Comparison of Fish Communities and Abundance Over Various Existing and Added Habitats in Nebraska Reservoirs

ABSTRACT

Physical structures, constructed from either natural or artificial materials, are added to aquatic systems to provide habitat for fish. Attraction to new structures is well documented, but few studies have compared attraction on added structures to existing or bare areas in multiple reservoirs or species. Thus, the objective of this study was to compare species richness and diversity and abundances of target taxa over newly added structures constructed of different materials to those over nearest existing available habitat and an open site with no apparent habitat structures within three reservoirs where sampling was conducted across seasons and years. Cedar brush piles and Georgia cube complexes were placed in into three reservoirs in October 2020. Existing physical habitats and areas devoid of any physical structure were also selected near added structures. Sampling was conducted in spring, summer, and fall 2021 and 2022 using boat‐mounted electrofishing. Richness and diversity were generally higher over existing or added structure than over open habitat. However, none of our target taxa showed consistent association to a single habitat type between reservoirs, and seasonal differences in habitat use were common. Our results point towards the need to understand the inherent factors, such as existing habitat availability, the recipient fish community, and abiotic factors on the outcomes of adding physical habitat structure in reservoirs. Continuous monitoring over multiple years beyond the timeframe of this research is recommended to provide information on the longevity of benefits to fishes and to decide when habitat structures may need to be replaced.