Predictors of fish occurrence and scale dependence in wadeable streams

David H. Keller

doi:10.17918/00001899

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Predictors of fish occurrence and scale dependence in wadeable streams

Dissertation

Open access

Predictors of fish occurrence and scale dependence in wadeable streams

David H. Keller

Doctor of Philosophy (Ph.D.), Drexel University

Jun 2020

DOI:

https://doi.org/10.17918/00001899

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Spreadsheet (supplemental)Reproductive guild occurrence at 552 sites in the Delaware River basinOpen Access (License Unspecified), Open Access

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Spreadsheet (supplemental)Reproductive guild proportions at 552 sites in the Delaware River basinOpen Access (License Unspecified), Open Access

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Spreadsheet (supplemental)Geospatial variable values for 552 sites in the Delaware River basinOpen Access (License Unspecified), Open Access

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Spreadsheet (supplemental)Effect sizes of terms used in multiple logistic regression modelsOpen Access (License Unspecified), Open Access

Abstract

dam

disturbance

habitat

landscape

microhabitat

predator

Species dependent on freshwaters are declining globally, requiring a better understanding of natural and anthropogenic environmental drivers affecting community structure and species occurrence. More so, to effectively conserve and manage fishes, practitioners need a detailed understanding of the factors and major gradients that influence or explain fish distributions on multiple scales. Here, I determine which landscape features most strongly constrain reproductive guilds in wadeable streams and explore the influence of reproductive strategy on fish occurrence. I investigate the scale dependencies for fish-habitat associations by using variables summarized on reach- and microhabitat-scales. Lastly, I assess the scale dependencies of fish habitat associations and their response to dam removal and increased predator occurrence. My findings suggest a link between the environmental requirements of reproductive guilds and landscape-scale determinants, particularly slope. My results provide support for the concept of environmental filtering at the reach and microhabitat scales and corroborate other studies that have found environmental variables influence the distribution and abundance of fishes across multiple spatial scales. Additionally, my findings suggest that predator-prey interactions may alter habitat associations and scale dependencies. My analyses highlight the importance of considering scale when assessing fish response to environmental changes such as dam removal and instream habitat. This research highlights the factors that influence fish occurrence and/or abundance, identifies the scales on which specific fish habitat associations depend and informs multi-scale conservation and management of fishes in wadeable streams.

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Title: Predictors of fish occurrence and scale dependence in wadeable streams
Creators: David H. Keller
Contributors: Susan Soltau Kilham (Advisor)
Richard J. Horwitz (Advisor)
Awarding Institution: Drexel University
Degree Awarded: Doctor of Philosophy (Ph.D.)
Publisher: Drexel University; Philadelphia, Pennsylvania
Number of pages: xiii, 157 pages
Resource Type: Dissertation
Language: English
Academic Unit: Biodiversity, Earth, and Environmental Science (BEES); College of Arts and Sciences; Drexel University
Other Identifier: 991014695536704721

Predictors of fish occurrence and scale dependence in wadeable streams

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