Ants Have Big Impacton Environment as " Ecosystem Engineers"

Research by the University of Exeter has revealed that ants have a bigimpact on their local environment

as a result of theiractivity as"ecosystem engineers"and predators.The study,published inthe Journal of

Animal Ecology,foundthat ants have two distinct effects on their local environment?

Firstly.throuahmoving the soil by nest building activity and by collecting food they affectthe level of

nutrients in thesoil.This can indirectly impact the local populations of many animalgroups,from decomposers

to species muchhigher up the food chain.

Secondly,they preyon a wide range of other animals,including larger prey which can be attacked by

vast numbers of antworkers.

Dirk Sanders,anauthor of the study from the university's Centre for Ecology andConservation,said,

"Ants are veryeffective predators which thrive in huge numbers.They're also very territorialand very ag-

gressive,defendingtheir resources and territory against other predators.All of this means theyhave 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 thatdespite being predators,their presence can also lead to an increase in densityand diversity of

other animalgroups.They genuinely play a key role in the local environment,having a biginfluence on the

grassland foodweb,"Sanders said.

The study,carriedout in Germany,studiedthe impact of the presence of different combinations and den-

sities of blackgarden ants and common red ants,both of which can be found across Europe,including the

UK. It found that a low density of ants in anarea increased the diversity and density of other animals in the

localarea,particularly the density of herbivores and decomposers.At higher densitiesants had no or the op-

posite effect,thepredation 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 hasa positive effect on animal groups at low levels,but as the number of antsincreases,their

predatory impactshave the bigger effect一therebycounteracting the positive influence via ecosystem

engineering.

Ants are importantcomponents of the ecosystem not only because they constitute a great part ofthe ani--

mal biomass but alsobecause they act as ecosystem engineers.Ant biodiversity is incredibly high andthese

organisms are highlyresponsive to human impact,which obviously reduces its richness.However,it isnot

clear how suchdisturbance damages the maintenance of ant services to the ecosystem.Ants areimportant in

below groundprocesses through the alteration of the physical and chemical environment andthrough their

effects onplants,microorganisms,and other soil organisms.What stillremains unclear about ants,according to the last paragraph?

A.What roles antsplay in the ecosystem in which they live.

B.How ants affectthe animal diversity in a given ecosystem.

C.How humanactivities affect ants'influence on a given ecosystem.

D.How ants alter thephysical and chemical environment.