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Training dogs to detect Zebra or Quagga mussels may be a new effective way to combat invasive species in Montana. Much like cadaver dogs, environmental watchdogs are being trained to sniff out invasive species in coastal waters. Through a collaboration between the state, several federal agencies, and the Montana Invasive Species Advisory Council (MISAC) dogs are being used to inspect boat docks and shorelines for the invasive mussels and prevent their spread. In addition to eating plankton that native fish species depend on for food, Zebra and Quagga mussels clog structures like pipes and disrupt water flow. These invasive muscles have already caused billions of dollars in damage every year in part of the United States like the Great Lakes. The hope is that the watchdogs will be able to detect adult mussels in the water and alert their handlers to the presence of these invasive species. Article by Elaine Hannah in Science World Report.
Susan Lee, Master’s student in Biology Research from the USGS was recently published in a study on the changing competitive dynamics between native and invasive trout species under climate change. This laboratory experiment examined the effects of warming stream waters in the Eastern United States (which is likely to occur with climate change) on competitive behaviors of native Brook trout. Observations were made with and without the presence of the widespread invasive Brown trout. Native Brook trout were more affected by warming temperatures in the presence of the competitively superior Brown trout. Researchers concluded that evaluation and management of invasive species will need to account for future increases of the interaction between climate change and non-native species effects. This reinforces the complexity inherent in dealing with invasive species issues. Conditions can be radically different through both space and time. The input from many disciplines is needed to act quickly and effectively to curb the ecological and economic costs that can often pile up. Original study published in the Canadian Journal of Fisheries and Aquatic Sciences. Shane Tripp, Master’s student in Geography Florida may be one of the most heavily “invaded” states, in terms of exotic species. One of the most notable threats to native wildlife in the sunshine state is the Burmese python (Python bivittatus), one of the largest snakes on the planet. Threatened in their native range due largely to overexploitation, the constrictor has established firmly in Florida, where it was accidentally released via the pet trade. Since their establishment over a decade ago, they have decimated populations of native, mid-sized vertebrates (i.e. rabbits, raccoons, foxes) and have even tried attacking alligators. Between these limousine-length snakes and other invaders, such as iguanas, hogs and giant African land snails, Florida has quite the management challenge ahead of it in the future. Not to mention rising sea-levels… Article by Steve Mirsky In Scientific American. Devin DiGiacopo, Ph.D. student in Biology "One of the biggest threats to broadleaf forests, the Asian long-horned beetle, could soon face new management practices in its invaded range. As reported in Science Daily, a collaborative project between researchers from the U.S. and Switzerland seeks to sequence the Asian long-horned beetle's genome and develop genomic management tools. So far, the researchers have successfully isolated genes that separate the invasive phytophagous beetle from beetles that do not eat plants. Of particular note is a set of genes that allow the Asian long-horned beetle to detoxify plant-defensive chemicals and continue eating undeterred. Because these genes are part of what make the beetle such a successful invader, they could potentially hold the key to effective management practices. Original paper in Genome Biology. Henry Fandel, Ph.D. student in Biology A new non-native species has just been found in the Great Lakes, reports the Milwaukee, Wisconsin Journal Sentinel. This species, a zooplankton called Thermocyclops crassus, is the first new non-native species found in the Great Lakes since 2006 when new regulations were introduced to reduce transport of non-natives in the ballast water of ships. Scientists are unsure if this species will become invasive or cause damage, but this discovery underscores the need to remain vigilant for potential biological invasions and continue to improve prevention measures. Andria Kroner, Ph.D. student in Biology
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 A “presidential” platyhelminth? Meet the Obama flatworm, one of the UK’s newest invasive species. In a rather humorous coincidence, this worm is actually not named after current US President Barack Obama, but from a combination of the words “oba” (leaf) and “ma” (animal) in the Brazilian Tupi language. The flatworm, a native of Brazil itself, was first discovered in an ornamental plant that itself originated in the Netherlands—meaning the problem is possibly bigger than it appears. It’s already confirmed that this species has a presence in several European countries, including Spain, France, and Italy. Although many flatworms are aquatic or parasitic, the Obama flatworm is a planarian, a group that contains several large, free-living terrestrial representatives. The Obama flatworm is a voracious predator of earthworms, snails/slugs, and other invertebrates, and their extreme hunger has already reduced earthworm populations by some 20% in some of its introduced range. With enough time, the flatworms could negatively impact soil fertility and ecology, making a variety of food crops and other utilities more difficult. Several experts and concerned citizens are calling for increased stringency in relations to imported potted plants, as several other species have also been introduced through this largely unchecked venue. Article by Jessica Aldred in The Gaurdian.
Isaiah Barker, Master's Student in Geography Image courtesy of Piterkeo This week the journal Diversity and Distributions published a new paper by Faulkner et al., that used geographic profiling techniques, originally designed to solve serial crime, to detect invasive species source locations. The authors compared the accuracy of models to predict source locations (invasive mink dens) when sightings from citizen scientists were used as data points versus when professional trapping data were used. The authors found that using sightings from citizen scientists were effective in predicting the source locations despite the much lower sample size. This study highlights the value of citizen scientists in detecting invasive species in a cost-effective manner, especially during the critical early phases when control or eradication is most feasible. Andria Kroner, Ph.D. student in Biology The Australian Wildlife Conservancy (AWC) has observed a notable pattern in the behavior of feral cats: the invasive predators heavily prefer hunting grounds that have been recently scorched by wildfire. The recent study published by McGregor et al. in Scientific Reports reported that cats traveled up to 8 miles outside of their normal home range in order to hunt scorched earth! Furthermore, the authors found that prey's chances of surviving a feline strike in scorched habitat were only 20%, marking a 60% difference in survival if attacked in dense habitat. As Australia continues to manage its feral cat populations, it appears that wildfire management will become a complimentary tool for suppressing the negative ecological impacts of this invasive predator. Article by Mindy Weisberger in Live Science Henry Fandel, Ph.D. Student in Biology Oceanic biodiversity is rapidly decreasing, but killer robots may help to undo some of the damage already done. Robots in Service of the Environment (RISE) is a group of scientists that has built a remote-controlled oceanic vehicle that sends a lethal electric shock to invasive lionfish and then collects their bodies with a net. Additionally, Drs. Matthew Dunabin and Feras Dayoub at the Queensland University of Technology have developed underwater robots that can identify the invasive crown-of-thorns starfish and inject a fatal dose of bile salts into the fish. Technologies such as these robots could be vital in the war against invasive oceanic species. Article by Kelly McSweeney for Robotics on ZD Net. Vanessa Wuerthner, Ph.D. student in Biology Trappers and waterfowl hunters reminded to avoid spreading invasive species. The thought of hunters as protectors of wildlife may seem counterintuitive to wildlife admirers. However, possibly no one wants to see a species flourish more than those interested in hunting it. Groups like Migratory Waterfowl Hunters inc., pour large amounts of money and volunteer person-hours into conserving species of interest, which collaterally benefit other species. Yet, hunting and other outdoor activities, pose another ecological risk to the native wildlife: the transport of invasive species. Aquatic invasive species, for instance, can be transported on boats, clothes and equipment. That’s why the Minnesota Department of Natural resources is urging waterfowl hunters heading into the field (or marsh) to take the time after trips to properly clean off. To properly clean boats that may harbor inconspicuous seeds or larval invasives (like zebra mussels), a high temperature and pressure spray is recommended. A short (30 second) video is available for more tips from the Minnesota DNR on what you can do to stop the spread of invasive species (http://tinyurl.com/jtf8tda). Article by Doug Hannerman in Hutchinson Leader. Devin DiGiacopo, Ph.D. student in Biology New Warning over Spread of Ash Dieback. Research by Fones et al. in Scientific Reports in the UK has predicted the spread of the Ash dieback fungus, Hymenoscyphus fraxineus, to be more infectious than ever. The disease causes leaf loss and crown dieback in Ash trees, usually resulting in tree death. Researchers once thought that the fungus was reproducing via sexual reproduction. This, however, is not the case, and the fungus has been discovered to reproduce asexually. Being asexual, the fungus can reproduce all times of the year and no longer just when leaf litter is on the ground. The fungal spores have been discovered on leaves, saplings, trees, and even in the surrounding soils of the Ashes. Also, the fungus is likely evolving at a faster rate than once expected, creating more variants and therefore more fungal strains. Hymenoscyphus fraxineus spores are likely moved in the soil of nursery plants. It is also likely that the fungal spores are moved by abiotic factors such as wind and water. The spores may even be spread by insects. It is possible that the fungus may affect other trees within the same family – including olive, lilac, and jasmine. The fungus has spread throughout much of Europe (researchers also believe American Ash trees are susceptible) and is not the only invader found on these trees. The Emerald Ash Borer is also leading to the demise of Ash Trees. Researchers must find a way to battle this disease without spreading it further in order to save these trees, but this is a challenge. A possible place to start is with a thorough understanding of the life cycle of the fungus, according to the researchers at the University Exeter. This may allow the researchers to know when it is safe to transport infected trees and when not to. Hopefully, something will be able to be done to protect these trees before it’s too late. Article in Science Daily. Brooke Florio, Senior in Biology  Invasive species are known to be one of the major contributors to amphibian declines across the globe. Such was the case for the endangered the Sierra Nevada yellow-legged frog (Rana sierrae) in Yosemite National Park. In the early 1900s, stocks of nonnative fish, mainly predatory trout species (Oncorhynchus sp. and Salvelinus sp.), were introduced into naturally fishless habitats. Stocking fish, along with disease, likely led to a massive decline in yellow-legged frog populations. However, with the help of restoration efforts, including cessation of stocking nonnative fish, this story has a happy ending. A recent study published in PNAS by Knapp et al. (2016) found that the frog’s abundance has substantially increased over the past 20 years, suggesting that the effects invasive species have on natural populations may in fact be reversible. Article by Shelly Leachman for Science Daily. Image courtesy of USGS (photographer: Devin Edmonds) Vanessa Wuerthner, Ph.D. student in Biology Invasive bush honeysuckles (Lonicera spp.) are changing the appearance of native birds. Yellow-shafted Northern Flickers have recently been found with reddish flight feathers. These abnormally colored birds are far from the range of western Red-shafted Flickers, which they are known to hybridize with and produce intermediately colored offspring. A recent study published by Hudon et al. in The Auk shows that the real culprit is the pigment rhodoxanthin, found in non-native honeysuckles. Berries of these plants have been known to cause color changes in other bird species such as the Cedar Waxwing and Yellow-breasted Chat. This has potentially detrimental effects on mate selection where color often serves as an indicator of fitness. Article by Douglas Maine in Newsweek Sheila Moore, Master's student in Biology Bad news for cat lovers everywhere… as they are being implicated in the extinction of dozens of species including rare birds, small mammals, and amphibians. A recent study by Loss et al. in Nature Communications has estimated that cats have killed somewhere between 1.3 and 4 billion birds, and 6.3 to 22.3 billion mammals every year. Island ecosystems are particularly vulnerable to feline predation. Since many of the species on islands have evolved in isolation away from mammal predators, many do not have the adequate defense mechanisms to evade domestic cats. One study has shown that cats are a threat to 8% of critically endangered island species around the world. It is not by random chance that cats have done exceptionally well in various habitats. Humans have transported cats and facilitated their spread all over the globe. Their high population growth can also be attributed to the supplemental food and resources they gain from living near or with humans. So what can be done to protect vulnerable species from cats? The idea of putting down huge numbers of cats is rarely appealing to the general public. Therefore, humans need to start acknowledging that if cats are going to be kept as pets, they should be treated like pets. This includes responsible pet ownership practices such as neutering and keeping them indoors. Article by Jacqueline Ronson in Inverse. Susan Lee, Master’s Student in Biology Entomologists around the world are saying in unison, “we told you so!" A recent study on the economic and financial impacts of invasive insect suggests that costs of these invasive pests come to around 69 billion euros’ worth of damage per year. That’s roughly 75 billion in US dollars. The results came from an extensive analysis of over 700 articles, books and associated literature, and all in all, they prove one thing: these pint-sized pests have a disproportionately large impact on both ecosystems and society. Some of the biggest offenders are often the least publicized; the voracious Formosan subterranean termite, the cabbage moth, and the spruce longhorn beetle each cause billions of euros/dollars worth of damage yearly. North America leads in terms of total financial loss at around 24.5 billion euros, with Europe showing a markedly lower loss at around 3.2 billion. It is important to note, though, that the authors suggest that this finding may come from a relative lack of documentation of economic losses in Europe. Health and agricultural industries are the hardest hit sectors, with insects consuming a whopping 40% of agricultural production worldwide, and billions of dollars’ worth in treatment and other costs associated invasive species. Article in Science Daily. Isaiah Barker, Master's Student in Geography In the fight against the invasive hemlock woolly adelgid (Adelges tsugae), one university is taking a stand. In 2009, Cornell University found the invasive insect in stretches of its 700-acre tree plantation. The insect attacks hemlock trees, feeding on sap, destroying pine needles, and typically results in mortality of infested trees. Because of this infestation, researchers at Cornell have begun to look for forms of biological control for the insect, such as introducing predators from their native range in Japan. With Cornell having one of the world’s leading agricultural and pest management departments, it has become clear that the hemlock woolly adelgid chose the wrong plantation to infest. Article by Max Carol in Treehugger. Nick Buss, Ph.D. student in Biology Sweden’s attempt to ban American lobsters in the EU has officially been denied in favor of pursuing ‘alternative measures.’ A small number of American lobsters captured in European waters sparked fears of eventual establishment and full-on invasion. Swedish scientists touted risks of the American species not only out-competing native lobsters but of breeding ultra-competitive hybrids that could one day overwhelm their entire range of habitats. This is a common thread in invasive species management, but in this case, it is not known if hybrids are even fertile let alone more fit than either contributing species. The other fear noted by the Swedish is the risk of American lobsters facilitating the invasion of American diseases that the European species would be undefended against. This would then further increase the invasion potential of the American lobster. This argument is refuted by American lobster researchers claiming that native populations are largely disease-free and thus are unlikely to bring diseases even in the worst-case scenario of an invasion. The block is being blamed on the power of the American lobster fishing industry which has been booming in response to recent environmental changes in the native range. Climate change has increased reproductive rates while overfishing of lobster predators has decreased their mortality rates, increasing populations and profitability. The battle is not yet over as we are yet to see what ‘alternative measures’ might be proposed and how each side may then respond. Article by Shawn Donnan in the Financial Times. Shane Tripp, Graduate Student in Geography And now featuring some of our research! Just out in Ecosphere, University of Florida PhD student, Patrick Milligan led a project examining the putative effects of an invasive ant on a key ecosystem function (decomposition) in an African savanna. The Big-headed ant (BHA), Pheidole megacephala, is one of the IUCN “world’s worst invaders” owing to its ability to form large “supercolonies” (expansive colonies) where introduced, its protein-loving tendencies, and its ability to recruit large numbers of ants to resources - including to my unattended tea snacks at the Mpala Research Station in Kenya. BHA is not only a nuisance to people, but it likely has large effects on ecosystems – it has been found to devastate arthropod communities. A recent invader to the Laikipia region in Kenya (a conservation hotspot due to its intact large animal community), we noticed that BHA heavily recruits to animal dung. The ants are likely capitalizing off of resources in dung. For the protein-loving ant this could mean arthropods that play functionally important roles in dung decomposition (beetles and termites). Pat collected a lot of cow dung and set up an experiment to test BHA impacts in the field. He put out dung pats and pitfall traps (cups in the ground) in locations invaded by BHA or not, and counted and identified dung associated arthropods. He found that while BHA reduced the abundance and diversity of arthropods, the functionally import guild of arthropods involved in decomposition were resilient to invasive ants. This paper nicely highlights that to uncover consequences of invaders, we need to go beyond assessing impacts on species diversity alone and also consider effects on functional guilds and the services they provide. Kirsten Prior, Assistant Professor in Biology How can scientists detect potentially invasive species at low densities before they become a serious issue? As Science Daily reports, University of Illinois aquatic ecologist Eric Larson and colleagues from Notre Dame recently used environmental DNA (eDNA) to detect the presence of rusty crayfish in two lakes the invasive species has never before called "home." This methodology is promising as an early warning system because of how sensitive it is to detecting species within an aquatic community. In fact, eDNA is so sensitive that Larson concedes he may have found false positives; traces of rusty crayfish DNA may have been deposited in the lakes by water currents or a predator. While the eDNA technology is not refined enough to estimate the number of individuals of a given species within a community, it is a promising tool for testing for presence or absence before a known invasive species burgeons to a troublesome population size. At the very least, it gives managers a good idea of where to focus their search efforts. As for determining whether Larson was indeed reading a false positive…let the crayfish surveys begin! The original study was published in the Journal of Applied Ecology (Dougherty et al. 2016).
Henry Fandel, Ph.D. student in Biology A new study by Bradshaw et al. in Nature Communications estimates that invasive insects cause at least $77 billion USD in damage per year. The authors warn that this is a gross underestimate due to lack of research outside Europe and North America. Insects cause widespread damage through the spread of infectious diseases, destruction of crops, damage to infrastructure, and disturbance to ecosystems. The rapid spread of invasive insect species is causing massive economic costs and global warming is likely to increase their spread towards the poles. According to one of the authors, Frank Courchamp, more pesticides or genetic manipulation to combat invasive insects is not the best solution. Instead, he recommends improving bio-security in international trade. Sheila Moore, Master’s student in Biology Bigger isn’t always better, especially when it comes to nonnative species invading new areas. A recent article published in Nature Communications by Early et al. (2016) found that most of the world is exposed to invasions due to travel and commerce, and that developing countries comprise some of the most vulnerable areas across the globe. Additionally, because developing countries don’t often have the resources to respond to invasion events, things like the invasive 440 pound Nile perch are likely able to eat over 200 native fish into extinction. Article by Natalie Jacewicz for NPR. Vanessa Wuerthner, Ph.D. student in Biology "Want to get rid of invasive species? Eat them.” A recent article in The Week highlights a growing movement to include invasive species on the menu at home and in restaurants. Coined "Culinary Conservation," multiple organizations (Eat the Invaders, Invasivore.org and Eradication by Mastication) have provided recipes and hosted events centered around invasive-oriented cuisine. The movement has found a home in multiple restaurants serving up species like the Asian carp and lionfish, which pose serious ecological and economic harm to their invaded ranges. Critics of the movement warn against the dangers of creating a demand for species we hope to eradicate, but for species like the Asian Carp, which have become perhaps irreversibly established, including them in our diet may be a good way to put their persistence to use. Devin Digiacopo, Ph.D. student in Biology Eradicating Invasive Species One Sushi Roll at a Time (New York Times). Chef Bun Lai is doing his part in helping to curb the threat of invasive species the only way he knows how – through making them what’s for dinner! For the past several years, Bun Lai has been serving his guests at his New Haven, CT restaurant local invasive species such as lionfish, Asian carp, and Asian shore crabs. According to the article, The Truth is in the Muck, In Popular Mechanics, "Bun [Lai] discovered that the crabs could be pan fried in olive oil and seasoned, creating a taste that is an uncanny imitation of a Dorito." Mr. Lai has more recently opened up shop in Miami FL and has his sights set on the many invaders in the Sunshine State, such as feral pigs, and invasive seaweed, which are becoming all too common within the Everglades. Through Mr. Lai’s example, hopefully others will follow suite with this sustainable initiative - and start to enjoy bags of Asian shore crabs as a snack! Nick Buss, Ph.D. student in Biology Samantha Klein, Junior in Environmental Science Try to name the tiny orange-googly-eyed critter swimming around in a bowl on the stand in the living room or on a desk in a bedroom – perhaps with a little castle that has a picture of a mermaid on it? If goldfish came to mind – your thought process was correct. These aquatic inhabitants are very different in the wild however – which is where they have been found in three countries now – the US, Canada, and Australia. In the wild, goldfish retract back to their original colors, yellow and brown after just a few breeding cycles and they increase in weight to about the size of a 2L bottle of soda. This happens because in nature the fish are not being bred by people to be orange and because goldfish in nature have a wide diet. Female goldfish in the wild can lay upwards of 40,000 eggs every year, and survivorship is high due to a lack of natural predators. Goldfish are long distance swimmers (seems unlikely from keeping them in a bowl) so they can migrate effectively and efficiently to new areas to spawn and to live. These fish have large ecological effects – they swim near the bottom of the lakes/ponds/rivers and uproot the vegetation, leading to nutrient leaching, algal blooms, and eutrophication. So how are these cute little fellows getting out of their bowls and into nature? Human introductions are the leading cause, setting them free, and likely unaware of the severe ecological impacts that they can have. Goldfish are now listed as an invasive aquatic species. The best way to manage these fish is prevention – don’t want your fish? Don’t let it go or flush it! Donate them to recommend local pet stores or other owners – whatever you do, just don’t let them free! Article: In the Wild, Goldfish Turn from Pet to Pest (The New York Times). Brooke Florio, Senior in Biology When we think about invasive species, we commonly think of species that have been transported over long distances and impact ecosystems within which they are completely novel. However, we also move species short distances, or introduce novel populations of species into areas in which native populations of the species already occur – “native invaders.” Given the increasing appreciation for how variation within species can influence ecosystems – we should wonder what the ecological impacts of native invaders and altering intraspecific (within species) diversity are? For example, captive breeding programs for conservation, or breeding species for aquaculture or agriculture (including transgenic alteration) alter species “traits” (e.g., faster growth rates, or increased ability to resist disease). These “populations” of species can be intentionally re-introduced back into their native environment (i.e., where wild populations occur) – fish such as rainbow or brown trout raised in hatcheries are stocked into water bodies to enhance commercial or recreational fishing. Populations can also be unintentionally released – 2 million Atlantic salmon escape aquaculture in North America every year. Buoro et al. in Ecology Letters conducted a meta-analysis (an analysis of studies) to compare the ecological impacts of native salmonids (salmon and trout) invaders to non-native invaders that have been introduced to locations that have native salmon species or no native salmon species, respectively. They found that “native invaders” at least rivaled or possibly exceed the impacts of non-native invaders. However, impacts of native invaders were only documented at the lowest level of ecological organization (impacts on behavior or fitness of native salmon). We currently know little about the effects of native invaders on other species in communities or in ecosystems. This study highlights that what we know about the impact of invasive species is likely only the tip of the iceburg, and that we need to think about invasive species more broadly than species that are moved over long distances. Kirsten Prior, Assistant Professor in Biology This past week in PNAS (Proceedings of the National Academy of Science) a new paper by Tim Doherty et al., was published on the global impact of invasive mammalian predators. After conducting a global meta-analysis, the authors found that these invasive predators are responsible for 58% of extinctions of birds, mammals, and reptiles that have occurred since 1500 AD. Nearly half of which are attributable to cats and rodents alone! Unfortunately, the most affected groups of species are those that are most “evolutionarily distinct,” or unique compared to many other species. This underscores the critical need to manage these invasive predators to preserve global biodiversity. Andria Kroner, Ph.D. student in Biology Sweden’s recent push to ban American Lobsters from the EU highlights issues concerning the categorization and management of invasive species. Several individuals were discovered in the wild which drummed up fear that they would become established and begin to wreak havoc on native species. This problem is mirrored by the lifted ban on monk parakeets in New Hampshire. The species is a pest in warmer climates but has yet to successfully establish in the wild wherever winters can be harsh. The policy paradigm resultantly switched from blacklisting banned species to whitelisting acceptable species. This places the burden onto potential importers so that they must prove that a species will not turn invasive if released. This also lightens the load on the bureaucracy in light of difficulties such as the complexity of predicting invasiveness and that invasions can be ‘natural’ in the face of a changing world. Article by David Brooks in the Concord Monitor. Shane Tripp, Master's student in Geography The Asian Hornet has been spotted in Britain for the first time (BBC NEWS), sending the Department for Environment, Food, and Rural Affairs on a quest to find and eliminate their nests. The invasive hornet doesn't pose a direct threat to humans, but it does to the native honey bees. Honey bees are responsible for plant pollination, which helps to provide a critical food source for humans. If honey bee colonies decline, so does the ecosystem services it provides. This invasive species could alter ecosystems causing a cascading effects, by changing honey bee populations and plant communities. Queens of the Asian hornets' nests are being targeted so that this invasive colony dies out and isn't able to establish. Samantha Klein, Undergraduate student in Biology European frog bit: don’t let the name fool you, as America’s lakes are in for more than a “bit” of trouble. On paper it looks like more than your typical lily pad—green, round, and likely a favorite of the creature that serves as its namesake. However, in America, it’s a bit of a different story. Without consumers and diseases to keep the plant in check, frog bit goes wild: the result is thick mats of light-blocking vegetation that even impede the movement of boats and other recreational/commercial activity. It’s a two-for-one series of bad tidings for affected waterways, however. When the plants eventually die back en masse, the sheer amount of rotting material can turn healthy lakes hypoxic, tipping the balance of lake ecosystems for the worse. For now, the plant has only been spotted in the Fisk and Reeds Lakes in Michigan, but as one researcher notes, “As aquatic invasive species go, frog-bit is near the top regarding concern.” More concerning still is the lack of a plan to eradicate it, although it is known that the plant is already too established to pull by hand. Article by Jan Holst in mLive. Isaiah J. Barker, Master’s student in Geography @chitincladheart An article in the Daily Cardinal is informing the public about a ‘tiny in size but large in impact’ invasive species, the Asian jumping worm - Amynthas agrestis. Jiangxiao Qiu, from the University of Wisconsin, Madison published a paper on the ecological impacts of this invader in Biological Invasions. The Asian Jumping Worm can consume up to 95 percent of the leaf litter in an area in approximately four months! This is because where present, they occur in high densities -numbering upwards of 150 worms per square meter. This barely allows the plants themselves to absorb the nutrients that the leaves would normally provide to the trees and soil and accelerates the timing of nutrients being released into the surrounding soil. Without being absorbed, these nutrients may be flushed into sources of ground water. The high concentrations of nutrients in the soil provide potential habitats for new invasive species to germinate, while making it a poor environment for many native plants. Humans may provide some helpful controls on the worms by putting down fertilizers and treatments made especially for them. In all, the article is an important read for those living in Wisconsin and surrounding states, as the Asian Jumping Worm can be moved in the soil of nursery plants and can cause turmoil if given the opportunity to establish. Brooke Florio, Senior Undergraduate in Biology Zebra and quagga mussels are two of the most notorious invasive species in the Great Lakes. Despite numerous introductions, these mussels have failed to establish in Lake Superior. In this article, fishery research biologist Don Schloesser explains that Superior’s cold temperatures, scarcity of phytoplankton, and low calcium levels contribute to the lake being an inhospitable environment for zebra and quagga mussels. However, this does not mean Lake Superior is safe from these invasive mussels. At first, Lake Michigan also seemed immune to these invaders, but they are now found at the lake bottom in high densities. Time will tell if the molluscs can adapt and conquer the final Great Lake. Sheila Moore, Master’s student in Biology Do invaders always have negative impacts? Although they certainly have a bad reputation, the answer is no! Impacts on communities and ecosystems depend on the traits of interacting native and invasive species, and the outcomes of complicated interactions among species in the context of their environment. This important point was highlighted in a nice study lead by Catherine Searle from Purdue published in The American Naturalist. The team predicted that an invasive water flea Daphnia lumholtzi would likely increase disease transmission of a fungal pathogen because its susceptibility to the pathogen was relatively higher than a native species. However, in experiments in miniature artificial ecosystems, they found that the presence of the invader decreased disease presence! The story was just not as simple as disease patterns relying on the relative susceptibility of these species. Rather the outcome of competitive interactions on the population dynamics of these species ultimately influenced patterns of disease – which was unexpectedly lower in the presence of the invader. Kirsten Prior, Assistant Professor in Biology A new paper in Nature Communications by Regan Early (University of Exeter, Cornwall) et al. projected global patterns of threats of invasive species based on 21st century patterns in trade and traffic and environmental change. The authors found that “1/6th of the global land surface is vulnerable to invasions, including substantial areas in developing economies and biodiversity hotspots.” They also mapped countries’ capacities to prevent and manage invasions. They found an increase in invasion risk in many countries with historically low levels of invasions (in the Southern hemisphere) – several of these countries are at particularly high risk due to a limited capacity to deal with invasive species.
Revenge of the goldfish! Dumped pets growing into giant monsters! This article in treehugger left me wondering about the fate of my first goldfish, won from the Milton Fall fair, released into my hometown pond unknowingly by a naïve animal-lover who felt guilty for keeping him in a confined space. The pet trade is a major pathway by which species are introduced, establish, and sometimes become invasive. With limited regulations, one of the best ways to mitigate future invasions via this pathway is to educate the public (i.e., young animal lover kids with seemingly good intentions). Goldfish are a widespread invasive in several countries, becoming very large outside of the confines of their tanks, eating eggs of native species, introducing disease, and disturbing habitats. The original study is by Stephen Beatty et al. in Ecology of Freshwater Fish. A longstanding controversy in invasion biology is that there is limited evidence that invasion cause species extinctions via competition, especially in plants. In fact, several studies show that non-native species actually increase diversity. These are valid points with implications for management – the impacts of invasions are overstated and in many cases, we should just let them be. While I am certainly not an advocate for killing all invasive or non-native species, I find these arguments problematic for several reasons. A recent article in Scientific American highlights one reason, that invasive species could push some species along an extinction trajectory. While there are few documented cases of invasions causing extinctions, “plant extinctions are an agonisingly slow process,” stated one of the authors Dave Richardson (Centre for Invasion Biology at Stellenbosch University) of the original study in AOB plants. Population extinctions precede species extinctions and plant population loss, fragmentation of populations, and shrinking populations all increase risks of extinction. Thus, just because we don’t have direct evidence that invasions cause extinctions shouldn’t preclude us from trying to manage invasions that contribute to the movement of species towards extinction. We know that only a small sample of non-native species that establish outside of their historical range become invasive (spread and impact). Capybaras (large rodents) are likely becoming established in Florida from a handful of individuals that escaped from a research facility. Although not invasive yet, they have the potential to become invasive because they are social and resilient animals that eat crops. As species establish (start to grow in population size) and become invasive, they are increasingly difficult and expensive to manage. Thus, it is important to try to manage small populations of species before the form larger populations and spread. The challenge is then trying to predict if species will become invasive and if management is warranted. This is very nice read on the success story of the sequential eradications (complete removal of a population of an invader) of several invasive species from Santa Cruz Island in California. Management of invasive mammals on islands has been a huge success. There are hundreds of successful eradications, and in most cases eradications lead to conservation gains. However, mammals are easier to eradicate than other invasive species such as hard to detect insects or plants with seed banks. The most recent eradication effort on Santa Cruz is perhaps the hardest of all – the Argentine ant. Eradication success decreases with the likelihood that species will reinvade and when finding every last reproductive individual (in this case queens) is difficult. The team thinks they have a good chance of killing most, but not all of the ants – all is a pretty tall order! The future for lionfish might be shocking! There is bad news for invasive lionfish – the non-picky invasive predator that is ravaging fish and reef communities in the Atlantic. The bad news is the “Lionfish Terminator,” a robot that seeks out, sneaks up on, and zaps the fish. These fish are hard to manage because they swim deep, but not too deep for the robots. Advances in technology like this will greatly aid in more effective environmental management. |
