Long-distance dispersal in macroinvertebrates as a prerequisite of climate change driven range shifts and recolonization of restored rivers: A multi-method approach

Background/Question/Methods

Climate change driven range shifts or the recolonization of restored habitats can only be realized by organisms with a sufficient dispersal capacity. Several studies consider short distance dispersal, whereas our knowledge about long distance dispersal of hololimnic and merolimnic macroinvertebrates is scarce. This is mainly due to a growing “dilution effect” with increasing distance.

To overcome this dilution effect, we present the results from three complementary approaches: 1) data mining, 2) a literature review on macroinvertebrate dispersal, and 3) population genetics. Dispersal strategies were categorized in active and passive, and sub-classified in aquatic, aerial, and terrestrial. We further distinguished between within-stream and between-stream dispersal and also assessed the speed of dispersal by providing dispersal distances in kilometer per year.

Results/Conclusions

All three approaches provide relatively short distances for hololimnic taxa and aquatic larvae of merolimnic taxa. Even adults of winged merolimnic taxa usually only move short to intermediate distances, although there are a few reports of occasional historical or recent long-distance dispersal. The results thus support the idea that the spread of, and quick recolonization by, macroinvertebrates usually is limited by their dispersal capability in addition to potential habitat filters in restored sites. Dispersal limitations can be overcome by using aquatic, aerial, or terrestrial vectors (passive dispersal).

Our results point to the need of advanced river restoration strategies that integrate and facilitate landscape-wide networks. Concerning climate change our data could be used in advanced species distribution modeling (SDM) to improve our knowledge on climate change driven macroinvertebrate range shifts.