Grazing by large savanna herbivores indirectly alters ant diversity and promotes resource monopolisation

PeerJ

article

Jean Purdon¹  Catherine L. Parr²  Michael J. Somers¹ 

[1] Eugène Marais Chair of Wildlife Management, Centre for Invasion Biology, Mammal Research Institute, University of Pretoria;School of Environmental Sciences, University of Liverpool;Environmental Change Institute, School of Geography and the Environment, University of Oxford

关键词: Ants;    Grazing lawns;    Bunch grass;    Resource monopolisation;    Competitive interactions;    Assemblages;    Body size;    Herbivory;   

DOI  :  10.7717/peerj.6226

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

In savannas, grazing is an important disturbance that modifies the grass layer structure and composition. Habitat structural complexity influences species diversity and assemblage functioning. By using a combination of natural sites and manipulated experiments, we explored how habitat structure (grazing lawns and adjacent bunch grass) affects ant diversity and foraging behaviour, specifically the efficiency of resource acquisition, resource monopolisation and ant body size. We found that in the natural sites there was no difference in the amount of time ants took to locate resources, but in the manipulated experiments, ants were faster at locating resources and were more abundant in the simple treatments than in the more complex treatments. Ant body size was only affected by the manipulated experiments, with smaller ants found in the more complex treatments. In both the grazing lawn and bunch grass habitats there were differences in assemblage patterns of ants discovering resources and those dominating them. Seasonality, which was predicted to affect the speed at which ants discovered resources and the intensity of resource monopolisation, also played a role. We show that ants in winter monopolised more baits and discovered resources at a slower rate, but only at certain times within the experiment. Grazing in conjunction with season thus had a significant effect on ant diversity and foraging behaviour, with dominant ants promoted where habitat complexity was simplified when temperatures were low. Our results indicate that structural complexity plays a major role in determining ant assemblage structure and function in African savannas.

【 授权许可】

CC BY