Vegetation response to climate change: a traits-based approach

Focusing on South Africa and on root traits

Nicola Kühn‘s DPhil research investigates the role that traits play in determining vegetation response to climate change with a specific focus in South Africa and on root traits. This work includes three primary objectives:

Objective 1: To identify through a systematic review of literature whether current studies indicate a global, general set of trait-environment relationships that underlie positive species responses to climate and associated environmental change. To fulfil this objective, we pose the following research questions:

• Which are the top traits across both biomes and climate/environmental changes that mediate positive responses in terms of plant fitness and performance to climate change?
• What are the attributes (values or states) of these traits that confer a positive plant response to climate change?
• Do these trait attributes vary across biomes and climate/environmental changes?

Objective 2: To quantify trait variation of below and aboveground traits across water availability gradients in woody Fynbos shrubs of South Africa. To fulfil this objective, we pose the following research questions:

• How do traits vary across water availability gradients (precipitation and topography)?
• Do we observe intraspecific trait variation across these water availability gradients?
• How do dominant traits in recently burnt vegetation differ from more mature/unburnt vegetation?
• How important are root traits in overall trait variation across these water availability gradients?
• Is the belowground vs aboveground investment different in drier conditions?

Objective 3: To determine whether deeper roots are associated with lower vegetation sensitivity (VSI) to climate in South Africa. To fulfil this objective, we pose the following research questions:

• What is the relationship between root depth and VSI and, coefficient T-1 (climate conditions a month before)?
• How does this relationship vary across different biomes?
• In areas where root depth and VSI have an expected negative trend or CT-1 an expected positive trend, is there a decoupling in the relationship between EVI and precipitation?

Publications

Nicola Kühn, Marcus P Spiegel, Carolina Tovar, Katherine J Willis and Marc Macias-Fauria, "Seeing roots from space: aboveground fingerprints of root depth in vegetation sensitivity to climate in dry biomes" Environmental Research Letters, 17(11) 2022. DOI 10.1088/1748-9326/ac9d4f

Nicola Kühn, Carolina Tovar, Katherine J Willis, and Marc Macias‐Fauria, Root trait variation along water gradients in the Cape Floristic Region, Journal of Vegetation Science, 34(3) 2023.  https://doi.org/10.1111/jvs.13194