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CELPIP Practice Reading: Reading for Information ID: #63109 Medium Tundra lichens: slow growth and caribou forage

Read the following passage.

A. On rock outcrops in the boreal forest and across the Arctic tundra, the ground is often covered with pale, branching reindeer lichens. One of them, the star-tipped reindeer lichen, grows in every province and territory and forms rounded mounds that look like little heads of cauliflower; on dry days it crunches underfoot. In an online vote held by the Canadian Museum of Nature, it was Canadians' top choice for a national lichen. Although it looks like a plant, a lichen is a partnership between a fungus and green algae or cyanobacteria, and perhaps 2,500 kinds are found in Canada.

B. Reindeer lichens grow upward at the tip while the base slowly dies, forming dense mats about 4 to 12 centimetres tall. Their growth is slow: average rates of 4.8 to 11.1 millimetres a year have been reported, along with average ages of more than 100 years. Because they can absorb water directly from the air, they can take over soils that are too dry, and often too cold, for plants with roots. When a caribou steps on a mound, small spiky pieces break off, catch in its hair and are carried to a new place.

C. Barren-ground caribou depend on lichens for most of their winter diet, and caribou are one of the few mammals able to feed on and digest them. Caribou find lichens under the snow by their excellent sense of smell and dig them out with their broad hooves. In caribou sampled from October to April in the Northwest Territories, northern Saskatchewan and northern Manitoba, these lichens formed 40.5 to 62.5 per cent of stomach contents by dry weight. Lichens supply energy but little protein, so in spring caribou switch to fresh green plants.

D. Fire and heavy grazing both strip away lichen cover, and its return is still being studied. In jack pine woodlands of northern Saskatchewan and northeastern Alberta, reindeer lichens began to reestablish within 1 to 3 years after fire, and in one Northwest Territories study they dominated the ground in forests burned 20 to 60 years earlier. Heavy trampling by large numbers of caribou can set recovery back by many decades. A researcher who studied caribou in Nunavut suggested that fire severity and grazing intensity may matter more than time since the fire. It is also often hard to tell whether lichens on a burned site grew from pieces blown in from elsewhere or from small pieces that survived.

E. Not given in any of the above paragraphs.

Decide which paragraph, A to D, has the information given in each statement below. Select E if the information is not given in any of the paragraphs.

 - 1. Researchers have found that these lichens can live, on average, for more than a century.

 - 2. A lichen is formed by two different kinds of living things joined together.

 - 3. The winner of the museum's online contest is the most plentiful lichen in the country.

 - 4. Caribou rely on scent to locate food hidden beneath the snow.

 - 5. In some places, the lichens start to come back just a few years after flames pass through.

 - 6. Because they take in moisture straight from the atmosphere, they can grow on ground too dry for rooted plants.

 - 7. When many caribou walk over the lichen, it can take decades longer to recover.

 - 8. An adult caribou eats several kilograms of lichen on a typical winter day.

 - 9. Scientists are unsure whether new growth after a fire comes from outside or from bits that lived through it.

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