Amanda E. Rosenberger William J. Kane Mark S. Wipfli Christian E. Zimmerman Sarah M. Laske 2017 <p><span>Despite their widespread presence in northern-latitude ecosystems, the ecological role of Ninespine Stickleback&nbsp;</span><i>Pungitius pungitius</i><span><span>&nbsp;</span>is not well understood. Ninespine Stickleback can occupy both top and intermediate trophic levels in freshwater ecosystems, so their role in food webs as a predator on invertebrates and as a forage fish for upper level consumers probably is substantial. We introduced Ninespine Sticklebacks to fishless ponds to elucidate their potential effects as a predator on invertebrate communities in Arctic lentic freshwaters. We hypothesized that Ninespine Stickleback would affect freshwater invertebrate communities in a top-down manner. We predicted that the addition of Ninespine Sticklebacks to fishless ponds would: 1) reduce invertebrate taxonomic richness, 2) decrease overall invertebrate abundance, 3) reduce invertebrate biomass, and 4) decrease average invertebrate body size. We tested our hypothesis at 2 locations by adding Ninespine Stickleback to isolated ponds and compared invertebrate communities over time between fish-addition and fishless control ponds. Ninespine Sticklebacks exerted strong top-down pressure on invertebrate communities mainly by changing invertebrate taxonomic richness and biomass and, to a lesser extent, abundance and average invertebrate size. Our results supported the hypothesis that Ninespine Stickleback may help shape lentic food webs in the Arctic.</span></p> application/pdf 10.1086/690675 en The University of Chicago Press Top-down control of invertebrates by Ninespine Stickleback in Arctic ponds article