In the past 100 years, the planet has warmed in the range of 10 times faster than it did on average over the past 5,000. In response, thousands of species are traveling poleward, climbing to higher elevations, and diving deeper into the seas, seeking their preferred environmental conditions. This great migration is challenging traditional ideas about native species, the role of conservation biology and what kind of environment is desirable for the future.
In a 2017 review for Science, University of Tasmania marine ecology professor Gretta Pecl and colleagues wrote, "[C]limate change is impelling a universal redistribution of life on Earth. For marine, freshwater, and terrestrial species alike, the first response to changing climate is often a shift in location." In fact, Pecl says, data suggest that at least 25% and perhaps as much as 85% of Earth's estimated 8.7 million species are already shifting ranges in response to climate change.
But when they arrive, will they be welcome? Traditional definitions classify species according to place. "Native" species arrived without human help and usually before widespread human colonization, so are likely to have natural predators and are unlikely to go rogue. Non-natives are newcomers and suspect. Though 90% cause no lasting damage, 10% become invasive — meaning that they harm the environment, the economy or human health. Last year a multinational report flagged invasive species as a key driver of Earth's biodiversity crisis.
Known and anticipated changes in species distribution due to climate change around the world have implications for culture, society ecosystems, governance and climate change. Figure used with permission from Gretta T. Pecl, originally published on 31 Mar 2017 in Science 355(6332).
How we define species is critical, because these definitions influence perceptions, policy and management. The U.S. National Invasive Species Council (NISC) defines a biological invasion as "the process by which non-native species breach biogeographical barriers and extend their range" and states that "preventing the introduction of potentially harmful organisms is … the first line of defense." But some say excluding newcomers is myopic.
"If you were trying to maintain the status quo, so every time a new species comes in, you chuck it out," says Camille Parmesan, director of the French National Centre for Scientific Research, you could gradually "lose so many that that ecosystem will lose its coherence." If climate change is driving native species extinct, she says, "you need to allow new ones coming in to take over those same functions."
As University of Florida conservation ecologist Brett Scheffers and Pecl warned in a 2019 paper in Nature Climate Change, "past management of redistributed species … has yielded mixed actions and results." They concluded that "we cannot leave the fate of biodiversity critical to human survival to be randomly persecuted, protected or ignored."
Existing Tools
One approach to managing these climate-driven habitat shifts, suggested by University of California, Irvine marine ecologist Piper Wallingford and colleagues in a recent issue of Nature Climate Change, is for scientists to adapt existing tools like the Environmental Impact Classification of Alien Taxa (EICAT) to assess potential risks associated with moving species. Because range-shifting species pose impacts to communities similar to those of species introduced by humans, the authors argue, new management strategies are unnecessary, and each new arrival can be evaluated on a case-by-case basis.
Karen Lips, a professor of biology at University of Maryland who was not associated with the study, echoes the idea that each case is so varied and nuanced that trying to fit climate shifting species into a single category with broad management goals may be impractical. "Things may be fine today, but add a new mosquito vector or add a new tick or a new disease, and all of a sudden things spiral out of control," she says. "The nuance means that the answer to any particular problem might be pretty different."
In recent years, northern flying squirrels in Canada have found themselves in the company of new neighbors — southern flying squirrels expanding their range as the climate warms. Public Domain / USFW
Laura Meyerson, a professor in the Department of Natural Resources Science at the University of Rhode Island says scientists should use existing tools to identify and address invasive species to deal with climate-shifting species. "I would like to operate under the precautionary principle and then reevaluate as things shift. You're sort of shifting one piece in this machinery; as you insert a new species into a system, everything is going to respond," she says. "Will some of the species that are expanding their ranges because of climate change become problematic? Perhaps they might."
The reality is that some climate-shifting species may be harmful to some conservation or economic goals while being helpful to others. While sport fisherman are excited about red snapper moving down the East Coast of Australia, for example, if they eat juvenile lobsters in Tasmania they could harm this environmentally and economically important crustacean. "At the end of the day … you're going to have to look at whether that range expansion has some sort of impact and presumably be more concerned about the negative impacts," says NISC executive director Stas Burgiel. "Many of the [risk assessment] tools we have are set up to look at negative impact." As a result, positive effects may be deemphasized or overlooked. "So that notion of cost versus benefit … I don't think it has played out in this particular context."
Location, Location, Location
In a companion paper to Wallingford's, University of Connecticut ecology and evolutionary biology associate professor Mark Urban stressed key differences between invasive species, which are both non-native and harmful, and what he calls "climate tracking species." Whereas invasive species originate from places very unlike the communities they overtake, he says, climate tracking species expand from largely similar environments, seeking to follow preferred conditions as these environments move. For example, an American pika may relocate to a higher mountain elevation, or a marbled salamander might expand its New England range northward to seek cooler temperatures, but these new locations are not drastically different than the places they had called home before.
Climate tracking species may move faster than their competitors at first, Urban says, but competing species will likely catch up. "Applying perspectives from invasion biology to climate-tracking species … arbitrarily chooses local winners over colonizing losers," he writes.
The marbled salamander, a native of the eastern U.S., is among species whose range could expand northward to accommodate rising temperatures. Seánín Óg / Flickr / CC BY-NC-ND 2.0
Urban stresses that if people prevent range shifts, some climate-tracking species may have nowhere to go. He suggests that humans should even facilitate movement as the planet warms. "The goal in this crazy warming world is to keep everything alive. But it may not be in the same place," Urban says.
Parmesan echoes Urban, emphasizing it's the distance that makes the difference. "[Invasives] come from a different continent or a different ocean. You're having these enormous trans-global movements and that's what ends up causing the species that's exotic to be invasive," she says. "Things moving around with climate change is a few hundred miles. Invasive species are moving a few thousand miles."
In 2019 University of Vienna conservation biology associate professor Franz Essl published a similar argument for species classification beyond the native/non-native dichotomy. Essl uses "neonatives" to refer to species that have expanded outside their native areas and established populations because of climate change but not direct human agency. He argues that these species should be considered as native in their new range.
They Never Come Alone
Meyerson calls for caution. "I don't think we should be introducing species" into ecosystems, she says. "I mean, they never come alone. They bring all their friends, their microflora, and maybe parasites and things clinging to their roots or their leaves. … It's like bringing some mattress off the street into your house."
Burgiel warns that labeling can have unintended consequences. We in the invasive species field … focus on non-native species that cause harm," he says. "Some people think that anything that's not native is invasive, which isn't necessarily the case." Because resources are limited and land management and conservation are publicly funded, Burgiel says, it is critical that the public understands how the decisions are being made.
Piero Genovesi, chair of the International Union for the Conservation of Nature's Invasive Species Specialist Group, sees the debate about classification — and therefore about management — as a potential distraction from more pressing conservation issues.
"The real bulk of conservation is that we want to focus on the narrow proportion of alien species that are really harmful," he says. In Hawaii "we don't discuss species that are there [but aren't] causing any problem because we don't even have the energy for dealing with them all. And I can tell you, no one wants to remove [non-native] cypresses from Tuscany. So, I think that some of the discussions are probably not so real in the work that we do in conservation."
Indigenous frameworks offer another way to look at species searching for a new home in the face of climate change. According to a study published in Sustainability Science in 2018 by Dartmouth Native American studies and environmental studies associate professor Nicholas Reo, a citizen of the Sault Ste. Marie Tribe of Chippewa Indians, and Dartmouth anthropology associate professor Laura Ogden, some Anishnaabe people view plants as persons and the arrival of new plants as a natural form of migration, which is not inherently good or bad. They may seek to discover the purpose of new species, at times with animals as their teachers. In their paper Reo and Ogden quote Anishnaabe tribal chairman Aaron Payment as saying, "We are an extension of our natural environment; we're not separate from it."
The Need for Collaboration
The successful conservation of Earth's species in a way that keeps biodiversity functional and healthy will likely depend on collaboration. Without global agreements, one can envision scenarios in which countries try to impede high-value species from moving beyond their borders, or newly arriving species are quickly overharvested.
In Nature Climate Change, Sheffers and Pecl call for a Climate Change Redistribution Treaty that would recognize species redistribution beyond political boundaries and establish governance to deal with it. Treaties already in place, such as the Convention on International Trade in Endangered Species of Wild Fauna and Flora, which regulates trade in wild plants and animals; the Migratory Bird Treaty Act; and the Agreed Measures for the Conservation of Antarctic Fauna and Flora, can help guide these new agreements.
"We are living through the greatest redistribution of life on Earth for … potentially hundreds of thousands of years, so we definitely need to think about how we want to manage that," Pecl says.
Genovesi agrees that conservationists need a vision for the future. "What we do is more to be reactive [to known threats]. … It's so simple to say that destroying the Amazon is probably not a good idea that you don't need to think of a step ahead of that." But, he adds, "I don't think we have a real answer in terms of okay, this is a threshold of species, or this is the temporal line where we should aim to." Defining a vision for what success would look like, Genovesi says, "is a question that hasn't been addressed enough by science and by decision makers."
At the heart of these questions are values. "All of these perceptions around what's good and what's bad, all [are based on] some kind of value system," Pecl says. "As a whole society, we haven't talked about what we value and who gets to say what's of value and what isn't."
This is especially important when it comes to marginalized voices, and Pecl says she is concerned because she doesn't "think we have enough consideration or representation of Indigenous worldviews." Reo and colleagues wrote in American Indian Quarterly in 2017 that climate change literature and media coverage tend to portray native people as vulnerable and without agency. Yet, says Pecl, "The regions of the world where [biodiversity and ecosystems] are either not declining or are declining at a much slower rate are Indigenous controlled" — suggesting that Indigenous people have potentially managed species more effectively in the past, and may be able to manage changing species distributions in a way that could be informative to others working on these issues.
Meanwhile, researchers such as Lips see species classification as native or other as stemming from a perspective that there is a better environmental time and place to return to. "There is no pristine, there's no way to go back," says Lips. "The entire world is always very dynamic and changing. And I think it's a better idea to consider just simply what is it that we do want, and let's work on that."
Reposted with permission from Ensia.
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The company sells a range of eco-friendly items like leggings, rash guards, and board shorts that are made using recycled post-consumer plastic bottles. There are currently 16 causes represented by distinct marine-life patterns, from whale shark research and invasive lionfish removal to sockeye salmon monitoring and abalone restoration.
One such organization is Get Inspired, a nonprofit that specializes in ocean restoration and environmental education. Get Inspired founder, marine biologist Nancy Caruso, says supporting on-the-ground efforts is one thing that sets Waterlust apart, like their apparel line that supports Get Inspired abalone restoration programs.
"All of us [conservation partners] are doing something," Caruso said. "We're not putting up exhibits and talking about it — although that is important — we're in the field."
Waterlust not only helps its conservation partners financially so they can continue their important work. It also helps them get the word out about what they're doing, whether that's through social media spotlights, photo and video projects, or the informative note card that comes with each piece of apparel.
"They're doing their part for sure, pushing the information out across all of their channels, and I think that's what makes them so interesting," Caruso said.
And then there are the clothes, which speak for themselves.
Advocate Apparel to Start Conversations About Conservation
Waterlust's concept of "advocate apparel" encourages people to see getting dressed every day as an opportunity to not only express their individuality and style, but also to advance the conversation around marine science. By infusing science into clothing, people can visually represent species and ecosystems in need of advocacy — something that, more often than not, leads to a teaching moment.
"When people wear Waterlust gear, it's just a matter of time before somebody asks them about the bright, funky designs," said Waterlust's CEO, Patrick Rynne. "That moment is incredibly special, because it creates an intimate opportunity for the wearer to share what they've learned with another."
The idea for the company came to Rynne when he was a Ph.D. student in marine science.
"I was surrounded by incredible people that were discovering fascinating things but noticed that often their work wasn't reaching the general public in creative and engaging ways," he said. "That seemed like a missed opportunity with big implications."
Waterlust initially focused on conventional media, like film and photography, to promote ocean science, but the team quickly realized engagement on social media didn't translate to action or even knowledge sharing offscreen.
Rynne also saw the "in one ear, out the other" issue in the classroom — if students didn't repeatedly engage with the topics they learned, they'd quickly forget them.
"We decided that if we truly wanted to achieve our goal of bringing science into people's lives and have it stick, it would need to be through a process that is frequently repeated, fun, and functional," Rynne said. "That's when we thought about clothing."
Support Marine Research and Sustainability in Style
To date, Waterlust has sold tens of thousands of pieces of apparel in over 100 countries, and the interactions its products have sparked have had clear implications for furthering science communication.
For Caruso alone, it's led to opportunities to share her abalone restoration methods with communities far and wide.
"It moves my small little world of what I'm doing here in Orange County, California, across the entire globe," she said. "That's one of the beautiful things about our partnership."
Check out all of the different eco-conscious apparel options available from Waterlust to help promote ocean conservation.
Melissa Smith is an avid writer, scuba diver, backpacker, and all-around outdoor enthusiast. She graduated from the University of Florida with degrees in journalism and sustainable studies. Before joining EcoWatch, Melissa worked as the managing editor of Scuba Diving magazine and the communications manager of The Ocean Agency, a non-profit that's featured in the Emmy award-winning documentary Chasing Coral.
First you need a helicopter capable of reaching sites more than 4,600 feet above sea level.
Then you need exactly the right weather to fly — and the hope that conditions don't shift, as they frequently do.
"The weather's not that great," said Raine, the project coordinator for the Kaua'i Endangered Seabird Recovery Project. "We keep going and hanging out at the helipad, waiting and watching. And then it looks like it's going to be okay but it gets fogged in, or you get up there and then you get stuck. The joys of working in a remote, inaccessible area."
The seabirds — including Newell's shearwaters (Puffinus newelli) and Hawaiian petrels (Pterodroma sandwichensis) — obviously have a much easier time getting up the tops of these mountains.
Raine holding a Hawaiian petrel chick. Courtesy Kaua'i Endangered Seabird Recovery Project
So, unfortunately, do several species of invasive predators — including feral cats, black rats and feral pigs — that have put these ground-nesting birds, and so many other native Hawaiian species, on the fast track toward extinction.
"People are always really surprised by this," Raine said, "but it doesn't matter how remote the area, or how apparently inhospitable it is to predators like cats. You're going to find cats and rats and pigs in these areas. There wasn't a single site that we work in that doesn't have all these predators, busy eating the birds."
An endangered chick in the mouth of a feral cat. Courtesy Kaua'i Endangered Seabird Recovery Project
Like many island endemics, Hawaii's bird species grew up without mammalian predators, so they're ill-adapted to the teeth and claws that arrived with human society. The cats descended from housecats, while pigs escape from agricultural sites and rats descended from stowaways on ships.
That's why the Kaua'i Endangered Seabird Recovery Project has spent the past nine years constructing fences and establishing other predator controls — work that is proving essential in giving these native birds a chance.
The first step in controlling predators is quantifying the threat.
According to a paper Raine and his colleagues published earlier this year in The Journal of Wildlife Management, introduced predators killed at least 309 endangered seabirds at six monitored breeding colonies between 2011 and 2017. That's quite a blow for each of these endangered species.
"Newell's shearwaters and Hawaiian petrels have suffered catastrophic declines over the last few decades," Raine said. "Any chick that's lost in the population is one that we can't afford to lose."
Hawaiian petrel. © Ken Chamberlain, some rights reserved (CC-BY-NC). Via iNaturalist.
The researchers took on the sad task of collecting the dead and examining the wound patterns to determine which type of predator made the kill.
Rats, it turned out, killed the most — more than 50% of mortalities — usually from entering the birds' rocky burrows and eating eggs and chicks. That dramatically slows recovery efforts, but the research shows that adult birds who've lost their chicks returned to the same burrows the following year to try again.
Pigs kill fewer birds — about 10% of all tracked mortalities — but they were the most destructive, digging up and taking out entire nests. "It's literally like someone's taken a hand grenade and stuffed it down the burrow and blown it up," Raine said. "They just eat whatever's inside."
Cats were responsible for another 35% of known deaths, and Raine says the research shows those mortalities were the worst for the long-term health of the bird species. Cats target breeding birds, taking out not just the current generation but any hope of successive generations. The seabirds are very faithful to both their burrow sites and their mates, so if a cat takes out one parent the other might not breed again for several years, if at all. (Without predation, the researchers say an amazing 98.6% percent of breeding pairs matched up again and bred each year of the study.)
And while cats in general are the most destructive, some individual cats are downright scary.
"Every now and then, you get a sort of super cat, which is really good at finding burrows and killing the birds," he said.
In one incident recounted in the paper, the seabird recovery team found images of a cat taken by nine out of 30 remote cameras on the same day. Each camera was trained at a different seabird burrow — which provided ready meals for the feral feline.
"It just shows that all you need is for a cat to get into an area for a very short period," Raine said. "When the birds are sitting in a hole in the ground, they're entirely vulnerable to predation. The cat can very easily wipe out a huge number of birds."
Raine describes another incident as "quite horrific to watch." It took place at a remote site the team can only visit about once a month during breeding season, "because it's expensive and hard to get to," he said. They arrived one day to review the site's automatic cameras and the images revealed "this one cat just wreaking havoc across the site. It goes in and kills an adult Newell's shearwater, and they next thing you know it's emerging from the same burrow with four kittens. So it uses that burrow to raise the kittens, and then we get it on camera at another burrow with the kittens, basically training them how to kill more shearwaters."
That's a tough thing to see — especially when these researchers have followed the comings and goings at these burrows for years.
"You start to really empathize with these birds, because you're watching them on the burrow cameras and you're seeing all these amazing behaviors," Raine said. "And we're tracking them as well. We're seeing that they make these incredible journeys to feed their chicks. Hawaiian petrels go towards the coast of Alaska, 11-14,000 kilometers on a feeding voyage, and then you go to the site and you find this bird that's just been shredded by an introduced predator and the chicks left to starve to death. It's quite hard to deal with."
But as difficult and dangerous as these predators can be, the research also shows that the situation is far from hopeless.
Fence Me In
Over the past decade, the Kaua'i Endangered Seabird Recovery Project and its many organizational partners have concentrated on establishing predator controls at six of their seven regularly monitored seabird breeding sites.
Again, this isn't easy to accomplish in these remote, rarely visited locations. Materials must be flown in, ungulate-proof fences built, other traps set, and pig-hunting expeditions organized. All of it must be accomplished and maintained in precarious territory full of wet vegetation, narrow ridgelines and steep canyon walls.
To make things even more difficult, the human visitors must leave the habitat as undisturbed as possible.
"If you start making trails in these areas, then you're basically just opening them up to the hordes of predators that are out there," Raine says.
But the hard work pays off.
According to the paper, fences and other controls not only keep the invasive predators out, they give the birds the opportunity to thrive.
The research team used seven years data from the six sites, from before and after predator controls were established, and projected striking results for the future of the two seabird species.
The first model looked at what would happen to each site without predator controls. It was a disaster — mostly due to cats. "We ran that for 50 years, and we found that all of the colonies dwindle toward extinction."
The paper, in what Raine acknowledges as gallows humor, calls this the CATastrophe model.
The second modeling approach incorporated data from successful breeding that took place after more extensive predator controls (fences and traps) were put in place. "We found that the populations increased over those 50 years," Raine said. Under the model, which was based on 2017 population growth rates at sites with predator controls, most sites would see a 50-60% increase over the 50-year projection, while one site more than doubled.
"It really does show that if you remove the predators, the birds will begin to recover."
This isn't the be all and end all. Hawaiian seabirds face a laundry list of additional threats, including climate change, collisions with power lines, reduced fish populations at sea, and invasive plants that change forest compositions. The models don't address those threats, which also require mitigation.
There's also another introduced predator: barn owls. Hawaii introduced barn owls in the 1960s to control rats, but — as we've seen in so many other similar examples — they quickly became a new problem. Owls only killed 12 seabirds during the study, but Raine says these newest invaders pose an increasing threat that's proven harder to control. You can build fences to protect birds, after all, but you can't prevent other birds from flying over those protections.
But this research does prove that current management techniques to protect Hawaiian seabirds from their most pressing threats — cats, rats and pigs — really do work, and that they can be applied to more locations, even by private landowners who have birds on their properties. "Although we've got seven managed sites, there are other sites on the island where the birds are still hanging on, and there's no reason to expect that these techniques wouldn't be effective at other colonies."
That's important, because some of those additional sites are on the edge.
"We're finding that these other sites are just going silent," Raine said. "With no management on them, the birds just flit away." The paper recommends predator-proof fences at all sites, as well as dedicated year-round funding for both seabird monitoring efforts and predator-control operations designed to specifically target the composition of animals at each location. The authors also suggest additional port biosecurity to prevent more invasive species from arriving, and possibly the targeted use of landscape-level toxicants to remove rats and cats.
In addition, Raine says, these techniques can be applied to other species and other island locations where invasive predators threaten ground-nesting birds.
Perhaps most importantly, the research helps show these conservationists — whose work has continued as "essential" during the pandemic — that their efforts to fight extinction in these challenging, hard-to-reach habitats are paying off.
"I remember one of our sites in particular — in fact the one I was trying to get into today — the first time I went there I found within a five-foot area a burrow that had been predated by a cat, a dead chick that had been pulled out by a rat, and a burrow that had been destroyed by a pig," Raine recounted. "Now you can go a month without even seeing predators at some of these sites because of the great work that the controllers' crews are doing."
And this raises one more issue: this work isn't just about birds. It may help heal Hawaii — the extinction capital of the world — in the process.
"I think it's really important that people understand the critical importance of seabirds as the architects of the island itself," Raine said. "They bring all those ocean nutrients up into the mountains, and their partly responsible for the watersheds that we all rely on. It's a whole ecosystem that needs to be addressed."
Reposted with permission from The Revelator.
All in all, it's a small patch of heaven—exactly what you'd expect from a southwestern Pennsylvanian forest.
Except, that is, for the crazy snake worms.
Named for the way they writhe and leap off the ground like snakes on a hot plate, crazy snake worms are an invasive species on the move through the eastern half of the country. Originally from Korea and Japan, these annelids are thought to have arrived in the U.S. 50-some years ago as stowaways in the pots of decorative plants. Since then, crazy snake worms have spread out across Vermont, New Hampshire, New York, Delaware, Maryland, Illinois, Wisconsin, Alabama, Georgia, Texas, Oklahoma, Louisiana and other states.
And my backyard.
Take a step into my woods in August or September, after the worms have spent the summer growing to half a foot long, and you can watch as scores of them suddenly emerge from beneath your foot and the surrounding leaf litter. Try to pick one up and it'll leap from your hand like a fish out of water. Sometimes the things even leave their tails behind—a behavior meant to fool predators.
Gross, sure, but are they really crazy? Yes, yes, they are. As a kid, I remember going digging for earthworms, the more standard variety, to use as fishing bait. But crazy snake worms—they find you.
Whereas some worm species like to burrow down deep, these worms conspicuously wriggle around the uppermost layer of soil, spending all day sliding through the leaf litter and munching on organic material. And there's the real problem.
Gardeners love earthworms because they "churn up the soil and create spaces for nutrients to flow and water to get to the roots," said Bradley Herrick, an ecologist at the University of Wisconsin–Madison Arboretum. But it's not always that simple. Crazy snake worms also cycle nutrients, said Herrick, but they do it so quickly and so superficially—aboveground, not below—that erosion and rain often wash away all the good stuff before the plants can make use of it. This is especially problematic for ecosystems in areas of the Northeast and upper Midwest, where glaciers once scoured the land. For tens of thousands of years, forests there evolved in the absence of worms.
"Those glaciers basically exterminated all the earthworms, and so all the earthworms that are found now in that part of the country are all nonnative and mostly invasive in nature," said Herrick. You read that right. Not only are crazy snake worms nonnative, but every other worm you've ever seen in these regions is, too.
Most of us don't spend a lot of time thinking about the importance of dirt—especially not forest dirt—but worms can be proficient ecosystem engineers, and they are transforming the earth beneath us. Their "poop," called castings, contains calcium carbonate, and in great enough amounts it can change the chemistry of the soil, making it more alkaline and less welcoming to certain kinds of plants, such as azaleas and oaks.
Native wildlife species take a hit from the activity of crazy snake worms, too. Seedlings and wildflowers have a tough time taking root in the depleted, dry, and loose soil the worms create. The resulting absence of vegetation can not only exacerbate erosion but also rob ground-nesting birds, salamanders, and insects of hiding places. And in the Great Smoky Mountains of eastern Tennessee, researchers have found lower millipede biodiversity and numbers wherever crazy snake worms crawl. They think the worms may be outcompeting millipedes for food or simply changing the ecosystem in such a way that it no longer supports the thousand-leggers.
While research on crazy snake worms is scant, some interesting facts have begun to surface. For example, what we refer to as crazy snake worms are actually three different but closely related species: Amynthas agrestis, Amynthas tokioensis and Metaphire hilgendorfi. And where one species occurs, you often find the second and third, too. So the invasion is a bit of a worm party.
Amynthas hilgendorfi eats so voraciously that it can grow at a rate of 1.35 milligrams per day. (For those of you unfamiliar with standard worm growth rates, that's nearly seven times as fast as the nightcrawler, Lumbricus terrestris.) Add to this the fact that crazy snake worms are parthenogenic, which basically means even their unfertilized eggs can hatch (so they can reproduce without having to find a mate), and you've got the makings of a truly intractable critter.
"Just at the small scale we have here at the Arboretum, in some of our maple woodlands they've spread as much as 20 to 25 acres in four years," said Herrick.
This worm party invites other nonnative species to the forest, too. The native vegetation void the worms cause on the forest floor allows hardy invasive species like buckthorn and garlic mustard to take root. Herrick refers to the process as a feedback loop, adding, "It can turn into a kind of parade of invasive species once that first disturbance is there."
This may explain the excessive amount of stiltgrass in my own woods. This invasive weed chokes out wildflowers and other natives while altering the soil's moisture and pH content—more transformations to which native species will have to adjust.
When it comes to biological invasions, prevention is the best medicine. For crazy snake worms, this means cleaning gardening tools and boots before taking them to worm-free areas. (The worms themselves are unlikely to hitchhike on your person, but their egg cocoons are tiny and can travel in dirt and mud.) Herrick said finding reliable suppliers for mulch, soil and plants is also key.
But there isn't much we can do currently about existing infestations. There are no approved pesticides for worms (and spraying every inch of forest is out of the question in any event). The egg casings of crazy snake worms are also capable of surviving temperatures as low as –12 degrees Fahrenheit. So even a big, bad polar vortex, like the one that hit recently, wouldn't necessarily put a dent in my woods' worm problem.
So, can we kill it with fire, as the Internet would say? Well, yes and no. A 2015 study found that prescribed burns don't effectively kill off many adult worms—though they did reduce the number of cocoons that hatched later. Fire, the researchers suggest, might also indirectly kill many surviving hatchlings simply by burning up the soil nutrients they rely on for food.
Good to know, but I imagine my neighbors would have some issues with me setting our adjoining woods ablaze in order to slightly reduce the survival rate of juvenile worms. So, unless another glacier scrapes into town, my crazies are here to stay.
Reposted with permission from our media associate onEarth.
As the female population has declined to the point where there is only one female for every three male parrots, the excess males have begun to bother already-paired females for sex, distracting both parents from mating and raising young. In a study published in The Journal of Animal Ecology on Monday, researchers at Australian National University (ANU) found that more than half of swift parrot nests now had babies from more than one father.
"This is remarkable for parrots because most species are monogamous," lead researcher Prof. Rob Heinsohn said in an ANU press release.
In Tasmania it's breeding time for the critically endangered swift parrot — but something is very wrong ... https://t.co/1K8TsxRDBV— ABC Hobart (@ABC Hobart)1543994193.0
The shared parenting isn't working out for the babies, however. While equal numbers of eggs are being laid, fewer are living to leave the nest, Heinsohn told The Guardian. That's because the breeding male parrot ends up spending all his time fighting off unattached males and the female spends her time dealing with the harassment and sneaking sex with the interlopers.
"We think the females are having sex with the other males for a range of reasons, but probably the main one is just to get them off their backs," Heinsohn said in the press release.
Both parents have less time, then, to gather food for their offspring.
"Although most population decline was directly attributable to sugar gliders killing nesting females, the impact of conflict and lower success from shared mating reduced the population by a further five percent," Heinsohn said in the press release.
The researchers calculated that if the lowest observed rate of shared paternity persisted for three generations, the birds' population would decline by 89.4 percent.
Sugar gliders are an especial threat to female parrots because they can enter hollow nests and kill females while they are incubating their eggs there. They kill off more than half of the female swift parrots in Tasmania every year.
Study co-author Dejan Stojanovic told The Guardian that scientists were working with the Tasmanian government to control the sugar glider population and installing nesting-boxes for the parrots that lock when the sun sets at night, but nothing had been done about deforestation.
"I am not confident at all [that the species will survive]," Stojanovic told The Guardian. "We have been working on swift parrots for the last decade, we know so much about them, even to the point that we know about their sex lives now … but even though we know so much, we are actively logging their habitat. We are wilfully pushing the things that are going to lead to their extinction."