Resource heterogeneity and fish species diversity in lakes

Abstract

We tested the hypothesis that fish species diversity would be positively related to resource diversity in a series of northern and southeastern Ontario lakes. At a macrospatial scale (among lakes), the number of fish species per lake was significantly correlated with two indices of habitat heterogeneity: lake area and the shoreline development factor. At a microspatial scale (among habitats within lakes), detailed analyses revealed several significant correlations between fish species diversity and resource heterogeneity, although some effects of latitude were apparent. Fish species diversity in northern Ontario lakes was positively correlated with the diversity of invertebrate prey (benthos and zooplankton), but not with measures of physical habitat complexity. Species diversity in southern Ontario lakes was positively related to several measures of habitat heterogeneity. Reduction of redundancy in the habitat variables by principal components analysis, followed by multiple regression analyses, showed that fish species diversity in southern lakes was best predicted by substrate diversity and vertical vegetation complexity. Differences in the response of northern and southern fish communities to habitat structure likely relate to glacial history and to characteristics of the different habitats. Our results are consistent with earlier studies and suggest that species diversity – resource diversity relationships, previously reported for terrestrial communities, also apply in aquatic environments.