Co-occurrence patterns between native and non-native species

Non-native species may cause cumulative impacts on native communities if their abundance continues to increase through time. This negative effect can reflect on the spatial distribution of native species, especially when native and non-native species are phylogenetically similar. Here, we assessed the spatial co-occurrence between native and non-native fish species using long-term abundance data from six locations in a Brazilian floodplain. We tested whether the co-occurrence of native and non-native species is influenced by non-native species abundance and time since first record, and whether the abundance effect is mediated by the phylogenetic relatedness between native and non-native species. We found that non-native abundance was more influential than the time since first record and co-occurrence between native and non-native species was lower when the non-native abundance was high, regardless of phylogenetic relatedness. The interannual variability in non-native species abundance may overshadow long-term trends in determining the temporal effects of non-native species.