Staying or leaving: Triggers of emigration
Final Report Abstract
Distribution is a vital component of the life-history of nearly all organisms. The ability to disperse determines the distribution and abundance of a species and thus its community dynamics at different sites. Dispersal is a multifactorial process, one that includes fundamental factors such as population density, the availability of food resources, and the presence of predators. As part of our project, we designed an experimental setup to investigate the interaction of these environmental factors on the emigration of nematodes under standardized laboratory conditions. The results suggest that these small worms are an appropriate model organism to study the multicausality of active dispersal, since the large number of individuals and species that can be confined in a small area and tested in a relatively short time allows the drivers of dispersal to be investigated in detail. Moreover, the experimental design allowed us to compare the reactions of different species and, for the first time, to observe the emigration processes of an entire community. We were able to show that dispersal is a highly complex process, since the examined factors evoked different emigration behaviors and interacted strongly with one another. The most important factor was the availability of food resources, as demonstrated both for nematodes from laboratory cultures and for a natural nematode community. However, in addition to the impact of environmental factors, emigration was shown to be species-specific and influenced by interspecific interactions. For example, emigration was stronger in faster-reproducing species. Thus, dispersal is much more than the response to the sum of the single factors but is also influenced by their interactions. Our experiments demonstrate the importance of considering interactive effects in investigations of dispersal triggers and thus the need for high-level experimental complexity, i.e., the inclusion of many factors in the analyses. Moreover, our findings are in contrast to those of previous studies, the majority of which focused on single factors and differed in their experimental design, such that their results are not readily comparable.
Publications
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It's all about food: Environmental factors cause species‐specific dispersal. Ecosphere, 13(10).
Kreuzinger‐Janik, Bianca; Gansfort, Birgit; Traunspurger, Walter & Ptatscheck, Christoph
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Population density, bottom-up and top-down control as an interactive triplet to trigger dispersal. Scientific Reports, 12(1).
Kreuzinger-Janik, Bianca; Gansfort, Birgit & Ptatscheck, Christoph
