Reading: Matching Information to Paragraphs: Question 2

A Once found across nearly the whole of the Northern Hemisphere, beavers were hunted to the brink of extinction over several centuries for their thick waterproof fur and for castoreum, a scented secretion once prized in perfumery and medicine. By the early twentieth century the animal had vanished from most of its historic range, and the wetlands it had helped to create slowly dried out or were drained for farmland.

B Where beavers have since been reintroduced, their felled branches and packed mud dams slow the flow of streams, spreading water sideways across a valley floor rather than letting it rush straight down a single channel. Over a few seasons a single family can transform a narrow, fast-flowing stream into a patchwork of shallow pools and boggy ground, gradually raising the level of the water table in the surrounding soil.

C In one fenced trial catchment, hydrologists recorded that water released from a series of thirteen beaver dams during a heavy autumn storm reached the village downstream more than two hours later, and at a peak flow roughly thirty percent lower, than measurements taken in the same catchment before the dams were built.

D As water backs up behind each dam, sediment carried from fields upstream settles out in the resulting pond rather than continuing downstream, and nitrogen and phosphorus from agricultural runoff are broken down by the microbial activity thriving in the still, oxygen-rich margins, so that water leaving a beaver-modified stretch of river is often measurably clearer than water entering it.

E Surveys of these newly flooded margins have repeatedly found sharp increases in the number of dragonfly and damselfly species present, along with a rise in amphibian breeding activity, since the shallow, sun-warmed pools created behind a dam offer exactly the still, vegetated water that these species need to lay eggs.

F Not every neighbour welcomes the change. Farmers whose low-lying fields border a reintroduction site have reported dams backing water up over drainage ditches and access tracks, occasionally flooding land actively in use, and several reintroduction schemes now include a compensation fund or a licensed system for lowering a problem dam without removing the animals themselves.

G Because of this potential for conflict, most countries permit reintroduction only under a formal licence that specifies where animals may be released and how their numbers will be monitored, with some governments still classifying the species as one that may only be kept within a fenced enclosure rather than released into open rivers.

Which paragraph contains the following information?

Write the correct letter, A–G, for each statement.

NB You may use any letter more than once.

1. A specific figure showing how much a set of dams reduced the highest water level reached downstream during a storm.
2. An explanation of why the animal became rare across most of the area it once inhabited.
3. An example of a particular group of insects increasing in number as a result of new wetland habitat.
4. A description of the rules that govern where and how the animals may legally be released.
5. Reference to a practical problem that landowners near a reintroduction site may experience.
6. An explanation of how the ponds created by these animals can remove harmful substances before they reach a river further downstream.
7. A general description of how the animals alter the physical shape and flow pattern of a stream over time.