Physicochemical habitat data and multi-scale occupancy data for spring-associated fishes in Oklahoma streams

Spring-associated fishes occupy thermally unique habitats in groundwater-dominated streams that are often of high quality. However, outside of water temperature, little else is known about the physicochemical habitat requirements for many of these species. With human effects on streams increasing, it is important to conservation and management to characterize spring habitats and the species that occupy them. Our study objective was to determine the physicochemical factors related to occupancy of four spring-associated species in the Arbuckle Uplift and Ozark Highlands ecoregions, Oklahoma USA. We used a hierarchal approach to identify habitat relationships at multiple spatial scales. We collected detection and non-detection data using both snorkeling and seining methods. We examined the physicochemical relationships related to detection and occupancy for four spring-associated fishes. Data were analyzed using occupancy modeling in a Bayesian framework. Our results indicated water depth and water clarity were important factors affecting detection of spring-associated fishes. Occupancy of our target species differed by ecoregion, with least darter being less common in the Ozark Highlands ecoregion and subadult smallmouth bass being more common in the Ozark Highlands. Interestingly, we found water temperature occupancy relationship for only least darter and southern redbelly dace, whereas redspot chub and smallmouth bass were more likely to occur at sites with deeper pool habitats of larger streams. We documented both spatial and temporal differences in occurrence probabilities at ecoregion, reach, and riffle-run-pool complex scale. Furthermore, our results indicate snorkeling was a superior sampling method compared to seining for detecting most fishes in clear warmwater streams even at relatively low visibilities. Lastly, we demonstrate the importance of using multi-scale studies when developing conservation plans for warmwater fishes.