Title

Terrestrial-aquatic connections : riparian invasion by Lonicera maackii drives shifts in aquatic biota and ecosystem processes

Date of Award

2016

Degree Name

Ph.D. in Biology

Department

Department of Biology

Advisor/Chair

Advisor: Ryan W. McEwan

Abstract

Invasive species are of global importance due to their impacts on ecological communities, habitat structure, native community dynamics, and ecosystem processes. Scientists and conservation managers are increasingly focusing on the biological impacts of invasive species and devising management practices that emphasize the health of ecosystems based on measured biological processes. Lonicera maackii is a highly successful invasive shrub in forests of eastern and Midwestern North America. We investigated how riparian invasion of L. maackii influenced (1) the availability of in-stream leaf litter resources, algal growth, above stream canopy cover, and light available to the stream, (2) the functional and taxonomic diversity and community composition of aquatic macroinvertebrate communities, (3) the effects of L. maackii on throughfall chemistry. In summary, the removal of an invasive riparian shrub influenced the timing, deposition, quality, and abundance of leaf litter habitat into a headwater stream, ostensibly driving bottom-up effects on aquatic primary producer biomass and the macroinvertebrate community. Patterns in macroinvertebrate community and functional trait dynamics were influenced by seasons and the L. maackii riparian forest. These findings suggest that functional traits were driven by life history strategies linked with seasonal patterns in temperature and food resources that are also influenced by L. maackii riparian forests. In addition, riparian L. maackii has the potential to alter nutrient subsidies during rain events that enter aquatic systems as throughfall, and suppress stream algal growth early in the growth season, impacting nutrient cross-system subsidies and one of the basal food resources in aquatic systems. Based on these findings we have developed a predictive framework for understanding how this terrestrial invasive shrub influences aquatic ecosystems.

Keywords

Invasive plants Environmental aspects Middle West, Freshwater invertebrates Effect of habitat modification on, Honeysuckles Middle West, Rivers Ecology Middle West, Biology, Ecology, Invasive species, Stream, Lonicera maackii, Macroinvertebrate, Functional Diversity, Nutrient Dynamics, Riparian

Rights Statement

Copyright 2016, author

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