Linking range-expansion of plants with trophic downgrading in the soil

• Applicant: Dr. Madhav Thakur
• Subject Area: Ecology and Biodiversity of Plants and Ecosystems
• Term: from 2017 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 396714173

The two well-known responses of species to climate change are: northward expansion of species, such as range-expansion of plants and loss of higher trophic group organisms, such as decline of predators. However, we know very less how these two responses facilitate or constrain each other. For instance, the loss of soil predators can detrimentally affect nutrient turnover in the soil with a negative effect on the success of range-expanding plant species. Here, I propose to experimentally test how losses of soil predators may influence the performance of northward expanding plant species in its new geographic range. For this, I will use a vigorously northward expanding plant - Centaurea stoebe- from a European south-north transect (Spanning from Slovenia in south to the Netherlands in north). I aim to experimentally test the competitive interactions between the C. stoebe with its naturally co-occurring congener and a native species across the transect-Centaurea jacea- with and without soil predators. The soil food webs will be extracted from the rhizosphere of the respective plants from south (Slovenia) and north locations (the Netherlands). I will use different food web motifs assembled with microbial communities (bacteria and fungi) and their predators (bacterial- and fungal-feeding nematodes) as well as top predators (predatory nematodes) in this experiment. I hypothesize that the presence of predators will enhance the performance of C. stoebe over C. jacea in the northern soils, as predator-induced nutrient turnover would benefit C. stoebe over C. jacea. This hypothesis corresponds to studies showing nutrient availability as the key-limiting factor for plant species to establish in the new range. The results of these experiments will provide several novel insights, particularly towards establishing a predictive link between the alteration of trophic interactions and the range-expansion of plant species-the two crucial biotic responses to global climate change.

• DFG Programme: Research Fellowships
• International Connection: Netherlands
• Host: Professor Dr. Wim van der Putten