AUTHORS: Connor S. Church, University of Missouri School of Natural Resources; Allison A. Pease, University of Missouri School of Natural Resources
ABSTRACT: In the Central U.S., we are experiencing more frequent extreme high-flow events (floods) in many stream systems associated with climate change. Large swaths of the globe are expected to experience wetter conditions with more frequent, high-magnitude precipitation events in the future. Our objectives were to determine if the effects of extreme flows on fish recruitment are predictable based on life history traits, and to learn how extreme flows affect habitat characteristics and food availability for age-0 fishes. To provide these data, we sampled age-0 fishes by seining in Richland Creek and a side channel of the Lamine River in central Missouri 2023-2024. Each site was surveyed twice monthly from May-September. To characterize food resource availability and quality in relation to flows across the season, we sampled benthic macroinvertebrates using dip net sweeps, and we collected zooplankton using a plankton trap. In 2023, a year with an exceptionally dry spring followed by one summer flood, abundance of age-0 native fishes was low in the Lamine River side channel compared to Richland Creek, Western Mosquitofish, an opportunistic species, predominated in 2023. In 2024, two spring floods occurred, along with multiple rain events during the spring and early summer that allowed floodplain and side channel access to spawning fishes and age-0 individuals. Age-0 individuals of periodic species such as longnose gar, bigmouth buffalo, and skipjack herring were only detected in 2024. Aquatic invertebrate diversity and abundance were higher in 2023 than in 2024. Our research will help address how timing, frequency, and magnitude of flow events affect recruitment in stream fish assemblages.
