Wildlife Center Classroom Series Invasive Species 101 Wednesday June 14, 2017 Welcome to this month s Wildlife Center Classroom Series: Invasive Species 101! If this is your first time watching the Critter Cams or being a part of the moderated discussion, let us know in the comments let s jump right in! Comment From Jen First time for both! Great to have you with us, Jen! Invasive species have become a better-known environmental issue during the past few decades, and
with good reason. The National Wildlife Federation (NWF) estimates that approximately 42% of Threatened or Endangered species at risk primarily due to invasive species. Yikes! To understand exactly what we re dealing with here, we need to first define what an invasive species actually is; however, the definition itself presents a bit of a gray area. Comment From ʕ ᴥ ʔ dancelady ʕ ᴥ ʔ Starlings? I used to get these in my house all the time through the fireplace. Trying to catch them was a scene, really difficult to get. Yep -- that's a classic example. We'll talk about European Starlings later on! Some biologist question whether a native species can be considered invasive, so there are two slightly differing definitions. The first and most widely accepted applies to non-indigenous (or non-native ) species: An invasive species can be any kind of living organism (to include vertebrates, invertebrates, plants, fungus, bacteria even an organism s seeds or eggs) that is not native to an ecosystem and which causes harm. NWF The second definition includes the first, but broadens the boundaries to include indigenous (or native ) species along side the non-native ones. Deer, for example, are native to the United States, but are overpopulating their native zones and spreading into areas where populations haven t been observed in the past. The exact type of harm an invasive species can cause is quite varied. They can harm native animals, the environment, the economy, and even human health. We ll explore some specific examples a little later on in the discussion. This map created by The Wildlife Society highlights areas that have become (or already are) mostthreatened by invasive species:
Comment From Jen WOW! While there are a huge variety of living organisms with the invasive label, they all share four key traits. 1. They grow and reproduce quickly 2. They spread aggressively 3. They tend to prey on native species 4. They benefit from an absence of natural predators in new areas In short, they alter the way an ecosystem works in a negative way. It s also important to remember that an invasive species doesn t have to come from another country! A good example is Lake Trout native to the Great Lakes. They re all-american, but are considered invasive in Yellowstone Lake in Wyoming because they outcompete the native Cutthroat Trout for resources like food, space, and shelter. When a new and aggressive species is introduced, they immediately bring with them both direct and indirect threats to an established ecosystem. Direct threats include things like preying on native species, out-competing native species, causing or carrying diseases, and even preventing native species from reproducing or killing their young.
Indirect threats are a little less obvious at first glance, but are just as important. They include things like changing the overall structure of the food web, decreasing biodiversity, altering ecosystem conditions (like the chemistry of the soil, or intensity and frequency of wildfires), and damaging infrastructure (like artificial waterways and pipelines, roadways, etc.). It s estimated that invasive species cost the U.S. $138 BILLION dollars a year to control and manage. Comment From BarbG WOW lots of money Yep, you read that correctly -- billion with a "B". So, how do invasive species "invade" an area in the first place? Unfortunately, they primarily spread by human activities, often (but not always) unintentionally. Let s take a look at three different invasive species, how they ve been spread, and the impacts of their introduction to new ecosystems. Case study: The Quagga Mussel, Dreissena bugensis Not a very intimidating looking animal, is it? Looks can be deceiving Quagga Mussels, and the closely related Zebra Mussel, have become one of the most destructive invasive species in recent history. Comment From Cathy in Nevada Is that aka zebra mussle?
Different species, but very similar in appearance and life cycles. Comment From BarbG Living in Michigan, we hear a lot about these From their native range in Ukraine, the free-floating larval form of these mussels were unknowingly transported across the Atlantic Ocean in the ballast tanks of large ships. A ballast is a compartment in large ships that hold water in order to stabilize it in rough seas. Ballast water is drawn in at port before departure, and purged upon arrival. After being dumped out of the ballast tanks of cargo ships arriving from Europe into the Great Lakes in the late 1980 s, they have spread dramatically in the same way being transported in the hulls of ships and recreational boats. This USGS map shows known locations of both these mussels in 2015: Comment From Guest what about cats? can they be considered an invasive species? (outdoor cats, that is) Yes, feral cats are considered to be an invasive species!
Comment From Cathy in Nevada Have they learned to "poison" the water before emptying the tanks? Unfortunately, poisoning ballast water would harm all the wildlife and ecosystem factors in bodies of water where it would be purged, and hasn't been considered as a management tactic. Quagga Mussels (and Zebra Mussels) can attach to almost any hard surface -- they clog water intake and discharge pipes, attach themselves to boat hulls and docks, and they even attach to native mussels and crayfish. That used to be a shoe! Comment From Jen WHOA!
Comment From Cathy in Nevada Thought something like changing salinity to kill invasive species, then resalinize it before emptying tanks Oh, I see! I didn't come across any idea like that when I was researching for this class, but it's an interesting idea...as a fresh water species, they would certainly be affected by salt water...interesting! Comment From Deb in PA Hello Alex! Our biggest problem in this area is House Sparrows. They go into Bluebird Houses and kill the adult and babies. It's so frustrating... Yep, another invasive bird species that outcompetes the natives. Not only do Quagga Mussels out-compete native species for space, they reproduce at an explosive rate. As filter feeders, they strain algae and plankton from the water high populations of the mussels can transform bodies of water into an ecological dead-zone. With few natural predators and the ability to close their shells and pass through digestive systems unharmed these mussels are almost impossible to remove once they ve infested an area. The best method of removal is prevention! Ways to prevent accidentally transporting them are simple and inexpensive: washing and completely drying boats and other equipment, removing any aquatic plants or mud, and throwing away unwanted fishing bait in the trash. Comment From Melinda in NC I saw a study on Lionfish once. Never thought about how invasive they are. Invasives come in all shapes and sizes, it's true. On to the next case study! Case study: Emerald Ash Borer, Agrilus planipennis
Comment From Lynda in AZ In regards to the mussel problem, there is a radio ad that basically says "Don't move a mussel" where they remind boaters to be careful with their boats (with the Colorado River right here, boating and PWC are BIG!) (Fun fact: I used to work as an Aquatic Nuisance Species Park Ranger in Colorado, our motto was "Spread the message, not the mussles.") The Emerald Ash Borer (EAB), originally from eastern Russia, northern China, Japan, and Korea, is an insect that had never been observed in North America before June of 2002. While biologists aren t exactly sure how they got to America, it s most likely that they came in ash wood used for packing and shipping pallets and containers. In 2002, the EAB was initially found in six counties in southeastern Michigan. Today, the EAB has spread to almost all of the East Coast and Midwest, including several Canadian provinces:
Comment From BarbG another big problem in Michigan Yep -- seeing a theme? Lots of shipping ports and global trade routes near water ways... Comment From Jen We are losing so many trees to this one! When this insect burrows beneath the bark of an ash tree to lay it s eggs, the newly-hatched larvae eat and destroy water and nutrient conducting tissues -- effectively killing an otherwise healthy tree in as little as one year. Comment From BarbG lots of trees affected Alex Wehrung, WCV Like the Quagga Mussel, though, this insect is the most-widely spread by people! EAB s usually only fly within a mile from the tree they initially emerged from. However, when people move infested trees to nurseries, or transport infested firewood to new areas, they can spread very quickly. Comment From CarolinaGirl Been lurking and learning. There must be a huge list of invasive, animals and plants. With world travel what it is today, that list will surely become longer as things hop on for the ride.
Hey, CarolinaGirl! You're right -- the list is huge, especially when you include plants. In fact, the EAB is considered to be the most destructive forest pest ever seen in North America. The solution? Once again, prevention. You ve probably seen signs like these at campgrounds around the country: Many agencies and universities are working together to educate citizens about the identification of ash trees and the EAB, and many state and federal agencies have programs in place to help restore the urban forest in cities that sustained heavy EAB damage. Comment From BarbG All campgrounds in Michigan have signs like that too On to our final case study...
Case study: The European Starling, Sturnus vulgaris Comment From ʕ ᴥ ʔ dancelady ʕ ᴥ ʔ It seems like a small price to pay if you have a business, just like killing eagles -- should be a much bigger and more serious penalty? I'm not sure about specific laws for each state, but I know from working with the Colorado Department of Parks & Wildlife that knowingly transporting invasive species can result in some very large fines, and even jail time for repeating offenders. The European Starling is a well-known species throughout the birding world, and a very common sight throughout the U.S. It s origins as an invasive species are a bit different compared to our previous case studies, though! TIME magazine explains their history in this 2010 article: In 1890 New York drug manufacturer Eugene Schieffelin released some 60 European starlings in Central Park. His dream was to introduce every bird mentioned by Shakespeare into North America an intent that proved to be more Hitchcock than Bard. Schieffelin hoped the songbirds would prosper in their new home in ways the skylarks and song thrushes had not, and they certainly did.
Since 1890, those 60 European Starlings have reproduced and spread from Central Park to the entire continental U.S.: These birds can roost in flocks of up to one million individuals! Not only do they outcompete native species, they can devour literal tons of crops in a single day, and their droppings are thought to be vectors of several infectious diseases. Because these birds as so well-stablished and wide-spread, removal is virtually impossible. Various control methods have been tried such as placing protective netting over crops, poisoning and shooting, and eliminating nest sites and food and water sources (as invasive species, these birds are not protected by the Bird Migratory Act). A 2001 Columbia University study proved that a possible long term solution, particularly for reducing
numbers of starlings in areas where they are competing for nest sites with cavity nesters, might be to provide a large number of nest boxes away from the immediate areas of the cavity nesters, and then remove eggs or young. Comment From ʕ ᴥ ʔ dancelady ʕ ᴥ ʔ Have you any idea how they can flock massively and swerve so suddenly, all together, nobody in charge, but still like a practiced flow? I know it is too much to admire, but still kinda amazing. Reminds one of a school of fish, doesn't it? While it can be easy to feel like there's no hope of ever truly solving the issue of invasive species, it s not all doom and gloom! The solutions to help curb the spread of invasive species are inexpensive, easy to do, and well within the average person s capabilities. Comment From PaulaR there are some good scientific studies now on "murmurations" of starlings...they watch each other, paying most attention to the bird on each side of them rather than ahead or behind... Plant native plants and remove any invasive plants in your garden or yard. There are a huge number of native alternatives to common exotic ornamentals, and our local pollinators will thank you. Learn to identify invasive species in your areas. Report any sightings to local natural resource management agencies! Regularly clean gear like boots, tires, or any equipment you use outdoors. When camping, only use or buy firewood from within 30 miles of your campsite. Comment From Cathy in Nevada Like helping the eagles, EDUCATION! Exactly! Help spread message and knowledge about invasive species to friends and family. For anyone interesting in learning more about what species might be considered invasive in your area, I highly recommend checking out the US Department of Agriculture s online National Agricultural Library page:
https://www.invasivespeciesinfo.gov/unitedstates/state.shtml Just click on your state, and a number of educational resources are available. It's a great tool for learning! That s all for the Classroom Session today, everyone, thanks for joining in on the discussion! I ll be online for a few more minutes to answer any questions before logging off. Have a great day!