Wie individuelle Verhaltensunterschiede in Räuber-Beute-Beziehungen den Erfolg invasiver Arten beeinflussen
Zusammenfassung der Projektergebnisse
Invasions are a growing problem in our increasingly globalized world. However, predicting what factors contribute to the success or demise of a potential invader is still very difficult. Here, this project investigated how behavior may mediate species interactions and whole ecosystem functions to test whether behavioral patterns can predict the success of a potential invader. We first tested whether and how a highly invasive amphipod, Dikerogammarus villosus, differs in behavior from other native amphipod species. While most invasive species are predicted to exhibit ‘invasion syndromes’ characterized by high levels of activity and dispersal which should increase their ability to invader new habitats. Contrary to these expectations we instead found that the invasive amphipod, exhibited extraordinarily sedentary behavior. We then tested the functional role of this behavior and found that when encountering a native fish predator, this amphipod was far less likely to be consumed. This research suggests invaders that occupy lower trophic levels, that is, are subject to predation, may benefit from different behavioral strategies than those invaders without predators in their new environment. We then tested whether and how the behavior within a native predator population may alter the interaction among species within a food web with the goal of predicting whether some predator behaviors are more successful at limiting invasions by invasive prey. We placed groups of perch with different behavioral strategies into replicated ponds. All perch in a pond either exhibited active and bold behaviors, shy and inactive behaviors or were a mix of the two. Finally, we measured several aspects of food web dynamics including predator growth rates, their consumption of invertebrate prey and basal resource responses (leaf litter decomposition and periphyton growth). Interestingly, we found that the behavior of the predators influenced their own growth rate: bolder perch were more successful when they were placed in ponds with a mix of behavioral phenotypes compared to in ponds with all bold individuals. Counter our expectations we did not however find that these behavioral differences influenced other aspects of the food web: there were no differences in prey consumption or basal resource dynamics. This suggests that the behavior of native predators communities may have less influence on the ability of potential invasive prey to succeed in a novel environment than previously expected. This project was part of the focus of the “Wissenschaft im Brennpukt” program on Deutschlandfunk (“Gesellschaft unter Wasser: Soziale Nezwerke bei Molly und Muräne”). Finally, we tested whether behavioral differences in predators can have impacts on larger more natural ecosystems. Here we took advantage of the kleiner Döllnsee, a natural lake located about 80km north of Berlin. Importantly, this lake is outfitted with several acoustic telemetry receivers which allow us to follow the activity and position of any fish in the lake that has been tagged with acoustic transporders. Using this system we found that, just as in the perch, wild pike exhibit strong and consistent behavioral differences in the wild that were consistent over nearly an entire year. These behavioral differences importantly correlated with a number of other important traits including growth rates and survival suggesting that these behavioral differences can have important individual fitness consequences. Additionally these behavioral differences predicted a pike’s foraging strategies including diet composition and foraging location suggesting that individual differences in pike behavior can have consequences on entire lake food webs and thus ecosystem functions.
Projektbezogene Publikationen (Auswahl)
- 2016. Highly variable, unpredictable activity patterns in invasive, but not native amphipod species. Aquatic Ecology 50: 261-271
Bierbach, D., K.L. Laskowski, A.-L. Brandt, W. Chen, J. Jourdan, B. Streit, M. Plath
(Siehe online unter https://doi.org/10.1007/s10452-016-9573-4) - 2018. Defense is the best offense: invasive prey behaviour more important than native predator behaviour. Animal Behaviour 138:157.164
Mennen, G.J., K.L. Laskowski
(Siehe online unter https://doi.org/10.1016/j.anbehav.2018.02.017)
