Links between two interacting factors, novel habitats and non-native predators, and aquatic invertebrate communities in a dryland environment

In dryland regions, increased demand for water has led to the reduction of natural aquatic habitats and threatens persisting aquatic habitats. In the Madrean Sky Islands (MSI), water demands have also resulted in the creation of novel aquatic habitats, including stock ponds. Stock ponds are important surrogate habitat for native species, yet little is known about the aquatic invertebrates utilizing these habitats. Additionally, stock ponds support non-native vertebrate predators including American bullfrogs (Lithobates catesbeiana) and Western mosquitofish (Gambusia affinis), and the effects of these predators on invertebrate communities in stock ponds are unknown. We explored similarities in invertebrate communities in stream pools and stock ponds and compared aquatic invertebrate community composition, abundance, and richness in stock ponds with and without non-native predators. We found that despite considerable functional (trait-based) overlap in aquatic invertebrate communities, a large majority (81%) of taxa were exclusive to either stock ponds or stream pools. Additionally, we observed few differences in aquatic invertebrate community composition, abundance, and richness in stock ponds with and without non-native predators. We discuss ecological implications of our observations, limitations of our approach, and the importance of future work in determining the role of stock ponds in conservation of the region’s aquatic invertebrates.