Date on Master's Thesis/Doctoral Dissertation

5-2018

Document Type

Doctoral Dissertation

Degree Name

Ph. D.

Department

Biology

Degree Program

Biology, PhD

Committee Chair

Yanoviak, Stephen

Committee Co-Chair (if applicable)

Dugatkin, Lee

Committee Member

Dugatkin, Lee

Committee Member

Eason, Perri

Committee Member

Emery, Sarah

Committee Member

Schnitzer, Stefan

Author's Keywords

arboreal; epigeic; formicidae; Panama; Liana; community

Abstract

This dissertation explores the role that physical connections among and within habitats play in determining the local diversity and behaviors of cursorial organisms. Understanding the processes that regulate local community assembly and that contribute to the maintenance of species diversity is a cornerstone of community ecology. Ants are a useful model for studies of local communities because they are abundant and fulfill a variety of ecological roles. Chapter one of the dissertation examines the how lianas (woody vines) function as connective structures among tree crowns and how these connections affect arboreal ant community structure within a tropical forest canopy. Trees without lianas act as islands and the number of ant species living in these isolated trees can be predicted by tree size alone. Chapter two describes an experimental approach to examining the relationship between arboreal ants and lianas. Cutting lianas out of trees and connecting trees with ropes revealed that connectivity is a key resource that lianas provide to arboreal ants. The removal of lianas decreased species richness and caused the development of a strong, positive species-area relationship between ant species richness and tree size. Connecting neighboring trees together with ropes completely mitigated the effects of liana removal. Chapter three explored how ants use physical pathways to move across the forest floor. Ants will readily use exposed roots or ropes as highways to move through the complex matrix of leaf litter on the forest floor. As a result, ants appeared in higher frequency on these structures compared to the nearby leaf litter. Increasing the number of paths in an area also increased the rate of discovery and recruitment to food resources by focal species. In combination, these observations and experimental manipulations highlight how connecting isolated habitats or providing bridges through complex environments can enhance local species diversity and promote a variety of interactions among organisms at small spatial scales.

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