Is All Heterogeneity Created Equal? How Types of Habitat Heterogeneity Differentially Alter Distribution, Abundance, and Diets of Age-0 Largemouth Bass

Heterogeneity is ubiquitous in aquatic ecosystems and can dramatically alter ecological patterns and processes. Aquatic ecologists and fisheries biologists often examine variation in structure and function within and across habitats. Landscape ecologists frequently test questions about habitat mosaics. However, the impacts of within-patch, across-patch, and within-mosaic heterogeneity are rarely compared. To address this information gap, here we test if three types of heterogeneity differentially affected age-0 largemouth bass distribution, abundance, and diet in four habitats across nine sites in Hillsdale Reservoir, KS, during 2014. Within patch variation existed in habitat and fish characteristics [e.g. for vegetated habitats, stem density (0-73 stems per 56 cm²), stem coverage (0-58% stems per patch area), and CPUE (0-33 fish/100m²)]. Mean CPUE across patches differed (vegetation = 1.21, beach = 1.23, offshore = 0.05, rocky = 0.38). Patch mosaic affected local habitat responses in that CPUE within one patch was influenced by neighboring patch CPUE (mean r²= 0.6044). Consequently, these three categories of habitat heterogeneity have different impacts on fish populations. An understanding of the scope of habitat heterogeneity will help us understand general drivers of distribution and abundance in aquatic systems and manage across system and across year variations in fish populations.