Fertilization and drought: Is species drought resistance affected by trait plasticity in response to nutrients?

Carola Kiene, Bettina Engelbrecht

P 5.4 in Open Poster Session

Water and soil nutrient availability are two main factors shaping grasslands. However, we lack a thorough understanding of how nutrients impact grassland responses to drought through trait attribute changes and phenotypic plasticity. We examined the plasticity of 21 functional traits hypothesized to be relevant for plant drought performance, in response to 3 different nutrient conditions (nitrogen addition [N], phosphorus addition [P] and combination of NP) in13 common temperate grassland species, We assessed the coordination of traits and their plasticity in principal component analyses, and consequently examined, which trait combinations determine drought resistance (i.e., the ability to maintain functioning during drought) and drought resilience (i.e., the capacity to minimize long-term function loss compared to unstressed plants) under different nutrient conditions. Traits relevant for drought performance were plastic in response to nutrients, with direction and strength varying widely across species and nutrients. Independent of nutrient conditions, species with high water uptake exhibited higher drought resistance than species that maintained high leaf water potentials. Coordinated shifts towards higher water uptake with nutrient addition explained drought resilience. Our results highlight the necessity of understanding the role of belowground and aboveground traits in more detail, to predict species' response to global change drivers. Our results highlight the necessity of understanding the role of belowground and aboveground traits in more detail, to predict species' response to global change drivers.



Keywords: Climate extremes, Grasslands, Drought sensitivity, Trait plasticity, Trait coordination