理工A-2+第四十六篇Ants Have Big Impact on Environment as Ecosystem Engineers 蚂蚁作为“生态系统工程师”对环境影响巨大Research by the University of Exeter1 has revealed透露 that ants 蚂蚁have a big impact影响 on their local当地的 environment环境 as a result of their activity活动 as ecosystem engineers and predators捕食者. The study, published in the Journal of Animal Ecology, found that ants have two distinct effects on their local environment.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.Secondly, they prey on a wide range of other animals, including larger prey which can be attacked by vast numbers of ant workers.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.In this research, we studied for the first time how big this impact is and the subtleties of it. What we found is that despite being predators, their presence can also lead to an increase in density and diversity of other animal groups4. They genuinely play a key role in the local environment, having a big influence on the grassland food web, Sanders said.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.Dr Frank van Veen, another author on the study, said:What we find is that the impact of ants on soil nutrient levels has a positive effect on animal groups at low levels, but as the number of ants increases, their predatory impacts have the bigger effect thereby counteracting the positive influence via ecosystem engineering.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.词汇：predator / predt/ n食肉动物nutrient/ nju:trint/ n 营养物；adj营养的decomposer/,di:kmpuz/ n腐生物；分解体prey/prei/ v捕食；n被捕食的动物subtlety/ stlti/ n ，微妙，精妙herbivore/ h:biv: / n 食草动物注释：1.the University of Exeter ：埃克斯特大学。1851 年建校，位于英国西南部重要商业中心埃克斯特市，是英国著名的传统大学之一。2. nest building ：筑巢3. territorial ：领地的。在此用来形容蚂蚁的本性，即具有很强的领地意识，并且会竭尽全力保卫自己的领地。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。5. biomass ：物质名词，由bio和mass 两部分组成，意为“生物量”“生物质”。6. biodiversity ：物质名词，由bio和diversity 两部分组成，意为“生物多样性”。7.the maintenance of ant services to the ecosystem ：蚂蚁对生态系统的维护作用。8. below ground processes ：土壤下面的（工作）过程，即影响生态环境的过程。练习：1 .Why are ants compared to ecosystem engineers?A Because they build their own nests.B Because they collect food.C Because their activity affects the environment.D Because they are predators.2. As predators, antsA prey on small as well as large animals.B collect nutritious food from the soilC collect food as decomposers.D prey on species much higher up the food chain.3. Dirk Sanders study centered on how antsA can manage to thrive in huge numbers.B defend their resources and territory against other predators.C attack those invading animals for survival.D produce such a big impact on the environment.4. What does paragraph 6 tell us?A Ants bring about a negative influence to an area when their population is small.B Ants bring about a positive influence to an area when their population is small.C Ants predation counteracts the positive influence they may have on an area.D At higher density, ants produce a positive influence on an area.5. What still remains unclear about ants, according to the last paragraph?A What roles do ants play in the ecosystem in which they live?B How do ants affect the animal diversity in a given ecosystem?C How do human activities affect ants influence on a given ecosystem?D How do ants alter the physical and c