Decomposers
Decomposers are vital parts of our ecosystem in Bridle Trails State Park because soil is such an important part of our park! Healthy soil is composed of five things: water, air, minerals, humus (not hummus, but broken down material from rotting plants and animals, aka compost), and organisms that work as decomposers – breaking down the humus and create more vitamins and nutrients. Another way to remember these organisms is by remembering the FBI. No, not that FBI.
This FBI:
Fungi: mushrooms and molds
Bacteria: microscopic good (and occasionally “bad”)
Invertebrates: slugs, worms, insects, and other arthropods
Check out this fun song by the Banana Slug String Band about the FBI !
Decomposers are one of the most important things in our forest and forests around the world. If we did not have them, our planet would be covered in deep piles of leaves, trees, and every other living material! A forest drops about 6 inches of leaves every fall. In 1000 years we would have a pile as deep as the space needle rather than the 1 inch of healthy soil we end up with in that time. Decomposers create soil and help recycle nutrients.
Types of Slugs
In the Pacific Northwest, the banana slug is a sign of a healthy forest. Slugs are a great example of the difference between native, introduced, and invasive species.
Banana slugs, the ones that are yellowish with spots like a rotting banana (usually), are native to the northwest.
Leopard slugs, with spots like a leopard, are introduced to the northwest – an annoyance to gardeners but not necessarily taking over.
European slugs, the brown or black slugs with deep grooves on its back, are invasive and are slowly out competing the native banana slugs.
Slugs get a bad rap because the two introduced species eat plants that gardeners grow. They hunt out the delicious plants that we also like to enjoy such as lettuce, peas, and broccoli. Banana slugs on the other hand are detritivores and only eat material that is 3D (dead, down, and detached) and prefer to live in moist cool northwest forests. They are a sign of a healthy, happy forest. See how many you can find on your next walk!
Parts of a slug
Foot: the slug body is called a “foot” that moves in waves
Mantle: the fleshy head covering that protects important body parts
Mouth: slugs and snails eat with a radula that is a tongue covered with up to 27,000 teeth (more than a shark!)
Pneumostome: the breathing hole on the right side of the mantle
Eyes: located at the ends of the tentacles. Slugs can see about as much as if you closed your eyes, pointed your face towards a light, and moved your hand back and forth in front of your face!
Nose: slugs use the shorter tentacles for smelling and feeling
Since slugs don’t have shells like snails to protect them, they need to stay WET.
They
lose moisture through their mucus, which does 5 things:
Provides a “carpet” for movement by working as a lubricant and adhesive
Protects the foot from sharp materials
Provides moist surface for oxygen to enter the body
Makes it harder for predators to capture
Can be toxic to some animals (makes human skin numb)
More information:
Learn how to draw a banana slug from a Burke Museum employee here!
Check out these YouTube songs by the Banana Slug String Band: “Decomposition,” “FBI,” and “Banana Slug.”
Learn more about decomposers or do a banana slug trivia on Nature Vision’s 50 Days of Discovery.
For more information on slugs, check out The Secret World of Slugs and Snails: Life in the Very Slow Lane by David G. Gordon.
Check out this blog for great photos of banana slugs and a review of information.
Photo credits: Mother Nature Network, Wikipedia.