Biotic Integrity and Northern Pike Ecology in Eastern South Dakota

Ecosystem goods and services in streams are impaired when their biotic communities are degraded by anthropogenic stressors. An index of biotic integrity (IBI) translates community structure into a standardized stream health score. Documenting stream health is important in the Northern Glaciated Plains (NGP) Ecoregion, which is undergoing rapid landscape alterations because of increased agricultural production. Understanding sport fish ecology in prairie streams, garners important public support for protecting stream biotic integrity. Thus, our objectives were to (1) develop a fish IBI and validate reference sites, and (2) quantify the age, growth, and diet of the important sport species northern pike Esox lucius in the wadeable perennial streams of the NGP. For IBI development, fish were sampled from 54 sites (sites span a gradient of human disturbance). Candidate metrics were sorted into metric classes and screened using a series of statistical tests. The final IBI consisted of five metrics that differentiated between known-condition least and most disturbed sites. Eleven reference site scores were below the NGP median (62), whereas the other 12 sites were above the median and were representative of least disturbed conditions. We now have a standardized bioassessment tool for evaluating stream health, as well as a baseline for long-term monitoring in a dynamic ecoregion. To advance knowledge on northern pike ecology, pike were sampled from 14 streams. Growth was estimated with a von Bertalanffy growth model relating total length to ages estimated from scales and cleithra. Prey importance was assessed with mean percentage by number and weight of diet items, and northern pike prey specificity was evaluated with prey-specific abundance and frequency of occurrence. Seventy-five percent of all northern pike collected were juveniles age-0 to 2. Lotic northern pike growth rates from the NGP were slower than lentic rates across the Great Plains. Age-0 northern pike fed on a wide range of vertebrate and invertebrate prey items, whereas older pike were mainly piscivores that opportunistically fed on invertebrates. These results indicate that NGP streams support northern pike reproduction and growth of juvenile pike. Sport fish production is a valuable ecosystem function provided by NGP streams where biotic integrity is maintained.

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Thesis - University Access Only

Discipline thesis:degree_discipline

Natural Resource Management

Year

2013

Author dc:creator

• Krause, Jacob R.

Contributors dc:contributor

• Katie N. Bertrand

• Natural Resources and Conservation

Statement dc:rights

• Copyright © 2013 Jacob R. Krause. All rights reserved.

Language dc:language

en

Repository record dc:identifier

https://openprairie.sdstate.edu/etd/510

OAI identifier oai:identifier

oai:openprairie.sdstate.edu:etd-1510