Research by the University of Exeter has revealed that ants have a bigimpact on their local en-vironment as a result of their activityas"ecosystem engineers"and

predators.Thestudy,published in the Journal of Animal Ecology,found that ants have twodistinct effects on their local environment.

Firstly,throughmoving of soil by nest building activity and by collecting food they affect thelevel of nutrients in the soil.This can indirectly impact the local populationsof

many animal groups,from decomposers to species much higher up the food chain.

Secondly,they preyon a wide range of other animals,including larger prey which can be at-tackedby vast numbers of ant workers.

Dirk Sanders,anauthor of the study from the university's Centre for Ecology and Conservation,saiD."Ants are very effective predators which thrive in hugenumbers.They're

also veryterritorial and very aggressive,defending their resources and territory againstother predators.All of this means they have a strong influence on theirsurrounding

area."

"In thisresearch,we studied for the first time how big this impact is and thesubtleties of it. What we found is that despite being predators,their presencecan also lead to an

increase in densityand diversity of other animal groups.They genuinely play a key role in thelocal environment,haying a big influence on the grassland foodweb,"Sanders

said.

The study,carriedout in Germany,studiedthe impact of the presence of different combinations and densities of blackgarden ants and common red ants,both species which

can be found acrossEurone.including in the UK.It found that a low density of ants in an area increasedthe diversity and density of other animals in the local area,particularly

the density ofherbivores and decomposers.At higher densities ants had no or the oppositeeffect,showing that predation is counteracting the positive influence.

Dr Frank vanVeen,another author on the study,saiD."What we find is that the impact ofants on soil nutrient levels has a positive effect on animal groups at lowlevels,but as

the number of antsincreases,their predatory impacts have the bigger effect一thereby counteracting the positiveinfluence via ecosystem engineering."

Ants are importantcomponents of ecosystems not only because they constitute a great part of theanimal biomass but also because they act as ecosystem engineers.Ant

biodiversity isincredibly high and these organisms are highly responsive to human impact,whichobviously reduces its richness. However,it is not clear how such disturbance

damages themaintenance of ant services to the ecosystem.Ants are important in below groundprocesses through the alteration of the physical and chemical environment and

through theireffects on plants,microorganisms,and other soil organisms.

Dir Sanders' studycentered on how ants_________.

A.can manage tothrive in huge numbers

B.defend theirresources and territory against other predators

C.attack thoseinvading animals for survival

D.produce such a bigimpact on the environment