Periphyton consumption by an invasive snail species is greater in simplified than in complex habitats

Canadian Journal of Zoology, e-First Articles. Habitat complexity may stabilize consumer –resource interactions and reduce the probability of invasion in aquatic habitats. We tested the hypotheses that (i) higher habitat complexity reduces resource consumption independently of grazer species, but that (ii) invasive grazers have a greater influence on decreasing resources independently of habitat complexity. We performed an experiment using artificial substrates to simulate different complexity levels. We evaluated Melanoides tuberculata (O.F. Müller, 1774) and Aylacostoma chloroticum Hylton Scott, 1954 consumption of specific algal groups and the interaction between habitat com plexity and grazer species. Moreover, we evaluated grazer activity on the different substrates during the experiment. The results support only the first hypothesis and indicate lower resource consumption on complex substrates compared with simpler substrates. Additionally, the effect of the grazing of the invasive species on taxon richness was greater in simplified than in complex habitats. The grazing activity on the substrate suggests a relationship between resource exploitation and habitat complexity in which the invasive grazing species visited the simple habitat less frequently. However, the effects of invasive grazers on food resources were higher on the simple substrate. The effects of grazing activity on food resources depend on the interaction between habitat complexity and grazer species. ...

Source: Canadian Journal of Zoology - August 20, 2018 Category: Zoology Authors: Rafael Prandini Tramonte Nicolli Cristina Os ório Fl ávio Henrique Ragonha Gisele Daiane Pinha Liliana Rodrigues Roger Paulo Mormul Source Type: research