One of the topics we discussed in science at Pathfinder this week was how one little act can create a chain-reaction. One example of this is when the people of Borneo got rid of malaria-carrying mosquitos using a man-made chemical. The chemical, DDT, killed not only the mosquitos, but also parasitic wasps that killed roof-eating caterpillars, and poisoned the geckos that ate the mosquitos, which, in turn, poisoned and killed the cats that eat the geckos. Consequently, the mice and rat population grew, spreading two new viruses. As a solution, cats had to be parachuted into Borneo. The domino affect story shows how one thing in this story, DDT, can lead to bigger things like the two new viruses.
Sea otters provide another example that shows that “everything is connected”, called a trophic cascade. A trophic cascade is when the addition or subtraction of a top predator causes big changes in the ecosystem. Sea otters play a vital role to keep sea urchins in check by eating them. Kelp forests that have sea otters are usually healthy, but kelp forests without healthy sea otter populations are unhealthy and are mostly now “urchin barrens” because too many urchins eat all of the kelp.
My last example is the African Elephant. In very big habitats, where they can migrate, elephants’ feeding habits create a balance between forest and savannah by taking down trees so other things can grow. But, in smaller ranges, because of habitat fragmentation, they can’t migrate and will completely devastate forested areas, leaving nothing but shrubbery.
A Plea from the Short-Eared Owl
Co-written by Harrison Jeffries
Dear Mrs. Cuttatree,
I am a short-eared owl, also known as asio flammeus. My name comes from small tufts on my head, right where some other animals’ ears might be. Other creatures with these “ears” are long-eared owls and great horned owls. You can tell me apart from them because my tufts are much shorter. I am about 13-17 inches tall with a wingspan of 33-43 inches. My other distinctive features include my boomerang-like wings, giving me a moth-like flight-pattern, and a white facial disc. Unlike most owls, I would rather get up in the day than at night. In fact, I am the most diurnal owl in the world, but I do sometimes hunt at night. I’m a unique species and a pretty cool guy to have around… at least until you build that resort.
You see, I live in tundras, marshes, and other flat habitats, but during mating season, after a long migration, I sometimes roost in trees, which you intend to chop off from the roots! Now, I don’t need a tree. I make my nest on the ground, but that is right where you intend to build that silly resort. Although I have a large range, spanning through most of North America and some of South America, I’m in trouble in most of my range and considered endangered in many states, including Michigan. While I only come to Michigan for breeding, my children depend on a wide stretch of open space and grasses to grow-up in. Did you know that a female short-eared owl can lay 4 to 9 to even 14 eggs? We short-eared owls are extremely devastated by loss or fragmentation of habitat because we need a big space to live in. One of the reasons that I and other short-eared owls should not go extinct is because we mostly eat voles, which you consider pests because they can kill infant trees, shrubs, and other plants. If you think the voles are bad now, just wait until us short-eared owls are gone. The vole population will grow much bigger- I wonder who’s to blame? Now that you heard my plea, can you please consider helping us by canceling your construction on the Uppity Resort?
The short-eared owl