科研之友
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摘要
Determining the temporal or spatial origin of an invasive population is a challenging task as first detections are often made only after the respective species is established. In this study we propose an indirect method for dating introduction events. It is based on the characteristic competition dynamics of two invasive freshwater taxa in Western Europe: the established invader Dreissena polymorpha (zebra mussel) and the recent invader Dreissena rostriformis bugensis (quagga mussel). The underlying assumption is that in sympatric populations, the quagga mussel outcompetes the zebra mussel over time. Thus, relative abundance of the quagga mussel might correlate with time since introduction. On a European scale, we tested this assumption with a combination of data from field samplings and the literature. The correlation analysis confirmed the assumption of a time depended displacement of the zebra mussel by the quagga mussel. In a second step, we calculated the specific rates of displacement based on a regular monitoring of four selected sites in the western part of Europe. These time-series studies revealed an increase of relative abundance of the quagga mussel of 36% per year. We then tested our novel tool by using three case studies, showing that our estimations of quagga mussel introduction events are in concordance with data from independent studies. We propose that our method provides a useful tool to estimate the age of a given quagga mussel population within few years after introduction.
- 出版日期2012-7
