Ants Have Big Impact on Environment as Ecosystem Engineers
Firstly, through moving of soil by nest building2 activity and by collecting food they affect the level of nutrients in the soil. This can indirectly impact the local populations of many animal groups, from decomposers to species much higher up the food chain.
Dirk Sanders, an author of the study from the universitys Centre for Ecology and Conservation, said:Ants are very effective predators which thrive in huge numbers. Theyre also very territorial3 and very aggressive, defending their resources and territory against other predators. All of this means they have a strong influence on their surrounding area.
The study, carried out in Germany, studied the impact of the presence of different combinations and densities of black garden ants and common red ants, both species which can be found across Europe, including in the UK. It found that a low density of ants in an area increased the diversity and density of other animals in the local area, particularly the density of herbivores and decomposers. At higher densities ants had no or the opposite effect, showing that predation is counteracting the positive influence.
Ants are important components of ecosystems not only because they constitute a great part of the animal biomass5 but also because they act as ecosystem engineers. Ant biodiversity6 is incredibly high and these organisms are highly responsive to human impact, which obviously reduces its richness. However, it is not clear how such disturbance damages the maintenance of ant services to the ecosystem. Ants are important in below ground processes8 through the alteration of the physical and chemical environment and through their effects on plants, microorganisms, and other soil organisms.
predator n.食肉动物
decomposer n.腐生物;分解体
subtlety n ，微妙，精妙
注释：
2. nest building ：筑巢
4. an increase in density and diversity of other animal groups ：其他动物群体在数量和品种上的增长。
6. biodiversity ：物质名词，由bio和diversity 两部分组成，意为生物多样性。
8. below ground processes ：土壤下面的过程，即影响生态环境的过程。
1 .Why are ants compared to ecosystem engineers?
B Because they collect food.
D Because they are predators.
A prey on small as well as large animals.
C collect food as decomposers.
3. Dir Sanders study centered on how ants
B defend their resources and territory against other predators.
D produce such a big impact on the environment.
A Ants bring about a negative influence to an area when their population is small.
C Ants predation counteracts the positive influence they may have on an area.
5. What still remains unclear about ants, according to the last paragraph?
B How do ants affect the animal diversity in a given ecosystem?
D How do ants alter the physical and chemical environment?
1. C 短文的第一段提供了答案。A不是正确答案，因为并不是因为蚂蚁会筑巢才被誉为生态系统工程师，而是因为它们筑巢和获取食物的方式改变了土壤的营养水平，为整个食物链提供了很好的生态环境。
3.D Dirk Sanders说：In this research, we studied for the first time how big this impact is and the subtleties of it.所以，D是正确选择。句中the subtleties of it 的意思是：蚂蚁对环境影响的精妙之处。
5.C 最后一段的第二和第三句提供了答案。第二句告诉我们，蚂蚁极易受人类的影响，第三句告诉我们，科学家还不清楚人类对蚂蚁这种干扰如何破坏蚂蚁对生态系统的维护作用。