Assessment of the occurrence and abundance of an exotic zooplankton species (Kellicottia bostiniensis) across a neotropical wetland over 12 years.

Understanding how the occurrence and abundance of invasive species vary over time and the environmental factors that cause such variation is important for managing and controlling invasive species. To date, studies with this perspective remain scarce in the Neotropics. We used a database describing 12 years of the occurrence of an invasive rotifer (Kellicottia bostoniensis) in a large neotropical wetland (230 km2) (upper Paraná River) since 2000. We investigated how multiple local abiotic and biotic environmental variables jointly affect occurrence and abundance of an invasive zooplankton species (K. bostoniensis). The abundance and occurrence of K. bostoniensis varied significantly over time, with a marked increase after 2009. Furthermore, biotic (native zooplankton abundance, chlorophyll-a) and abiotic (turbidity, and water level) variables were important drivers of K. bostoniensis. Whereas native zooplankton and turbidity were negatively associated with the occurrence and abundance of K. bostoniensis, chlorophyll-a and water level were positively related. Furthermore, as biotic and abiotic variables naturally fluctuate to extremes, the occurrence and abundance of K. bostoniensis were reduced. Collectively, our findings underline the important role of local variables, particularly, native zooplankton and turbidity to control the abundance and occurrence of K. bostoniensis. Our results also suggest that maintaining natural extreme oscillations of the local variables can be effective in the management of invasive species. [ABSTRACT FROM AUTHOR]