Fish invasion alters ecosystem function in a small heterotrophic stream
The strength of trophic cascade effects in aquatic ecosystems depend, in part, on the identity of the top predator involved. We examined whether an invasive benthic fish (round goby, Neogobius melanostomus) altered the strength of cascade effects in a heterotrophic stream and in a controlled mesocosm experiment relative to the effects of a functionally similar, native fish. In the stream, the introduced fish had a direct effect on grazer and shredder abundance which led to a significant increase in periphyton chlorophyll a, a significant reduction in leaf breakdown rate, an increase in leaf biomass remaining, but no change in periphyton ash-free dry mass. In mesocosms, native and introduced fish similarly reduced shredder abundance, but this did not lead to an indirect effect on leaf breakdown rates or biomass remaining at the end of the experiment. Indirect effects of introduced fish on periphyton biomass and chlorophyll a in mesocosms were both significant and were stronger than in the field, but were the result of grazer behavioral modification and not reduced grazer abundance. Collectively, these results suggest non-native fish have the ability to initiate trophic cascades in heterotrophic streams, and that both fish identity and environmental context are important in determining the strength of cascades.
KeywordsNeogobius melanostomus Trophic cascade Leaf litter decomposition Periphyton
Parts of this research were supported by an NSF, URM award (DEB No. 0731582) to CMP and supporting CEJ. Special thanks to the BSC Field Station manager, Mark Clapsadl, for securing the mesocosm location and logistics.
- Bode RW, Novak MA, Abele LE, Heitzman DL, Smith AJ, Carlson D (2002) Ellicott Creek biological assessment, 2001 survey. Stream Biomonitoring Unit, Bureau of Watershed Assessment and Research, Division of Water, NY Dept of Environmental Conservation. 43 ppGoogle Scholar
- Copp GH, Bianco PG, Bogutskaya N, Erös T, Falka I, Ferreira MT, Fox MG, Freyhof J, Gozlan RE, Grabowska J, Kováč V, Moreno-Amich R, Naseka AM, Peňáz M, Povž M, Przybylski M, Robillard M, Russell IC, Stakénas S, Šumer S, Vila-Gispert A, Wiesner C (2005) To be, or not to be, a non-native freshwater fish? J Appl Ichthyol 21:242–348CrossRefGoogle Scholar
- Fischer AM (2014) Effects of round goby presence on invertebrate and microbial communities in decaying leaf matter of a Lake Erie tributary stream. Biology Theses 12. http://digitalcommons.buffalostate.edu/biology_theses/12
- Fuller P, Benson A, Maynard E, Neilson M, Larson J, Fusaro A (2017) Neogobius melanostomus. USGS Nonindigenous Aquatic Species Database, Gainesville, FL. https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=713. Revision date 1/7/2016
- Mikl L, Adámek Z, Všetičková Janáč M, Roche K, Šlapansky L, Jurajda P (2017) Response of benthic macroinvertebrate assemblages to round (Neogobius melanostomus, Pallas 1814) and tubenose (Proterorhinus semilunaris, Heckel 1837) goby predation pressure. Hydrobiologia 785:219–232CrossRefGoogle Scholar
- Schmitz OJ (2010) Resolving ecosystem complexity. Monographs in population biology, No. 47. Princeton Univeristy Press, PrincetonGoogle Scholar
- Weimer MT (2003) The distribution of round goby (Neogobius melanostomus) in Eighteenmile Creek, Erie County, New York. Aquat Invader 14:2–4Google Scholar