Amphibian larvae distribution amongst intermittent stream pools in the Flint Hills covaries with vegetation and fish colonization
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Abstract
Climate change is expected to increase the frequency and severity of droughts and precipitation events. The connectivity and hydroperiod among stream pools are expected to change due to these climatic events, therefore influencing what organisms occupy them. Intermittent stream pools in the Great Plains present an idealized replicated system to study the impacts of variable climatic conditions on the distribution of aquatic species, including amphibians. In the Great Plains, intermittent stream pools are the most abundant spawning habitat for amphibians. We sampled 117 stream pools to investigate the effects of fish presence, stream vegetation, hydroperiod, connectivity, and pool volume on larval amphibian distribution, biomass, and density in the Flint Hills of Kansas. Larval amphibians preferred fishless, isolated pools and the effect of volume depended on the connectivity and fish occupancy of that pool (p < 0.05). In small pools where amphibian larvae occurred (n=31), density(g/m3) was higher in pools dominated by macrophyte vegetation and decreased as pool volume increased (p < 0.01). We sampled during a wet year (12.24 inches above the 10-year average) which implies that fish distribution is at a maximum across the streams on this landscape and are having a large effect on the spatial distribution of amphibian larvae. Although more precipitation has the potential to increase the likelihood of larval amphibian presence by filling up more pools, this also increases connectivity among stream pools allowing for increased predatory fish colonization. Understanding how fish and amphibian larvae currently utilize intermittent streams in the Flint Hills will allow us to detect distribution shifts due to climate change.