Video: Invasion of the Ecosystem Snatchers!

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[Georgeann Moss]: Good afternoon everyone, welcome to Dallas County Community College District's Sustainable U webinar called Invasion of the Ecosystem Snatchers by professor Brie Day of Eastfield College. This is the second in a continuing series of webinars. It is co-sponsored by DCCCD and EarthX, who is our valued partner. My name is Georgeann Moss and I'll be your host today. I'm the executive administrator of sustainability outreach and initiatives for Dallas County Community College District. Before Professor Day starts, let me go over a few housekeeping items. There are three ways to communicate with us today, first is chat, second is Q&A or question and answer, and the third is polls. Please use the Q&A function for all of your questions. If Professor Brie doesn't have time to answer your questions during the webinar, she will get back to you afterwards and answer your questions. Use the chat function for comments that don't need an answer to them, and the reason we ask this is because if people continually comment, then we cannot – if you put a question in the chat box, we can't answer that comment directly. And then finally, Dr. Day will activate poll questions, and all you have to do on that is it'll pop up on your screen and you just select the answer and hit enter, so that's real easy. So to find the chat box and the Q&A, if you'll just hover your mouse over the bottom of your screen and there's a nav bar there, if you'll click on the little icon that has three dots in it, and you'll have a choice to go to either chat or Q&A. If you're experiencing technical difficulty, please go into that three dot icon, select Q&A, and use that for help and we'll try to help you. You've already read Professor Brie Day's bio on the website and so you registered and so she's gonna tell you a little bit more about herself during the presentation, so I'm going to turn it over to Professor Brie Day. Thanks so much for joining us.

[Professor Day]: Okay, hi everybody, can you hear me? Hopefully. Thank you, Georgeann, thank you all for letting me be part of this initiative. I'm really excited to talk to you about invasive species and how they are wreaking havoc on ecosystems in this country. Again, my name is Brie Day, I'm a professor of biology at the Eastfield campus of DCCCD. I've been here about five years, and I moved here from Hawaii, where I was teaching full time at Hawaii Community College, and before that, northern California, Oregon, southern California, been all over the place, but happy to have my feet planted here in Texas. So we are entitling this talk Invasion of the Ecosystem Snatchers, and you will see why in a bit. So I'm gonna go ahead and play this pre-recorded lecture, originally I had my talking head in it but we were having technology issues getting the face and the voice to sync, so it'll just be a voiceover and then I will come back at the end and we're gonna go over some quiz questions and see how you did on on learning about invasive species. So here we go. So I'm entitling this talk Invasion of the Ecosystem Snatchers because invasion biology, as it's called, the study of invasive species, reveals some fascinating characters that, when put together, would make a really great science non-fiction film or even a horror story. So we're gonna be going over just a few examples of invasive species in the United States and really looking at what is it about those species and about the habitats that they invade into that allow them to snatch up ecosystems and spread the range. Invasive species are the biggest threat to biodiversity, second only to climate change and habitat destruction. Invasives harm our lands, our waters, and our native species, and the rate at which invasives are spreading calls for a whole field of study called invasion biology, which is the study of invasive species and their effects on native ecosystems. Now, not only do invasives effect biodiversity, but they also carry a tremendous economic cost for humans, to the tune of about $145 billion dollars each year. Now, just because a species is introduced into a habitat doesn't make it an invasive. In other words, all invasive species are introduced, but not all introduced species are invasive, and the reason why is it's actually somewhat rare for a species to become established in a new area, meaning that they actually spread enough to reproduce and carry on generations. Now, certain habitats make it more likely that they will be vulnerable to invasive species, specifically habitats that are already stressed. So this would be a lot of urban habitats where you have species exposed to pollution or areas that are not protected, so for example, areas of land that have not been declared state parks or national parks, and also habitats where there's a history of a previous introduction or multiple introductions. So a lot of times we want to concentrate some of our efforts in these more vulnerable habitats for helping to curb the spread of the range of invasive species. So invasive species come in all sorts of shapes and sizes. We have vertebrates, invertebrates, plants, you name it. Here's just a quick example of some vertebrates that unfortunately I won't have time to go into detail on today, I wish I did. Here we have the Burmese Python, a feral hog, Cane toad, Northern snakehead fish, and the European starling. Now, despite the vast diversity of species that can be invasives, most of them share some common characteristics. Number one, really fast reproduction and growth, so they tend to have really short, flexible lifecycles, so they can produce lots of babies and those babies grow really fast so they can grow up and have babies, so they can just kind of flood the market with lots and lots of babies. So they also are very good at dispersing those babies. In the case of plants, it might be with wind and or animals, in the case of animals like the lion fish you'll hear about is they put out the larvae that get swept away in the currents, lots of ways that they can get distributed. They also tend to have alternate reproductive options, so they can go with multiple ways of producing babies, so you'll hear about the Chinese privet later on that has both the sexual and the asexual lifecycle so it has multiple ways of growing more of itself. Also, invasives tend to have broad tolerances, so they're rather tolerant to things like pollution, soil chemistry in the case of plants, light regimes, and they tend to be generalists, so they don't specialize on one particular food source or one particular set of other resources. They can adapt to many different food sources, many different environmental factors, and they tend to really be aided by human activity. So for example, you'll hear about the Asian tiger mosquito which just absolutely loves human containers, like tires and bird baths. And finally, you tend to find that invasives are able to expand their range and outcompete native species because they leave behind their natural enemies, their natural predators, competitors, parasites and diseases. This is of particular interest to me, I'm very interested in how escaping parasites can allow an invasive species to outcompete native species that are stuck with their own parasites. So we're gonna start off our examples of invasive species with one that's well known by a lot of people, the kudzu plant, so better known as the plant that ate the South, because when it gets into a place, it just takes over everything. So you can see here it's completely covered these houses, a school bus, it just completely takes over, and it was intentionally introduced into the United States in 1876 for the Philadelphia centennial exposition, and again later in the 1930s and '40s, it was actually given to farmers as a way to control soil erosion and put nitrogen back in the soil, so it was considered to be a good thing and I'm not sure that they had anticipated how once this thing gets out, it just takes over. So by the 1930s, it had already covered over a million acres, and it's continued to grow at about 2,500 or more acres per year since then. So now it's really, really hard on ecosystems in addition to just covering everything. It outcompetes native species, so it outcompetes native plants for light and nutrients and in the process, it actually changes the whole soil composition. When it gets into an area, it actually decreases soil carbon by 28% because it completely changes the leaf litter composition of the area, so this affects native plants being able to grow there and of course, any insect or other creature that depends on those native plants is gonna be affected. So, big effect on the ecosystem, and it is an ecosystem snatcher as you can see, and it's also been planted in other areas, for example, some islands like Fiji, the US military actually planted it as a way to hide their equipment, so to camouflage their equipment. Now, removal of this is extremely difficult, you – it becomes huge, and really what you have to do is get in there and remove what's called the crown root. If any amount of the crown of the root is left, it can generate more vines, so you have to get rid of that. Of course, they'll try to use herbicides and other kinds of chemicals to get rid of it, but that has ecosystem effect, and some of the more successful methods for removing this is through grazing by things like goats and llamas. They've done this Tennessee and actually had some success with it. They've also tried burning and then using a skid loader to remove the crown roots. So different methods, better to try to prevent it, if you happen to see it growing, remove it, but the good thing is you could actually use this for food. So now of course, kudzu is native to Eastern and Southeast Asia, and it's been used as both a food item and a medicinal item for probably thousands of years. So you can actually eat the blossoms, you can make a jelly out of it, so if you go online you'll find lots of recipes for making kudzu jelly in the South. You can eat the roots and turn them into a starch that could be used as a replacement for corn starch, you can actually take the young leaves and shoots and fry them or steam them, so all sorts of stuff you can do. They've even now in the South made soaps out of it, they are starting to make clothes, you can make baskets out of it, so it's very, very versatile and it seems like it might be here to stay so maybe use it as a way, as an alternative source for materials for items that we might need. Now in medicine, it's supposed to be this wonderful cure all. So you can make a tea out of it and that's supposed to help with everything from hangovers to nausea, headaches, heart problems, you name it, so if you Google that online you'll find lots of information about how it's been used in traditional Asian medicine and is also being used by a lot of herbalists here in the United States. For the future of kudzu, we'll see what happens. As you can see it's all over the Southeast, even into Texas and even a little bit up in the Northwest. There is now a beetle that is one of its native enemies back in Asia, the kudzu beetles, this cute little thing has actually now been found in the Southeast and really seems to wreak havoc on this guy. So that might be the biggest promise, and that's kind of typical of a lot of invasive species, that there's a lag time between when the invasive gets here and when its natural predators or parasites are able to catch up with it and control the population. One of the most aggressive invasive species on the planet, the lion fish, and don't let the good looks of this guy

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this beautiful fish is dangerous and he's dangerous not only to humans, but to the Atlantic coral reef ecosystem. So the lion fish was first found off the coast of Florida in the mid-1990s, probably was introduced and has had subsequent introductions from aquarium enthusiasts who just let him go, maybe got tired of him. So you can still find these guys in aquariums, I've seen them at local pet stores and that's not such a good thing. So however it was, they were released and they have just been reproducing like crazy. Each female, every time she reproduces, produces two egg sacs and each egg sac has 15,000 eggs in it, and of course, like so many invasives, these guys have left behind their natural predators in their native habitats. These guys are native to, for example, Korea, Eastern Australia, Indonesia, some of the French Polynesian Islands, and once they got here, they have just absolutely wreaked havoc. So their population size has increased 700% between 2001 and 2008, and in the process, they have outcompeted native top predator fish and therefore destroyed ecosystems. They're very aggressive fish, they've led to an 80% reduction in Atlantic coral reef diversity. So one of things that happens is, because they're so aggressive, they'll actually kind of scare off other would be predator fish that help to maintain te balance of the ecosystem, so those top predator native fish end up going to less desirable reef areas, and meanwhile the lion fish just takes over and wreaks havoc everywhere. So since their introduction into the waters off the coast of Florida, they've made their way all through the Caribbean and even down to South America, so the ocean currents and even ballast water ships just take them everywhere and they invade, they're aggressive, they outcompete native predators. In one study, they actually found on a single reef, there had been a 79% reduction in native juvenile fish when the lion fish was present, so these guys are really out of control and the best methods they're finding for controlling these guys is actually marketplace initiatives. So NOAA and other agencies are really encouraging humans to catch these guys and eat lion fish as food. So you know you can't – you don't want to touch the spikes, but if prepared properly, these guys could be deep fried and they're supposed to be delicious. So they're really trying to encourage restaurants to serve them and they'll actually even send people in to train chefs how to cook them properly. They're also starting to sell parts of the lion fish as jewelry, so for example the tail or the spikes they can sell as jewelry, and this actually does seem to be having a positive impact on reducing the populations. But, like so many invasive species, once established, it may be a losing battle, because they don't have the natural predators that they would in the native habitats to keep their populations under control, and because they're so good at outcompeting natives who do have their natural enemies, these guys just continue to spread everywhere. So one of the ways they were actually able to make the eat lion fish as food campaign successful in Colombia was they negotiated with the Roman Catholic church to tell their congregations to eat lion fish on Fridays, at Lent, and on Easter, and so that actually did make a significant reduction in the lion fish populations in that area. But again, these guys reproduce so quickly and they are aided in their dispersal by ocean currents and ballast water, and they don't have any predators so this is a real challenge to try to control. So again, the best best cure for invasives is prevention. Once they're established, it's very, very difficult to stop the invasion. So the next invasive species we're gonna talk about is Chinese privet, also known as white wax wood in Asia where it's from. Now, Chinese privet meets all of the characteristics of an invasive species, it's got it all. It loves to stir up human habitats, it has characteristics that allow it to greatly expand its range and outcompete native species, it has it all. So this species is native to Asia and Europe and was first introduced in the United States in the 1800s. Specifically, they were trying to introduce it as an ornamental shrub to be used as hedges, and since then it has taken over, it's expanded into 20 different states, 78 counties here in Texas, including Samuell Farm in Dallas county, right sort of on the border between Mesquite and Sunnyvale, and so I was there just the other day and took a little video of privet, so check out this. This plant can grow to 30 feet in height and it just takes over everything, so it's only been at Samuell Farm for about 20 years and you can just see how it's completely taken over, and it's very sad because one of the things this plant does is it likes to encroach on forests, so you can see a little bit of some of the tall hardwood trees that grow in Samuell Farm, and just over the years, even in the last couple years, I've noticed just this privet will go in there and just start encroaching on the forest and choke out the trees. So really sad and really hard to remove. So because of how invasive Chinese privet is, it's considered to be one of the largest threats for ecosystem modification of any invasive in the country. This guy completely destroys ecosystems. Some of its characteristics that allow it to outcompete natives is it grows very, very fast, it's shade tolerant, it can adapt to different shade regimes. So for example, when it's low – there's low light, it'll change how it grows so that it can adapt to that light. So another characteristic of Chinese privet that allows it to take over and outcompete natives is it has both sexual and asexual reproduction, so it can produce seeds and it does, it produces, after these flowers are done, tons and tons of seeds that will turn black at one time of the year, and it's just incredible, you try to get rid of the privet and you end up spreading the seeds everywhere and it just takes over even more. It also can reproduce by sending vegetative roots underground that themselves will sprout new Chinese privet plants. So it just really takes over everything, and it has no natural predators or parasites that it would have in its native Asia, and so it's really occupying just an open niche in the United States, and it's certainly taken advantage of that. So this guy is especially invasive in riparian habitats, so those are areas around like a stream, for example, and over there you find very vulnerable native plant species, while the Chinese privet is very tolerant, not only to shade but to pollution, human disturbance, it loves all that and takes advantage of it so it's very easy for it to outcompete native plants, and in doing so, it not only changes the vegetative composition of an ecosystem, but that ends up changing the whole ecosystem. So it changes who's the dominant plant and in the process, it changes the nutrient cycling that goes on in the soil. So for example, in areas where Chinese privet has taken over, like you see here, you actually get decomposition of leaf litter in the soil more than two and a half times what would naturally occur, so that changes the chemical composition of the soil, which further changes what kind of plant life can grow there, and in turn, you end up changing the animal life as well. So studies have been done that found, in areas where Chinese privet had taken hold, you see lower diversity of butterflies, you see lower diversity of honeybees, so it really does have a huge impact on ecosystems, and the fact that it encroaches on forests around riparian habitats is going to lead to a total overall loss of biodiversity, because anything that depends on those forest trees will also have decreased biodiversity of those species. The Chinese privet, definitely a major invasive in the United States. It's already invaded over a million acres of land from Virginia down to Florida and west to Texas, very difficult to remove, about $737 per acre to try to do a mechanical removal where you chop, basically chop down the bush and then followed by some kind of chemical application, and of course in addition to trying to remove these bushes, they try different kinds of herbicides to get rid of it and that comes with a whole host of other concerns for the ecosystem. So once they get in there, they're kind of – they can take over, as you see here at Samuell Farm. There's been efforts at Samuell Farm to remove them and they just keep coming back, so very difficult to chop down because they're vegetative, they can just send out shoots somewhere else, you try to remove them, the seeds go everywhere, so it's definitely a problem. They tried burning the stumps after cutting them down, but better to try to prevent than to try to deal with it after it's invaded, so if you happen to see privet in your area, young privet, do try to remove it as possible – if possible, to keep it from spreading, but definitely report it. So certainly the Texas Department of Agriculture is very interested in knowing where privet is located so it can keep track. So scary scenario, scary plant, definitely meets the characteristics of an invasive species. So our next invasive species, near and dear to the hearts of most people, but I'm one of the few people that actually have a soft spot for the Asian Tiger mosquito in a weird way, because I worked on the Asian Tiger mosquito for my master's thesis. So the Asian Tiger mosquito, better known as aedes albopictus, or now they're calling it stegomyia albopictus, is a highly invasive mosquito from Asia, and we know that it got to the United States in 1985 via used tires brought over from Japan, so they brought them actually to Houston, Texas, and in a very short period of time, this mosquito was able to expand its range and is now found all over the eastern part of the United States all the way up as high as

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and as far west as Nebraska, so it really has taken over, and one of the things that's enabled the species to expand its range, like so many invasives, is that it is able to outcompete the native species, in this case native mosquitoes like the native tree hole mosquito, and therefore expand its range. So it's definitely a health concern, the Asian Tiger mosquito carries diseases so it's able to carry yellow fever, Dengue fever, and is even a possible host for Zika virus that's been in the news a lot, so definitely a health concern. Health departments are all over trying to control larval populations of these guys. So you can see it's very distinctive, it's a dark colored mosquito with this distinctive stripe down the back there and little white stripes on its legs. So very pretty mosquito, unlike the native mosquitoes it's not just active in the evening and the morning, it is able to bite you any time of the day, and of course, only the females are the ones that actually suck blood. They need the blood meal to get the protein to be able to lay eggs. The males, as well as the females, like to drink things like nectar or any kind of sugar water source. I used to raise them in the laboratory for my thesis and I'd make a little sugar pad of cotton soaked in sugar water, put it in a petri dish with a screen over the top and they were able to get their sugar water supply that way. Here's a picture of the larva, so you might see these guys in your own backyard. This is why it's really important, and you probably heard this in the news, make sure you're getting rid of water, standing water that's in bird baths, kiddie swimming pools, plant holders, anything that can hold water is game for the Asian Tiger mosquito. So what happens is the female will lay her eggs along the sides of any kind of water holding container, tires, anything like that, and then the eggs hatch, the larvae go through five developmental stages called instars, they get bigger and bigger and bigger, they become a pupa and then eventually the pupa will emerge as an adult out of the water. So it's a very short life cycle, and these guys can expand their range very, very fast, they're now found in 40 states in the United States. So I used to study these guys for what mediates competition between the Asian Tiger mosquito and the native tree hole mosquito, because it's the competition with the natives that allow an invasive to get in there and expand its range, and one of the common themes with invasives is that, in addition to competition, one of the things that allows them to expand their range is that they, in their new habitats, they don't face the threats that they did in their native habitats, so they leave behind their natural predators, parasites, diseases, and so for my thesis work, I actually was looking at how escape from a certain gut parasite that this mosquito would normally have back in Asia, called ascogregarina taiwanensis, that by escaping the parasite when it gets to the United States, that gives it an added competitive advantage over the native tree hole mosquito that would be parasitized by its own species of parasite. So we did both lab and field studies to see what would happen when this guy is infected or not infected with its gut parasite, would that give it an advantage over the native mosquito, helping it to outcompete it and therefore spread its range, and in fact, we did find that that was the case. So definitely a concern for humans from a health perspective and concerns from an ecosystem perspective. So if you look at this map right here, what's even scarier is not only is this found in 40 states, but with scenarios of climate change, its range could expand even further, further increasing the potential for transmission of human disease. So here in red were the hotspots for where the Asian Tiger mosquito was found in 1990, so basically all along the equator and its native habitat, and then under climate change scenarios for by 2085 you can see that the range would have greatly expanded all through the world. So this is one example of many of where invasives may be aided by climate change scenarios, which of course might be correlated with human activities. So our next example of an invasive species probably needs no introduction. Most people have heard of the zebra mussels, they're used as a classic example of an invasive species in the United States. So zebra mussels are native to the Black Sea and the Caspian Sea in Ukraine and Russia, and these guys are so easily transported. They were first discovered in the Great Lakes region, Lake Saint Clair and Lake Erie, in 1988, and since then they've just been spreading through water ways throughout the Eastern and Midwest of the United States and here in Texas. So despite being really small, they're normally less than an inch and a half, they use their numbers to spread like crazy, so you can see them coating a ship propeller here, this here is actually a beach in Michigan made of zebra mussel shells, so all that is zebra mussel, not sand. It's just absolutely incredible. So they're definitely ecosystem snatchers, they – in the Great Lakes, they don't have their natural predators that they would've had back in their native habitat in Russia, and so these guys will just take over and the female can actually lay 30,000 to 40,000 eggs per reproductive cycle, so over a million babies can come from a single female each year. It's just absolutely staggering. And so when the hatch and the larvae disperse, they just basically will float until they finally find a substrate to land on. So zebra mussels, because they're so fecund, they reproduce so quickly, they outcompete native mussels as well as clams for space, if you're a clam or a mussel and you can't find a substrate to latch onto, that's the end of you, so that's a major limiting resource for these guys, and they also compete for food. So these, of course, are filter feeders and they'll filter the water and they actually do such a good job of filtering the water that, for example

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clear, there used to be just a six foot visibility in the water, when the zebra mussels came in there, they actually increased that to three feet. So initially that might sound like a good thing, because the water got clearer, but it's actually a bad thing, they snatched the ecosystem because what happened was by clarifying the water, all the bottom dwelling plants, what we would call the macrophytes, were able to grow like crazy because they're getting more light now, and so as they grow, they start competing with each other, they start dying and decaying and that just creates a murky mess on the beaches and also leads to increased bacterial growth in the water, which is called nutrification, and those bacteria can actually rob oxygen from the water, therefore affecting fish and other aquatic organisms. So a chain reaction how these guys affect ecosystems. Also in Lake Saint Clair, they led to the near extinction of the unionid clam, as it's called. These zebra mussels will actually grow on top of clams and other native mussels and just choke them out and kill them. So in addition to the destruction on the ecosystem, these guys have done incredible economic destruction for humans. So just since 1988, they've already caused $5 billion of damage, and $3 billion of that was to power plants, because these guys will just coat whatever they find, so whether it be a pipe or you know, anything, anything that gives them substrate, they will just completely coat and disrupt. So they clog pipes, they get into ships, they have really wreaked havoc on water treatment plants, so lots and lots of economic damage. They're found here in Texas now, so as of 2011, Texas was considered to be infested with zebra mussels. So in 2011, Dallas actually shut down one of its water pipelines because it was so infested with zebra mussels, and that was really bad because it also happened to be a drought year, so that put stress on already stressed resources for water. So the best control for zebra mussels is prevention of their expansion, and so this becomes incumbent on everybody to try to make sure that larvae or adults from one waterway don't get into a new waterway. So there's signs being put up all over the place that are warnings to people who drive boats or watercraft that these zebra mussels like to be hitchhikers, and so it's really important that, say you own a beat, when you've had that boat in an area that has zebra mussels, you wanna make sure that when you take it out, you thoroughly clean it with warm soapy water and you allow it to dry for at least five days, because zebra mussel adults can actually survive out of water for five to seven days, so you want to completely dry it in the sun before taking it into a new body of water that doesn't have zebra mussels so that you can prevent the transmission. Also making sure anything that had water in it, ballast water or anything that had water from the place that had the zebra mussels, all of that's emptied out and dried out before taking the boat into a new area, because the larvae are microscopic and so it might not seem like there's any zebra mussels in that water, but there very well could be. So this is really kind of an all out campaign for each of us to be very careful about transporting the zebra mussel from one area to another. And of course, zebra mussels are edible, but they do advise to not eat zebra mussels because of them being filter feeders, they tend to concentrate environmental toxins and pollutants in the meat. So eating them is probably not a viable option for controls, so really the best thing that we can do is just try to prevent their spread. Boy, 2020 has been interesting, hasn't it? Well, in case it wasn't fun enough, we have another invasive. The murder hornets. Yes, these guys have been in the news and they're called murder hornets because they like to murder honeybees. Now, they're also known as the Asian giant hornet or the Japanese giant hornet, and they are in fact, the largest hornets in the world. They can get up to be two inches long and their stinger is ¼ inch long, so it can actually penetrate somebody wearing bee protective gear. So these guys were actually discovered in the Pacific Northwest sometime between September and December 2019. They're native to Southeast Asia and Southern and Eastern Asia, and these guys are very interesting. Check out their mandibles here, chomp chomp. So these guys are threats to honeybee populations if they were to become established in the United States. A single hornet can kill 40 honeybees per minute, so it actually goes and decapitates them. There's videos online, it's quite a sight to see. So they're threats to the actual hive 'cause if you get even just four individual murder hornets in the hive, they can decimate a honeybee population in a matter of hours, so tens of thousands of bees gone in just a few hours. So there's so far been four sightings between September and December, two in Vancouver, Canada, and four in Washington state, so the Washington Department of Agriculture has been on high alert, they've started an all out campaign to educate everybody and try to get anybody who sees one of these guys to report them so that they can gain a control on them and make sure they don't become established. Murder hornets are not only a threat to honeybee populations and everything that comes with that, so economically and ecologically, but they also can do harm to humans. So, while rare, attacks by hornets have happened, so in China, for example, in 2013, over 1,600 people were injured and 42 people died from multiple stings of these hornets. So it usually takes more than 50 stings to be lethal to a grown human, but it can happen, and somebody who's immunocompromised or a small child can be more vulnerable to the neurotoxin that's in the sting, so it is of concern. Some of the control measures, they have traps, they can poison them, and of course, any nests that they find, they're gonna destroy. These guys usually like to form nests inside burrows that either they dig themselves in the ground or that are already dug for them, like for example by rodents. They also like to burrow into hollow, rotten tree logs, so if anybody finds a nest, you can destroy the nest and that will help control the population. Now, while they're a big threat to honeybees in America, actually in their native Japan, there is a different species of honeybee, the Japanese honeybee, which has a very interesting adaptation to combat these guys. So they'll sit at their nest, and if they detect the pheromone of a murder hornet approaching, they'll all get together and surround the entrance of their hive, and they wait for the hornet to approach, and when the hornet gets there, they actually allow the hornet to go inside and then they all ambush the hornet and form a ball of bees around the hornet and then they start using their flight muscles to shake, and by doing so, as they vibrate their flight muscles, it increases the temperature around the hornet and also increases the carbon dioxide, and that will eventually kill the hornet but not most of the bees, so really interesting. But the bees in North America don't have that adaptation so they're much more vulnerable. Now, while we're worried about a potential establishment and expansion of these guys, for one thing, they can fly up to 60 miles per day at 25 miles per hour, which is really incredible, we're not too worried about them becoming established. So for example, Floyd Shockley is the entomologist at the Smithsonian Institute and said there's nothing to panic about, these guys are not established and they're not likely to become established, but there's always a chance there. However, there are people in Japan that consider these guys to be delicacies, so you can fry them, you can steam them, so there's always that. Murder hornets are pretty scary. They look scary, they decapitate honeybees, destroy whole honeybee hives in a matter of hours, and can harm humans, but as scary as all that is, I don't think they're as scary as this guy, the emerald ash borer. So the emerald ash borer, unlike the murder hornets, is established now in the United States. So he's native to Northeast Asia, and the first population was discovered

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in the state of Michigan, and since then this creature has been expanding its range all through the East Coast, Southeast and even recently discovered in Texas, and it's only a matter of time 'til its range goes even farther than that. So this guy is so scary because his chosen food is the ash tree, and there's several species of ash trees that emerald ash borers will feed on, their preference is for green ash trees followed by black ash trees followed by white ash trees. Ash trees play a critical role in ecosystems, especially riparian habitats, and so with the invasion of these guys, we've seen an incredible overall loss of ecosystem biodiversity in those habitats, so we'll get into that in a little more in a second. Real quickly, just the lifecycle of the emerald ash borer. So again, they're very small, but they detect ash trees and they just go for it. They actually pick up on some of the chemical cues that are emitted from the ash tree, and when a female lands on it, she'll lay her eggs in the crevices of the bark, the babies hatch and those hatchlings kind of burrow in underneath the bark and start chomping, and as they chomp, they start doing damage to the trees. So they burrow in there and they get into the phloem, they start eating away at the phloem and parts of the outer part of the xylem and the cambium of the tree, and you might know that the phloem and the xylem of the tree are the life force, kinda life force highways of the tree. The phloem transports nutrients and the xylem transports water up and down the tree, and so when the larvae of these creatures start eating away at those nutrient and water highways, that tree is a goner. So in the process of eating away, they leave these tracks, so these tunnels are called galleries and so you you can tell a tree has been damaged by emerald ash borers because this is, if you peel up the bark, this is what's left behind, just these highways of tunnels everywhere, these galleries. So this would be a tree of galleries here. The larvae continue to develop, they go through a total four instars, four stages, here's a little larva right there, and incredibly it can take them one to two years to actually emerge as adults from the tree, and when the emerge as adults, they will actually leave behind a little burrow hole, an exit hole as it were, that's shaped like a capital letter D. So if you go and you see an ash tree with capital D shaped holes, definitely call your urban forester right away and let them know, because that is something they're gonna wanna know. There's a big effort for citizen scientists to track all the ash trees in the areas and also survey for any signs of infestation by the beetle. So by destroying the phloem and the xylem of the tree, you can see what the effects are on ash tree stands, so you can see all these dead ash trees mixed in, so about 90% dead right there. So the trees that are most vulnerable to infestation by the emerald ash borer are actually ash trees in urban environments, and that's because it's already well known that boring beetles are especially good at infesting trees that are already stressed out, and urban trees meet that criterion. So urban ash trees tend to be stressed because they're constantly experiencing soil compaction, low soil moisture, pollution, they tend to have lower genetic diversity because they tend to come from stock populations. So for all those reasons, if the emerald ash borer

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into an urban environment and there are ash trees there, there's a good bet those ash trees will die as a result of being infested with the emerald ash borer. Now ash trees in rural areas, especially rural riparian habitats, are especially vulnerable if they're in kind of a monoculture environment where there's just nothing but ash trees around, those that are in mixed forest environments are gonna be much more resistant to infestation by the emerald ash borer. If it's more of a uniform stand of ash trees, that borer's just gonna get in there and absolutely take over. So the emerald ash borer, yes, it definitely destroys ash trees, and in fact, since its discovery in 2002 in America, it's already killed tens of millions of ash trees, and that's incredible if you think about it, but that's not all. It's responsible for overall loss of ecosystem biodiversity, especially in riparian habitats. So studies are being done that are showing exactly what the mechanisms are for the loss of ecosystem biodiversity resulting from loss of ash trees as a result of being infested with the emerald ash borer, and these are really interesting. So when you lose ash trees, ash trees are kind of a key tree in a riparian habitat, when you lose those ash trees you actually get a total changeover in nutrient recycling and the soil nutrient content, and when that happens you're gonna have affects on native plant species, you're gonna lose a lot of those that depend on that certain particular nutrient composition in the soil, and when you start losing those natives, boom, those invasive plant species, rush in. So now you're getting overgrowth of invasive plant species, you've lost the ash trees, so now you're also going to lose the species that are native that depend on the ash tree for food and shelter and things like that, and in general you're just getting a total changeover and in some cases collapse

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ecosystem's biodiversity. Now local and even the federal government is in a mad dash to try to put a stop to the expansion of the emerald ash borer's range. This guy is really a big threat to ecosystems. It's already found in over 30 States as of 2018, and in terms of damage, we're talking in the billions of dollars of economic damage resulting from the emerald ash borer. So control measures are underway and there's nothing that's worked 100% with these guys. One of the primary tactics to try to control the emerald ash borer is to remove trees that have signs of infestation. So they'll basically target a tree, say this one's infested, and target it for removal, sometimes they'll even preemptively remove ash tree to try to slow infestations down and even in some cases they'll deliberately allow an ash tree to become

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monitor the growth of the larvae and then remove the tree before the adults emerge and that kind of allows them to help control it. But tree targeting and removal is probably the primary method right now. Now after removal, sometimes they'll go back and use an insecticide or they'll just apply insecticides in general to target the ash borer, but as we know, the law of conservation of problems says we don't know what other effects in the ecosystem applying insecticides might have. Another tactic is they will put traps up in the canopy because when the adults emerge after one to two years and they're ready to find a mate, they'll go up into the canopy and the males will look for females by sight and so they'll actually go and hang green or purple traps that are often laced with a chemical that is a pheromone or mimics the pheromone of the emerald ash borer, and that will attract the males, and then they can go and check the traps for the presence of males and that helps them track where the infestation is or where the range is expanding. Another tactic that's being used is they went and studied the native habitat in Northeast Asia where the emerald ash borer is from and found that there's different species of parasitoid wasps that will hunt and attack these guys. So a parasitoid wasp, of course, is a wasp that will go and attack and sting a particular host and kinda stun it and then lay its egg on the body of the host, the egg hatches and the larva burrows in and feeds on the carcass, sometimes keeping it alive before it's a carcass, and eventually it dies and then continue to feed on the carcass and then emerges an adult wasp, and so it turns out this guy has several species of parasitoid wasps that are its predators back in Northeast Asia and so they've tried introducing three of those species into Canada and the U.S. as a method of biocontrol for these guys. Two did not become established, one did and has had some success in trying to control these guys, but generally it's used for biomonitoring. So what they'll do is they will tag the parasitoid wasp and allow it to go out and hunt and then come back to its burrow and then volunteer scientists or or citizens will go there and track the wasp as it comes back to its burrow and find out what it's carrying and if it's actually carrying an emerald ash borer, then you know that there's emerald ash borers in the area. So so far that program's not been super successful, but that one species of parasitoid wasp has been established now so it remains to be seen whether it will become more successful in the future. Now again, law of conservation of problems, you've now introduced yet another species into the ecosystem and we don't know what effect it might have on other species that are native. The emerald ash borer continues to expand its range, again it's found in over 30 states right now since 2018, it's moving about 12 miles a year, which doesn't sound like a lot but it is. So in Texas here, it was found starting in 2016 in three counties, so Cass county, Marion county and Harrison county, and in 2018, a 12 year old boy using the iNaturalist app found an emerald ash borer in Tarrant county out near Fort Worth, so shows the importance of citizen science. My students have been working on a project that's gonna become a long term project at Samuell Farm out near Mesquite and Sunnyvale in Dallas county where they're going to be – or they have been and will continue to be tracking ash trees in the area using iNaturalist and checking those trees every few months for signs of infestation of the emerald ash – and this is very timely, because just a few days ago, on May 18th, 2020, a local paper in Denton reported that they have now found infestations of the emerald ash borer there in Denton in North Texas. So it turns out, they're not sure how the borer got to the United States in the first place, but there's a good bet that it was probably on packaging crates that came over from China. However, now that it's here they think one of the primary ways it's able to expand its range is by human activities, especially humans transporting firewood, that could be transporting firewood from campsite to campsite, or you know, chopping down ash trees in one place and then selling it for firewood or transporting it for firewood out of state. So what you can do to help curb the emerald ash borer's infestation, be very very careful about firewood. Don't transport it out of a particular county or out of the state, constantly inspect it. If you have ash trees in your yard, constantly inspect them, you want to look for any signs of dead branches that come out of the top of the tree or leafy shoots coming out from the bark itself from the trunk. What the tree will do if it gets infested, it'll start going crazy and trying to send new shoots out and just try to do whatever it can to survive. Of course, you can always – if you peel back some of the bark, if you see galleries, you know what we have here or something that looks like that, definitely you wanna report that to the Texas Department of Agriculture or your local urban forester. Of course, if you see the D shaped exit holes, you wanna report that, yellowing of the leaves, so these are all signs that the tree may be infested. Another sign to look for is a lot of woodpecker holes in

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so turns out woodpeckers will eat the larvae of the emerald ash borer, and so if the tree's infested, the woodpecker might just be making all sorts of different holes in there to try to capture as many larvae as possible, so it doesn't mean that if there are woodpecker holes that there are emerald ash borers there, but it's a sign that could indicate that. So do your part to try to curb the spread of this emerald ash borer, it devastates riparian habitats, and as pretty as it is, we don't want it in the United States

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okay, so I think you can hear me now, right? All right, so I'm gonna really quickly share some questions for thought and just to see how you did on learning some of these concepts, and we'll go over the answers and then I'm gonna give it back to Georgeann. So let me really quickly share this and open up the PowerPoint. Okay, so first question here, after climate change and habitat destruction, invasive species are the biggest threat to the world's biodiversity. So you guys said – actually, nobody responded to that one. Oh, true. Lucinda Gonzales says true. Second question, what has been the cost of zebra fish to the U.S. economy since its introduction into the U.S. in 1988? And so for that one someone says C, and that's correct, probably 'cause I just accidentally showed you the answer. That's right, $5 billion, no, 'cause you guys learned that. #3, all species are introduced into new habitats that they're considered to be invasive species. Someone says false, that is correct, so not all invasives that are introduced become – or not all – all introduced are not invasives, but all invasives are introduced. #4, which

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help invasive species to outcompete native species and their ranges? Escape from their natural predators, competitors and parasites, tolerance for pollution, variable environments and human activities, rapid reproduction growth, or all of the above? So Timothy Chan, correct, all of the above. And finally, which of the following species is the most likely to be an ecosystem snatcher in the U.S.? The murder hornet or the emerald ash borer? So you guys are correct, the emerald ash borer. Stop sharing there. So that's it, thank you so much guys, and if you have any questions, you can always reach me via email at brieday@dcccd.edu.

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