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环境历史包裹在河马的牙齿表明偷猎是改变非洲# 8217年代景观

发布时间:2018-09-26 编辑:admin

Credit: Pixabay

Credit: Pixabay

Megaherbivores such as elephants and hippos like to graze on lowland tropical grasses, but they also browse the twigs, shoots, leaves, and fruits of bushes and trees。 There’;s more to this diet than meets the eye, though。

These animals, particularly the elephants which have a big appetite, help keep woody plant encroachment in check。 But now that many of these megaherbivores have been killed, either by poaching or habitat loss, the vegetation of Africa’;s savannas is changing —; and it all strikingly shows in hippo teeth, a new study found。

Ask and nature will provide

There is not one, but three forms of photosynthesis —; the essential biological process that harnesses energy from sunlight into chemical energy。 These types are known as C3, C4 and CAM。

Tropical grasses, such as those commonly found in an elephant’;s ecosystem, are C4 plants because of these employ a unique enzyme to process CO2 into sugars during photosynthesis。 Other C4 plants include corn and sugarcane。 Also, in the elephant’;s surroundings are C3 plants, which use a different enzyme, like trees, shrubs, herbs and various flowering plants。

The two classes of plants, C3 and C4, are in direct competition for resources, sunlight no exception, and megaherbivores like elephants act like nature’;s gardeners, keeping everything in balance。 Since the 1960s, however, elephant populations have plummeted which has led to a significant advance of C3 plants。 Grasslands, which many animals depend on for food and shelter, have been retreating, on the other hand。

Aerial photographs and ground surveys have confirmed that C3 plants are beginning to take over in the parts of Africa, but these have never been very reliable because you need a lot of data recorded at fixed time intervals to glimpse the big picture。 Many African parks, like  Uganda’;s Queen Elizabeth National Park, have little to any such observations recorded。

本文源自: 环亚娱乐

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