Speaker 1: Welcome to Brainstuff, a production of iHeartRadio, Hey Brainstuff Laurin
Speaker 1: Vogel bomb here. Nutrients, water, and living space are some
Speaker 1: of life's basic needs, so anything that alters their distribution
Speaker 1: is going to be a key factor in our struggle
Speaker 1: for survival. A change the waterways, the landscape, or the
Speaker 1: availability of food, and an entire ecosystem can be reshaped.
Speaker 1: Certain species wield that power to great effect. One of
Speaker 1: the most fascinating topics in biology is the role of
Speaker 1: ecosystem engineers. These are organisms that either directly or indirectly
Speaker 1: alter their physical surroundings in ways that have major impacts
Speaker 1: on the livelihood of other organisms. Take, for example, the
Speaker 1: American alligator. Out in the wild, these big reptiles like
Speaker 1: to make their own swimming pools. Using their snouts and claws,
Speaker 1: they create massive trend known as gator holes in the
Speaker 1: limestone around Florida's Everglades. In short order, they flood with water.
Speaker 1: They also tend to remain full of water even well
Speaker 1: into the dry season, a time when standing water can
Speaker 1: be scarce for other life forms. A gator hole can
Speaker 1: provide a badly needed oasis of frogs and turtles move
Speaker 1: into these convenient little ponds while plants around their rims,
Speaker 1: attracting all kinds of insects. So, as unlikely as it
Speaker 1: may sound, Florida alligators are environmental stewards. They create brand
Speaker 1: new homes for their neighbors and in the process, strengthen
Speaker 1: the biodiversity of the everglades. Other ecosystem engineers leave different marks. Today,
Speaker 1: we're looking at a few that reshape rivers, link ponds together,
Speaker 1: and transform mangrove creeks. Map makers of the world. You'll
Speaker 1: want to keep your erasers handy when these beasties come to town.
Speaker 1: First up beavers. The term busy as a beaver really
Speaker 1: should be considered high. Beavers are hard working rodents. A
Speaker 1: lone one can cut down up to two hundred trees
Speaker 1: in a single year. Famously, they build sturdy homes or
Speaker 1: lodges for themselves out of branches, mud, and other materials.
Speaker 1: They can also make their own large scale ponds by
Speaker 1: damming streams, and this works by creating a backlog of
Speaker 1: water upstream of the dam. The resulting pond not only
Speaker 1: gives beavers a place to build their lodge, it also
Speaker 1: affords easy access to surrounding trees. Often around a foot
Speaker 1: or a third of a meter, of water covers the
Speaker 1: bases of nearby pines and hardwoods that once stood on
Speaker 1: dry ground. As a result, beavers can swim right up
Speaker 1: to these trees. They also like to dig canals that
Speaker 1: branch out of the new ponds, penetrating deep into the
Speaker 1: local forest. These new wetlands provide homes for smaller animals
Speaker 1: like amphibians. Plus, the dams make great natural filters, a
Speaker 1: blocking excess nitrogen from our creeks and streams. However, all
Speaker 1: of the side effects are positive. When a beaver dam fails,
Speaker 1: it's liable to flood towns or farms. The aftermath can
Speaker 1: be expensive. In the southeastern US alone, these floods are
Speaker 1: responsible for an estimated twenty two million dollars a year
Speaker 1: in damages to the timber industry. It's not surprising, then,
Speaker 1: that many people view beavers as pests. If you have
Speaker 1: a beaver problem, do know that humane solutions are out there.
Speaker 1: Next up the adorable yet terrifying hippopotamus. Put a group
Speaker 1: of hippos and a floodplain with lots of nice, soft soil,
Speaker 1: and they'll start reconfiguring the turf. That's because hippos have
Speaker 1: unique skin that needs to be kept wet for most
Speaker 1: of the day or they'll become dehydrated, so they plow
Speaker 1: through the reed beds that ring rivers and lakes, creating
Speaker 1: deep wallows of water and mud that keep them cool
Speaker 1: during hot days. They're too heavy to float or swim,
Speaker 1: so they reshape the soil bed beneath the water to
Speaker 1: walk along it, the tops of their heads poking out. However,
Speaker 1: these wallows don't offer much in the way of food,
Speaker 1: so at night hippos leave their comfy wallows to go
Speaker 1: grazing on dry land, returning before the sun. That daily
Speaker 1: coming and going creates deep depressions in the soil near
Speaker 1: bodies of water, which in turn become channels worn down
Speaker 1: over time. These footpaths can be as much as sixteen
Speaker 1: feet that's five meters wide, and just like gator holes,
Speaker 1: they're quick to fill up with water. Oh what's more,
Speaker 1: hippo highways linking ponds and streams to big rivers can
Speaker 1: also be established. If the area should flood, these connection
Speaker 1: points may become an outlet for surging water. They also
Speaker 1: enable swamplands to expand and under the right circumstances, The
Speaker 1: trench like trails can divert a great deal of sediment
Speaker 1: from rivers into ponds. And that's not all that hippos
Speaker 1: are doing as they go about their business. Pun intended
Speaker 1: fifteen analysis determined that hippo dung is an important source
Speaker 1: of nutrition for at least some of the fish and
Speaker 1: insects that share the animal's native range. Never underestimate the
Speaker 1: power of poop. However, for their size, hippos don't actually
Speaker 1: eat a lot, only about one to one and a
Speaker 1: half percent of their body weight every day. Large cattle
Speaker 1: eat more like two and a half percent, and African
Speaker 1: elephants can eat over four percent, which is no joke
Speaker 1: when you weigh some seven tons. On a typical day,
Speaker 1: an adult elephant will spend twelve to eighteen hours eating,
Speaker 1: which is vital to the ecosystem. Elephant dung is a
Speaker 1: nutritious fertilizer for the soils of Africa. It's also a
Speaker 1: vehicle by which many seeds are dispersed. Furthermore, by knocking
Speaker 1: down trees and eating shrubs, these colossal animals convert forests
Speaker 1: into grasslands, and a two thousand and nine study published
Speaker 1: in the journal Bioscience revealed even more about the transformative
Speaker 1: powers that African elephants have over their habitats. Sort of
Speaker 1: similar to hippos, Elephants are great at building water channels.
Speaker 1: The test herbivores cover the same land routes over and
Speaker 1: over again as they go about finding food and water,
Speaker 1: making trails in the process. Sometimes multiple generations of elephants
Speaker 1: will reuse the exact same footpaths. As time goes by,
Speaker 1: the animals compress the soil, turning their walkways into trenches,
Speaker 1: and when elephants move back and forth between bodies of water,
Speaker 1: their sunken trails become nice conduits. Thus, rivers or ponds
Speaker 1: that were once isolated can be merged via elephant made canals,
Speaker 1: providing inroads for other wildlife to travel. And another study
Speaker 1: of Asian elephant trails in Thailand found that these paths
Speaker 1: can divert monsoon run off into local streams, preventing flooding.
Speaker 1: But enough of mammals and reptiles. A number of crustaceans
Speaker 1: are great diggers, including fiddler crabs, which shelter in tunnels
Speaker 1: measuring up to three feet or more in that's about
Speaker 1: a meter. The holes are quite a construction project. Given
Speaker 1: the fact that most fiddler species are less than two
Speaker 1: inches or five centimeters wide, then there are the various
Speaker 1: species of burrowing crabs of the mangrove swamps and salt
Speaker 1: marshes of the world. The tunnels that these small crabs
Speaker 1: build are liable to weaken the surrounding turf. On mangrove
Speaker 1: swamp shorelines, this has the effect of widening tidal creeks,
Speaker 1: whose mud and clay based banks are rendered more vulnerable
Speaker 1: to erosion by the digging invertebrates. They may also play
Speaker 1: a key role in aerating the marshy soil and kicking
Speaker 1: up nutrients from the beds, and that's just part of
Speaker 1: the story. Because burrowing crabs have such a profound effect
Speaker 1: on sediment composition, their tunnels can also cause completely new
Speaker 1: creeks to form within these mangrove systems, and all of
Speaker 1: this further impacts the plants and other animals that live
Speaker 1: around those environments. Those tiny crabs change how microorganisms in
Speaker 1: places can grow, which changes what foragers and predators come
Speaker 1: to the area. Just another example of how small actions
Speaker 1: can add up to huge effects. Today's episode is based
Speaker 1: on the article Eco engineers five animals that can reshape
Speaker 1: Earth's waterways on how stuffworks dot Com. Written by Mark Vancini.
Speaker 1: Brain Stuff is production by Heart Radio in partnership with
Speaker 1: how stuffworks dot Com and is produced by Tyler Klang.
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