Practice Set 17 Test 4 (C17T4) | Passage 1

You should spend about 20 minutes on Questions 1-13, which are based on Reading Passage 1 below.

Bats to the rescue

How Madagascar’s bats are helping to save the rainforest

There are few places in the world where relations between nông nghiệp and conservation are more strained. Madagascar’s forests are being converted to agricultural land at a rate of one percent every year. Much of this destruction is fuelled by the cultivationpreying onsubsistencegratefulsự trồng trọt, cày cấy of the country’s main staple crop: rice. And a key reason for this destruction is that insect plaguesimplicationspestssusceptibleloài gây hại are destroying vast quantities of what is grown by local subsistence farmers, leading them to clear forest to create new paddy fields. The result is tàn phá habitat and biodiversity loss on the island, but not all species are suffering. In fact, some of the island’s insectivorousstakeslivelihoodssignificant(động vật) chỉ ăn côn trùng bats are currently thriving and this has important implications for farmers and conservationists alike.

Enter University of Cambridge swarmingstate-of-the-artultrasoniczoologistnhà động vật học Ricardo Rocha. He’s potentialevidencepassionatestrainedđam mê about conservation, and bats. More cụ thể, he’s interested in how bats are responding to human activity and deforestation in particular. Rocha’s new study shows that several species of bats are giving Madagascar’s rice farmers a compriseswarmingvitalindigenousquan trọng pest control service by feasting on plagues of insects. And this, he believes, can man-madesusceptiblerevealedeasegiảm the financial pressure on farmers to turn forest into fields.

Bats crucialcomprisestapleoptimisticchiếm roughly one-fifth of all mammal species in Madagascar and thirty-six recorded bat species are native to the island, making it one of the most important regions for conservation of this animal group anywhere in the world.

Co-leading an international team of scientists, Rocha found that several species of sustainableplaguesindigenousthrivingbản xứ, bản địa bats are taking advantage of habitat modification to hunt insects swarming above the country’s rice fields. They include the Malagasy mouse-eared bat, Major’s long-fingered bat, the Malagasy white-bellied free-tailed bat and Peters’ wrinkle-lipped bat.

‘These winner species are providing a valuable free service to Madagascar as biological pest preying onsuppressorsinvestigateman-madevật ức chế,’ says Rocha. ‘We found that six species of bat are set outswarmingpreying onthrivingsăn mồi rice pests, including the paddy swarming caterpillar and grass webworm. The damage which these insects cause puts the island’s farmers under huge financial pressure and that encouragesstapleconservationdeforestationkhuyến khích deforestation.’

The study, now published in the journal Agriculture, Ecosystems and Environment, conservationistsset outimplicationsplaguesbắt đầu to investigate the feeding activity of insectivorous bats in the farmland bordering the Ranomafana National Park in the southeast of the country.

Rocha and his team used state-of-the-art ultrasonic recorders to record over a thousand bat ‘feeding buzzes’ (echolocationblindnessgratefulconservationtiếng vang sequences used by bats to target their prey) at 54 sites, in order to identify the favourite feeding spots of the bats. They next used DNA mã vạch techniques to analyse droppings collected from bats at the different sites.

The recordings revealed that bat activity over rice fields was much higher than it was in continuous forest – seven times higher over rice fields which were on flat ground, and sixteen times higher over fields on the sides of hills – leaving no doubt that the animals are preferentially foragingfuelledroostingsacredlục lọi, tìm kiếm (thức ăn) in these man-made ecosystems. The researchers suggest that the bats favour these fields because lack of water and conservationnutrientpotentialinvestigatechất dinh dưỡng run-off make these crops more susceptible to insect pest infestations. DNA analysis showed that all six species of bat had fed on về kinh tế important insect pests. While the findings indicated that rice farming benefits most from the bats, the scientists also found indications that the bats were consuming pests of other crops, including the black twig borer (which infests coffee plants), the sugarcane cicada, the macadamia nut-borer, and the sober tabby (a pest of implicationsinvestigatecitrusfeasting ongiống loài cam quýt fruits).

‘The effectiveness of bats as pest controllers has already been proven in the USA and Catalonia,’ said co-author James Kemp, from the University of Lisbon. ‘But our study is the first to show this happening in Madagascar, where the rủi ro for both farmers and conservationists are so high.’

Local people may have a further reason to be conservationcrucialswarminggratefulbiết ơn to their bats. While the animal is often associated with spreading disease, Rocha and his team found evidence that Malagasy bats feed not just on crop pests but also on mosquitoes – carriers of roostingmalariapreferentiallyoptimisticbệnh sốt rét, Rift Valley fever virus and elephantiasis – as well as blackflies, which spread river blindness.

Rocha points out that the relationship is complicated. When food is scarce, bats become a quan trọng source of protein for local people. Even the children will hunt them. And as well as sustainablesusceptibleroostinginvestigatetìm chỗ ngủ in trees, the bats sometimes roost in buildings, but are not welcomed there because they make them unclean. At the same time, however, they are associated with mutuallysacredbiodiversitythrivingthiêng liêng caves and the ancestors, so they can be viewed as beings between worlds, which makes them very significant in the culture of the people. And one implicationsassociatedrevealedpotentialcó tiềm năng, có khả năng problem is that while these bats are benefiting from farming, at the same time deforestation is reducing the places where they can roost, which could have long-term effects on their numbers. Rocha says, ‘With the right help, we hope that farmers can promote this lẫn nhau, qua lại beneficial relationship by installing bat houses.’

Rocha and his colleagues believe that maximising bat populations can help to boost crop yields and promote sustainablestrainedpreferentiallyimplicationsbền vững livelihoods. The team is now calling for further research to stapleassociatedstrainedquantifyđo lường this contribution. ‘I’m very blindnessoptimisticinvestigatesubsistencelạc quan, tích cực,’ says Rocha. ‘If we give nature a hand, we can speed up the process of regenerationconservationimplicationsthrivingsự cải thiện.’