Habitatpreferenser hos den invasiva lövplattmasken (Obama nungara)

Sammanfattning

The South American species Obama nungara has spread to several European countries over the past decade, raising great concern due to its potential to negatively affect soil biodiversity. Despite increased research, little is still known about the species' ecological requirements and its potential dispersal routes. The aim of this study was therefore to investigate whether O. nungara exhibits a preference for a certain soil type, with the hypothesis that the species prefers soils with low pH. In a laboratory experiment, eleven adult individuals were offered a choice between four soil types with varying pH and nutrient content. After 24 hours, each individual's position was noted as an indicator of its preferred soil type. The choices were analysed with a one-sample Wilcoxon signed-rank test to test whether the individuals' habitat choices deviated from a random distribution. The results showed that O. nungara avoided soils with a higher pH, and the hypothesis is thus partially supported. Most observations were made in the most acidic soil followed by the most nutrient-rich soil, suggesting that pH may not be the only factor influencing habitat selection. The study provides new insights into the behaviour and habitat selection of O. nungara and the results can be used to predict the species’ potential spread.