Date of Award:

5-2022

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Watershed Sciences

Committee Chair(s)

Timothy Walsworth

Committee

Timothy Walsworth

Committee

Edward Hammill

Committee

Peter Adler

Abstract

Environmental damage associated with a growing human population will increase globally without active management. Restoration can promote ecosystem recovery, yet often fails to produce desired results and may require decades to achieve noticeable benefits. Detecting small, incremental change sis imperative in these difficult situations. Here, I demonstrate that restoration focused on fish removal triggers incremental responses in aquatic plants and animals. Removing common carp is expected to encourage recovery of aquatic plants, increasing animal habitat, resulting in more macroinvertebrates (e.g., aquatic insects, snails). Carp removal should also increase water clarity, improving visibility for fishes, thus increasing their ability to find food. I examined the response of aquatic plants, macroinvertebrates, and fishes’ weight to carp removal in Utah Lake, UT, to demonstrate that plants and animals can serve as indicators of incremental changes following restoration. Submerged, native, non-woody, and mixed-plant communities were most common when carp were reduced. Macroinvertebrate predators, total unique types, and total weight varied among plant habitat types, where, in general, all were higher in plant habitats than bare sediment. Macroinvertebrate predators were highest in mixed plants, and total weight and total unique types were both much higher in mixed plants than bare sediment. Neither total unique macroinvertebrate types nor total weight were influenced by carp population changes, but white bass (Morone chysops) weight was much greater when carp were reduced. However, other environmental conditions can also influence aquatic plants and animals, and may limit the benefits achieved with carp removal. Indeed, I found that the benefits of carp removal are reduced if water levels are not maintained. Aquatic plants decreased as lake level declined and plant habitat was completely absent at very low lake levels. Additionally, the total unique types of macroinvertebrates and walleye (Sander vitreus) weight both decreased with lower lake levels. Water clarity did not respond to carp population changes, nor did it influence fishes’ weight. Identifying relationships between carp removal, aquatic plants and animals, and other environmental conditions provides a useful framework for detecting incremental changes caused by restoration, while simultaneously capturing the effects of multiple environmental conditions including drought.

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