Increasing temperature and decreasing specific leaf area amplify centipede predation impact on Collembola

Collembola is an abundant group of soil organisms playing a major role on litter decomposition process and nutrient cycling in forest ecosystems. Habitat structure strongly influences Collembola assemblages as plant litter physical characteristics and quantity provide structural niches and determine the outcome of their interactions with predators. Collembola are also extremely sensitive to environmental conditions such as soil temperature that control their demographic parameters and activity. In this context, increasing temperature with the ongoing climate change can have strong impact on Collembola assemblages and their responses to predation either directly by altering their behaviour or indirectly by altering their habitat structure. We therefore examined how the increase of temperature combined to the decrease of specific leaf area (SLA, a major functional plant trait) of the European common oak (Quercus robur L.) and the presence of a centipede predator (Chilopoda: Lithobiidae) will affect the abundance of Folsomia candida (Collembola: Isotomidae) in a 5-week microcosm experiment. Increasing temperature, decreasing SLA and presence of centipede altered F. candida abundance. We observed a significant temperature × predation interaction suggesting differential effects of increasing temperature on F. candida abundance with and without predator. We also observed a significant SLA × predation interaction highlighting that lower SLA decreases F. candida abundance only in predator presence. Finally, our findings evidenced that increasing temperature and decreasing SLA amplify the negative effect of centipede predation on F. candida abundance, suggesting that both direct and indirect effects of climate change would conjointly strengthen the top-down control of predators on preys.