By Jenny Morber
Caribbean corals sprout off Texas. Pacific salmon tour the Canadian Arctic. Peruvian lowland birds nest at higher elevations.
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).<p>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.</p><p>"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."</p><p>As University of Florida conservation ecologist Brett Scheffers and Pecl warned in a <a href="https://www.nature.com/articles/s41558-019-0526-5" target="_blank">2019 paper in <em>Nature Climate Change</em></a>, "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."</p>
Existing Tools<p>One approach to managing these climate-driven habitat shifts, suggested by University of California, Irvine marine ecologist Piper Wallingford and colleagues in <a href="https://www.nature.com/articles/s41558-020-0768-2" target="_blank">a recent issue of Nature Climate Change</a>, is for scientists to adapt existing tools like the <a href="https://www.iucn.org/theme/species/our-work/invasive-species/eicat" target="_blank">Environmental Impact Classification of Alien Taxa (EICAT)</a> 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.</p><p>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."</p>
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<p>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."</p><p>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."</p>
Location, Location, Location<p>In a <a href="https://www-nature-com.ezp3.lib.umn.edu/articles/s41558-020-0770-8" target="_blank">companion paper</a> 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.</p><p>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.</p>
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<p>Urban stresses that if people prevent range shifts, some climate-tracking species may have nowhere to go. He suggests that humans should even <a href="https://ensia.com/features/time-for-trees-to-pack-their-trunks/" target="_blank">facilitate movement</a> 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.</p><p>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."</p><p>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.</p>
They Never Come Alone<p>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."</p><p>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.</p><p>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.</p><p>"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."</p><p>Indigenous frameworks offer another way to look at species searching for a new home in the face of climate change. According to <a href="https://link.springer.com/article/10.1007%2Fs11625-018-0571-4" target="_blank">a study</a> 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."</p>
The Need for Collaboration<p>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.</p><p>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.</p><p>"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.</p><p>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."</p><p>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."</p><p>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 <a href="https://cpb-us-e1.wpmucdn.com/sites.dartmouth.edu/dist/9/52/files/2012/10/Reo_etal_AIQ_invasive_species_2017.pdf" target="_blank">wrote in American Indian Quarterly in 2017</a> 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.</p><p>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."</p>
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By John R. Platt
It takes a lot of effort and more than a little bit of luck for researchers like André Raine to get to the remote mountaintops of Kauai, where they're working to save endangered Hawaiian seabirds from extinction.
Raine holding a Hawaiian petrel chick. Courtesy Kaua'i Endangered Seabird Recovery Project<p>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.</p><p>"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."</p>
An endangered chick in the mouth of a feral cat. Courtesy Kaua'i Endangered Seabird Recovery Project<p>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.</p><p>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.</p><p>The first step in controlling predators is quantifying the threat.</p><p>According to a paper Raine and his colleagues published earlier this year in <a href="https://wildlife.onlinelibrary.wiley.com/doi/full/10.1002/jwmg.21824" target="_blank">The Journal of Wildlife Management</a>, 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.</p><p>"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."</p>
Hawaiian petrel. © Ken Chamberlain, some rights reserved (CC-BY-NC). Via iNaturalist.<p>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.</p><p>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.</p>
Fence Me In<p>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.</p><p>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.</p><p>To make things even more difficult, the human visitors must leave the habitat as undisturbed as possible.</p><p>"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.</p><p>But the hard work pays off.</p><p>According to the paper, fences and other controls not only keep the invasive predators out, they give the birds the opportunity to thrive.</p><p>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.</p><p>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."</p><p>The paper, in what Raine acknowledges as gallows humor, calls this the <em>CATastrophe</em> model.</p><p>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.</p><p>"It really does show that if you remove the predators, the birds will begin to recover."</p>
The introduction of invasive species has been the primary cause of plant and animal extinctions over the past 500 years, a new study from University College London's (UCL) Center for Biodiversity and Environment Research found.
The study, published Monday in Frontiers in Ecology and the Environment, looked at 953 extinctions since 1500 and found that 126 of them, or 13 percent, had been caused entirely by alien species, while 300 were caused partly by the arrival of new species, according to a UCL press release published by EurekAlert!
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By Jason Bittel
My wife and I built a house two years ago on a few acres of woodland outside of Pittsburgh. The backyard is full of maples, poplars, briars and common spicebush. Two-lined salamanders and grumpy-looking crayfish wade among the rocks in the small stream that runs down the edge of the property. Deer, raccoon and opossum tracks appear regularly in the snow and mud. Sometimes, my trail-cam even catches a pair of gray foxes as they slink through the night.
The Genal Valley in Southern Spain is famous for its sweet chestnuts, and that could give the economically struggling region a huge boost as vegans and vegetarians in Northern Europe develop a taste for Castanea sativa. But a new threat is putting the valley's reputation, and future, at risk, BBC News reported Tuesday.
"We've lost at least 30% of our usual production," farmer Julio Ruiz told BBC News. "It is all the fault of a small wasp."
Tasmania's swift parrots can't catch a break. Logging has reduced their preferred blue gum breeding habitat by a third in the past 20 years. Sugar gliders, a kind of nocturnal possum introduced in the 1800s, are gobbling up female parrots at an alarming rate. And now, The Guardian reported Tuesday, scientists have found that the skewed male-to-female ratio is changing the mating habits of the endangered species in a way that puts its survival further at risk.
Earlier this week, a Florida man caught and killed a 17-foot, 5-inch female Burmese python in the Miami-Dade County Everglades.
The South Florida Water Management District (SFWMD) praised Homestead-based hunter Kyle Penniston's record-setting catch for its Python Elimination Program. Weighing 120 pounds, she was certainly a big one and she even bit Penniston's hand before she was shot on Monday night, according to his Facebook post.
They have displaced American alligators as the Everglades' top predators and have been found responsible for putting a dent in the populations of raccoons, opossums and bobcats, according to The National Parks Traveler.
Researchers at the University of Hawaii at Manoa and the state of Hawaii's Division of Aquatic Resources (DAR) have developed an innovative method of removing invasive macroalgae that can smother coral reefs, the University of Hawaii reported Aug. 9.
An invasive tick species was found to have spread to an eighth state Tuesday, when the Maryland Department of Natural Resources announced one was found on a deer in Washington County, The Washington Post reported.