From: Sustainable Man
Encyclopaedia Britannica (definition) Wikiwand (illustration) Trophic cascade is an ecological phenomenon triggered by the addition or removal of top predators and involving reciprocal changes in the relative populations of predator and prey through a food chain, which often results in dramatic changes in ecosystem structure and nutrient cycling. American zoologist Robert Paine coined the term trophic cascade in 1980 to describe reciprocal changes in food webs caused by experimental manipulations of top predators. In many instances, trophic cascades have been initiated by human persecution and harvesting of top carnivores such as: wolves and big cats in terrestrial ecosystems and sharks, tunas, and game fish in aquatic ecosystems. The most notable example of how fundamentally significant a trophic cascade can be is the reintroduction of grey wolves to Yellowstone National Park. In Yellowstone, the grey wolf was locally extinct by 1920 and reintroduced in 1995 and 1996. The dramatic changes brought about by their reintroduction are best described in an excellent short documentary featured on Sustainable Man site. For our language learning purposes, I am reposting both the transcript and the documentary here: (Voiceover. Narrated by George Monbiot) “One of the most exciting scientific findings of the past half century has been the discovery of widespread trophic cascades. A trophic cascade is an ecological process which starts at the top of the food chain and tumbles all the way down to the bottom. And the classic example is what happened in the Yellowstone National Park in the United States when wolves were reintroduced in 1995. Now, we – we all know that wolves kill various species of animals, but perhaps we’re slightly less aware that they give life to many others. Before the wolves turned up – they’d been absent for 70 years – the numbers of deer (because there had been nothing to hunt them) had built up and built up in the Yellowstone Park and despite efforts by humans to control them they’d managed to reduce much the vegetation there to almost nothing. They had just grazed it away. But as soon as the wolves arrived, even though they were few in number, they started to have the most remarkable effects. First, of course, they killed some of the deer but that wasn’t the major thing. Much more significantly, they radically changed the behaviour of the deer. The deer started avoiding certain parts of the park – the places where they could be trapped most easily – particularly the valleys and the gorges and immediately those places started to regenerate. In some areas, the height of the trees quintupled in just six years. Bare valley sides quickly became forests of aspen and willow and cottonwood. And as soon as that happened, the birds started moving in. The number of songbirds and migratory birds started to increase greatly. The number of beavers started to increase because beavers like to eat the trees. And beavers, like wolves, are ecosystem engineers. They create niches for other species. And the dams they built in the rivers provided habitats for otters and muskrats and ducks and fish and reptiles and amphibians. The wolves killed coyotes and as a result of that, the number rabbits and mice began to rise which meant more hawks more weasels more foxes more badgers. Ravens and bald eagles came down to feed on the carrion that the wolves had left. Bears fed on it, too. And their population began to rise as well partly also because there were more berries growing on the regenerating shrubs. And the bears reinforced the impact of the wolves by killing some of the calves of the deer. But here’s where it gets really interesting. The wolves changed the behaviour of the rivers. They began to meander less. There was less erosion. Their channels narrowed. More pools formed. More riffle sections. All of which were great for wildlife habitats. The rivers changed in response to the wolves. And the reason was that the regenerating forests stabilised the banks so that they collapsed less often. So the rivers became more fixed in their course. Similarly, by driving the deer out of some places, and the vegetation recovering on the valley side, there was less soil erosion because the vegetation stabilised that as well. So the wolves, small in number, transformed not just the ecosystem of the Yellowstone National Park – this huge area of land… but also, its physical geography. |
MORGAN MOTORS GLOSSARY the world over = all over the world craftsmanship = the skill someone uses to make beautiful things with their hands, zanatsko umeće to establish = to found, to create a three-wheeler = a bike or a car that has three wheels, trotočkaš a 4-4 = a " four-by-four", a system in which a car's engine powers all 4 wheels evenly, vozilo sa pogonom na sva četiri točka iconic = important or impressive because it seems to be a symbol of sth core = central, key, essential ash = a kind of a widespread deciduous tree, jasen bespoke = specially made for the customer who orders it, pravljen po narudžbi tailored = fitted, made or produced to fit closely to one's measures, skrojen heritage = qualities, traditions and features that have continued over many years and have been passed on from one generation to another, legacy cutting-edge (adj.) = the latest, most modern, innovative a roadster = a sports car with no roof and only two seats a two-seater = dvosed in excess of = more than to assemble = to put parts together to make the whole approximately = not precisely, not exactly, roughly multiple = more than one significant stake = major part venture capitalist = an investor who provides capital to companies with a high growth potential eponymous = in the title role to facilitate = to make sth easier or more likely to happen Lord Lucan Crime Mystery Glossaryto shroud = surround a situation or an object making it mysterious and secret
subsequent = that comes after or later Earl = grof to grab (the) headlines = get a lot of publicity from media bloodstained = covered with stains of blood a stain = a mark on sth that is difficult to remove, mrlja to burst (into a place) = to enter suddenly with a lot of energy or force Countess = grofica an assault = an attack substantial = big, considerable ground floor = the floor of a building that is level or almost level with the ground outside basement = the floor of a building which is partly or completely below ground level premises = all the buildings and land that something occupies in one place unharmed = not injured or hurt to fetch = go and get to splash = (of a liquid) to hit something and scatter in a lot of small drops to be battered = to be heavily beaten blunt = not sharp lead = soft, grey, heavy metal, olovo, olovni piping = same as pipe, cev to bend/bent, bent = saviti to doze (off) = to sleep lightly usu during the day, to nap, dremati insistently = to keep insisting incoherent = to be talking in a confusing and unclear way a ward of court = pod sudskim starateljstvom to reside = to live or stay somewhere the battery is/was flat = akumulator je (bio) ispražnjen to admit = to allow someone to come in dishevelled = very untidy, unkempt flannels = men's trousers (made of flannel) to sponge (off) = to wipe with a sponge to peep = to have a quick look at something, often secretly ad quietly a smear = a dirty or oily mark to persuade = to talk sbd into doing sth, nagovarati to validate = to confirm or prove that sth is true or correct to abandon = to desert, leave a place bandaged = wrapped, uvijen, umotan CROSSWORD |