The community structure of ants and their response to land use changes in Madagascar

• Main Author: Finch, Elizabeth Anne
• Published: Queen's University Belfast 2017
• Subjects: 595.79
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.726341

Slash and burn agriculture is the dominant form of agriculture in the tropics. However, increasing population growth has led to the intensification of this form of agriculture. The potential impacts of this on faunal diversity, however, have never been studied. This thesis aimed to fully understand how slash and burn agriculture affects ant communities and the underlying processes determining their assembly in Madagascar. This research shows that at the regional scale, geographical distance was the most important factor influencing ant communities in habitats associated with slash and burn agriculture. Additionally, environmental filtering was also shown to affect community composition, as across sites there was a significant correlation between morphological traits and environmental variables. Slash and burn agriculture was also shown to lead to declines in the ant species richness and increases in abundance and richness of introduced ant species. Correlations between the richness and abundance of introduced species and native species in this thesis, however, suggest that this was not causative. Additionally, slash and burn agriculture also led to a reduction in function diversity, functional evenness, as well as reduced ranges of body size, leg length and mandible size. This suggests that the diverse range of functional roles provided by ants was also affected by this form of agriculture. Finally, this thesis examines the benefits of natural regeneration and active reforestation for ant communities. Results show that natural regeneration was more effective at restoring functional diversity, whereas natural regeneration was more effective at restoring species diversity back to levels found in closed canopy forest. Neither, however were capable of restoring the community composition found in closed canopy forest. Given the need for restoring and conserving functional ecosystems, this thesis suggests that active reforestation should be adopted in areas of most importance, i.e. areas which could increase connectivity between remnant forest patches.