Persistence of the non-native Kellicottia bostoniensis (Rousselet, 1908) in a large tropical reservoir

The Brachionidae rotifer Kellicottia bostoniensis (Rousselet, 1908) is a transcontinental invader that continues to spread rapidly from the south to the north of the South American continent. We investigated the invasion of K. bostoniensis and its potential impact on the rotifer assemblage in a large tropical reservoir in southeast Brazil over a period of 9 years. The degree of K. bostoniensis invasion was confirmed by its frequency of occurrence (23%) and constant presence near to the main tributary, thus indicating propagule pressure from upstream. Differing environmental drivers regulated the invader in comparison with resident species. Nitrate and dissolved oxygen were important for native rotifers but not for K. bostoniensis, which negatively correlated with water temperature and positively with epilimnion depth. Total body length of K. bostoniensis increased from 2001 to 2009 as a result of an increase in size of most spines, which suggested a defensive strategy against predation. A functional approach applied to the rotifer assemblage indicated that the high species richness may be associated with high niche partitioning within the assemblage. The permanence of K. bostoniensis in the assemblage appears to be related to occupation of an empty niche.

Automated summary

This study investigated the invasion of Kellicottia bostoniensis and its potential impact on the rotifer assemblage in a large tropical reservoir in southeast Brazil. It was found that the invader had a high degree of invasion and was regulated by different environmental factors compared to resident species.