MASTER THESIS opportunity in plant tropical ecology

Can nutrient addition change foliar reabsorption efficiency?

Nutrient resorption (the withdrawal of nutrients from senescing leaves) is a critical nutrient conservation strategy allowing tropical forests to thrive on nutrient-poor substrates. Studies covering large environmental gradients have noted shifts in community-wide nutrient resorption, but the intraspecific plasticity of such strategies remains unclear [1]. Here, we will test how long-term addition of nitrogen (N) and phosphorus (P) influence leaf resorption efficiency, and how this is related to biomass production in a large-scale factorial fertilization experiment in French Guyana.

Available data

Data from stem diameter, green leaf and senesced leaf chemical composition was collected in 2019, after 4 years of fertilization in the low-land tropical forest in French Guyana (2 sites, Paracou and Nouragues). Ancillary data from soils, roots and environment are also available for complementary data analysis. The site resorption information was analysed before fertilization [2] and the site has shown evidence of both N and P limitation after 4 years of N and P fertilization [3].

Reference papers

[1] Sophia, G., Caldararu, S., Stocker, B. D., and Zaehle, S.: Leaf habit drives leaf nutrient resorption globally alongside nutrient availability and climate, Biogeosciences, 21, 4169–4193, https://doi.org/10.5194/bg-21-4169-2024, 2024.

[2] Urbina I, Grau O, Sardans J, et al. High foliar K and P resorption efficiencies in old-growth tropical forests growing on nutrient-poor soils. Ecol Evol. 2021; 11: 8969–8982. https://doi.org/10.1002/ece3.7734

[3] Vallicrosa, Helena, Laynara F. Lugli, Lucia Fuchslueger, Jordi Sardans, Irene Ramirez-Rojas, Erik Verbruggen, Oriol Grau, et al. 2023. “ Phosphorus Scarcity Contributes to Nitrogen Limitation in Lowland Tropical Rainforests.” Ecology 104(6): e4049. https://doi.org/10.1002/ecy.4049

Dr. Helena Vallicrosa Pou

[email protected]

Plant Ecology Research Laboratory – PERL

Ecole polytechnique fédérale de Lausanne (EPFL) et

Institut fédéral de recherches WSL, Site Lausanne

Station 2, CH – 1015 Lausanne (Switzerland)