Tag Archives: Invasive Species

Bad Ladybug

Different types of Harlequin ladybug, a rapidly spreading invasive pest. ©Entomart

Different types of Harlequin ladybug, a rapidly spreading invasive pest. ©Entomart

Ladybugs, once the championed protectors of backyard gardens, are showing spots of a less flattering color, and their public image looks like it could be taking an even bigger turn for the worse. A new study has found that invasive Harlequin ladybugs crossbreeding with a species of flightless ladybugs are creating a super strain of a buggy pest.

In recent years, ladybugs have taken their voracious appetites around the world, and they don’t just gobble up target insects. Couple this with plagues of ladybugs infesting homes, and you’ve got an unseemly problem on your hands.

To fight their spread, flightless ladybugs were released as a biological control agent. The idea being that the walk-only ladybugs wouldn’t spread as far as quick. Harlequin’s aren’t to be put off it would seem. The two types of ladybugs can hybridize, giving rise to offspring that are larger, faster-growing, and generally more robust than either of its parent species. Preliminary research suggests that the cross-bred young are even better-equipped to deal with starvation.

The findings by BenoÎt Facon of UMR Centre de Biologie et de Gestion des Populations in Cedex, France, and his colleagues are just a beginning. Researchers want to test multiple generations of hybrid and subject them to different conditions to unravel the magnitude of the Harlequin ladybug dilemma.

You can read more about their discoveries in the current issue of Evolutionary Applications.


Cane toads heart climate change

Cane Toad, AKA Bufo marinus, AKA troublemaker extraordinaire (Photo/ Eli Greenbaum)

Cane toads like it hot, and with climate change poised to raise temps in Australia, this persistent, invasive species could soon be living it up even more.

At least that’s the word coming out of new research from the University of Sydney and presented at the Society for Experimental Biology’s annual conference in Prague.

A lot of what we hear about climate change focuses on habitat loss (cue rising sea levels) or species extinction (sorry red wolf and coral reefs), but here’s another way the pesky, poisonous cane toad can flip the amphibian bird to mankind – warmer climes mean prolific times as far as the toad is concerned.

“The negative effect of high temperature does not operate in cane toads, meaning that toads will do very well with human induced global warming,” said Professor Frank Seebacher from the University of Sydney in a press release.

Many of you reading this are probably familiar with the story of the cane toad, but here’s the quick shake down. In the mid 1930s, Australian biologists, hoping to stem the onslaught of beetles ravaging cane fields, introduced cane toads to Queensland and the Northern Territory. Unfortunately, toads passed on the beetles, instead turning their appetites towards lizards, snakes and other native wildlife. To compound factors, the toads secrete a toxic substance that can do a serious number on just about anything that tries to eat it. So the cane fields now have beetles and bucket loads of poisonous toads. Sigh.

And because of research by Seebacher, we now have a good idea that toads are going to thrive even more as temperatures rise from climate change. Warmer weather makes for stronger, or at least more efficient, heart and lungs in the cane toad, Seebacher found. And if that’s not unsettling enough, the study also states “the cane toad can adapt its physiology in response to a changing environment repeatedly and completely reversibly many times during its lifetime.”

Will nothing temper their proliferation?

Before you totally throw up your hands and say, “Why do I read this if all you’re going to tell me is bad news,” here’s a ray, or sliver, of hope. Maybe, just maybe, this phenomenon will prove true for other toads, ones we actually would like to see stick around. I’ll get back to you when Seebacher conducts that study.


Saving snails: an invasive species becomes an unlikely hero

A land snail (Photo/ Petr Kratochvil)

Now, I know snails don’t come with the same poster-child charisma factor of more fuzzy, wide-eyed creatures  like pandas or baby tigers. But I hope you’ll imagine a tiny, high-pitched, “Help me!” issuing from the leaf litter at your feet, and stick with these little guys for a minute.

With that said, I’d like to tell you a story of a rat, a snail and a tree. They all live on the tiny island of Anijima, one of several in a chain of islands off the southeastern coast of Japan. The snail is critically endangered. The rat and tree are invasive species. You know those bullies of the natural world, the unwelcome visitors, the home wreckers of entire ecosystems. But before you go, “Oh here comes another invasive species story,” here’s the kicker – one of these encroachers, the tree, is actually in a sense the hero of this story, buying time for the snail and those trying to save it. The study, published online in the journal Conservation Biology, offers conservationists a new framework for restoring native ecosystems.

Anijima is part of the Ogasawara Island chain, a remote group of islands off Japan nominated for World Heritage listing. It’s also snail central. These islands are home to more than 100 species of land snail, 94 percent of which are endemic to those islands. Many of the snails have disappeared over the years, thanks in part to habitat loss and introduced predators.

Anijima was the exception. No one has lived there since the 1830s, and until recently, the environment looked much like it did 100 years ago. But a plant, the Casuarina tree has taken over the mid-western part of the island, converting natural forestland into a monoculture of dry coniferous forest. This delivered a significant blow to the land snails, as the snail’s home was turned into less ideal living quarters. Another blow came with the introduction of black rats in the 1930s. These voracious predators, gobble up the slow-movers, and since about 2006, have enjoyed an unprecedented population boom on the island, likely due to the eradication of goats – a competitor for food – and of feral cats – the rat’s main predator. In short, things weren’t looking good for the snails.

One might think, “Well, if you want to save the snails, just go in there and clear out the invasives.” But not all invasive species are created equal, and one scientist, Satoshi Chiba, with Tohuku University in Japan, has figured out that the Casuarina tree is actually helping the snail weather the rat boom.

Chiba looked specifically at the Ogasawarana genus of snails, a critically endangered group of snails considered a “natural monument” by the Japanese government. They are the only group of snails on the island still living on native vegetation on the island. Chiba surveyed plots in both Casuarina-laden habitat and native habitat, clearing sites of leaf litter, counting and identifying snail species and then returning everything to its place. Chiba also checked for rat carnage, and found that while initially, the tree causes a decline in snail populations, once the rat population went crazy, the Casuarina tree actually provided the snail with a better refuge from the predator than the snail’s native habitat.

The ground litter in the Casuarina habitat is deeper and denser than the snails’ natural environment. Black rats like to forage at the surface, and thus, the snails stand a better chance of avoiding a rat’s tooth and claw in the debris of a Casuarina forest.

The lesson here is not that an invasive species is necessarily good, but that there is an order to things when it comes to restoring an environment impacted by multiple non-native species. For Anijima Island, and the Ogasawarana snails, if they are to be saved, it’s likely that the black rats need to go before the invasive trees.

So, do you care a little more about a tiny mollusk? I don’t know, but at the very least, the story has a rich history, and just think how many other species suffering from a similar tale this study could help.


Reclamation, restoration and mountaintop removal

My first taste of reclamation came as a grad student while on a fieldtrip along Colorado’s “Uranium Highway.” We stopped in the ghost town of Uravan, a former Uranium/Vanadium boomtown. And except for a couple buildings, everything had been torn down, the tailings ponds evaporated, land reclaimed or in the process of being so. It was then that I learned that reclamation and restoration were not the same thing. Above the once upon town sat tailings sites. Instead of a rust-colored desert environment,  meticulous patterns of white and black rock zig-zagged across the hilltop, laid out like some sort of interpretive landscape project.

Reclamation, I thought, was supposed to help clean up after we’d finished using the land. It was supposed to help return the land to itself. I’ve seen many reclaimed sites since that fieldtrip, and have yet to come across one that resembled nature’s design.

That’s not to say that reclamation is a lost cause or a sham, just that it can be better. Now scientists are trying to help make that happen with arguably one of the most destructive and controversial mining practices at work today, mountaintop removal. Sarah Hall, of Kentucky State University,  and her colleagues Christopher Barton and Carol Baskin, of the University of Kentucky, have discovered a new method of replanting mined Appalachian sites, one that gives native landscapes a leg up at renewal. (You can find their study in the online early edition of Restoration Ecology)

Mountaintop removal reclamation projects often involve planting blasted and terraced mountainsides with non-native grasses. (Early surface mine reclamation would sometimes simply abandoned the site.) Perhaps one of the more unexpected outcomes of reclamation comes from Mingo County, W. Va., where reclamation turned a blast site into what’s now known as the Twisted Gun Golf Course.

Rather than seeding mined areas with grasses, which tend to stunt recovery of native species, Hall sought to test the possibility of replanting mountaintop removal sites with the trees and forbs kin to the forests that had existed before the mines. Hall’s idea seems in hindsight to be quite obvious. Put back the original topsoil scraped away when creating the mine. This soil she found was rich with the seeds and microbial recipe that could help re-establish forest. Where Hall and her team tried the method, the plants started to grow, including arrow-leaved asters, Virginia pines and blueberry.

The method is not enough to completely recover the forest, but it’s a start, and a step up from the grassy slopes that have come to replace so many of Appalachia’s mined mountainsides. Hall’s research highlights a two-fold lesson  – we need to recognize that reclamation is not restoration, and there are practical ways to make reclamation better. Then maybe these environments that have given us so much of their riches at least have a chance to return to themselves, even if it’s just a little.


Woe betide the lovesick lamprey

Love is in the water, and the lamprey swears she’s found her match. She swims the corner ready to score. That’s when they spring the trap. 

Scientists out of Michigan State University are using chemical trickery to seduce and capture female sea lampreys, a devastatingly invasive species found in the Great Lakes. A single lamprey can eat up to 40 pounds of fish, and they’re to blame for the extinction of at least three whitefish species.  The voracious predators have proven difficult and expensive to control, costing the U.S. and Canadian governments $10 to $15 million a year.

But males it turns out, release an irresistible chemical into the water attracting females from more than a hundred meters away, and this mojo might just be the key to the lamprey’s undoing.  Weiming Li, a professor of fisheries and wildlife at MSU, and his team spent years isolating and synthesizing a fake version of sea lamprey love potion. Now they’ve landed on a treatment that is as effective as the lamprey’s own and when used in small doses could effectively treat sea lamprey infested waters. 

“The commission considers regulating spawning and migrating behavior with pheromones the most promising control method for implementation,” Li said in a press release. “So we’re excited about the possibilities.”

You can learn more about this promising new treatment method in the latest version of the Proceedings of the National Academy of Sciences.


Tea for the common beetle infestation

The terror of lodgepole pine forests across the west may face the ultimate KO thanks to a commonly used ingredient of herbal tea. As if to add the final insult, this anti-beetle ingredient originates from the offending mountain beetles themselves. When a beetle suspects too many of its kind moving into the neighborhood, it releases a chemical telling others to stay away. The message is so strong, beetle numbers dropped three-fold in treated areas. Now scientists have figured out how to apply the natural repellent over thousands of acres of infected forest by dropping chemically-laced flakes out of a plane.

Nancy Gillette, a Forest Service scientist at the Pacific Southwest Research Station, thought of the idea to release the flakes by air and has already used the method to treat two areas around in the West, Mount Shasta and portions of Idaho’s Bitterroot Mountains. Where they dropped flakes, beetle infestations fell to 30 percent. Now her research team is looking into upping the environmental friendliness of the treatment by creating a biodegradable version.

Point one for naturopathic beetle treatments.


An upside to climate change?

They’re the five “dirty words” of the West — cheatgrass; spotted knapweed; yellow starthistle; tamarisk; and leafy spurge — but the battle against these pervasive troublemakers could receive a boost from an unlikely ally, climate change. Scientists from Princeton University have determined that climate change will very likely cause massive die-offs of these invasive plants across the West, creating unprecedented opportunities to restore millions of acres of infected wilderness to native vegetation.

The findings, released this month in the journal Global Change Biology, will help land managers develop long-term invasive plant recovery projects. The restorative potential comes at a price however, as the model used in the study also predicts that some populations of invasive plants may simply shift their ranges to new areas — yellow starthistle will likely move from its current range in California, Oregon and Washington to a new ranges in California and Nevada for example.

Either way, the study forecasts a new picture of the western landscape, and may help researchers treat or possibly prevent invasive plant infestations. Whether the prognosis is good or bad, this is potentially important news for land managers and residents.


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