Experimental set-ups
FertiGuyane
FertiGuyane: Effect of changes in nutrient availability on the functioning of tropical forest ecosystems
Created
The fertilisation experiment was initiated in 2014 - 2015 in the context of the IMBALANCE-P project (ERC Synergy Grant 2013 - 610028) at both research stations, Paracou and Nouragues, in French Guiana.
Context
Tropical forests influence the global carbon cycle, yet our understanding of how these forests will respond to various global change drivers remains uncertain. The productivity of tropical forests is affected by a variety of potentially limiting resources: light, water and nutrients. However, the degree to which nutrient availability constrains plant growth in different ecosystem contexts, the components affected (i.e. radial growth, root and leaf production), and even the identity of these nutrients (e.g. nitrogen (N) and phosphorus (P)) remains highly contentious. One approach to gain insights into nutrient limitation is through nutrient addition treatments applied to replicate forest plots.
Objective
To study the responses of tropical forest ecosystems to large-scale nutrient additions, with the aim of providing a framework for how nutrient availability shapes ecosystem processes such as carbon and nutrient cycling, plant productivity, plant community composition and their functional traits, and species coexistence.
Methods
At each site, Paracou and Nouragues, the experimental design includes 12 plots of 0.25 ha each, established along a topographical gradient characterized by three forest zones with naturally contrasting soil conditions. The soils of the hill-top plots (terra firme) are well drained but poor in nutrients, in contrast to those of the lowland (hill-bottom) plots, which are regularly saturated with water and rich in nutrients. Soils on the slope plots are intermediate. Each of the three groups of four plots has a plot fertilsed with 125 kg N ha-1 year-1, a plot fertilised with 50 kg P ha-1 year-1, a plot fertilised with a mixture of N and P (125 +50 kg N / P ha-1 year-1) and a control plot (undisturbed forest).
