invasive hybridization in a threatened species is accelerated by climate change,” which was published in the latest issue of Nature Climate Change. Co-authors are Ryan Kovach, a postdoctoral scholar at UM’s Flathead Lake Biological Station, and Leslie Jones, a UM doctoral student who works with Muhlfeld and USGS.
Specifically, rapid increases in stream temperature and decreases in spring flow over the past several decades contributed to the spread of hybridization between native westslope cutthroat trout and the introduced rainbow trout – the world’s most widely introduced invasive fish – across the Flathead River system in Montana and British Columbia, Canada.
Experts have hypothesized that climate change could decrease worldwide biodiversity through cross-breeding between invasive and native species, but this study is the first to directly and scientifically support this prediction. The study was based on 30 years of research by scientists with UM, USGS and Montana FWP.
Hybridization has contributed to the decline and extinction of many native fishes worldwide, including all subspecies of cutthroat trout in western North America, which have enormous ecological and socioeconomic value. The researchers used long-term genetic monitoring data coupled with high-resolution climate and stream temperature predictions to measure whether climate warming enhances interactions between native and non-native species through hybridization.
“Climatic changes are threatening highly prized native trout as introduced rainbow trout continue to expand their range and hybridize with native populations through climate-induced ‘windows of opportunity,’ putting many populations and species at greater risk than previously thought,” Muhlfeld said.
“The study illustrates that protecting genetic integrity and diversity of native species will be incredibly challenging when species are threatened with climate-induced invasive hybridization,” he said.
Westslope cutthroat trout and rainbow trout both spawn in the spring and can produce fertile offspring when they interbreed. Over time, a mating population of native and non-native fish will result in only hybrid individuals with substantially reduced fitness because their genomes have been altered by non-native genes that are maladapted to the local environment. Protecting and maintaining the genetic integrity of native species is important for a species’ ability to be resilient and better adapt to a rapidly changing climate.
Historical genetic samples revealed that hybridization between the two species was largely confined to one downstream Flathead River population. However, the study noted, during the past 30 years, hybridization rapidly spread upstream, irreversibly reducing the genetic integrity of native westslope cutthroat trout populations. Genetically pure populations of westslope cutthroat trout are known to occupy less than 10 percent of their historical range.
The rapid increase in hybridization was associated with climatic changes in the region. From 1978 to 2008, the rate of warming nearly tripled in the Flathead basin, resulting in earlier spring runoff, lower spring flooding and flows, and warming summer stream temperatures. Those locations with the greatest changes in stream flow and temperature experienced the greatest increases in hybridization.
Relative to cutthroat trout, rainbow trout prefer these climate-induced changes and tolerate greater environmental disturbance. These conditions likely have enhanced rainbow trout spawning and population numbers, leading to massive expansion of hybridization with westslope cutthroat trout.
“The evolutionary consequences of climate change are one of our greatest areas of uncertainty because empirical data addressing this issue are extraordinarily rare,” Kovach said. “This study is a tremendous step forward in our understanding of how climate change can influence evolutionary process and ultimately species biodiversity.”
Overall, aquatic ecosystems in western North America are predicted to experience earlier snowmelt in the spring, reduced late spring and summer flows, warmer and drier summers, and increased water temperatures – all of which indicate increased hybridization between these species.
Additional UM-affiliated authors are UM Wildlife Biology Program Director Winsor Lowe, UM Associate Professor of Conservation Ecology Gordon Luikart and Regents Professor Emeritus Fred Allendorf. Authors not affiliated with UM are Robert Al-Chokhachy with the USGS Northern Rocky Mountain Science Center, Matthew Boyer with Montana FWP in Kalispell and Robb Leary with Montana FWP in Missoula.
The study was supported by the Great Northern Landscape Conservation Cooperative, the U.S. Department of the Interior’s Northwest Climate Science Center, the National Climate Change and Wildlife Science Center, the National Science Foundation and Bonneville Power Administration.
The article can be viewed online at http://dx.doi.org/10.1038/nclimate2252. For more information call Muhlfeld at 406-600-9686 or email cmuhlfeld@usgs.gov.
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* The Warm List – seen here: http://www.numberwatch.co.uk/warmlist.htm
Personally, sex is of the menu at temps above 20°C 68 F
I heard this story on NPR yesterday. As a regular listener, I can tell you that this type of story is almost a daily occurrence. The validity of the claims that such and such ecological trend or change is manmade is never questioned. Much of the public has just been brainwashed about such things and will never question it. They are taught this either implicitly or explicitly in public schools from their earliest years. It is a self inflicted public disaster, IMO.
@ur momisugly Steve Reddish
If your pure-bred Shitzu breeds with a Bulldog you get a BullShit 🙂
Here is another man made hybrid trout.
http://en.wikipedia.org/wiki/Splake
They have introduced these into Maine waters for years. I prefer the native brookies myself.
From the abstract [my emphasis]:
So hybridization was happening already on the Flathead River system. [abstract]
Does anyone know what their “stream temperature predictions” means?
Could less water in the river system mean closer proximity to the other species? Could this increase rates of mating without higher water temperature?
So they write:
Specifically, rapid increases in stream temperature and decreases in spring flow over the past several decades contributed to the spread of hybridization between native westslope cutthroat trout and the introduced rainbow trout – the world’s most widely introduced invasive fish.<b?.
So, man intrudes invasive species, invasive species takes over, man blames climate change!
IMHO, the stupid hurts!!
oops, should be introduces invasive species.
[That would depend, would it not, on both where man is intruding into the various species, and what he is intruding. 8<) .mod]
From the abstract above:
Below are some earlier paper / abstracts on the 2 trout in the Flatbead River system and geographically similar areas.
This article is such a piece of nonsense it is hard to know where to start:
1. Rainbows and Cutthroat can interbreed to produce fertile offspring because they are the same species.
2. If Rainbows and Cutthroat are a different species, then black people and white people are also a different species.
3. Genetics tells us that hybrids are almost always better adapted, because they have a wider range of genes to select from. We see this in US sports, where hybrid black-whites outperform pure whites and pure blacks.
4. the rainbows were introduced by humans, not by climate change.
Invasive hybridization in a threatened species is accelerated by climate change
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the hybrid has a wider range of genes to select from. thus they are better able to adapt to a range of conditions as compared to the pure-bred stock.
however, the fallacy of the argument is revealed when one replaces “trout” with “human”. For example, consider Hawaii. Native Hawaiians are all but extinct. Japanese and Filipino were introduced to Hawaii and interbred with the local population. These hybrids then replaced the pure-breds as children replace their parents. No climate change was required.
The same process is now underway in the continental US. Eventually hybrid black-white-brown-yellow-red children will replace their pure-bred parents. It doesn’t require climate change. All it requires is that sexual attraction be color blind.
I’m starting to feel sympathy for Climate Change. It’s being blamed for everything damn thing that goes wrong.
I mean really, if you were a strapping, virile cutthroat and a sexy young rainbow came along, what would you do?
I’ve watched a brook trout stalk its prey. It followed a soon to be eaten grasshopper struggling in the wet grass along a small creek. It took several minutes and was fascinating, like watching a female lion creep up on a gazelle. The brookie eventually knocked it off a blade of grass, it fell into the water, and the brook got its much deserved breakfast. Rainbows are more like, if it swims near me I’ll eat it otherwise forget it. And a small throw back brookie will feel like a swordfish on your hook compared to a rainbow! Brookies were introduced into Wallowa County rivers and can successfully outcompete rainbows for food. Oh well. It is what it is. No skin off my nose. I’ll catch and eat both species, even freezing them in the OMG same freezer bag! I guess that makes me such a bad girl.
ninety-nine percent of the rest of the people couldn’t tell a cut from a rainbow, let alone prize one over the other.
==============
the same scientists that tell us that cutthroat and rainbows are different species will tell us that black and white humans are the same species.
the same scientists that tell us that cutthroat and rainbows are different species will tell us that all dogs are the same species, no matter how different they may look.
so explain why it is that a great dane and chihuahua, which can breed and produce viable offspring, how it is that these are the same species? while cutthroats and rainbows, which look almost identical and can breed and produce viable offspring, how it is that these are different species?
Could it be that scientists are arbitrary in determining the boundary between species? That in fact cutthroat and rainbows are the same species, by every measure that determines species?
http://en.wikipedia.org/wiki/Species
A species is often defined as the largest group of organisms capable of interbreeding and producing fertile offspring.
Under this definition, cutthroat and rainbows are sub-species.
I like to see different types of trout. I don’t want to see them all mixed into one type
“Protecting and maintaining the genetic integrity of native species is important for a species’ ability to be resilient and better adapt to a rapidly changing climate.”
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under this argument, human immigration should be outlawed to protect the “genetic integrity” of native humans.
“genetic integrity” has an ominous ring to it. Eugenics and the Master Race comes to mind. Along with mass sterilization and mass extermination.
Oh what a dangerous web we weave, when first we practice to deceive.
This is actually interesting. My tiny border stream has trout that some said were introduced brown trout released by the PA fisheries upstream. Then a MD natural resources website showed the tiny stream as a “brook trout” stream. Add to that introduced sunnies (bluegills) that compete w/the trout.
first, you change the definition of species…
…then you write this crap
Cuts and bows are breeding together. Just like they did before industrial revolution. The watersheds they were native to have changed a lot since the birth of the USA by human land use and human modification of the waterways.
Nice little fishes. I love the twitch of my strike indicator when one of them touches one of my soft-hackled nymphs that I lovingly tie in the winter months. : )
John
ferdberple says:
May 28, 2014 at 7:02 am
john says:
May 28, 2014 at 7:10 am
Well, apparently, the trout disagree with you. 8<) They DO like to see them all mixed into one type.
Latitude says:
May 28, 2014 at 7:22 am
Yeppers, it would be more accurate to call them different breeds of trout. But “that” would not be acceptable to the political types and their enviro “scientists” and activists.
Well, if the trout can interbreed successfully, and want to interbreed successfully, it's like that little-itty-bitty chiwowwow dog mating with the neighborhood mongrel mentioned earlier: The "scientists" are just going to get disappointed when their pristine and perfect "Nature" (gee, why do we capitalize God and Nature and Gaea the same, he asked whimsically ?) meets real life. And they find out that real life is not in a textbook nor a law book and a Code of Federal Regulations chapter and verse and line number. Now, what happened before when this kind of unacceptable behavior was found, the stream was sterilized and the “chosen fishes” were re-stocked at great expense with tremendous fervor .. from those who felt they were fulfilling their lives and their faith with ‘good works” ….
Species counts: New and threatened "species" are used nowadays to "CREATE" jobs and protected areas around "new species" (And, of course, discovering a "new species" or a newly threatened species is THE fastest way to get your name in the papers and in the textbooks. Fame, fortune, power, and honors and a "feeling" of having done something worthwhile! What's not to like? If there are no "threats" to isolated species there is no means in the law to increase restricted areas and no means to write new restrictions into old areas. In the courtroom, there is no restraint on lies, exaggerations, and "good intentions" of "protecting Nature". That capital letter that they worship, again. .
Harold says: “Aquatic miscegenation. Must preserve the purity of the trout races.”
Miscegenation worries would bring us full circle from Svante August Arrhenius and his “Racial Hygiene,” and back. How ironic.
So, climate change and evolution, both being around for billions of years and natural, is something to be alarmed about?
I string my own wedding rings and tie my hooks to leaders. They work great with bait on the hook but not so much without bait. The problem: Many rivers are designated artificial fly or lure, no real or artificial bait. Yet these rivers are sometimes not suitable for fly fishing (no pools, too fast/narrow, and lots of overhanging veg). So I’ve been thinking of adding a tied scented (attractor is okay) grasshopper to the hook, finishing with a flashy wedding ring, and using a sinker about 2 or 3 feet up for casting purposes. Feedback?
I think my wife would be upset iffen I went off and tied my wedding ring to a string and went around dunking it in the water trying to attract a smelly fish, but your wide might be different …. 8<)
Then again, I went and dropped melted steel on mine a few years back, and that wasn't so good either.
Whatsa “wide”?