1 00:00:01,840 --> 00:00:07,960 Speaker 1: Welcome to Brainstuff, a production of iHeartRadio, Hey Brainstuff Laurin 2 00:00:08,000 --> 00:00:13,280 Speaker 1: Vogel bomb here. Nutrients, water, and living space are some 3 00:00:13,480 --> 00:00:17,440 Speaker 1: of life's basic needs, so anything that alters their distribution 4 00:00:17,800 --> 00:00:19,960 Speaker 1: is going to be a key factor in our struggle 5 00:00:19,960 --> 00:00:24,000 Speaker 1: for survival. A change the waterways, the landscape, or the 6 00:00:24,040 --> 00:00:27,920 Speaker 1: availability of food, and an entire ecosystem can be reshaped. 7 00:00:29,600 --> 00:00:33,760 Speaker 1: Certain species wield that power to great effect. One of 8 00:00:33,800 --> 00:00:36,640 Speaker 1: the most fascinating topics in biology is the role of 9 00:00:36,720 --> 00:00:42,400 Speaker 1: ecosystem engineers. These are organisms that either directly or indirectly 10 00:00:42,479 --> 00:00:46,000 Speaker 1: alter their physical surroundings in ways that have major impacts 11 00:00:46,040 --> 00:00:50,519 Speaker 1: on the livelihood of other organisms. Take, for example, the 12 00:00:50,560 --> 00:00:54,680 Speaker 1: American alligator. Out in the wild, these big reptiles like 13 00:00:54,760 --> 00:00:58,720 Speaker 1: to make their own swimming pools. Using their snouts and claws, 14 00:00:58,800 --> 00:01:01,640 Speaker 1: they create massive trend known as gator holes in the 15 00:01:01,640 --> 00:01:06,559 Speaker 1: limestone around Florida's Everglades. In short order, they flood with water. 16 00:01:07,360 --> 00:01:09,920 Speaker 1: They also tend to remain full of water even well 17 00:01:09,959 --> 00:01:12,759 Speaker 1: into the dry season, a time when standing water can 18 00:01:12,800 --> 00:01:16,800 Speaker 1: be scarce for other life forms. A gator hole can 19 00:01:16,840 --> 00:01:20,400 Speaker 1: provide a badly needed oasis of frogs and turtles move 20 00:01:20,440 --> 00:01:23,760 Speaker 1: into these convenient little ponds while plants around their rims, 21 00:01:23,800 --> 00:01:27,720 Speaker 1: attracting all kinds of insects. So, as unlikely as it 22 00:01:27,760 --> 00:01:32,919 Speaker 1: may sound, Florida alligators are environmental stewards. They create brand 23 00:01:32,959 --> 00:01:36,360 Speaker 1: new homes for their neighbors and in the process, strengthen 24 00:01:36,440 --> 00:01:43,199 Speaker 1: the biodiversity of the everglades. Other ecosystem engineers leave different marks. Today, 25 00:01:43,280 --> 00:01:46,440 Speaker 1: we're looking at a few that reshape rivers, link ponds together, 26 00:01:46,640 --> 00:01:50,280 Speaker 1: and transform mangrove creeks. Map makers of the world. You'll 27 00:01:50,280 --> 00:01:53,400 Speaker 1: want to keep your erasers handy when these beasties come to town. 28 00:01:55,280 --> 00:01:58,840 Speaker 1: First up beavers. The term busy as a beaver really 29 00:01:58,880 --> 00:02:03,360 Speaker 1: should be considered high. Beavers are hard working rodents. A 30 00:02:03,480 --> 00:02:06,040 Speaker 1: lone one can cut down up to two hundred trees 31 00:02:06,080 --> 00:02:09,720 Speaker 1: in a single year. Famously, they build sturdy homes or 32 00:02:09,840 --> 00:02:13,239 Speaker 1: lodges for themselves out of branches, mud, and other materials. 33 00:02:13,840 --> 00:02:16,200 Speaker 1: They can also make their own large scale ponds by 34 00:02:16,280 --> 00:02:19,880 Speaker 1: damming streams, and this works by creating a backlog of 35 00:02:19,919 --> 00:02:23,959 Speaker 1: water upstream of the dam. The resulting pond not only 36 00:02:24,000 --> 00:02:26,640 Speaker 1: gives beavers a place to build their lodge, it also 37 00:02:26,680 --> 00:02:31,160 Speaker 1: affords easy access to surrounding trees. Often around a foot 38 00:02:31,240 --> 00:02:33,160 Speaker 1: or a third of a meter, of water covers the 39 00:02:33,240 --> 00:02:36,240 Speaker 1: bases of nearby pines and hardwoods that once stood on 40 00:02:36,320 --> 00:02:39,640 Speaker 1: dry ground. As a result, beavers can swim right up 41 00:02:39,680 --> 00:02:42,920 Speaker 1: to these trees. They also like to dig canals that 42 00:02:42,960 --> 00:02:45,680 Speaker 1: branch out of the new ponds, penetrating deep into the 43 00:02:45,680 --> 00:02:50,959 Speaker 1: local forest. These new wetlands provide homes for smaller animals 44 00:02:51,040 --> 00:02:55,120 Speaker 1: like amphibians. Plus, the dams make great natural filters, a 45 00:02:55,160 --> 00:03:00,320 Speaker 1: blocking excess nitrogen from our creeks and streams. However, all 46 00:03:00,360 --> 00:03:03,560 Speaker 1: of the side effects are positive. When a beaver dam fails, 47 00:03:03,639 --> 00:03:07,320 Speaker 1: it's liable to flood towns or farms. The aftermath can 48 00:03:07,400 --> 00:03:10,840 Speaker 1: be expensive. In the southeastern US alone, these floods are 49 00:03:10,880 --> 00:03:14,200 Speaker 1: responsible for an estimated twenty two million dollars a year 50 00:03:14,280 --> 00:03:18,560 Speaker 1: in damages to the timber industry. It's not surprising, then, 51 00:03:18,600 --> 00:03:21,800 Speaker 1: that many people view beavers as pests. If you have 52 00:03:21,840 --> 00:03:25,080 Speaker 1: a beaver problem, do know that humane solutions are out there. 53 00:03:27,680 --> 00:03:31,840 Speaker 1: Next up the adorable yet terrifying hippopotamus. Put a group 54 00:03:31,840 --> 00:03:34,600 Speaker 1: of hippos and a floodplain with lots of nice, soft soil, 55 00:03:34,680 --> 00:03:39,320 Speaker 1: and they'll start reconfiguring the turf. That's because hippos have 56 00:03:39,480 --> 00:03:41,920 Speaker 1: unique skin that needs to be kept wet for most 57 00:03:41,960 --> 00:03:45,640 Speaker 1: of the day or they'll become dehydrated, so they plow 58 00:03:45,720 --> 00:03:49,000 Speaker 1: through the reed beds that ring rivers and lakes, creating 59 00:03:49,080 --> 00:03:51,920 Speaker 1: deep wallows of water and mud that keep them cool 60 00:03:52,000 --> 00:03:56,280 Speaker 1: during hot days. They're too heavy to float or swim, 61 00:03:56,360 --> 00:03:58,760 Speaker 1: so they reshape the soil bed beneath the water to 62 00:03:58,840 --> 00:04:04,040 Speaker 1: walk along it, the tops of their heads poking out. However, 63 00:04:04,200 --> 00:04:06,840 Speaker 1: these wallows don't offer much in the way of food, 64 00:04:07,120 --> 00:04:10,160 Speaker 1: so at night hippos leave their comfy wallows to go 65 00:04:10,200 --> 00:04:14,760 Speaker 1: grazing on dry land, returning before the sun. That daily 66 00:04:14,880 --> 00:04:18,000 Speaker 1: coming and going creates deep depressions in the soil near 67 00:04:18,040 --> 00:04:23,000 Speaker 1: bodies of water, which in turn become channels worn down 68 00:04:23,000 --> 00:04:26,040 Speaker 1: over time. These footpaths can be as much as sixteen 69 00:04:26,080 --> 00:04:29,520 Speaker 1: feet that's five meters wide, and just like gator holes, 70 00:04:29,560 --> 00:04:33,120 Speaker 1: they're quick to fill up with water. Oh what's more, 71 00:04:33,400 --> 00:04:36,720 Speaker 1: hippo highways linking ponds and streams to big rivers can 72 00:04:36,760 --> 00:04:40,240 Speaker 1: also be established. If the area should flood, these connection 73 00:04:40,360 --> 00:04:43,880 Speaker 1: points may become an outlet for surging water. They also 74 00:04:44,040 --> 00:04:48,080 Speaker 1: enable swamplands to expand and under the right circumstances, The 75 00:04:48,160 --> 00:04:50,919 Speaker 1: trench like trails can divert a great deal of sediment 76 00:04:51,000 --> 00:04:56,040 Speaker 1: from rivers into ponds. And that's not all that hippos 77 00:04:56,040 --> 00:04:59,160 Speaker 1: are doing as they go about their business. Pun intended 78 00:05:00,040 --> 00:05:03,240 Speaker 1: fifteen analysis determined that hippo dung is an important source 79 00:05:03,279 --> 00:05:05,520 Speaker 1: of nutrition for at least some of the fish and 80 00:05:05,560 --> 00:05:09,240 Speaker 1: insects that share the animal's native range. Never underestimate the 81 00:05:09,279 --> 00:05:14,120 Speaker 1: power of poop. However, for their size, hippos don't actually 82 00:05:14,120 --> 00:05:15,960 Speaker 1: eat a lot, only about one to one and a 83 00:05:16,000 --> 00:05:19,240 Speaker 1: half percent of their body weight every day. Large cattle 84 00:05:19,320 --> 00:05:21,919 Speaker 1: eat more like two and a half percent, and African 85 00:05:21,960 --> 00:05:24,960 Speaker 1: elephants can eat over four percent, which is no joke 86 00:05:25,040 --> 00:05:28,200 Speaker 1: when you weigh some seven tons. On a typical day, 87 00:05:28,240 --> 00:05:31,480 Speaker 1: an adult elephant will spend twelve to eighteen hours eating, 88 00:05:31,839 --> 00:05:36,159 Speaker 1: which is vital to the ecosystem. Elephant dung is a 89 00:05:36,200 --> 00:05:39,400 Speaker 1: nutritious fertilizer for the soils of Africa. It's also a 90 00:05:39,480 --> 00:05:43,479 Speaker 1: vehicle by which many seeds are dispersed. Furthermore, by knocking 91 00:05:43,520 --> 00:05:47,840 Speaker 1: down trees and eating shrubs, these colossal animals convert forests 92 00:05:47,880 --> 00:05:53,040 Speaker 1: into grasslands, and a two thousand and nine study published 93 00:05:53,080 --> 00:05:56,640 Speaker 1: in the journal Bioscience revealed even more about the transformative 94 00:05:56,680 --> 00:06:00,360 Speaker 1: powers that African elephants have over their habitats. Sort of 95 00:06:00,400 --> 00:06:04,440 Speaker 1: similar to hippos, Elephants are great at building water channels. 96 00:06:05,200 --> 00:06:08,080 Speaker 1: The test herbivores cover the same land routes over and 97 00:06:08,120 --> 00:06:10,680 Speaker 1: over again as they go about finding food and water, 98 00:06:11,120 --> 00:06:15,760 Speaker 1: making trails in the process. Sometimes multiple generations of elephants 99 00:06:15,760 --> 00:06:19,640 Speaker 1: will reuse the exact same footpaths. As time goes by, 100 00:06:19,960 --> 00:06:23,880 Speaker 1: the animals compress the soil, turning their walkways into trenches, 101 00:06:25,680 --> 00:06:28,679 Speaker 1: and when elephants move back and forth between bodies of water, 102 00:06:29,040 --> 00:06:33,480 Speaker 1: their sunken trails become nice conduits. Thus, rivers or ponds 103 00:06:33,480 --> 00:06:36,839 Speaker 1: that were once isolated can be merged via elephant made canals, 104 00:06:37,040 --> 00:06:41,640 Speaker 1: providing inroads for other wildlife to travel. And another study 105 00:06:41,680 --> 00:06:44,440 Speaker 1: of Asian elephant trails in Thailand found that these paths 106 00:06:44,480 --> 00:06:47,839 Speaker 1: can divert monsoon run off into local streams, preventing flooding. 107 00:06:50,200 --> 00:06:54,280 Speaker 1: But enough of mammals and reptiles. A number of crustaceans 108 00:06:54,320 --> 00:06:58,160 Speaker 1: are great diggers, including fiddler crabs, which shelter in tunnels 109 00:06:58,160 --> 00:07:01,080 Speaker 1: measuring up to three feet or more in that's about 110 00:07:01,080 --> 00:07:04,360 Speaker 1: a meter. The holes are quite a construction project. Given 111 00:07:04,400 --> 00:07:06,800 Speaker 1: the fact that most fiddler species are less than two 112 00:07:06,800 --> 00:07:11,880 Speaker 1: inches or five centimeters wide, then there are the various 113 00:07:11,920 --> 00:07:15,239 Speaker 1: species of burrowing crabs of the mangrove swamps and salt 114 00:07:15,280 --> 00:07:18,800 Speaker 1: marshes of the world. The tunnels that these small crabs 115 00:07:18,840 --> 00:07:22,800 Speaker 1: build are liable to weaken the surrounding turf. On mangrove 116 00:07:22,840 --> 00:07:26,240 Speaker 1: swamp shorelines, this has the effect of widening tidal creeks, 117 00:07:26,360 --> 00:07:29,240 Speaker 1: whose mud and clay based banks are rendered more vulnerable 118 00:07:29,240 --> 00:07:33,360 Speaker 1: to erosion by the digging invertebrates. They may also play 119 00:07:33,400 --> 00:07:36,400 Speaker 1: a key role in aerating the marshy soil and kicking 120 00:07:36,480 --> 00:07:40,560 Speaker 1: up nutrients from the beds, and that's just part of 121 00:07:40,600 --> 00:07:44,080 Speaker 1: the story. Because burrowing crabs have such a profound effect 122 00:07:44,160 --> 00:07:47,800 Speaker 1: on sediment composition, their tunnels can also cause completely new 123 00:07:47,880 --> 00:07:52,160 Speaker 1: creeks to form within these mangrove systems, and all of 124 00:07:52,160 --> 00:07:55,120 Speaker 1: this further impacts the plants and other animals that live 125 00:07:55,160 --> 00:07:59,720 Speaker 1: around those environments. Those tiny crabs change how microorganisms in 126 00:07:59,720 --> 00:08:03,720 Speaker 1: places can grow, which changes what foragers and predators come 127 00:08:03,760 --> 00:08:07,640 Speaker 1: to the area. Just another example of how small actions 128 00:08:07,680 --> 00:08:15,560 Speaker 1: can add up to huge effects. Today's episode is based 129 00:08:15,600 --> 00:08:18,800 Speaker 1: on the article Eco engineers five animals that can reshape 130 00:08:18,800 --> 00:08:22,040 Speaker 1: Earth's waterways on how stuffworks dot Com. Written by Mark Vancini. 131 00:08:22,480 --> 00:08:24,760 Speaker 1: Brain Stuff is production by Heart Radio in partnership with 132 00:08:24,800 --> 00:08:27,160 Speaker 1: how stuffworks dot Com and is produced by Tyler Klang. 133 00:08:27,800 --> 00:08:30,880 Speaker 1: Four more podcasts from my heart Radio. Visit the iHeartRadio app, 134 00:08:30,960 --> 00:08:35,080 Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows.