The little known invasive threats to area wetlands

The Seeley-Swan area boasts an exceptional number of wetlands and variety of wetland types, from the giant lakes where loons and eagles chase fish to the wet meadows amongst the forests where rare plants grow and great gray owls hunt voles and pocket gophers. Wetlands are biodiversity hotspots, containing the greatest abundance and diversity of organisms of any habitat type in Montana. Wetlands also greatly benefit humans through storing and filtering the water we use, controlling the spread of wildfires and supporting local economies through recreation.

The wetlands in the Seeley-Swan area are quite resilient to change but they are not immune to all impacts. One of the biggest threats to these ecosystems are species people purposefully or accidentally introduce to the area that did not evolve here.

We have all heard about things like spotted knapweed and zebra mussels. These are invasive organisms that can reach shockingly high densities in areas they infest, most often with major negative impacts on almost every other plant and animal in the infested area. These invasive species can become so dominant because other species that compete with or eat them in their native environment are not present in the ecosystem they have infested. In other words, they are thrown into a system with no checks and balances on their spread.

Some invasive species have already gained a foothold in the Seeley-Swan. A lot of time, money and energy are now put towards attempting to control those infestations. But there are still plenty of other invaders that could show up and could be catastrophic. All it would take is a few careless pet owners releasing their unwanted pets, or a single "bucket biologist" (a person who illegally introduces a species to an area).

I would like to highlight three not-so-well-known invasive species that have me worried about the future of the incredible wetlands of the Seeley-Swan. Because the wetlands are so widespread and well-connected in this area, if these invaders get established they can quickly spread through so many lakes, backwaters, sloughs and ponds that there is almost no chance of containing them. Those invasive species are the snapping turtles, American bullfrogs and pond sliders.

Snapping turtles are native to eastern Montana but are non-native in the western part of the state. When they reach adulthood there is almost nothing that eats them but snapping turtles will eat anything they can snap at including frogs, snakes, fish, baby waterfowl and even small mammals. These monstrous turtles can get up to 70 pounds! Compare that to our native painted turtle coming in at around one pound.

Bullfrogs are even scarier than snapping turtles because they reproduce like crazy and can take over very quickly. A single female can lay close to 50,000 eggs compared to a few hundred or thousand eggs laid by native frogs. Just like snapping turtles, their diet is only limited by what they can fit in their mouths, so snakes, lizards, baby birds, small mammals, crayfish, bats and other amphibians are all edible to bullfrogs. In areas of Montana where bullfrogs have become established, biologists generally consider it a lost cause to try to control them. They just breed too quickly and spread too rapidly.

Pond sliders are small turtles often kept as pets that are bold and aggressive compared to native painted turtles. They will outcompete the native turtles for food, nest sites and basking space. They may entirely replace them in wetlands where they become established. Pond sliders are a common turtle pet but are so invasive it is now illegal to own one without a permit.

Because none of the native wetland wildlife in the Seeley-Swan evolved with these three invasive species around, they aren't aware of them as potential competitors or predators. So, the native wildlife have not developed effective ways to avoid or defend against the invaders. In such a situation the invasive species can run amok to the detriment of entire ecosystems.

Unfortunately, people are the reason these creatures have entered our wetland ecosystems elsewhere in the state and if they come to the Seeley-Swan it will almost certainly be the same story. Fortunately, we are also the best defense!

If you care about the wetland ecosystems of the Seeley-Swan, please consider taking time to learn how to identify snapping turtles, bullfrogs and pond sliders, and then be on the lookout for them. I highly recommend the Montana Natural Heritage Program website (mtnhp.org), where you can find accounts of these three species and learn how to identify them. If you see one of these three species in the Seeley-Swan, please report it to FWP immediately.

The Seeley-Swan area remains such a biodiversity powerhouse because of careful fish and wildlife habitat management by agencies, private landowners and non-profit organizations. Equally as important, the people that live and recreate in the Seeley-Swan have fallen in love with the area and work to protect it. All of us need to take some responsibility to keep an eye on it. Watching out for bullfrogs, snapping turtles, and pond sliders and reporting them as soon as you see them is a great way to have a huge positive impact. All you have to do is get outside and pay attention to the critters that make these wetlands their homes. Heck, many readers are probably already doing that all the time, so thank you in advance for your help!

In addition to the Seeley-Swan area, if you see a snapping turtle anywhere in the Bitterroot or Blackfoot River drainages, or anywhere in the Clark Fork River drainage upstream of the confluence with the Flathead River, please contact Torrey Ritter at 406-381-2339, or at torrey.ritter@mt.gov as soon as possible. Also, if you have acquired baby snapping turtles, pond sliders or bullfrogs as pets, please do not release them into the wild. If you are not sure what to do with them, please contact me (Torrey). Thank you!